Update upstream source from tag 'upstream/2.0.0'

Update to upstream version '2.0.0'
with Debian dir 112f2f2cb91158baaf8ee3a1f623980b43a258ce

70 files changed, 12376 insertions, 374 deletions

diff --git a/.gitignore b/.gitignore
index d8537d7..a768d50 100644
--- a/.gitignore
+++ b/.gitignore
@@ -36,4 +36,3 @@ Makefile.in
 # project specific
 build/*
 
-.pc
diff --git a/.travis.yml b/.travis.yml
index be68f7f..b3dd807 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -17,7 +17,7 @@ before_install:
   - if [ $TRAVIS_OS_NAME == osx ]; then brew update && brew install libconfig log4cpp; fi
 
 install:
-  - curl -L https://github.com/nukedzn/psocksxx/releases/download/v1.0.0/psocksxx-1.0.0.tar.gz | tar -zx -C /tmp
+  - curl -L https://github.com/nukedzn/psocksxx/releases/download/v1.1.1/psocksxx-1.1.1.tar.gz | tar -zx -C /tmp
   - cd /tmp/psocksxx-* && ./configure --prefix=/tmp/root && make && make install
   - if [ $TRAVIS_OS_NAME == linux ]; then curl -L http://www.hyperrealm.com/packages/libconfig-1.4.10.tar.gz | tar -zx -C /tmp; fi
   - if [ $TRAVIS_OS_NAME == linux ]; then cd /tmp/libconfig-* && ./configure --prefix=/tmp/root && make && make install; fi
diff --git a/README.md b/README.md
index d003e62..199d1cc 100644
--- a/README.md
+++ b/README.md
@@ -51,8 +51,7 @@ You can download the source distributions from https://github.com/uditha-atukora
 ## Dependencies
 
 * [psocksxx >= 0.0.6](https://nukedzn.github.io/psocksxx/)
-* [libconfig++ >= 1.4](http://www.hyperrealm.com/libconfig/)
-* log4cpp >= 1.0
+* [libconfig++ >= 1.4](https://github.com/hyperrealm/libconfig)
 * python 2.7 (for modpy module)
 
 
diff --git a/changelog b/changelog
index 20d6aad..edecea6 100644
--- a/changelog
+++ b/changelog
@@ -1,8 +1,11 @@
+2.0.0 - 15th June 2018
+	*   Use spdlog instead of log4cpp as the logger (issue #6)
+
 1.0.2 - 19th November 2017
-	*    Fix broken v1.0.1 release
+	*   Fix broken v1.0.1 release
 
 1.0.1 - 19th November 2017
-	*    Make builds reproducible (https://bugs.debian.org/882112)
+	*   Make builds reproducible (https://bugs.debian.org/882112)
 
 1.0.0 - 25th November 2015
 	*   [New] Configurable communication (socket) timeouts
diff --git a/conf/bitz-server.conf.in b/conf/bitz-server.conf.in
index 416a555..5032a70 100644
--- a/conf/bitz-server.conf.in
+++ b/conf/bitz-server.conf.in
@@ -6,7 +6,6 @@ port = 1344;
 
 pid_file     = "@localstatedir@/run/bitz/bitz-server.pid";
 log_file     = "@localstatedir@/log/bitz/bitz-server.log";
-log_category = "bitz-server";
 
 # maximum number of workers
 max_workers         = 1;
diff --git a/configure.ac b/configure.ac
index d972716..199e35a 100644
--- a/configure.ac
+++ b/configure.ac
@@ -2,7 +2,7 @@
 # Process this file with autoconf to produce a configure script.
 
 AC_PREREQ([2.68])
-AC_INIT([bitz-server], [1.0.2], [https://github.com/uditha-atukorala/bitz-server/issues])
+AC_INIT([bitz-server], [2.0.0], [https://github.com/uditha-atukorala/bitz-server/issues])
 AC_CONFIG_AUX_DIR([aux-build])
 AC_CONFIG_MACRO_DIR([aux-build/m4])
 AC_CONFIG_HEADERS([include/config.h])
@@ -49,6 +49,7 @@ AC_PROG_LIBTOOL
 
 # Language
 AC_LANG(C++)
+AX_CXX_COMPILE_STDCXX_11()
 
 # Options
 AC_ARG_WITH([config],
@@ -75,9 +76,6 @@ PKG_PROG_PKG_CONFIG
 PKG_CHECK_MODULES([libconfig], [libconfig++ >= 1.4],,
 	AC_MSG_ERROR([libconfig++ 1.4 or newer not found.])
 )
-PKG_CHECK_MODULES([log4cpp], [log4cpp >= 1.0],,
-	AC_MSG_ERROR([log4cpp 1.0 or newer not found.])
-)
 PKG_CHECK_MODULES([psocksxx], [psocksxx >= 0.0.6],,
 	AC_MSG_ERROR([psocksxx 0.0.6 or newer not found.])
 )
diff --git a/lib/Makefile.am b/lib/Makefile.am
index af3b92e..a02b25d 100644
--- a/lib/Makefile.am
+++ b/lib/Makefile.am
@@ -1,3 +1,7 @@
 ## [bitz-server] lib/
 SUBDIRS = icap
 
+# include spdlog headers in distributions
+EXTRA_DIST = \
+	spdlog
+
diff --git a/lib/spdlog/async_logger.h b/lib/spdlog/async_logger.h
new file mode 100644
index 0000000..75641d2
--- /dev/null
+++ b/lib/spdlog/async_logger.h
@@ -0,0 +1,72 @@
+//
+// Copyright(c) 2015 Gabi Melman.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+//
+
+#pragma once
+
+// Very fast asynchronous logger (millions of logs per second on an average desktop)
+// Uses pre allocated lockfree queue for maximum throughput even under large number of threads.
+// Creates a single back thread to pop messages from the queue and log them.
+//
+// Upon each log write the logger:
+//    1. Checks if its log level is enough to log the message
+//    2. Push a new copy of the message to a queue (or block the caller until space is available in the queue)
+//    3. will throw spdlog_ex upon log exceptions
+// Upon destruction, logs all remaining messages in the queue before destructing..
+
+#include "common.h"
+#include "logger.h"
+
+#include <chrono>
+#include <functional>
+#include <memory>
+#include <string>
+
+namespace spdlog {
+
+namespace details {
+class async_log_helper;
+}
+
+class async_logger SPDLOG_FINAL : public logger
+{
+public:
+    template<class It>
+    async_logger(const std::string &logger_name, const It &begin, const It &end, size_t queue_size,
+        const async_overflow_policy overflow_policy = async_overflow_policy::block_retry,
+        const std::function<void()> &worker_warmup_cb = nullptr,
+        const std::chrono::milliseconds &flush_interval_ms = std::chrono::milliseconds::zero(),
+        const std::function<void()> &worker_teardown_cb = nullptr);
+
+    async_logger(const std::string &logger_name, sinks_init_list sinks, size_t queue_size,
+        const async_overflow_policy overflow_policy = async_overflow_policy::block_retry,
+        const std::function<void()> &worker_warmup_cb = nullptr,
+        const std::chrono::milliseconds &flush_interval_ms = std::chrono::milliseconds::zero(),
+        const std::function<void()> &worker_teardown_cb = nullptr);
+
+    async_logger(const std::string &logger_name, sink_ptr single_sink, size_t queue_size,
+        const async_overflow_policy overflow_policy = async_overflow_policy::block_retry,
+        const std::function<void()> &worker_warmup_cb = nullptr,
+        const std::chrono::milliseconds &flush_interval_ms = std::chrono::milliseconds::zero(),
+        const std::function<void()> &worker_teardown_cb = nullptr);
+
+    // Wait for the queue to be empty, and flush synchronously
+    // Warning: this can potentially last forever as we wait it to complete
+    void flush() override;
+
+    // Error handler
+    void set_error_handler(log_err_handler) override;
+    log_err_handler error_handler() override;
+
+protected:
+    void _sink_it(details::log_msg &msg) override;
+    void _set_formatter(spdlog::formatter_ptr msg_formatter) override;
+    void _set_pattern(const std::string &pattern, pattern_time_type pattern_time) override;
+
+private:
+    std::unique_ptr<details::async_log_helper> _async_log_helper;
+};
+} // namespace spdlog
+
+#include "details/async_logger_impl.h"
diff --git a/lib/spdlog/common.h b/lib/spdlog/common.h
new file mode 100644
index 0000000..e02cb0b
--- /dev/null
+++ b/lib/spdlog/common.h
@@ -0,0 +1,188 @@
+//
+// Copyright(c) 2015 Gabi Melman.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+//
+
+#pragma once
+
+#define SPDLOG_VERSION "0.17.0"
+
+#include "tweakme.h"
+
+#include <atomic>
+#include <chrono>
+#include <exception>
+#include <functional>
+#include <initializer_list>
+#include <memory>
+#include <string>
+#include <unordered_map>
+
+#if defined(_WIN32) && defined(SPDLOG_WCHAR_FILENAMES)
+#include <codecvt>
+#include <locale>
+#endif
+
+#include "details/null_mutex.h"
+
+// visual studio upto 2013 does not support noexcept nor constexpr
+#if defined(_MSC_VER) && (_MSC_VER < 1900)
+#define SPDLOG_NOEXCEPT throw()
+#define SPDLOG_CONSTEXPR
+#else
+#define SPDLOG_NOEXCEPT noexcept
+#define SPDLOG_CONSTEXPR constexpr
+#endif
+
+// final keyword support. On by default. See tweakme.h
+#if defined(SPDLOG_NO_FINAL)
+#define SPDLOG_FINAL
+#else
+#define SPDLOG_FINAL final
+#endif
+
+#if defined(__GNUC__) || defined(__clang__)
+#define SPDLOG_DEPRECATED __attribute__((deprecated))
+#elif defined(_MSC_VER)
+#define SPDLOG_DEPRECATED __declspec(deprecated)
+#else
+#define SPDLOG_DEPRECATED
+#endif
+
+#include "fmt/fmt.h"
+
+namespace spdlog {
+
+class formatter;
+
+namespace sinks {
+class sink;
+}
+
+using log_clock = std::chrono::system_clock;
+using sink_ptr = std::shared_ptr<sinks::sink>;
+using sinks_init_list = std::initializer_list<sink_ptr>;
+using formatter_ptr = std::shared_ptr<spdlog::formatter>;
+#if defined(SPDLOG_NO_ATOMIC_LEVELS)
+using level_t = details::null_atomic_int;
+#else
+using level_t = std::atomic<int>;
+#endif
+
+using log_err_handler = std::function<void(const std::string &err_msg)>;
+
+// Log level enum
+namespace level {
+enum level_enum
+{
+    trace = 0,
+    debug = 1,
+    info = 2,
+    warn = 3,
+    err = 4,
+    critical = 5,
+    off = 6
+};
+
+#if !defined(SPDLOG_LEVEL_NAMES)
+#define SPDLOG_LEVEL_NAMES                                                                                                                 \
+    {                                                                                                                                      \
+        "trace", "debug", "info", "warning", "error", "critical", "off"                                                                    \
+    }
+#endif
+static const char *level_names[] SPDLOG_LEVEL_NAMES;
+
+static const char *short_level_names[]{"T", "D", "I", "W", "E", "C", "O"};
+
+inline const char *to_str(spdlog::level::level_enum l)
+{
+    return level_names[l];
+}
+
+inline const char *to_short_str(spdlog::level::level_enum l)
+{
+    return short_level_names[l];
+}
+inline spdlog::level::level_enum from_str(const std::string &name)
+{
+    static std::unordered_map<std::string, level_enum> name_to_level = // map string->level
+        {{level_names[0], level::trace},                               // trace
+            {level_names[1], level::debug},                            // debug
+            {level_names[2], level::info},                             // info
+            {level_names[3], level::warn},                             // warn
+            {level_names[4], level::err},                              // err
+            {level_names[5], level::critical},                         // critical
+            {level_names[6], level::off}};                             // off
+
+    auto lvl_it = name_to_level.find(name);
+    return lvl_it != name_to_level.end() ? lvl_it->second : level::off;
+}
+
+using level_hasher = std::hash<int>;
+} // namespace level
+
+//
+// Async overflow policy - block by default.
+//
+enum class async_overflow_policy
+{
+    block_retry,    // Block / yield / sleep until message can be enqueued
+    discard_log_msg // Discard the message it enqueue fails
+};
+
+//
+// Pattern time - specific time getting to use for pattern_formatter.
+// local time by default
+//
+enum class pattern_time_type
+{
+    local, // log localtime
+    utc    // log utc
+};
+
+//
+// Log exception
+//
+class spdlog_ex : public std::exception
+{
+public:
+    explicit spdlog_ex(std::string msg)
+        : _msg(std::move(msg))
+    {
+    }
+
+    spdlog_ex(const std::string &msg, int last_errno)
+    {
+        fmt::MemoryWriter writer;
+        fmt::format_system_error(writer, last_errno, msg);
+        _msg = writer.str();
+    }
+
+    const char *what() const SPDLOG_NOEXCEPT override
+    {
+        return _msg.c_str();
+    }
+
+private:
+    std::string _msg;
+};
+
+//
+// wchar support for windows file names (SPDLOG_WCHAR_FILENAMES must be defined)
+//
+#if defined(_WIN32) && defined(SPDLOG_WCHAR_FILENAMES)
+using filename_t = std::wstring;
+#else
+using filename_t = std::string;
+#endif
+
+#define SPDLOG_CATCH_AND_HANDLE                                                                                                            \
+    catch (const std::exception &ex)                                                                                                       \
+    {                                                                                                                                      \
+        _err_handler(ex.what());                                                                                                           \
+    }                                                                                                                                      \
+    catch (...)                                                                                                                            \
+    {                                                                                                                                      \
+        _err_handler("Unknown exeption in logger");                                                                                        \
+    }
+} // namespace spdlog
diff --git a/lib/spdlog/contrib/README.md b/lib/spdlog/contrib/README.md
new file mode 100644
index 0000000..e3abc34
--- /dev/null
+++ b/lib/spdlog/contrib/README.md
@@ -0,0 +1 @@
+Please put here your contribs. Popular contribs will be moved to main tree after stablization
diff --git a/lib/spdlog/contrib/sinks/.gitignore b/lib/spdlog/contrib/sinks/.gitignore
new file mode 100644
index 0000000..8b13789
--- /dev/null
+++ b/lib/spdlog/contrib/sinks/.gitignore
@@ -0,0 +1 @@
+
diff --git a/lib/spdlog/contrib/sinks/step_file_sink.h b/lib/spdlog/contrib/sinks/step_file_sink.h
new file mode 100644
index 0000000..85e24e9
--- /dev/null
+++ b/lib/spdlog/contrib/sinks/step_file_sink.h
@@ -0,0 +1,216 @@
+#pragma once
+
+#include "../../details/file_helper.h"
+#include "../../details/null_mutex.h"
+#include "../../fmt/fmt.h"
+#include "../../sinks/base_sink.h"
+
+#include <algorithm>
+#include <cerrno>
+#include <chrono>
+#include <cstdio>
+#include <ctime>
+#include <mutex>
+#include <string>
+
+// Example for spdlog.h
+//
+// Create a file logger which creates new files with a specified time step and fixed file size:
+//
+// std::shared_ptr<logger> step_logger_mt(const std::string &logger_name, const filename_t &filename, unsigned seconds = 60, const
+// filename_t &tmp_ext = ".tmp", unsigned max_file_size = std::numeric_limits<unsigned>::max(), bool delete_empty_files = true, const
+// filename_t &file_header = ""); std::shared_ptr<logger> step_logger_st(const std::string &logger_name, const filename_t &filename,
+// unsigned seconds = 60, const filename_t &tmp_ext = ".tmp", unsigned max_file_size = std::numeric_limits<unsigned>::max());
+
+// Example for spdlog_impl.h
+// Create a file logger that creates new files with a specified increment
+// inline std::shared_ptr<spdlog::logger> spdlog::step_logger_mt(
+//     const std::string &logger_name, const filename_t &filename_fmt, unsigned seconds, const filename_t &tmp_ext, unsigned max_file_size,
+//     bool delete_empty_files, const filename_t &file_header)
+// {
+//     return create<spdlog::sinks::step_file_sink_mt>(logger_name, filename_fmt, seconds, tmp_ext, max_file_size, delete_empty_files,
+//     file_header);
+// }
+
+// inline std::shared_ptr<spdlog::logger> spdlog::step_logger_st(
+//     const std::string &logger_name, const filename_t &filename_fmt, unsigned seconds, const filename_t &tmp_ext, unsigned max_file_size,
+//     bool delete_empty_files, const filename_t &file_header)
+// {
+//     return create<spdlog::sinks::step_file_sink_st>(logger_name, filename_fmt, seconds, tmp_ext, max_file_size, delete_empty_files,
+//     file_header);
+// }
+
+namespace spdlog {
+namespace sinks {
+
+/*
+ * Default generator of step log file names.
+ */
+struct default_step_file_name_calculator
+{
+    // Create filename for the form filename_YYYY-MM-DD_hh-mm-ss.ext
+    static std::tuple<filename_t, filename_t> calc_filename(const filename_t &filename, const filename_t &tmp_ext)
+    {
+        std::tm tm = spdlog::details::os::localtime();
+        filename_t basename, ext;
+        std::tie(basename, ext) = details::file_helper::split_by_extenstion(filename);
+        std::conditional<std::is_same<filename_t::value_type, char>::value, fmt::MemoryWriter, fmt::WMemoryWriter>::type w;
+        w.write(SPDLOG_FILENAME_T("{}_{:04d}-{:02d}-{:02d}_{:02d}-{:02d}-{:02d}{}"), basename, tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday,
+            tm.tm_hour, tm.tm_min, tm.tm_sec, tmp_ext);
+        return std::make_tuple(w.str(), ext);
+    }
+};
+
+/*
+ * Rotating file sink based on size and a specified time step
+ */
+template<class Mutex, class FileNameCalc = default_step_file_name_calculator>
+class step_file_sink SPDLOG_FINAL : public base_sink<Mutex>
+{
+public:
+    step_file_sink(filename_t base_filename, unsigned step_seconds, filename_t tmp_ext, unsigned max_size, bool delete_empty_files,
+        filename_t file_header)
+        : _base_filename(std::move(base_filename))
+        , _tmp_ext(std::move(tmp_ext))
+        , _step_seconds(step_seconds)
+        , _max_size(max_size)
+        , _delete_empty_files(delete_empty_files)
+    {
+        if (step_seconds == 0)
+        {
+            throw spdlog_ex("step_file_sink: Invalid time step in ctor");
+        }
+
+        if (!file_header.empty())
+        {
+            pattern_formatter formatter_for_file_header("%v");
+            _file_header.raw << file_header;
+            formatter_for_file_header.format(_file_header);
+        }
+
+        if (max_size <= _file_header.formatted.size())
+        {
+            throw spdlog_ex("step_file_sink: Invalid max log size in ctor");
+        }
+
+        _tp = _next_tp();
+        std::tie(_current_filename, _ext) = FileNameCalc::calc_filename(_base_filename, _tmp_ext);
+
+        if (_tmp_ext == _ext)
+        {
+            throw spdlog_ex("step_file_sink: The temporary extension matches the specified in ctor");
+        }
+
+        _file_helper.open(_current_filename);
+        _current_size = _file_helper.size(); // expensive. called only once
+
+        if (!_current_size)
+        {
+            _current_size += _file_header.formatted.size();
+            if (_current_size)
+                _file_helper.write(_file_header);
+        }
+    }
+
+    ~step_file_sink()
+    {
+        try
+        {
+            close_current_file();
+        }
+        catch (...)
+        {
+        }
+    }
+
+protected:
+    void _sink_it(const details::log_msg &msg) override
+    {
+        auto msg_size = msg.formatted.size();
+
+        if (std::chrono::system_clock::now() >= _tp || _current_size + msg_size > _max_size)
+        {
+            filename_t new_filename;
+            std::tie(new_filename, std::ignore) = FileNameCalc::calc_filename(_base_filename, _tmp_ext);
+
+            bool change_occured = !details::file_helper::file_exists(new_filename);
+            if (change_occured)
+            {
+                close_current_file();
+
+                _current_filename = std::move(new_filename);
+
+                _file_helper.open(_current_filename);
+            }
+
+            _tp = _next_tp();
+
+            if (change_occured)
+            {
+                _current_size = _file_header.formatted.size();
+                if (_current_size)
+                    _file_helper.write(_file_header);
+            }
+        }
+
+        _current_size += msg_size;
+        _file_helper.write(msg);
+    }
+
+    void _flush() override
+    {
+        _file_helper.flush();
+    }
+
+private:
+    std::chrono::system_clock::time_point _next_tp()
+    {
+        return std::chrono::system_clock::now() + _step_seconds;
+    }
+
+    void close_current_file()
+    {
+        using details::os::filename_to_str;
+
+        // Delete empty files, if required
+        if (_delete_empty_files && _current_size <= _file_header.formatted.size())
+        {
+            if (details::os::remove(_current_filename) != 0)
+            {
+                throw spdlog_ex("step_file_sink: not remove " + filename_to_str(_current_filename), errno);
+            }
+
+            return;
+        }
+
+        filename_t target;
+        std::tie(target, std::ignore) = details::file_helper::split_by_extenstion(_current_filename);
+        target += _ext;
+
+        if (details::file_helper::file_exists(_current_filename) && details::os::rename(_current_filename, target) != 0)
+        {
+            throw spdlog_ex(
+                "step_file_sink: failed renaming " + filename_to_str(_current_filename) + " to " + filename_to_str(target), errno);
+        }
+    }
+
+    const filename_t _base_filename;
+    const filename_t _tmp_ext;
+    const std::chrono::seconds _step_seconds;
+    const unsigned _max_size;
+    const bool _delete_empty_files;
+
+    std::chrono::system_clock::time_point _tp;
+    filename_t _current_filename;
+    filename_t _ext;
+    unsigned _current_size;
+
+    details::file_helper _file_helper;
+    details::log_msg _file_header;
+};
+
+using step_file_sink_mt = step_file_sink<std::mutex>;
+using step_file_sink_st = step_file_sink<details::null_mutex>;
+
+} // namespace sinks
+} // namespace spdlog
diff --git a/lib/spdlog/details/async_log_helper.h b/lib/spdlog/details/async_log_helper.h
new file mode 100644
index 0000000..49789b9
--- /dev/null
+++ b/lib/spdlog/details/async_log_helper.h
@@ -0,0 +1,333 @@
+//
+// Copyright(c) 2015 Gabi Melman.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+//
+
+// async log helper :
+// Process logs asynchronously using a back thread.
+//
+// If the internal queue of log messages reaches its max size,
+// then the client call will block until there is more room.
+//
+
+#pragma once
+
+#include "../common.h"
+#include "../details/log_msg.h"
+#include "../details/mpmc_blocking_q.h"
+#include "../details/os.h"
+#include "../formatter.h"
+#include "../sinks/sink.h"
+
+#include <chrono>
+#include <condition_variable>
+#include <exception>
+#include <functional>
+#include <memory>
+#include <string>
+#include <thread>
+#include <utility>
+#include <vector>
+
+namespace spdlog {
+namespace details {
+
+class async_log_helper
+{
+    // Async msg to move to/from the queue
+    // Movable only. should never be copied
+    enum class async_msg_type
+    {
+        log,
+        flush,
+        terminate
+    };
+
+    struct async_msg
+    {
+        level::level_enum level;
+        log_clock::time_point time;
+        size_t thread_id;
+        std::string txt;
+        async_msg_type msg_type;
+        size_t msg_id;
+
+        async_msg() = default;
+        ~async_msg() = default;
+
+        explicit async_msg(async_msg_type m_type)
+            : level(level::info)
+            , thread_id(0)
+            , msg_type(m_type)
+            , msg_id(0)
+        {
+        }
+
+        async_msg(async_msg &&other) = default;
+        async_msg &operator=(async_msg &&other) = default;
+
+        // never copy or assign. should only be moved..
+        async_msg(const async_msg &) = delete;
+        async_msg &operator=(const async_msg &other) = delete;
+
+        // construct from log_msg
+        explicit async_msg(const details::log_msg &m)
+            : level(m.level)
+            , time(m.time)
+            , thread_id(m.thread_id)
+            , txt(m.raw.data(), m.raw.size())
+            , msg_type(async_msg_type::log)
+            , msg_id(m.msg_id)
+        {
+        }
+
+        // copy into log_msg
+        void fill_log_msg(log_msg &msg, std::string *logger_name)
+        {
+            msg.logger_name = logger_name;
+            msg.level = level;
+            msg.time = time;
+            msg.thread_id = thread_id;
+            msg.raw.clear();
+            msg.raw << txt;
+            msg.msg_id = msg_id;
+        }
+    };
+
+public:
+    using item_type = async_msg;
+    using q_type = details::mpmc_bounded_queue<item_type>;
+
+    using clock = std::chrono::steady_clock;
+
+    async_log_helper(std::string logger_name, formatter_ptr formatter, std::vector<sink_ptr> sinks, size_t queue_size,
+        const log_err_handler err_handler, const async_overflow_policy overflow_policy = async_overflow_policy::block_retry,
+        std::function<void()> worker_warmup_cb = nullptr,
+        const std::chrono::milliseconds &flush_interval_ms = std::chrono::milliseconds::zero(),
+        std::function<void()> worker_teardown_cb = nullptr);
+
+    void log(const details::log_msg &msg);
+
+    // stop logging and join the back thread
+    ~async_log_helper();
+
+    async_log_helper(const async_log_helper &) = delete;
+    async_log_helper &operator=(const async_log_helper &) = delete;
+
+    void set_formatter(formatter_ptr msg_formatter);
+
+    void flush();
+
+    void set_error_handler(spdlog::log_err_handler err_handler);
+
+private:
+    std::string _logger_name;
+    formatter_ptr _formatter;
+    std::vector<std::shared_ptr<sinks::sink>> _sinks;
+
+    // queue of messages to log
+    q_type _q;
+
+    log_err_handler _err_handler;
+
+    std::chrono::time_point<log_clock> _last_flush;
+
+    // overflow policy
+    const async_overflow_policy _overflow_policy;
+
+    // worker thread warmup callback - one can set thread priority, affinity, etc
+    const std::function<void()> _worker_warmup_cb;
+
+    // auto periodic sink flush parameter
+    const std::chrono::milliseconds _flush_interval_ms;
+
+    // worker thread teardown callback
+    const std::function<void()> _worker_teardown_cb;
+
+    std::mutex null_mutex_;
+    // null_mutex null_mutex_;
+    std::condition_variable_any not_empty_cv_;
+    std::condition_variable_any not_full_cv_;
+
+    // worker thread
+    std::thread _worker_thread;
+
+    void enqueue_msg(async_msg &&new_msg, async_overflow_policy policy);
+
+    // worker thread main loop
+    void worker_loop();
+
+    // dequeue next message from the queue and process it.
+    // return false if termination of the queue is required
+    bool process_next_msg();
+
+    void handle_flush_interval();
+
+    void flush_sinks();
+};
+} // namespace details
+} // namespace spdlog
+
+///////////////////////////////////////////////////////////////////////////////
+// async_sink class implementation
+///////////////////////////////////////////////////////////////////////////////
+inline spdlog::details::async_log_helper::async_log_helper(std::string logger_name, formatter_ptr formatter, std::vector<sink_ptr> sinks,
+    size_t queue_size, log_err_handler err_handler, const async_overflow_policy overflow_policy, std::function<void()> worker_warmup_cb,
+    const std::chrono::milliseconds &flush_interval_ms, std::function<void()> worker_teardown_cb)
+    : _logger_name(std::move(logger_name))
+    , _formatter(std::move(formatter))
+    , _sinks(std::move(sinks))
+    , _q(queue_size)
+    , _err_handler(std::move(err_handler))
+    , _last_flush(os::now())
+    , _overflow_policy(overflow_policy)
+    , _worker_warmup_cb(std::move(worker_warmup_cb))
+    , _flush_interval_ms(flush_interval_ms)
+    , _worker_teardown_cb(std::move(worker_teardown_cb))
+{
+    _worker_thread = std::thread(&async_log_helper::worker_loop, this);
+}
+
+// send to the worker thread terminate message, and join it.
+inline spdlog::details::async_log_helper::~async_log_helper()
+{
+    try
+    {
+        enqueue_msg(async_msg(async_msg_type::terminate), async_overflow_policy::block_retry);
+        _worker_thread.join();
+    }
+    catch (...) // don't crash in destructor
+    {
+    }
+}
+
+// try to push and block until succeeded (if the policy is not to discard when the queue is full)
+inline void spdlog::details::async_log_helper::log(const details::log_msg &msg)
+{
+    enqueue_msg(async_msg(msg), _overflow_policy);
+}
+
+inline void spdlog::details::async_log_helper::enqueue_msg(details::async_log_helper::async_msg &&new_msg, async_overflow_policy policy)
+{
+
+    // block until succeeded pushing to the queue
+    if (policy == async_overflow_policy::block_retry)
+    {
+        _q.enqueue(std::move(new_msg));
+    }
+    else
+    {
+        _q.enqueue_nowait(std::move(new_msg));
+    }
+}
+
+// optionally wait for the queue be empty and request flush from the sinks
+inline void spdlog::details::async_log_helper::flush()
+{
+    enqueue_msg(async_msg(async_msg_type::flush), _overflow_policy);
+}
+
+inline void spdlog::details::async_log_helper::worker_loop()
+{
+    if (_worker_warmup_cb)
+    {
+        _worker_warmup_cb();
+    }
+    auto active = true;
+    while (active)
+    {
+        try
+        {
+            active = process_next_msg();
+        }
+        SPDLOG_CATCH_AND_HANDLE
+    }
+    if (_worker_teardown_cb)
+    {
+        _worker_teardown_cb();
+    }
+}
+
+// process next message in the queue
+// return true if this thread should still be active (while no terminate msg was received)
+inline bool spdlog::details::async_log_helper::process_next_msg()
+{
+    async_msg incoming_async_msg;
+    bool dequeued = _q.dequeue_for(incoming_async_msg, std::chrono::seconds(2));
+    if (!dequeued)
+    {
+        handle_flush_interval();
+        return true;
+    }
+
+    switch (incoming_async_msg.msg_type)
+    {
+    case async_msg_type::flush:
+        flush_sinks();
+        return true;
+
+    case async_msg_type::terminate:
+        flush_sinks();
+        return false;
+
+    default:
+        log_msg incoming_log_msg;
+        incoming_async_msg.fill_log_msg(incoming_log_msg, &_logger_name);
+        _formatter->format(incoming_log_msg);
+        for (auto &s : _sinks)
+        {
+            if (s->should_log(incoming_log_msg.level))
+            {
+                try
+                {
+                    s->log(incoming_log_msg);
+                }
+                SPDLOG_CATCH_AND_HANDLE
+            }
+        }
+        handle_flush_interval();
+        return true;
+    }
+    assert(false);
+    return true; // should not be reached
+}
+
+inline void spdlog::details::async_log_helper::set_formatter(formatter_ptr msg_formatter)
+{
+    _formatter = std::move(msg_formatter);
+}
+
+inline void spdlog::details::async_log_helper::set_error_handler(spdlog::log_err_handler err_handler)
+{
+    _err_handler = std::move(err_handler);
+}
+
+// flush all sinks if _flush_interval_ms has expired.
+inline void spdlog::details::async_log_helper::handle_flush_interval()
+{
+    if (_flush_interval_ms == std::chrono::milliseconds::zero())
+    {
+        return;
+    }
+    auto delta = details::os::now() - _last_flush;
+    ;
+    if (delta >= _flush_interval_ms)
+    {
+        flush_sinks();
+    }
+}
+
+// flush all sinks if _flush_interval_ms has expired. only called if queue is empty
+inline void spdlog::details::async_log_helper::flush_sinks()
+{
+
+    for (auto &s : _sinks)
+    {
+        try
+        {
+            s->flush();
+        }
+        SPDLOG_CATCH_AND_HANDLE
+    }
+    _last_flush = os::now();
+}
diff --git a/lib/spdlog/details/async_logger_impl.h b/lib/spdlog/details/async_logger_impl.h
new file mode 100644
index 0000000..33ab4b9
--- /dev/null
+++ b/lib/spdlog/details/async_logger_impl.h
@@ -0,0 +1,95 @@
+//
+// Copyright(c) 2015 Gabi Melman.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+//
+
+#pragma once
+
+// Async Logger implementation
+// Use an async_sink (queue per logger) to perform the logging in a worker thread
+
+#include "../async_logger.h"
+#include "../details/async_log_helper.h"
+
+#include <chrono>
+#include <functional>
+#include <memory>
+#include <string>
+
+template<class It>
+inline spdlog::async_logger::async_logger(const std::string &logger_name, const It &begin, const It &end, size_t queue_size,
+    const async_overflow_policy overflow_policy, const std::function<void()> &worker_warmup_cb,
+    const std::chrono::milliseconds &flush_interval_ms, const std::function<void()> &worker_teardown_cb)
+    : logger(logger_name, begin, end)
+    , _async_log_helper(new details::async_log_helper(logger_name, _formatter, _sinks, queue_size, _err_handler, overflow_policy,
+          worker_warmup_cb, flush_interval_ms, worker_teardown_cb))
+{
+}
+
+inline spdlog::async_logger::async_logger(const std::string &logger_name, sinks_init_list sinks_list, size_t queue_size,
+    const async_overflow_policy overflow_policy, const std::function<void()> &worker_warmup_cb,
+    const std::chrono::milliseconds &flush_interval_ms, const std::function<void()> &worker_teardown_cb)
+    : async_logger(logger_name, sinks_list.begin(), sinks_list.end(), queue_size, overflow_policy, worker_warmup_cb, flush_interval_ms,
+          worker_teardown_cb)
+{
+}
+
+inline spdlog::async_logger::async_logger(const std::string &logger_name, sink_ptr single_sink, size_t queue_size,
+    const async_overflow_policy overflow_policy, const std::function<void()> &worker_warmup_cb,
+    const std::chrono::milliseconds &flush_interval_ms, const std::function<void()> &worker_teardown_cb)
+    : async_logger(
+          logger_name, {std::move(single_sink)}, queue_size, overflow_policy, worker_warmup_cb, flush_interval_ms, worker_teardown_cb)
+{
+}
+
+inline void spdlog::async_logger::flush()
+{
+    _async_log_helper->flush();
+}
+
+// Error handler
+inline void spdlog::async_logger::set_error_handler(spdlog::log_err_handler err_handler)
+{
+    _err_handler = err_handler;
+    _async_log_helper->set_error_handler(err_handler);
+}
+inline spdlog::log_err_handler spdlog::async_logger::error_handler()
+{
+    return _err_handler;
+}
+
+inline void spdlog::async_logger::_set_formatter(spdlog::formatter_ptr msg_formatter)
+{
+    _formatter = msg_formatter;
+    _async_log_helper->set_formatter(_formatter);
+}
+
+inline void spdlog::async_logger::_set_pattern(const std::string &pattern, pattern_time_type pattern_time)
+{
+    _formatter = std::make_shared<pattern_formatter>(pattern, pattern_time);
+    _async_log_helper->set_formatter(_formatter);
+}
+
+inline void spdlog::async_logger::_sink_it(details::log_msg &msg)
+{
+    try
+    {
+#if defined(SPDLOG_ENABLE_MESSAGE_COUNTER)
+        _incr_msg_counter(msg);
+#endif
+        _async_log_helper->log(msg);
+        if (_should_flush_on(msg))
+        {
+            _async_log_helper->flush(); // do async flush
+        }
+    }
+    catch (const std::exception &ex)
+    {
+        _err_handler(ex.what());
+    }
+    catch (...)
+    {
+        _err_handler("Unknown exception in logger " + _name);
+        throw;
+    }
+}
diff --git a/lib/spdlog/details/file_helper.h b/lib/spdlog/details/file_helper.h
new file mode 100644
index 0000000..d30a79b
--- /dev/null
+++ b/lib/spdlog/details/file_helper.h
@@ -0,0 +1,151 @@
+//
+// Copyright(c) 2015 Gabi Melman.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+//
+
+#pragma once
+
+// Helper class for file sink
+// When failing to open a file, retry several times(5) with small delay between the tries(10 ms)
+// Throw spdlog_ex exception on errors
+
+#include "../details/log_msg.h"
+#include "../details/os.h"
+
+#include <cerrno>
+#include <chrono>
+#include <cstdio>
+#include <string>
+#include <thread>
+#include <tuple>
+
+namespace spdlog {
+namespace details {
+
+class file_helper
+{
+
+public:
+    const int open_tries = 5;
+    const int open_interval = 10;
+
+    explicit file_helper() = default;
+
+    file_helper(const file_helper &) = delete;
+    file_helper &operator=(const file_helper &) = delete;
+
+    ~file_helper()
+    {
+        close();
+    }
+
+    void open(const filename_t &fname, bool truncate = false)
+    {
+        close();
+        auto *mode = truncate ? SPDLOG_FILENAME_T("wb") : SPDLOG_FILENAME_T("ab");
+        _filename = fname;
+        for (int tries = 0; tries < open_tries; ++tries)
+        {
+            if (!os::fopen_s(&_fd, fname, mode))
+            {
+                return;
+            }
+
+            details::os::sleep_for_millis(open_interval);
+        }
+
+        throw spdlog_ex("Failed opening file " + os::filename_to_str(_filename) + " for writing", errno);
+    }
+
+    void reopen(bool truncate)
+    {
+        if (_filename.empty())
+        {
+            throw spdlog_ex("Failed re opening file - was not opened before");
+        }
+        open(_filename, truncate);
+    }
+
+    void flush()
+    {
+        std::fflush(_fd);
+    }
+
+    void close()
+    {
+        if (_fd != nullptr)
+        {
+            std::fclose(_fd);
+            _fd = nullptr;
+        }
+    }
+
+    void write(const log_msg &msg)
+    {
+        size_t msg_size = msg.formatted.size();
+        auto data = msg.formatted.data();
+        if (std::fwrite(data, 1, msg_size, _fd) != msg_size)
+        {
+            throw spdlog_ex("Failed writing to file " + os::filename_to_str(_filename), errno);
+        }
+    }
+
+    size_t size() const
+    {
+        if (_fd == nullptr)
+        {
+            throw spdlog_ex("Cannot use size() on closed file " + os::filename_to_str(_filename));
+        }
+        return os::filesize(_fd);
+    }
+
+    const filename_t &filename() const
+    {
+        return _filename;
+    }
+
+    static bool file_exists(const filename_t &fname)
+    {
+        return os::file_exists(fname);
+    }
+
+    //
+    // return file path and its extension:
+    //
+    // "mylog.txt" => ("mylog", ".txt")
+    // "mylog" => ("mylog", "")
+    // "mylog." => ("mylog.", "")
+    // "/dir1/dir2/mylog.txt" => ("/dir1/dir2/mylog", ".txt")
+    //
+    // the starting dot in filenames is ignored (hidden files):
+    //
+    // ".mylog" => (".mylog". "")
+    // "my_folder/.mylog" => ("my_folder/.mylog", "")
+    // "my_folder/.mylog.txt" => ("my_folder/.mylog", ".txt")
+    static std::tuple<filename_t, filename_t> split_by_extenstion(const spdlog::filename_t &fname)
+    {
+        auto ext_index = fname.rfind('.');
+
+        // no valid extension found - return whole path and empty string as extension
+        if (ext_index == filename_t::npos || ext_index == 0 || ext_index == fname.size() - 1)
+        {
+            return std::make_tuple(fname, spdlog::filename_t());
+        }
+
+        // treat casese like "/etc/rc.d/somelogfile or "/abc/.hiddenfile"
+        auto folder_index = fname.rfind(details::os::folder_sep);
+        if (folder_index != fname.npos && folder_index >= ext_index - 1)
+        {
+            return std::make_tuple(fname, spdlog::filename_t());
+        }
+
+        // finally - return a valid base and extension tuple
+        return std::make_tuple(fname.substr(0, ext_index), fname.substr(ext_index));
+    }
+
+private:
+    FILE *_fd{nullptr};
+    filename_t _filename;
+};
+} // namespace details
+} // namespace spdlog
diff --git a/lib/spdlog/details/log_msg.h b/lib/spdlog/details/log_msg.h
new file mode 100644
index 0000000..1d079aa
--- /dev/null
+++ b/lib/spdlog/details/log_msg.h
@@ -0,0 +1,48 @@
+//
+// Copyright(c) 2015 Gabi Melman.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+//
+
+#pragma once
+
+#include "../common.h"
+#include "../details/os.h"
+
+#include <string>
+#include <utility>
+
+namespace spdlog {
+namespace details {
+struct log_msg
+{
+    log_msg() = default;
+    log_msg(const std::string *loggers_name, level::level_enum lvl)
+        : logger_name(loggers_name)
+        , level(lvl)
+    {
+#ifndef SPDLOG_NO_DATETIME
+        time = os::now();
+#endif
+
+#ifndef SPDLOG_NO_THREAD_ID
+        thread_id = os::thread_id();
+#endif
+    }
+
+    log_msg(const log_msg &other) = delete;
+    log_msg &operator=(log_msg &&other) = delete;
+    log_msg(log_msg &&other) = delete;
+
+    const std::string *logger_name{nullptr};
+    level::level_enum level;
+    log_clock::time_point time;
+    size_t thread_id;
+    fmt::MemoryWriter raw;
+    fmt::MemoryWriter formatted;
+    size_t msg_id{0};
+    // wrap this range with color codes
+    size_t color_range_start{0};
+    size_t color_range_end{0};
+};
+} // namespace details
+} // namespace spdlog
diff --git a/lib/spdlog/details/logger_impl.h b/lib/spdlog/details/logger_impl.h
new file mode 100644
index 0000000..084ecdd
--- /dev/null
+++ b/lib/spdlog/details/logger_impl.h
@@ -0,0 +1,348 @@
+//
+// Copyright(c) 2015 Gabi Melman.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+//
+
+#pragma once
+
+#include "../logger.h"
+
+#include <memory>
+#include <string>
+
+// create logger with given name, sinks and the default pattern formatter
+// all other ctors will call this one
+template<class It>
+inline spdlog::logger::logger(std::string logger_name, const It &begin, const It &end)
+    : _name(std::move(logger_name))
+    , _sinks(begin, end)
+    , _formatter(std::make_shared<pattern_formatter>("%+"))
+    , _level(level::info)
+    , _flush_level(level::off)
+    , _last_err_time(0)
+    , _msg_counter(1) // message counter will start from 1. 0-message id will be reserved for controll messages
+{
+    _err_handler = [this](const std::string &msg) { this->_default_err_handler(msg); };
+}
+
+// ctor with sinks as init list
+inline spdlog::logger::logger(const std::string &logger_name, sinks_init_list sinks_list)
+    : logger(logger_name, sinks_list.begin(), sinks_list.end())
+{
+}
+
+// ctor with single sink
+inline spdlog::logger::logger(const std::string &logger_name, spdlog::sink_ptr single_sink)
+    : logger(logger_name, {std::move(single_sink)})
+{
+}
+
+inline spdlog::logger::~logger() = default;
+
+inline void spdlog::logger::set_formatter(spdlog::formatter_ptr msg_formatter)
+{
+    _set_formatter(std::move(msg_formatter));
+}
+
+inline void spdlog::logger::set_pattern(const std::string &pattern, pattern_time_type pattern_time)
+{
+    _set_pattern(pattern, pattern_time);
+}
+
+template<typename... Args>
+inline void spdlog::logger::log(level::level_enum lvl, const char *fmt, const Args &... args)
+{
+    if (!should_log(lvl))
+    {
+        return;
+    }
+
+    try
+    {
+        details::log_msg log_msg(&_name, lvl);
+
+#if defined(SPDLOG_FMT_PRINTF)
+        fmt::printf(log_msg.raw, fmt, args...);
+#else
+        log_msg.raw.write(fmt, args...);
+#endif
+        _sink_it(log_msg);
+    }
+    SPDLOG_CATCH_AND_HANDLE
+}
+
+template<typename... Args>
+inline void spdlog::logger::log(level::level_enum lvl, const char *msg)
+{
+    if (!should_log(lvl))
+    {
+        return;
+    }
+    try
+    {
+        details::log_msg log_msg(&_name, lvl);
+        log_msg.raw << msg;
+        _sink_it(log_msg);
+    }
+    SPDLOG_CATCH_AND_HANDLE
+}
+
+template<typename T>
+inline void spdlog::logger::log(level::level_enum lvl, const T &msg)
+{
+    if (!should_log(lvl))
+    {
+        return;
+    }
+    try
+    {
+        details::log_msg log_msg(&_name, lvl);
+        log_msg.raw << msg;
+        _sink_it(log_msg);
+    }
+    SPDLOG_CATCH_AND_HANDLE
+}
+
+template<typename Arg1, typename... Args>
+inline void spdlog::logger::trace(const char *fmt, const Arg1 &arg1, const Args &... args)
+{
+    log(level::trace, fmt, arg1, args...);
+}
+
+template<typename Arg1, typename... Args>
+inline void spdlog::logger::debug(const char *fmt, const Arg1 &arg1, const Args &... args)
+{
+    log(level::debug, fmt, arg1, args...);
+}
+
+template<typename Arg1, typename... Args>
+inline void spdlog::logger::info(const char *fmt, const Arg1 &arg1, const Args &... args)
+{
+    log(level::info, fmt, arg1, args...);
+}
+
+template<typename Arg1, typename... Args>
+inline void spdlog::logger::warn(const char *fmt, const Arg1 &arg1, const Args &... args)
+{
+    log(level::warn, fmt, arg1, args...);
+}
+
+template<typename Arg1, typename... Args>
+inline void spdlog::logger::error(const char *fmt, const Arg1 &arg1, const Args &... args)
+{
+    log(level::err, fmt, arg1, args...);
+}
+
+template<typename Arg1, typename... Args>
+inline void spdlog::logger::critical(const char *fmt, const Arg1 &arg1, const Args &... args)
+{
+    log(level::critical, fmt, arg1, args...);
+}
+
+template<typename T>
+inline void spdlog::logger::trace(const T &msg)
+{
+    log(level::trace, msg);
+}
+
+template<typename T>
+inline void spdlog::logger::debug(const T &msg)
+{
+    log(level::debug, msg);
+}
+
+template<typename T>
+inline void spdlog::logger::info(const T &msg)
+{
+    log(level::info, msg);
+}
+
+template<typename T>
+inline void spdlog::logger::warn(const T &msg)
+{
+    log(level::warn, msg);
+}
+
+template<typename T>
+inline void spdlog::logger::error(const T &msg)
+{
+    log(level::err, msg);
+}
+
+template<typename T>
+inline void spdlog::logger::critical(const T &msg)
+{
+    log(level::critical, msg);
+}
+
+#ifdef SPDLOG_WCHAR_TO_UTF8_SUPPORT
+#include <codecvt>
+#include <locale>
+
+template<typename... Args>
+inline void spdlog::logger::log(level::level_enum lvl, const wchar_t *msg)
+{
+    std::wstring_convert<std::codecvt_utf8<wchar_t>> conv;
+
+    log(lvl, conv.to_bytes(msg));
+}
+
+template<typename... Args>
+inline void spdlog::logger::log(level::level_enum lvl, const wchar_t *fmt, const Args &... args)
+{
+    fmt::WMemoryWriter wWriter;
+
+    wWriter.write(fmt, args...);
+    log(lvl, wWriter.c_str());
+}
+
+template<typename... Args>
+inline void spdlog::logger::trace(const wchar_t *fmt, const Args &... args)
+{
+    log(level::trace, fmt, args...);
+}
+
+template<typename... Args>
+inline void spdlog::logger::debug(const wchar_t *fmt, const Args &... args)
+{
+    log(level::debug, fmt, args...);
+}
+
+template<typename... Args>
+inline void spdlog::logger::info(const wchar_t *fmt, const Args &... args)
+{
+    log(level::info, fmt, args...);
+}
+
+template<typename... Args>
+inline void spdlog::logger::warn(const wchar_t *fmt, const Args &... args)
+{
+    log(level::warn, fmt, args...);
+}
+
+template<typename... Args>
+inline void spdlog::logger::error(const wchar_t *fmt, const Args &... args)
+{
+    log(level::err, fmt, args...);
+}
+
+template<typename... Args>
+inline void spdlog::logger::critical(const wchar_t *fmt, const Args &... args)
+{
+    log(level::critical, fmt, args...);
+}
+
+#endif // SPDLOG_WCHAR_TO_UTF8_SUPPORT
+
+//
+// name and level
+//
+inline const std::string &spdlog::logger::name() const
+{
+    return _name;
+}
+
+inline void spdlog::logger::set_level(spdlog::level::level_enum log_level)
+{
+    _level.store(log_level);
+}
+
+inline void spdlog::logger::set_error_handler(spdlog::log_err_handler err_handler)
+{
+    _err_handler = std::move(err_handler);
+}
+
+inline spdlog::log_err_handler spdlog::logger::error_handler()
+{
+    return _err_handler;
+}
+
+inline void spdlog::logger::flush_on(level::level_enum log_level)
+{
+    _flush_level.store(log_level);
+}
+
+inline spdlog::level::level_enum spdlog::logger::level() const
+{
+    return static_cast<spdlog::level::level_enum>(_level.load(std::memory_order_relaxed));
+}
+
+inline bool spdlog::logger::should_log(spdlog::level::level_enum msg_level) const
+{
+    return msg_level >= _level.load(std::memory_order_relaxed);
+}
+
+//
+// protected virtual called at end of each user log call (if enabled) by the line_logger
+//
+inline void spdlog::logger::_sink_it(details::log_msg &msg)
+{
+#if defined(SPDLOG_ENABLE_MESSAGE_COUNTER)
+    _incr_msg_counter(msg);
+#endif
+    _formatter->format(msg);
+    for (auto &sink : _sinks)
+    {
+        if (sink->should_log(msg.level))
+        {
+            sink->log(msg);
+        }
+    }
+
+    if (_should_flush_on(msg))
+    {
+        flush();
+    }
+}
+
+inline void spdlog::logger::_set_pattern(const std::string &pattern, pattern_time_type pattern_time)
+{
+    _formatter = std::make_shared<pattern_formatter>(pattern, pattern_time);
+}
+
+inline void spdlog::logger::_set_formatter(formatter_ptr msg_formatter)
+{
+    _formatter = std::move(msg_formatter);
+}
+
+inline void spdlog::logger::flush()
+{
+    try
+    {
+        for (auto &sink : _sinks)
+        {
+            sink->flush();
+        }
+    }
+    SPDLOG_CATCH_AND_HANDLE
+}
+
+inline void spdlog::logger::_default_err_handler(const std::string &msg)
+{
+    auto now = time(nullptr);
+    if (now - _last_err_time < 60)
+    {
+        return;
+    }
+    _last_err_time = now;
+    auto tm_time = details::os::localtime(now);
+    char date_buf[100];
+    std::strftime(date_buf, sizeof(date_buf), "%Y-%m-%d %H:%M:%S", &tm_time);
+    fmt::print(stderr, "[*** LOG ERROR ***] [{}] [{}] {}\n", date_buf, name(), msg);
+}
+
+inline bool spdlog::logger::_should_flush_on(const details::log_msg &msg)
+{
+    const auto flush_level = _flush_level.load(std::memory_order_relaxed);
+    return (msg.level >= flush_level) && (msg.level != level::off);
+}
+
+inline void spdlog::logger::_incr_msg_counter(details::log_msg &msg)
+{
+    msg.msg_id = _msg_counter.fetch_add(1, std::memory_order_relaxed);
+}
+
+inline const std::vector<spdlog::sink_ptr> &spdlog::logger::sinks() const
+{
+    return _sinks;
+}
diff --git a/lib/spdlog/details/mpmc_blocking_q.h b/lib/spdlog/details/mpmc_blocking_q.h
new file mode 100644
index 0000000..d4a8a41
--- /dev/null
+++ b/lib/spdlog/details/mpmc_blocking_q.h
@@ -0,0 +1,84 @@
+#pragma once
+
+//
+// Copyright(c) 2018 Gabi Melman.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+//
+
+// async log helper :
+// multi producer-multi consumer blocking queue
+// enqueue(..) - will block until room found to put the new message
+// enqueue_nowait(..) - will return immediatly with false if no room left in the queue
+// dequeue_for(..) - will block until the queue is not empty or timeout passed
+
+#include <condition_variable>
+#include <mutex>
+#include <queue>
+
+namespace spdlog {
+namespace details {
+
+template<typename T>
+class mpmc_bounded_queue
+{
+public:
+    using item_type = T;
+    explicit mpmc_bounded_queue(size_t max_items)
+        : max_items_(max_items)
+    {
+    }
+
+    // try to enqueue and block if no room left
+    void enqueue(T &&item)
+    {
+        {
+            std::unique_lock<std::mutex> lock(queue_mutex_);
+            pop_cv_.wait(lock, [this] { return this->q_.size() < this->max_items_; });
+            q_.push(std::move(item));
+        }
+        push_cv_.notify_one();
+    }
+
+    // try to enqueue and return immdeialty false if no room left
+    bool enqueue_nowait(T &&item)
+    {
+        {
+            std::unique_lock<std::mutex> lock(queue_mutex_);
+            if (q_.size() == this->max_items_)
+            {
+                return false;
+            }
+            q_.push(std::forward<T>(item));
+        }
+        push_cv_.notify_one();
+        return true;
+    }
+
+    // try to dequeue item. if no item found. wait upto timeout and try again
+    // Return true, if succeeded dequeue item, false otherwise
+    bool dequeue_for(T &popped_item, std::chrono::milliseconds wait_duration)
+    {
+        {
+            std::unique_lock<std::mutex> lock(queue_mutex_);
+            if (!push_cv_.wait_for(lock, wait_duration, [this] { return this->q_.size() > 0; }))
+            {
+                return false;
+            }
+
+            popped_item = std::move(q_.front());
+            q_.pop();
+        }
+        pop_cv_.notify_one();
+        return true;
+    }
+
+private:
+    size_t max_items_;
+    std::mutex queue_mutex_;
+    std::condition_variable push_cv_;
+    std::condition_variable pop_cv_;
+
+    std::queue<T> q_;
+};
+} // namespace details
+} // namespace spdlog
diff --git a/lib/spdlog/details/null_mutex.h b/lib/spdlog/details/null_mutex.h
new file mode 100644
index 0000000..3f495bd
--- /dev/null
+++ b/lib/spdlog/details/null_mutex.h
@@ -0,0 +1,45 @@
+//
+// Copyright(c) 2015 Gabi Melman.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+//
+
+#pragma once
+
+#include <atomic>
+// null, no cost dummy "mutex" and dummy "atomic" int
+
+namespace spdlog {
+namespace details {
+struct null_mutex
+{
+    void lock() {}
+    void unlock() {}
+    bool try_lock()
+    {
+        return true;
+    }
+};
+
+struct null_atomic_int
+{
+    int value;
+    null_atomic_int() = default;
+
+    explicit null_atomic_int(int val)
+        : value(val)
+    {
+    }
+
+    int load(std::memory_order) const
+    {
+        return value;
+    }
+
+    void store(int val)
+    {
+        value = val;
+    }
+};
+
+} // namespace details
+} // namespace spdlog
diff --git a/lib/spdlog/details/os.h b/lib/spdlog/details/os.h
new file mode 100644
index 0000000..28eb53c
--- /dev/null
+++ b/lib/spdlog/details/os.h
@@ -0,0 +1,431 @@
+//
+// Copyright(c) 2015 Gabi Melman.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+//
+#pragma once
+
+#include "../common.h"
+
+#include <algorithm>
+#include <chrono>
+#include <cstdio>
+#include <cstdlib>
+#include <cstring>
+#include <ctime>
+#include <functional>
+#include <string>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <thread>
+
+#ifdef _WIN32
+
+#ifndef NOMINMAX
+#define NOMINMAX // prevent windows redefining min/max
+#endif
+
+#ifndef WIN32_LEAN_AND_MEAN
+#define WIN32_LEAN_AND_MEAN
+#endif
+#include <io.h>      // _get_osfhandle and _isatty support
+#include <process.h> //  _get_pid support
+#include <windows.h>
+
+#ifdef __MINGW32__
+#include <share.h>
+#endif
+
+#else // unix
+
+#include <fcntl.h>
+#include <unistd.h>
+
+#ifdef __linux__
+#include <sys/syscall.h> //Use gettid() syscall under linux to get thread id
+
+#elif __FreeBSD__
+#include <sys/thr.h> //Use thr_self() syscall under FreeBSD to get thread id
+#endif
+
+#endif // unix
+
+#ifndef __has_feature      // Clang - feature checking macros.
+#define __has_feature(x) 0 // Compatibility with non-clang compilers.
+#endif
+
+namespace spdlog {
+namespace details {
+namespace os {
+
+inline spdlog::log_clock::time_point now()
+{
+
+#if defined __linux__ && defined SPDLOG_CLOCK_COARSE
+    timespec ts;
+    ::clock_gettime(CLOCK_REALTIME_COARSE, &ts);
+    return std::chrono::time_point<log_clock, typename log_clock::duration>(
+        std::chrono::duration_cast<typename log_clock::duration>(std::chrono::seconds(ts.tv_sec) + std::chrono::nanoseconds(ts.tv_nsec)));
+
+#else
+    return log_clock::now();
+#endif
+}
+inline std::tm localtime(const std::time_t &time_tt)
+{
+
+#ifdef _WIN32
+    std::tm tm;
+    localtime_s(&tm, &time_tt);
+#else
+    std::tm tm;
+    localtime_r(&time_tt, &tm);
+#endif
+    return tm;
+}
+
+inline std::tm localtime()
+{
+    std::time_t now_t = time(nullptr);
+    return localtime(now_t);
+}
+
+inline std::tm gmtime(const std::time_t &time_tt)
+{
+
+#ifdef _WIN32
+    std::tm tm;
+    gmtime_s(&tm, &time_tt);
+#else
+    std::tm tm;
+    gmtime_r(&time_tt, &tm);
+#endif
+    return tm;
+}
+
+inline std::tm gmtime()
+{
+    std::time_t now_t = time(nullptr);
+    return gmtime(now_t);
+}
+inline bool operator==(const std::tm &tm1, const std::tm &tm2)
+{
+    return (tm1.tm_sec == tm2.tm_sec && tm1.tm_min == tm2.tm_min && tm1.tm_hour == tm2.tm_hour && tm1.tm_mday == tm2.tm_mday &&
+            tm1.tm_mon == tm2.tm_mon && tm1.tm_year == tm2.tm_year && tm1.tm_isdst == tm2.tm_isdst);
+}
+
+inline bool operator!=(const std::tm &tm1, const std::tm &tm2)
+{
+    return !(tm1 == tm2);
+}
+
+// eol definition
+#if !defined(SPDLOG_EOL)
+#ifdef _WIN32
+#define SPDLOG_EOL "\r\n"
+#else
+#define SPDLOG_EOL "\n"
+#endif
+#endif
+
+SPDLOG_CONSTEXPR static const char *default_eol = SPDLOG_EOL;
+
+// folder separator
+#ifdef _WIN32
+SPDLOG_CONSTEXPR static const char folder_sep = '\\';
+#else
+SPDLOG_CONSTEXPR static const char folder_sep = '/';
+#endif
+
+inline void prevent_child_fd(FILE *f)
+{
+
+#ifdef _WIN32
+#if !defined(__cplusplus_winrt)
+    auto file_handle = (HANDLE)_get_osfhandle(_fileno(f));
+    if (!::SetHandleInformation(file_handle, HANDLE_FLAG_INHERIT, 0))
+        throw spdlog_ex("SetHandleInformation failed", errno);
+#endif
+#else
+    auto fd = fileno(f);
+    if (fcntl(fd, F_SETFD, FD_CLOEXEC) == -1)
+    {
+        throw spdlog_ex("fcntl with FD_CLOEXEC failed", errno);
+    }
+#endif
+}
+
+// fopen_s on non windows for writing
+inline bool fopen_s(FILE **fp, const filename_t &filename, const filename_t &mode)
+{
+#ifdef _WIN32
+#ifdef SPDLOG_WCHAR_FILENAMES
+    *fp = _wfsopen((filename.c_str()), mode.c_str(), _SH_DENYWR);
+#else
+    *fp = _fsopen((filename.c_str()), mode.c_str(), _SH_DENYWR);
+#endif
+#else // unix
+    *fp = fopen((filename.c_str()), mode.c_str());
+#endif
+
+#ifdef SPDLOG_PREVENT_CHILD_FD
+    if (*fp != nullptr)
+    {
+        prevent_child_fd(*fp);
+    }
+#endif
+    return *fp == nullptr;
+}
+
+inline int remove(const filename_t &filename)
+{
+#if defined(_WIN32) && defined(SPDLOG_WCHAR_FILENAMES)
+    return _wremove(filename.c_str());
+#else
+    return std::remove(filename.c_str());
+#endif
+}
+
+inline int rename(const filename_t &filename1, const filename_t &filename2)
+{
+#if defined(_WIN32) && defined(SPDLOG_WCHAR_FILENAMES)
+    return _wrename(filename1.c_str(), filename2.c_str());
+#else
+    return std::rename(filename1.c_str(), filename2.c_str());
+#endif
+}
+
+// Return if file exists
+inline bool file_exists(const filename_t &filename)
+{
+#ifdef _WIN32
+#ifdef SPDLOG_WCHAR_FILENAMES
+    auto attribs = GetFileAttributesW(filename.c_str());
+#else
+    auto attribs = GetFileAttributesA(filename.c_str());
+#endif
+    return (attribs != INVALID_FILE_ATTRIBUTES && !(attribs & FILE_ATTRIBUTE_DIRECTORY));
+#else // common linux/unix all have the stat system call
+    struct stat buffer;
+    return (stat(filename.c_str(), &buffer) == 0);
+#endif
+}
+
+// Return file size according to open FILE* object
+inline size_t filesize(FILE *f)
+{
+    if (f == nullptr)
+    {
+        throw spdlog_ex("Failed getting file size. fd is null");
+    }
+#if defined(_WIN32) && !defined(__CYGWIN__)
+    int fd = _fileno(f);
+#if _WIN64 // 64 bits
+    struct _stat64 st;
+    if (_fstat64(fd, &st) == 0)
+    {
+        return st.st_size;
+    }
+
+#else // windows 32 bits
+    long ret = _filelength(fd);
+    if (ret >= 0)
+    {
+        return static_cast<size_t>(ret);
+    }
+#endif
+
+#else // unix
+    int fd = fileno(f);
+    // 64 bits(but not in osx or cygwin, where fstat64 is deprecated)
+#if !defined(__FreeBSD__) && !defined(__APPLE__) && (defined(__x86_64__) || defined(__ppc64__)) && !defined(__CYGWIN__)
+    struct stat64 st;
+    if (fstat64(fd, &st) == 0)
+    {
+        return static_cast<size_t>(st.st_size);
+    }
+#else // unix 32 bits or cygwin
+    struct stat st;
+
+    if (fstat(fd, &st) == 0)
+    {
+        return static_cast<size_t>(st.st_size);
+    }
+#endif
+#endif
+    throw spdlog_ex("Failed getting file size from fd", errno);
+}
+
+// Return utc offset in minutes or throw spdlog_ex on failure
+inline int utc_minutes_offset(const std::tm &tm = details::os::localtime())
+{
+
+#ifdef _WIN32
+#if _WIN32_WINNT < _WIN32_WINNT_WS08
+    TIME_ZONE_INFORMATION tzinfo;
+    auto rv = GetTimeZoneInformation(&tzinfo);
+#else
+    DYNAMIC_TIME_ZONE_INFORMATION tzinfo;
+    auto rv = GetDynamicTimeZoneInformation(&tzinfo);
+#endif
+    if (rv == TIME_ZONE_ID_INVALID)
+        throw spdlog::spdlog_ex("Failed getting timezone info. ", errno);
+
+    int offset = -tzinfo.Bias;
+    if (tm.tm_isdst)
+    {
+        offset -= tzinfo.DaylightBias;
+    }
+    else
+    {
+        offset -= tzinfo.StandardBias;
+    }
+    return offset;
+#else
+
+#if defined(sun) || defined(__sun) || defined(_AIX)
+    // 'tm_gmtoff' field is BSD extension and it's missing on SunOS/Solaris
+    struct helper
+    {
+        static long int calculate_gmt_offset(const std::tm &localtm = details::os::localtime(), const std::tm &gmtm = details::os::gmtime())
+        {
+            int local_year = localtm.tm_year + (1900 - 1);
+            int gmt_year = gmtm.tm_year + (1900 - 1);
+
+            long int days = (
+                // difference in day of year
+                localtm.tm_yday -
+                gmtm.tm_yday
+
+                // + intervening leap days
+                + ((local_year >> 2) - (gmt_year >> 2)) - (local_year / 100 - gmt_year / 100) +
+                ((local_year / 100 >> 2) - (gmt_year / 100 >> 2))
+
+                // + difference in years * 365 */
+                + (long int)(local_year - gmt_year) * 365);
+
+            long int hours = (24 * days) + (localtm.tm_hour - gmtm.tm_hour);
+            long int mins = (60 * hours) + (localtm.tm_min - gmtm.tm_min);
+            long int secs = (60 * mins) + (localtm.tm_sec - gmtm.tm_sec);
+
+            return secs;
+        }
+    };
+
+    auto offset_seconds = helper::calculate_gmt_offset(tm);
+#else
+    auto offset_seconds = tm.tm_gmtoff;
+#endif
+
+    return static_cast<int>(offset_seconds / 60);
+#endif
+}
+
+// Return current thread id as size_t
+// It exists because the std::this_thread::get_id() is much slower(especially under VS 2013)
+inline size_t _thread_id()
+{
+#ifdef _WIN32
+    return static_cast<size_t>(::GetCurrentThreadId());
+#elif __linux__
+#if defined(__ANDROID__) && defined(__ANDROID_API__) && (__ANDROID_API__ < 21)
+#define SYS_gettid __NR_gettid
+#endif
+    return static_cast<size_t>(syscall(SYS_gettid));
+#elif __FreeBSD__
+    long tid;
+    thr_self(&tid);
+    return static_cast<size_t>(tid);
+#elif __APPLE__
+    uint64_t tid;
+    pthread_threadid_np(nullptr, &tid);
+    return static_cast<size_t>(tid);
+#else // Default to standard C++11 (other Unix)
+    return static_cast<size_t>(std::hash<std::thread::id>()(std::this_thread::get_id()));
+#endif
+}
+
+// Return current thread id as size_t (from thread local storage)
+inline size_t thread_id()
+{
+#if defined(SPDLOG_DISABLE_TID_CACHING) || (defined(_MSC_VER) && (_MSC_VER < 1900)) || defined(__cplusplus_winrt) ||                       \
+    (defined(__clang__) && !__has_feature(cxx_thread_local))
+    return _thread_id();
+#else // cache thread id in tls
+    static thread_local const size_t tid = _thread_id();
+    return tid;
+#endif
+}
+
+// This is avoid msvc issue in sleep_for that happens if the clock changes.
+// See https://github.com/gabime/spdlog/issues/609
+inline void sleep_for_millis(int milliseconds)
+{
+#if defined(_WIN32)
+    ::Sleep(milliseconds);
+#else
+    std::this_thread::sleep_for(std::chrono::milliseconds(milliseconds));
+#endif
+}
+
+// wchar support for windows file names (SPDLOG_WCHAR_FILENAMES must be defined)
+#if defined(_WIN32) && defined(SPDLOG_WCHAR_FILENAMES)
+#define SPDLOG_FILENAME_T(s) L##s
+inline std::string filename_to_str(const filename_t &filename)
+{
+    std::wstring_convert<std::codecvt_utf8<wchar_t>, wchar_t> c;
+    return c.to_bytes(filename);
+}
+#else
+#define SPDLOG_FILENAME_T(s) s
+inline std::string filename_to_str(const filename_t &filename)
+{
+    return filename;
+}
+#endif
+
+inline int pid()
+{
+
+#ifdef _WIN32
+    return static_cast<int>(::GetCurrentProcessId());
+#else
+    return static_cast<int>(::getpid());
+#endif
+}
+
+// Determine if the terminal supports colors
+// Source: https://github.com/agauniyal/rang/
+inline bool is_color_terminal()
+{
+#ifdef _WIN32
+    return true;
+#else
+    static constexpr const char *Terms[] = {
+        "ansi", "color", "console", "cygwin", "gnome", "konsole", "kterm", "linux", "msys", "putty", "rxvt", "screen", "vt100", "xterm"};
+
+    const char *env_p = std::getenv("TERM");
+    if (env_p == nullptr)
+    {
+        return false;
+    }
+
+    static const bool result =
+        std::any_of(std::begin(Terms), std::end(Terms), [&](const char *term) { return std::strstr(env_p, term) != nullptr; });
+    return result;
+#endif
+}
+
+// Detrmine if the terminal attached
+// Source: https://github.com/agauniyal/rang/
+inline bool in_terminal(FILE *file)
+{
+
+#ifdef _WIN32
+    return _isatty(_fileno(file)) != 0;
+#else
+    return isatty(fileno(file)) != 0;
+#endif
+}
+} // namespace os
+} // namespace details
+} // namespace spdlog
diff --git a/lib/spdlog/details/pattern_formatter_impl.h b/lib/spdlog/details/pattern_formatter_impl.h
new file mode 100644
index 0000000..e3d7087
--- /dev/null
+++ b/lib/spdlog/details/pattern_formatter_impl.h
@@ -0,0 +1,707 @@
+//
+// Copyright(c) 2015 Gabi Melman.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+//
+
+#pragma once
+
+#include "../details/log_msg.h"
+#include "../details/os.h"
+#include "../fmt/fmt.h"
+#include "../formatter.h"
+
+#include <array>
+#include <chrono>
+#include <ctime>
+#include <memory>
+#include <mutex>
+#include <string>
+#include <thread>
+#include <utility>
+#include <vector>
+
+namespace spdlog {
+namespace details {
+class flag_formatter
+{
+public:
+    virtual ~flag_formatter() = default;
+    virtual void format(details::log_msg &msg, const std::tm &tm_time) = 0;
+};
+
+///////////////////////////////////////////////////////////////////////
+// name & level pattern appenders
+///////////////////////////////////////////////////////////////////////
+class name_formatter : public flag_formatter
+{
+    void format(details::log_msg &msg, const std::tm &) override
+    {
+        msg.formatted << *msg.logger_name;
+    }
+};
+
+// log level appender
+class level_formatter : public flag_formatter
+{
+    void format(details::log_msg &msg, const std::tm &) override
+    {
+        msg.formatted << level::to_str(msg.level);
+    }
+};
+
+// short log level appender
+class short_level_formatter : public flag_formatter
+{
+    void format(details::log_msg &msg, const std::tm &) override
+    {
+        msg.formatted << level::to_short_str(msg.level);
+    }
+};
+
+///////////////////////////////////////////////////////////////////////
+// Date time pattern appenders
+///////////////////////////////////////////////////////////////////////
+
+static const char *ampm(const tm &t)
+{
+    return t.tm_hour >= 12 ? "PM" : "AM";
+}
+
+static int to12h(const tm &t)
+{
+    return t.tm_hour > 12 ? t.tm_hour - 12 : t.tm_hour;
+}
+
+// Abbreviated weekday name
+static const std::string days[]{"Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat"};
+class a_formatter : public flag_formatter
+{
+    void format(details::log_msg &msg, const std::tm &tm_time) override
+    {
+        msg.formatted << days[tm_time.tm_wday];
+    }
+};
+
+// Full weekday name
+static const std::string full_days[]{"Sunday", "Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday"};
+class A_formatter : public flag_formatter
+{
+    void format(details::log_msg &msg, const std::tm &tm_time) override
+    {
+        msg.formatted << full_days[tm_time.tm_wday];
+    }
+};
+
+// Abbreviated month
+static const std::string months[]{"Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul", "Aug", "Sept", "Oct", "Nov", "Dec"};
+class b_formatter : public flag_formatter
+{
+    void format(details::log_msg &msg, const std::tm &tm_time) override
+    {
+        msg.formatted << months[tm_time.tm_mon];
+    }
+};
+
+// Full month name
+static const std::string full_months[]{
+    "January", "February", "March", "April", "May", "June", "July", "August", "September", "October", "November", "December"};
+class B_formatter : public flag_formatter
+{
+    void format(details::log_msg &msg, const std::tm &tm_time) override
+    {
+        msg.formatted << full_months[tm_time.tm_mon];
+    }
+};
+
+// write 2 ints separated by sep with padding of 2
+static fmt::MemoryWriter &pad_n_join(fmt::MemoryWriter &w, int v1, int v2, char sep)
+{
+    w << fmt::pad(v1, 2, '0') << sep << fmt::pad(v2, 2, '0');
+    return w;
+}
+
+// write 3 ints separated by sep with padding of 2
+static fmt::MemoryWriter &pad_n_join(fmt::MemoryWriter &w, int v1, int v2, int v3, char sep)
+{
+    w << fmt::pad(v1, 2, '0') << sep << fmt::pad(v2, 2, '0') << sep << fmt::pad(v3, 2, '0');
+    return w;
+}
+
+// Date and time representation (Thu Aug 23 15:35:46 2014)
+class c_formatter SPDLOG_FINAL : public flag_formatter
+{
+    void format(details::log_msg &msg, const std::tm &tm_time) override
+    {
+        msg.formatted << days[tm_time.tm_wday] << ' ' << months[tm_time.tm_mon] << ' ' << tm_time.tm_mday << ' ';
+        pad_n_join(msg.formatted, tm_time.tm_hour, tm_time.tm_min, tm_time.tm_sec, ':') << ' ' << tm_time.tm_year + 1900;
+    }
+};
+
+// year - 2 digit
+class C_formatter SPDLOG_FINAL : public flag_formatter
+{
+    void format(details::log_msg &msg, const std::tm &tm_time) override
+    {
+        msg.formatted << fmt::pad(tm_time.tm_year % 100, 2, '0');
+    }
+};
+
+// Short MM/DD/YY date, equivalent to %m/%d/%y 08/23/01
+class D_formatter SPDLOG_FINAL : public flag_formatter
+{
+    void format(details::log_msg &msg, const std::tm &tm_time) override
+    {
+        pad_n_join(msg.formatted, tm_time.tm_mon + 1, tm_time.tm_mday, tm_time.tm_year % 100, '/');
+    }
+};
+
+// year - 4 digit
+class Y_formatter SPDLOG_FINAL : public flag_formatter
+{
+    void format(details::log_msg &msg, const std::tm &tm_time) override
+    {
+        msg.formatted << tm_time.tm_year + 1900;
+    }
+};
+
+// month 1-12
+class m_formatter SPDLOG_FINAL : public flag_formatter
+{
+    void format(details::log_msg &msg, const std::tm &tm_time) override
+    {
+        msg.formatted << fmt::pad(tm_time.tm_mon + 1, 2, '0');
+    }
+};
+
+// day of month 1-31
+class d_formatter SPDLOG_FINAL : public flag_formatter
+{
+    void format(details::log_msg &msg, const std::tm &tm_time) override
+    {
+        msg.formatted << fmt::pad(tm_time.tm_mday, 2, '0');
+    }
+};
+
+// hours in 24 format 0-23
+class H_formatter SPDLOG_FINAL : public flag_formatter
+{
+    void format(details::log_msg &msg, const std::tm &tm_time) override
+    {
+        msg.formatted << fmt::pad(tm_time.tm_hour, 2, '0');
+    }
+};
+
+// hours in 12 format 1-12
+class I_formatter SPDLOG_FINAL : public flag_formatter
+{
+    void format(details::log_msg &msg, const std::tm &tm_time) override
+    {
+        msg.formatted << fmt::pad(to12h(tm_time), 2, '0');
+    }
+};
+
+// minutes 0-59
+class M_formatter SPDLOG_FINAL : public flag_formatter
+{
+    void format(details::log_msg &msg, const std::tm &tm_time) override
+    {
+        msg.formatted << fmt::pad(tm_time.tm_min, 2, '0');
+    }
+};
+
+// seconds 0-59
+class S_formatter SPDLOG_FINAL : public flag_formatter
+{
+    void format(details::log_msg &msg, const std::tm &tm_time) override
+    {
+        msg.formatted << fmt::pad(tm_time.tm_sec, 2, '0');
+    }
+};
+
+// milliseconds
+class e_formatter SPDLOG_FINAL : public flag_formatter
+{
+    void format(details::log_msg &msg, const std::tm &) override
+    {
+        auto duration = msg.time.time_since_epoch();
+        auto millis = std::chrono::duration_cast<std::chrono::milliseconds>(duration).count() % 1000;
+        msg.formatted << fmt::pad(static_cast<int>(millis), 3, '0');
+    }
+};
+
+// microseconds
+class f_formatter SPDLOG_FINAL : public flag_formatter
+{
+    void format(details::log_msg &msg, const std::tm &) override
+    {
+        auto duration = msg.time.time_since_epoch();
+        auto micros = std::chrono::duration_cast<std::chrono::microseconds>(duration).count() % 1000000;
+        msg.formatted << fmt::pad(static_cast<int>(micros), 6, '0');
+    }
+};
+
+// nanoseconds
+class F_formatter SPDLOG_FINAL : public flag_formatter
+{
+    void format(details::log_msg &msg, const std::tm &) override
+    {
+        auto duration = msg.time.time_since_epoch();
+        auto ns = std::chrono::duration_cast<std::chrono::nanoseconds>(duration).count() % 1000000000;
+        msg.formatted << fmt::pad(static_cast<int>(ns), 9, '0');
+    }
+};
+
+class E_formatter SPDLOG_FINAL : public flag_formatter
+{
+    void format(details::log_msg &msg, const std::tm &) override
+    {
+        auto duration = msg.time.time_since_epoch();
+        auto seconds = std::chrono::duration_cast<std::chrono::seconds>(duration).count();
+        msg.formatted << seconds;
+    }
+};
+
+// AM/PM
+class p_formatter SPDLOG_FINAL : public flag_formatter
+{
+    void format(details::log_msg &msg, const std::tm &tm_time) override
+    {
+        msg.formatted << ampm(tm_time);
+    }
+};
+
+// 12 hour clock 02:55:02 pm
+class r_formatter SPDLOG_FINAL : public flag_formatter
+{
+    void format(details::log_msg &msg, const std::tm &tm_time) override
+    {
+        pad_n_join(msg.formatted, to12h(tm_time), tm_time.tm_min, tm_time.tm_sec, ':') << ' ' << ampm(tm_time);
+    }
+};
+
+// 24-hour HH:MM time, equivalent to %H:%M
+class R_formatter SPDLOG_FINAL : public flag_formatter
+{
+    void format(details::log_msg &msg, const std::tm &tm_time) override
+    {
+        pad_n_join(msg.formatted, tm_time.tm_hour, tm_time.tm_min, ':');
+    }
+};
+
+// ISO 8601 time format (HH:MM:SS), equivalent to %H:%M:%S
+class T_formatter SPDLOG_FINAL : public flag_formatter
+{
+    void format(details::log_msg &msg, const std::tm &tm_time) override
+    {
+        pad_n_join(msg.formatted, tm_time.tm_hour, tm_time.tm_min, tm_time.tm_sec, ':');
+    }
+};
+
+// ISO 8601 offset from UTC in timezone (+-HH:MM)
+class z_formatter SPDLOG_FINAL : public flag_formatter
+{
+public:
+    const std::chrono::seconds cache_refresh = std::chrono::seconds(5);
+
+    z_formatter() = default;
+    z_formatter(const z_formatter &) = delete;
+    z_formatter &operator=(const z_formatter &) = delete;
+
+    void format(details::log_msg &msg, const std::tm &tm_time) override
+    {
+#ifdef _WIN32
+        int total_minutes = get_cached_offset(msg, tm_time);
+#else
+        // No need to chache under gcc,
+        // it is very fast (already stored in tm.tm_gmtoff)
+        int total_minutes = os::utc_minutes_offset(tm_time);
+#endif
+        bool is_negative = total_minutes < 0;
+        char sign;
+        if (is_negative)
+        {
+            total_minutes = -total_minutes;
+            sign = '-';
+        }
+        else
+        {
+            sign = '+';
+        }
+
+        int h = total_minutes / 60;
+        int m = total_minutes % 60;
+        msg.formatted << sign;
+        pad_n_join(msg.formatted, h, m, ':');
+    }
+
+private:
+    log_clock::time_point _last_update{std::chrono::seconds(0)};
+    int _offset_minutes{0};
+    std::mutex _mutex;
+
+    int get_cached_offset(const log_msg &msg, const std::tm &tm_time)
+    {
+        std::lock_guard<std::mutex> l(_mutex);
+        if (msg.time - _last_update >= cache_refresh)
+        {
+            _offset_minutes = os::utc_minutes_offset(tm_time);
+            _last_update = msg.time;
+        }
+        return _offset_minutes;
+    }
+};
+
+// Thread id
+class t_formatter SPDLOG_FINAL : public flag_formatter
+{
+    void format(details::log_msg &msg, const std::tm &) override
+    {
+        msg.formatted << msg.thread_id;
+    }
+};
+
+// Current pid
+class pid_formatter SPDLOG_FINAL : public flag_formatter
+{
+    void format(details::log_msg &msg, const std::tm &) override
+    {
+        msg.formatted << details::os::pid();
+    }
+};
+
+// message counter formatter
+class i_formatter SPDLOG_FINAL : public flag_formatter
+{
+    void format(details::log_msg &msg, const std::tm &) override
+    {
+        msg.formatted << fmt::pad(msg.msg_id, 6, '0');
+    }
+};
+
+class v_formatter SPDLOG_FINAL : public flag_formatter
+{
+    void format(details::log_msg &msg, const std::tm &) override
+    {
+        msg.formatted << fmt::StringRef(msg.raw.data(), msg.raw.size());
+    }
+};
+
+class ch_formatter SPDLOG_FINAL : public flag_formatter
+{
+public:
+    explicit ch_formatter(char ch)
+        : _ch(ch)
+    {
+    }
+    void format(details::log_msg &msg, const std::tm &) override
+    {
+        msg.formatted << _ch;
+    }
+
+private:
+    char _ch;
+};
+
+// aggregate user chars to display as is
+class aggregate_formatter SPDLOG_FINAL : public flag_formatter
+{
+public:
+    aggregate_formatter() = default;
+
+    void add_ch(char ch)
+    {
+        _str += ch;
+    }
+    void format(details::log_msg &msg, const std::tm &) override
+    {
+        msg.formatted << _str;
+    }
+
+private:
+    std::string _str;
+};
+
+// mark the color range. expect it to be in the form of "%^colored text%$"
+class color_start_formatter SPDLOG_FINAL : public flag_formatter
+{
+    void format(details::log_msg &msg, const std::tm &) override
+    {
+        msg.color_range_start = msg.formatted.size();
+    }
+};
+class color_stop_formatter SPDLOG_FINAL : public flag_formatter
+{
+    void format(details::log_msg &msg, const std::tm &) override
+    {
+        msg.color_range_end = msg.formatted.size();
+    }
+};
+
+// Full info formatter
+// pattern: [%Y-%m-%d %H:%M:%S.%e] [%n] [%l] %v
+class full_formatter SPDLOG_FINAL : public flag_formatter
+{
+    void format(details::log_msg &msg, const std::tm &tm_time) override
+    {
+#ifndef SPDLOG_NO_DATETIME
+        auto duration = msg.time.time_since_epoch();
+        auto millis = std::chrono::duration_cast<std::chrono::milliseconds>(duration).count() % 1000;
+
+        /* Slower version(while still very fast - about 3.2 million lines/sec under 10 threads),
+        msg.formatted.write("[{:d}-{:02d}-{:02d} {:02d}:{:02d}:{:02d}.{:03d}] [{}] [{}] {} ",
+        tm_time.tm_year + 1900,
+        tm_time.tm_mon + 1,
+        tm_time.tm_mday,
+        tm_time.tm_hour,
+        tm_time.tm_min,
+        tm_time.tm_sec,
+        static_cast<int>(millis),
+        msg.logger_name,
+        level::to_str(msg.level),
+        msg.raw.str());*/
+
+        // Faster (albeit uglier) way to format the line (5.6 million lines/sec under 10 threads)
+        msg.formatted << '[' << static_cast<unsigned int>(tm_time.tm_year + 1900) << '-'
+                      << fmt::pad(static_cast<unsigned int>(tm_time.tm_mon + 1), 2, '0') << '-'
+                      << fmt::pad(static_cast<unsigned int>(tm_time.tm_mday), 2, '0') << ' '
+                      << fmt::pad(static_cast<unsigned int>(tm_time.tm_hour), 2, '0') << ':'
+                      << fmt::pad(static_cast<unsigned int>(tm_time.tm_min), 2, '0') << ':'
+                      << fmt::pad(static_cast<unsigned int>(tm_time.tm_sec), 2, '0') << '.'
+                      << fmt::pad(static_cast<unsigned int>(millis), 3, '0') << "] ";
+
+        // no datetime needed
+#else
+        (void)tm_time;
+#endif
+
+#ifndef SPDLOG_NO_NAME
+        msg.formatted << '[' << *msg.logger_name << "] ";
+#endif
+
+        msg.formatted << '[';
+        // wrap the level name with color
+        msg.color_range_start = msg.formatted.size();
+        msg.formatted << level::to_str(msg.level);
+        msg.color_range_end = msg.formatted.size();
+        msg.formatted << "] " << fmt::StringRef(msg.raw.data(), msg.raw.size());
+    }
+};
+
+} // namespace details
+} // namespace spdlog
+///////////////////////////////////////////////////////////////////////////////
+// pattern_formatter inline impl
+///////////////////////////////////////////////////////////////////////////////
+inline spdlog::pattern_formatter::pattern_formatter(const std::string &pattern, pattern_time_type pattern_time, std::string eol)
+    : _eol(std::move(eol))
+    , _pattern_time(pattern_time)
+{
+    compile_pattern(pattern);
+}
+
+inline void spdlog::pattern_formatter::compile_pattern(const std::string &pattern)
+{
+    auto end = pattern.end();
+    std::unique_ptr<details::aggregate_formatter> user_chars;
+    for (auto it = pattern.begin(); it != end; ++it)
+    {
+        if (*it == '%')
+        {
+            if (user_chars) // append user chars found so far
+            {
+                _formatters.push_back(std::move(user_chars));
+            }
+            // if(
+            if (++it != end)
+            {
+                handle_flag(*it);
+            }
+            else
+            {
+                break;
+            }
+        }
+        else // chars not following the % sign should be displayed as is
+        {
+            if (!user_chars)
+            {
+                user_chars = std::unique_ptr<details::aggregate_formatter>(new details::aggregate_formatter());
+            }
+            user_chars->add_ch(*it);
+        }
+    }
+    if (user_chars) // append raw chars found so far
+    {
+        _formatters.push_back(std::move(user_chars));
+    }
+}
+inline void spdlog::pattern_formatter::handle_flag(char flag)
+{
+    switch (flag)
+    {
+    // logger name
+    case 'n':
+        _formatters.emplace_back(new details::name_formatter());
+        break;
+
+    case 'l':
+        _formatters.emplace_back(new details::level_formatter());
+        break;
+
+    case 'L':
+        _formatters.emplace_back(new details::short_level_formatter());
+        break;
+
+    case ('t'):
+        _formatters.emplace_back(new details::t_formatter());
+        break;
+
+    case ('v'):
+        _formatters.emplace_back(new details::v_formatter());
+        break;
+
+    case ('a'):
+        _formatters.emplace_back(new details::a_formatter());
+        break;
+
+    case ('A'):
+        _formatters.emplace_back(new details::A_formatter());
+        break;
+
+    case ('b'):
+    case ('h'):
+        _formatters.emplace_back(new details::b_formatter());
+        break;
+
+    case ('B'):
+        _formatters.emplace_back(new details::B_formatter());
+        break;
+    case ('c'):
+        _formatters.emplace_back(new details::c_formatter());
+        break;
+
+    case ('C'):
+        _formatters.emplace_back(new details::C_formatter());
+        break;
+
+    case ('Y'):
+        _formatters.emplace_back(new details::Y_formatter());
+        break;
+
+    case ('D'):
+    case ('x'):
+
+        _formatters.emplace_back(new details::D_formatter());
+        break;
+
+    case ('m'):
+        _formatters.emplace_back(new details::m_formatter());
+        break;
+
+    case ('d'):
+        _formatters.emplace_back(new details::d_formatter());
+        break;
+
+    case ('H'):
+        _formatters.emplace_back(new details::H_formatter());
+        break;
+
+    case ('I'):
+        _formatters.emplace_back(new details::I_formatter());
+        break;
+
+    case ('M'):
+        _formatters.emplace_back(new details::M_formatter());
+        break;
+
+    case ('S'):
+        _formatters.emplace_back(new details::S_formatter());
+        break;
+
+    case ('e'):
+        _formatters.emplace_back(new details::e_formatter());
+        break;
+
+    case ('f'):
+        _formatters.emplace_back(new details::f_formatter());
+        break;
+    case ('F'):
+        _formatters.emplace_back(new details::F_formatter());
+        break;
+
+    case ('E'):
+        _formatters.emplace_back(new details::E_formatter());
+        break;
+
+    case ('p'):
+        _formatters.emplace_back(new details::p_formatter());
+        break;
+
+    case ('r'):
+        _formatters.emplace_back(new details::r_formatter());
+        break;
+
+    case ('R'):
+        _formatters.emplace_back(new details::R_formatter());
+        break;
+
+    case ('T'):
+    case ('X'):
+        _formatters.emplace_back(new details::T_formatter());
+        break;
+
+    case ('z'):
+        _formatters.emplace_back(new details::z_formatter());
+        break;
+
+    case ('+'):
+        _formatters.emplace_back(new details::full_formatter());
+        break;
+
+    case ('P'):
+        _formatters.emplace_back(new details::pid_formatter());
+        break;
+
+    case ('i'):
+        _formatters.emplace_back(new details::i_formatter());
+        break;
+
+    case ('^'):
+        _formatters.emplace_back(new details::color_start_formatter());
+        break;
+
+    case ('$'):
+        _formatters.emplace_back(new details::color_stop_formatter());
+        break;
+
+    default: // Unknown flag appears as is
+        _formatters.emplace_back(new details::ch_formatter('%'));
+        _formatters.emplace_back(new details::ch_formatter(flag));
+        break;
+    }
+}
+
+inline std::tm spdlog::pattern_formatter::get_time(details::log_msg &msg)
+{
+    if (_pattern_time == pattern_time_type::local)
+    {
+        return details::os::localtime(log_clock::to_time_t(msg.time));
+    }
+    return details::os::gmtime(log_clock::to_time_t(msg.time));
+}
+
+inline void spdlog::pattern_formatter::format(details::log_msg &msg)
+{
+
+#ifndef SPDLOG_NO_DATETIME
+    auto tm_time = get_time(msg);
+#else
+    std::tm tm_time;
+#endif
+    for (auto &f : _formatters)
+    {
+        f->format(msg, tm_time);
+    }
+    // write eol
+    msg.formatted << _eol;
+}
diff --git a/lib/spdlog/details/registry.h b/lib/spdlog/details/registry.h
new file mode 100644
index 0000000..614220d
--- /dev/null
+++ b/lib/spdlog/details/registry.h
@@ -0,0 +1,263 @@
+//
+// Copyright(c) 2015 Gabi Melman.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+//
+
+#pragma once
+
+// Loggers registy of unique name->logger pointer
+// An attempt to create a logger with an already existing name will be ignored
+// If user requests a non existing logger, nullptr will be returned
+// This class is thread safe
+
+#include "../async_logger.h"
+#include "../common.h"
+#include "../details/null_mutex.h"
+#include "../logger.h"
+
+#include <chrono>
+#include <functional>
+#include <memory>
+#include <mutex>
+#include <string>
+#include <unordered_map>
+
+namespace spdlog {
+namespace details {
+template<class Mutex>
+class registry_t
+{
+public:
+    registry_t<Mutex>(const registry_t<Mutex> &) = delete;
+    registry_t<Mutex> &operator=(const registry_t<Mutex> &) = delete;
+
+    void register_logger(std::shared_ptr<logger> logger)
+    {
+        std::lock_guard<Mutex> lock(_mutex);
+        auto logger_name = logger->name();
+        throw_if_exists(logger_name);
+        _loggers[logger_name] = logger;
+    }
+
+    std::shared_ptr<logger> get(const std::string &logger_name)
+    {
+        std::lock_guard<Mutex> lock(_mutex);
+        auto found = _loggers.find(logger_name);
+        return found == _loggers.end() ? nullptr : found->second;
+    }
+
+    template<class It>
+    std::shared_ptr<logger> create(const std::string &logger_name, const It &sinks_begin, const It &sinks_end)
+    {
+        std::lock_guard<Mutex> lock(_mutex);
+        throw_if_exists(logger_name);
+        std::shared_ptr<logger> new_logger;
+        if (_async_mode)
+        {
+            new_logger = std::make_shared<async_logger>(logger_name, sinks_begin, sinks_end, _async_q_size, _overflow_policy,
+                _worker_warmup_cb, _flush_interval_ms, _worker_teardown_cb);
+        }
+        else
+        {
+            new_logger = std::make_shared<logger>(logger_name, sinks_begin, sinks_end);
+        }
+
+        if (_formatter)
+        {
+            new_logger->set_formatter(_formatter);
+        }
+
+        if (_err_handler)
+        {
+            new_logger->set_error_handler(_err_handler);
+        }
+
+        new_logger->set_level(_level);
+        new_logger->flush_on(_flush_level);
+
+        // Add to registry
+        _loggers[logger_name] = new_logger;
+        return new_logger;
+    }
+
+    template<class It>
+    std::shared_ptr<async_logger> create_async(const std::string &logger_name, size_t queue_size,
+        const async_overflow_policy overflow_policy, const std::function<void()> &worker_warmup_cb,
+        const std::chrono::milliseconds &flush_interval_ms, const std::function<void()> &worker_teardown_cb, const It &sinks_begin,
+        const It &sinks_end)
+    {
+        std::lock_guard<Mutex> lock(_mutex);
+        throw_if_exists(logger_name);
+        auto new_logger = std::make_shared<async_logger>(
+            logger_name, sinks_begin, sinks_end, queue_size, overflow_policy, worker_warmup_cb, flush_interval_ms, worker_teardown_cb);
+
+        if (_formatter)
+        {
+            new_logger->set_formatter(_formatter);
+        }
+
+        if (_err_handler)
+        {
+            new_logger->set_error_handler(_err_handler);
+        }
+
+        new_logger->set_level(_level);
+        new_logger->flush_on(_flush_level);
+
+        // Add to registry
+        _loggers[logger_name] = new_logger;
+        return new_logger;
+    }
+
+    void apply_all(std::function<void(std::shared_ptr<logger>)> fun)
+    {
+        std::lock_guard<Mutex> lock(_mutex);
+        for (auto &l : _loggers)
+        {
+            fun(l.second);
+        }
+    }
+
+    void drop(const std::string &logger_name)
+    {
+        std::lock_guard<Mutex> lock(_mutex);
+        _loggers.erase(logger_name);
+    }
+
+    void drop_all()
+    {
+        std::lock_guard<Mutex> lock(_mutex);
+        _loggers.clear();
+    }
+
+    std::shared_ptr<logger> create(const std::string &logger_name, sinks_init_list sinks)
+    {
+        return create(logger_name, sinks.begin(), sinks.end());
+    }
+
+    std::shared_ptr<logger> create(const std::string &logger_name, sink_ptr sink)
+    {
+        return create(logger_name, {sink});
+    }
+
+    std::shared_ptr<async_logger> create_async(const std::string &logger_name, size_t queue_size,
+        const async_overflow_policy overflow_policy, const std::function<void()> &worker_warmup_cb,
+        const std::chrono::milliseconds &flush_interval_ms, const std::function<void()> &worker_teardown_cb, sinks_init_list sinks)
+    {
+        return create_async(
+            logger_name, queue_size, overflow_policy, worker_warmup_cb, flush_interval_ms, worker_teardown_cb, sinks.begin(), sinks.end());
+    }
+
+    std::shared_ptr<async_logger> create_async(const std::string &logger_name, size_t queue_size,
+        const async_overflow_policy overflow_policy, const std::function<void()> &worker_warmup_cb,
+        const std::chrono::milliseconds &flush_interval_ms, const std::function<void()> &worker_teardown_cb, sink_ptr sink)
+    {
+        return create_async(logger_name, queue_size, overflow_policy, worker_warmup_cb, flush_interval_ms, worker_teardown_cb, {sink});
+    }
+
+    void formatter(formatter_ptr f)
+    {
+        std::lock_guard<Mutex> lock(_mutex);
+        _formatter = f;
+        for (auto &l : _loggers)
+        {
+            l.second->set_formatter(_formatter);
+        }
+    }
+
+    void set_pattern(const std::string &pattern)
+    {
+        std::lock_guard<Mutex> lock(_mutex);
+        _formatter = std::make_shared<pattern_formatter>(pattern);
+        for (auto &l : _loggers)
+        {
+            l.second->set_formatter(_formatter);
+        }
+    }
+
+    void set_level(level::level_enum log_level)
+    {
+        std::lock_guard<Mutex> lock(_mutex);
+        for (auto &l : _loggers)
+        {
+            l.second->set_level(log_level);
+        }
+        _level = log_level;
+    }
+
+    void flush_on(level::level_enum log_level)
+    {
+        std::lock_guard<Mutex> lock(_mutex);
+        for (auto &l : _loggers)
+        {
+            l.second->flush_on(log_level);
+        }
+        _flush_level = log_level;
+    }
+
+    void set_error_handler(log_err_handler handler)
+    {
+        for (auto &l : _loggers)
+        {
+            l.second->set_error_handler(handler);
+        }
+        _err_handler = handler;
+    }
+
+    void set_async_mode(size_t q_size, const async_overflow_policy overflow_policy, const std::function<void()> &worker_warmup_cb,
+        const std::chrono::milliseconds &flush_interval_ms, const std::function<void()> &worker_teardown_cb)
+    {
+        std::lock_guard<Mutex> lock(_mutex);
+        _async_mode = true;
+        _async_q_size = q_size;
+        _overflow_policy = overflow_policy;
+        _worker_warmup_cb = worker_warmup_cb;
+        _flush_interval_ms = flush_interval_ms;
+        _worker_teardown_cb = worker_teardown_cb;
+    }
+
+    void set_sync_mode()
+    {
+        std::lock_guard<Mutex> lock(_mutex);
+        _async_mode = false;
+    }
+
+    static registry_t<Mutex> &instance()
+    {
+        static registry_t<Mutex> s_instance;
+        return s_instance;
+    }
+
+private:
+    registry_t<Mutex>() = default;
+
+    void throw_if_exists(const std::string &logger_name)
+    {
+        if (_loggers.find(logger_name) != _loggers.end())
+        {
+            throw spdlog_ex("logger with name '" + logger_name + "' already exists");
+        }
+    }
+
+    Mutex _mutex;
+    std::unordered_map<std::string, std::shared_ptr<logger>> _loggers;
+    formatter_ptr _formatter;
+    level::level_enum _level = level::info;
+    level::level_enum _flush_level = level::off;
+    log_err_handler _err_handler;
+    bool _async_mode = false;
+    size_t _async_q_size = 0;
+    async_overflow_policy _overflow_policy = async_overflow_policy::block_retry;
+    std::function<void()> _worker_warmup_cb;
+    std::chrono::milliseconds _flush_interval_ms{std::chrono::milliseconds::zero()};
+    std::function<void()> _worker_teardown_cb;
+};
+
+#ifdef SPDLOG_NO_REGISTRY_MUTEX
+using registry = registry_t<spdlog::details::null_mutex>;
+#else
+using registry = registry_t<std::mutex>;
+#endif
+
+} // namespace details
+} // namespace spdlog
diff --git a/lib/spdlog/details/spdlog_impl.h b/lib/spdlog/details/spdlog_impl.h
new file mode 100644
index 0000000..4c36383
--- /dev/null
+++ b/lib/spdlog/details/spdlog_impl.h
@@ -0,0 +1,278 @@
+//
+// Copyright(c) 2015 Gabi Melman.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+//
+
+#pragma once
+
+//
+// Global registry functions
+//
+#include "../details/registry.h"
+#include "../sinks/file_sinks.h"
+#include "../sinks/stdout_sinks.h"
+#include "../spdlog.h"
+#ifdef SPDLOG_ENABLE_SYSLOG
+#include "../sinks/syslog_sink.h"
+#endif
+
+#if defined _WIN32 && !defined(__cplusplus_winrt)
+#include "../sinks/wincolor_sink.h"
+#else
+#include "../sinks/ansicolor_sink.h"
+#endif
+
+#ifdef __ANDROID__
+#include "../sinks/android_sink.h"
+#endif
+
+#include <chrono>
+#include <functional>
+#include <memory>
+#include <string>
+
+inline void spdlog::register_logger(std::shared_ptr<logger> logger)
+{
+    return details::registry::instance().register_logger(std::move(logger));
+}
+
+inline std::shared_ptr<spdlog::logger> spdlog::get(const std::string &name)
+{
+    return details::registry::instance().get(name);
+}
+
+inline void spdlog::drop(const std::string &name)
+{
+    details::registry::instance().drop(name);
+}
+
+// Create multi/single threaded simple file logger
+inline std::shared_ptr<spdlog::logger> spdlog::basic_logger_mt(const std::string &logger_name, const filename_t &filename, bool truncate)
+{
+    return create<spdlog::sinks::simple_file_sink_mt>(logger_name, filename, truncate);
+}
+
+inline std::shared_ptr<spdlog::logger> spdlog::basic_logger_st(const std::string &logger_name, const filename_t &filename, bool truncate)
+{
+    return create<spdlog::sinks::simple_file_sink_st>(logger_name, filename, truncate);
+}
+
+// Create multi/single threaded rotating file logger
+inline std::shared_ptr<spdlog::logger> spdlog::rotating_logger_mt(
+    const std::string &logger_name, const filename_t &filename, size_t max_file_size, size_t max_files)
+{
+    return create<spdlog::sinks::rotating_file_sink_mt>(logger_name, filename, max_file_size, max_files);
+}
+
+inline std::shared_ptr<spdlog::logger> spdlog::rotating_logger_st(
+    const std::string &logger_name, const filename_t &filename, size_t max_file_size, size_t max_files)
+{
+    return create<spdlog::sinks::rotating_file_sink_st>(logger_name, filename, max_file_size, max_files);
+}
+
+// Create file logger which creates new file at midnight):
+inline std::shared_ptr<spdlog::logger> spdlog::daily_logger_mt(
+    const std::string &logger_name, const filename_t &filename, int hour, int minute)
+{
+    return create<spdlog::sinks::daily_file_sink_mt>(logger_name, filename, hour, minute);
+}
+
+inline std::shared_ptr<spdlog::logger> spdlog::daily_logger_st(
+    const std::string &logger_name, const filename_t &filename, int hour, int minute)
+{
+    return create<spdlog::sinks::daily_file_sink_st>(logger_name, filename, hour, minute);
+}
+
+//
+// stdout/stderr loggers
+//
+inline std::shared_ptr<spdlog::logger> spdlog::stdout_logger_mt(const std::string &logger_name)
+{
+    return spdlog::details::registry::instance().create(logger_name, spdlog::sinks::stdout_sink_mt::instance());
+}
+
+inline std::shared_ptr<spdlog::logger> spdlog::stdout_logger_st(const std::string &logger_name)
+{
+    return spdlog::details::registry::instance().create(logger_name, spdlog::sinks::stdout_sink_st::instance());
+}
+
+inline std::shared_ptr<spdlog::logger> spdlog::stderr_logger_mt(const std::string &logger_name)
+{
+    return spdlog::details::registry::instance().create(logger_name, spdlog::sinks::stderr_sink_mt::instance());
+}
+
+inline std::shared_ptr<spdlog::logger> spdlog::stderr_logger_st(const std::string &logger_name)
+{
+    return spdlog::details::registry::instance().create(logger_name, spdlog::sinks::stderr_sink_st::instance());
+}
+
+//
+// stdout/stderr color loggers
+//
+#if defined _WIN32 && !defined(__cplusplus_winrt)
+
+inline std::shared_ptr<spdlog::logger> spdlog::stdout_color_mt(const std::string &logger_name)
+{
+    auto sink = std::make_shared<spdlog::sinks::wincolor_stdout_sink_mt>();
+    return spdlog::details::registry::instance().create(logger_name, sink);
+}
+
+inline std::shared_ptr<spdlog::logger> spdlog::stdout_color_st(const std::string &logger_name)
+{
+    auto sink = std::make_shared<spdlog::sinks::wincolor_stdout_sink_st>();
+    return spdlog::details::registry::instance().create(logger_name, sink);
+}
+
+inline std::shared_ptr<spdlog::logger> spdlog::stderr_color_mt(const std::string &logger_name)
+{
+    auto sink = std::make_shared<spdlog::sinks::wincolor_stderr_sink_mt>();
+    return spdlog::details::registry::instance().create(logger_name, sink);
+}
+
+inline std::shared_ptr<spdlog::logger> spdlog::stderr_color_st(const std::string &logger_name)
+{
+    auto sink = std::make_shared<spdlog::sinks::wincolor_stderr_sink_st>();
+    return spdlog::details::registry::instance().create(logger_name, sink);
+}
+
+#else // ansi terminal colors
+
+inline std::shared_ptr<spdlog::logger> spdlog::stdout_color_mt(const std::string &logger_name)
+{
+    auto sink = std::make_shared<spdlog::sinks::ansicolor_stdout_sink_mt>();
+    return spdlog::details::registry::instance().create(logger_name, sink);
+}
+
+inline std::shared_ptr<spdlog::logger> spdlog::stdout_color_st(const std::string &logger_name)
+{
+    auto sink = std::make_shared<spdlog::sinks::ansicolor_stdout_sink_st>();
+    return spdlog::details::registry::instance().create(logger_name, sink);
+}
+
+inline std::shared_ptr<spdlog::logger> spdlog::stderr_color_mt(const std::string &logger_name)
+{
+    auto sink = std::make_shared<spdlog::sinks::ansicolor_stderr_sink_mt>();
+    return spdlog::details::registry::instance().create(logger_name, sink);
+}
+
+inline std::shared_ptr<spdlog::logger> spdlog::stderr_color_st(const std::string &logger_name)
+{
+    auto sink = std::make_shared<spdlog::sinks::ansicolor_stderr_sink_st>();
+    return spdlog::details::registry::instance().create(logger_name, sink);
+}
+#endif
+
+#ifdef SPDLOG_ENABLE_SYSLOG
+// Create syslog logger
+inline std::shared_ptr<spdlog::logger> spdlog::syslog_logger(
+    const std::string &logger_name, const std::string &syslog_ident, int syslog_option, int syslog_facility)
+{
+    return create<spdlog::sinks::syslog_sink>(logger_name, syslog_ident, syslog_option, syslog_facility);
+}
+#endif
+
+#ifdef __ANDROID__
+inline std::shared_ptr<spdlog::logger> spdlog::android_logger(const std::string &logger_name, const std::string &tag)
+{
+    return create<spdlog::sinks::android_sink>(logger_name, tag);
+}
+#endif
+
+// Create and register a logger a single sink
+inline std::shared_ptr<spdlog::logger> spdlog::create(const std::string &logger_name, const spdlog::sink_ptr &sink)
+{
+    return details::registry::instance().create(logger_name, sink);
+}
+
+// Create logger with multiple sinks
+inline std::shared_ptr<spdlog::logger> spdlog::create(const std::string &logger_name, spdlog::sinks_init_list sinks)
+{
+    return details::registry::instance().create(logger_name, sinks);
+}
+
+template<typename Sink, typename... Args>
+inline std::shared_ptr<spdlog::logger> spdlog::create(const std::string &logger_name, Args... args)
+{
+    sink_ptr sink = std::make_shared<Sink>(args...);
+    return details::registry::instance().create(logger_name, {sink});
+}
+
+template<class It>
+inline std::shared_ptr<spdlog::logger> spdlog::create(const std::string &logger_name, const It &sinks_begin, const It &sinks_end)
+{
+    return details::registry::instance().create(logger_name, sinks_begin, sinks_end);
+}
+
+// Create and register an async logger with a single sink
+inline std::shared_ptr<spdlog::logger> spdlog::create_async(const std::string &logger_name, const sink_ptr &sink, size_t queue_size,
+    const async_overflow_policy overflow_policy, const std::function<void()> &worker_warmup_cb,
+    const std::chrono::milliseconds &flush_interval_ms, const std::function<void()> &worker_teardown_cb)
+{
+    return details::registry::instance().create_async(
+        logger_name, queue_size, overflow_policy, worker_warmup_cb, flush_interval_ms, worker_teardown_cb, sink);
+}
+
+// Create and register an async logger with multiple sinks
+inline std::shared_ptr<spdlog::logger> spdlog::create_async(const std::string &logger_name, sinks_init_list sinks, size_t queue_size,
+    const async_overflow_policy overflow_policy, const std::function<void()> &worker_warmup_cb,
+    const std::chrono::milliseconds &flush_interval_ms, const std::function<void()> &worker_teardown_cb)
+{
+    return details::registry::instance().create_async(
+        logger_name, queue_size, overflow_policy, worker_warmup_cb, flush_interval_ms, worker_teardown_cb, sinks);
+}
+
+template<class It>
+inline std::shared_ptr<spdlog::logger> spdlog::create_async(const std::string &logger_name, const It &sinks_begin, const It &sinks_end,
+    size_t queue_size, const async_overflow_policy overflow_policy, const std::function<void()> &worker_warmup_cb,
+    const std::chrono::milliseconds &flush_interval_ms, const std::function<void()> &worker_teardown_cb)
+{
+    return details::registry::instance().create_async(
+        logger_name, queue_size, overflow_policy, worker_warmup_cb, flush_interval_ms, worker_teardown_cb, sinks_begin, sinks_end);
+}
+
+inline void spdlog::set_formatter(spdlog::formatter_ptr f)
+{
+    details::registry::instance().formatter(std::move(f));
+}
+
+inline void spdlog::set_pattern(const std::string &format_string)
+{
+    return details::registry::instance().set_pattern(format_string);
+}
+
+inline void spdlog::set_level(level::level_enum log_level)
+{
+    return details::registry::instance().set_level(log_level);
+}
+
+inline void spdlog::flush_on(level::level_enum log_level)
+{
+    return details::registry::instance().flush_on(log_level);
+}
+
+inline void spdlog::set_error_handler(log_err_handler handler)
+{
+    return details::registry::instance().set_error_handler(std::move(handler));
+}
+
+inline void spdlog::set_async_mode(size_t queue_size, const async_overflow_policy overflow_policy,
+    const std::function<void()> &worker_warmup_cb, const std::chrono::milliseconds &flush_interval_ms,
+    const std::function<void()> &worker_teardown_cb)
+{
+    details::registry::instance().set_async_mode(queue_size, overflow_policy, worker_warmup_cb, flush_interval_ms, worker_teardown_cb);
+}
+
+inline void spdlog::set_sync_mode()
+{
+    details::registry::instance().set_sync_mode();
+}
+
+inline void spdlog::apply_all(std::function<void(std::shared_ptr<logger>)> fun)
+{
+    details::registry::instance().apply_all(std::move(fun));
+}
+
+inline void spdlog::drop_all()
+{
+    details::registry::instance().drop_all();
+}
diff --git a/lib/spdlog/fmt/bundled/LICENSE.rst b/lib/spdlog/fmt/bundled/LICENSE.rst
new file mode 100644
index 0000000..eb6be65
--- /dev/null
+++ b/lib/spdlog/fmt/bundled/LICENSE.rst
@@ -0,0 +1,23 @@
+Copyright (c) 2012 - 2016, Victor Zverovich
+
+All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are met:
+
+1. Redistributions of source code must retain the above copyright notice, this
+   list of conditions and the following disclaimer.
+2. Redistributions in binary form must reproduce the above copyright notice,
+   this list of conditions and the following disclaimer in the documentation
+   and/or other materials provided with the distribution.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
+ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
+ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+(INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
diff --git a/lib/spdlog/fmt/bundled/format.cc b/lib/spdlog/fmt/bundled/format.cc
new file mode 100644
index 0000000..2d236bc
--- /dev/null
+++ b/lib/spdlog/fmt/bundled/format.cc
@@ -0,0 +1,495 @@
+/*
+ Formatting library for C++
+
+ Copyright (c) 2012 - 2016, Victor Zverovich
+ All rights reserved.
+
+ Redistribution and use in source and binary forms, with or without
+ modification, are permitted provided that the following conditions are met:
+
+ 1. Redistributions of source code must retain the above copyright notice, this
+    list of conditions and the following disclaimer.
+ 2. Redistributions in binary form must reproduce the above copyright notice,
+    this list of conditions and the following disclaimer in the documentation
+    and/or other materials provided with the distribution.
+
+ THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
+ ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+ WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
+ ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include "format.h"
+
+#include <string.h>
+
+#include <cctype>
+#include <cerrno>
+#include <climits>
+#include <cmath>
+#include <cstdarg>
+#include <cstddef>  // for std::ptrdiff_t
+
+#if defined(_WIN32) && defined(__MINGW32__)
+# include <cstring>
+#endif
+
+#if FMT_USE_WINDOWS_H
+# if !defined(FMT_HEADER_ONLY) && !defined(WIN32_LEAN_AND_MEAN)
+#  define WIN32_LEAN_AND_MEAN
+# endif
+# if defined(NOMINMAX) || defined(FMT_WIN_MINMAX)
+#  include <windows.h>
+# else
+#  define NOMINMAX
+#  include <windows.h>
+#  undef NOMINMAX
+# endif
+#endif
+
+#if FMT_EXCEPTIONS
+# define FMT_TRY try
+# define FMT_CATCH(x) catch (x)
+#else
+# define FMT_TRY if (true)
+# define FMT_CATCH(x) if (false)
+#endif
+
+#ifdef _MSC_VER
+# pragma warning(push)
+# pragma warning(disable: 4127)  // conditional expression is constant
+# pragma warning(disable: 4702)  // unreachable code
+// Disable deprecation warning for strerror. The latter is not called but
+// MSVC fails to detect it.
+# pragma warning(disable: 4996)
+#endif
+
+// Dummy implementations of strerror_r and strerror_s called if corresponding
+// system functions are not available.
+FMT_MAYBE_UNUSED
+static inline fmt::internal::Null<> strerror_r(int, char *, ...) {
+  return fmt::internal::Null<>();
+}
+FMT_MAYBE_UNUSED
+static inline fmt::internal::Null<> strerror_s(char *, std::size_t, ...) {
+  return fmt::internal::Null<>();
+}
+
+namespace fmt {
+
+FMT_FUNC internal::RuntimeError::~RuntimeError() FMT_DTOR_NOEXCEPT {}
+FMT_FUNC FormatError::~FormatError() FMT_DTOR_NOEXCEPT {}
+FMT_FUNC SystemError::~SystemError() FMT_DTOR_NOEXCEPT {}
+
+namespace {
+
+#ifndef _MSC_VER
+# define FMT_SNPRINTF snprintf
+#else  // _MSC_VER
+inline int fmt_snprintf(char *buffer, size_t size, const char *format, ...) {
+  va_list args;
+  va_start(args, format);
+  int result = vsnprintf_s(buffer, size, _TRUNCATE, format, args);
+  va_end(args);
+  return result;
+}
+# define FMT_SNPRINTF fmt_snprintf
+#endif  // _MSC_VER
+
+#if defined(_WIN32) && defined(__MINGW32__) && !defined(__NO_ISOCEXT)
+# define FMT_SWPRINTF snwprintf
+#else
+# define FMT_SWPRINTF swprintf
+#endif // defined(_WIN32) && defined(__MINGW32__) && !defined(__NO_ISOCEXT)
+
+const char RESET_COLOR[] = "\x1b[0m";
+
+typedef void (*FormatFunc)(Writer &, int, StringRef);
+
+// Portable thread-safe version of strerror.
+// Sets buffer to point to a string describing the error code.
+// This can be either a pointer to a string stored in buffer,
+// or a pointer to some static immutable string.
+// Returns one of the following values:
+//   0      - success
+//   ERANGE - buffer is not large enough to store the error message
+//   other  - failure
+// Buffer should be at least of size 1.
+int safe_strerror(
+    int error_code, char *&buffer, std::size_t buffer_size) FMT_NOEXCEPT {
+  FMT_ASSERT(buffer != FMT_NULL && buffer_size != 0, "invalid buffer");
+
+  class StrError {
+   private:
+    int error_code_;
+    char *&buffer_;
+    std::size_t buffer_size_;
+
+    // A noop assignment operator to avoid bogus warnings.
+    void operator=(const StrError &) {}
+
+    // Handle the result of XSI-compliant version of strerror_r.
+    int handle(int result) {
+      // glibc versions before 2.13 return result in errno.
+      return result == -1 ? errno : result;
+    }
+
+    // Handle the result of GNU-specific version of strerror_r.
+    int handle(char *message) {
+      // If the buffer is full then the message is probably truncated.
+      if (message == buffer_ && strlen(buffer_) == buffer_size_ - 1)
+        return ERANGE;
+      buffer_ = message;
+      return 0;
+    }
+
+    // Handle the case when strerror_r is not available.
+    int handle(internal::Null<>) {
+      return fallback(strerror_s(buffer_, buffer_size_, error_code_));
+    }
+
+    // Fallback to strerror_s when strerror_r is not available.
+    int fallback(int result) {
+      // If the buffer is full then the message is probably truncated.
+      return result == 0 && strlen(buffer_) == buffer_size_ - 1 ?
+            ERANGE : result;
+    }
+
+#ifdef __c2__
+# pragma clang diagnostic push
+# pragma clang diagnostic ignored "-Wdeprecated-declarations"
+#endif
+
+    // Fallback to strerror if strerror_r and strerror_s are not available.
+    int fallback(internal::Null<>) {
+      errno = 0;
+      buffer_ = strerror(error_code_);
+      return errno;
+    }
+
+#ifdef __c2__
+# pragma clang diagnostic pop
+#endif
+
+   public:
+    StrError(int err_code, char *&buf, std::size_t buf_size)
+      : error_code_(err_code), buffer_(buf), buffer_size_(buf_size) {}
+
+    int run() {
+      return handle(strerror_r(error_code_, buffer_, buffer_size_));
+    }
+  };
+  return StrError(error_code, buffer, buffer_size).run();
+}
+
+void format_error_code(Writer &out, int error_code,
+                       StringRef message) FMT_NOEXCEPT {
+  // Report error code making sure that the output fits into
+  // INLINE_BUFFER_SIZE to avoid dynamic memory allocation and potential
+  // bad_alloc.
+  out.clear();
+  static const char SEP[] = ": ";
+  static const char ERROR_STR[] = "error ";
+  // Subtract 2 to account for terminating null characters in SEP and ERROR_STR.
+  std::size_t error_code_size = sizeof(SEP) + sizeof(ERROR_STR) - 2;
+  typedef internal::IntTraits<int>::MainType MainType;
+  MainType abs_value = static_cast<MainType>(error_code);
+  if (internal::is_negative(error_code)) {
+    abs_value = 0 - abs_value;
+    ++error_code_size;
+  }
+  error_code_size += internal::count_digits(abs_value);
+  if (message.size() <= internal::INLINE_BUFFER_SIZE - error_code_size)
+    out << message << SEP;
+  out << ERROR_STR << error_code;
+  assert(out.size() <= internal::INLINE_BUFFER_SIZE);
+}
+
+void report_error(FormatFunc func, int error_code,
+                  StringRef message) FMT_NOEXCEPT {
+  MemoryWriter full_message;
+  func(full_message, error_code, message);
+  // Use Writer::data instead of Writer::c_str to avoid potential memory
+  // allocation.
+  std::fwrite(full_message.data(), full_message.size(), 1, stderr);
+  std::fputc('\n', stderr);
+}
+}  // namespace
+
+FMT_FUNC void SystemError::init(
+    int err_code, CStringRef format_str, ArgList args) {
+  error_code_ = err_code;
+  MemoryWriter w;
+  format_system_error(w, err_code, format(format_str, args));
+  std::runtime_error &base = *this;
+  base = std::runtime_error(w.str());
+}
+
+template <typename T>
+int internal::CharTraits<char>::format_float(
+    char *buffer, std::size_t size, const char *format,
+    unsigned width, int precision, T value) {
+  if (width == 0) {
+    return precision < 0 ?
+        FMT_SNPRINTF(buffer, size, format, value) :
+        FMT_SNPRINTF(buffer, size, format, precision, value);
+  }
+  return precision < 0 ?
+      FMT_SNPRINTF(buffer, size, format, width, value) :
+      FMT_SNPRINTF(buffer, size, format, width, precision, value);
+}
+
+template <typename T>
+int internal::CharTraits<wchar_t>::format_float(
+    wchar_t *buffer, std::size_t size, const wchar_t *format,
+    unsigned width, int precision, T value) {
+  if (width == 0) {
+    return precision < 0 ?
+        FMT_SWPRINTF(buffer, size, format, value) :
+        FMT_SWPRINTF(buffer, size, format, precision, value);
+  }
+  return precision < 0 ?
+      FMT_SWPRINTF(buffer, size, format, width, value) :
+      FMT_SWPRINTF(buffer, size, format, width, precision, value);
+}
+
+template <typename T>
+const char internal::BasicData<T>::DIGITS[] =
+    "0001020304050607080910111213141516171819"
+    "2021222324252627282930313233343536373839"
+    "4041424344454647484950515253545556575859"
+    "6061626364656667686970717273747576777879"
+    "8081828384858687888990919293949596979899";
+
+#define FMT_POWERS_OF_10(factor) \
+  factor * 10, \
+  factor * 100, \
+  factor * 1000, \
+  factor * 10000, \
+  factor * 100000, \
+  factor * 1000000, \
+  factor * 10000000, \
+  factor * 100000000, \
+  factor * 1000000000
+
+template <typename T>
+const uint32_t internal::BasicData<T>::POWERS_OF_10_32[] = {
+  0, FMT_POWERS_OF_10(1)
+};
+
+template <typename T>
+const uint64_t internal::BasicData<T>::POWERS_OF_10_64[] = {
+  0,
+  FMT_POWERS_OF_10(1),
+  FMT_POWERS_OF_10(ULongLong(1000000000)),
+  // Multiply several constants instead of using a single long long constant
+  // to avoid warnings about C++98 not supporting long long.
+  ULongLong(1000000000) * ULongLong(1000000000) * 10
+};
+
+FMT_FUNC void internal::report_unknown_type(char code, const char *type) {
+  (void)type;
+  if (std::isprint(static_cast<unsigned char>(code))) {
+    FMT_THROW(FormatError(
+        format("unknown format code '{}' for {}", code, type)));
+  }
+  FMT_THROW(FormatError(
+      format("unknown format code '\\x{:02x}' for {}",
+        static_cast<unsigned>(code), type)));
+}
+
+#if FMT_USE_WINDOWS_H
+
+FMT_FUNC internal::UTF8ToUTF16::UTF8ToUTF16(StringRef s) {
+  static const char ERROR_MSG[] = "cannot convert string from UTF-8 to UTF-16";
+  if (s.size() > INT_MAX)
+    FMT_THROW(WindowsError(ERROR_INVALID_PARAMETER, ERROR_MSG));
+  int s_size = static_cast<int>(s.size());
+  int length = MultiByteToWideChar(
+      CP_UTF8, MB_ERR_INVALID_CHARS, s.data(), s_size, FMT_NULL, 0);
+  if (length == 0)
+    FMT_THROW(WindowsError(GetLastError(), ERROR_MSG));
+  buffer_.resize(length + 1);
+  length = MultiByteToWideChar(
+    CP_UTF8, MB_ERR_INVALID_CHARS, s.data(), s_size, &buffer_[0], length);
+  if (length == 0)
+    FMT_THROW(WindowsError(GetLastError(), ERROR_MSG));
+  buffer_[length] = 0;
+}
+
+FMT_FUNC internal::UTF16ToUTF8::UTF16ToUTF8(WStringRef s) {
+  if (int error_code = convert(s)) {
+    FMT_THROW(WindowsError(error_code,
+        "cannot convert string from UTF-16 to UTF-8"));
+  }
+}
+
+FMT_FUNC int internal::UTF16ToUTF8::convert(WStringRef s) {
+  if (s.size() > INT_MAX)
+    return ERROR_INVALID_PARAMETER;
+  int s_size = static_cast<int>(s.size());
+  int length = WideCharToMultiByte(
+    CP_UTF8, 0, s.data(), s_size, FMT_NULL, 0, FMT_NULL, FMT_NULL);
+  if (length == 0)
+    return GetLastError();
+  buffer_.resize(length + 1);
+  length = WideCharToMultiByte(
+    CP_UTF8, 0, s.data(), s_size, &buffer_[0], length, FMT_NULL, FMT_NULL);
+  if (length == 0)
+    return GetLastError();
+  buffer_[length] = 0;
+  return 0;
+}
+
+FMT_FUNC void WindowsError::init(
+    int err_code, CStringRef format_str, ArgList args) {
+  error_code_ = err_code;
+  MemoryWriter w;
+  internal::format_windows_error(w, err_code, format(format_str, args));
+  std::runtime_error &base = *this;
+  base = std::runtime_error(w.str());
+}
+
+FMT_FUNC void internal::format_windows_error(
+    Writer &out, int error_code, StringRef message) FMT_NOEXCEPT {
+  FMT_TRY {
+    MemoryBuffer<wchar_t, INLINE_BUFFER_SIZE> buffer;
+    buffer.resize(INLINE_BUFFER_SIZE);
+    for (;;) {
+      wchar_t *system_message = &buffer[0];
+      int result = FormatMessageW(
+        FORMAT_MESSAGE_FROM_SYSTEM | FORMAT_MESSAGE_IGNORE_INSERTS,
+        FMT_NULL, error_code, MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT),
+        system_message, static_cast<uint32_t>(buffer.size()), FMT_NULL);
+      if (result != 0) {
+        UTF16ToUTF8 utf8_message;
+        if (utf8_message.convert(system_message) == ERROR_SUCCESS) {
+          out << message << ": " << utf8_message;
+          return;
+        }
+        break;
+      }
+      if (GetLastError() != ERROR_INSUFFICIENT_BUFFER)
+        break;  // Can't get error message, report error code instead.
+      buffer.resize(buffer.size() * 2);
+    }
+  } FMT_CATCH(...) {}
+  fmt::format_error_code(out, error_code, message);  // 'fmt::' is for bcc32.
+}
+
+#endif  // FMT_USE_WINDOWS_H
+
+FMT_FUNC void format_system_error(
+    Writer &out, int error_code, StringRef message) FMT_NOEXCEPT {
+  FMT_TRY {
+    internal::MemoryBuffer<char, internal::INLINE_BUFFER_SIZE> buffer;
+    buffer.resize(internal::INLINE_BUFFER_SIZE);
+    for (;;) {
+      char *system_message = &buffer[0];
+      int result = safe_strerror(error_code, system_message, buffer.size());
+      if (result == 0) {
+        out << message << ": " << system_message;
+        return;
+      }
+      if (result != ERANGE)
+        break;  // Can't get error message, report error code instead.
+      buffer.resize(buffer.size() * 2);
+    }
+  } FMT_CATCH(...) {}
+  fmt::format_error_code(out, error_code, message);  // 'fmt::' is for bcc32.
+}
+
+template <typename Char>
+void internal::FixedBuffer<Char>::grow(std::size_t) {
+  FMT_THROW(std::runtime_error("buffer overflow"));
+}
+
+FMT_FUNC internal::Arg internal::FormatterBase::do_get_arg(
+    unsigned arg_index, const char *&error) {
+  internal::Arg arg = args_[arg_index];
+  switch (arg.type) {
+  case internal::Arg::NONE:
+    error = "argument index out of range";
+    break;
+  case internal::Arg::NAMED_ARG:
+    arg = *static_cast<const internal::Arg*>(arg.pointer);
+    break;
+  default:
+    /*nothing*/;
+  }
+  return arg;
+}
+
+FMT_FUNC void report_system_error(
+    int error_code, fmt::StringRef message) FMT_NOEXCEPT {
+  // 'fmt::' is for bcc32.
+  report_error(format_system_error, error_code, message);
+}
+
+#if FMT_USE_WINDOWS_H
+FMT_FUNC void report_windows_error(
+    int error_code, fmt::StringRef message) FMT_NOEXCEPT {
+  // 'fmt::' is for bcc32.
+  report_error(internal::format_windows_error, error_code, message);
+}
+#endif
+
+FMT_FUNC void print(std::FILE *f, CStringRef format_str, ArgList args) {
+  MemoryWriter w;
+  w.write(format_str, args);
+  std::fwrite(w.data(), 1, w.size(), f);
+}
+
+FMT_FUNC void print(CStringRef format_str, ArgList args) {
+  print(stdout, format_str, args);
+}
+
+FMT_FUNC void print_colored(Color c, CStringRef format, ArgList args) {
+  char escape[] = "\x1b[30m";
+  escape[3] = static_cast<char>('0' + c);
+  std::fputs(escape, stdout);
+  print(format, args);
+  std::fputs(RESET_COLOR, stdout);
+}
+
+#ifndef FMT_HEADER_ONLY
+
+template struct internal::BasicData<void>;
+
+// Explicit instantiations for char.
+
+template void internal::FixedBuffer<char>::grow(std::size_t);
+
+template FMT_API int internal::CharTraits<char>::format_float(
+    char *buffer, std::size_t size, const char *format,
+    unsigned width, int precision, double value);
+
+template FMT_API int internal::CharTraits<char>::format_float(
+    char *buffer, std::size_t size, const char *format,
+    unsigned width, int precision, long double value);
+
+// Explicit instantiations for wchar_t.
+
+template void internal::FixedBuffer<wchar_t>::grow(std::size_t);
+
+template FMT_API int internal::CharTraits<wchar_t>::format_float(
+    wchar_t *buffer, std::size_t size, const wchar_t *format,
+    unsigned width, int precision, double value);
+
+template FMT_API int internal::CharTraits<wchar_t>::format_float(
+    wchar_t *buffer, std::size_t size, const wchar_t *format,
+    unsigned width, int precision, long double value);
+
+#endif  // FMT_HEADER_ONLY
+
+}  // namespace fmt
+
+#ifdef _MSC_VER
+# pragma warning(pop)
+#endif
diff --git a/lib/spdlog/fmt/bundled/format.h b/lib/spdlog/fmt/bundled/format.h
new file mode 100644
index 0000000..b4295cd
--- /dev/null
+++ b/lib/spdlog/fmt/bundled/format.h
@@ -0,0 +1,4920 @@
+/*
+ Formatting library for C++
+
+ Copyright (c) 2012 - 2016, Victor Zverovich
+ All rights reserved.
+
+ Redistribution and use in source and binary forms, with or without
+ modification, are permitted provided that the following conditions are met:
+
+ 1. Redistributions of source code must retain the above copyright notice, this
+    list of conditions and the following disclaimer.
+ 2. Redistributions in binary form must reproduce the above copyright notice,
+    this list of conditions and the following disclaimer in the documentation
+    and/or other materials provided with the distribution.
+
+ THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
+ ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+ WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
+ ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifndef FMT_FORMAT_H_
+#define FMT_FORMAT_H_
+
+#define FMT_INCLUDE
+#include <cassert>
+#include <clocale>
+#include <cmath>
+#include <cstdio>
+#include <cstring>
+#include <limits>
+#include <memory>
+#include <stdexcept>
+#include <string>
+#include <utility> // for std::pair
+#include <vector>
+#undef FMT_INCLUDE
+
+// The fmt library version in the form major * 10000 + minor * 100 + patch.
+#define FMT_VERSION 40100
+
+#if defined(__has_include)
+#define FMT_HAS_INCLUDE(x) __has_include(x)
+#else
+#define FMT_HAS_INCLUDE(x) 0
+#endif
+
+#if (FMT_HAS_INCLUDE(<string_view>) && __cplusplus > 201402L) || (defined(_MSVC_LANG) && _MSVC_LANG > 201402L && _MSC_VER >= 1910)
+#include <string_view>
+#define FMT_HAS_STRING_VIEW 1
+#else
+#define FMT_HAS_STRING_VIEW 0
+#endif
+
+#if defined _SECURE_SCL && _SECURE_SCL
+#define FMT_SECURE_SCL _SECURE_SCL
+#else
+#define FMT_SECURE_SCL 0
+#endif
+
+#if FMT_SECURE_SCL
+#include <iterator>
+#endif
+
+#ifdef _MSC_VER
+#define FMT_MSC_VER _MSC_VER
+#else
+#define FMT_MSC_VER 0
+#endif
+
+#if FMT_MSC_VER && FMT_MSC_VER <= 1500
+typedef unsigned __int32 uint32_t;
+typedef unsigned __int64 uint64_t;
+typedef __int64 intmax_t;
+#else
+#include <stdint.h>
+#endif
+
+#if !defined(FMT_HEADER_ONLY) && defined(_WIN32)
+#ifdef FMT_EXPORT
+#define FMT_API __declspec(dllexport)
+#elif defined(FMT_SHARED)
+#define FMT_API __declspec(dllimport)
+#endif
+#endif
+#ifndef FMT_API
+#define FMT_API
+#endif
+
+#ifdef __GNUC__
+#define FMT_GCC_VERSION (__GNUC__ * 100 + __GNUC_MINOR__)
+#define FMT_GCC_EXTENSION __extension__
+#if FMT_GCC_VERSION >= 406
+#pragma GCC diagnostic push
+// Disable the warning about "long long" which is sometimes reported even
+// when using __extension__.
+#pragma GCC diagnostic ignored "-Wlong-long"
+// Disable the warning about declaration shadowing because it affects too
+// many valid cases.
+#pragma GCC diagnostic ignored "-Wshadow"
+// Disable the warning about implicit conversions that may change the sign of
+// an integer; silencing it otherwise would require many explicit casts.
+#pragma GCC diagnostic ignored "-Wsign-conversion"
+#endif
+#if __cplusplus >= 201103L || defined __GXX_EXPERIMENTAL_CXX0X__
+#define FMT_HAS_GXX_CXX11 1
+#endif
+#else
+#define FMT_GCC_VERSION 0
+#define FMT_GCC_EXTENSION
+#define FMT_HAS_GXX_CXX11 0
+#endif
+
+#if defined(__INTEL_COMPILER)
+#define FMT_ICC_VERSION __INTEL_COMPILER
+#elif defined(__ICL)
+#define FMT_ICC_VERSION __ICL
+#endif
+
+#if defined(__clang__) && !defined(FMT_ICC_VERSION)
+#define FMT_CLANG_VERSION (__clang_major__ * 100 + __clang_minor__)
+#pragma clang diagnostic push
+#pragma clang diagnostic ignored "-Wdocumentation-unknown-command"
+#pragma clang diagnostic ignored "-Wpadded"
+#endif
+
+#ifdef __GNUC_LIBSTD__
+#define FMT_GNUC_LIBSTD_VERSION (__GNUC_LIBSTD__ * 100 + __GNUC_LIBSTD_MINOR__)
+#endif
+
+#ifdef __has_feature
+#define FMT_HAS_FEATURE(x) __has_feature(x)
+#else
+#define FMT_HAS_FEATURE(x) 0
+#endif
+
+#ifdef __has_builtin
+#define FMT_HAS_BUILTIN(x) __has_builtin(x)
+#else
+#define FMT_HAS_BUILTIN(x) 0
+#endif
+
+#ifdef __has_cpp_attribute
+#define FMT_HAS_CPP_ATTRIBUTE(x) __has_cpp_attribute(x)
+#else
+#define FMT_HAS_CPP_ATTRIBUTE(x) 0
+#endif
+
+#if FMT_HAS_CPP_ATTRIBUTE(maybe_unused)
+#define FMT_HAS_CXX17_ATTRIBUTE_MAYBE_UNUSED
+// VC++ 1910 support /std: option and that will set _MSVC_LANG macro
+// Clang with Microsoft CodeGen doesn't define _MSVC_LANG macro
+#elif defined(_MSVC_LANG) && _MSVC_LANG > 201402 && _MSC_VER >= 1910
+#define FMT_HAS_CXX17_ATTRIBUTE_MAYBE_UNUSED
+#endif
+
+#ifdef FMT_HAS_CXX17_ATTRIBUTE_MAYBE_UNUSED
+#define FMT_MAYBE_UNUSED [[maybe_unused]]
+// g++/clang++ also support [[gnu::unused]]. However, we don't use it.
+#elif defined(__GNUC__)
+#define FMT_MAYBE_UNUSED __attribute__((unused))
+#else
+#define FMT_MAYBE_UNUSED
+#endif
+
+// Use the compiler's attribute noreturn
+#if defined(__MINGW32__) || defined(__MINGW64__)
+#define FMT_NORETURN __attribute__((noreturn))
+#elif FMT_HAS_CPP_ATTRIBUTE(noreturn) && __cplusplus >= 201103L
+#define FMT_NORETURN [[noreturn]]
+#else
+#define FMT_NORETURN
+#endif
+
+#ifndef FMT_USE_VARIADIC_TEMPLATES
+// Variadic templates are available in GCC since version 4.4
+// (http://gcc.gnu.org/projects/cxx0x.html) and in Visual C++
+// since version 2013.
+#define FMT_USE_VARIADIC_TEMPLATES                                                                                                         \
+    (FMT_HAS_FEATURE(cxx_variadic_templates) || (FMT_GCC_VERSION >= 404 && FMT_HAS_GXX_CXX11) || FMT_MSC_VER >= 1800)
+#endif
+
+#ifndef FMT_USE_RVALUE_REFERENCES
+// Don't use rvalue references when compiling with clang and an old libstdc++
+// as the latter doesn't provide std::move.
+#if defined(FMT_GNUC_LIBSTD_VERSION) && FMT_GNUC_LIBSTD_VERSION <= 402
+#define FMT_USE_RVALUE_REFERENCES 0
+#else
+#define FMT_USE_RVALUE_REFERENCES                                                                                                          \
+    (FMT_HAS_FEATURE(cxx_rvalue_references) || (FMT_GCC_VERSION >= 403 && FMT_HAS_GXX_CXX11) || FMT_MSC_VER >= 1600)
+#endif
+#endif
+
+#if __cplusplus >= 201103L || FMT_MSC_VER >= 1700
+#define FMT_USE_ALLOCATOR_TRAITS 1
+#else
+#define FMT_USE_ALLOCATOR_TRAITS 0
+#endif
+
+// Check if exceptions are disabled.
+#if defined(__GNUC__) && !defined(__EXCEPTIONS)
+#define FMT_EXCEPTIONS 0
+#endif
+#if FMT_MSC_VER && !_HAS_EXCEPTIONS
+#define FMT_EXCEPTIONS 0
+#endif
+#ifndef FMT_EXCEPTIONS
+#define FMT_EXCEPTIONS 1
+#endif
+
+#ifndef FMT_THROW
+#if FMT_EXCEPTIONS
+#define FMT_THROW(x) throw x
+#else
+#define FMT_THROW(x) assert(false)
+#endif
+#endif
+
+// Define FMT_USE_NOEXCEPT to make fmt use noexcept (C++11 feature).
+#ifndef FMT_USE_NOEXCEPT
+#define FMT_USE_NOEXCEPT 0
+#endif
+
+#if FMT_USE_NOEXCEPT || FMT_HAS_FEATURE(cxx_noexcept) || (FMT_GCC_VERSION >= 408 && FMT_HAS_GXX_CXX11) || FMT_MSC_VER >= 1900
+#define FMT_DETECTED_NOEXCEPT noexcept
+#else
+#define FMT_DETECTED_NOEXCEPT throw()
+#endif
+
+#ifndef FMT_NOEXCEPT
+#if FMT_EXCEPTIONS
+#define FMT_NOEXCEPT FMT_DETECTED_NOEXCEPT
+#else
+#define FMT_NOEXCEPT
+#endif
+#endif
+
+// This is needed because GCC still uses throw() in its headers when exceptions
+// are disabled.
+#if FMT_GCC_VERSION
+#define FMT_DTOR_NOEXCEPT FMT_DETECTED_NOEXCEPT
+#else
+#define FMT_DTOR_NOEXCEPT FMT_NOEXCEPT
+#endif
+
+#ifndef FMT_OVERRIDE
+#if (defined(FMT_USE_OVERRIDE) && FMT_USE_OVERRIDE) || FMT_HAS_FEATURE(cxx_override) || (FMT_GCC_VERSION >= 408 && FMT_HAS_GXX_CXX11) ||   \
+    FMT_MSC_VER >= 1900
+#define FMT_OVERRIDE override
+#else
+#define FMT_OVERRIDE
+#endif
+#endif
+
+#ifndef FMT_NULL
+#if FMT_HAS_FEATURE(cxx_nullptr) || (FMT_GCC_VERSION >= 408 && FMT_HAS_GXX_CXX11) || FMT_MSC_VER >= 1600
+#define FMT_NULL nullptr
+#else
+#define FMT_NULL NULL
+#endif
+#endif
+
+// A macro to disallow the copy constructor and operator= functions
+// This should be used in the private: declarations for a class
+#ifndef FMT_USE_DELETED_FUNCTIONS
+#define FMT_USE_DELETED_FUNCTIONS 0
+#endif
+
+#if FMT_USE_DELETED_FUNCTIONS || FMT_HAS_FEATURE(cxx_deleted_functions) || (FMT_GCC_VERSION >= 404 && FMT_HAS_GXX_CXX11) ||                \
+    FMT_MSC_VER >= 1800
+#define FMT_DELETED_OR_UNDEFINED = delete
+#define FMT_DISALLOW_COPY_AND_ASSIGN(TypeName)                                                                                             \
+    TypeName(const TypeName &) = delete;                                                                                                   \
+    TypeName &operator=(const TypeName &) = delete
+#else
+#define FMT_DELETED_OR_UNDEFINED
+#define FMT_DISALLOW_COPY_AND_ASSIGN(TypeName)                                                                                             \
+    TypeName(const TypeName &);                                                                                                            \
+    TypeName &operator=(const TypeName &)
+#endif
+
+#ifndef FMT_USE_DEFAULTED_FUNCTIONS
+#define FMT_USE_DEFAULTED_FUNCTIONS 0
+#endif
+
+#ifndef FMT_DEFAULTED_COPY_CTOR
+#if FMT_USE_DEFAULTED_FUNCTIONS || FMT_HAS_FEATURE(cxx_defaulted_functions) || (FMT_GCC_VERSION >= 404 && FMT_HAS_GXX_CXX11) ||            \
+    FMT_MSC_VER >= 1800
+#define FMT_DEFAULTED_COPY_CTOR(TypeName) TypeName(const TypeName &) = default;
+#else
+#define FMT_DEFAULTED_COPY_CTOR(TypeName)
+#endif
+#endif
+
+#ifndef FMT_USE_USER_DEFINED_LITERALS
+// All compilers which support UDLs also support variadic templates. This
+// makes the fmt::literals implementation easier. However, an explicit check
+// for variadic templates is added here just in case.
+// For Intel's compiler both it and the system gcc/msc must support UDLs.
+#if FMT_USE_VARIADIC_TEMPLATES && FMT_USE_RVALUE_REFERENCES &&                                                                             \
+    (FMT_HAS_FEATURE(cxx_user_literals) || (FMT_GCC_VERSION >= 407 && FMT_HAS_GXX_CXX11) || FMT_MSC_VER >= 1900) &&                        \
+    (!defined(FMT_ICC_VERSION) || FMT_ICC_VERSION >= 1500)
+#define FMT_USE_USER_DEFINED_LITERALS 1
+#else
+#define FMT_USE_USER_DEFINED_LITERALS 0
+#endif
+#endif
+
+#ifndef FMT_USE_EXTERN_TEMPLATES
+#define FMT_USE_EXTERN_TEMPLATES (FMT_CLANG_VERSION >= 209 || (FMT_GCC_VERSION >= 303 && FMT_HAS_GXX_CXX11))
+#endif
+
+#ifdef FMT_HEADER_ONLY
+// If header only do not use extern templates.
+#undef FMT_USE_EXTERN_TEMPLATES
+#define FMT_USE_EXTERN_TEMPLATES 0
+#endif
+
+#ifndef FMT_ASSERT
+#define FMT_ASSERT(condition, message) assert((condition) && message)
+#endif
+
+// __builtin_clz is broken in clang with Microsoft CodeGen:
+// https://github.com/fmtlib/fmt/issues/519
+#ifndef _MSC_VER
+#if FMT_GCC_VERSION >= 400 || FMT_HAS_BUILTIN(__builtin_clz)
+#define FMT_BUILTIN_CLZ(n) __builtin_clz(n)
+#endif
+
+#if FMT_GCC_VERSION >= 400 || FMT_HAS_BUILTIN(__builtin_clzll)
+#define FMT_BUILTIN_CLZLL(n) __builtin_clzll(n)
+#endif
+#endif
+
+// Some compilers masquerade as both MSVC and GCC-likes or
+// otherwise support __builtin_clz and __builtin_clzll, so
+// only define FMT_BUILTIN_CLZ using the MSVC intrinsics
+// if the clz and clzll builtins are not available.
+#if FMT_MSC_VER && !defined(FMT_BUILTIN_CLZLL) && !defined(_MANAGED)
+#include <intrin.h> // _BitScanReverse, _BitScanReverse64
+
+namespace fmt {
+namespace internal {
+// avoid Clang with Microsoft CodeGen's -Wunknown-pragmas warning
+#ifndef __clang__
+#pragma intrinsic(_BitScanReverse)
+#endif
+inline uint32_t clz(uint32_t x)
+{
+    unsigned long r = 0;
+    _BitScanReverse(&r, x);
+
+    assert(x != 0);
+    // Static analysis complains about using uninitialized data
+    // "r", but the only way that can happen is if "x" is 0,
+    // which the callers guarantee to not happen.
+#pragma warning(suppress : 6102)
+    return 31 - r;
+}
+#define FMT_BUILTIN_CLZ(n) fmt::internal::clz(n)
+
+// avoid Clang with Microsoft CodeGen's -Wunknown-pragmas warning
+#if defined(_WIN64) && !defined(__clang__)
+#pragma intrinsic(_BitScanReverse64)
+#endif
+
+inline uint32_t clzll(uint64_t x)
+{
+    unsigned long r = 0;
+#ifdef _WIN64
+    _BitScanReverse64(&r, x);
+#else
+    // Scan the high 32 bits.
+    if (_BitScanReverse(&r, static_cast<uint32_t>(x >> 32)))
+        return 63 - (r + 32);
+
+    // Scan the low 32 bits.
+    _BitScanReverse(&r, static_cast<uint32_t>(x));
+#endif
+
+    assert(x != 0);
+    // Static analysis complains about using uninitialized data
+    // "r", but the only way that can happen is if "x" is 0,
+    // which the callers guarantee to not happen.
+#pragma warning(suppress : 6102)
+    return 63 - r;
+}
+#define FMT_BUILTIN_CLZLL(n) fmt::internal::clzll(n)
+} // namespace internal
+} // namespace fmt
+#endif
+
+namespace fmt {
+namespace internal {
+struct DummyInt
+{
+    int data[2];
+    operator int() const
+    {
+        return 0;
+    }
+};
+typedef std::numeric_limits<fmt::internal::DummyInt> FPUtil;
+
+// Dummy implementations of system functions such as signbit and ecvt called
+// if the latter are not available.
+inline DummyInt signbit(...)
+{
+    return DummyInt();
+}
+inline DummyInt _ecvt_s(...)
+{
+    return DummyInt();
+}
+inline DummyInt isinf(...)
+{
+    return DummyInt();
+}
+inline DummyInt _finite(...)
+{
+    return DummyInt();
+}
+inline DummyInt isnan(...)
+{
+    return DummyInt();
+}
+inline DummyInt _isnan(...)
+{
+    return DummyInt();
+}
+
+// A helper function to suppress bogus "conditional expression is constant"
+// warnings.
+template<typename T>
+inline T const_check(T value)
+{
+    return value;
+}
+} // namespace internal
+} // namespace fmt
+
+namespace std {
+// Standard permits specialization of std::numeric_limits. This specialization
+// is used to resolve ambiguity between isinf and std::isinf in glibc:
+// https://gcc.gnu.org/bugzilla/show_bug.cgi?id=48891
+// and the same for isnan and signbit.
+template<>
+class numeric_limits<fmt::internal::DummyInt> : public std::numeric_limits<int>
+{
+public:
+    // Portable version of isinf.
+    template<typename T>
+    static bool isinfinity(T x)
+    {
+        using namespace fmt::internal;
+        // The resolution "priority" is:
+        // isinf macro > std::isinf > ::isinf > fmt::internal::isinf
+        if (const_check(sizeof(isinf(x)) == sizeof(bool) || sizeof(isinf(x)) == sizeof(int)))
+        {
+            return isinf(x) != 0;
+        }
+        return !_finite(static_cast<double>(x));
+    }
+
+    // Portable version of isnan.
+    template<typename T>
+    static bool isnotanumber(T x)
+    {
+        using namespace fmt::internal;
+        if (const_check(sizeof(isnan(x)) == sizeof(bool) || sizeof(isnan(x)) == sizeof(int)))
+        {
+            return isnan(x) != 0;
+        }
+        return _isnan(static_cast<double>(x)) != 0;
+    }
+
+    // Portable version of signbit.
+    static bool isnegative(double x)
+    {
+        using namespace fmt::internal;
+        if (const_check(sizeof(signbit(x)) == sizeof(bool) || sizeof(signbit(x)) == sizeof(int)))
+        {
+            return signbit(x) != 0;
+        }
+        if (x < 0)
+            return true;
+        if (!isnotanumber(x))
+            return false;
+        int dec = 0, sign = 0;
+        char buffer[2]; // The buffer size must be >= 2 or _ecvt_s will fail.
+        _ecvt_s(buffer, sizeof(buffer), x, 0, &dec, &sign);
+        return sign != 0;
+    }
+};
+} // namespace std
+
+namespace fmt {
+
+// Fix the warning about long long on older versions of GCC
+// that don't support the diagnostic pragma.
+FMT_GCC_EXTENSION typedef long long LongLong;
+FMT_GCC_EXTENSION typedef unsigned long long ULongLong;
+
+#if FMT_USE_RVALUE_REFERENCES
+using std::move;
+#endif
+
+template<typename Char>
+class BasicWriter;
+
+typedef BasicWriter<char> Writer;
+typedef BasicWriter<wchar_t> WWriter;
+
+template<typename Char>
+class ArgFormatter;
+
+struct FormatSpec;
+
+template<typename Impl, typename Char, typename Spec = fmt::FormatSpec>
+class BasicPrintfArgFormatter;
+
+template<typename CharType, typename ArgFormatter = fmt::ArgFormatter<CharType>>
+class BasicFormatter;
+
+/**
+  \rst
+  A string reference. It can be constructed from a C string or
+  ``std::basic_string``.
+
+  You can use one of the following typedefs for common character types:
+
+  +------------+-------------------------+
+  | Type       | Definition              |
+  +============+=========================+
+  | StringRef  | BasicStringRef<char>    |
+  +------------+-------------------------+
+  | WStringRef | BasicStringRef<wchar_t> |
+  +------------+-------------------------+
+
+  This class is most useful as a parameter type to allow passing
+  different types of strings to a function, for example::
+
+    template <typename... Args>
+    std::string format(StringRef format_str, const Args & ... args);
+
+    format("{}", 42);
+    format(std::string("{}"), 42);
+  \endrst
+ */
+template<typename Char>
+class BasicStringRef
+{
+private:
+    const Char *data_;
+    std::size_t size_;
+
+public:
+    /** Constructs a string reference object from a C string and a size. */
+    BasicStringRef(const Char *s, std::size_t size)
+        : data_(s)
+        , size_(size)
+    {
+    }
+
+    /**
+      \rst
+      Constructs a string reference object from a C string computing
+      the size with ``std::char_traits<Char>::length``.
+      \endrst
+     */
+    BasicStringRef(const Char *s)
+        : data_(s)
+        , size_(std::char_traits<Char>::length(s))
+    {
+    }
+
+    /**
+      \rst
+      Constructs a string reference from a ``std::basic_string`` object.
+      \endrst
+     */
+    template<typename Allocator>
+    BasicStringRef(const std::basic_string<Char, std::char_traits<Char>, Allocator> &s)
+        : data_(s.c_str())
+        , size_(s.size())
+    {
+    }
+
+#if FMT_HAS_STRING_VIEW
+    /**
+      \rst
+      Constructs a string reference from a ``std::basic_string_view`` object.
+      \endrst
+     */
+    BasicStringRef(const std::basic_string_view<Char, std::char_traits<Char>> &s)
+        : data_(s.data())
+        , size_(s.size())
+    {
+    }
+
+    /**
+     \rst
+     Converts a string reference to an ``std::string_view`` object.
+     \endrst
+    */
+    explicit operator std::basic_string_view<Char>() const FMT_NOEXCEPT
+    {
+        return std::basic_string_view<Char>(data_, size_);
+    }
+#endif
+
+    /**
+      \rst
+      Converts a string reference to an ``std::string`` object.
+      \endrst
+     */
+    std::basic_string<Char> to_string() const
+    {
+        return std::basic_string<Char>(data_, size_);
+    }
+
+    /** Returns a pointer to the string data. */
+    const Char *data() const
+    {
+        return data_;
+    }
+
+    /** Returns the string size. */
+    std::size_t size() const
+    {
+        return size_;
+    }
+
+    // Lexicographically compare this string reference to other.
+    int compare(BasicStringRef other) const
+    {
+        std::size_t size = size_ < other.size_ ? size_ : other.size_;
+        int result = std::char_traits<Char>::compare(data_, other.data_, size);
+        if (result == 0)
+            result = size_ == other.size_ ? 0 : (size_ < other.size_ ? -1 : 1);
+        return result;
+    }
+
+    friend bool operator==(BasicStringRef lhs, BasicStringRef rhs)
+    {
+        return lhs.compare(rhs) == 0;
+    }
+    friend bool operator!=(BasicStringRef lhs, BasicStringRef rhs)
+    {
+        return lhs.compare(rhs) != 0;
+    }
+    friend bool operator<(BasicStringRef lhs, BasicStringRef rhs)
+    {
+        return lhs.compare(rhs) < 0;
+    }
+    friend bool operator<=(BasicStringRef lhs, BasicStringRef rhs)
+    {
+        return lhs.compare(rhs) <= 0;
+    }
+    friend bool operator>(BasicStringRef lhs, BasicStringRef rhs)
+    {
+        return lhs.compare(rhs) > 0;
+    }
+    friend bool operator>=(BasicStringRef lhs, BasicStringRef rhs)
+    {
+        return lhs.compare(rhs) >= 0;
+    }
+};
+
+typedef BasicStringRef<char> StringRef;
+typedef BasicStringRef<wchar_t> WStringRef;
+
+/**
+  \rst
+  A reference to a null terminated string. It can be constructed from a C
+  string or ``std::basic_string``.
+
+  You can use one of the following typedefs for common character types:
+
+  +-------------+--------------------------+
+  | Type        | Definition               |
+  +=============+==========================+
+  | CStringRef  | BasicCStringRef<char>    |
+  +-------------+--------------------------+
+  | WCStringRef | BasicCStringRef<wchar_t> |
+  +-------------+--------------------------+
+
+  This class is most useful as a parameter type to allow passing
+  different types of strings to a function, for example::
+
+    template <typename... Args>
+    std::string format(CStringRef format_str, const Args & ... args);
+
+    format("{}", 42);
+    format(std::string("{}"), 42);
+  \endrst
+ */
+template<typename Char>
+class BasicCStringRef
+{
+private:
+    const Char *data_;
+
+public:
+    /** Constructs a string reference object from a C string. */
+    BasicCStringRef(const Char *s)
+        : data_(s)
+    {
+    }
+
+    /**
+      \rst
+      Constructs a string reference from a ``std::basic_string`` object.
+      \endrst
+     */
+    template<typename Allocator>
+    BasicCStringRef(const std::basic_string<Char, std::char_traits<Char>, Allocator> &s)
+        : data_(s.c_str())
+    {
+    }
+
+    /** Returns the pointer to a C string. */
+    const Char *c_str() const
+    {
+        return data_;
+    }
+};
+
+typedef BasicCStringRef<char> CStringRef;
+typedef BasicCStringRef<wchar_t> WCStringRef;
+
+/** A formatting error such as invalid format string. */
+class FormatError : public std::runtime_error
+{
+public:
+    explicit FormatError(CStringRef message)
+        : std::runtime_error(message.c_str())
+    {
+    }
+    FormatError(const FormatError &ferr)
+        : std::runtime_error(ferr)
+    {
+    }
+    FMT_API ~FormatError() FMT_DTOR_NOEXCEPT FMT_OVERRIDE;
+};
+
+namespace internal {
+
+// MakeUnsigned<T>::Type gives an unsigned type corresponding to integer type T.
+template<typename T>
+struct MakeUnsigned
+{
+    typedef T Type;
+};
+
+#define FMT_SPECIALIZE_MAKE_UNSIGNED(T, U)                                                                                                 \
+    template<>                                                                                                                             \
+    struct MakeUnsigned<T>                                                                                                                 \
+    {                                                                                                                                      \
+        typedef U Type;                                                                                                                    \
+    }
+
+FMT_SPECIALIZE_MAKE_UNSIGNED(char, unsigned char);
+FMT_SPECIALIZE_MAKE_UNSIGNED(signed char, unsigned char);
+FMT_SPECIALIZE_MAKE_UNSIGNED(short, unsigned short);
+FMT_SPECIALIZE_MAKE_UNSIGNED(int, unsigned);
+FMT_SPECIALIZE_MAKE_UNSIGNED(long, unsigned long);
+FMT_SPECIALIZE_MAKE_UNSIGNED(LongLong, ULongLong);
+
+// Casts nonnegative integer to unsigned.
+template<typename Int>
+inline typename MakeUnsigned<Int>::Type to_unsigned(Int value)
+{
+    FMT_ASSERT(value >= 0, "negative value");
+    return static_cast<typename MakeUnsigned<Int>::Type>(value);
+}
+
+// The number of characters to store in the MemoryBuffer object itself
+// to avoid dynamic memory allocation.
+enum
+{
+    INLINE_BUFFER_SIZE = 500
+};
+
+#if FMT_SECURE_SCL
+// Use checked iterator to avoid warnings on MSVC.
+template<typename T>
+inline stdext::checked_array_iterator<T *> make_ptr(T *ptr, std::size_t size)
+{
+    return stdext::checked_array_iterator<T *>(ptr, size);
+}
+#else
+template<typename T>
+inline T *make_ptr(T *ptr, std::size_t)
+{
+    return ptr;
+}
+#endif
+} // namespace internal
+
+/**
+  \rst
+  A buffer supporting a subset of ``std::vector``'s operations.
+  \endrst
+ */
+template<typename T>
+class Buffer
+{
+private:
+    FMT_DISALLOW_COPY_AND_ASSIGN(Buffer);
+
+protected:
+    T *ptr_;
+    std::size_t size_;
+    std::size_t capacity_;
+
+    Buffer(T *ptr = FMT_NULL, std::size_t capacity = 0)
+        : ptr_(ptr)
+        , size_(0)
+        , capacity_(capacity)
+    {
+    }
+
+    /**
+      \rst
+      Increases the buffer capacity to hold at least *size* elements updating
+      ``ptr_`` and ``capacity_``.
+      \endrst
+     */
+    virtual void grow(std::size_t size) = 0;
+
+public:
+    virtual ~Buffer() {}
+
+    /** Returns the size of this buffer. */
+    std::size_t size() const
+    {
+        return size_;
+    }
+
+    /** Returns the capacity of this buffer. */
+    std::size_t capacity() const
+    {
+        return capacity_;
+    }
+
+    /**
+      Resizes the buffer. If T is a POD type new elements may not be initialized.
+     */
+    void resize(std::size_t new_size)
+    {
+        if (new_size > capacity_)
+            grow(new_size);
+        size_ = new_size;
+    }
+
+    /**
+      \rst
+      Reserves space to store at least *capacity* elements.
+      \endrst
+     */
+    void reserve(std::size_t capacity)
+    {
+        if (capacity > capacity_)
+            grow(capacity);
+    }
+
+    void clear() FMT_NOEXCEPT
+    {
+        size_ = 0;
+    }
+
+    void push_back(const T &value)
+    {
+        if (size_ == capacity_)
+            grow(size_ + 1);
+        ptr_[size_++] = value;
+    }
+
+    /** Appends data to the end of the buffer. */
+    template<typename U>
+    void append(const U *begin, const U *end);
+
+    T &operator[](std::size_t index)
+    {
+        return ptr_[index];
+    }
+    const T &operator[](std::size_t index) const
+    {
+        return ptr_[index];
+    }
+};
+
+template<typename T>
+template<typename U>
+void Buffer<T>::append(const U *begin, const U *end)
+{
+    FMT_ASSERT(end >= begin, "negative value");
+    std::size_t new_size = size_ + static_cast<std::size_t>(end - begin);
+    if (new_size > capacity_)
+        grow(new_size);
+    std::uninitialized_copy(begin, end, internal::make_ptr(ptr_, capacity_) + size_);
+    size_ = new_size;
+}
+
+namespace internal {
+
+// A memory buffer for trivially copyable/constructible types with the first
+// SIZE elements stored in the object itself.
+template<typename T, std::size_t SIZE, typename Allocator = std::allocator<T>>
+class MemoryBuffer : private Allocator, public Buffer<T>
+{
+private:
+    T data_[SIZE];
+
+    // Deallocate memory allocated by the buffer.
+    void deallocate()
+    {
+        if (this->ptr_ != data_)
+            Allocator::deallocate(this->ptr_, this->capacity_);
+    }
+
+protected:
+    void grow(std::size_t size) FMT_OVERRIDE;
+
+public:
+    explicit MemoryBuffer(const Allocator &alloc = Allocator())
+        : Allocator(alloc)
+        , Buffer<T>(data_, SIZE)
+    {
+    }
+    ~MemoryBuffer() FMT_OVERRIDE
+    {
+        deallocate();
+    }
+
+#if FMT_USE_RVALUE_REFERENCES
+private:
+    // Move data from other to this buffer.
+    void move(MemoryBuffer &other)
+    {
+        Allocator &this_alloc = *this, &other_alloc = other;
+        this_alloc = std::move(other_alloc);
+        this->size_ = other.size_;
+        this->capacity_ = other.capacity_;
+        if (other.ptr_ == other.data_)
+        {
+            this->ptr_ = data_;
+            std::uninitialized_copy(other.data_, other.data_ + this->size_, make_ptr(data_, this->capacity_));
+        }
+        else
+        {
+            this->ptr_ = other.ptr_;
+            // Set pointer to the inline array so that delete is not called
+            // when deallocating.
+            other.ptr_ = other.data_;
+        }
+    }
+
+public:
+    MemoryBuffer(MemoryBuffer &&other)
+    {
+        move(other);
+    }
+
+    MemoryBuffer &operator=(MemoryBuffer &&other)
+    {
+        assert(this != &other);
+        deallocate();
+        move(other);
+        return *this;
+    }
+#endif
+
+    // Returns a copy of the allocator associated with this buffer.
+    Allocator get_allocator() const
+    {
+        return *this;
+    }
+};
+
+template<typename T, std::size_t SIZE, typename Allocator>
+void MemoryBuffer<T, SIZE, Allocator>::grow(std::size_t size)
+{
+    std::size_t new_capacity = this->capacity_ + this->capacity_ / 2;
+    if (size > new_capacity)
+        new_capacity = size;
+#if FMT_USE_ALLOCATOR_TRAITS
+    T *new_ptr = std::allocator_traits<Allocator>::allocate(*this, new_capacity, FMT_NULL);
+#else
+    T *new_ptr = this->allocate(new_capacity, FMT_NULL);
+#endif
+    // The following code doesn't throw, so the raw pointer above doesn't leak.
+    std::uninitialized_copy(this->ptr_, this->ptr_ + this->size_, make_ptr(new_ptr, new_capacity));
+    std::size_t old_capacity = this->capacity_;
+    T *old_ptr = this->ptr_;
+    this->capacity_ = new_capacity;
+    this->ptr_ = new_ptr;
+    // deallocate may throw (at least in principle), but it doesn't matter since
+    // the buffer already uses the new storage and will deallocate it in case
+    // of exception.
+    if (old_ptr != data_)
+        Allocator::deallocate(old_ptr, old_capacity);
+}
+
+// A fixed-size buffer.
+template<typename Char>
+class FixedBuffer : public fmt::Buffer<Char>
+{
+public:
+    FixedBuffer(Char *array, std::size_t size)
+        : fmt::Buffer<Char>(array, size)
+    {
+    }
+
+protected:
+    FMT_API void grow(std::size_t size) FMT_OVERRIDE;
+};
+
+template<typename Char>
+class BasicCharTraits
+{
+public:
+#if FMT_SECURE_SCL
+    typedef stdext::checked_array_iterator<Char *> CharPtr;
+#else
+    typedef Char *CharPtr;
+#endif
+    static Char cast(int value)
+    {
+        return static_cast<Char>(value);
+    }
+};
+
+template<typename Char>
+class CharTraits;
+
+template<>
+class CharTraits<char> : public BasicCharTraits<char>
+{
+private:
+    // Conversion from wchar_t to char is not allowed.
+    static char convert(wchar_t);
+
+public:
+    static char convert(char value)
+    {
+        return value;
+    }
+
+    // Formats a floating-point number.
+    template<typename T>
+    FMT_API static int format_float(char *buffer, std::size_t size, const char *format, unsigned width, int precision, T value);
+};
+
+#if FMT_USE_EXTERN_TEMPLATES
+extern template int CharTraits<char>::format_float<double>(
+    char *buffer, std::size_t size, const char *format, unsigned width, int precision, double value);
+extern template int CharTraits<char>::format_float<long double>(
+    char *buffer, std::size_t size, const char *format, unsigned width, int precision, long double value);
+#endif
+
+template<>
+class CharTraits<wchar_t> : public BasicCharTraits<wchar_t>
+{
+public:
+    static wchar_t convert(char value)
+    {
+        return value;
+    }
+    static wchar_t convert(wchar_t value)
+    {
+        return value;
+    }
+
+    template<typename T>
+    FMT_API static int format_float(wchar_t *buffer, std::size_t size, const wchar_t *format, unsigned width, int precision, T value);
+};
+
+#if FMT_USE_EXTERN_TEMPLATES
+extern template int CharTraits<wchar_t>::format_float<double>(
+    wchar_t *buffer, std::size_t size, const wchar_t *format, unsigned width, int precision, double value);
+extern template int CharTraits<wchar_t>::format_float<long double>(
+    wchar_t *buffer, std::size_t size, const wchar_t *format, unsigned width, int precision, long double value);
+#endif
+
+// Checks if a number is negative - used to avoid warnings.
+template<bool IsSigned>
+struct SignChecker
+{
+    template<typename T>
+    static bool is_negative(T value)
+    {
+        return value < 0;
+    }
+};
+
+template<>
+struct SignChecker<false>
+{
+    template<typename T>
+    static bool is_negative(T)
+    {
+        return false;
+    }
+};
+
+// Returns true if value is negative, false otherwise.
+// Same as (value < 0) but doesn't produce warnings if T is an unsigned type.
+template<typename T>
+inline bool is_negative(T value)
+{
+    return SignChecker<std::numeric_limits<T>::is_signed>::is_negative(value);
+}
+
+// Selects uint32_t if FitsIn32Bits is true, uint64_t otherwise.
+template<bool FitsIn32Bits>
+struct TypeSelector
+{
+    typedef uint32_t Type;
+};
+
+template<>
+struct TypeSelector<false>
+{
+    typedef uint64_t Type;
+};
+
+template<typename T>
+struct IntTraits
+{
+    // Smallest of uint32_t and uint64_t that is large enough to represent
+    // all values of T.
+    typedef typename TypeSelector<std::numeric_limits<T>::digits <= 32>::Type MainType;
+};
+
+FMT_API FMT_NORETURN void report_unknown_type(char code, const char *type);
+
+// Static data is placed in this class template to allow header-only
+// configuration.
+template<typename T = void>
+struct FMT_API BasicData
+{
+    static const uint32_t POWERS_OF_10_32[];
+    static const uint64_t POWERS_OF_10_64[];
+    static const char DIGITS[];
+};
+
+#if FMT_USE_EXTERN_TEMPLATES
+extern template struct BasicData<void>;
+#endif
+
+typedef BasicData<> Data;
+
+#ifdef FMT_BUILTIN_CLZLL
+// Returns the number of decimal digits in n. Leading zeros are not counted
+// except for n == 0 in which case count_digits returns 1.
+inline unsigned count_digits(uint64_t n)
+{
+    // Based on http://graphics.stanford.edu/~seander/bithacks.html#IntegerLog10
+    // and the benchmark https://github.com/localvoid/cxx-benchmark-count-digits.
+    int t = (64 - FMT_BUILTIN_CLZLL(n | 1)) * 1233 >> 12;
+    return to_unsigned(t) - (n < Data::POWERS_OF_10_64[t]) + 1;
+}
+#else
+// Fallback version of count_digits used when __builtin_clz is not available.
+inline unsigned count_digits(uint64_t n)
+{
+    unsigned count = 1;
+    for (;;)
+    {
+        // Integer division is slow so do it for a group of four digits instead
+        // of for every digit. The idea comes from the talk by Alexandrescu
+        // "Three Optimization Tips for C++". See speed-test for a comparison.
+        if (n < 10)
+            return count;
+        if (n < 100)
+            return count + 1;
+        if (n < 1000)
+            return count + 2;
+        if (n < 10000)
+            return count + 3;
+        n /= 10000u;
+        count += 4;
+    }
+}
+#endif
+
+#ifdef FMT_BUILTIN_CLZ
+// Optional version of count_digits for better performance on 32-bit platforms.
+inline unsigned count_digits(uint32_t n)
+{
+    int t = (32 - FMT_BUILTIN_CLZ(n | 1)) * 1233 >> 12;
+    return to_unsigned(t) - (n < Data::POWERS_OF_10_32[t]) + 1;
+}
+#endif
+
+// A functor that doesn't add a thousands separator.
+struct NoThousandsSep
+{
+    template<typename Char>
+    void operator()(Char *)
+    {
+    }
+};
+
+// A functor that adds a thousands separator.
+class ThousandsSep
+{
+private:
+    fmt::StringRef sep_;
+
+    // Index of a decimal digit with the least significant digit having index 0.
+    unsigned digit_index_;
+
+public:
+    explicit ThousandsSep(fmt::StringRef sep)
+        : sep_(sep)
+        , digit_index_(0)
+    {
+    }
+
+    template<typename Char>
+    void operator()(Char *&buffer)
+    {
+        if (++digit_index_ % 3 != 0)
+            return;
+        buffer -= sep_.size();
+        std::uninitialized_copy(sep_.data(), sep_.data() + sep_.size(), internal::make_ptr(buffer, sep_.size()));
+    }
+};
+
+// Formats a decimal unsigned integer value writing into buffer.
+// thousands_sep is a functor that is called after writing each char to
+// add a thousands separator if necessary.
+template<typename UInt, typename Char, typename ThousandsSep>
+inline void format_decimal(Char *buffer, UInt value, unsigned num_digits, ThousandsSep thousands_sep)
+{
+    buffer += num_digits;
+    while (value >= 100)
+    {
+        // Integer division is slow so do it for a group of two digits instead
+        // of for every digit. The idea comes from the talk by Alexandrescu
+        // "Three Optimization Tips for C++". See speed-test for a comparison.
+        unsigned index = static_cast<unsigned>((value % 100) * 2);
+        value /= 100;
+        *--buffer = Data::DIGITS[index + 1];
+        thousands_sep(buffer);
+        *--buffer = Data::DIGITS[index];
+        thousands_sep(buffer);
+    }
+    if (value < 10)
+    {
+        *--buffer = static_cast<char>('0' + value);
+        return;
+    }
+    unsigned index = static_cast<unsigned>(value * 2);
+    *--buffer = Data::DIGITS[index + 1];
+    thousands_sep(buffer);
+    *--buffer = Data::DIGITS[index];
+}
+
+template<typename UInt, typename Char>
+inline void format_decimal(Char *buffer, UInt value, unsigned num_digits)
+{
+    format_decimal(buffer, value, num_digits, NoThousandsSep());
+    return;
+}
+
+#ifndef _WIN32
+#define FMT_USE_WINDOWS_H 0
+#elif !defined(FMT_USE_WINDOWS_H)
+#define FMT_USE_WINDOWS_H 1
+#endif
+
+// Define FMT_USE_WINDOWS_H to 0 to disable use of windows.h.
+// All the functionality that relies on it will be disabled too.
+#if FMT_USE_WINDOWS_H
+// A converter from UTF-8 to UTF-16.
+// It is only provided for Windows since other systems support UTF-8 natively.
+class UTF8ToUTF16
+{
+private:
+    MemoryBuffer<wchar_t, INLINE_BUFFER_SIZE> buffer_;
+
+public:
+    FMT_API explicit UTF8ToUTF16(StringRef s);
+    operator WStringRef() const
+    {
+        return WStringRef(&buffer_[0], size());
+    }
+    size_t size() const
+    {
+        return buffer_.size() - 1;
+    }
+    const wchar_t *c_str() const
+    {
+        return &buffer_[0];
+    }
+    std::wstring str() const
+    {
+        return std::wstring(&buffer_[0], size());
+    }
+};
+
+// A converter from UTF-16 to UTF-8.
+// It is only provided for Windows since other systems support UTF-8 natively.
+class UTF16ToUTF8
+{
+private:
+    MemoryBuffer<char, INLINE_BUFFER_SIZE> buffer_;
+
+public:
+    UTF16ToUTF8() {}
+    FMT_API explicit UTF16ToUTF8(WStringRef s);
+    operator StringRef() const
+    {
+        return StringRef(&buffer_[0], size());
+    }
+    size_t size() const
+    {
+        return buffer_.size() - 1;
+    }
+    const char *c_str() const
+    {
+        return &buffer_[0];
+    }
+    std::string str() const
+    {
+        return std::string(&buffer_[0], size());
+    }
+
+    // Performs conversion returning a system error code instead of
+    // throwing exception on conversion error. This method may still throw
+    // in case of memory allocation error.
+    FMT_API int convert(WStringRef s);
+};
+
+FMT_API void format_windows_error(fmt::Writer &out, int error_code, fmt::StringRef message) FMT_NOEXCEPT;
+#endif
+
+// A formatting argument value.
+struct Value
+{
+    template<typename Char>
+    struct StringValue
+    {
+        const Char *value;
+        std::size_t size;
+    };
+
+    typedef void (*FormatFunc)(void *formatter, const void *arg, void *format_str_ptr);
+
+    struct CustomValue
+    {
+        const void *value;
+        FormatFunc format;
+    };
+
+    union
+    {
+        int int_value;
+        unsigned uint_value;
+        LongLong long_long_value;
+        ULongLong ulong_long_value;
+        double double_value;
+        long double long_double_value;
+        const void *pointer;
+        StringValue<char> string;
+        StringValue<signed char> sstring;
+        StringValue<unsigned char> ustring;
+        StringValue<wchar_t> wstring;
+        CustomValue custom;
+    };
+
+    enum Type
+    {
+        NONE,
+        NAMED_ARG,
+        // Integer types should go first,
+        INT,
+        UINT,
+        LONG_LONG,
+        ULONG_LONG,
+        BOOL,
+        CHAR,
+        LAST_INTEGER_TYPE = CHAR,
+        // followed by floating-point types.
+        DOUBLE,
+        LONG_DOUBLE,
+        LAST_NUMERIC_TYPE = LONG_DOUBLE,
+        CSTRING,
+        STRING,
+        WSTRING,
+        POINTER,
+        CUSTOM
+    };
+};
+
+// A formatting argument. It is a trivially copyable/constructible type to
+// allow storage in internal::MemoryBuffer.
+struct Arg : Value
+{
+    Type type;
+};
+
+template<typename Char>
+struct NamedArg;
+template<typename Char, typename T>
+struct NamedArgWithType;
+
+template<typename T = void>
+struct Null
+{
+};
+
+// A helper class template to enable or disable overloads taking wide
+// characters and strings in MakeValue.
+template<typename T, typename Char>
+struct WCharHelper
+{
+    typedef Null<T> Supported;
+    typedef T Unsupported;
+};
+
+template<typename T>
+struct WCharHelper<T, wchar_t>
+{
+    typedef T Supported;
+    typedef Null<T> Unsupported;
+};
+
+typedef char Yes[1];
+typedef char No[2];
+
+template<typename T>
+T &get();
+
+// These are non-members to workaround an overload resolution bug in bcc32.
+Yes &convert(fmt::ULongLong);
+No &convert(...);
+
+template<typename T, bool ENABLE_CONVERSION>
+struct ConvertToIntImpl
+{
+    enum
+    {
+        value = ENABLE_CONVERSION
+    };
+};
+
+template<typename T, bool ENABLE_CONVERSION>
+struct ConvertToIntImpl2
+{
+    enum
+    {
+        value = false
+    };
+};
+
+template<typename T>
+struct ConvertToIntImpl2<T, true>
+{
+    enum
+    {
+        // Don't convert numeric types.
+        value = ConvertToIntImpl<T, !std::numeric_limits<T>::is_specialized>::value
+    };
+};
+
+template<typename T>
+struct ConvertToInt
+{
+    enum
+    {
+        enable_conversion = sizeof(fmt::internal::convert(get<T>())) == sizeof(Yes)
+    };
+    enum
+    {
+        value = ConvertToIntImpl2<T, enable_conversion>::value
+    };
+};
+
+#define FMT_DISABLE_CONVERSION_TO_INT(Type)                                                                                                \
+    template<>                                                                                                                             \
+    struct ConvertToInt<Type>                                                                                                              \
+    {                                                                                                                                      \
+        enum                                                                                                                               \
+        {                                                                                                                                  \
+            value = 0                                                                                                                      \
+        };                                                                                                                                 \
+    }
+
+// Silence warnings about convering float to int.
+FMT_DISABLE_CONVERSION_TO_INT(float);
+FMT_DISABLE_CONVERSION_TO_INT(double);
+FMT_DISABLE_CONVERSION_TO_INT(long double);
+
+template<bool B, class T = void>
+struct EnableIf
+{
+};
+
+template<class T>
+struct EnableIf<true, T>
+{
+    typedef T type;
+};
+
+template<bool B, class T, class F>
+struct Conditional
+{
+    typedef T type;
+};
+
+template<class T, class F>
+struct Conditional<false, T, F>
+{
+    typedef F type;
+};
+
+// For bcc32 which doesn't understand ! in template arguments.
+template<bool>
+struct Not
+{
+    enum
+    {
+        value = 0
+    };
+};
+
+template<>
+struct Not<false>
+{
+    enum
+    {
+        value = 1
+    };
+};
+
+template<typename T>
+struct FalseType
+{
+    enum
+    {
+        value = 0
+    };
+};
+
+template<typename T, T>
+struct LConvCheck
+{
+    LConvCheck(int) {}
+};
+
+// Returns the thousands separator for the current locale.
+// We check if ``lconv`` contains ``thousands_sep`` because on Android
+// ``lconv`` is stubbed as an empty struct.
+template<typename LConv>
+inline StringRef thousands_sep(LConv *lc, LConvCheck<char * LConv::*, &LConv::thousands_sep> = 0)
+{
+    return lc->thousands_sep;
+}
+
+inline fmt::StringRef thousands_sep(...)
+{
+    return "";
+}
+
+#define FMT_CONCAT(a, b) a##b
+
+#if FMT_GCC_VERSION >= 303
+#define FMT_UNUSED __attribute__((unused))
+#else
+#define FMT_UNUSED
+#endif
+
+#ifndef FMT_USE_STATIC_ASSERT
+#define FMT_USE_STATIC_ASSERT 0
+#endif
+
+#if FMT_USE_STATIC_ASSERT || FMT_HAS_FEATURE(cxx_static_assert) || (FMT_GCC_VERSION >= 403 && FMT_HAS_GXX_CXX11) || _MSC_VER >= 1600
+#define FMT_STATIC_ASSERT(cond, message) static_assert(cond, message)
+#else
+#define FMT_CONCAT_(a, b) FMT_CONCAT(a, b)
+#define FMT_STATIC_ASSERT(cond, message) typedef int FMT_CONCAT_(Assert, __LINE__)[(cond) ? 1 : -1] FMT_UNUSED
+#endif
+
+template<typename Formatter>
+void format_arg(Formatter &, ...)
+{
+    FMT_STATIC_ASSERT(FalseType<Formatter>::value, "Cannot format argument. To enable the use of ostream "
+                                                   "operator<< include fmt/ostream.h. Otherwise provide "
+                                                   "an overload of format_arg.");
+}
+
+// Makes an Arg object from any type.
+template<typename Formatter>
+class MakeValue : public Arg
+{
+public:
+    typedef typename Formatter::Char Char;
+
+private:
+    // The following two methods are private to disallow formatting of
+    // arbitrary pointers. If you want to output a pointer cast it to
+    // "void *" or "const void *". In particular, this forbids formatting
+    // of "[const] volatile char *" which is printed as bool by iostreams.
+    // Do not implement!
+    template<typename T>
+    MakeValue(const T *value);
+    template<typename T>
+    MakeValue(T *value);
+
+    // The following methods are private to disallow formatting of wide
+    // characters and strings into narrow strings as in
+    //   fmt::format("{}", L"test");
+    // To fix this, use a wide format string: fmt::format(L"{}", L"test").
+#if !FMT_MSC_VER || defined(_NATIVE_WCHAR_T_DEFINED)
+    MakeValue(typename WCharHelper<wchar_t, Char>::Unsupported);
+#endif
+    MakeValue(typename WCharHelper<wchar_t *, Char>::Unsupported);
+    MakeValue(typename WCharHelper<const wchar_t *, Char>::Unsupported);
+    MakeValue(typename WCharHelper<const std::wstring &, Char>::Unsupported);
+#if FMT_HAS_STRING_VIEW
+    MakeValue(typename WCharHelper<const std::wstring_view &, Char>::Unsupported);
+#endif
+    MakeValue(typename WCharHelper<WStringRef, Char>::Unsupported);
+
+    void set_string(StringRef str)
+    {
+        string.value = str.data();
+        string.size = str.size();
+    }
+
+    void set_string(WStringRef str)
+    {
+        wstring.value = str.data();
+        wstring.size = str.size();
+    }
+
+    // Formats an argument of a custom type, such as a user-defined class.
+    template<typename T>
+    static void format_custom_arg(void *formatter, const void *arg, void *format_str_ptr)
+    {
+        format_arg(*static_cast<Formatter *>(formatter), *static_cast<const Char **>(format_str_ptr), *static_cast<const T *>(arg));
+    }
+
+public:
+    MakeValue() {}
+
+#define FMT_MAKE_VALUE_(Type, field, TYPE, rhs)                                                                                            \
+    MakeValue(Type value)                                                                                                                  \
+    {                                                                                                                                      \
+        field = rhs;                                                                                                                       \
+    }                                                                                                                                      \
+    static uint64_t type(Type)                                                                                                             \
+    {                                                                                                                                      \
+        return Arg::TYPE;                                                                                                                  \
+    }
+
+#define FMT_MAKE_VALUE(Type, field, TYPE) FMT_MAKE_VALUE_(Type, field, TYPE, value)
+
+    FMT_MAKE_VALUE(bool, int_value, BOOL)
+    FMT_MAKE_VALUE(short, int_value, INT)
+    FMT_MAKE_VALUE(unsigned short, uint_value, UINT)
+    FMT_MAKE_VALUE(int, int_value, INT)
+    FMT_MAKE_VALUE(unsigned, uint_value, UINT)
+
+    MakeValue(long value)
+    {
+        // To minimize the number of types we need to deal with, long is
+        // translated either to int or to long long depending on its size.
+        if (const_check(sizeof(long) == sizeof(int)))
+            int_value = static_cast<int>(value);
+        else
+            long_long_value = value;
+    }
+    static uint64_t type(long)
+    {
+        return sizeof(long) == sizeof(int) ? Arg::INT : Arg::LONG_LONG;
+    }
+
+    MakeValue(unsigned long value)
+    {
+        if (const_check(sizeof(unsigned long) == sizeof(unsigned)))
+            uint_value = static_cast<unsigned>(value);
+        else
+            ulong_long_value = value;
+    }
+    static uint64_t type(unsigned long)
+    {
+        return sizeof(unsigned long) == sizeof(unsigned) ? Arg::UINT : Arg::ULONG_LONG;
+    }
+
+    FMT_MAKE_VALUE(LongLong, long_long_value, LONG_LONG)
+    FMT_MAKE_VALUE(ULongLong, ulong_long_value, ULONG_LONG)
+    FMT_MAKE_VALUE(float, double_value, DOUBLE)
+    FMT_MAKE_VALUE(double, double_value, DOUBLE)
+    FMT_MAKE_VALUE(long double, long_double_value, LONG_DOUBLE)
+    FMT_MAKE_VALUE(signed char, int_value, INT)
+    FMT_MAKE_VALUE(unsigned char, uint_value, UINT)
+    FMT_MAKE_VALUE(char, int_value, CHAR)
+
+#if __cplusplus >= 201103L
+    template<typename T, typename = typename std::enable_if<std::is_enum<T>::value && ConvertToInt<T>::value>::type>
+    MakeValue(T value)
+    {
+        int_value = value;
+    }
+
+    template<typename T, typename = typename std::enable_if<std::is_enum<T>::value && ConvertToInt<T>::value>::type>
+    static uint64_t type(T)
+    {
+        return Arg::INT;
+    }
+#endif
+
+#if !defined(_MSC_VER) || defined(_NATIVE_WCHAR_T_DEFINED)
+    MakeValue(typename WCharHelper<wchar_t, Char>::Supported value)
+    {
+        int_value = value;
+    }
+    static uint64_t type(wchar_t)
+    {
+        return Arg::CHAR;
+    }
+#endif
+
+#define FMT_MAKE_STR_VALUE(Type, TYPE)                                                                                                     \
+    MakeValue(Type value)                                                                                                                  \
+    {                                                                                                                                      \
+        set_string(value);                                                                                                                 \
+    }                                                                                                                                      \
+    static uint64_t type(Type)                                                                                                             \
+    {                                                                                                                                      \
+        return Arg::TYPE;                                                                                                                  \
+    }
+
+    FMT_MAKE_VALUE(char *, string.value, CSTRING)
+    FMT_MAKE_VALUE(const char *, string.value, CSTRING)
+    FMT_MAKE_VALUE(signed char *, sstring.value, CSTRING)
+    FMT_MAKE_VALUE(const signed char *, sstring.value, CSTRING)
+    FMT_MAKE_VALUE(unsigned char *, ustring.value, CSTRING)
+    FMT_MAKE_VALUE(const unsigned char *, ustring.value, CSTRING)
+    FMT_MAKE_STR_VALUE(const std::string &, STRING)
+#if FMT_HAS_STRING_VIEW
+    FMT_MAKE_STR_VALUE(const std::string_view &, STRING)
+#endif
+    FMT_MAKE_STR_VALUE(StringRef, STRING)
+    FMT_MAKE_VALUE_(CStringRef, string.value, CSTRING, value.c_str())
+
+#define FMT_MAKE_WSTR_VALUE(Type, TYPE)                                                                                                    \
+    MakeValue(typename WCharHelper<Type, Char>::Supported value)                                                                           \
+    {                                                                                                                                      \
+        set_string(value);                                                                                                                 \
+    }                                                                                                                                      \
+    static uint64_t type(Type)                                                                                                             \
+    {                                                                                                                                      \
+        return Arg::TYPE;                                                                                                                  \
+    }
+
+    FMT_MAKE_WSTR_VALUE(wchar_t *, WSTRING)
+    FMT_MAKE_WSTR_VALUE(const wchar_t *, WSTRING)
+    FMT_MAKE_WSTR_VALUE(const std::wstring &, WSTRING)
+#if FMT_HAS_STRING_VIEW
+    FMT_MAKE_WSTR_VALUE(const std::wstring_view &, WSTRING)
+#endif
+    FMT_MAKE_WSTR_VALUE(WStringRef, WSTRING)
+
+    FMT_MAKE_VALUE(void *, pointer, POINTER)
+    FMT_MAKE_VALUE(const void *, pointer, POINTER)
+
+    template<typename T>
+    MakeValue(const T &value, typename EnableIf<Not<ConvertToInt<T>::value>::value, int>::type = 0)
+    {
+        custom.value = &value;
+        custom.format = &format_custom_arg<T>;
+    }
+
+    template<typename T>
+    static typename EnableIf<Not<ConvertToInt<T>::value>::value, uint64_t>::type type(const T &)
+    {
+        return Arg::CUSTOM;
+    }
+
+    // Additional template param `Char_` is needed here because make_type always
+    // uses char.
+    template<typename Char_>
+    MakeValue(const NamedArg<Char_> &value)
+    {
+        pointer = &value;
+    }
+    template<typename Char_, typename T>
+    MakeValue(const NamedArgWithType<Char_, T> &value)
+    {
+        pointer = &value;
+    }
+
+    template<typename Char_>
+    static uint64_t type(const NamedArg<Char_> &)
+    {
+        return Arg::NAMED_ARG;
+    }
+    template<typename Char_, typename T>
+    static uint64_t type(const NamedArgWithType<Char_, T> &)
+    {
+        return Arg::NAMED_ARG;
+    }
+};
+
+template<typename Formatter>
+class MakeArg : public Arg
+{
+public:
+    MakeArg()
+    {
+        type = Arg::NONE;
+    }
+
+    template<typename T>
+    MakeArg(const T &value)
+        : Arg(MakeValue<Formatter>(value))
+    {
+        type = static_cast<Arg::Type>(MakeValue<Formatter>::type(value));
+    }
+};
+
+template<typename Char>
+struct NamedArg : Arg
+{
+    BasicStringRef<Char> name;
+
+    template<typename T>
+    NamedArg(BasicStringRef<Char> argname, const T &value)
+        : Arg(MakeArg<BasicFormatter<Char>>(value))
+        , name(argname)
+    {
+    }
+};
+
+template<typename Char, typename T>
+struct NamedArgWithType : NamedArg<Char>
+{
+    NamedArgWithType(BasicStringRef<Char> argname, const T &value)
+        : NamedArg<Char>(argname, value)
+    {
+    }
+};
+
+class RuntimeError : public std::runtime_error
+{
+protected:
+    RuntimeError()
+        : std::runtime_error("")
+    {
+    }
+    RuntimeError(const RuntimeError &rerr)
+        : std::runtime_error(rerr)
+    {
+    }
+    FMT_API ~RuntimeError() FMT_DTOR_NOEXCEPT FMT_OVERRIDE;
+};
+
+template<typename Char>
+class ArgMap;
+} // namespace internal
+
+/** An argument list. */
+class ArgList
+{
+private:
+    // To reduce compiled code size per formatting function call, types of first
+    // MAX_PACKED_ARGS arguments are passed in the types_ field.
+    uint64_t types_;
+    union
+    {
+        // If the number of arguments is less than MAX_PACKED_ARGS, the argument
+        // values are stored in values_, otherwise they are stored in args_.
+        // This is done to reduce compiled code size as storing larger objects
+        // may require more code (at least on x86-64) even if the same amount of
+        // data is actually copied to stack. It saves ~10% on the bloat test.
+        const internal::Value *values_;
+        const internal::Arg *args_;
+    };
+
+    internal::Arg::Type type(unsigned index) const
+    {
+        return type(types_, index);
+    }
+
+    template<typename Char>
+    friend class internal::ArgMap;
+
+public:
+    // Maximum number of arguments with packed types.
+    enum
+    {
+        MAX_PACKED_ARGS = 16
+    };
+
+    ArgList()
+        : types_(0)
+    {
+    }
+
+    ArgList(ULongLong types, const internal::Value *values)
+        : types_(types)
+        , values_(values)
+    {
+    }
+    ArgList(ULongLong types, const internal::Arg *args)
+        : types_(types)
+        , args_(args)
+    {
+    }
+
+    uint64_t types() const
+    {
+        return types_;
+    }
+
+    /** Returns the argument at specified index. */
+    internal::Arg operator[](unsigned index) const
+    {
+        using internal::Arg;
+        Arg arg;
+        bool use_values = type(MAX_PACKED_ARGS - 1) == Arg::NONE;
+        if (index < MAX_PACKED_ARGS)
+        {
+            Arg::Type arg_type = type(index);
+            internal::Value &val = arg;
+            if (arg_type != Arg::NONE)
+                val = use_values ? values_[index] : args_[index];
+            arg.type = arg_type;
+            return arg;
+        }
+        if (use_values)
+        {
+            // The index is greater than the number of arguments that can be stored
+            // in values, so return a "none" argument.
+            arg.type = Arg::NONE;
+            return arg;
+        }
+        for (unsigned i = MAX_PACKED_ARGS; i <= index; ++i)
+        {
+            if (args_[i].type == Arg::NONE)
+                return args_[i];
+        }
+        return args_[index];
+    }
+
+    static internal::Arg::Type type(uint64_t types, unsigned index)
+    {
+        unsigned shift = index * 4;
+        uint64_t mask = 0xf;
+        return static_cast<internal::Arg::Type>((types & (mask << shift)) >> shift);
+    }
+};
+
+#define FMT_DISPATCH(call) static_cast<Impl *>(this)->call
+
+/**
+  \rst
+  An argument visitor based on the `curiously recurring template pattern
+  <http://en.wikipedia.org/wiki/Curiously_recurring_template_pattern>`_.
+
+  To use `~fmt::ArgVisitor` define a subclass that implements some or all of the
+  visit methods with the same signatures as the methods in `~fmt::ArgVisitor`,
+  for example, `~fmt::ArgVisitor::visit_int()`.
+  Pass the subclass as the *Impl* template parameter. Then calling
+  `~fmt::ArgVisitor::visit` for some argument will dispatch to a visit method
+  specific to the argument type. For example, if the argument type is
+  ``double`` then the `~fmt::ArgVisitor::visit_double()` method of a subclass
+  will be called. If the subclass doesn't contain a method with this signature,
+  then a corresponding method of `~fmt::ArgVisitor` will be called.
+
+  **Example**::
+
+    class MyArgVisitor : public fmt::ArgVisitor<MyArgVisitor, void> {
+     public:
+      void visit_int(int value) { fmt::print("{}", value); }
+      void visit_double(double value) { fmt::print("{}", value ); }
+    };
+  \endrst
+ */
+template<typename Impl, typename Result>
+class ArgVisitor
+{
+private:
+    typedef internal::Arg Arg;
+
+public:
+    void report_unhandled_arg() {}
+
+    Result visit_unhandled_arg()
+    {
+        FMT_DISPATCH(report_unhandled_arg());
+        return Result();
+    }
+
+    /** Visits an ``int`` argument. **/
+    Result visit_int(int value)
+    {
+        return FMT_DISPATCH(visit_any_int(value));
+    }
+
+    /** Visits a ``long long`` argument. **/
+    Result visit_long_long(LongLong value)
+    {
+        return FMT_DISPATCH(visit_any_int(value));
+    }
+
+    /** Visits an ``unsigned`` argument. **/
+    Result visit_uint(unsigned value)
+    {
+        return FMT_DISPATCH(visit_any_int(value));
+    }
+
+    /** Visits an ``unsigned long long`` argument. **/
+    Result visit_ulong_long(ULongLong value)
+    {
+        return FMT_DISPATCH(visit_any_int(value));
+    }
+
+    /** Visits a ``bool`` argument. **/
+    Result visit_bool(bool value)
+    {
+        return FMT_DISPATCH(visit_any_int(value));
+    }
+
+    /** Visits a ``char`` or ``wchar_t`` argument. **/
+    Result visit_char(int value)
+    {
+        return FMT_DISPATCH(visit_any_int(value));
+    }
+
+    /** Visits an argument of any integral type. **/
+    template<typename T>
+    Result visit_any_int(T)
+    {
+        return FMT_DISPATCH(visit_unhandled_arg());
+    }
+
+    /** Visits a ``double`` argument. **/
+    Result visit_double(double value)
+    {
+        return FMT_DISPATCH(visit_any_double(value));
+    }
+
+    /** Visits a ``long double`` argument. **/
+    Result visit_long_double(long double value)
+    {
+        return FMT_DISPATCH(visit_any_double(value));
+    }
+
+    /** Visits a ``double`` or ``long double`` argument. **/
+    template<typename T>
+    Result visit_any_double(T)
+    {
+        return FMT_DISPATCH(visit_unhandled_arg());
+    }
+
+    /** Visits a null-terminated C string (``const char *``) argument. **/
+    Result visit_cstring(const char *)
+    {
+        return FMT_DISPATCH(visit_unhandled_arg());
+    }
+
+    /** Visits a string argument. **/
+    Result visit_string(Arg::StringValue<char>)
+    {
+        return FMT_DISPATCH(visit_unhandled_arg());
+    }
+
+    /** Visits a wide string argument. **/
+    Result visit_wstring(Arg::StringValue<wchar_t>)
+    {
+        return FMT_DISPATCH(visit_unhandled_arg());
+    }
+
+    /** Visits a pointer argument. **/
+    Result visit_pointer(const void *)
+    {
+        return FMT_DISPATCH(visit_unhandled_arg());
+    }
+
+    /** Visits an argument of a custom (user-defined) type. **/
+    Result visit_custom(Arg::CustomValue)
+    {
+        return FMT_DISPATCH(visit_unhandled_arg());
+    }
+
+    /**
+      \rst
+      Visits an argument dispatching to the appropriate visit method based on
+      the argument type. For example, if the argument type is ``double`` then
+      the `~fmt::ArgVisitor::visit_double()` method of the *Impl* class will be
+      called.
+      \endrst
+     */
+    Result visit(const Arg &arg)
+    {
+        switch (arg.type)
+        {
+        case Arg::NONE:
+        case Arg::NAMED_ARG:
+            FMT_ASSERT(false, "invalid argument type");
+            break;
+        case Arg::INT:
+            return FMT_DISPATCH(visit_int(arg.int_value));
+        case Arg::UINT:
+            return FMT_DISPATCH(visit_uint(arg.uint_value));
+        case Arg::LONG_LONG:
+            return FMT_DISPATCH(visit_long_long(arg.long_long_value));
+        case Arg::ULONG_LONG:
+            return FMT_DISPATCH(visit_ulong_long(arg.ulong_long_value));
+        case Arg::BOOL:
+            return FMT_DISPATCH(visit_bool(arg.int_value != 0));
+        case Arg::CHAR:
+            return FMT_DISPATCH(visit_char(arg.int_value));
+        case Arg::DOUBLE:
+            return FMT_DISPATCH(visit_double(arg.double_value));
+        case Arg::LONG_DOUBLE:
+            return FMT_DISPATCH(visit_long_double(arg.long_double_value));
+        case Arg::CSTRING:
+            return FMT_DISPATCH(visit_cstring(arg.string.value));
+        case Arg::STRING:
+            return FMT_DISPATCH(visit_string(arg.string));
+        case Arg::WSTRING:
+            return FMT_DISPATCH(visit_wstring(arg.wstring));
+        case Arg::POINTER:
+            return FMT_DISPATCH(visit_pointer(arg.pointer));
+        case Arg::CUSTOM:
+            return FMT_DISPATCH(visit_custom(arg.custom));
+        }
+        return Result();
+    }
+};
+
+enum Alignment
+{
+    ALIGN_DEFAULT,
+    ALIGN_LEFT,
+    ALIGN_RIGHT,
+    ALIGN_CENTER,
+    ALIGN_NUMERIC
+};
+
+// Flags.
+enum
+{
+    SIGN_FLAG = 1,
+    PLUS_FLAG = 2,
+    MINUS_FLAG = 4,
+    HASH_FLAG = 8,
+    CHAR_FLAG = 0x10 // Argument has char type - used in error reporting.
+};
+
+// An empty format specifier.
+struct EmptySpec
+{
+};
+
+// A type specifier.
+template<char TYPE>
+struct TypeSpec : EmptySpec
+{
+    Alignment align() const
+    {
+        return ALIGN_DEFAULT;
+    }
+    unsigned width() const
+    {
+        return 0;
+    }
+    int precision() const
+    {
+        return -1;
+    }
+    bool flag(unsigned) const
+    {
+        return false;
+    }
+    char type() const
+    {
+        return TYPE;
+    }
+    char type_prefix() const
+    {
+        return TYPE;
+    }
+    char fill() const
+    {
+        return ' ';
+    }
+};
+
+// A width specifier.
+struct WidthSpec
+{
+    unsigned width_;
+    // Fill is always wchar_t and cast to char if necessary to avoid having
+    // two specialization of WidthSpec and its subclasses.
+    wchar_t fill_;
+
+    WidthSpec(unsigned width, wchar_t fill)
+        : width_(width)
+        , fill_(fill)
+    {
+    }
+
+    unsigned width() const
+    {
+        return width_;
+    }
+    wchar_t fill() const
+    {
+        return fill_;
+    }
+};
+
+// An alignment specifier.
+struct AlignSpec : WidthSpec
+{
+    Alignment align_;
+
+    AlignSpec(unsigned width, wchar_t fill, Alignment align = ALIGN_DEFAULT)
+        : WidthSpec(width, fill)
+        , align_(align)
+    {
+    }
+
+    Alignment align() const
+    {
+        return align_;
+    }
+
+    int precision() const
+    {
+        return -1;
+    }
+};
+
+// An alignment and type specifier.
+template<char TYPE>
+struct AlignTypeSpec : AlignSpec
+{
+    AlignTypeSpec(unsigned width, wchar_t fill)
+        : AlignSpec(width, fill)
+    {
+    }
+
+    bool flag(unsigned) const
+    {
+        return false;
+    }
+    char type() const
+    {
+        return TYPE;
+    }
+    char type_prefix() const
+    {
+        return TYPE;
+    }
+};
+
+// A full format specifier.
+struct FormatSpec : AlignSpec
+{
+    unsigned flags_;
+    int precision_;
+    char type_;
+
+    FormatSpec(unsigned width = 0, char type = 0, wchar_t fill = ' ')
+        : AlignSpec(width, fill)
+        , flags_(0)
+        , precision_(-1)
+        , type_(type)
+    {
+    }
+
+    bool flag(unsigned f) const
+    {
+        return (flags_ & f) != 0;
+    }
+    int precision() const
+    {
+        return precision_;
+    }
+    char type() const
+    {
+        return type_;
+    }
+    char type_prefix() const
+    {
+        return type_;
+    }
+};
+
+// An integer format specifier.
+template<typename T, typename SpecT = TypeSpec<0>, typename Char = char>
+class IntFormatSpec : public SpecT
+{
+private:
+    T value_;
+
+public:
+    IntFormatSpec(T val, const SpecT &spec = SpecT())
+        : SpecT(spec)
+        , value_(val)
+    {
+    }
+
+    T value() const
+    {
+        return value_;
+    }
+};
+
+// A string format specifier.
+template<typename Char>
+class StrFormatSpec : public AlignSpec
+{
+private:
+    const Char *str_;
+
+public:
+    template<typename FillChar>
+    StrFormatSpec(const Char *str, unsigned width, FillChar fill)
+        : AlignSpec(width, fill)
+        , str_(str)
+    {
+        internal::CharTraits<Char>::convert(FillChar());
+    }
+
+    const Char *str() const
+    {
+        return str_;
+    }
+};
+
+/**
+  Returns an integer format specifier to format the value in base 2.
+ */
+IntFormatSpec<int, TypeSpec<'b'>> bin(int value);
+
+/**
+  Returns an integer format specifier to format the value in base 8.
+ */
+IntFormatSpec<int, TypeSpec<'o'>> oct(int value);
+
+/**
+  Returns an integer format specifier to format the value in base 16 using
+  lower-case letters for the digits above 9.
+ */
+IntFormatSpec<int, TypeSpec<'x'>> hex(int value);
+
+/**
+  Returns an integer formatter format specifier to format in base 16 using
+  upper-case letters for the digits above 9.
+ */
+IntFormatSpec<int, TypeSpec<'X'>> hexu(int value);
+
+/**
+  \rst
+  Returns an integer format specifier to pad the formatted argument with the
+  fill character to the specified width using the default (right) numeric
+  alignment.
+
+  **Example**::
+
+    MemoryWriter out;
+    out << pad(hex(0xcafe), 8, '0');
+    // out.str() == "0000cafe"
+
+  \endrst
+ */
+template<char TYPE_CODE, typename Char>
+IntFormatSpec<int, AlignTypeSpec<TYPE_CODE>, Char> pad(int value, unsigned width, Char fill = ' ');
+
+#define FMT_DEFINE_INT_FORMATTERS(TYPE)                                                                                                    \
+    inline IntFormatSpec<TYPE, TypeSpec<'b'>> bin(TYPE value)                                                                              \
+    {                                                                                                                                      \
+        return IntFormatSpec<TYPE, TypeSpec<'b'>>(value, TypeSpec<'b'>());                                                                 \
+    }                                                                                                                                      \
+                                                                                                                                           \
+    inline IntFormatSpec<TYPE, TypeSpec<'o'>> oct(TYPE value)                                                                              \
+    {                                                                                                                                      \
+        return IntFormatSpec<TYPE, TypeSpec<'o'>>(value, TypeSpec<'o'>());                                                                 \
+    }                                                                                                                                      \
+                                                                                                                                           \
+    inline IntFormatSpec<TYPE, TypeSpec<'x'>> hex(TYPE value)                                                                              \
+    {                                                                                                                                      \
+        return IntFormatSpec<TYPE, TypeSpec<'x'>>(value, TypeSpec<'x'>());                                                                 \
+    }                                                                                                                                      \
+                                                                                                                                           \
+    inline IntFormatSpec<TYPE, TypeSpec<'X'>> hexu(TYPE value)                                                                             \
+    {                                                                                                                                      \
+        return IntFormatSpec<TYPE, TypeSpec<'X'>>(value, TypeSpec<'X'>());                                                                 \
+    }                                                                                                                                      \
+                                                                                                                                           \
+    template<char TYPE_CODE>                                                                                                               \
+    inline IntFormatSpec<TYPE, AlignTypeSpec<TYPE_CODE>> pad(IntFormatSpec<TYPE, TypeSpec<TYPE_CODE>> f, unsigned width)                   \
+    {                                                                                                                                      \
+        return IntFormatSpec<TYPE, AlignTypeSpec<TYPE_CODE>>(f.value(), AlignTypeSpec<TYPE_CODE>(width, ' '));                             \
+    }                                                                                                                                      \
+                                                                                                                                           \
+    /* For compatibility with older compilers we provide two overloads for pad, */                                                         \
+    /* one that takes a fill character and one that doesn't. In the future this */                                                         \
+    /* can be replaced with one overload making the template argument Char      */                                                         \
+    /* default to char (C++11). */                                                                                                         \
+    template<char TYPE_CODE, typename Char>                                                                                                \
+    inline IntFormatSpec<TYPE, AlignTypeSpec<TYPE_CODE>, Char> pad(                                                                        \
+        IntFormatSpec<TYPE, TypeSpec<TYPE_CODE>, Char> f, unsigned width, Char fill)                                                       \
+    {                                                                                                                                      \
+        return IntFormatSpec<TYPE, AlignTypeSpec<TYPE_CODE>, Char>(f.value(), AlignTypeSpec<TYPE_CODE>(width, fill));                      \
+    }                                                                                                                                      \
+                                                                                                                                           \
+    inline IntFormatSpec<TYPE, AlignTypeSpec<0>> pad(TYPE value, unsigned width)                                                           \
+    {                                                                                                                                      \
+        return IntFormatSpec<TYPE, AlignTypeSpec<0>>(value, AlignTypeSpec<0>(width, ' '));                                                 \
+    }                                                                                                                                      \
+                                                                                                                                           \
+    template<typename Char>                                                                                                                \
+    inline IntFormatSpec<TYPE, AlignTypeSpec<0>, Char> pad(TYPE value, unsigned width, Char fill)                                          \
+    {                                                                                                                                      \
+        return IntFormatSpec<TYPE, AlignTypeSpec<0>, Char>(value, AlignTypeSpec<0>(width, fill));                                          \
+    }
+
+FMT_DEFINE_INT_FORMATTERS(int)
+FMT_DEFINE_INT_FORMATTERS(long)
+FMT_DEFINE_INT_FORMATTERS(unsigned)
+FMT_DEFINE_INT_FORMATTERS(unsigned long)
+FMT_DEFINE_INT_FORMATTERS(LongLong)
+FMT_DEFINE_INT_FORMATTERS(ULongLong)
+
+/**
+  \rst
+  Returns a string formatter that pads the formatted argument with the fill
+  character to the specified width using the default (left) string alignment.
+
+  **Example**::
+
+    std::string s = str(MemoryWriter() << pad("abc", 8));
+    // s == "abc     "
+
+  \endrst
+ */
+template<typename Char>
+inline StrFormatSpec<Char> pad(const Char *str, unsigned width, Char fill = ' ')
+{
+    return StrFormatSpec<Char>(str, width, fill);
+}
+
+inline StrFormatSpec<wchar_t> pad(const wchar_t *str, unsigned width, char fill = ' ')
+{
+    return StrFormatSpec<wchar_t>(str, width, fill);
+}
+
+namespace internal {
+
+template<typename Char>
+class ArgMap
+{
+private:
+    typedef std::vector<std::pair<fmt::BasicStringRef<Char>, internal::Arg>> MapType;
+    typedef typename MapType::value_type Pair;
+
+    MapType map_;
+
+public:
+    void init(const ArgList &args);
+
+    const internal::Arg *find(const fmt::BasicStringRef<Char> &name) const
+    {
+        // The list is unsorted, so just return the first matching name.
+        for (typename MapType::const_iterator it = map_.begin(), end = map_.end(); it != end; ++it)
+        {
+            if (it->first == name)
+                return &it->second;
+        }
+        return FMT_NULL;
+    }
+};
+
+template<typename Char>
+void ArgMap<Char>::init(const ArgList &args)
+{
+    if (!map_.empty())
+        return;
+    typedef internal::NamedArg<Char> NamedArg;
+    const NamedArg *named_arg = FMT_NULL;
+    bool use_values = args.type(ArgList::MAX_PACKED_ARGS - 1) == internal::Arg::NONE;
+    if (use_values)
+    {
+        for (unsigned i = 0; /*nothing*/; ++i)
+        {
+            internal::Arg::Type arg_type = args.type(i);
+            switch (arg_type)
+            {
+            case internal::Arg::NONE:
+                return;
+            case internal::Arg::NAMED_ARG:
+                named_arg = static_cast<const NamedArg *>(args.values_[i].pointer);
+                map_.push_back(Pair(named_arg->name, *named_arg));
+                break;
+            default:
+                /*nothing*/
+                ;
+            }
+        }
+        return;
+    }
+    for (unsigned i = 0; i != ArgList::MAX_PACKED_ARGS; ++i)
+    {
+        internal::Arg::Type arg_type = args.type(i);
+        if (arg_type == internal::Arg::NAMED_ARG)
+        {
+            named_arg = static_cast<const NamedArg *>(args.args_[i].pointer);
+            map_.push_back(Pair(named_arg->name, *named_arg));
+        }
+    }
+    for (unsigned i = ArgList::MAX_PACKED_ARGS; /*nothing*/; ++i)
+    {
+        switch (args.args_[i].type)
+        {
+        case internal::Arg::NONE:
+            return;
+        case internal::Arg::NAMED_ARG:
+            named_arg = static_cast<const NamedArg *>(args.args_[i].pointer);
+            map_.push_back(Pair(named_arg->name, *named_arg));
+            break;
+        default:
+            /*nothing*/
+            ;
+        }
+    }
+}
+
+template<typename Impl, typename Char, typename Spec = fmt::FormatSpec>
+class ArgFormatterBase : public ArgVisitor<Impl, void>
+{
+private:
+    BasicWriter<Char> &writer_;
+    Spec &spec_;
+
+    FMT_DISALLOW_COPY_AND_ASSIGN(ArgFormatterBase);
+
+    void write_pointer(const void *p)
+    {
+        spec_.flags_ = HASH_FLAG;
+        spec_.type_ = 'x';
+        writer_.write_int(reinterpret_cast<uintptr_t>(p), spec_);
+    }
+
+    // workaround MSVC two-phase lookup issue
+    typedef internal::Arg Arg;
+
+protected:
+    BasicWriter<Char> &writer()
+    {
+        return writer_;
+    }
+    Spec &spec()
+    {
+        return spec_;
+    }
+
+    void write(bool value)
+    {
+        const char *str_value = value ? "true" : "false";
+        Arg::StringValue<char> str = {str_value, std::strlen(str_value)};
+        writer_.write_str(str, spec_);
+    }
+
+    void write(const char *value)
+    {
+        Arg::StringValue<char> str = {value, value ? std::strlen(value) : 0};
+        writer_.write_str(str, spec_);
+    }
+
+public:
+    typedef Spec SpecType;
+
+    ArgFormatterBase(BasicWriter<Char> &w, Spec &s)
+        : writer_(w)
+        , spec_(s)
+    {
+    }
+
+    template<typename T>
+    void visit_any_int(T value)
+    {
+        writer_.write_int(value, spec_);
+    }
+
+    template<typename T>
+    void visit_any_double(T value)
+    {
+        writer_.write_double(value, spec_);
+    }
+
+    void visit_bool(bool value)
+    {
+        if (spec_.type_)
+        {
+            visit_any_int(value);
+            return;
+        }
+        write(value);
+    }
+
+    void visit_char(int value)
+    {
+        if (spec_.type_ && spec_.type_ != 'c')
+        {
+            spec_.flags_ |= CHAR_FLAG;
+            writer_.write_int(value, spec_);
+            return;
+        }
+        if (spec_.align_ == ALIGN_NUMERIC || spec_.flags_ != 0)
+            FMT_THROW(FormatError("invalid format specifier for char"));
+        typedef typename BasicWriter<Char>::CharPtr CharPtr;
+        Char fill = internal::CharTraits<Char>::cast(spec_.fill());
+        CharPtr out = CharPtr();
+        const unsigned CHAR_SIZE = 1;
+        if (spec_.width_ > CHAR_SIZE)
+        {
+            out = writer_.grow_buffer(spec_.width_);
+            if (spec_.align_ == ALIGN_RIGHT)
+            {
+                std::uninitialized_fill_n(out, spec_.width_ - CHAR_SIZE, fill);
+                out += spec_.width_ - CHAR_SIZE;
+            }
+            else if (spec_.align_ == ALIGN_CENTER)
+            {
+                out = writer_.fill_padding(out, spec_.width_, internal::const_check(CHAR_SIZE), fill);
+            }
+            else
+            {
+                std::uninitialized_fill_n(out + CHAR_SIZE, spec_.width_ - CHAR_SIZE, fill);
+            }
+        }
+        else
+        {
+            out = writer_.grow_buffer(CHAR_SIZE);
+        }
+        *out = internal::CharTraits<Char>::cast(value);
+    }
+
+    void visit_cstring(const char *value)
+    {
+        if (spec_.type_ == 'p')
+            return write_pointer(value);
+        write(value);
+    }
+
+    // Qualification with "internal" here and below is a workaround for nvcc.
+    void visit_string(internal::Arg::StringValue<char> value)
+    {
+        writer_.write_str(value, spec_);
+    }
+
+    using ArgVisitor<Impl, void>::visit_wstring;
+
+    void visit_wstring(internal::Arg::StringValue<Char> value)
+    {
+        writer_.write_str(value, spec_);
+    }
+
+    void visit_pointer(const void *value)
+    {
+        if (spec_.type_ && spec_.type_ != 'p')
+            report_unknown_type(spec_.type_, "pointer");
+        write_pointer(value);
+    }
+};
+
+class FormatterBase
+{
+private:
+    ArgList args_;
+    int next_arg_index_;
+
+    // Returns the argument with specified index.
+    FMT_API Arg do_get_arg(unsigned arg_index, const char *&error);
+
+protected:
+    const ArgList &args() const
+    {
+        return args_;
+    }
+
+    explicit FormatterBase(const ArgList &args)
+    {
+        args_ = args;
+        next_arg_index_ = 0;
+    }
+
+    // Returns the next argument.
+    Arg next_arg(const char *&error)
+    {
+        if (next_arg_index_ >= 0)
+            return do_get_arg(internal::to_unsigned(next_arg_index_++), error);
+        error = "cannot switch from manual to automatic argument indexing";
+        return Arg();
+    }
+
+    // Checks if manual indexing is used and returns the argument with
+    // specified index.
+    Arg get_arg(unsigned arg_index, const char *&error)
+    {
+        return check_no_auto_index(error) ? do_get_arg(arg_index, error) : Arg();
+    }
+
+    bool check_no_auto_index(const char *&error)
+    {
+        if (next_arg_index_ > 0)
+        {
+            error = "cannot switch from automatic to manual argument indexing";
+            return false;
+        }
+        next_arg_index_ = -1;
+        return true;
+    }
+
+    template<typename Char>
+    void write(BasicWriter<Char> &w, const Char *start, const Char *end)
+    {
+        if (start != end)
+            w << BasicStringRef<Char>(start, internal::to_unsigned(end - start));
+    }
+};
+} // namespace internal
+
+/**
+  \rst
+  An argument formatter based on the `curiously recurring template pattern
+  <http://en.wikipedia.org/wiki/Curiously_recurring_template_pattern>`_.
+
+  To use `~fmt::BasicArgFormatter` define a subclass that implements some or
+  all of the visit methods with the same signatures as the methods in
+  `~fmt::ArgVisitor`, for example, `~fmt::ArgVisitor::visit_int()`.
+  Pass the subclass as the *Impl* template parameter. When a formatting
+  function processes an argument, it will dispatch to a visit method
+  specific to the argument type. For example, if the argument type is
+  ``double`` then the `~fmt::ArgVisitor::visit_double()` method of a subclass
+  will be called. If the subclass doesn't contain a method with this signature,
+  then a corresponding method of `~fmt::BasicArgFormatter` or its superclass
+  will be called.
+  \endrst
+ */
+template<typename Impl, typename Char, typename Spec = fmt::FormatSpec>
+class BasicArgFormatter : public internal::ArgFormatterBase<Impl, Char, Spec>
+{
+private:
+    BasicFormatter<Char, Impl> &formatter_;
+    const Char *format_;
+
+public:
+    /**
+      \rst
+      Constructs an argument formatter object.
+      *formatter* is a reference to the main formatter object, *spec* contains
+      format specifier information for standard argument types, and *fmt* points
+      to the part of the format string being parsed for custom argument types.
+      \endrst
+     */
+    BasicArgFormatter(BasicFormatter<Char, Impl> &formatter, Spec &spec, const Char *fmt)
+        : internal::ArgFormatterBase<Impl, Char, Spec>(formatter.writer(), spec)
+        , formatter_(formatter)
+        , format_(fmt)
+    {
+    }
+
+    /** Formats an argument of a custom (user-defined) type. */
+    void visit_custom(internal::Arg::CustomValue c)
+    {
+        c.format(&formatter_, c.value, &format_);
+    }
+};
+
+/** The default argument formatter. */
+template<typename Char>
+class ArgFormatter : public BasicArgFormatter<ArgFormatter<Char>, Char, FormatSpec>
+{
+public:
+    /** Constructs an argument formatter object. */
+    ArgFormatter(BasicFormatter<Char> &formatter, FormatSpec &spec, const Char *fmt)
+        : BasicArgFormatter<ArgFormatter<Char>, Char, FormatSpec>(formatter, spec, fmt)
+    {
+    }
+};
+
+/** This template formats data and writes the output to a writer. */
+template<typename CharType, typename ArgFormatter>
+class BasicFormatter : private internal::FormatterBase
+{
+public:
+    /** The character type for the output. */
+    typedef CharType Char;
+
+private:
+    BasicWriter<Char> &writer_;
+    internal::ArgMap<Char> map_;
+
+    FMT_DISALLOW_COPY_AND_ASSIGN(BasicFormatter);
+
+    using internal::FormatterBase::get_arg;
+
+    // Checks if manual indexing is used and returns the argument with
+    // specified name.
+    internal::Arg get_arg(BasicStringRef<Char> arg_name, const char *&error);
+
+    // Parses argument index and returns corresponding argument.
+    internal::Arg parse_arg_index(const Char *&s);
+
+    // Parses argument name and returns corresponding argument.
+    internal::Arg parse_arg_name(const Char *&s);
+
+public:
+    /**
+     \rst
+     Constructs a ``BasicFormatter`` object. References to the arguments and
+     the writer are stored in the formatter object so make sure they have
+     appropriate lifetimes.
+     \endrst
+     */
+    BasicFormatter(const ArgList &args, BasicWriter<Char> &w)
+        : internal::FormatterBase(args)
+        , writer_(w)
+    {
+    }
+
+    /** Returns a reference to the writer associated with this formatter. */
+    BasicWriter<Char> &writer()
+    {
+        return writer_;
+    }
+
+    /** Formats stored arguments and writes the output to the writer. */
+    void format(BasicCStringRef<Char> format_str);
+
+    // Formats a single argument and advances format_str, a format string pointer.
+    const Char *format(const Char *&format_str, const internal::Arg &arg);
+};
+
+// Generates a comma-separated list with results of applying f to
+// numbers 0..n-1.
+#define FMT_GEN(n, f) FMT_GEN##n(f)
+#define FMT_GEN1(f) f(0)
+#define FMT_GEN2(f) FMT_GEN1(f), f(1)
+#define FMT_GEN3(f) FMT_GEN2(f), f(2)
+#define FMT_GEN4(f) FMT_GEN3(f), f(3)
+#define FMT_GEN5(f) FMT_GEN4(f), f(4)
+#define FMT_GEN6(f) FMT_GEN5(f), f(5)
+#define FMT_GEN7(f) FMT_GEN6(f), f(6)
+#define FMT_GEN8(f) FMT_GEN7(f), f(7)
+#define FMT_GEN9(f) FMT_GEN8(f), f(8)
+#define FMT_GEN10(f) FMT_GEN9(f), f(9)
+#define FMT_GEN11(f) FMT_GEN10(f), f(10)
+#define FMT_GEN12(f) FMT_GEN11(f), f(11)
+#define FMT_GEN13(f) FMT_GEN12(f), f(12)
+#define FMT_GEN14(f) FMT_GEN13(f), f(13)
+#define FMT_GEN15(f) FMT_GEN14(f), f(14)
+
+namespace internal {
+inline uint64_t make_type()
+{
+    return 0;
+}
+
+template<typename T>
+inline uint64_t make_type(const T &arg)
+{
+    return MakeValue<BasicFormatter<char>>::type(arg);
+}
+
+template<std::size_t N, bool /*IsPacked*/ = (N < ArgList::MAX_PACKED_ARGS)>
+struct ArgArray;
+
+template<std::size_t N>
+struct ArgArray<N, true /*IsPacked*/>
+{
+    // '+' is used to silence GCC -Wduplicated-branches warning.
+    typedef Value Type[N > 0 ? N : +1];
+
+    template<typename Formatter, typename T>
+    static Value make(const T &value)
+    {
+#ifdef __clang__
+        Value result = MakeValue<Formatter>(value);
+        // Workaround a bug in Apple LLVM version 4.2 (clang-425.0.28) of clang:
+        // https://github.com/fmtlib/fmt/issues/276
+        (void)result.custom.format;
+        return result;
+#else
+        return MakeValue<Formatter>(value);
+#endif
+    }
+};
+
+template<std::size_t N>
+struct ArgArray<N, false /*IsPacked*/>
+{
+    typedef Arg Type[N + 1]; // +1 for the list end Arg::NONE
+
+    template<typename Formatter, typename T>
+    static Arg make(const T &value)
+    {
+        return MakeArg<Formatter>(value);
+    }
+};
+
+#if FMT_USE_VARIADIC_TEMPLATES
+template<typename Arg, typename... Args>
+inline uint64_t make_type(const Arg &first, const Args &... tail)
+{
+    return make_type(first) | (make_type(tail...) << 4);
+}
+
+#else
+
+struct ArgType
+{
+    uint64_t type;
+
+    ArgType()
+        : type(0)
+    {
+    }
+
+    template<typename T>
+    ArgType(const T &arg)
+        : type(make_type(arg))
+    {
+    }
+};
+
+#define FMT_ARG_TYPE_DEFAULT(n) ArgType t##n = ArgType()
+
+inline uint64_t make_type(FMT_GEN15(FMT_ARG_TYPE_DEFAULT))
+{
+    return t0.type | (t1.type << 4) | (t2.type << 8) | (t3.type << 12) | (t4.type << 16) | (t5.type << 20) | (t6.type << 24) |
+           (t7.type << 28) | (t8.type << 32) | (t9.type << 36) | (t10.type << 40) | (t11.type << 44) | (t12.type << 48) | (t13.type << 52) |
+           (t14.type << 56);
+}
+#endif
+} // namespace internal
+
+#define FMT_MAKE_TEMPLATE_ARG(n) typename T##n
+#define FMT_MAKE_ARG_TYPE(n) T##n
+#define FMT_MAKE_ARG(n) const T##n &v##n
+#define FMT_ASSIGN_char(n) arr[n] = fmt::internal::MakeValue<fmt::BasicFormatter<char>>(v##n)
+#define FMT_ASSIGN_wchar_t(n) arr[n] = fmt::internal::MakeValue<fmt::BasicFormatter<wchar_t>>(v##n)
+
+#if FMT_USE_VARIADIC_TEMPLATES
+// Defines a variadic function returning void.
+#define FMT_VARIADIC_VOID(func, arg_type)                                                                                                  \
+    template<typename... Args>                                                                                                             \
+    void func(arg_type arg0, const Args &... args)                                                                                         \
+    {                                                                                                                                      \
+        typedef fmt::internal::ArgArray<sizeof...(Args)> ArgArray;                                                                         \
+        typename ArgArray::Type array{ArgArray::template make<fmt::BasicFormatter<Char>>(args)...};                                        \
+        func(arg0, fmt::ArgList(fmt::internal::make_type(args...), array));                                                                \
+    }
+
+// Defines a variadic constructor.
+#define FMT_VARIADIC_CTOR(ctor, func, arg0_type, arg1_type)                                                                                \
+    template<typename... Args>                                                                                                             \
+    ctor(arg0_type arg0, arg1_type arg1, const Args &... args)                                                                             \
+    {                                                                                                                                      \
+        typedef fmt::internal::ArgArray<sizeof...(Args)> ArgArray;                                                                         \
+        typename ArgArray::Type array{ArgArray::template make<fmt::BasicFormatter<Char>>(args)...};                                        \
+        func(arg0, arg1, fmt::ArgList(fmt::internal::make_type(args...), array));                                                          \
+    }
+
+#else
+
+#define FMT_MAKE_REF(n) fmt::internal::MakeValue<fmt::BasicFormatter<Char>>(v##n)
+#define FMT_MAKE_REF2(n) v##n
+
+// Defines a wrapper for a function taking one argument of type arg_type
+// and n additional arguments of arbitrary types.
+#define FMT_WRAP1(func, arg_type, n)                                                                                                       \
+    template<FMT_GEN(n, FMT_MAKE_TEMPLATE_ARG)>                                                                                            \
+    inline void func(arg_type arg1, FMT_GEN(n, FMT_MAKE_ARG))                                                                              \
+    {                                                                                                                                      \
+        const fmt::internal::ArgArray<n>::Type array = {FMT_GEN(n, FMT_MAKE_REF)};                                                         \
+        func(arg1, fmt::ArgList(fmt::internal::make_type(FMT_GEN(n, FMT_MAKE_REF2)), array));                                              \
+    }
+
+// Emulates a variadic function returning void on a pre-C++11 compiler.
+#define FMT_VARIADIC_VOID(func, arg_type)                                                                                                  \
+    inline void func(arg_type arg)                                                                                                         \
+    {                                                                                                                                      \
+        func(arg, fmt::ArgList());                                                                                                         \
+    }                                                                                                                                      \
+    FMT_WRAP1(func, arg_type, 1)                                                                                                           \
+    FMT_WRAP1(func, arg_type, 2)                                                                                                           \
+    FMT_WRAP1(func, arg_type, 3)                                                                                                           \
+    FMT_WRAP1(func, arg_type, 4)                                                                                                           \
+    FMT_WRAP1(func, arg_type, 5)                                                                                                           \
+    FMT_WRAP1(func, arg_type, 6)                                                                                                           \
+    FMT_WRAP1(func, arg_type, 7) FMT_WRAP1(func, arg_type, 8) FMT_WRAP1(func, arg_type, 9) FMT_WRAP1(func, arg_type, 10)
+
+#define FMT_CTOR(ctor, func, arg0_type, arg1_type, n)                                                                                      \
+    template<FMT_GEN(n, FMT_MAKE_TEMPLATE_ARG)>                                                                                            \
+    ctor(arg0_type arg0, arg1_type arg1, FMT_GEN(n, FMT_MAKE_ARG))                                                                         \
+    {                                                                                                                                      \
+        const fmt::internal::ArgArray<n>::Type array = {FMT_GEN(n, FMT_MAKE_REF)};                                                         \
+        func(arg0, arg1, fmt::ArgList(fmt::internal::make_type(FMT_GEN(n, FMT_MAKE_REF2)), array));                                        \
+    }
+
+// Emulates a variadic constructor on a pre-C++11 compiler.
+#define FMT_VARIADIC_CTOR(ctor, func, arg0_type, arg1_type)                                                                                \
+    FMT_CTOR(ctor, func, arg0_type, arg1_type, 1)                                                                                          \
+    FMT_CTOR(ctor, func, arg0_type, arg1_type, 2)                                                                                          \
+    FMT_CTOR(ctor, func, arg0_type, arg1_type, 3)                                                                                          \
+    FMT_CTOR(ctor, func, arg0_type, arg1_type, 4)                                                                                          \
+    FMT_CTOR(ctor, func, arg0_type, arg1_type, 5)                                                                                          \
+    FMT_CTOR(ctor, func, arg0_type, arg1_type, 6)                                                                                          \
+    FMT_CTOR(ctor, func, arg0_type, arg1_type, 7)                                                                                          \
+    FMT_CTOR(ctor, func, arg0_type, arg1_type, 8)                                                                                          \
+    FMT_CTOR(ctor, func, arg0_type, arg1_type, 9)                                                                                          \
+    FMT_CTOR(ctor, func, arg0_type, arg1_type, 10)
+#endif
+
+// Generates a comma-separated list with results of applying f to pairs
+// (argument, index).
+#define FMT_FOR_EACH1(f, x0) f(x0, 0)
+#define FMT_FOR_EACH2(f, x0, x1) FMT_FOR_EACH1(f, x0), f(x1, 1)
+#define FMT_FOR_EACH3(f, x0, x1, x2) FMT_FOR_EACH2(f, x0, x1), f(x2, 2)
+#define FMT_FOR_EACH4(f, x0, x1, x2, x3) FMT_FOR_EACH3(f, x0, x1, x2), f(x3, 3)
+#define FMT_FOR_EACH5(f, x0, x1, x2, x3, x4) FMT_FOR_EACH4(f, x0, x1, x2, x3), f(x4, 4)
+#define FMT_FOR_EACH6(f, x0, x1, x2, x3, x4, x5) FMT_FOR_EACH5(f, x0, x1, x2, x3, x4), f(x5, 5)
+#define FMT_FOR_EACH7(f, x0, x1, x2, x3, x4, x5, x6) FMT_FOR_EACH6(f, x0, x1, x2, x3, x4, x5), f(x6, 6)
+#define FMT_FOR_EACH8(f, x0, x1, x2, x3, x4, x5, x6, x7) FMT_FOR_EACH7(f, x0, x1, x2, x3, x4, x5, x6), f(x7, 7)
+#define FMT_FOR_EACH9(f, x0, x1, x2, x3, x4, x5, x6, x7, x8) FMT_FOR_EACH8(f, x0, x1, x2, x3, x4, x5, x6, x7), f(x8, 8)
+#define FMT_FOR_EACH10(f, x0, x1, x2, x3, x4, x5, x6, x7, x8, x9) FMT_FOR_EACH9(f, x0, x1, x2, x3, x4, x5, x6, x7, x8), f(x9, 9)
+
+/**
+ An error returned by an operating system or a language runtime,
+ for example a file opening error.
+*/
+class SystemError : public internal::RuntimeError
+{
+private:
+    FMT_API void init(int err_code, CStringRef format_str, ArgList args);
+
+protected:
+    int error_code_;
+
+    typedef char Char; // For FMT_VARIADIC_CTOR.
+
+    SystemError() {}
+
+public:
+    /**
+     \rst
+     Constructs a :class:`fmt::SystemError` object with a description
+     formatted with `fmt::format_system_error`. *message* and additional
+     arguments passed into the constructor are formatted similarly to
+     `fmt::format`.
+
+     **Example**::
+
+       // This throws a SystemError with the description
+       //   cannot open file 'madeup': No such file or directory
+       // or similar (system message may vary).
+       const char *filename = "madeup";
+       std::FILE *file = std::fopen(filename, "r");
+       if (!file)
+         throw fmt::SystemError(errno, "cannot open file '{}'", filename);
+     \endrst
+    */
+    SystemError(int error_code, CStringRef message)
+    {
+        init(error_code, message, ArgList());
+    }
+    FMT_DEFAULTED_COPY_CTOR(SystemError)
+    FMT_VARIADIC_CTOR(SystemError, init, int, CStringRef)
+
+    FMT_API ~SystemError() FMT_DTOR_NOEXCEPT FMT_OVERRIDE;
+
+    int error_code() const
+    {
+        return error_code_;
+    }
+};
+
+/**
+  \rst
+  Formats an error returned by an operating system or a language runtime,
+  for example a file opening error, and writes it to *out* in the following
+  form:
+
+  .. parsed-literal::
+     *<message>*: *<system-message>*
+
+  where *<message>* is the passed message and *<system-message>* is
+  the system message corresponding to the error code.
+  *error_code* is a system error code as given by ``errno``.
+  If *error_code* is not a valid error code such as -1, the system message
+  may look like "Unknown error -1" and is platform-dependent.
+  \endrst
+ */
+FMT_API void format_system_error(fmt::Writer &out, int error_code, fmt::StringRef message) FMT_NOEXCEPT;
+
+/**
+  \rst
+  This template provides operations for formatting and writing data into
+  a character stream. The output is stored in a buffer provided by a subclass
+  such as :class:`fmt::BasicMemoryWriter`.
+
+  You can use one of the following typedefs for common character types:
+
+  +---------+----------------------+
+  | Type    | Definition           |
+  +=========+======================+
+  | Writer  | BasicWriter<char>    |
+  +---------+----------------------+
+  | WWriter | BasicWriter<wchar_t> |
+  +---------+----------------------+
+
+  \endrst
+ */
+template<typename Char>
+class BasicWriter
+{
+private:
+    // Output buffer.
+    Buffer<Char> &buffer_;
+
+    FMT_DISALLOW_COPY_AND_ASSIGN(BasicWriter);
+
+    typedef typename internal::CharTraits<Char>::CharPtr CharPtr;
+
+#if FMT_SECURE_SCL
+    // Returns pointer value.
+    static Char *get(CharPtr p)
+    {
+        return p.base();
+    }
+#else
+    static Char *get(Char *p)
+    {
+        return p;
+    }
+#endif
+
+    // Fills the padding around the content and returns the pointer to the
+    // content area.
+    static CharPtr fill_padding(CharPtr buffer, unsigned total_size, std::size_t content_size, wchar_t fill);
+
+    // Grows the buffer by n characters and returns a pointer to the newly
+    // allocated area.
+    CharPtr grow_buffer(std::size_t n)
+    {
+        std::size_t size = buffer_.size();
+        buffer_.resize(size + n);
+        return internal::make_ptr(&buffer_[size], n);
+    }
+
+    // Writes an unsigned decimal integer.
+    template<typename UInt>
+    Char *write_unsigned_decimal(UInt value, unsigned prefix_size = 0)
+    {
+        unsigned num_digits = internal::count_digits(value);
+        Char *ptr = get(grow_buffer(prefix_size + num_digits));
+        internal::format_decimal(ptr + prefix_size, value, num_digits);
+        return ptr;
+    }
+
+    // Writes a decimal integer.
+    template<typename Int>
+    void write_decimal(Int value)
+    {
+        typedef typename internal::IntTraits<Int>::MainType MainType;
+        MainType abs_value = static_cast<MainType>(value);
+        if (internal::is_negative(value))
+        {
+            abs_value = 0 - abs_value;
+            *write_unsigned_decimal(abs_value, 1) = '-';
+        }
+        else
+        {
+            write_unsigned_decimal(abs_value, 0);
+        }
+    }
+
+    // Prepare a buffer for integer formatting.
+    CharPtr prepare_int_buffer(unsigned num_digits, const EmptySpec &, const char *prefix, unsigned prefix_size)
+    {
+        unsigned size = prefix_size + num_digits;
+        CharPtr p = grow_buffer(size);
+        std::uninitialized_copy(prefix, prefix + prefix_size, p);
+        return p + size - 1;
+    }
+
+    template<typename Spec>
+    CharPtr prepare_int_buffer(unsigned num_digits, const Spec &spec, const char *prefix, unsigned prefix_size);
+
+    // Formats an integer.
+    template<typename T, typename Spec>
+    void write_int(T value, Spec spec);
+
+    // Formats a floating-point number (double or long double).
+    template<typename T, typename Spec>
+    void write_double(T value, const Spec &spec);
+
+    // Writes a formatted string.
+    template<typename StrChar>
+    CharPtr write_str(const StrChar *s, std::size_t size, const AlignSpec &spec);
+
+    template<typename StrChar, typename Spec>
+    void write_str(const internal::Arg::StringValue<StrChar> &str, const Spec &spec);
+
+    // This following methods are private to disallow writing wide characters
+    // and strings to a char stream. If you want to print a wide string as a
+    // pointer as std::ostream does, cast it to const void*.
+    // Do not implement!
+    void operator<<(typename internal::WCharHelper<wchar_t, Char>::Unsupported);
+    void operator<<(typename internal::WCharHelper<const wchar_t *, Char>::Unsupported);
+
+    // Appends floating-point length specifier to the format string.
+    // The second argument is only used for overload resolution.
+    void append_float_length(Char *&format_ptr, long double)
+    {
+        *format_ptr++ = 'L';
+    }
+
+    template<typename T>
+    void append_float_length(Char *&, T)
+    {
+    }
+
+    template<typename Impl, typename Char_, typename Spec_>
+    friend class internal::ArgFormatterBase;
+
+    template<typename Impl, typename Char_, typename Spec_>
+    friend class BasicPrintfArgFormatter;
+
+protected:
+    /**
+      Constructs a ``BasicWriter`` object.
+     */
+    explicit BasicWriter(Buffer<Char> &b)
+        : buffer_(b)
+    {
+    }
+
+public:
+    /**
+      \rst
+      Destroys a ``BasicWriter`` object.
+      \endrst
+     */
+    virtual ~BasicWriter() {}
+
+    /**
+      Returns the total number of characters written.
+     */
+    std::size_t size() const
+    {
+        return buffer_.size();
+    }
+
+    /**
+      Returns a pointer to the output buffer content. No terminating null
+      character is appended.
+     */
+    const Char *data() const FMT_NOEXCEPT
+    {
+        return &buffer_[0];
+    }
+
+    /**
+      Returns a pointer to the output buffer content with terminating null
+      character appended.
+     */
+    const Char *c_str() const
+    {
+        std::size_t size = buffer_.size();
+        buffer_.reserve(size + 1);
+        buffer_[size] = '\0';
+        return &buffer_[0];
+    }
+
+    /**
+      \rst
+      Returns the content of the output buffer as an `std::string`.
+      \endrst
+     */
+    std::basic_string<Char> str() const
+    {
+        return std::basic_string<Char>(&buffer_[0], buffer_.size());
+    }
+
+    /**
+      \rst
+      Writes formatted data.
+
+      *args* is an argument list representing arbitrary arguments.
+
+      **Example**::
+
+         MemoryWriter out;
+         out.write("Current point:\n");
+         out.write("({:+f}, {:+f})", -3.14, 3.14);
+
+      This will write the following output to the ``out`` object:
+
+      .. code-block:: none
+
+         Current point:
+         (-3.140000, +3.140000)
+
+      The output can be accessed using :func:`data()`, :func:`c_str` or
+      :func:`str` methods.
+
+      See also :ref:`syntax`.
+      \endrst
+     */
+    void write(BasicCStringRef<Char> format, ArgList args)
+    {
+        BasicFormatter<Char>(args, *this).format(format);
+    }
+    FMT_VARIADIC_VOID(write, BasicCStringRef<Char>)
+
+    BasicWriter &operator<<(int value)
+    {
+        write_decimal(value);
+        return *this;
+    }
+    BasicWriter &operator<<(unsigned value)
+    {
+        return *this << IntFormatSpec<unsigned>(value);
+    }
+    BasicWriter &operator<<(long value)
+    {
+        write_decimal(value);
+        return *this;
+    }
+    BasicWriter &operator<<(unsigned long value)
+    {
+        return *this << IntFormatSpec<unsigned long>(value);
+    }
+    BasicWriter &operator<<(LongLong value)
+    {
+        write_decimal(value);
+        return *this;
+    }
+
+    /**
+      \rst
+      Formats *value* and writes it to the stream.
+      \endrst
+     */
+    BasicWriter &operator<<(ULongLong value)
+    {
+        return *this << IntFormatSpec<ULongLong>(value);
+    }
+
+    BasicWriter &operator<<(double value)
+    {
+        write_double(value, FormatSpec());
+        return *this;
+    }
+
+    /**
+      \rst
+      Formats *value* using the general format for floating-point numbers
+      (``'g'``) and writes it to the stream.
+      \endrst
+     */
+    BasicWriter &operator<<(long double value)
+    {
+        write_double(value, FormatSpec());
+        return *this;
+    }
+
+    /**
+      Writes a character to the stream.
+     */
+    BasicWriter &operator<<(char value)
+    {
+        buffer_.push_back(value);
+        return *this;
+    }
+
+    BasicWriter &operator<<(typename internal::WCharHelper<wchar_t, Char>::Supported value)
+    {
+        buffer_.push_back(value);
+        return *this;
+    }
+
+    /**
+      \rst
+      Writes *value* to the stream.
+      \endrst
+     */
+    BasicWriter &operator<<(fmt::BasicStringRef<Char> value)
+    {
+        const Char *str = value.data();
+        buffer_.append(str, str + value.size());
+        return *this;
+    }
+
+    BasicWriter &operator<<(typename internal::WCharHelper<StringRef, Char>::Supported value)
+    {
+        const char *str = value.data();
+        buffer_.append(str, str + value.size());
+        return *this;
+    }
+
+    template<typename T, typename Spec, typename FillChar>
+    BasicWriter &operator<<(IntFormatSpec<T, Spec, FillChar> spec)
+    {
+        internal::CharTraits<Char>::convert(FillChar());
+        write_int(spec.value(), spec);
+        return *this;
+    }
+
+    template<typename StrChar>
+    BasicWriter &operator<<(const StrFormatSpec<StrChar> &spec)
+    {
+        const StrChar *s = spec.str();
+        write_str(s, std::char_traits<Char>::length(s), spec);
+        return *this;
+    }
+
+    void clear() FMT_NOEXCEPT
+    {
+        buffer_.clear();
+    }
+
+    Buffer<Char> &buffer() FMT_NOEXCEPT
+    {
+        return buffer_;
+    }
+};
+
+template<typename Char>
+template<typename StrChar>
+typename BasicWriter<Char>::CharPtr BasicWriter<Char>::write_str(const StrChar *s, std::size_t size, const AlignSpec &spec)
+{
+    CharPtr out = CharPtr();
+    if (spec.width() > size)
+    {
+        out = grow_buffer(spec.width());
+        Char fill = internal::CharTraits<Char>::cast(spec.fill());
+        if (spec.align() == ALIGN_RIGHT)
+        {
+            std::uninitialized_fill_n(out, spec.width() - size, fill);
+            out += spec.width() - size;
+        }
+        else if (spec.align() == ALIGN_CENTER)
+        {
+            out = fill_padding(out, spec.width(), size, fill);
+        }
+        else
+        {
+            std::uninitialized_fill_n(out + size, spec.width() - size, fill);
+        }
+    }
+    else
+    {
+        out = grow_buffer(size);
+    }
+    std::uninitialized_copy(s, s + size, out);
+    return out;
+}
+
+template<typename Char>
+template<typename StrChar, typename Spec>
+void BasicWriter<Char>::write_str(const internal::Arg::StringValue<StrChar> &s, const Spec &spec)
+{
+    // Check if StrChar is convertible to Char.
+    internal::CharTraits<Char>::convert(StrChar());
+    if (spec.type_ && spec.type_ != 's')
+        internal::report_unknown_type(spec.type_, "string");
+    const StrChar *str_value = s.value;
+    std::size_t str_size = s.size;
+    if (str_size == 0)
+    {
+        if (!str_value)
+        {
+            FMT_THROW(FormatError("string pointer is null"));
+        }
+    }
+    std::size_t precision = static_cast<std::size_t>(spec.precision_);
+    if (spec.precision_ >= 0 && precision < str_size)
+        str_size = precision;
+    write_str(str_value, str_size, spec);
+}
+
+template<typename Char>
+typename BasicWriter<Char>::CharPtr BasicWriter<Char>::fill_padding(
+    CharPtr buffer, unsigned total_size, std::size_t content_size, wchar_t fill)
+{
+    std::size_t padding = total_size - content_size;
+    std::size_t left_padding = padding / 2;
+    Char fill_char = internal::CharTraits<Char>::cast(fill);
+    std::uninitialized_fill_n(buffer, left_padding, fill_char);
+    buffer += left_padding;
+    CharPtr content = buffer;
+    std::uninitialized_fill_n(buffer + content_size, padding - left_padding, fill_char);
+    return content;
+}
+
+template<typename Char>
+template<typename Spec>
+typename BasicWriter<Char>::CharPtr BasicWriter<Char>::prepare_int_buffer(
+    unsigned num_digits, const Spec &spec, const char *prefix, unsigned prefix_size)
+{
+    unsigned width = spec.width();
+    Alignment align = spec.align();
+    Char fill = internal::CharTraits<Char>::cast(spec.fill());
+    if (spec.precision() > static_cast<int>(num_digits))
+    {
+        // Octal prefix '0' is counted as a digit, so ignore it if precision
+        // is specified.
+        if (prefix_size > 0 && prefix[prefix_size - 1] == '0')
+            --prefix_size;
+        unsigned number_size = prefix_size + internal::to_unsigned(spec.precision());
+        AlignSpec subspec(number_size, '0', ALIGN_NUMERIC);
+        if (number_size >= width)
+            return prepare_int_buffer(num_digits, subspec, prefix, prefix_size);
+        buffer_.reserve(width);
+        unsigned fill_size = width - number_size;
+        if (align != ALIGN_LEFT)
+        {
+            CharPtr p = grow_buffer(fill_size);
+            std::uninitialized_fill(p, p + fill_size, fill);
+        }
+        CharPtr result = prepare_int_buffer(num_digits, subspec, prefix, prefix_size);
+        if (align == ALIGN_LEFT)
+        {
+            CharPtr p = grow_buffer(fill_size);
+            std::uninitialized_fill(p, p + fill_size, fill);
+        }
+        return result;
+    }
+    unsigned size = prefix_size + num_digits;
+    if (width <= size)
+    {
+        CharPtr p = grow_buffer(size);
+        std::uninitialized_copy(prefix, prefix + prefix_size, p);
+        return p + size - 1;
+    }
+    CharPtr p = grow_buffer(width);
+    CharPtr end = p + width;
+    if (align == ALIGN_LEFT)
+    {
+        std::uninitialized_copy(prefix, prefix + prefix_size, p);
+        p += size;
+        std::uninitialized_fill(p, end, fill);
+    }
+    else if (align == ALIGN_CENTER)
+    {
+        p = fill_padding(p, width, size, fill);
+        std::uninitialized_copy(prefix, prefix + prefix_size, p);
+        p += size;
+    }
+    else
+    {
+        if (align == ALIGN_NUMERIC)
+        {
+            if (prefix_size != 0)
+            {
+                p = std::uninitialized_copy(prefix, prefix + prefix_size, p);
+                size -= prefix_size;
+            }
+        }
+        else
+        {
+            std::uninitialized_copy(prefix, prefix + prefix_size, end - size);
+        }
+        std::uninitialized_fill(p, end - size, fill);
+        p = end;
+    }
+    return p - 1;
+}
+
+template<typename Char>
+template<typename T, typename Spec>
+void BasicWriter<Char>::write_int(T value, Spec spec)
+{
+    unsigned prefix_size = 0;
+    typedef typename internal::IntTraits<T>::MainType UnsignedType;
+    UnsignedType abs_value = static_cast<UnsignedType>(value);
+    char prefix[4] = "";
+    if (internal::is_negative(value))
+    {
+        prefix[0] = '-';
+        ++prefix_size;
+        abs_value = 0 - abs_value;
+    }
+    else if (spec.flag(SIGN_FLAG))
+    {
+        prefix[0] = spec.flag(PLUS_FLAG) ? '+' : ' ';
+        ++prefix_size;
+    }
+    switch (spec.type())
+    {
+    case 0:
+    case 'd':
+    {
+        unsigned num_digits = internal::count_digits(abs_value);
+        CharPtr p = prepare_int_buffer(num_digits, spec, prefix, prefix_size) + 1;
+        internal::format_decimal(get(p), abs_value, 0);
+        break;
+    }
+    case 'x':
+    case 'X':
+    {
+        UnsignedType n = abs_value;
+        if (spec.flag(HASH_FLAG))
+        {
+            prefix[prefix_size++] = '0';
+            prefix[prefix_size++] = spec.type_prefix();
+        }
+        unsigned num_digits = 0;
+        do
+        {
+            ++num_digits;
+        } while ((n >>= 4) != 0);
+        Char *p = get(prepare_int_buffer(num_digits, spec, prefix, prefix_size));
+        n = abs_value;
+        const char *digits = spec.type() == 'x' ? "0123456789abcdef" : "0123456789ABCDEF";
+        do
+        {
+            *p-- = digits[n & 0xf];
+        } while ((n >>= 4) != 0);
+        break;
+    }
+    case 'b':
+    case 'B':
+    {
+        UnsignedType n = abs_value;
+        if (spec.flag(HASH_FLAG))
+        {
+            prefix[prefix_size++] = '0';
+            prefix[prefix_size++] = spec.type_prefix();
+        }
+        unsigned num_digits = 0;
+        do
+        {
+            ++num_digits;
+        } while ((n >>= 1) != 0);
+        Char *p = get(prepare_int_buffer(num_digits, spec, prefix, prefix_size));
+        n = abs_value;
+        do
+        {
+            *p-- = static_cast<Char>('0' + (n & 1));
+        } while ((n >>= 1) != 0);
+        break;
+    }
+    case 'o':
+    {
+        UnsignedType n = abs_value;
+        if (spec.flag(HASH_FLAG))
+            prefix[prefix_size++] = '0';
+        unsigned num_digits = 0;
+        do
+        {
+            ++num_digits;
+        } while ((n >>= 3) != 0);
+        Char *p = get(prepare_int_buffer(num_digits, spec, prefix, prefix_size));
+        n = abs_value;
+        do
+        {
+            *p-- = static_cast<Char>('0' + (n & 7));
+        } while ((n >>= 3) != 0);
+        break;
+    }
+    case 'n':
+    {
+        unsigned num_digits = internal::count_digits(abs_value);
+        fmt::StringRef sep = "";
+#if !(defined(ANDROID) || defined(__ANDROID__))
+        sep = internal::thousands_sep(std::localeconv());
+#endif
+        unsigned size = static_cast<unsigned>(num_digits + sep.size() * ((num_digits - 1) / 3));
+        CharPtr p = prepare_int_buffer(size, spec, prefix, prefix_size) + 1;
+        internal::format_decimal(get(p), abs_value, 0, internal::ThousandsSep(sep));
+        break;
+    }
+    default:
+        internal::report_unknown_type(spec.type(), spec.flag(CHAR_FLAG) ? "char" : "integer");
+        break;
+    }
+}
+
+template<typename Char>
+template<typename T, typename Spec>
+void BasicWriter<Char>::write_double(T value, const Spec &spec)
+{
+    // Check type.
+    char type = spec.type();
+    bool upper = false;
+    switch (type)
+    {
+    case 0:
+        type = 'g';
+        break;
+    case 'e':
+    case 'f':
+    case 'g':
+    case 'a':
+        break;
+    case 'F':
+#if FMT_MSC_VER
+        // MSVC's printf doesn't support 'F'.
+        type = 'f';
+#endif
+    // Fall through.
+    case 'E':
+    case 'G':
+    case 'A':
+        upper = true;
+        break;
+    default:
+        internal::report_unknown_type(type, "double");
+        break;
+    }
+
+    char sign = 0;
+    // Use isnegative instead of value < 0 because the latter is always
+    // false for NaN.
+    if (internal::FPUtil::isnegative(static_cast<double>(value)))
+    {
+        sign = '-';
+        value = -value;
+    }
+    else if (spec.flag(SIGN_FLAG))
+    {
+        sign = spec.flag(PLUS_FLAG) ? '+' : ' ';
+    }
+
+    if (internal::FPUtil::isnotanumber(value))
+    {
+        // Format NaN ourselves because sprintf's output is not consistent
+        // across platforms.
+        std::size_t nan_size = 4;
+        const char *nan = upper ? " NAN" : " nan";
+        if (!sign)
+        {
+            --nan_size;
+            ++nan;
+        }
+        CharPtr out = write_str(nan, nan_size, spec);
+        if (sign)
+            *out = sign;
+        return;
+    }
+
+    if (internal::FPUtil::isinfinity(value))
+    {
+        // Format infinity ourselves because sprintf's output is not consistent
+        // across platforms.
+        std::size_t inf_size = 4;
+        const char *inf = upper ? " INF" : " inf";
+        if (!sign)
+        {
+            --inf_size;
+            ++inf;
+        }
+        CharPtr out = write_str(inf, inf_size, spec);
+        if (sign)
+            *out = sign;
+        return;
+    }
+
+    std::size_t offset = buffer_.size();
+    unsigned width = spec.width();
+    if (sign)
+    {
+        buffer_.reserve(buffer_.size() + (width > 1u ? width : 1u));
+        if (width > 0)
+            --width;
+        ++offset;
+    }
+
+    // Build format string.
+    enum
+    {
+        MAX_FORMAT_SIZE = 10
+    }; // longest format: %#-*.*Lg
+    Char format[MAX_FORMAT_SIZE];
+    Char *format_ptr = format;
+    *format_ptr++ = '%';
+    unsigned width_for_sprintf = width;
+    if (spec.flag(HASH_FLAG))
+        *format_ptr++ = '#';
+    if (spec.align() == ALIGN_CENTER)
+    {
+        width_for_sprintf = 0;
+    }
+    else
+    {
+        if (spec.align() == ALIGN_LEFT)
+            *format_ptr++ = '-';
+        if (width != 0)
+            *format_ptr++ = '*';
+    }
+    if (spec.precision() >= 0)
+    {
+        *format_ptr++ = '.';
+        *format_ptr++ = '*';
+    }
+
+    append_float_length(format_ptr, value);
+    *format_ptr++ = type;
+    *format_ptr = '\0';
+
+    // Format using snprintf.
+    Char fill = internal::CharTraits<Char>::cast(spec.fill());
+    unsigned n = 0;
+    Char *start = FMT_NULL;
+    for (;;)
+    {
+        std::size_t buffer_size = buffer_.capacity() - offset;
+#if FMT_MSC_VER
+        // MSVC's vsnprintf_s doesn't work with zero size, so reserve
+        // space for at least one extra character to make the size non-zero.
+        // Note that the buffer's capacity will increase by more than 1.
+        if (buffer_size == 0)
+        {
+            buffer_.reserve(offset + 1);
+            buffer_size = buffer_.capacity() - offset;
+        }
+#endif
+        start = &buffer_[offset];
+        int result = internal::CharTraits<Char>::format_float(start, buffer_size, format, width_for_sprintf, spec.precision(), value);
+        if (result >= 0)
+        {
+            n = internal::to_unsigned(result);
+            if (offset + n < buffer_.capacity())
+                break; // The buffer is large enough - continue with formatting.
+            buffer_.reserve(offset + n + 1);
+        }
+        else
+        {
+            // If result is negative we ask to increase the capacity by at least 1,
+            // but as std::vector, the buffer grows exponentially.
+            buffer_.reserve(buffer_.capacity() + 1);
+        }
+    }
+    if (sign)
+    {
+        if ((spec.align() != ALIGN_RIGHT && spec.align() != ALIGN_DEFAULT) || *start != ' ')
+        {
+            *(start - 1) = sign;
+            sign = 0;
+        }
+        else
+        {
+            *(start - 1) = fill;
+        }
+        ++n;
+    }
+    if (spec.align() == ALIGN_CENTER && spec.width() > n)
+    {
+        width = spec.width();
+        CharPtr p = grow_buffer(width);
+        std::memmove(get(p) + (width - n) / 2, get(p), n * sizeof(Char));
+        fill_padding(p, spec.width(), n, fill);
+        return;
+    }
+    if (spec.fill() != ' ' || sign)
+    {
+        while (*start == ' ')
+            *start++ = fill;
+        if (sign)
+            *(start - 1) = sign;
+    }
+    grow_buffer(n);
+}
+
+/**
+  \rst
+  This class template provides operations for formatting and writing data
+  into a character stream. The output is stored in a memory buffer that grows
+  dynamically.
+
+  You can use one of the following typedefs for common character types
+  and the standard allocator:
+
+  +---------------+-----------------------------------------------------+
+  | Type          | Definition                                          |
+  +===============+=====================================================+
+  | MemoryWriter  | BasicMemoryWriter<char, std::allocator<char>>       |
+  +---------------+-----------------------------------------------------+
+  | WMemoryWriter | BasicMemoryWriter<wchar_t, std::allocator<wchar_t>> |
+  +---------------+-----------------------------------------------------+
+
+  **Example**::
+
+     MemoryWriter out;
+     out << "The answer is " << 42 << "\n";
+     out.write("({:+f}, {:+f})", -3.14, 3.14);
+
+  This will write the following output to the ``out`` object:
+
+  .. code-block:: none
+
+     The answer is 42
+     (-3.140000, +3.140000)
+
+  The output can be converted to an ``std::string`` with ``out.str()`` or
+  accessed as a C string with ``out.c_str()``.
+  \endrst
+ */
+template<typename Char, typename Allocator = std::allocator<Char>>
+class BasicMemoryWriter : public BasicWriter<Char>
+{
+private:
+    internal::MemoryBuffer<Char, internal::INLINE_BUFFER_SIZE, Allocator> buffer_;
+
+public:
+    explicit BasicMemoryWriter(const Allocator &alloc = Allocator())
+        : BasicWriter<Char>(buffer_)
+        , buffer_(alloc)
+    {
+    }
+
+#if FMT_USE_RVALUE_REFERENCES
+    /**
+      \rst
+      Constructs a :class:`fmt::BasicMemoryWriter` object moving the content
+      of the other object to it.
+      \endrst
+     */
+    BasicMemoryWriter(BasicMemoryWriter &&other)
+        : BasicWriter<Char>(buffer_)
+        , buffer_(std::move(other.buffer_))
+    {
+    }
+
+    /**
+      \rst
+      Moves the content of the other ``BasicMemoryWriter`` object to this one.
+      \endrst
+     */
+    BasicMemoryWriter &operator=(BasicMemoryWriter &&other)
+    {
+        buffer_ = std::move(other.buffer_);
+        return *this;
+    }
+#endif
+};
+
+typedef BasicMemoryWriter<char> MemoryWriter;
+typedef BasicMemoryWriter<wchar_t> WMemoryWriter;
+
+/**
+  \rst
+  This class template provides operations for formatting and writing data
+  into a fixed-size array. For writing into a dynamically growing buffer
+  use :class:`fmt::BasicMemoryWriter`.
+
+  Any write method will throw ``std::runtime_error`` if the output doesn't fit
+  into the array.
+
+  You can use one of the following typedefs for common character types:
+
+  +--------------+---------------------------+
+  | Type         | Definition                |
+  +==============+===========================+
+  | ArrayWriter  | BasicArrayWriter<char>    |
+  +--------------+---------------------------+
+  | WArrayWriter | BasicArrayWriter<wchar_t> |
+  +--------------+---------------------------+
+  \endrst
+ */
+template<typename Char>
+class BasicArrayWriter : public BasicWriter<Char>
+{
+private:
+    internal::FixedBuffer<Char> buffer_;
+
+public:
+    /**
+     \rst
+     Constructs a :class:`fmt::BasicArrayWriter` object for *array* of the
+     given size.
+     \endrst
+     */
+    BasicArrayWriter(Char *array, std::size_t size)
+        : BasicWriter<Char>(buffer_)
+        , buffer_(array, size)
+    {
+    }
+
+    /**
+     \rst
+     Constructs a :class:`fmt::BasicArrayWriter` object for *array* of the
+     size known at compile time.
+     \endrst
+     */
+    template<std::size_t SIZE>
+    explicit BasicArrayWriter(Char (&array)[SIZE])
+        : BasicWriter<Char>(buffer_)
+        , buffer_(array, SIZE)
+    {
+    }
+};
+
+typedef BasicArrayWriter<char> ArrayWriter;
+typedef BasicArrayWriter<wchar_t> WArrayWriter;
+
+// Reports a system error without throwing an exception.
+// Can be used to report errors from destructors.
+FMT_API void report_system_error(int error_code, StringRef message) FMT_NOEXCEPT;
+
+#if FMT_USE_WINDOWS_H
+
+/** A Windows error. */
+class WindowsError : public SystemError
+{
+private:
+    FMT_API void init(int error_code, CStringRef format_str, ArgList args);
+
+public:
+    /**
+     \rst
+     Constructs a :class:`fmt::WindowsError` object with the description
+     of the form
+
+     .. parsed-literal::
+       *<message>*: *<system-message>*
+
+     where *<message>* is the formatted message and *<system-message>* is the
+     system message corresponding to the error code.
+     *error_code* is a Windows error code as given by ``GetLastError``.
+     If *error_code* is not a valid error code such as -1, the system message
+     will look like "error -1".
+
+     **Example**::
+
+       // This throws a WindowsError with the description
+       //   cannot open file 'madeup': The system cannot find the file specified.
+       // or similar (system message may vary).
+       const char *filename = "madeup";
+       LPOFSTRUCT of = LPOFSTRUCT();
+       HFILE file = OpenFile(filename, &of, OF_READ);
+       if (file == HFILE_ERROR) {
+         throw fmt::WindowsError(GetLastError(),
+                                 "cannot open file '{}'", filename);
+       }
+     \endrst
+    */
+    WindowsError(int error_code, CStringRef message)
+    {
+        init(error_code, message, ArgList());
+    }
+    FMT_VARIADIC_CTOR(WindowsError, init, int, CStringRef)
+};
+
+// Reports a Windows error without throwing an exception.
+// Can be used to report errors from destructors.
+FMT_API void report_windows_error(int error_code, StringRef message) FMT_NOEXCEPT;
+
+#endif
+
+enum Color
+{
+    BLACK,
+    RED,
+    GREEN,
+    YELLOW,
+    BLUE,
+    MAGENTA,
+    CYAN,
+    WHITE
+};
+
+/**
+  Formats a string and prints it to stdout using ANSI escape sequences
+  to specify color (experimental).
+  Example:
+    print_colored(fmt::RED, "Elapsed time: {0:.2f} seconds", 1.23);
+ */
+FMT_API void print_colored(Color c, CStringRef format, ArgList args);
+
+/**
+  \rst
+  Formats arguments and returns the result as a string.
+
+  **Example**::
+
+    std::string message = format("The answer is {}", 42);
+  \endrst
+*/
+inline std::string format(CStringRef format_str, ArgList args)
+{
+    MemoryWriter w;
+    w.write(format_str, args);
+    return w.str();
+}
+
+inline std::wstring format(WCStringRef format_str, ArgList args)
+{
+    WMemoryWriter w;
+    w.write(format_str, args);
+    return w.str();
+}
+
+/**
+  \rst
+  Prints formatted data to the file *f*.
+
+  **Example**::
+
+    print(stderr, "Don't {}!", "panic");
+  \endrst
+ */
+FMT_API void print(std::FILE *f, CStringRef format_str, ArgList args);
+
+/**
+  \rst
+  Prints formatted data to ``stdout``.
+
+  **Example**::
+
+    print("Elapsed time: {0:.2f} seconds", 1.23);
+  \endrst
+ */
+FMT_API void print(CStringRef format_str, ArgList args);
+
+/**
+  Fast integer formatter.
+ */
+class FormatInt
+{
+private:
+    // Buffer should be large enough to hold all digits (digits10 + 1),
+    // a sign and a null character.
+    enum
+    {
+        BUFFER_SIZE = std::numeric_limits<ULongLong>::digits10 + 3
+    };
+    mutable char buffer_[BUFFER_SIZE];
+    char *str_;
+
+    // Formats value in reverse and returns the number of digits.
+    char *format_decimal(ULongLong value)
+    {
+        char *buffer_end = buffer_ + BUFFER_SIZE - 1;
+        while (value >= 100)
+        {
+            // Integer division is slow so do it for a group of two digits instead
+            // of for every digit. The idea comes from the talk by Alexandrescu
+            // "Three Optimization Tips for C++". See speed-test for a comparison.
+            unsigned index = static_cast<unsigned>((value % 100) * 2);
+            value /= 100;
+            *--buffer_end = internal::Data::DIGITS[index + 1];
+            *--buffer_end = internal::Data::DIGITS[index];
+        }
+        if (value < 10)
+        {
+            *--buffer_end = static_cast<char>('0' + value);
+            return buffer_end;
+        }
+        unsigned index = static_cast<unsigned>(value * 2);
+        *--buffer_end = internal::Data::DIGITS[index + 1];
+        *--buffer_end = internal::Data::DIGITS[index];
+        return buffer_end;
+    }
+
+    void FormatSigned(LongLong value)
+    {
+        ULongLong abs_value = static_cast<ULongLong>(value);
+        bool negative = value < 0;
+        if (negative)
+            abs_value = 0 - abs_value;
+        str_ = format_decimal(abs_value);
+        if (negative)
+            *--str_ = '-';
+    }
+
+public:
+    explicit FormatInt(int value)
+    {
+        FormatSigned(value);
+    }
+    explicit FormatInt(long value)
+    {
+        FormatSigned(value);
+    }
+    explicit FormatInt(LongLong value)
+    {
+        FormatSigned(value);
+    }
+    explicit FormatInt(unsigned value)
+        : str_(format_decimal(value))
+    {
+    }
+    explicit FormatInt(unsigned long value)
+        : str_(format_decimal(value))
+    {
+    }
+    explicit FormatInt(ULongLong value)
+        : str_(format_decimal(value))
+    {
+    }
+
+    /** Returns the number of characters written to the output buffer. */
+    std::size_t size() const
+    {
+        return internal::to_unsigned(buffer_ - str_ + BUFFER_SIZE - 1);
+    }
+
+    /**
+      Returns a pointer to the output buffer content. No terminating null
+      character is appended.
+     */
+    const char *data() const
+    {
+        return str_;
+    }
+
+    /**
+      Returns a pointer to the output buffer content with terminating null
+      character appended.
+     */
+    const char *c_str() const
+    {
+        buffer_[BUFFER_SIZE - 1] = '\0';
+        return str_;
+    }
+
+    /**
+      \rst
+      Returns the content of the output buffer as an ``std::string``.
+      \endrst
+     */
+    std::string str() const
+    {
+        return std::string(str_, size());
+    }
+};
+
+// Formats a decimal integer value writing into buffer and returns
+// a pointer to the end of the formatted string. This function doesn't
+// write a terminating null character.
+template<typename T>
+inline void format_decimal(char *&buffer, T value)
+{
+    typedef typename internal::IntTraits<T>::MainType MainType;
+    MainType abs_value = static_cast<MainType>(value);
+    if (internal::is_negative(value))
+    {
+        *buffer++ = '-';
+        abs_value = 0 - abs_value;
+    }
+    if (abs_value < 100)
+    {
+        if (abs_value < 10)
+        {
+            *buffer++ = static_cast<char>('0' + abs_value);
+            return;
+        }
+        unsigned index = static_cast<unsigned>(abs_value * 2);
+        *buffer++ = internal::Data::DIGITS[index];
+        *buffer++ = internal::Data::DIGITS[index + 1];
+        return;
+    }
+    unsigned num_digits = internal::count_digits(abs_value);
+    internal::format_decimal(buffer, abs_value, num_digits);
+    buffer += num_digits;
+}
+
+/**
+  \rst
+  Returns a named argument for formatting functions.
+
+  **Example**::
+
+    print("Elapsed time: {s:.2f} seconds", arg("s", 1.23));
+
+  \endrst
+ */
+template<typename T>
+inline internal::NamedArgWithType<char, T> arg(StringRef name, const T &arg)
+{
+    return internal::NamedArgWithType<char, T>(name, arg);
+}
+
+template<typename T>
+inline internal::NamedArgWithType<wchar_t, T> arg(WStringRef name, const T &arg)
+{
+    return internal::NamedArgWithType<wchar_t, T>(name, arg);
+}
+
+// The following two functions are deleted intentionally to disable
+// nested named arguments as in ``format("{}", arg("a", arg("b", 42)))``.
+template<typename Char>
+void arg(StringRef, const internal::NamedArg<Char> &) FMT_DELETED_OR_UNDEFINED;
+template<typename Char>
+void arg(WStringRef, const internal::NamedArg<Char> &) FMT_DELETED_OR_UNDEFINED;
+} // namespace fmt
+
+#if FMT_GCC_VERSION
+// Use the system_header pragma to suppress warnings about variadic macros
+// because suppressing -Wvariadic-macros with the diagnostic pragma doesn't
+// work. It is used at the end because we want to suppress as little warnings
+// as possible.
+#pragma GCC system_header
+#endif
+
+// This is used to work around VC++ bugs in handling variadic macros.
+#define FMT_EXPAND(args) args
+
+// Returns the number of arguments.
+// Based on https://groups.google.com/forum/#!topic/comp.std.c/d-6Mj5Lko_s.
+#define FMT_NARG(...) FMT_NARG_(__VA_ARGS__, FMT_RSEQ_N())
+#define FMT_NARG_(...) FMT_EXPAND(FMT_ARG_N(__VA_ARGS__))
+#define FMT_ARG_N(_1, _2, _3, _4, _5, _6, _7, _8, _9, _10, N, ...) N
+#define FMT_RSEQ_N() 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0
+
+#define FMT_FOR_EACH_(N, f, ...) FMT_EXPAND(FMT_CONCAT(FMT_FOR_EACH, N)(f, __VA_ARGS__))
+#define FMT_FOR_EACH(f, ...) FMT_EXPAND(FMT_FOR_EACH_(FMT_NARG(__VA_ARGS__), f, __VA_ARGS__))
+
+#define FMT_ADD_ARG_NAME(type, index) type arg##index
+#define FMT_GET_ARG_NAME(type, index) arg##index
+
+#if FMT_USE_VARIADIC_TEMPLATES
+#define FMT_VARIADIC_(Const, Char, ReturnType, func, call, ...)                                                                            \
+    template<typename... Args>                                                                                                             \
+    ReturnType func(FMT_FOR_EACH(FMT_ADD_ARG_NAME, __VA_ARGS__), const Args &... args) Const                                               \
+    {                                                                                                                                      \
+        typedef fmt::internal::ArgArray<sizeof...(Args)> ArgArray;                                                                         \
+        typename ArgArray::Type array{ArgArray::template make<fmt::BasicFormatter<Char>>(args)...};                                        \
+        call(FMT_FOR_EACH(FMT_GET_ARG_NAME, __VA_ARGS__), fmt::ArgList(fmt::internal::make_type(args...), array));                         \
+    }
+#else
+// Defines a wrapper for a function taking __VA_ARGS__ arguments
+// and n additional arguments of arbitrary types.
+#define FMT_WRAP(Const, Char, ReturnType, func, call, n, ...)                                                                              \
+    template<FMT_GEN(n, FMT_MAKE_TEMPLATE_ARG)>                                                                                            \
+    inline ReturnType func(FMT_FOR_EACH(FMT_ADD_ARG_NAME, __VA_ARGS__), FMT_GEN(n, FMT_MAKE_ARG)) Const                                    \
+    {                                                                                                                                      \
+        fmt::internal::ArgArray<n>::Type arr;                                                                                              \
+        FMT_GEN(n, FMT_ASSIGN_##Char);                                                                                                     \
+        call(FMT_FOR_EACH(FMT_GET_ARG_NAME, __VA_ARGS__), fmt::ArgList(fmt::internal::make_type(FMT_GEN(n, FMT_MAKE_REF2)), arr));         \
+    }
+
+#define FMT_VARIADIC_(Const, Char, ReturnType, func, call, ...)                                                                            \
+    inline ReturnType func(FMT_FOR_EACH(FMT_ADD_ARG_NAME, __VA_ARGS__)) Const                                                              \
+    {                                                                                                                                      \
+        call(FMT_FOR_EACH(FMT_GET_ARG_NAME, __VA_ARGS__), fmt::ArgList());                                                                 \
+    }                                                                                                                                      \
+    FMT_WRAP(Const, Char, ReturnType, func, call, 1, __VA_ARGS__)                                                                          \
+    FMT_WRAP(Const, Char, ReturnType, func, call, 2, __VA_ARGS__)                                                                          \
+    FMT_WRAP(Const, Char, ReturnType, func, call, 3, __VA_ARGS__)                                                                          \
+    FMT_WRAP(Const, Char, ReturnType, func, call, 4, __VA_ARGS__)                                                                          \
+    FMT_WRAP(Const, Char, ReturnType, func, call, 5, __VA_ARGS__)                                                                          \
+    FMT_WRAP(Const, Char, ReturnType, func, call, 6, __VA_ARGS__)                                                                          \
+    FMT_WRAP(Const, Char, ReturnType, func, call, 7, __VA_ARGS__)                                                                          \
+    FMT_WRAP(Const, Char, ReturnType, func, call, 8, __VA_ARGS__)                                                                          \
+    FMT_WRAP(Const, Char, ReturnType, func, call, 9, __VA_ARGS__)                                                                          \
+    FMT_WRAP(Const, Char, ReturnType, func, call, 10, __VA_ARGS__)                                                                         \
+    FMT_WRAP(Const, Char, ReturnType, func, call, 11, __VA_ARGS__)                                                                         \
+    FMT_WRAP(Const, Char, ReturnType, func, call, 12, __VA_ARGS__)                                                                         \
+    FMT_WRAP(Const, Char, ReturnType, func, call, 13, __VA_ARGS__)                                                                         \
+    FMT_WRAP(Const, Char, ReturnType, func, call, 14, __VA_ARGS__)                                                                         \
+    FMT_WRAP(Const, Char, ReturnType, func, call, 15, __VA_ARGS__)
+#endif // FMT_USE_VARIADIC_TEMPLATES
+
+/**
+  \rst
+  Defines a variadic function with the specified return type, function name
+  and argument types passed as variable arguments to this macro.
+
+  **Example**::
+
+    void print_error(const char *file, int line, const char *format,
+                     fmt::ArgList args) {
+      fmt::print("{}: {}: ", file, line);
+      fmt::print(format, args);
+    }
+    FMT_VARIADIC(void, print_error, const char *, int, const char *)
+
+  ``FMT_VARIADIC`` is used for compatibility with legacy C++ compilers that
+  don't implement variadic templates. You don't have to use this macro if
+  you don't need legacy compiler support and can use variadic templates
+  directly::
+
+    template <typename... Args>
+    void print_error(const char *file, int line, const char *format,
+                     const Args & ... args) {
+      fmt::print("{}: {}: ", file, line);
+      fmt::print(format, args...);
+    }
+  \endrst
+ */
+#define FMT_VARIADIC(ReturnType, func, ...) FMT_VARIADIC_(, char, ReturnType, func, return func, __VA_ARGS__)
+
+#define FMT_VARIADIC_CONST(ReturnType, func, ...) FMT_VARIADIC_(const, char, ReturnType, func, return func, __VA_ARGS__)
+
+#define FMT_VARIADIC_W(ReturnType, func, ...) FMT_VARIADIC_(, wchar_t, ReturnType, func, return func, __VA_ARGS__)
+
+#define FMT_VARIADIC_CONST_W(ReturnType, func, ...) FMT_VARIADIC_(const, wchar_t, ReturnType, func, return func, __VA_ARGS__)
+
+#define FMT_CAPTURE_ARG_(id, index) ::fmt::arg(#id, id)
+
+#define FMT_CAPTURE_ARG_W_(id, index) ::fmt::arg(L## #id, id)
+
+/**
+  \rst
+  Convenient macro to capture the arguments' names and values into several
+  ``fmt::arg(name, value)``.
+
+  **Example**::
+
+    int x = 1, y = 2;
+    print("point: ({x}, {y})", FMT_CAPTURE(x, y));
+    // same as:
+    // print("point: ({x}, {y})", arg("x", x), arg("y", y));
+
+  \endrst
+ */
+#define FMT_CAPTURE(...) FMT_FOR_EACH(FMT_CAPTURE_ARG_, __VA_ARGS__)
+
+#define FMT_CAPTURE_W(...) FMT_FOR_EACH(FMT_CAPTURE_ARG_W_, __VA_ARGS__)
+
+namespace fmt {
+FMT_VARIADIC(std::string, format, CStringRef)
+FMT_VARIADIC_W(std::wstring, format, WCStringRef)
+FMT_VARIADIC(void, print, CStringRef)
+FMT_VARIADIC(void, print, std::FILE *, CStringRef)
+FMT_VARIADIC(void, print_colored, Color, CStringRef)
+
+namespace internal {
+template<typename Char>
+inline bool is_name_start(Char c)
+{
+    return ('a' <= c && c <= 'z') || ('A' <= c && c <= 'Z') || '_' == c;
+}
+
+// Parses an unsigned integer advancing s to the end of the parsed input.
+// This function assumes that the first character of s is a digit.
+template<typename Char>
+unsigned parse_nonnegative_int(const Char *&s)
+{
+    assert('0' <= *s && *s <= '9');
+    unsigned value = 0;
+    // Convert to unsigned to prevent a warning.
+    unsigned max_int = (std::numeric_limits<int>::max)();
+    unsigned big = max_int / 10;
+    do
+    {
+        // Check for overflow.
+        if (value > big)
+        {
+            value = max_int + 1;
+            break;
+        }
+        value = value * 10 + (*s - '0');
+        ++s;
+    } while ('0' <= *s && *s <= '9');
+    // Convert to unsigned to prevent a warning.
+    if (value > max_int)
+        FMT_THROW(FormatError("number is too big"));
+    return value;
+}
+
+inline void require_numeric_argument(const Arg &arg, char spec)
+{
+    if (arg.type > Arg::LAST_NUMERIC_TYPE)
+    {
+        std::string message = fmt::format("format specifier '{}' requires numeric argument", spec);
+        FMT_THROW(fmt::FormatError(message));
+    }
+}
+
+template<typename Char>
+void check_sign(const Char *&s, const Arg &arg)
+{
+    char sign = static_cast<char>(*s);
+    require_numeric_argument(arg, sign);
+    if (arg.type == Arg::UINT || arg.type == Arg::ULONG_LONG)
+    {
+        FMT_THROW(FormatError(fmt::format("format specifier '{}' requires signed argument", sign)));
+    }
+    ++s;
+}
+} // namespace internal
+
+template<typename Char, typename AF>
+inline internal::Arg BasicFormatter<Char, AF>::get_arg(BasicStringRef<Char> arg_name, const char *&error)
+{
+    if (check_no_auto_index(error))
+    {
+        map_.init(args());
+        const internal::Arg *arg = map_.find(arg_name);
+        if (arg)
+            return *arg;
+        error = "argument not found";
+    }
+    return internal::Arg();
+}
+
+template<typename Char, typename AF>
+inline internal::Arg BasicFormatter<Char, AF>::parse_arg_index(const Char *&s)
+{
+    const char *error = FMT_NULL;
+    internal::Arg arg = *s < '0' || *s > '9' ? next_arg(error) : get_arg(internal::parse_nonnegative_int(s), error);
+    if (error)
+    {
+        FMT_THROW(FormatError(*s != '}' && *s != ':' ? "invalid format string" : error));
+    }
+    return arg;
+}
+
+template<typename Char, typename AF>
+inline internal::Arg BasicFormatter<Char, AF>::parse_arg_name(const Char *&s)
+{
+    assert(internal::is_name_start(*s));
+    const Char *start = s;
+    Char c;
+    do
+    {
+        c = *++s;
+    } while (internal::is_name_start(c) || ('0' <= c && c <= '9'));
+    const char *error = FMT_NULL;
+    internal::Arg arg = get_arg(BasicStringRef<Char>(start, s - start), error);
+    if (error)
+        FMT_THROW(FormatError(error));
+    return arg;
+}
+
+template<typename Char, typename ArgFormatter>
+const Char *BasicFormatter<Char, ArgFormatter>::format(const Char *&format_str, const internal::Arg &arg)
+{
+    using internal::Arg;
+    const Char *s = format_str;
+    typename ArgFormatter::SpecType spec;
+    if (*s == ':')
+    {
+        if (arg.type == Arg::CUSTOM)
+        {
+            arg.custom.format(this, arg.custom.value, &s);
+            return s;
+        }
+        ++s;
+        // Parse fill and alignment.
+        if (Char c = *s)
+        {
+            const Char *p = s + 1;
+            spec.align_ = ALIGN_DEFAULT;
+            do
+            {
+                switch (*p)
+                {
+                case '<':
+                    spec.align_ = ALIGN_LEFT;
+                    break;
+                case '>':
+                    spec.align_ = ALIGN_RIGHT;
+                    break;
+                case '=':
+                    spec.align_ = ALIGN_NUMERIC;
+                    break;
+                case '^':
+                    spec.align_ = ALIGN_CENTER;
+                    break;
+                }
+                if (spec.align_ != ALIGN_DEFAULT)
+                {
+                    if (p != s)
+                    {
+                        if (c == '}')
+                            break;
+                        if (c == '{')
+                            FMT_THROW(FormatError("invalid fill character '{'"));
+                        s += 2;
+                        spec.fill_ = c;
+                    }
+                    else
+                        ++s;
+                    if (spec.align_ == ALIGN_NUMERIC)
+                        require_numeric_argument(arg, '=');
+                    break;
+                }
+            } while (--p >= s);
+        }
+
+        // Parse sign.
+        switch (*s)
+        {
+        case '+':
+            check_sign(s, arg);
+            spec.flags_ |= SIGN_FLAG | PLUS_FLAG;
+            break;
+        case '-':
+            check_sign(s, arg);
+            spec.flags_ |= MINUS_FLAG;
+            break;
+        case ' ':
+            check_sign(s, arg);
+            spec.flags_ |= SIGN_FLAG;
+            break;
+        }
+
+        if (*s == '#')
+        {
+            require_numeric_argument(arg, '#');
+            spec.flags_ |= HASH_FLAG;
+            ++s;
+        }
+
+        // Parse zero flag.
+        if (*s == '0')
+        {
+            require_numeric_argument(arg, '0');
+            spec.align_ = ALIGN_NUMERIC;
+            spec.fill_ = '0';
+            ++s;
+        }
+
+        // Parse width.
+        if ('0' <= *s && *s <= '9')
+        {
+            spec.width_ = internal::parse_nonnegative_int(s);
+        }
+        else if (*s == '{')
+        {
+            ++s;
+            Arg width_arg = internal::is_name_start(*s) ? parse_arg_name(s) : parse_arg_index(s);
+            if (*s++ != '}')
+                FMT_THROW(FormatError("invalid format string"));
+            ULongLong value = 0;
+            switch (width_arg.type)
+            {
+            case Arg::INT:
+                if (width_arg.int_value < 0)
+                    FMT_THROW(FormatError("negative width"));
+                value = width_arg.int_value;
+                break;
+            case Arg::UINT:
+                value = width_arg.uint_value;
+                break;
+            case Arg::LONG_LONG:
+                if (width_arg.long_long_value < 0)
+                    FMT_THROW(FormatError("negative width"));
+                value = width_arg.long_long_value;
+                break;
+            case Arg::ULONG_LONG:
+                value = width_arg.ulong_long_value;
+                break;
+            default:
+                FMT_THROW(FormatError("width is not integer"));
+            }
+            unsigned max_int = (std::numeric_limits<int>::max)();
+            if (value > max_int)
+                FMT_THROW(FormatError("number is too big"));
+            spec.width_ = static_cast<int>(value);
+        }
+
+        // Parse precision.
+        if (*s == '.')
+        {
+            ++s;
+            spec.precision_ = 0;
+            if ('0' <= *s && *s <= '9')
+            {
+                spec.precision_ = internal::parse_nonnegative_int(s);
+            }
+            else if (*s == '{')
+            {
+                ++s;
+                Arg precision_arg = internal::is_name_start(*s) ? parse_arg_name(s) : parse_arg_index(s);
+                if (*s++ != '}')
+                    FMT_THROW(FormatError("invalid format string"));
+                ULongLong value = 0;
+                switch (precision_arg.type)
+                {
+                case Arg::INT:
+                    if (precision_arg.int_value < 0)
+                        FMT_THROW(FormatError("negative precision"));
+                    value = precision_arg.int_value;
+                    break;
+                case Arg::UINT:
+                    value = precision_arg.uint_value;
+                    break;
+                case Arg::LONG_LONG:
+                    if (precision_arg.long_long_value < 0)
+                        FMT_THROW(FormatError("negative precision"));
+                    value = precision_arg.long_long_value;
+                    break;
+                case Arg::ULONG_LONG:
+                    value = precision_arg.ulong_long_value;
+                    break;
+                default:
+                    FMT_THROW(FormatError("precision is not integer"));
+                }
+                unsigned max_int = (std::numeric_limits<int>::max)();
+                if (value > max_int)
+                    FMT_THROW(FormatError("number is too big"));
+                spec.precision_ = static_cast<int>(value);
+            }
+            else
+            {
+                FMT_THROW(FormatError("missing precision specifier"));
+            }
+            if (arg.type <= Arg::LAST_INTEGER_TYPE || arg.type == Arg::POINTER)
+            {
+                FMT_THROW(FormatError(
+                    fmt::format("precision not allowed in {} format specifier", arg.type == Arg::POINTER ? "pointer" : "integer")));
+            }
+        }
+
+        // Parse type.
+        if (*s != '}' && *s)
+            spec.type_ = static_cast<char>(*s++);
+    }
+
+    if (*s++ != '}')
+        FMT_THROW(FormatError("missing '}' in format string"));
+
+    // Format argument.
+    ArgFormatter(*this, spec, s - 1).visit(arg);
+    return s;
+}
+
+template<typename Char, typename AF>
+void BasicFormatter<Char, AF>::format(BasicCStringRef<Char> format_str)
+{
+    const Char *s = format_str.c_str();
+    const Char *start = s;
+    while (*s)
+    {
+        Char c = *s++;
+        if (c != '{' && c != '}')
+            continue;
+        if (*s == c)
+        {
+            write(writer_, start, s);
+            start = ++s;
+            continue;
+        }
+        if (c == '}')
+            FMT_THROW(FormatError("unmatched '}' in format string"));
+        write(writer_, start, s - 1);
+        internal::Arg arg = internal::is_name_start(*s) ? parse_arg_name(s) : parse_arg_index(s);
+        start = s = format(s, arg);
+    }
+    write(writer_, start, s);
+}
+
+template<typename Char, typename It>
+struct ArgJoin
+{
+    It first;
+    It last;
+    BasicCStringRef<Char> sep;
+
+    ArgJoin(It first, It last, const BasicCStringRef<Char> &sep)
+        : first(first)
+        , last(last)
+        , sep(sep)
+    {
+    }
+};
+
+template<typename It>
+ArgJoin<char, It> join(It first, It last, const BasicCStringRef<char> &sep)
+{
+    return ArgJoin<char, It>(first, last, sep);
+}
+
+template<typename It>
+ArgJoin<wchar_t, It> join(It first, It last, const BasicCStringRef<wchar_t> &sep)
+{
+    return ArgJoin<wchar_t, It>(first, last, sep);
+}
+
+#if FMT_HAS_GXX_CXX11
+template<typename Range>
+auto join(const Range &range, const BasicCStringRef<char> &sep) -> ArgJoin<char, decltype(std::begin(range))>
+{
+    return join(std::begin(range), std::end(range), sep);
+}
+
+template<typename Range>
+auto join(const Range &range, const BasicCStringRef<wchar_t> &sep) -> ArgJoin<wchar_t, decltype(std::begin(range))>
+{
+    return join(std::begin(range), std::end(range), sep);
+}
+#endif
+
+template<typename ArgFormatter, typename Char, typename It>
+void format_arg(fmt::BasicFormatter<Char, ArgFormatter> &f, const Char *&format_str, const ArgJoin<Char, It> &e)
+{
+    const Char *end = format_str;
+    if (*end == ':')
+        ++end;
+    while (*end && *end != '}')
+        ++end;
+    if (*end != '}')
+        FMT_THROW(FormatError("missing '}' in format string"));
+
+    It it = e.first;
+    if (it != e.last)
+    {
+        const Char *save = format_str;
+        f.format(format_str, internal::MakeArg<fmt::BasicFormatter<Char, ArgFormatter>>(*it++));
+        while (it != e.last)
+        {
+            f.writer().write(e.sep);
+            format_str = save;
+            f.format(format_str, internal::MakeArg<fmt::BasicFormatter<Char, ArgFormatter>>(*it++));
+        }
+    }
+    format_str = end + 1;
+}
+} // namespace fmt
+
+#if FMT_USE_USER_DEFINED_LITERALS
+namespace fmt {
+namespace internal {
+
+template<typename Char>
+struct UdlFormat
+{
+    const Char *str;
+
+    template<typename... Args>
+    auto operator()(Args &&... args) const -> decltype(format(str, std::forward<Args>(args)...))
+    {
+        return format(str, std::forward<Args>(args)...);
+    }
+};
+
+template<typename Char>
+struct UdlArg
+{
+    const Char *str;
+
+    template<typename T>
+    NamedArgWithType<Char, T> operator=(T &&value) const
+    {
+        return {str, std::forward<T>(value)};
+    }
+};
+
+} // namespace internal
+
+inline namespace literals {
+
+/**
+  \rst
+  C++11 literal equivalent of :func:`fmt::format`.
+
+  **Example**::
+
+    using namespace fmt::literals;
+    std::string message = "The answer is {}"_format(42);
+  \endrst
+ */
+inline internal::UdlFormat<char> operator"" _format(const char *s, std::size_t)
+{
+    return {s};
+}
+inline internal::UdlFormat<wchar_t> operator"" _format(const wchar_t *s, std::size_t)
+{
+    return {s};
+}
+
+/**
+  \rst
+  C++11 literal equivalent of :func:`fmt::arg`.
+
+  **Example**::
+
+    using namespace fmt::literals;
+    print("Elapsed time: {s:.2f} seconds", "s"_a=1.23);
+  \endrst
+ */
+inline internal::UdlArg<char> operator"" _a(const char *s, std::size_t)
+{
+    return {s};
+}
+inline internal::UdlArg<wchar_t> operator"" _a(const wchar_t *s, std::size_t)
+{
+    return {s};
+}
+
+} // namespace literals
+} // namespace fmt
+#endif // FMT_USE_USER_DEFINED_LITERALS
+
+// Restore warnings.
+#if FMT_GCC_VERSION >= 406
+#pragma GCC diagnostic pop
+#endif
+
+#if defined(__clang__) && !defined(FMT_ICC_VERSION)
+#pragma clang diagnostic pop
+#endif
+
+#ifdef FMT_HEADER_ONLY
+#define FMT_FUNC inline
+#include "format.cc"
+#else
+#define FMT_FUNC
+#endif
+
+#endif // FMT_FORMAT_H_
diff --git a/lib/spdlog/fmt/bundled/ostream.cc b/lib/spdlog/fmt/bundled/ostream.cc
new file mode 100644
index 0000000..2d443f7
--- /dev/null
+++ b/lib/spdlog/fmt/bundled/ostream.cc
@@ -0,0 +1,35 @@
+/*
+ Formatting library for C++ - std::ostream support
+
+ Copyright (c) 2012 - 2016, Victor Zverovich
+ All rights reserved.
+
+ For the license information refer to format.h.
+ */
+
+#include "ostream.h"
+
+namespace fmt {
+
+namespace internal {
+FMT_FUNC void write(std::ostream &os, Writer &w) {
+  const char *data = w.data();
+  typedef internal::MakeUnsigned<std::streamsize>::Type UnsignedStreamSize;
+  UnsignedStreamSize size = w.size();
+  UnsignedStreamSize max_size =
+      internal::to_unsigned((std::numeric_limits<std::streamsize>::max)());
+  do {
+    UnsignedStreamSize n = size <= max_size ? size : max_size;
+    os.write(data, static_cast<std::streamsize>(n));
+    data += n;
+    size -= n;
+  } while (size != 0);
+}
+}
+
+FMT_FUNC void print(std::ostream &os, CStringRef format_str, ArgList args) {
+  MemoryWriter w;
+  w.write(format_str, args);
+  internal::write(os, w);
+}
+}  // namespace fmt
diff --git a/lib/spdlog/fmt/bundled/ostream.h b/lib/spdlog/fmt/bundled/ostream.h
new file mode 100644
index 0000000..ffa75ab
--- /dev/null
+++ b/lib/spdlog/fmt/bundled/ostream.h
@@ -0,0 +1,117 @@
+/*
+ Formatting library for C++ - std::ostream support
+
+ Copyright (c) 2012 - 2016, Victor Zverovich
+ All rights reserved.
+
+ For the license information refer to format.h.
+ */
+
+#ifndef FMT_OSTREAM_H_
+#define FMT_OSTREAM_H_
+
+#include "format.h"
+#include <ostream>
+
+namespace fmt {
+
+namespace internal {
+
+template<class Char>
+class FormatBuf : public std::basic_streambuf<Char>
+{
+private:
+    typedef typename std::basic_streambuf<Char>::int_type int_type;
+    typedef typename std::basic_streambuf<Char>::traits_type traits_type;
+
+    Buffer<Char> &buffer_;
+
+public:
+    FormatBuf(Buffer<Char> &buffer)
+        : buffer_(buffer)
+    {
+    }
+
+protected:
+    // The put-area is actually always empty. This makes the implementation
+    // simpler and has the advantage that the streambuf and the buffer are always
+    // in sync and sputc never writes into uninitialized memory. The obvious
+    // disadvantage is that each call to sputc always results in a (virtual) call
+    // to overflow. There is no disadvantage here for sputn since this always
+    // results in a call to xsputn.
+
+    int_type overflow(int_type ch = traits_type::eof()) FMT_OVERRIDE
+    {
+        if (!traits_type::eq_int_type(ch, traits_type::eof()))
+            buffer_.push_back(static_cast<Char>(ch));
+        return ch;
+    }
+
+    std::streamsize xsputn(const Char *s, std::streamsize count) FMT_OVERRIDE
+    {
+        buffer_.append(s, s + count);
+        return count;
+    }
+};
+
+Yes &convert(std::ostream &);
+
+struct DummyStream : std::ostream
+{
+    DummyStream(); // Suppress a bogus warning in MSVC.
+
+    // Hide all operator<< overloads from std::ostream.
+    template<typename T>
+    typename EnableIf<sizeof(T) == 0>::type operator<<(const T &);
+};
+
+No &operator<<(std::ostream &, int);
+
+template<typename T>
+struct ConvertToIntImpl<T, true>
+{
+    // Convert to int only if T doesn't have an overloaded operator<<.
+    enum
+    {
+        value = sizeof(convert(get<DummyStream>() << get<T>())) == sizeof(No)
+    };
+};
+
+// Write the content of w to os.
+FMT_API void write(std::ostream &os, Writer &w);
+} // namespace internal
+
+// Formats a value.
+template<typename Char, typename ArgFormatter_, typename T>
+void format_arg(BasicFormatter<Char, ArgFormatter_> &f, const Char *&format_str, const T &value)
+{
+    internal::MemoryBuffer<Char, internal::INLINE_BUFFER_SIZE> buffer;
+
+    internal::FormatBuf<Char> format_buf(buffer);
+    std::basic_ostream<Char> output(&format_buf);
+    output.exceptions(std::ios_base::failbit | std::ios_base::badbit);
+    output << value;
+
+    BasicStringRef<Char> str(&buffer[0], buffer.size());
+    typedef internal::MakeArg<BasicFormatter<Char>> MakeArg;
+    format_str = f.format(format_str, MakeArg(str));
+}
+
+/**
+  \rst
+  Prints formatted data to the stream *os*.
+
+  **Example**::
+
+    print(cerr, "Don't {}!", "panic");
+  \endrst
+ */
+FMT_API void print(std::ostream &os, CStringRef format_str, ArgList args);
+FMT_VARIADIC(void, print, std::ostream &, CStringRef)
+} // namespace fmt
+
+#ifdef FMT_HEADER_ONLY
+#include "ostream.cc"
+#endif
+
+#endif // FMT_OSTREAM_H_
diff --git a/lib/spdlog/fmt/bundled/posix.cc b/lib/spdlog/fmt/bundled/posix.cc
new file mode 100644
index 0000000..356668c
--- /dev/null
+++ b/lib/spdlog/fmt/bundled/posix.cc
@@ -0,0 +1,241 @@
+/*
+ A C++ interface to POSIX functions.
+
+ Copyright (c) 2012 - 2016, Victor Zverovich
+ All rights reserved.
+
+ For the license information refer to format.h.
+ */
+
+// Disable bogus MSVC warnings.
+#ifndef _CRT_SECURE_NO_WARNINGS
+# define _CRT_SECURE_NO_WARNINGS
+#endif
+
+#include "posix.h"
+
+#include <limits.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+
+#ifndef _WIN32
+# include <unistd.h>
+#else
+# ifndef WIN32_LEAN_AND_MEAN
+#  define WIN32_LEAN_AND_MEAN
+# endif
+# include <windows.h>
+# include <io.h>
+
+# define O_CREAT _O_CREAT
+# define O_TRUNC _O_TRUNC
+
+# ifndef S_IRUSR
+#  define S_IRUSR _S_IREAD
+# endif
+
+# ifndef S_IWUSR
+#  define S_IWUSR _S_IWRITE
+# endif
+
+# ifdef __MINGW32__
+#  define _SH_DENYNO 0x40
+# endif
+
+#endif  // _WIN32
+
+#ifdef fileno
+# undef fileno
+#endif
+
+namespace {
+#ifdef _WIN32
+// Return type of read and write functions.
+typedef int RWResult;
+
+// On Windows the count argument to read and write is unsigned, so convert
+// it from size_t preventing integer overflow.
+inline unsigned convert_rwcount(std::size_t count) {
+  return count <= UINT_MAX ? static_cast<unsigned>(count) : UINT_MAX;
+}
+#else
+// Return type of read and write functions.
+typedef ssize_t RWResult;
+
+inline std::size_t convert_rwcount(std::size_t count) { return count; }
+#endif
+}
+
+fmt::BufferedFile::~BufferedFile() FMT_NOEXCEPT {
+  if (file_ && FMT_SYSTEM(fclose(file_)) != 0)
+    fmt::report_system_error(errno, "cannot close file");
+}
+
+fmt::BufferedFile::BufferedFile(
+    fmt::CStringRef filename, fmt::CStringRef mode) {
+  FMT_RETRY_VAL(file_, FMT_SYSTEM(fopen(filename.c_str(), mode.c_str())), 0);
+  if (!file_)
+    FMT_THROW(SystemError(errno, "cannot open file {}", filename));
+}
+
+void fmt::BufferedFile::close() {
+  if (!file_)
+    return;
+  int result = FMT_SYSTEM(fclose(file_));
+  file_ = FMT_NULL;
+  if (result != 0)
+    FMT_THROW(SystemError(errno, "cannot close file"));
+}
+
+// A macro used to prevent expansion of fileno on broken versions of MinGW.
+#define FMT_ARGS
+
+int fmt::BufferedFile::fileno() const {
+  int fd = FMT_POSIX_CALL(fileno FMT_ARGS(file_));
+  if (fd == -1)
+    FMT_THROW(SystemError(errno, "cannot get file descriptor"));
+  return fd;
+}
+
+fmt::File::File(fmt::CStringRef path, int oflag) {
+  int mode = S_IRUSR | S_IWUSR;
+#if defined(_WIN32) && !defined(__MINGW32__)
+  fd_ = -1;
+  FMT_POSIX_CALL(sopen_s(&fd_, path.c_str(), oflag, _SH_DENYNO, mode));
+#else
+  FMT_RETRY(fd_, FMT_POSIX_CALL(open(path.c_str(), oflag, mode)));
+#endif
+  if (fd_ == -1)
+    FMT_THROW(SystemError(errno, "cannot open file {}", path));
+}
+
+fmt::File::~File() FMT_NOEXCEPT {
+  // Don't retry close in case of EINTR!
+  // See http://linux.derkeiler.com/Mailing-Lists/Kernel/2005-09/3000.html
+  if (fd_ != -1 && FMT_POSIX_CALL(close(fd_)) != 0)
+    fmt::report_system_error(errno, "cannot close file");
+}
+
+void fmt::File::close() {
+  if (fd_ == -1)
+    return;
+  // Don't retry close in case of EINTR!
+  // See http://linux.derkeiler.com/Mailing-Lists/Kernel/2005-09/3000.html
+  int result = FMT_POSIX_CALL(close(fd_));
+  fd_ = -1;
+  if (result != 0)
+    FMT_THROW(SystemError(errno, "cannot close file"));
+}
+
+fmt::LongLong fmt::File::size() const {
+#ifdef _WIN32
+  // Use GetFileSize instead of GetFileSizeEx for the case when _WIN32_WINNT
+  // is less than 0x0500 as is the case with some default MinGW builds.
+  // Both functions support large file sizes.
+  DWORD size_upper = 0;
+  HANDLE handle = reinterpret_cast<HANDLE>(_get_osfhandle(fd_));
+  DWORD size_lower = FMT_SYSTEM(GetFileSize(handle, &size_upper));
+  if (size_lower == INVALID_FILE_SIZE) {
+    DWORD error = GetLastError();
+    if (error != NO_ERROR)
+      FMT_THROW(WindowsError(GetLastError(), "cannot get file size"));
+  }
+  fmt::ULongLong long_size = size_upper;
+  return (long_size << sizeof(DWORD) * CHAR_BIT) | size_lower;
+#else
+  typedef struct stat Stat;
+  Stat file_stat = Stat();
+  if (FMT_POSIX_CALL(fstat(fd_, &file_stat)) == -1)
+    FMT_THROW(SystemError(errno, "cannot get file attributes"));
+  FMT_STATIC_ASSERT(sizeof(fmt::LongLong) >= sizeof(file_stat.st_size),
+      "return type of File::size is not large enough");
+  return file_stat.st_size;
+#endif
+}
+
+std::size_t fmt::File::read(void *buffer, std::size_t count) {
+  RWResult result = 0;
+  FMT_RETRY(result, FMT_POSIX_CALL(read(fd_, buffer, convert_rwcount(count))));
+  if (result < 0)
+    FMT_THROW(SystemError(errno, "cannot read from file"));
+  return internal::to_unsigned(result);
+}
+
+std::size_t fmt::File::write(const void *buffer, std::size_t count) {
+  RWResult result = 0;
+  FMT_RETRY(result, FMT_POSIX_CALL(write(fd_, buffer, convert_rwcount(count))));
+  if (result < 0)
+    FMT_THROW(SystemError(errno, "cannot write to file"));
+  return internal::to_unsigned(result);
+}
+
+fmt::File fmt::File::dup(int fd) {
+  // Don't retry as dup doesn't return EINTR.
+  // http://pubs.opengroup.org/onlinepubs/009695399/functions/dup.html
+  int new_fd = FMT_POSIX_CALL(dup(fd));
+  if (new_fd == -1)
+    FMT_THROW(SystemError(errno, "cannot duplicate file descriptor {}", fd));
+  return File(new_fd);
+}
+
+void fmt::File::dup2(int fd) {
+  int result = 0;
+  FMT_RETRY(result, FMT_POSIX_CALL(dup2(fd_, fd)));
+  if (result == -1) {
+    FMT_THROW(SystemError(errno,
+      "cannot duplicate file descriptor {} to {}", fd_, fd));
+  }
+}
+
+void fmt::File::dup2(int fd, ErrorCode &ec) FMT_NOEXCEPT {
+  int result = 0;
+  FMT_RETRY(result, FMT_POSIX_CALL(dup2(fd_, fd)));
+  if (result == -1)
+    ec = ErrorCode(errno);
+}
+
+void fmt::File::pipe(File &read_end, File &write_end) {
+  // Close the descriptors first to make sure that assignments don't throw
+  // and there are no leaks.
+  read_end.close();
+  write_end.close();
+  int fds[2] = {};
+#ifdef _WIN32
+  // Make the default pipe capacity same as on Linux 2.6.11+.
+  enum { DEFAULT_CAPACITY = 65536 };
+  int result = FMT_POSIX_CALL(pipe(fds, DEFAULT_CAPACITY, _O_BINARY));
+#else
+  // Don't retry as the pipe function doesn't return EINTR.
+  // http://pubs.opengroup.org/onlinepubs/009696799/functions/pipe.html
+  int result = FMT_POSIX_CALL(pipe(fds));
+#endif
+  if (result != 0)
+    FMT_THROW(SystemError(errno, "cannot create pipe"));
+  // The following assignments don't throw because read_fd and write_fd
+  // are closed.
+  read_end = File(fds[0]);
+  write_end = File(fds[1]);
+}
+
+fmt::BufferedFile fmt::File::fdopen(const char *mode) {
+  // Don't retry as fdopen doesn't return EINTR.
+  FILE *f = FMT_POSIX_CALL(fdopen(fd_, mode));
+  if (!f)
+    FMT_THROW(SystemError(errno, "cannot associate stream with file descriptor"));
+  BufferedFile file(f);
+  fd_ = -1;
+  return file;
+}
+
+long fmt::getpagesize() {
+#ifdef _WIN32
+  SYSTEM_INFO si;
+  GetSystemInfo(&si);
+  return si.dwPageSize;
+#else
+  long size = FMT_POSIX_CALL(sysconf(_SC_PAGESIZE));
+  if (size < 0)
+    FMT_THROW(SystemError(errno, "cannot get memory page size"));
+  return size;
+#endif
+}
diff --git a/lib/spdlog/fmt/bundled/posix.h b/lib/spdlog/fmt/bundled/posix.h
new file mode 100644
index 0000000..20af016
--- /dev/null
+++ b/lib/spdlog/fmt/bundled/posix.h
@@ -0,0 +1,423 @@
+/*
+ A C++ interface to POSIX functions.
+
+ Copyright (c) 2012 - 2016, Victor Zverovich
+ All rights reserved.
+
+ For the license information refer to format.h.
+ */
+
+#ifndef FMT_POSIX_H_
+#define FMT_POSIX_H_
+
+#if defined(__MINGW32__) || defined(__CYGWIN__)
+// Workaround MinGW bug https://sourceforge.net/p/mingw/bugs/2024/.
+#undef __STRICT_ANSI__
+#endif
+
+#include <errno.h>
+#include <fcntl.h>  // for O_RDONLY
+#include <locale.h> // for locale_t
+#include <stdio.h>
+#include <stdlib.h> // for strtod_l
+
+#include <cstddef>
+
+#if defined __APPLE__ || defined(__FreeBSD__)
+#include <xlocale.h> // for LC_NUMERIC_MASK on OS X
+#endif
+
+#include "format.h"
+
+#ifndef FMT_POSIX
+#if defined(_WIN32) && !defined(__MINGW32__)
+// Fix warnings about deprecated symbols.
+#define FMT_POSIX(call) _##call
+#else
+#define FMT_POSIX(call) call
+#endif
+#endif
+
+// Calls to system functions are wrapped in FMT_SYSTEM for testability.
+#ifdef FMT_SYSTEM
+#define FMT_POSIX_CALL(call) FMT_SYSTEM(call)
+#else
+#define FMT_SYSTEM(call) call
+#ifdef _WIN32
+// Fix warnings about deprecated symbols.
+#define FMT_POSIX_CALL(call) ::_##call
+#else
+#define FMT_POSIX_CALL(call) ::call
+#endif
+#endif
+
+// Retries the expression while it evaluates to error_result and errno
+// equals to EINTR.
+#ifndef _WIN32
+#define FMT_RETRY_VAL(result, expression, error_result)                                                                                    \
+    do                                                                                                                                     \
+    {                                                                                                                                      \
+        result = (expression);                                                                                                             \
+    } while (result == error_result && errno == EINTR)
+#else
+#define FMT_RETRY_VAL(result, expression, error_result) result = (expression)
+#endif
+
+#define FMT_RETRY(result, expression) FMT_RETRY_VAL(result, expression, -1)
+
+namespace fmt {
+
+// An error code.
+class ErrorCode
+{
+private:
+    int value_;
+
+public:
+    explicit ErrorCode(int value = 0) FMT_NOEXCEPT : value_(value) {}
+
+    int get() const FMT_NOEXCEPT
+    {
+        return value_;
+    }
+};
+
+// A buffered file.
+class BufferedFile
+{
+private:
+    FILE *file_;
+
+    friend class File;
+
+    explicit BufferedFile(FILE *f)
+        : file_(f)
+    {
+    }
+
+public:
+    // Constructs a BufferedFile object which doesn't represent any file.
+    BufferedFile() FMT_NOEXCEPT : file_(FMT_NULL) {}
+
+    // Destroys the object closing the file it represents if any.
+    FMT_API ~BufferedFile() FMT_NOEXCEPT;
+
+#if !FMT_USE_RVALUE_REFERENCES
+    // Emulate a move constructor and a move assignment operator if rvalue
+    // references are not supported.
+
+private:
+    // A proxy object to emulate a move constructor.
+    // It is private to make it impossible call operator Proxy directly.
+    struct Proxy
+    {
+        FILE *file;
+    };
+
+public:
+    // A "move constructor" for moving from a temporary.
+    BufferedFile(Proxy p) FMT_NOEXCEPT : file_(p.file) {}
+
+    // A "move constructor" for moving from an lvalue.
+    BufferedFile(BufferedFile &f) FMT_NOEXCEPT : file_(f.file_)
+    {
+        f.file_ = FMT_NULL;
+    }
+
+    // A "move assignment operator" for moving from a temporary.
+    BufferedFile &operator=(Proxy p)
+    {
+        close();
+        file_ = p.file;
+        return *this;
+    }
+
+    // A "move assignment operator" for moving from an lvalue.
+    BufferedFile &operator=(BufferedFile &other)
+    {
+        close();
+        file_ = other.file_;
+        other.file_ = FMT_NULL;
+        return *this;
+    }
+
+    // Returns a proxy object for moving from a temporary:
+    //   BufferedFile file = BufferedFile(...);
+    operator Proxy() FMT_NOEXCEPT
+    {
+        Proxy p = {file_};
+        file_ = FMT_NULL;
+        return p;
+    }
+
+#else
+private:
+    FMT_DISALLOW_COPY_AND_ASSIGN(BufferedFile);
+
+public:
+    BufferedFile(BufferedFile &&other) FMT_NOEXCEPT : file_(other.file_)
+    {
+        other.file_ = FMT_NULL;
+    }
+
+    BufferedFile &operator=(BufferedFile &&other)
+    {
+        close();
+        file_ = other.file_;
+        other.file_ = FMT_NULL;
+        return *this;
+    }
+#endif
+
+    // Opens a file.
+    FMT_API BufferedFile(CStringRef filename, CStringRef mode);
+
+    // Closes the file.
+    FMT_API void close();
+
+    // Returns the pointer to a FILE object representing this file.
+    FILE *get() const FMT_NOEXCEPT
+    {
+        return file_;
+    }
+
+    // We place parentheses around fileno to workaround a bug in some versions
+    // of MinGW that define fileno as a macro.
+    FMT_API int(fileno)() const;
+
+    void print(CStringRef format_str, const ArgList &args)
+    {
+        fmt::print(file_, format_str, args);
+    }
+    FMT_VARIADIC(void, print, CStringRef)
+};
+
+// A file. Closed file is represented by a File object with descriptor -1.
+// Methods that are not declared with FMT_NOEXCEPT may throw
+// fmt::SystemError in case of failure. Note that some errors such as
+// closing the file multiple times will cause a crash on Windows rather
+// than an exception. You can get standard behavior by overriding the
+// invalid parameter handler with _set_invalid_parameter_handler.
+class File
+{
+private:
+    int fd_; // File descriptor.
+
+    // Constructs a File object with a given descriptor.
+    explicit File(int fd)
+        : fd_(fd)
+    {
+    }
+
+public:
+    // Possible values for the oflag argument to the constructor.
+    enum
+    {
+        RDONLY = FMT_POSIX(O_RDONLY), // Open for reading only.
+        WRONLY = FMT_POSIX(O_WRONLY), // Open for writing only.
+        RDWR = FMT_POSIX(O_RDWR)      // Open for reading and writing.
+    };
+
+    // Constructs a File object which doesn't represent any file.
+    File() FMT_NOEXCEPT : fd_(-1) {}
+
+    // Opens a file and constructs a File object representing this file.
+    FMT_API File(CStringRef path, int oflag);
+
+#if !FMT_USE_RVALUE_REFERENCES
+    // Emulate a move constructor and a move assignment operator if rvalue
+    // references are not supported.
+
+private:
+    // A proxy object to emulate a move constructor.
+    // It is private to make it impossible call operator Proxy directly.
+    struct Proxy
+    {
+        int fd;
+    };
+
+public:
+    // A "move constructor" for moving from a temporary.
+    File(Proxy p) FMT_NOEXCEPT : fd_(p.fd) {}
+
+    // A "move constructor" for moving from an lvalue.
+    File(File &other) FMT_NOEXCEPT : fd_(other.fd_)
+    {
+        other.fd_ = -1;
+    }
+
+    // A "move assignment operator" for moving from a temporary.
+    File &operator=(Proxy p)
+    {
+        close();
+        fd_ = p.fd;
+        return *this;
+    }
+
+    // A "move assignment operator" for moving from an lvalue.
+    File &operator=(File &other)
+    {
+        close();
+        fd_ = other.fd_;
+        other.fd_ = -1;
+        return *this;
+    }
+
+    // Returns a proxy object for moving from a temporary:
+    //   File file = File(...);
+    operator Proxy() FMT_NOEXCEPT
+    {
+        Proxy p = {fd_};
+        fd_ = -1;
+        return p;
+    }
+
+#else
+private:
+    FMT_DISALLOW_COPY_AND_ASSIGN(File);
+
+public:
+    File(File &&other) FMT_NOEXCEPT : fd_(other.fd_)
+    {
+        other.fd_ = -1;
+    }
+
+    File &operator=(File &&other)
+    {
+        close();
+        fd_ = other.fd_;
+        other.fd_ = -1;
+        return *this;
+    }
+#endif
+
+    // Destroys the object closing the file it represents if any.
+    FMT_API ~File() FMT_NOEXCEPT;
+
+    // Returns the file descriptor.
+    int descriptor() const FMT_NOEXCEPT
+    {
+        return fd_;
+    }
+
+    // Closes the file.
+    FMT_API void close();
+
+    // Returns the file size. The size has signed type for consistency with
+    // stat::st_size.
+    FMT_API LongLong size() const;
+
+    // Attempts to read count bytes from the file into the specified buffer.
+    FMT_API std::size_t read(void *buffer, std::size_t count);
+
+    // Attempts to write count bytes from the specified buffer to the file.
+    FMT_API std::size_t write(const void *buffer, std::size_t count);
+
+    // Duplicates a file descriptor with the dup function and returns
+    // the duplicate as a file object.
+    FMT_API static File dup(int fd);
+
+    // Makes fd be the copy of this file descriptor, closing fd first if
+    // necessary.
+    FMT_API void dup2(int fd);
+
+    // Makes fd be the copy of this file descriptor, closing fd first if
+    // necessary.
+    FMT_API void dup2(int fd, ErrorCode &ec) FMT_NOEXCEPT;
+
+    // Creates a pipe setting up read_end and write_end file objects for reading
+    // and writing respectively.
+    FMT_API static void pipe(File &read_end, File &write_end);
+
+    // Creates a BufferedFile object associated with this file and detaches
+    // this File object from the file.
+    FMT_API BufferedFile fdopen(const char *mode);
+};
+
+// Returns the memory page size.
+long getpagesize();
+
+#if (defined(LC_NUMERIC_MASK) || defined(_MSC_VER)) && !defined(__ANDROID__) && !defined(__CYGWIN__)
+#define FMT_LOCALE
+#endif
+
+#ifdef FMT_LOCALE
+// A "C" numeric locale.
+class Locale
+{
+private:
+#ifdef _MSC_VER
+    typedef _locale_t locale_t;
+
+    enum
+    {
+        LC_NUMERIC_MASK = LC_NUMERIC
+    };
+
+    static locale_t newlocale(int category_mask, const char *locale, locale_t)
+    {
+        return _create_locale(category_mask, locale);
+    }
+
+    static void freelocale(locale_t locale)
+    {
+        _free_locale(locale);
+    }
+
+    static double strtod_l(const char *nptr, char **endptr, _locale_t locale)
+    {
+        return _strtod_l(nptr, endptr, locale);
+    }
+#endif
+
+    locale_t locale_;
+
+    FMT_DISALLOW_COPY_AND_ASSIGN(Locale);
+
+public:
+    typedef locale_t Type;
+
+    Locale()
+        : locale_(newlocale(LC_NUMERIC_MASK, "C", FMT_NULL))
+    {
+        if (!locale_)
+            FMT_THROW(fmt::SystemError(errno, "cannot create locale"));
+    }
+    ~Locale()
+    {
+        freelocale(locale_);
+    }
+
+    Type get() const
+    {
+        return locale_;
+    }
+
+    // Converts string to floating-point number and advances str past the end
+    // of the parsed input.
+    double strtod(const char *&str) const
+    {
+        char *end = FMT_NULL;
+        double result = strtod_l(str, &end, locale_);
+        str = end;
+        return result;
+    }
+};
+#endif // FMT_LOCALE
+} // namespace fmt
+
+#if !FMT_USE_RVALUE_REFERENCES
+namespace std {
+// For compatibility with C++98.
+inline fmt::BufferedFile &move(fmt::BufferedFile &f)
+{
+    return f;
+}
+inline fmt::File &move(fmt::File &f)
+{
+    return f;
+}
+} // namespace std
+#endif
+
+#endif // FMT_POSIX_H_
diff --git a/lib/spdlog/fmt/bundled/printf.cc b/lib/spdlog/fmt/bundled/printf.cc
new file mode 100644
index 0000000..95d7a36
--- /dev/null
+++ b/lib/spdlog/fmt/bundled/printf.cc
@@ -0,0 +1,32 @@
+/*
+ Formatting library for C++
+
+ Copyright (c) 2012 - 2016, Victor Zverovich
+ All rights reserved.
+
+ For the license information refer to format.h.
+ */
+
+#include "format.h"
+#include "printf.h"
+
+namespace fmt {
+
+template <typename Char>
+void printf(BasicWriter<Char> &w, BasicCStringRef<Char> format, ArgList args);
+
+FMT_FUNC int fprintf(std::FILE *f, CStringRef format, ArgList args) {
+  MemoryWriter w;
+  printf(w, format, args);
+  std::size_t size = w.size();
+  return std::fwrite(w.data(), 1, size, f) < size ? -1 : static_cast<int>(size);
+}
+
+#ifndef FMT_HEADER_ONLY
+
+template void PrintfFormatter<char>::format(CStringRef format);
+template void PrintfFormatter<wchar_t>::format(WCStringRef format);
+
+#endif  // FMT_HEADER_ONLY
+
+}  // namespace fmt
diff --git a/lib/spdlog/fmt/bundled/printf.h b/lib/spdlog/fmt/bundled/printf.h
new file mode 100644
index 0000000..679e8fc
--- /dev/null
+++ b/lib/spdlog/fmt/bundled/printf.h
@@ -0,0 +1,723 @@
+/*
+ Formatting library for C++
+
+ Copyright (c) 2012 - 2016, Victor Zverovich
+ All rights reserved.
+
+ For the license information refer to format.h.
+ */
+
+#ifndef FMT_PRINTF_H_
+#define FMT_PRINTF_H_
+
+#include <algorithm> // std::fill_n
+#include <limits>    // std::numeric_limits
+
+#include "ostream.h"
+
+namespace fmt {
+namespace internal {
+
+// Checks if a value fits in int - used to avoid warnings about comparing
+// signed and unsigned integers.
+template<bool IsSigned>
+struct IntChecker
+{
+    template<typename T>
+    static bool fits_in_int(T value)
+    {
+        unsigned max = std::numeric_limits<int>::max();
+        return value <= max;
+    }
+    static bool fits_in_int(bool)
+    {
+        return true;
+    }
+};
+
+template<>
+struct IntChecker<true>
+{
+    template<typename T>
+    static bool fits_in_int(T value)
+    {
+        return value >= std::numeric_limits<int>::min() && value <= std::numeric_limits<int>::max();
+    }
+    static bool fits_in_int(int)
+    {
+        return true;
+    }
+};
+
+class PrecisionHandler : public ArgVisitor<PrecisionHandler, int>
+{
+public:
+    void report_unhandled_arg()
+    {
+        FMT_THROW(FormatError("precision is not integer"));
+    }
+
+    template<typename T>
+    int visit_any_int(T value)
+    {
+        if (!IntChecker<std::numeric_limits<T>::is_signed>::fits_in_int(value))
+            FMT_THROW(FormatError("number is too big"));
+        return static_cast<int>(value);
+    }
+};
+
+// IsZeroInt::visit(arg) returns true iff arg is a zero integer.
+class IsZeroInt : public ArgVisitor<IsZeroInt, bool>
+{
+public:
+    template<typename T>
+    bool visit_any_int(T value)
+    {
+        return value == 0;
+    }
+};
+
+// returns the default type for format specific "%s"
+class DefaultType : public ArgVisitor<DefaultType, char>
+{
+public:
+    char visit_char(int)
+    {
+        return 'c';
+    }
+
+    char visit_bool(bool)
+    {
+        return 's';
+    }
+
+    char visit_pointer(const void *)
+    {
+        return 'p';
+    }
+
+    template<typename T>
+    char visit_any_int(T)
+    {
+        return 'd';
+    }
+
+    template<typename T>
+    char visit_any_double(T)
+    {
+        return 'g';
+    }
+
+    char visit_unhandled_arg()
+    {
+        return 's';
+    }
+};
+
+template<typename T, typename U>
+struct is_same
+{
+    enum
+    {
+        value = 0
+    };
+};
+
+template<typename T>
+struct is_same<T, T>
+{
+    enum
+    {
+        value = 1
+    };
+};
+
+// An argument visitor that converts an integer argument to T for printf,
+// if T is an integral type. If T is void, the argument is converted to
+// corresponding signed or unsigned type depending on the type specifier:
+// 'd' and 'i' - signed, other - unsigned)
+template<typename T = void>
+class ArgConverter : public ArgVisitor<ArgConverter<T>, void>
+{
+private:
+    internal::Arg &arg_;
+    wchar_t type_;
+
+    FMT_DISALLOW_COPY_AND_ASSIGN(ArgConverter);
+
+public:
+    ArgConverter(internal::Arg &arg, wchar_t type)
+        : arg_(arg)
+        , type_(type)
+    {
+    }
+
+    void visit_bool(bool value)
+    {
+        if (type_ != 's')
+            visit_any_int(value);
+    }
+
+    void visit_char(int value)
+    {
+        if (type_ != 's')
+            visit_any_int(value);
+    }
+
+    template<typename U>
+    void visit_any_int(U value)
+    {
+        bool is_signed = type_ == 'd' || type_ == 'i';
+        if (type_ == 's')
+        {
+            is_signed = std::numeric_limits<U>::is_signed;
+        }
+
+        using internal::Arg;
+        typedef typename internal::Conditional<is_same<T, void>::value, U, T>::type TargetType;
+        if (const_check(sizeof(TargetType) <= sizeof(int)))
+        {
+            // Extra casts are used to silence warnings.
+            if (is_signed)
+            {
+                arg_.type = Arg::INT;
+                arg_.int_value = static_cast<int>(static_cast<TargetType>(value));
+            }
+            else
+            {
+                arg_.type = Arg::UINT;
+                typedef typename internal::MakeUnsigned<TargetType>::Type Unsigned;
+                arg_.uint_value = static_cast<unsigned>(static_cast<Unsigned>(value));
+            }
+        }
+        else
+        {
+            if (is_signed)
+            {
+                arg_.type = Arg::LONG_LONG;
+                // glibc's printf doesn't sign extend arguments of smaller types:
+                //   std::printf("%lld", -42);  // prints "4294967254"
+                // but we don't have to do the same because it's a UB.
+                arg_.long_long_value = static_cast<LongLong>(value);
+            }
+            else
+            {
+                arg_.type = Arg::ULONG_LONG;
+                arg_.ulong_long_value = static_cast<typename internal::MakeUnsigned<U>::Type>(value);
+            }
+        }
+    }
+};
+
+// Converts an integer argument to char for printf.
+class CharConverter : public ArgVisitor<CharConverter, void>
+{
+private:
+    internal::Arg &arg_;
+
+    FMT_DISALLOW_COPY_AND_ASSIGN(CharConverter);
+
+public:
+    explicit CharConverter(internal::Arg &arg)
+        : arg_(arg)
+    {
+    }
+
+    template<typename T>
+    void visit_any_int(T value)
+    {
+        arg_.type = internal::Arg::CHAR;
+        arg_.int_value = static_cast<char>(value);
+    }
+};
+
+// Checks if an argument is a valid printf width specifier and sets
+// left alignment if it is negative.
+class WidthHandler : public ArgVisitor<WidthHandler, unsigned>
+{
+private:
+    FormatSpec &spec_;
+
+    FMT_DISALLOW_COPY_AND_ASSIGN(WidthHandler);
+
+public:
+    explicit WidthHandler(FormatSpec &spec)
+        : spec_(spec)
+    {
+    }
+
+    void report_unhandled_arg()
+    {
+        FMT_THROW(FormatError("width is not integer"));
+    }
+
+    template<typename T>
+    unsigned visit_any_int(T value)
+    {
+        typedef typename internal::IntTraits<T>::MainType UnsignedType;
+        UnsignedType width = static_cast<UnsignedType>(value);
+        if (internal::is_negative(value))
+        {
+            spec_.align_ = ALIGN_LEFT;
+            width = 0 - width;
+        }
+        unsigned int_max = std::numeric_limits<int>::max();
+        if (width > int_max)
+            FMT_THROW(FormatError("number is too big"));
+        return static_cast<unsigned>(width);
+    }
+};
+} // namespace internal
+
+/**
+  \rst
+  A ``printf`` argument formatter based on the `curiously recurring template
+  pattern <http://en.wikipedia.org/wiki/Curiously_recurring_template_pattern>`_.
+
+  To use `~fmt::BasicPrintfArgFormatter` define a subclass that implements some
+  or all of the visit methods with the same signatures as the methods in
+  `~fmt::ArgVisitor`, for example, `~fmt::ArgVisitor::visit_int()`.
+  Pass the subclass as the *Impl* template parameter. When a formatting
+  function processes an argument, it will dispatch to a visit method
+  specific to the argument type. For example, if the argument type is
+  ``double`` then the `~fmt::ArgVisitor::visit_double()` method of a subclass
+  will be called. If the subclass doesn't contain a method with this signature,
+  then a corresponding method of `~fmt::BasicPrintfArgFormatter` or its
+  superclass will be called.
+  \endrst
+ */
+template<typename Impl, typename Char, typename Spec>
+class BasicPrintfArgFormatter : public internal::ArgFormatterBase<Impl, Char, Spec>
+{
+private:
+    void write_null_pointer()
+    {
+        this->spec().type_ = 0;
+        this->write("(nil)");
+    }
+
+    typedef internal::ArgFormatterBase<Impl, Char, Spec> Base;
+
+public:
+    /**
+      \rst
+      Constructs an argument formatter object.
+      *writer* is a reference to the output writer and *spec* contains format
+      specifier information for standard argument types.
+      \endrst
+     */
+    BasicPrintfArgFormatter(BasicWriter<Char> &w, Spec &s)
+        : internal::ArgFormatterBase<Impl, Char, Spec>(w, s)
+    {
+    }
+
+    /** Formats an argument of type ``bool``. */
+    void visit_bool(bool value)
+    {
+        Spec &fmt_spec = this->spec();
+        if (fmt_spec.type_ != 's')
+            return this->visit_any_int(value);
+        fmt_spec.type_ = 0;
+        this->write(value);
+    }
+
+    /** Formats a character. */
+    void visit_char(int value)
+    {
+        const Spec &fmt_spec = this->spec();
+        BasicWriter<Char> &w = this->writer();
+        if (fmt_spec.type_ && fmt_spec.type_ != 'c')
+            w.write_int(value, fmt_spec);
+        typedef typename BasicWriter<Char>::CharPtr CharPtr;
+        CharPtr out = CharPtr();
+        if (fmt_spec.width_ > 1)
+        {
+            Char fill = ' ';
+            out = w.grow_buffer(fmt_spec.width_);
+            if (fmt_spec.align_ != ALIGN_LEFT)
+            {
+                std::fill_n(out, fmt_spec.width_ - 1, fill);
+                out += fmt_spec.width_ - 1;
+            }
+            else
+            {
+                std::fill_n(out + 1, fmt_spec.width_ - 1, fill);
+            }
+        }
+        else
+        {
+            out = w.grow_buffer(1);
+        }
+        *out = static_cast<Char>(value);
+    }
+
+    /** Formats a null-terminated C string. */
+    void visit_cstring(const char *value)
+    {
+        if (value)
+            Base::visit_cstring(value);
+        else if (this->spec().type_ == 'p')
+            write_null_pointer();
+        else
+            this->write("(null)");
+    }
+
+    /** Formats a pointer. */
+    void visit_pointer(const void *value)
+    {
+        if (value)
+            return Base::visit_pointer(value);
+        this->spec().type_ = 0;
+        write_null_pointer();
+    }
+
+    /** Formats an argument of a custom (user-defined) type. */
+    void visit_custom(internal::Arg::CustomValue c)
+    {
+        BasicFormatter<Char> formatter(ArgList(), this->writer());
+        const Char format_str[] = {'}', 0};
+        const Char *format = format_str;
+        c.format(&formatter, c.value, &format);
+    }
+};
+
+/** The default printf argument formatter. */
+template<typename Char>
+class PrintfArgFormatter : public BasicPrintfArgFormatter<PrintfArgFormatter<Char>, Char, FormatSpec>
+{
+public:
+    /** Constructs an argument formatter object. */
+    PrintfArgFormatter(BasicWriter<Char> &w, FormatSpec &s)
+        : BasicPrintfArgFormatter<PrintfArgFormatter<Char>, Char, FormatSpec>(w, s)
+    {
+    }
+};
+
+/** This template formats data and writes the output to a writer. */
+template<typename Char, typename ArgFormatter = PrintfArgFormatter<Char>>
+class PrintfFormatter : private internal::FormatterBase
+{
+private:
+    BasicWriter<Char> &writer_;
+
+    void parse_flags(FormatSpec &spec, const Char *&s);
+
+    // Returns the argument with specified index or, if arg_index is equal
+    // to the maximum unsigned value, the next argument.
+    internal::Arg get_arg(const Char *s, unsigned arg_index = (std::numeric_limits<unsigned>::max)());
+
+    // Parses argument index, flags and width and returns the argument index.
+    unsigned parse_header(const Char *&s, FormatSpec &spec);
+
+public:
+    /**
+     \rst
+     Constructs a ``PrintfFormatter`` object. References to the arguments and
+     the writer are stored in the formatter object so make sure they have
+     appropriate lifetimes.
+     \endrst
+     */
+    explicit PrintfFormatter(const ArgList &al, BasicWriter<Char> &w)
+        : FormatterBase(al)
+        , writer_(w)
+    {
+    }
+
+    /** Formats stored arguments and writes the output to the writer. */
+    void format(BasicCStringRef<Char> format_str);
+};
+
+template<typename Char, typename AF>
+void PrintfFormatter<Char, AF>::parse_flags(FormatSpec &spec, const Char *&s)
+{
+    for (;;)
+    {
+        switch (*s++)
+        {
+        case '-':
+            spec.align_ = ALIGN_LEFT;
+            break;
+        case '+':
+            spec.flags_ |= SIGN_FLAG | PLUS_FLAG;
+            break;
+        case '0':
+            spec.fill_ = '0';
+            break;
+        case ' ':
+            spec.flags_ |= SIGN_FLAG;
+            break;
+        case '#':
+            spec.flags_ |= HASH_FLAG;
+            break;
+        default:
+            --s;
+            return;
+        }
+    }
+}
+
+template<typename Char, typename AF>
+internal::Arg PrintfFormatter<Char, AF>::get_arg(const Char *s, unsigned arg_index)
+{
+    (void)s;
+    const char *error = FMT_NULL;
+    internal::Arg arg = arg_index == std::numeric_limits<unsigned>::max() ? next_arg(error) : FormatterBase::get_arg(arg_index - 1, error);
+    if (error)
+        FMT_THROW(FormatError(!*s ? "invalid format string" : error));
+    return arg;
+}
+
+template<typename Char, typename AF>
+unsigned PrintfFormatter<Char, AF>::parse_header(const Char *&s, FormatSpec &spec)
+{
+    unsigned arg_index = std::numeric_limits<unsigned>::max();
+    Char c = *s;
+    if (c >= '0' && c <= '9')
+    {
+        // Parse an argument index (if followed by '$') or a width possibly
+        // preceded with '0' flag(s).
+        unsigned value = internal::parse_nonnegative_int(s);
+        if (*s == '$') // value is an argument index
+        {
+            ++s;
+            arg_index = value;
+        }
+        else
+        {
+            if (c == '0')
+                spec.fill_ = '0';
+            if (value != 0)
+            {
+                // Nonzero value means that we parsed width and don't need to
+                // parse it or flags again, so return now.
+                spec.width_ = value;
+                return arg_index;
+            }
+        }
+    }
+    parse_flags(spec, s);
+    // Parse width.
+    if (*s >= '0' && *s <= '9')
+    {
+        spec.width_ = internal::parse_nonnegative_int(s);
+    }
+    else if (*s == '*')
+    {
+        ++s;
+        spec.width_ = internal::WidthHandler(spec).visit(get_arg(s));
+    }
+    return arg_index;
+}
+
+template<typename Char, typename AF>
+void PrintfFormatter<Char, AF>::format(BasicCStringRef<Char> format_str)
+{
+    const Char *start = format_str.c_str();
+    const Char *s = start;
+    while (*s)
+    {
+        Char c = *s++;
+        if (c != '%')
+            continue;
+        if (*s == c)
+        {
+            write(writer_, start, s);
+            start = ++s;
+            continue;
+        }
+        write(writer_, start, s - 1);
+
+        FormatSpec spec;
+        spec.align_ = ALIGN_RIGHT;
+
+        // Parse argument index, flags and width.
+        unsigned arg_index = parse_header(s, spec);
+
+        // Parse precision.
+        if (*s == '.')
+        {
+            ++s;
+            if ('0' <= *s && *s <= '9')
+            {
+                spec.precision_ = static_cast<int>(internal::parse_nonnegative_int(s));
+            }
+            else if (*s == '*')
+            {
+                ++s;
+                spec.precision_ = internal::PrecisionHandler().visit(get_arg(s));
+            }
+            else
+            {
+                spec.precision_ = 0;
+            }
+        }
+
+        using internal::Arg;
+        Arg arg = get_arg(s, arg_index);
+        if (spec.flag(HASH_FLAG) && internal::IsZeroInt().visit(arg))
+            spec.flags_ &= ~internal::to_unsigned<int>(HASH_FLAG);
+        if (spec.fill_ == '0')
+        {
+            if (arg.type <= Arg::LAST_NUMERIC_TYPE)
+                spec.align_ = ALIGN_NUMERIC;
+            else
+                spec.fill_ = ' '; // Ignore '0' flag for non-numeric types.
+        }
+
+        // Parse length and convert the argument to the required type.
+        using internal::ArgConverter;
+        switch (*s++)
+        {
+        case 'h':
+            if (*s == 'h')
+                ArgConverter<signed char>(arg, *++s).visit(arg);
+            else
+                ArgConverter<short>(arg, *s).visit(arg);
+            break;
+        case 'l':
+            if (*s == 'l')
+                ArgConverter<fmt::LongLong>(arg, *++s).visit(arg);
+            else
+                ArgConverter<long>(arg, *s).visit(arg);
+            break;
+        case 'j':
+            ArgConverter<intmax_t>(arg, *s).visit(arg);
+            break;
+        case 'z':
+            ArgConverter<std::size_t>(arg, *s).visit(arg);
+            break;
+        case 't':
+            ArgConverter<std::ptrdiff_t>(arg, *s).visit(arg);
+            break;
+        case 'L':
+            // printf produces garbage when 'L' is omitted for long double, no
+            // need to do the same.
+            break;
+        default:
+            --s;
+            ArgConverter<void>(arg, *s).visit(arg);
+        }
+
+        // Parse type.
+        if (!*s)
+            FMT_THROW(FormatError("invalid format string"));
+        spec.type_ = static_cast<char>(*s++);
+
+        if (spec.type_ == 's')
+        {
+            // set the format type to the default if 's' is specified
+            spec.type_ = internal::DefaultType().visit(arg);
+        }
+
+        if (arg.type <= Arg::LAST_INTEGER_TYPE)
+        {
+            // Normalize type.
+            switch (spec.type_)
+            {
+            case 'i':
+            case 'u':
+                spec.type_ = 'd';
+                break;
+            case 'c':
+                // TODO: handle wchar_t
+                internal::CharConverter(arg).visit(arg);
+                break;
+            }
+        }
+
+        start = s;
+
+        // Format argument.
+        AF(writer_, spec).visit(arg);
+    }
+    write(writer_, start, s);
+}
+
+inline void printf(Writer &w, CStringRef format, ArgList args)
+{
+    PrintfFormatter<char>(args, w).format(format);
+}
+FMT_VARIADIC(void, printf, Writer &, CStringRef)
+
+inline void printf(WWriter &w, WCStringRef format, ArgList args)
+{
+    PrintfFormatter<wchar_t>(args, w).format(format);
+}
+FMT_VARIADIC(void, printf, WWriter &, WCStringRef)
+
+/**
+  \rst
+  Formats arguments and returns the result as a string.
+
+  **Example**::
+
+    std::string message = fmt::sprintf("The answer is %d", 42);
+  \endrst
+*/
+inline std::string sprintf(CStringRef format, ArgList args)
+{
+    MemoryWriter w;
+    printf(w, format, args);
+    return w.str();
+}
+FMT_VARIADIC(std::string, sprintf, CStringRef)
+
+inline std::wstring sprintf(WCStringRef format, ArgList args)
+{
+    WMemoryWriter w;
+    printf(w, format, args);
+    return w.str();
+}
+FMT_VARIADIC_W(std::wstring, sprintf, WCStringRef)
+
+/**
+  \rst
+  Prints formatted data to the file *f*.
+
+  **Example**::
+
+    fmt::fprintf(stderr, "Don't %s!", "panic");
+  \endrst
+ */
+FMT_API int fprintf(std::FILE *f, CStringRef format, ArgList args);
+FMT_VARIADIC(int, fprintf, std::FILE *, CStringRef)
+
+/**
+  \rst
+  Prints formatted data to ``stdout``.
+
+  **Example**::
+
+    fmt::printf("Elapsed time: %.2f seconds", 1.23);
+  \endrst
+ */
+inline int printf(CStringRef format, ArgList args)
+{
+    return fprintf(stdout, format, args);
+}
+FMT_VARIADIC(int, printf, CStringRef)
+
+/**
+  \rst
+  Prints formatted data to the stream *os*.
+
+  **Example**::
+
+    fprintf(cerr, "Don't %s!", "panic");
+  \endrst
+ */
+inline int fprintf(std::ostream &os, CStringRef format_str, ArgList args)
+{
+    MemoryWriter w;
+    printf(w, format_str, args);
+    internal::write(os, w);
+    return static_cast<int>(w.size());
+}
+FMT_VARIADIC(int, fprintf, std::ostream &, CStringRef)
+} // namespace fmt
+
+#ifdef FMT_HEADER_ONLY
+#include "printf.cc"
+#endif
+
+#endif // FMT_PRINTF_H_
diff --git a/lib/spdlog/fmt/bundled/time.h b/lib/spdlog/fmt/bundled/time.h
new file mode 100644
index 0000000..1d4210c
--- /dev/null
+++ b/lib/spdlog/fmt/bundled/time.h
@@ -0,0 +1,188 @@
+/*
+ Formatting library for C++ - time formatting
+
+ Copyright (c) 2012 - 2016, Victor Zverovich
+ All rights reserved.
+
+ For the license information refer to format.h.
+ */
+
+#ifndef FMT_TIME_H_
+#define FMT_TIME_H_
+
+#include "format.h"
+#include <ctime>
+
+#ifdef _MSC_VER
+#pragma warning(push)
+#pragma warning(disable : 4702) // unreachable code
+#pragma warning(disable : 4996) // "deprecated" functions
+#endif
+
+namespace fmt {
+template<typename ArgFormatter>
+void format_arg(BasicFormatter<char, ArgFormatter> &f, const char *&format_str, const std::tm &tm)
+{
+    if (*format_str == ':')
+        ++format_str;
+    const char *end = format_str;
+    while (*end && *end != '}')
+        ++end;
+    if (*end != '}')
+        FMT_THROW(FormatError("missing '}' in format string"));
+    internal::MemoryBuffer<char, internal::INLINE_BUFFER_SIZE> format;
+    format.append(format_str, end + 1);
+    format[format.size() - 1] = '\0';
+    Buffer<char> &buffer = f.writer().buffer();
+    std::size_t start = buffer.size();
+    for (;;)
+    {
+        std::size_t size = buffer.capacity() - start;
+        std::size_t count = std::strftime(&buffer[start], size, &format[0], &tm);
+        if (count != 0)
+        {
+            buffer.resize(start + count);
+            break;
+        }
+        if (size >= format.size() * 256)
+        {
+            // If the buffer is 256 times larger than the format string, assume
+            // that `strftime` gives an empty result. There doesn't seem to be a
+            // better way to distinguish the two cases:
+            // https://github.com/fmtlib/fmt/issues/367
+            break;
+        }
+        const std::size_t MIN_GROWTH = 10;
+        buffer.reserve(buffer.capacity() + (size > MIN_GROWTH ? size : MIN_GROWTH));
+    }
+    format_str = end + 1;
+}
+
+namespace internal {
+inline Null<> localtime_r(...)
+{
+    return Null<>();
+}
+inline Null<> localtime_s(...)
+{
+    return Null<>();
+}
+inline Null<> gmtime_r(...)
+{
+    return Null<>();
+}
+inline Null<> gmtime_s(...)
+{
+    return Null<>();
+}
+} // namespace internal
+
+// Thread-safe replacement for std::localtime
+inline std::tm localtime(std::time_t time)
+{
+    struct LocalTime
+    {
+        std::time_t time_;
+        std::tm tm_;
+
+        LocalTime(std::time_t t)
+            : time_(t)
+        {
+        }
+
+        bool run()
+        {
+            using namespace fmt::internal;
+            return handle(localtime_r(&time_, &tm_));
+        }
+
+        bool handle(std::tm *tm)
+        {
+            return tm != FMT_NULL;
+        }
+
+        bool handle(internal::Null<>)
+        {
+            using namespace fmt::internal;
+            return fallback(localtime_s(&tm_, &time_));
+        }
+
+        bool fallback(int res)
+        {
+            return res == 0;
+        }
+
+        bool fallback(internal::Null<>)
+        {
+            using namespace fmt::internal;
+            std::tm *tm = std::localtime(&time_);
+            if (tm)
+                tm_ = *tm;
+            return tm != FMT_NULL;
+        }
+    };
+    LocalTime lt(time);
+    if (lt.run())
+        return lt.tm_;
+    // Too big time values may be unsupported.
+    FMT_THROW(fmt::FormatError("time_t value out of range"));
+    return std::tm();
+}
+
+// Thread-safe replacement for std::gmtime
+inline std::tm gmtime(std::time_t time)
+{
+    struct GMTime
+    {
+        std::time_t time_;
+        std::tm tm_;
+
+        GMTime(std::time_t t)
+            : time_(t)
+        {
+        }
+
+        bool run()
+        {
+            using namespace fmt::internal;
+            return handle(gmtime_r(&time_, &tm_));
+        }
+
+        bool handle(std::tm *tm)
+        {
+            return tm != FMT_NULL;
+        }
+
+        bool handle(internal::Null<>)
+        {
+            using namespace fmt::internal;
+            return fallback(gmtime_s(&tm_, &time_));
+        }
+
+        bool fallback(int res)
+        {
+            return res == 0;
+        }
+
+        bool fallback(internal::Null<>)
+        {
+            std::tm *tm = std::gmtime(&time_);
+            if (tm != FMT_NULL)
+                tm_ = *tm;
+            return tm != FMT_NULL;
+        }
+    };
+    GMTime gt(time);
+    if (gt.run())
+        return gt.tm_;
+    // Too big time values may be unsupported.
+    FMT_THROW(fmt::FormatError("time_t value out of range"));
+    return std::tm();
+}
+} // namespace fmt
+
+#ifdef _MSC_VER
+#pragma warning(pop)
+#endif
+
+#endif // FMT_TIME_H_
diff --git a/lib/spdlog/fmt/fmt.h b/lib/spdlog/fmt/fmt.h
new file mode 100644
index 0000000..e2e0485
--- /dev/null
+++ b/lib/spdlog/fmt/fmt.h
@@ -0,0 +1,33 @@
+//
+// Copyright(c) 2016 Gabi Melman.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+//
+
+#pragma once
+
+//
+// Include a bundled header-only copy of fmtlib or an external one.
+// By default spdlog include its own copy.
+//
+
+#if !defined(SPDLOG_FMT_EXTERNAL)
+
+#ifndef FMT_HEADER_ONLY
+#define FMT_HEADER_ONLY
+#endif
+#ifndef FMT_USE_WINDOWS_H
+#define FMT_USE_WINDOWS_H 0
+#endif
+#include "bundled/format.h"
+#if defined(SPDLOG_FMT_PRINTF)
+#include "bundled/printf.h"
+#endif
+
+#else // external fmtlib
+
+#include <fmt/format.h>
+#if defined(SPDLOG_FMT_PRINTF)
+#include <fmt/printf.h>
+#endif
+
+#endif
diff --git a/lib/spdlog/fmt/ostr.h b/lib/spdlog/fmt/ostr.h
new file mode 100644
index 0000000..9902898
--- /dev/null
+++ b/lib/spdlog/fmt/ostr.h
@@ -0,0 +1,18 @@
+//
+// Copyright(c) 2016 Gabi Melman.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+//
+
+#pragma once
+//
+// include bundled or external copy of fmtlib's ostream support
+//
+#if !defined(SPDLOG_FMT_EXTERNAL)
+#ifndef FMT_HEADER_ONLY
+#define FMT_HEADER_ONLY
+#endif
+#include "bundled/ostream.h"
+#include "fmt.h"
+#else
+#include <fmt/ostream.h>
+#endif
diff --git a/lib/spdlog/formatter.h b/lib/spdlog/formatter.h
new file mode 100644
index 0000000..55388ec
--- /dev/null
+++ b/lib/spdlog/formatter.h
@@ -0,0 +1,46 @@
+//
+// Copyright(c) 2015 Gabi Melman.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+//
+
+#pragma once
+
+#include "details/log_msg.h"
+
+#include <memory>
+#include <string>
+#include <vector>
+
+namespace spdlog {
+namespace details {
+class flag_formatter;
+}
+
+class formatter
+{
+public:
+    virtual ~formatter() = default;
+    virtual void format(details::log_msg &msg) = 0;
+};
+
+class pattern_formatter SPDLOG_FINAL : public formatter
+{
+public:
+    explicit pattern_formatter(const std::string &pattern, pattern_time_type pattern_time = pattern_time_type::local,
+        std::string eol = spdlog::details::os::default_eol);
+    pattern_formatter(const pattern_formatter &) = delete;
+    pattern_formatter &operator=(const pattern_formatter &) = delete;
+    void format(details::log_msg &msg) override;
+
+private:
+    const std::string _eol;
+    const std::string _pattern;
+    const pattern_time_type _pattern_time;
+    std::vector<std::unique_ptr<details::flag_formatter>> _formatters;
+    std::tm get_time(details::log_msg &msg);
+    void handle_flag(char flag);
+    void compile_pattern(const std::string &pattern);
+};
+} // namespace spdlog
+
+#include "details/pattern_formatter_impl.h"
diff --git a/lib/spdlog/logger.h b/lib/spdlog/logger.h
new file mode 100644
index 0000000..aa4a2c5
--- /dev/null
+++ b/lib/spdlog/logger.h
@@ -0,0 +1,152 @@
+//
+// Copyright(c) 2015 Gabi Melman.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+//
+
+#pragma once
+
+// Thread safe logger (except for set_pattern(..), set_formatter(..) and set_error_handler())
+// Has name, log level, vector of std::shared sink pointers and formatter
+// Upon each log write the logger:
+// 1. Checks if its log level is enough to log the message
+// 2. Format the message using the formatter function
+// 3. Pass the formatted message to its sinks to performa the actual logging
+
+#include "common.h"
+#include "sinks/base_sink.h"
+
+#include <memory>
+#include <string>
+#include <vector>
+
+namespace spdlog {
+
+class logger
+{
+public:
+    logger(const std::string &name, sink_ptr single_sink);
+    logger(const std::string &name, sinks_init_list sinks);
+
+    template<class It>
+    logger(std::string name, const It &begin, const It &end);
+
+    virtual ~logger();
+
+    logger(const logger &) = delete;
+    logger &operator=(const logger &) = delete;
+
+    template<typename... Args>
+    void log(level::level_enum lvl, const char *fmt, const Args &... args);
+
+    template<typename... Args>
+    void log(level::level_enum lvl, const char *msg);
+
+    template<typename Arg1, typename... Args>
+    void trace(const char *fmt, const Arg1 &, const Args &... args);
+
+    template<typename Arg1, typename... Args>
+    void debug(const char *fmt, const Arg1 &, const Args &... args);
+
+    template<typename Arg1, typename... Args>
+    void info(const char *fmt, const Arg1 &, const Args &... args);
+
+    template<typename Arg1, typename... Args>
+    void warn(const char *fmt, const Arg1 &, const Args &... args);
+
+    template<typename Arg1, typename... Args>
+    void error(const char *fmt, const Arg1 &, const Args &... args);
+
+    template<typename Arg1, typename... Args>
+    void critical(const char *fmt, const Arg1 &, const Args &... args);
+
+#ifdef SPDLOG_WCHAR_TO_UTF8_SUPPORT
+    template<typename... Args>
+    void log(level::level_enum lvl, const wchar_t *msg);
+
+    template<typename... Args>
+    void log(level::level_enum lvl, const wchar_t *fmt, const Args &... args);
+
+    template<typename... Args>
+    void trace(const wchar_t *fmt, const Args &... args);
+
+    template<typename... Args>
+    void debug(const wchar_t *fmt, const Args &... args);
+
+    template<typename... Args>
+    void info(const wchar_t *fmt, const Args &... args);
+
+    template<typename... Args>
+    void warn(const wchar_t *fmt, const Args &... args);
+
+    template<typename... Args>
+    void error(const wchar_t *fmt, const Args &... args);
+
+    template<typename... Args>
+    void critical(const wchar_t *fmt, const Args &... args);
+#endif // SPDLOG_WCHAR_TO_UTF8_SUPPORT
+
+    template<typename T>
+    void log(level::level_enum lvl, const T &);
+
+    template<typename T>
+    void trace(const T &msg);
+
+    template<typename T>
+    void debug(const T &msg);
+
+    template<typename T>
+    void info(const T &msg);
+
+    template<typename T>
+    void warn(const T &msg);
+
+    template<typename T>
+    void error(const T &msg);
+
+    template<typename T>
+    void critical(const T &msg);
+
+    bool should_log(level::level_enum msg_level) const;
+    void set_level(level::level_enum log_level);
+    level::level_enum level() const;
+    const std::string &name() const;
+    void set_pattern(const std::string &pattern, pattern_time_type pattern_time = pattern_time_type::local);
+    void set_formatter(formatter_ptr msg_formatter);
+
+    // automatically call flush() if message level >= log_level
+    void flush_on(level::level_enum log_level);
+
+    virtual void flush();
+
+    const std::vector<sink_ptr> &sinks() const;
+
+    // error handler
+    virtual void set_error_handler(log_err_handler err_handler);
+    virtual log_err_handler error_handler();
+
+protected:
+    virtual void _sink_it(details::log_msg &msg);
+    virtual void _set_pattern(const std::string &pattern, pattern_time_type pattern_time);
+    virtual void _set_formatter(formatter_ptr msg_formatter);
+
+    // default error handler: print the error to stderr with the max rate of 1 message/minute
+    virtual void _default_err_handler(const std::string &msg);
+
+    // return true if the given message level should trigger a flush
+    bool _should_flush_on(const details::log_msg &msg);
+
+    // increment the message count (only if defined(SPDLOG_ENABLE_MESSAGE_COUNTER))
+    void _incr_msg_counter(details::log_msg &msg);
+
+    const std::string _name;
+    std::vector<sink_ptr> _sinks;
+    formatter_ptr _formatter;
+    spdlog::level_t _level;
+    spdlog::level_t _flush_level;
+    log_err_handler _err_handler;
+    std::atomic<time_t> _last_err_time;
+    std::atomic<size_t> _msg_counter;
+};
+} // namespace spdlog
+
+#include "details/logger_impl.h"
diff --git a/lib/spdlog/sinks/android_sink.h b/lib/spdlog/sinks/android_sink.h
new file mode 100644
index 0000000..dd81163
--- /dev/null
+++ b/lib/spdlog/sinks/android_sink.h
@@ -0,0 +1,91 @@
+//
+// Copyright(c) 2015 Gabi Melman.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+//
+
+#pragma once
+
+#if defined(__ANDROID__)
+
+#include "../details/os.h"
+#include "sink.h"
+
+#include <android/log.h>
+#include <chrono>
+#include <mutex>
+#include <string>
+#include <thread>
+
+#if !defined(SPDLOG_ANDROID_RETRIES)
+#define SPDLOG_ANDROID_RETRIES 2
+#endif
+
+namespace spdlog {
+namespace sinks {
+
+/*
+ * Android sink (logging using __android_log_write)
+ * __android_log_write is thread-safe. No lock is needed.
+ */
+class android_sink : public sink
+{
+public:
+    explicit android_sink(const std::string &tag = "spdlog", bool use_raw_msg = false)
+        : _tag(tag)
+        , _use_raw_msg(use_raw_msg)
+    {
+    }
+
+    void log(const details::log_msg &msg) override
+    {
+        const android_LogPriority priority = convert_to_android(msg.level);
+        const char *msg_output = (_use_raw_msg ? msg.raw.c_str() : msg.formatted.c_str());
+
+        // See system/core/liblog/logger_write.c for explanation of return value
+        int ret = __android_log_write(priority, _tag.c_str(), msg_output);
+        int retry_count = 0;
+        while ((ret == -11 /*EAGAIN*/) && (retry_count < SPDLOG_ANDROID_RETRIES))
+        {
+            details::os::sleep_for_millis(5);
+            ret = __android_log_write(priority, _tag.c_str(), msg_output);
+            retry_count++;
+        }
+
+        if (ret < 0)
+        {
+            throw spdlog_ex("__android_log_write() failed", ret);
+        }
+    }
+
+    void flush() override {}
+
+private:
+    static android_LogPriority convert_to_android(spdlog::level::level_enum level)
+    {
+        switch (level)
+        {
+        case spdlog::level::trace:
+            return ANDROID_LOG_VERBOSE;
+        case spdlog::level::debug:
+            return ANDROID_LOG_DEBUG;
+        case spdlog::level::info:
+            return ANDROID_LOG_INFO;
+        case spdlog::level::warn:
+            return ANDROID_LOG_WARN;
+        case spdlog::level::err:
+            return ANDROID_LOG_ERROR;
+        case spdlog::level::critical:
+            return ANDROID_LOG_FATAL;
+        default:
+            return ANDROID_LOG_DEFAULT;
+        }
+    }
+
+    std::string _tag;
+    bool _use_raw_msg;
+};
+
+} // namespace sinks
+} // namespace spdlog
+
+#endif
diff --git a/lib/spdlog/sinks/ansicolor_sink.h b/lib/spdlog/sinks/ansicolor_sink.h
new file mode 100644
index 0000000..e74389c
--- /dev/null
+++ b/lib/spdlog/sinks/ansicolor_sink.h
@@ -0,0 +1,150 @@
+//
+// Copyright(c) 2017 spdlog authors.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+//
+
+#pragma once
+
+#include "../common.h"
+#include "../details/os.h"
+#include "base_sink.h"
+
+#include <string>
+#include <unordered_map>
+
+namespace spdlog {
+namespace sinks {
+
+/**
+ * This sink prefixes the output with an ANSI escape sequence color code depending on the severity
+ * of the message.
+ * If no color terminal detected, omit the escape codes.
+ */
+template<class Mutex>
+class ansicolor_sink : public base_sink<Mutex>
+{
+public:
+    explicit ansicolor_sink(FILE *file)
+        : target_file_(file)
+    {
+        should_do_colors_ = details::os::in_terminal(file) && details::os::is_color_terminal();
+        colors_[level::trace] = white;
+        colors_[level::debug] = cyan;
+        colors_[level::info] = green;
+        colors_[level::warn] = yellow + bold;
+        colors_[level::err] = red + bold;
+        colors_[level::critical] = bold + on_red;
+        colors_[level::off] = reset;
+    }
+
+    ~ansicolor_sink() override
+    {
+        _flush();
+    }
+
+    void set_color(level::level_enum color_level, const std::string &color)
+    {
+        std::lock_guard<Mutex> lock(base_sink<Mutex>::_mutex);
+        colors_[color_level] = color;
+    }
+
+    /// Formatting codes
+    const std::string reset = "\033[m";
+    const std::string bold = "\033[1m";
+    const std::string dark = "\033[2m";
+    const std::string underline = "\033[4m";
+    const std::string blink = "\033[5m";
+    const std::string reverse = "\033[7m";
+    const std::string concealed = "\033[8m";
+    const std::string clear_line = "\033[K";
+
+    // Foreground colors
+    const std::string black = "\033[30m";
+    const std::string red = "\033[31m";
+    const std::string green = "\033[32m";
+    const std::string yellow = "\033[33m";
+    const std::string blue = "\033[34m";
+    const std::string magenta = "\033[35m";
+    const std::string cyan = "\033[36m";
+    const std::string white = "\033[37m";
+
+    /// Background colors
+    const std::string on_black = "\033[40m";
+    const std::string on_red = "\033[41m";
+    const std::string on_green = "\033[42m";
+    const std::string on_yellow = "\033[43m";
+    const std::string on_blue = "\033[44m";
+    const std::string on_magenta = "\033[45m";
+    const std::string on_cyan = "\033[46m";
+    const std::string on_white = "\033[47m";
+
+protected:
+    void _sink_it(const details::log_msg &msg) override
+    {
+        // Wrap the originally formatted message in color codes.
+        // If color is not supported in the terminal, log as is instead.
+        if (should_do_colors_ && msg.color_range_end > msg.color_range_start)
+        {
+            // before color range
+            _print_range(msg, 0, msg.color_range_start);
+            // in color range
+            _print_ccode(colors_[msg.level]);
+            _print_range(msg, msg.color_range_start, msg.color_range_end);
+            _print_ccode(reset);
+            // after color range
+            _print_range(msg, msg.color_range_end, msg.formatted.size());
+        }
+        else
+        {
+            _print_range(msg, 0, msg.formatted.size());
+        }
+        _flush();
+    }
+
+    void _flush() override
+    {
+        fflush(target_file_);
+    }
+
+private:
+    void _print_ccode(const std::string &color_code)
+    {
+        fwrite(color_code.data(), sizeof(char), color_code.size(), target_file_);
+    }
+    void _print_range(const details::log_msg &msg, size_t start, size_t end)
+    {
+        fwrite(msg.formatted.data() + start, sizeof(char), end - start, target_file_);
+    }
+    FILE *target_file_;
+    bool should_do_colors_;
+    std::unordered_map<level::level_enum, std::string, level::level_hasher> colors_;
+};
+
+template<class Mutex>
+class ansicolor_stdout_sink : public ansicolor_sink<Mutex>
+{
+public:
+    ansicolor_stdout_sink()
+        : ansicolor_sink<Mutex>(stdout)
+    {
+    }
+};
+
+using ansicolor_stdout_sink_mt = ansicolor_stdout_sink<std::mutex>;
+using ansicolor_stdout_sink_st = ansicolor_stdout_sink<details::null_mutex>;
+
+template<class Mutex>
+class ansicolor_stderr_sink : public ansicolor_sink<Mutex>
+{
+public:
+    ansicolor_stderr_sink()
+        : ansicolor_sink<Mutex>(stderr)
+    {
+    }
+};
+
+using ansicolor_stderr_sink_mt = ansicolor_stderr_sink<std::mutex>;
+using ansicolor_stderr_sink_st = ansicolor_stderr_sink<details::null_mutex>;
+
+} // namespace sinks
+} // namespace spdlog
diff --git a/lib/spdlog/sinks/base_sink.h b/lib/spdlog/sinks/base_sink.h
new file mode 100644
index 0000000..96cd001
--- /dev/null
+++ b/lib/spdlog/sinks/base_sink.h
@@ -0,0 +1,49 @@
+//
+// Copyright(c) 2015 Gabi Melman.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+//
+
+#pragma once
+//
+// base sink templated over a mutex (either dummy or real)
+// concrete implementation should only override the _sink_it method.
+// all locking is taken care of here so no locking needed by the implementers..
+//
+
+#include "../common.h"
+#include "../details/log_msg.h"
+#include "../formatter.h"
+#include "sink.h"
+
+#include <mutex>
+
+namespace spdlog {
+namespace sinks {
+template<class Mutex>
+class base_sink : public sink
+{
+public:
+    base_sink() = default;
+
+    base_sink(const base_sink &) = delete;
+    base_sink &operator=(const base_sink &) = delete;
+
+    void log(const details::log_msg &msg) SPDLOG_FINAL override
+    {
+        std::lock_guard<Mutex> lock(_mutex);
+        _sink_it(msg);
+    }
+
+    void flush() SPDLOG_FINAL override
+    {
+        std::lock_guard<Mutex> lock(_mutex);
+        _flush();
+    }
+
+protected:
+    virtual void _sink_it(const details::log_msg &msg) = 0;
+    virtual void _flush() = 0;
+    Mutex _mutex;
+};
+} // namespace sinks
+} // namespace spdlog
diff --git a/lib/spdlog/sinks/dist_sink.h b/lib/spdlog/sinks/dist_sink.h
new file mode 100644
index 0000000..b4a7b6a
--- /dev/null
+++ b/lib/spdlog/sinks/dist_sink.h
@@ -0,0 +1,77 @@
+//
+// Copyright (c) 2015 David Schury, Gabi Melman
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+//
+
+#pragma once
+
+#include "../details/log_msg.h"
+#include "../details/null_mutex.h"
+#include "base_sink.h"
+#include "sink.h"
+
+#include <algorithm>
+#include <memory>
+#include <mutex>
+#include <vector>
+
+// Distribution sink (mux). Stores a vector of sinks which get called when log is called
+
+namespace spdlog {
+namespace sinks {
+template<class Mutex>
+class dist_sink : public base_sink<Mutex>
+{
+public:
+    explicit dist_sink()
+        : _sinks()
+    {
+    }
+    dist_sink(const dist_sink &) = delete;
+    dist_sink &operator=(const dist_sink &) = delete;
+
+protected:
+    std::vector<std::shared_ptr<sink>> _sinks;
+
+    void _sink_it(const details::log_msg &msg) override
+    {
+        for (auto &sink : _sinks)
+        {
+            if (sink->should_log(msg.level))
+            {
+                sink->log(msg);
+            }
+        }
+    }
+
+    void _flush() override
+    {
+        for (auto &sink : _sinks)
+            sink->flush();
+    }
+
+public:
+    void add_sink(std::shared_ptr<sink> sink)
+    {
+        std::lock_guard<Mutex> lock(base_sink<Mutex>::_mutex);
+        _sinks.push_back(sink);
+    }
+
+    void remove_sink(std::shared_ptr<sink> sink)
+    {
+        std::lock_guard<Mutex> lock(base_sink<Mutex>::_mutex);
+        _sinks.erase(std::remove(_sinks.begin(), _sinks.end(), sink), _sinks.end());
+    }
+
+    void remove_all_sinks()
+    {
+        std::lock_guard<Mutex> lock(base_sink<Mutex>::_mutex);
+        _sinks.clear();
+    }
+};
+
+using dist_sink_mt = dist_sink<std::mutex>;
+using dist_sink_st = dist_sink<details::null_mutex>;
+
+} // namespace sinks
+} // namespace spdlog
diff --git a/lib/spdlog/sinks/file_sinks.h b/lib/spdlog/sinks/file_sinks.h
new file mode 100644
index 0000000..109c493
--- /dev/null
+++ b/lib/spdlog/sinks/file_sinks.h
@@ -0,0 +1,255 @@
+//
+// Copyright(c) 2015 Gabi Melman.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+//
+
+#pragma once
+
+#include "../details/file_helper.h"
+#include "../details/null_mutex.h"
+#include "../fmt/fmt.h"
+#include "base_sink.h"
+
+#include <algorithm>
+#include <cerrno>
+#include <chrono>
+#include <cstdio>
+#include <ctime>
+#include <mutex>
+#include <string>
+
+namespace spdlog {
+namespace sinks {
+/*
+ * Trivial file sink with single file as target
+ */
+template<class Mutex>
+class simple_file_sink SPDLOG_FINAL : public base_sink<Mutex>
+{
+public:
+    explicit simple_file_sink(const filename_t &filename, bool truncate = false)
+        : _force_flush(false)
+    {
+        _file_helper.open(filename, truncate);
+    }
+
+    void set_force_flush(bool force_flush)
+    {
+        _force_flush = force_flush;
+    }
+
+protected:
+    void _sink_it(const details::log_msg &msg) override
+    {
+        _file_helper.write(msg);
+        if (_force_flush)
+        {
+            _file_helper.flush();
+        }
+    }
+
+    void _flush() override
+    {
+        _file_helper.flush();
+    }
+
+private:
+    details::file_helper _file_helper;
+    bool _force_flush;
+};
+
+using simple_file_sink_mt = simple_file_sink<std::mutex>;
+using simple_file_sink_st = simple_file_sink<details::null_mutex>;
+
+/*
+ * Rotating file sink based on size
+ */
+template<class Mutex>
+class rotating_file_sink SPDLOG_FINAL : public base_sink<Mutex>
+{
+public:
+    rotating_file_sink(filename_t base_filename, std::size_t max_size, std::size_t max_files)
+        : _base_filename(std::move(base_filename))
+        , _max_size(max_size)
+        , _max_files(max_files)
+    {
+        _file_helper.open(calc_filename(_base_filename, 0));
+        _current_size = _file_helper.size(); // expensive. called only once
+    }
+
+    // calc filename according to index and file extension if exists.
+    // e.g. calc_filename("logs/mylog.txt, 3) => "logs/mylog.3.txt".
+    static filename_t calc_filename(const filename_t &filename, std::size_t index)
+    {
+        typename std::conditional<std::is_same<filename_t::value_type, char>::value, fmt::MemoryWriter, fmt::WMemoryWriter>::type w;
+        if (index != 0u)
+        {
+            filename_t basename, ext;
+            std::tie(basename, ext) = details::file_helper::split_by_extenstion(filename);
+            w.write(SPDLOG_FILENAME_T("{}.{}{}"), basename, index, ext);
+        }
+        else
+        {
+            w.write(SPDLOG_FILENAME_T("{}"), filename);
+        }
+        return w.str();
+    }
+
+protected:
+    void _sink_it(const details::log_msg &msg) override
+    {
+        _current_size += msg.formatted.size();
+        if (_current_size > _max_size)
+        {
+            _rotate();
+            _current_size = msg.formatted.size();
+        }
+        _file_helper.write(msg);
+    }
+
+    void _flush() override
+    {
+        _file_helper.flush();
+    }
+
+private:
+    // Rotate files:
+    // log.txt -> log.1.txt
+    // log.1.txt -> log.2.txt
+    // log.2.txt -> log.3.txt
+    // log.3.txt -> delete
+    void _rotate()
+    {
+        using details::os::filename_to_str;
+        _file_helper.close();
+        for (auto i = _max_files; i > 0; --i)
+        {
+            filename_t src = calc_filename(_base_filename, i - 1);
+            filename_t target = calc_filename(_base_filename, i);
+
+            if (details::file_helper::file_exists(target))
+            {
+                if (details::os::remove(target) != 0)
+                {
+                    throw spdlog_ex("rotating_file_sink: failed removing " + filename_to_str(target), errno);
+                }
+            }
+            if (details::file_helper::file_exists(src) && details::os::rename(src, target) != 0)
+            {
+                throw spdlog_ex("rotating_file_sink: failed renaming " + filename_to_str(src) + " to " + filename_to_str(target), errno);
+            }
+        }
+        _file_helper.reopen(true);
+    }
+
+    filename_t _base_filename;
+    std::size_t _max_size;
+    std::size_t _max_files;
+    std::size_t _current_size;
+    details::file_helper _file_helper;
+};
+
+using rotating_file_sink_mt = rotating_file_sink<std::mutex>;
+using rotating_file_sink_st = rotating_file_sink<details::null_mutex>;
+
+/*
+ * Default generator of daily log file names.
+ */
+struct default_daily_file_name_calculator
+{
+    // Create filename for the form filename.YYYY-MM-DD_hh-mm.ext
+    static filename_t calc_filename(const filename_t &filename)
+    {
+        std::tm tm = spdlog::details::os::localtime();
+        filename_t basename, ext;
+        std::tie(basename, ext) = details::file_helper::split_by_extenstion(filename);
+        std::conditional<std::is_same<filename_t::value_type, char>::value, fmt::MemoryWriter, fmt::WMemoryWriter>::type w;
+        w.write(SPDLOG_FILENAME_T("{}_{:04d}-{:02d}-{:02d}_{:02d}-{:02d}{}"), basename, tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday,
+            tm.tm_hour, tm.tm_min, ext);
+        return w.str();
+    }
+};
+
+/*
+ * Generator of daily log file names in format basename.YYYY-MM-DD.ext
+ */
+struct dateonly_daily_file_name_calculator
+{
+    // Create filename for the form basename.YYYY-MM-DD
+    static filename_t calc_filename(const filename_t &filename)
+    {
+        std::tm tm = spdlog::details::os::localtime();
+        filename_t basename, ext;
+        std::tie(basename, ext) = details::file_helper::split_by_extenstion(filename);
+        std::conditional<std::is_same<filename_t::value_type, char>::value, fmt::MemoryWriter, fmt::WMemoryWriter>::type w;
+        w.write(SPDLOG_FILENAME_T("{}_{:04d}-{:02d}-{:02d}{}"), basename, tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday, ext);
+        return w.str();
+    }
+};
+
+/*
+ * Rotating file sink based on date. rotates at midnight
+ */
+template<class Mutex, class FileNameCalc = default_daily_file_name_calculator>
+class daily_file_sink SPDLOG_FINAL : public base_sink<Mutex>
+{
+public:
+    // create daily file sink which rotates on given time
+    daily_file_sink(filename_t base_filename, int rotation_hour, int rotation_minute)
+        : _base_filename(std::move(base_filename))
+        , _rotation_h(rotation_hour)
+        , _rotation_m(rotation_minute)
+    {
+        if (rotation_hour < 0 || rotation_hour > 23 || rotation_minute < 0 || rotation_minute > 59)
+        {
+            throw spdlog_ex("daily_file_sink: Invalid rotation time in ctor");
+        }
+        _rotation_tp = _next_rotation_tp();
+        _file_helper.open(FileNameCalc::calc_filename(_base_filename));
+    }
+
+protected:
+    void _sink_it(const details::log_msg &msg) override
+    {
+        if (std::chrono::system_clock::now() >= _rotation_tp)
+        {
+            _file_helper.open(FileNameCalc::calc_filename(_base_filename));
+            _rotation_tp = _next_rotation_tp();
+        }
+        _file_helper.write(msg);
+    }
+
+    void _flush() override
+    {
+        _file_helper.flush();
+    }
+
+private:
+    std::chrono::system_clock::time_point _next_rotation_tp()
+    {
+        auto now = std::chrono::system_clock::now();
+        time_t tnow = std::chrono::system_clock::to_time_t(now);
+        tm date = spdlog::details::os::localtime(tnow);
+        date.tm_hour = _rotation_h;
+        date.tm_min = _rotation_m;
+        date.tm_sec = 0;
+        auto rotation_time = std::chrono::system_clock::from_time_t(std::mktime(&date));
+        if (rotation_time > now)
+        {
+            return rotation_time;
+        }
+        return {rotation_time + std::chrono::hours(24)};
+    }
+
+    filename_t _base_filename;
+    int _rotation_h;
+    int _rotation_m;
+    std::chrono::system_clock::time_point _rotation_tp;
+    details::file_helper _file_helper;
+};
+
+using daily_file_sink_mt = daily_file_sink<std::mutex>;
+using daily_file_sink_st = daily_file_sink<details::null_mutex>;
+
+} // namespace sinks
+} // namespace spdlog
diff --git a/lib/spdlog/sinks/msvc_sink.h b/lib/spdlog/sinks/msvc_sink.h
new file mode 100644
index 0000000..09a5d67
--- /dev/null
+++ b/lib/spdlog/sinks/msvc_sink.h
@@ -0,0 +1,44 @@
+//
+// Copyright(c) 2016 Alexander Dalshov.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+//
+
+#pragma once
+
+#if defined(_WIN32)
+
+#include "../details/null_mutex.h"
+#include "base_sink.h"
+
+#include <winbase.h>
+
+#include <mutex>
+#include <string>
+
+namespace spdlog {
+namespace sinks {
+/*
+ * MSVC sink (logging using OutputDebugStringA)
+ */
+template<class Mutex>
+class msvc_sink : public base_sink<Mutex>
+{
+public:
+    explicit msvc_sink() {}
+
+protected:
+    void _sink_it(const details::log_msg &msg) override
+    {
+        OutputDebugStringA(msg.formatted.c_str());
+    }
+
+    void _flush() override {}
+};
+
+using msvc_sink_mt = msvc_sink<std::mutex>;
+using msvc_sink_st = msvc_sink<details::null_mutex>;
+
+} // namespace sinks
+} // namespace spdlog
+
+#endif
diff --git a/lib/spdlog/sinks/null_sink.h b/lib/spdlog/sinks/null_sink.h
new file mode 100644
index 0000000..c254bc5
--- /dev/null
+++ b/lib/spdlog/sinks/null_sink.h
@@ -0,0 +1,29 @@
+//
+// Copyright(c) 2015 Gabi Melman.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+//
+
+#pragma once
+
+#include "../details/null_mutex.h"
+#include "base_sink.h"
+
+#include <mutex>
+
+namespace spdlog {
+namespace sinks {
+
+template<class Mutex>
+class null_sink : public base_sink<Mutex>
+{
+protected:
+    void _sink_it(const details::log_msg &) override {}
+
+    void _flush() override {}
+};
+
+using null_sink_mt = null_sink<details::null_mutex>;
+using null_sink_st = null_sink<details::null_mutex>;
+
+} // namespace sinks
+} // namespace spdlog
diff --git a/lib/spdlog/sinks/ostream_sink.h b/lib/spdlog/sinks/ostream_sink.h
new file mode 100644
index 0000000..9728138
--- /dev/null
+++ b/lib/spdlog/sinks/ostream_sink.h
@@ -0,0 +1,49 @@
+//
+// Copyright(c) 2015 Gabi Melman.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+//
+
+#pragma once
+
+#include "../details/null_mutex.h"
+#include "base_sink.h"
+
+#include <mutex>
+#include <ostream>
+
+namespace spdlog {
+namespace sinks {
+template<class Mutex>
+class ostream_sink : public base_sink<Mutex>
+{
+public:
+    explicit ostream_sink(std::ostream &os, bool force_flush = false)
+        : _ostream(os)
+        , _force_flush(force_flush)
+    {
+    }
+    ostream_sink(const ostream_sink &) = delete;
+    ostream_sink &operator=(const ostream_sink &) = delete;
+
+protected:
+    void _sink_it(const details::log_msg &msg) override
+    {
+        _ostream.write(msg.formatted.data(), msg.formatted.size());
+        if (_force_flush)
+            _ostream.flush();
+    }
+
+    void _flush() override
+    {
+        _ostream.flush();
+    }
+
+    std::ostream &_ostream;
+    bool _force_flush;
+};
+
+using ostream_sink_mt = ostream_sink<std::mutex>;
+using ostream_sink_st = ostream_sink<details::null_mutex>;
+
+} // namespace sinks
+} // namespace spdlog
diff --git a/lib/spdlog/sinks/sink.h b/lib/spdlog/sinks/sink.h
new file mode 100644
index 0000000..b4e3806
--- /dev/null
+++ b/lib/spdlog/sinks/sink.h
@@ -0,0 +1,44 @@
+//
+// Copyright(c) 2015 Gabi Melman.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+//
+
+#pragma once
+
+#include "../details/log_msg.h"
+
+namespace spdlog {
+namespace sinks {
+class sink
+{
+public:
+    virtual ~sink() = default;
+
+    virtual void log(const details::log_msg &msg) = 0;
+    virtual void flush() = 0;
+
+    bool should_log(level::level_enum msg_level) const;
+    void set_level(level::level_enum log_level);
+    level::level_enum level() const;
+
+private:
+    level_t _level{level::trace};
+};
+
+inline bool sink::should_log(level::level_enum msg_level) const
+{
+    return msg_level >= _level.load(std::memory_order_relaxed);
+}
+
+inline void sink::set_level(level::level_enum log_level)
+{
+    _level.store(log_level);
+}
+
+inline level::level_enum sink::level() const
+{
+    return static_cast<spdlog::level::level_enum>(_level.load(std::memory_order_relaxed));
+}
+
+} // namespace sinks
+} // namespace spdlog
diff --git a/lib/spdlog/sinks/stdout_sinks.h b/lib/spdlog/sinks/stdout_sinks.h
new file mode 100644
index 0000000..b15d080
--- /dev/null
+++ b/lib/spdlog/sinks/stdout_sinks.h
@@ -0,0 +1,79 @@
+//
+// Copyright(c) 2015 Gabi Melman.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+//
+
+#pragma once
+
+#include "../details/null_mutex.h"
+#include "base_sink.h"
+
+#include <cstdio>
+#include <memory>
+#include <mutex>
+
+namespace spdlog {
+namespace sinks {
+
+template<class Mutex>
+class stdout_sink SPDLOG_FINAL : public base_sink<Mutex>
+{
+    using MyType = stdout_sink<Mutex>;
+
+public:
+    explicit stdout_sink() = default;
+
+    static std::shared_ptr<MyType> instance()
+    {
+        static std::shared_ptr<MyType> instance = std::make_shared<MyType>();
+        return instance;
+    }
+
+protected:
+    void _sink_it(const details::log_msg &msg) override
+    {
+        fwrite(msg.formatted.data(), sizeof(char), msg.formatted.size(), stdout);
+        _flush();
+    }
+
+    void _flush() override
+    {
+        fflush(stdout);
+    }
+};
+
+using stdout_sink_mt = stdout_sink<std::mutex>;
+using stdout_sink_st = stdout_sink<details::null_mutex>;
+
+template<class Mutex>
+class stderr_sink SPDLOG_FINAL : public base_sink<Mutex>
+{
+    using MyType = stderr_sink<Mutex>;
+
+public:
+    explicit stderr_sink() = default;
+
+    static std::shared_ptr<MyType> instance()
+    {
+        static std::shared_ptr<MyType> instance = std::make_shared<MyType>();
+        return instance;
+    }
+
+protected:
+    void _sink_it(const details::log_msg &msg) override
+    {
+        fwrite(msg.formatted.data(), sizeof(char), msg.formatted.size(), stderr);
+        _flush();
+    }
+
+    void _flush() override
+    {
+        fflush(stderr);
+    }
+};
+
+using stderr_sink_mt = stderr_sink<std::mutex>;
+using stderr_sink_st = stderr_sink<details::null_mutex>;
+
+} // namespace sinks
+} // namespace spdlog
diff --git a/lib/spdlog/sinks/syslog_sink.h b/lib/spdlog/sinks/syslog_sink.h
new file mode 100644
index 0000000..17bbb1d
--- /dev/null
+++ b/lib/spdlog/sinks/syslog_sink.h
@@ -0,0 +1,76 @@
+//
+// Copyright(c) 2015 Gabi Melman.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+//
+
+#pragma once
+
+#include "../common.h"
+
+#ifdef SPDLOG_ENABLE_SYSLOG
+
+#include "../details/log_msg.h"
+#include "sink.h"
+
+#include <array>
+#include <string>
+#include <syslog.h>
+
+namespace spdlog {
+namespace sinks {
+/**
+ * Sink that write to syslog using the `syscall()` library call.
+ *
+ * Locking is not needed, as `syslog()` itself is thread-safe.
+ */
+class syslog_sink : public sink
+{
+public:
+    //
+    syslog_sink(const std::string &ident = "", int syslog_option = 0, int syslog_facility = LOG_USER)
+        : _ident(ident)
+    {
+        _priorities[static_cast<size_t>(level::trace)] = LOG_DEBUG;
+        _priorities[static_cast<size_t>(level::debug)] = LOG_DEBUG;
+        _priorities[static_cast<size_t>(level::info)] = LOG_INFO;
+        _priorities[static_cast<size_t>(level::warn)] = LOG_WARNING;
+        _priorities[static_cast<size_t>(level::err)] = LOG_ERR;
+        _priorities[static_cast<size_t>(level::critical)] = LOG_CRIT;
+        _priorities[static_cast<size_t>(level::off)] = LOG_INFO;
+
+        // set ident to be program name if empty
+        ::openlog(_ident.empty() ? nullptr : _ident.c_str(), syslog_option, syslog_facility);
+    }
+
+    ~syslog_sink() override
+    {
+        ::closelog();
+    }
+
+    syslog_sink(const syslog_sink &) = delete;
+    syslog_sink &operator=(const syslog_sink &) = delete;
+
+    void log(const details::log_msg &msg) override
+    {
+        ::syslog(syslog_prio_from_level(msg), "%s", msg.raw.str().c_str());
+    }
+
+    void flush() override {}
+
+private:
+    std::array<int, 7> _priorities;
+    // must store the ident because the man says openlog might use the pointer as is and not a string copy
+    const std::string _ident;
+
+    //
+    // Simply maps spdlog's log level to syslog priority level.
+    //
+    int syslog_prio_from_level(const details::log_msg &msg) const
+    {
+        return _priorities[static_cast<size_t>(msg.level)];
+    }
+};
+} // namespace sinks
+} // namespace spdlog
+
+#endif
diff --git a/lib/spdlog/sinks/wincolor_sink.h b/lib/spdlog/sinks/wincolor_sink.h
new file mode 100644
index 0000000..402fa12
--- /dev/null
+++ b/lib/spdlog/sinks/wincolor_sink.h
@@ -0,0 +1,144 @@
+//
+// Copyright(c) 2016 spdlog
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+//
+
+#pragma once
+
+#include "../common.h"
+#include "../details/null_mutex.h"
+#include "base_sink.h"
+
+#include <mutex>
+#include <string>
+#include <unordered_map>
+#include <wincon.h>
+
+namespace spdlog {
+namespace sinks {
+/*
+ * Windows color console sink. Uses WriteConsoleA to write to the console with colors
+ */
+template<class Mutex>
+class wincolor_sink : public base_sink<Mutex>
+{
+public:
+    const WORD BOLD = FOREGROUND_INTENSITY;
+    const WORD RED = FOREGROUND_RED;
+    const WORD GREEN = FOREGROUND_GREEN;
+    const WORD CYAN = FOREGROUND_GREEN | FOREGROUND_BLUE;
+    const WORD WHITE = FOREGROUND_RED | FOREGROUND_GREEN | FOREGROUND_BLUE;
+    const WORD YELLOW = FOREGROUND_RED | FOREGROUND_GREEN;
+
+    wincolor_sink(HANDLE std_handle)
+        : out_handle_(std_handle)
+    {
+        colors_[level::trace] = WHITE;
+        colors_[level::debug] = CYAN;
+        colors_[level::info] = GREEN;
+        colors_[level::warn] = YELLOW | BOLD;
+        colors_[level::err] = RED | BOLD;                         // red bold
+        colors_[level::critical] = BACKGROUND_RED | WHITE | BOLD; // white bold on red background
+        colors_[level::off] = 0;
+    }
+
+    ~wincolor_sink() override
+    {
+        this->flush();
+    }
+
+    wincolor_sink(const wincolor_sink &other) = delete;
+    wincolor_sink &operator=(const wincolor_sink &other) = delete;
+
+    // change the color for the given level
+    void set_color(level::level_enum level, WORD color)
+    {
+        std::lock_guard<Mutex> lock(base_sink<Mutex>::_mutex);
+        colors_[level] = color;
+    }
+
+protected:
+    void _sink_it(const details::log_msg &msg) override
+    {
+        if (msg.color_range_end > msg.color_range_start)
+        {
+            // before color range
+            _print_range(msg, 0, msg.color_range_start);
+
+            // in color range
+            auto orig_attribs = set_console_attribs(colors_[msg.level]);
+            _print_range(msg, msg.color_range_start, msg.color_range_end);
+            ::SetConsoleTextAttribute(out_handle_, orig_attribs); // reset to orig colors
+            // after color range
+            _print_range(msg, msg.color_range_end, msg.formatted.size());
+        }
+        else // print without colors if color range is invalid
+        {
+            _print_range(msg, 0, msg.formatted.size());
+        }
+    }
+
+    void _flush() override
+    {
+        // windows console always flushed?
+    }
+
+private:
+    HANDLE out_handle_;
+    std::unordered_map<level::level_enum, WORD, level::level_hasher> colors_;
+
+    // set color and return the orig console attributes (for resetting later)
+    WORD set_console_attribs(WORD attribs)
+    {
+        CONSOLE_SCREEN_BUFFER_INFO orig_buffer_info;
+        GetConsoleScreenBufferInfo(out_handle_, &orig_buffer_info);
+        WORD back_color = orig_buffer_info.wAttributes;
+        // retrieve the current background color
+        back_color &= static_cast<WORD>(~(FOREGROUND_RED | FOREGROUND_GREEN | FOREGROUND_BLUE | FOREGROUND_INTENSITY));
+        // keep the background color unchanged
+        SetConsoleTextAttribute(out_handle_, attribs | back_color);
+        return orig_buffer_info.wAttributes; // return orig attribs
+    }
+
+    // print a range of formatted message to console
+    void _print_range(const details::log_msg &msg, size_t start, size_t end)
+    {
+        DWORD size = static_cast<DWORD>(end - start);
+        WriteConsoleA(out_handle_, msg.formatted.data() + start, size, nullptr, nullptr);
+    }
+};
+
+//
+// windows color console to stdout
+//
+template<class Mutex>
+class wincolor_stdout_sink : public wincolor_sink<Mutex>
+{
+public:
+    wincolor_stdout_sink()
+        : wincolor_sink<Mutex>(GetStdHandle(STD_OUTPUT_HANDLE))
+    {
+    }
+};
+
+using wincolor_stdout_sink_mt = wincolor_stdout_sink<std::mutex>;
+using wincolor_stdout_sink_st = wincolor_stdout_sink<details::null_mutex>;
+
+//
+// windows color console to stderr
+//
+template<class Mutex>
+class wincolor_stderr_sink : public wincolor_sink<Mutex>
+{
+public:
+    wincolor_stderr_sink()
+        : wincolor_sink<Mutex>(GetStdHandle(STD_ERROR_HANDLE))
+    {
+    }
+};
+
+using wincolor_stderr_sink_mt = wincolor_stderr_sink<std::mutex>;
+using wincolor_stderr_sink_st = wincolor_stderr_sink<details::null_mutex>;
+
+} // namespace sinks
+} // namespace spdlog
diff --git a/lib/spdlog/sinks/windebug_sink.h b/lib/spdlog/sinks/windebug_sink.h
new file mode 100644
index 0000000..2c7f1bc
--- /dev/null
+++ b/lib/spdlog/sinks/windebug_sink.h
@@ -0,0 +1,27 @@
+//
+// Copyright(c) 2017 Alexander Dalshov.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+//
+
+#pragma once
+
+#if defined(_WIN32)
+
+#include "msvc_sink.h"
+
+namespace spdlog {
+namespace sinks {
+
+/*
+ * Windows debug sink (logging using OutputDebugStringA, synonym for msvc_sink)
+ */
+template<class Mutex>
+using windebug_sink = msvc_sink<Mutex>;
+
+using windebug_sink_mt = msvc_sink_mt;
+using windebug_sink_st = msvc_sink_st;
+
+} // namespace sinks
+} // namespace spdlog
+
+#endif
diff --git a/lib/spdlog/spdlog.h b/lib/spdlog/spdlog.h
new file mode 100644
index 0000000..21f5951
--- /dev/null
+++ b/lib/spdlog/spdlog.h
@@ -0,0 +1,204 @@
+//
+// Copyright(c) 2015 Gabi Melman.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+//
+// spdlog main header file.
+// see example.cpp for usage example
+
+#pragma once
+
+#include "common.h"
+#include "logger.h"
+
+#include <chrono>
+#include <functional>
+#include <memory>
+#include <string>
+
+namespace spdlog {
+
+//
+// Return an existing logger or nullptr if a logger with such name doesn't exist.
+// example: spdlog::get("my_logger")->info("hello {}", "world");
+//
+std::shared_ptr<logger> get(const std::string &name);
+
+//
+// Set global formatting
+// example: spdlog::set_pattern("%Y-%m-%d %H:%M:%S.%e %l : %v");
+//
+void set_pattern(const std::string &format_string);
+void set_formatter(formatter_ptr f);
+
+//
+// Set global logging level
+//
+void set_level(level::level_enum log_level);
+
+//
+// Set global flush level
+//
+void flush_on(level::level_enum log_level);
+
+//
+// Set global error handler
+//
+void set_error_handler(log_err_handler handler);
+
+//
+// Turn on async mode (off by default) and set the queue size for each async_logger.
+// effective only for loggers created after this call.
+// queue_size: size of queue (must be power of 2):
+//    Each logger will pre-allocate a dedicated queue with queue_size entries upon construction.
+//
+// async_overflow_policy (optional, block_retry by default):
+//    async_overflow_policy::block_retry - if queue is full, block until queue has room for the new log entry.
+//    async_overflow_policy::discard_log_msg - never block and discard any new messages when queue overflows.
+//
+// worker_warmup_cb (optional):
+//     callback function that will be called in worker thread upon start (can be used to init stuff like thread affinity)
+//
+// worker_teardown_cb (optional):
+//     callback function that will be called in worker thread upon exit
+//
+void set_async_mode(size_t queue_size, const async_overflow_policy overflow_policy = async_overflow_policy::block_retry,
+    const std::function<void()> &worker_warmup_cb = nullptr,
+    const std::chrono::milliseconds &flush_interval_ms = std::chrono::milliseconds::zero(),
+    const std::function<void()> &worker_teardown_cb = nullptr);
+
+// Turn off async mode
+void set_sync_mode();
+
+//
+// Create and register multi/single threaded basic file logger.
+// Basic logger simply writes to given file without any limitations or rotations.
+//
+std::shared_ptr<logger> basic_logger_mt(const std::string &logger_name, const filename_t &filename, bool truncate = false);
+std::shared_ptr<logger> basic_logger_st(const std::string &logger_name, const filename_t &filename, bool truncate = false);
+
+//
+// Create and register multi/single threaded rotating file logger
+//
+std::shared_ptr<logger> rotating_logger_mt(
+    const std::string &logger_name, const filename_t &filename, size_t max_file_size, size_t max_files);
+
+std::shared_ptr<logger> rotating_logger_st(
+    const std::string &logger_name, const filename_t &filename, size_t max_file_size, size_t max_files);
+
+//
+// Create file logger which creates new file on the given time (default in midnight):
+//
+std::shared_ptr<logger> daily_logger_mt(const std::string &logger_name, const filename_t &filename, int hour = 0, int minute = 0);
+std::shared_ptr<logger> daily_logger_st(const std::string &logger_name, const filename_t &filename, int hour = 0, int minute = 0);
+
+//
+// Create and register stdout/stderr loggers
+//
+std::shared_ptr<logger> stdout_logger_mt(const std::string &logger_name);
+std::shared_ptr<logger> stdout_logger_st(const std::string &logger_name);
+std::shared_ptr<logger> stderr_logger_mt(const std::string &logger_name);
+std::shared_ptr<logger> stderr_logger_st(const std::string &logger_name);
+//
+// Create and register colored stdout/stderr loggers
+//
+std::shared_ptr<logger> stdout_color_mt(const std::string &logger_name);
+std::shared_ptr<logger> stdout_color_st(const std::string &logger_name);
+std::shared_ptr<logger> stderr_color_mt(const std::string &logger_name);
+std::shared_ptr<logger> stderr_color_st(const std::string &logger_name);
+
+//
+// Create and register a syslog logger
+//
+#ifdef SPDLOG_ENABLE_SYSLOG
+std::shared_ptr<logger> syslog_logger(
+    const std::string &logger_name, const std::string &ident = "", int syslog_option = 0, int syslog_facilty = (1 << 3));
+#endif
+
+#if defined(__ANDROID__)
+std::shared_ptr<logger> android_logger(const std::string &logger_name, const std::string &tag = "spdlog");
+#endif
+
+// Create and register a logger with a single sink
+std::shared_ptr<logger> create(const std::string &logger_name, const sink_ptr &sink);
+
+// Create and register a logger with multiple sinks
+std::shared_ptr<logger> create(const std::string &logger_name, sinks_init_list sinks);
+
+template<class It>
+std::shared_ptr<logger> create(const std::string &logger_name, const It &sinks_begin, const It &sinks_end);
+
+// Create and register a logger with templated sink type
+// Example:
+// spdlog::create<daily_file_sink_st>("mylog", "dailylog_filename");
+template<typename Sink, typename... Args>
+std::shared_ptr<spdlog::logger> create(const std::string &logger_name, Args... args);
+
+// Create and register an async logger with a single sink
+std::shared_ptr<logger> create_async(const std::string &logger_name, const sink_ptr &sink, size_t queue_size,
+    const async_overflow_policy overflow_policy = async_overflow_policy::block_retry,
+    const std::function<void()> &worker_warmup_cb = nullptr,
+    const std::chrono::milliseconds &flush_interval_ms = std::chrono::milliseconds::zero(),
+    const std::function<void()> &worker_teardown_cb = nullptr);
+
+// Create and register an async logger with multiple sinks
+std::shared_ptr<logger> create_async(const std::string &logger_name, sinks_init_list sinks, size_t queue_size,
+    const async_overflow_policy overflow_policy = async_overflow_policy::block_retry,
+    const std::function<void()> &worker_warmup_cb = nullptr,
+    const std::chrono::milliseconds &flush_interval_ms = std::chrono::milliseconds::zero(),
+    const std::function<void()> &worker_teardown_cb = nullptr);
+
+template<class It>
+std::shared_ptr<logger> create_async(const std::string &logger_name, const It &sinks_begin, const It &sinks_end, size_t queue_size,
+    const async_overflow_policy overflow_policy = async_overflow_policy::block_retry,
+    const std::function<void()> &worker_warmup_cb = nullptr,
+    const std::chrono::milliseconds &flush_interval_ms = std::chrono::milliseconds::zero(),
+    const std::function<void()> &worker_teardown_cb = nullptr);
+
+// Register the given logger with the given name
+void register_logger(std::shared_ptr<logger> logger);
+
+// Apply a user defined function on all registered loggers
+// Example:
+// spdlog::apply_all([&](std::shared_ptr<spdlog::logger> l) {l->flush();});
+void apply_all(std::function<void(std::shared_ptr<logger>)> fun);
+
+// Drop the reference to the given logger
+void drop(const std::string &name);
+
+// Drop all references from the registry
+void drop_all();
+
+///////////////////////////////////////////////////////////////////////////////
+//
+// Trace & Debug can be switched on/off at compile time for zero cost debug statements.
+// Uncomment SPDLOG_DEBUG_ON/SPDLOG_TRACE_ON in tweakme.h to enable.
+// SPDLOG_TRACE(..) will also print current file and line.
+//
+// Example:
+// spdlog::set_level(spdlog::level::trace);
+// SPDLOG_TRACE(my_logger, "some trace message");
+// SPDLOG_TRACE(my_logger, "another trace message {} {}", 1, 2);
+// SPDLOG_DEBUG(my_logger, "some debug message {} {}", 3, 4);
+///////////////////////////////////////////////////////////////////////////////
+
+#ifdef SPDLOG_TRACE_ON
+#define SPDLOG_STR_H(x) #x
+#define SPDLOG_STR_HELPER(x) SPDLOG_STR_H(x)
+#ifdef _MSC_VER
+#define SPDLOG_TRACE(logger, ...) logger->trace("[ " __FILE__ "(" SPDLOG_STR_HELPER(__LINE__) ") ] " __VA_ARGS__)
+#else
+#define SPDLOG_TRACE(logger, ...) logger->trace("[ " __FILE__ ":" SPDLOG_STR_HELPER(__LINE__) " ] " __VA_ARGS__)
+#endif
+#else
+#define SPDLOG_TRACE(logger, ...) (void)0
+#endif
+
+#ifdef SPDLOG_DEBUG_ON
+#define SPDLOG_DEBUG(logger, ...) logger->debug(__VA_ARGS__)
+#else
+#define SPDLOG_DEBUG(logger, ...) (void)0
+#endif
+
+} // namespace spdlog
+
+#include "details/spdlog_impl.h"
diff --git a/lib/spdlog/tweakme.h b/lib/spdlog/tweakme.h
new file mode 100644
index 0000000..801e13e
--- /dev/null
+++ b/lib/spdlog/tweakme.h
@@ -0,0 +1,143 @@
+//
+// Copyright(c) 2015 Gabi Melman.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+//
+
+#pragma once
+
+///////////////////////////////////////////////////////////////////////////////
+//
+// Edit this file to squeeze more performance, and to customize supported features
+//
+///////////////////////////////////////////////////////////////////////////////
+
+///////////////////////////////////////////////////////////////////////////////
+// Under Linux, the much faster CLOCK_REALTIME_COARSE clock can be used.
+// This clock is less accurate - can be off by dozens of millis - depending on the kernel HZ.
+// Uncomment to use it instead of the regular clock.
+//
+// #define SPDLOG_CLOCK_COARSE
+///////////////////////////////////////////////////////////////////////////////
+
+///////////////////////////////////////////////////////////////////////////////
+// Uncomment if date/time logging is not needed and never appear in the log pattern.
+// This will prevent spdlog from querying the clock on each log call.
+//
+// WARNING: If the log pattern contains any date/time while this flag is on, the result is undefined.
+//          You must set new pattern(spdlog::set_pattern(..") without any date/time in it
+//
+// #define SPDLOG_NO_DATETIME
+///////////////////////////////////////////////////////////////////////////////
+
+///////////////////////////////////////////////////////////////////////////////
+// Uncomment if thread id logging is not needed (i.e. no %t in the log pattern).
+// This will prevent spdlog from querying the thread id on each log call.
+//
+// WARNING: If the log pattern contains thread id (i.e, %t) while this flag is on, the result is undefined.
+//
+#define SPDLOG_NO_THREAD_ID
+///////////////////////////////////////////////////////////////////////////////
+
+///////////////////////////////////////////////////////////////////////////////
+// Uncomment to prevent spdlog from caching thread ids in thread local storage.
+// By default spdlog saves thread ids in tls to gain a few micros for each call.
+//
+// WARNING: if your program forks, UNCOMMENT this flag to prevent undefined thread ids in the children logs.
+//
+#define SPDLOG_DISABLE_TID_CACHING
+///////////////////////////////////////////////////////////////////////////////
+
+///////////////////////////////////////////////////////////////////////////////
+// Uncomment if logger name logging is not needed.
+// This will prevent spdlog from copying the logger name on each log call.
+//
+#define SPDLOG_NO_NAME
+///////////////////////////////////////////////////////////////////////////////
+
+///////////////////////////////////////////////////////////////////////////////
+// Uncomment to enable the SPDLOG_DEBUG/SPDLOG_TRACE macros.
+//
+// #define SPDLOG_DEBUG_ON
+// #define SPDLOG_TRACE_ON
+///////////////////////////////////////////////////////////////////////////////
+
+///////////////////////////////////////////////////////////////////////////////
+// Uncomment to avoid locking in the registry operations (spdlog::get(), spdlog::drop() spdlog::register()).
+// Use only if your code never modifies concurrently the registry.
+// Note that upon creating a logger the registry is modified by spdlog..
+//
+// #define SPDLOG_NO_REGISTRY_MUTEX
+///////////////////////////////////////////////////////////////////////////////
+
+///////////////////////////////////////////////////////////////////////////////
+// Uncomment to avoid spdlog's usage of atomic log levels
+// Use only if your code never modifies a logger's log levels concurrently by different threads.
+//
+#define SPDLOG_NO_ATOMIC_LEVELS
+///////////////////////////////////////////////////////////////////////////////
+
+///////////////////////////////////////////////////////////////////////////////
+// Uncomment to enable usage of wchar_t for file names on Windows.
+//
+// #define SPDLOG_WCHAR_FILENAMES
+///////////////////////////////////////////////////////////////////////////////
+
+///////////////////////////////////////////////////////////////////////////////
+// Uncomment to override default eol ("\n" or "\r\n" under Linux/Windows)
+//
+// #define SPDLOG_EOL ";-)\n"
+///////////////////////////////////////////////////////////////////////////////
+
+///////////////////////////////////////////////////////////////////////////////
+// Uncomment to use your own copy of the fmt library instead of spdlog's copy.
+// In this case spdlog will try to include <fmt/format.h> so set your -I flag accordingly.
+//
+// #define SPDLOG_FMT_EXTERNAL
+///////////////////////////////////////////////////////////////////////////////
+
+///////////////////////////////////////////////////////////////////////////////
+// Uncomment to use printf-style messages in your logs instead of the usual
+// format-style used by default.
+//
+// #define SPDLOG_FMT_PRINTF
+///////////////////////////////////////////////////////////////////////////////
+
+///////////////////////////////////////////////////////////////////////////////
+// Uncomment to enable syslog (disabled by default)
+//
+// #define SPDLOG_ENABLE_SYSLOG
+///////////////////////////////////////////////////////////////////////////////
+
+///////////////////////////////////////////////////////////////////////////////
+// Uncomment to enable wchar_t support (convert to utf8)
+//
+// #define SPDLOG_WCHAR_TO_UTF8_SUPPORT
+///////////////////////////////////////////////////////////////////////////////
+
+///////////////////////////////////////////////////////////////////////////////
+// Uncomment to prevent child processes from inheriting log file descriptors
+//
+// #define SPDLOG_PREVENT_CHILD_FD
+///////////////////////////////////////////////////////////////////////////////
+
+///////////////////////////////////////////////////////////////////////////////
+// Uncomment if your compiler doesn't support the "final" keyword.
+// The final keyword allows more optimizations in release
+// mode with recent compilers. See GCC's documentation for -Wsuggest-final-types
+// for instance.
+//
+// #define SPDLOG_NO_FINAL
+///////////////////////////////////////////////////////////////////////////////
+
+///////////////////////////////////////////////////////////////////////////////
+// Uncomment to enable message counting feature.
+// Use the %i in the logger pattern to display log message sequence id.
+//
+// #define SPDLOG_ENABLE_MESSAGE_COUNTER
+///////////////////////////////////////////////////////////////////////////////
+
+///////////////////////////////////////////////////////////////////////////////
+// Uncomment to customize level names (e.g. "MT TRACE")
+//
+// #define SPDLOG_LEVEL_NAMES { "MY TRACE", "MY DEBUG", "MY INFO", "MY WARNING", "MY ERROR", "MY CRITICAL", "OFF" }
+///////////////////////////////////////////////////////////////////////////////
diff --git a/modules/modpy/Makefile.am b/modules/modpy/Makefile.am
index eccb2a2..231031a 100644
--- a/modules/modpy/Makefile.am
+++ b/modules/modpy/Makefile.am
@@ -10,8 +10,8 @@ mod_py_la_SOURCES       = \
 	py.h py.cpp \
 	interface.h interface.cpp
 
-AM_CPPFLAGS             = -I$(top_srcdir)/lib -I$(top_srcdir)/src \
-	${PYTHON_INCLUDES} ${libconfig_CFLAGS} ${log4cpp_CFLAGS}
+AM_CPPFLAGS             = -std=c++11 -I$(top_srcdir)/lib -I$(top_srcdir)/src \
+	${PYTHON_INCLUDES} ${libconfig_CFLAGS}
 
 mod_py_la_LIBADD        = ${PYTHON_LIBS}
 endif
diff --git a/modules/modpy/interface.cpp b/modules/modpy/interface.cpp
index 948fa5c..60e1c7b 100644
--- a/modules/modpy/interface.cpp
+++ b/modules/modpy/interface.cpp
@@ -19,10 +19,11 @@
 
 #include "interface.h"
 
-#include <bitz/logger.h>
 #include <icap/request.h>
 #include <icap/response.h>
-#include <iostream>
+#include <spdlog/spdlog.h>
+
+static auto _logger = spdlog::get( "bitz-server" );
 
 
 PyObject * bitz_get_request( PyObject * self, PyObject * pyrequest ) {
@@ -31,9 +32,7 @@ PyObject * bitz_get_request( PyObject * self, PyObject * pyrequest ) {
 	PyObject * pypayload;
 	icap::Request * request;
 
-	// logger
-	bitz::Logger &logger = bitz::Logger::instance();
-	logger.debug( "[modpy.interface] get_request()" );
+	_logger->debug( "[modpy.interface] get_request()" );
 
 	// initialise return dictionary
 	pyreturn = PyDict_New();
@@ -65,7 +64,7 @@ PyObject * bitz_get_request( PyObject * self, PyObject * pyrequest ) {
 		Py_DECREF( pypayload );
 
 	} else {
-		logger.warn( "[modpy.interface] failed to get request object pointer" );
+		_logger->warn( "[modpy.interface] failed to get request object pointer" );
 	}
 
 	return pyreturn;
@@ -80,15 +79,13 @@ PyObject * bitz_get_response_from_status( PyObject * self, PyObject * args ) {
 
 	unsigned int resp_status;
 
-	// logger
-	bitz::Logger &logger = bitz::Logger::instance();
-	logger.debug( "[modpy.interface] get_response_from_status()" );
+	_logger->debug( "[modpy.interface] get_response_from_status()" );
 
 	// parse args
 	if ( PyArg_ParseTuple( args, "I", &resp_status ) ) {
 		response = new icap::Response( (icap::ResponseHeader::status_t) resp_status );
 	} else {
-		logger.warn( "[modpy.interface] failed to parse arguments" );
+		_logger->warn( "[modpy.interface] failed to parse arguments" );
 		response = new icap::Response( icap::ResponseHeader::SERVER_ERROR );
 	}
 
@@ -114,9 +111,7 @@ PyObject * bitz_get_response( PyObject * self, PyObject * args ) {
 	Py_ssize_t pybuflen;
 
 
-	// logger
-	bitz::Logger &logger = bitz::Logger::instance();
-	logger.debug( "[modpy.interface] get_response()" );
+	_logger->debug( "[modpy.interface] get_response()" );
 
 	// parse args
 	if ( PyArg_ParseTuple( args, "IO!", &resp_status, &PyDict_Type, &pypayload ) ) {
@@ -142,7 +137,7 @@ PyObject * bitz_get_response( PyObject * self, PyObject * args ) {
 		response->payload( payload );
 
 	} else {
-		logger.warn( "[modpy.interface] failed to parse arguments" );
+		_logger->warn( "[modpy.interface] failed to parse arguments" );
 	}
 
 	// sanity check
diff --git a/modules/modpy/py.cpp b/modules/modpy/py.cpp
index 51cb38f..a1d330d 100644
--- a/modules/modpy/py.cpp
+++ b/modules/modpy/py.cpp
@@ -21,7 +21,6 @@
 #include "interface.h"
 
 #include <bitz/config.h>
-#include <bitz/logger.h>
 
 
 namespace bitz {
@@ -35,6 +34,9 @@ namespace bitz {
 		_config.module_name = "modpy";
 		_config.module_path = "";
 
+		// logger
+		_logger = spdlog::get( "bitz-server" );
+
 		// load configs
 		load_configs();
 
@@ -92,21 +94,19 @@ namespace bitz {
 		PyObject * pymethod;
 		PyObject * pyreturn;
 
-		// logger
-		Logger &logger = Logger::instance();
 
 		// python core
 		Py_Initialize();
 
 		// bitz python module
 		if ( Py_InitModule( "bitz", bitz_methods ) == NULL ) {
-			logger.warn( "[modpy] failed to init C interface module: bitz" );
+			_logger->warn( "[modpy] failed to init C interface module: bitz" );
 		}
 
 		// setup python environment
 		if ( _config.module_path != "" ) {
 
-			logger.debug( std::string( "[modpy] appending to sys.path, module_path: " ).append( _config.module_path ) );
+			_logger->debug( std::string( "[modpy] appending to sys.path, module_path: " ).append( _config.module_path ) );
 
 			sys_path      = PySys_GetObject( (char *) "path" );
 			pymodule_path = PyString_FromString( _config.module_path.c_str() );
@@ -115,14 +115,14 @@ namespace bitz {
 		}
 
 		// load the interface module
-		logger.debug( std::string( "[modpy] interface module: " ).append( _config.module_name ) );
+		_logger->debug( std::string( "[modpy] interface module: " ).append( _config.module_name ) );
 
 		pymodule_name = PyString_FromString( _config.module_name.c_str() );
 		_pymodule     = PyImport_Import( pymodule_name );
 
 		if ( _pymodule != NULL ) {
 
-			logger.debug( "[modpy] interface module loaded successfully" );
+			_logger->debug( "[modpy] interface module loaded successfully" );
 
 			// call init() in the interface module
 			pymethod = PyObject_GetAttrString( _pymodule, "init" );
@@ -131,13 +131,13 @@ namespace bitz {
 				pyreturn = PyObject_CallObject( pymethod, NULL );
 				Py_DECREF( pyreturn );
 			} else {
-				logger.warn ( "[modpy] failed to call init() in interface module" );
+				_logger->warn ( "[modpy] failed to call init() in interface module" );
 			}
 
 			Py_DECREF( pymethod );
 
 		} else {
-			logger.warn( "[modpy] failed to load interface module" );
+			_logger->warn( "[modpy] failed to load interface module" );
 		}
 
 
@@ -154,9 +154,6 @@ namespace bitz {
 		PyObject * pymethod;
 		PyObject * pyreturn;
 
-		// logger
-		Logger &logger = Logger::instance();
-
 
 		// cleanup
 		if ( _pymodule != NULL ) {
@@ -168,7 +165,7 @@ namespace bitz {
 				pyreturn = PyObject_CallObject( pymethod, NULL );
 				Py_DECREF( pyreturn );
 			} else {
-				logger.warn ( "[modpy] failed to call cleanup() in interface module" );
+				_logger->warn ( "[modpy] failed to call cleanup() in interface module" );
 			}
 
 			Py_DECREF( pymethod );
@@ -199,9 +196,6 @@ namespace bitz {
 		PyObject * pyargs;
 		PyObject * pyrequest, * pyresponse;
 
-		// logger
-		Logger &logger = Logger::instance();
-
 		// initialise the response object
 		response = NULL;
 
@@ -231,18 +225,18 @@ namespace bitz {
 						response = static_cast<icap::Response *>(p);
 
 					} else {
-						logger.warn( std::string( "[modpy] invalid capsule response, method: " ).append( method ) );
+						_logger->warn( std::string( "[modpy] invalid capsule response, method: " ).append( method ) );
 					}
 
 					Py_DECREF( pyresponse );
 
 				} else {
-					logger.warn( std::string( "[modpy] response is NULL, method: " ).append( method ) );
+					_logger->warn( std::string( "[modpy] response is NULL, method: " ).append( method ) );
 				}
 
 
 			} else {
-				logger.warn ( std::string( "[modpy] failed to call the method in interface module, method: " ).append( method ) );
+				_logger->warn ( std::string( "[modpy] failed to call the method in interface module, method: " ).append( method ) );
 			}
 
 			// cleanup
diff --git a/modules/modpy/py.h b/modules/modpy/py.h
index 358c36f..f171063 100644
--- a/modules/modpy/py.h
+++ b/modules/modpy/py.h
@@ -23,6 +23,7 @@
 #include <Python.h>
 
 #include <bitz/modifier.h>
+#include <spdlog/spdlog.h>
 
 
 namespace bitz {
@@ -44,6 +45,7 @@ namespace bitz {
 	private:
 		config_t _config;
 		PyObject * _pymodule;
+		std::shared_ptr<spdlog::logger> _logger;
 
 		void load_configs() throw();
 		void init_python() throw();
diff --git a/src/Makefile.am b/src/Makefile.am
index b3038cd..15a6efc 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -1,12 +1,15 @@
 ## src/
 AUTOMAKE_OPTIONS        = subdir-objects
-AM_CPPFLAGS             = -I$(top_srcdir)/lib ${libconfig_CFLAGS} ${log4cpp_CFLAGS} ${psocksxx_CFLAGS}
+AM_CPPFLAGS             = -std=c++11 \
+	-I$(top_srcdir)/lib \
+	${libconfig_CFLAGS} \
+	${psocksxx_CFLAGS}
 
 bitzincludedir          = $(pkgincludedir)
 sbin_PROGRAMS           = bitz-server
-bitz_server_LDFLAGS     = -ldl -export-dynamic
+bitz_server_LDFLAGS     = -ldl -lpthread -export-dynamic
 bitz_server_LDADD       = $(top_builddir)/lib/icap/libicap.la \
-	${libconfig_LIBS} ${log4cpp_LIBS} \
+	${libconfig_LIBS} \
 	${psocksxx_LIBS}
 
 bitz_server_SOURCES     = main.cpp \
@@ -14,7 +17,6 @@ bitz_server_SOURCES     = main.cpp \
 	bitz/exception.h bitz/exception.cpp \
 	bitz/manager_exception.h bitz/manager_exception.cpp \
 	bitz/config.h bitz/config.cpp \
-	bitz/logger.h bitz/logger.cpp \
 	bitz/common.h \
 	bitz/util.h bitz/util.cpp \
 	bitz/manager.h bitz/manager.cpp \
@@ -27,6 +29,5 @@ bitz_server_SOURCES     = main.cpp \
 
 bitzinclude_HEADERS     = \
 	bitz/config.h \
-	bitz/logger.h \
 	bitz/modifier.h
 
diff --git a/src/bitz-server.cpp b/src/bitz-server.cpp
index d6257fd..e99078e 100644
--- a/src/bitz-server.cpp
+++ b/src/bitz-server.cpp
@@ -29,6 +29,8 @@
 #include <sys/stat.h>
 #include <sys/wait.h>
 
+#include <spdlog/spdlog.h>
+
 #include <config.h>
 #include "bitz-server.h"
 
@@ -41,15 +43,12 @@ namespace bitz {
 		void init() {
 
 			// initialise defaults
-			globals.pid_handle  = -1;
+			globals.pid         = -1;
+			globals.pidfd       = -1;
 			globals.manager     = NULL;
 			globals.terminating = 0;
 			globals.daemon      = false;
 
-			// logger (syslog)
-			setlogmask( LOG_UPTO( LOG_INFO ) );
-			openlog( PACKAGE_NAME, LOG_CONS, LOG_USER );
-
 			// signal handlers
 			init_signal_handlers();
 
@@ -100,9 +99,10 @@ namespace bitz {
 			pid_t worker_pid;
 			int status;
 
-			std::cout << "[" << getpid() << "] inside zombie deleter: ";
+			auto logger = spdlog::get( "bitz-server" );
+			logger->trace( "[{}] inside zombie reaper", getpid() );
 			while ( ( worker_pid = waitpid( WAIT_ANY, &status, WNOHANG ) ) > 0 ) {
-				std::cout << "child " << worker_pid << " terminated with status " << status << std::endl;
+				logger->trace( "[reaper] child {} terminated with status {}", worker_pid, status );
 
 				if ( globals.manager != NULL ) {
 					globals.manager->reap_worker( worker_pid );
@@ -134,7 +134,8 @@ namespace bitz {
 
 		void sigterm_handler( int sig, siginfo_t *siginfo, void *context ) {
 
-			std::cout << "[" << getpid() << "] inside SIGTERM handler" << std::endl;
+			auto logger = spdlog::get( "bitz-server" );
+			logger->trace( "[{}] inside SIGTERM handler", getpid() );
 			termination_handler( sig, siginfo, context );
 
 		}
@@ -162,7 +163,8 @@ namespace bitz {
 
 		void sigquit_handler( int sig, siginfo_t *siginfo, void *context ) {
 
-			std::cout << "[" << getpid() << "] inside SIGQUIT handler" << std::endl;
+			auto logger = spdlog::get( "bitz-server" );
+			logger->trace( "[{}] inside SIGQUIT handler", getpid() );
 			termination_handler( sig, siginfo, context );
 
 		}
@@ -190,7 +192,8 @@ namespace bitz {
 
 		void sigint_handler(  int sig, siginfo_t *siginfo, void *context ) {
 
-			std::cout << "[" << getpid() << "] inside SIGQINT handler" << std::endl;
+			auto logger = spdlog::get( "bitz-server" );
+			logger->trace( "[{}] inside SIGQINT handler", getpid() );
 			termination_handler( sig, siginfo, context );
 
 		}
@@ -198,20 +201,28 @@ namespace bitz {
 
 		void daemonize( const char *rundir, const char *pidfile ) {
 
-			pid_t pid, sid;
+			pid_t pid;
 			long i;
 			char str[10];
 
-			// notify
-			syslog( LOG_NOTICE, "starting daemon (version %s)", PACKAGE_VERSION );
+			/* fork daemon */
+			pid = fork();
+			if ( pid < 0 ) {
+				exit( EXIT_FAILURE );
+			}
 
-			// check parent process id value
-			if ( getppid() == 1 ) {
-				// we are already a daemon
-				return;
+			// exit the parent
+			if ( pid > 0 ) {
+				exit( EXIT_SUCCESS );
 			}
 
-			/* fork daemon */
+			// get a new process group
+			if ( setsid() < 0 ) {
+				exit(EXIT_FAILURE);
+			}
+
+
+			// 2nd fork (to make PID != SID)
 			pid = fork();
 			if ( pid < 0 ) {
 				exit( EXIT_FAILURE );
@@ -224,63 +235,67 @@ namespace bitz {
 
 
 			/* child (a.k.a daemon) continues */
-
 			// set file permissions (750)
 			umask( 027 );
 
-			// get a new process group
-			sid = setsid();
-			if ( sid < 0 ) {
-				exit(EXIT_FAILURE);
+			// change running directory
+			chdir( rundir );
+
+			// close all open file descriptors
+			for ( int fd = sysconf( _SC_OPEN_MAX ); fd > 0; fd-- ) {
+				close( fd );
 			}
 
-			// route I/O connections
-			close( STDIN_FILENO );
-			close( STDOUT_FILENO );
-			close( STDERR_FILENO );
 
-			// change running directory
-			chdir( rundir );
+			// logger (syslog)
+			setlogmask( LOG_UPTO( LOG_INFO ) );
+			openlog( PACKAGE_NAME, LOG_CONS, LOG_USER );
+
+			// notify
+			syslog( LOG_NOTICE, "starting daemon (version %s)", PACKAGE_VERSION );
 
 
 			/* lock pid file to ensure we have only one copy */
 
-			globals.pid_handle = open( pidfile, O_RDWR | O_CREAT, 0600 );
-			if ( globals.pid_handle == -1 ) {
+			globals.pidfd = open( pidfile, O_RDWR | O_CREAT, 0600 );
+			if ( globals.pidfd == -1 ) {
 				syslog( LOG_ERR, "could not open pid lock file: %s", pidfile );
 				exit( EXIT_FAILURE );
 			}
 
-			if ( lockf( globals.pid_handle, F_TLOCK, 0 ) == -1 ) {
+			if ( lockf( globals.pidfd, F_TLOCK, 0 ) == -1 ) {
 				syslog( LOG_ERR, "could not lock pid lock file: %s", pidfile);
 				exit( EXIT_FAILURE );
 			}
 
 			// get and format pid
-			sprintf( str, "%d\n", getpid() );
+			globals.pid = getpid();
+			sprintf( str, "%d\n", globals.pid );
 
 			// write pid to lockfile
-			write( globals.pid_handle, str, strlen( str ) );
+			write( globals.pidfd, str, strlen( str ) );
 
 			// update status
 			globals.daemon = true;
 
-
 		}
 
 
 		void shutdown() {
 
 			// notify
-			if ( globals.daemon && ( getppid() == 1 ) ) {
+			if ( globals.daemon && ( getpid() == globals.pid ) ) {
 				syslog( LOG_NOTICE, "shutting down daemon (version %s)", PACKAGE_VERSION );
 			}
 
 			// close pid file
-			if ( globals.pid_handle != -1 ) {
-				close( globals.pid_handle );
+			if ( globals.pidfd != -1 ) {
+				close( globals.pidfd );
 			}
 
+			// flush logs
+			spdlog::get( "bitz-server" )->flush();
+
 			// close logger (syslog)
 			closelog();
 
@@ -289,12 +304,15 @@ namespace bitz {
 
 		void termination_handler( int sig, siginfo_t * sig_info, void * context ) {
 
-			std::cout << "[" << getpid() << "] inside termination handler" << std::endl;
+			pid_t pid = getpid();
+			auto logger = spdlog::get( "bitz-server" );
+			logger->trace( "[{}] inside termination handler", pid );
 
 			// exit by re-raising the signal if termination
 			// already in progress
 			if ( globals.terminating ) {
-				std::cout << "[" << getpid() << "] already terminating" << std::endl;
+				logger->warn( "[{}] already terminating", pid );
+
 				raise( sig );
 			}
 
@@ -455,7 +473,7 @@ namespace bitz {
 				sigprocmask( SIG_UNBLOCK, &mask, NULL );
 
 				// manage workers
-				globals.manager->manager_workers();
+				globals.manager->manage_workers();
 
 				// block termination signals
 				sigprocmask( SIG_BLOCK, &mask, &oldmask );
diff --git a/src/bitz-server.h b/src/bitz-server.h
index c7dda05..2a4b57f 100644
--- a/src/bitz-server.h
+++ b/src/bitz-server.h
@@ -23,6 +23,7 @@
 #include "bitz/manager.h"
 
 #include <csignal>
+#include <sys/types.h>
 
 
 namespace bitz {
@@ -34,7 +35,8 @@ namespace bitz {
 		*   by the init() method.
 		*/
 		struct server_t {
-			int pid_handle;
+			pid_t pid;
+			int pidfd;
 			volatile sig_atomic_t terminating;
 			bool daemon;
 
diff --git a/src/bitz/config.cpp b/src/bitz/config.cpp
index aaa247f..f5ef810 100644
--- a/src/bitz/config.cpp
+++ b/src/bitz/config.cpp
@@ -18,9 +18,7 @@
  */
 
 #include "config.h"
-#include "logger.h"
 
-#include <iostream>
 #include <cstdlib>
 
 
@@ -32,7 +30,6 @@ namespace bitz {
 		_config.port            = 1344;
 		_config.pid_file        = "/dev/null";
 		_config.log_file        = "/dev/null";
-		_config.log_category    = "bitz";
 		_config.req_handlers_count = 0;
 		_config.req_handlers       = NULL;
 
@@ -44,6 +41,9 @@ namespace bitz {
 		// defaults
 		_lconfig = NULL;
 
+		// logger
+		_logger = spdlog::get( "bitz-server" );
+
 	}
 
 	Config::~Config() {
@@ -72,12 +72,10 @@ namespace bitz {
 		try {
 			config->readFile( config_file.c_str() );
 		} catch ( const libconfig::FileIOException &ex ) {
-			std::cerr << "[config] failed to read config file: " << config_file
-					<< ", exception: " << ex.what() << std::endl;
+			_logger->error( "[config] failed to read config file: {}, exception: {}",  config_file, ex.what() );
 			exit( EXIT_FAILURE );
 		} catch ( const libconfig::ParseException &pex ) {
-			std::cerr << "[config] parse error at " << pex.getFile()
-					<< ":" << pex.getLine() << " - " << pex.getError() << std::endl;
+			_logger->error( "[config] parse error at {}:{} - {}", pex.getFile(), pex.getLine(), pex.getError() );
 			exit( EXIT_FAILURE );
 		}
 
@@ -87,7 +85,6 @@ namespace bitz {
 			config->lookupValue( "port", _config.port );
 			config->lookupValue( "pid_file", _config.pid_file );
 			config->lookupValue( "log_file", _config.log_file );
-			config->lookupValue( "log_category", _config.log_category );
 
 			config->lookupValue( "max_workers", _config.max_workers );
 			config->lookupValue( "max_worker_requests", _config.max_worker_requests );
@@ -95,8 +92,7 @@ namespace bitz {
 			config->lookupValue( "comm_timeout", _config.comm_timeout );
 
 		} catch ( const libconfig::SettingNotFoundException &e ) {
-			std::cerr << "[config] failed to load core configs, "
-					<< e.getPath() << " : " << e.what() << std::endl;
+			_logger->error( "[config] failed to load core configs, {} : {}", e.getPath(), e.what() );
 		}
 
 		// cache configs
@@ -125,12 +121,11 @@ namespace bitz {
 				libconfig::Setting &setting = _lconfig->lookup( std::string( "modules." ).append( module ) );
 				setting.lookupValue( config, config_value );
 			} catch ( const libconfig::SettingNotFoundException &e ) {
-				// TODO: log errors ??
-				std::cerr << "[config] " << e.getPath() << " : " << e.what() << std::endl;
+				_logger->error( "[config] {} : {}", e.getPath(), e.what() );
 			}
 
 		} else {
-			std::cout << "[config] 'modules' configs not found" << std::endl;
+			_logger->info( "[config] 'modules' configs not found" );
 		}
 
 		return config_value;
@@ -143,16 +138,14 @@ namespace bitz {
 		int i, j;
 		std::string s;
 
-		std::cout << "[config] looking for req_handlers... ";
+		_logger->trace( "[config] looking for req_handlers" );
 		if ( _lconfig->exists( "req_handlers" ) ) {
 
-			std::cout << "found ";
-
 			libconfig::Setting &req_handlers = _lconfig->lookup( "req_handlers" );
 			_config.req_handlers_count       = req_handlers.getLength();
 			_config.req_handlers             = new req_handlers_config_t[_config.req_handlers_count];
 
-			std::cout << "(" << _config.req_handlers_count << ")" << std::endl;
+			_logger->debug( "[config] found {} request handlers", _config.req_handlers_count );
 
 			try {
 
@@ -162,29 +155,28 @@ namespace bitz {
 					_config.req_handlers[i].class_name = (const char *) req_handlers[i]["class"];
 
 					// read request handler modules config
-					std::cout << "[config] looking for " << _config.req_handlers[i].name << " modules... ";
+					_logger->debug( "[config] looking for {} modules", _config.req_handlers[i].name );
 					if ( req_handlers[i].exists( "modules" ) ) {
-						std::cout << "found ";
 
 						_config.req_handlers[i].modules_count   = req_handlers[i]["modules"].getLength();
 						_config.req_handlers[i].modules         = new modules_config_t[_config.req_handlers[i].modules_count];
 
-						std::cout << "(" << _config.req_handlers[i].modules_count << ")" << std::endl;
+						_logger->debug( "[config] found {} modules for {}", _config.req_handlers[i].modules_count, _config.req_handlers[i].name );
 						for ( j = 0; j < _config.req_handlers[i].modules_count; j++ ) {
 							_config.req_handlers[i].modules[j].name   = (const char *) req_handlers[i]["modules"][j]["name"];
 							_config.req_handlers[i].modules[j].module = (const char *) req_handlers[i]["modules"][j]["module"];
 						}
 					} else {
-						std::cout << "not found" << std::endl;
+						_logger->info( "[config] no modules found for {}", _config.req_handlers[i].name );
 					}
 				}
 
 			} catch ( const libconfig::SettingNotFoundException &ex ) {
-				std::cerr << "[config] Error: " << ex.getPath() << ex.what() << std::endl;
+				_logger->error( "[config] {} : {}", ex.getPath(), ex.what() );
 			}
 
 		} else {
-			std::cout << "not found" << std::endl;
+			_logger->info( "[config] no request handlers found" );
 		}
 
 	}
diff --git a/src/bitz/config.h b/src/bitz/config.h
index 021384b..06cd4df 100644
--- a/src/bitz/config.h
+++ b/src/bitz/config.h
@@ -22,6 +22,7 @@
 
 #include <string>
 #include <libconfig.h++>
+#include <spdlog/spdlog.h>
 
 
 #ifndef BITZ_SERVER_CONFIG_FILE
@@ -50,7 +51,6 @@ namespace bitz {
 		int comm_timeout;
 		std::string pid_file;
 		std::string log_file;
-		std::string log_category;
 		unsigned int req_handlers_count;
 
 		req_handlers_config_t * req_handlers;
@@ -80,6 +80,7 @@ namespace bitz {
 	private:
 		config_t _config;
 		libconfig::Config * _lconfig;
+		std::shared_ptr<spdlog::logger> _logger;
 
 		Config();
 		~Config();
diff --git a/src/bitz/logger.cpp b/src/bitz/logger.cpp
deleted file mode 100644
index 1d7d833..0000000
--- a/src/bitz/logger.cpp
+++ /dev/null
@@ -1,98 +0,0 @@
-/*
- *	bitz-server, An ICAP server implementation in C++
- *	Copyright (C) 2012	Uditha Atukorala
- *
- *	This program is free software; you can redistribute it and/or modify
- *	it under the terms of the GNU General Public License as published by
- *	the Free Software Foundation; either version 3 of the License, or
- *	(at your option) any later version.
- *
- *	This program is distributed in the hope that it will be useful,
- *	but WITHOUT ANY WARRANTY; without even the implied warranty of
- *	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- *	GNU General Public License for more details.
- *
- *	You should have received a copy of the GNU General Public License
- *	along with this program; if not, write to the Free Software
- *	Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
- */
-
-#include "logger.h"
-
-#include <log4cpp/FileAppender.hh>
-#include <log4cpp/PatternLayout.hh>
-
-namespace bitz {
-
-	Logger::Logger( std::string log_file, std::string category ) {
-		this->LOGGER = NULL;
-		this->initialise( log_file, category );
-	}
-
-	Logger::~Logger() {
-		this->LOGGER->debug( "closing down logger" );
-	}
-
-	void Logger::initialise( std::string log_file, std::string category ) {
-
-		this->LOGGER = &log4cpp::Category::getInstance( category );
-
-		// setting up appender, layout and category
-		log4cpp::Appender * log_appender    = new log4cpp::FileAppender( "FileAppender", log_file );
-		log4cpp::PatternLayout * log_layout = new log4cpp::PatternLayout();
-		log_layout->setConversionPattern( "%d %p %c %x: %m%n" );
-
-		log_appender->setLayout( log_layout );
-		this->LOGGER->setAppender( log_appender );
-		this->LOGGER->setPriority( this->getPriorityValue( "DEBUG" ) );
-
-		this->LOGGER->debug( "logger initialised, log_file: " + log_file );
-
-	}
-
-	int Logger::getPriorityValue( const std::string &priority ) {
-		return ( log4cpp::Priority::getPriorityValue( priority ) );
-	}
-
-	void Logger::log( log4cpp::Priority::Value priority, const std::string &message ) {
-		this->LOGGER->log( priority, message );
-	}
-
-	void Logger::fatal( const std::string& message ) {
-		this->LOGGER->fatal( message );
-	}
-
-	void Logger::emerg( const std::string& message ) {
-		this->LOGGER->emerg( message );
-	}
-
-	void Logger::alert( const std::string& message ) {
-		this->LOGGER->alert( message );
-	}
-
-	void Logger::crit( const std::string& message ) {
-		this->LOGGER->crit( message );
-	}
-
-	void Logger::error( const std::string& message ) {
-		this->LOGGER->error( message );
-	}
-
-	void Logger::warn( const std::string& message ) {
-		this->LOGGER->warn( message );
-	}
-
-	void Logger::notice( const std::string& message ) {
-		this->LOGGER->notice( message );
-	}
-
-	void Logger::info( const std::string& message ) {
-		this->LOGGER->info( message );
-	}
-
-	void Logger::debug( const std::string& message ) {
-		this->LOGGER->debug( message );
-	}
-
-} /* end of namespace bitz */
-
diff --git a/src/bitz/logger.h b/src/bitz/logger.h
deleted file mode 100644
index f1c9c6c..0000000
--- a/src/bitz/logger.h
+++ /dev/null
@@ -1,62 +0,0 @@
-/*
- *	bitz-server, An ICAP server implementation in C++
- *	Copyright (C) 2012	Uditha Atukorala
- *
- *	This program is free software; you can redistribute it and/or modify
- *	it under the terms of the GNU General Public License as published by
- *	the Free Software Foundation; either version 3 of the License, or
- *	(at your option) any later version.
- *
- *	This program is distributed in the hope that it will be useful,
- *	but WITHOUT ANY WARRANTY; without even the implied warranty of
- *	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- *	GNU General Public License for more details.
- *
- *	You should have received a copy of the GNU General Public License
- *	along with this program; if not, write to the Free Software
- *	Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
- */
-
-#ifndef BITZ_LOGGER_H
-#define BITZ_LOGGER_H
-
-#include <string>
-#include <log4cpp/Category.hh>
-
-namespace bitz {
-
-	class Logger {
-	public:
-		static Logger &instance( std::string log_file = "/dev/null" , std::string category = "logger" ) {
-			static Logger logger( log_file, category );
-			return logger;
-		}
-
-		void initialise( std::string log_file, std::string category );
-
-		static int getPriorityValue( const std::string& priority );
-		void log( int priority, const std::string &message );
-
-		void fatal( const std::string& message );
-		void emerg( const std::string& message );
-		void alert( const std::string& message );
-		void crit( const std::string& message );
-		void error( const std::string& message );
-		void warn( const std::string& message );
-		void notice( const std::string& message );
-		void info( const std::string& message );
-		void debug( const std::string& message );
-
-	private:
-		log4cpp::Category * LOGGER;
-
-		Logger( std::string log_file, std::string category );
-		~Logger();
-		Logger( Logger const &copy );
-		Logger &operator=( const Logger &copy );
-	};
-
-} /* end of namespace bitz */
-
-#endif /* !BITZ_LOGGER_H */
-
diff --git a/src/bitz/manager.cpp b/src/bitz/manager.cpp
index 14033a5..38b431f 100644
--- a/src/bitz/manager.cpp
+++ b/src/bitz/manager.cpp
@@ -18,7 +18,6 @@
  */
 
 #include "manager.h"
-#include "logger.h"
 #include "util.h"
 
 #include <cstdlib>
@@ -55,20 +54,19 @@ namespace bitz {
 			throw ManagerException( std::string( "failed to initialise socket, " ).append( e.what() ) );
 		}
 
-		Logger &logger = Logger::instance();
-		logger.debug( "manager initialised" );
+		// logger
+		_logger = spdlog::get( "bitz-server" );
+		_logger->debug( "manager initialised" );
 
 	}
 
 
 	Manager::~Manager() {
 
-		Logger &logger = Logger::instance();
-
 		if ( _manager.worker ) {
-			logger.debug( "[worker] cleaning up manager" );
+			_logger->debug( "[worker] cleaning up manager" );
 		} else {
-			logger.debug( "[manager] shutting down manager" );
+			_logger->debug( "[manager] shutting down manager" );
 		}
 
 		delete [] _manager.worker_pool;
@@ -102,7 +100,6 @@ namespace bitz {
 
 	void Manager::spawn_worker( unsigned int worker_id ) throw( ManagerException ) {
 
-		Logger &logger = Logger::instance();
 		pid_t worker_pid;
 
 		// create a worker child
@@ -122,7 +119,7 @@ namespace bitz {
 			_manager.worker_pool[worker_id].worker_pid = worker_pid;
 
 			_manager.worker_pool[worker_id].worker->run( _manager.socket, _manager.max_worker_requests, _manager.comm_timeout );
-			logger.info( std::string( "end of cycle, worker[" ).append( util::itoa( worker_id ) ).append( "]" ) );
+			_logger->info( std::string( "end of cycle, worker[" ).append( util::itoa( worker_id ) ).append( "]" ) );
 
 			delete _manager.worker_pool[worker_id].worker;
 			_exit( EXIT_SUCCESS );
@@ -130,7 +127,7 @@ namespace bitz {
 		} else {
 
 			/* manager */
-			logger.info( std::string( "[manager] worker spawned with pid: " ).append( util::itoa( worker_pid) ) );
+			_logger->info( std::string( "[manager] worker spawned with pid: " ).append( util::itoa( worker_pid) ) );
 
 			_manager.workers_count++;
 
@@ -146,12 +143,9 @@ namespace bitz {
 
 	void Manager::shutdown( bool graceful ) throw() {
 
-		// logger
-		Logger &logger = Logger::instance();
-
 		if ( _manager.worker ) {
 
-			logger.info( "[worker] manager shutdown request received" );
+			_logger->info( "[worker] manager shutdown request received" );
 
 			/* worker: cleanup */
 			delete _manager.worker_pool[_manager.worker_id].worker;
@@ -159,21 +153,21 @@ namespace bitz {
 		} else {
 
 			/* manager: stop all child processes */
-			logger.info( "[manager] shutdown request received" );
+			_logger->info( "[manager] shutdown request received" );
 
 			for (unsigned int i = 0; i < _manager.max_workers; i++ ) {
 				if ( _manager.worker_pool[i].worker_pid != 0 ) {
 					if ( graceful ) {
 						kill( _manager.worker_pool[i].worker_pid, SIGTERM );
-						logger.debug( std::string( "[manager] sending SIGTERM to worker[" ).append( util::itoa( i ) )
+						_logger->debug( std::string( "[manager] sending SIGTERM to worker[" ).append( util::itoa( i ) )
 								.append( "], pid: " ).append( util::itoa( _manager.worker_pool[i].worker_pid ) ) );
 					} else {
 						kill( _manager.worker_pool[i].worker_pid, SIGKILL );
-						logger.debug( std::string( "[manager] sending SIGKILL to worker[" ).append( util::itoa( i ) )
+						_logger->debug( std::string( "[manager] sending SIGKILL to worker[" ).append( util::itoa( i ) )
 								.append( "], pid: " ).append( util::itoa( _manager.worker_pool[i].worker_pid ) ) );
 					}
 				} else {
-					logger.debug( std::string( "[manager] worker[" ).append( util::itoa( i ) ).append( "] already closed" ) );
+					_logger->debug( std::string( "[manager] worker[" ).append( util::itoa( i ) ).append( "] already closed" ) );
 				}
 			}
 		}
@@ -183,9 +177,7 @@ namespace bitz {
 
 	void Manager::reap_worker( pid_t worker_pid ) throw() {
 
-		// logger
-		Logger &logger = Logger::instance();
-		logger.debug( std::string( "reaping worker, pid: " ).append( util::itoa( worker_pid ) ) );
+		_logger->debug( std::string( "reaping worker, pid: " ).append( util::itoa( worker_pid ) ) );
 
 		if (! _manager.worker ) {
 			for (unsigned int i = 0; i < _manager.max_workers; i++ ) {
@@ -205,10 +197,7 @@ namespace bitz {
 	}
 
 
-	void Manager::manager_workers() throw() {
-
-		// logger
-		Logger &logger = Logger::instance();
+	void Manager::manage_workers() throw() {
 
 		if (! _manager.worker ) {
 
@@ -222,7 +211,7 @@ namespace bitz {
 							// spawn a worker for the missing
 							spawn_worker( i );
 						} catch ( ManagerException &mex ) {
-							logger.warn( std::string( "[manager] failed to spawn worker[" ).append( util::itoa( i ) ).append( "], exception: ").append( mex.what() ) );
+							_logger->warn( std::string( "[manager] failed to spawn worker[" ).append( util::itoa( i ) ).append( "], exception: ").append( mex.what() ) );
 						}
 					}
 				}
diff --git a/src/bitz/manager.h b/src/bitz/manager.h
index ce49e9e..8ad23e9 100644
--- a/src/bitz/manager.h
+++ b/src/bitz/manager.h
@@ -21,6 +21,7 @@
 #define BITZ_MANAGER_H
 
 #include <unistd.h>
+#include <spdlog/spdlog.h>
 #include <psocksxx/tcpnsockstream.h>
 
 #include "manager_exception.h"
@@ -75,11 +76,12 @@ namespace bitz {
 
 		virtual void shutdown( bool graceful = true ) throw();
 		virtual void reap_worker( pid_t worker_pid ) throw();
-		virtual void manager_workers() throw();
+		virtual void manage_workers() throw();
 
 
 	private:
-		manager_t         _manager;
+		manager_t _manager;
+		std::shared_ptr<spdlog::logger> _logger;
 
 		virtual void spawn_worker( unsigned int worker_id ) throw( ManagerException );
 
diff --git a/src/bitz/request_handler.cpp b/src/bitz/request_handler.cpp
index 56f9bc0..aa906f9 100644
--- a/src/bitz/request_handler.cpp
+++ b/src/bitz/request_handler.cpp
@@ -19,7 +19,6 @@
 
 #include "request_handler.h"
 #include "config.h"
-#include "logger.h"
 #include "util.h"
 
 #include <dlfcn.h>
@@ -37,6 +36,9 @@ namespace bitz {
 		// update variables
 		_req_handler.method = method;
 
+		// logger
+		_logger = spdlog::get( "bitz-server" );
+
 		// load modifier modules
 		load_modules();
 
@@ -52,8 +54,7 @@ namespace bitz {
 			delete [] _handlers;
 		}
 
-		Logger &logger = Logger::instance();
-		logger.debug( std::string( "[req] exiting request handler [" ).append( _req_handler.method ).append( "]" ) );
+		_logger->debug( std::string( "[req] exiting request handler [" ).append( _req_handler.method ).append( "]" ) );
 
 	}
 
@@ -65,13 +66,9 @@ namespace bitz {
 
 	icap::Response * RequestHandler::process( icap::RequestHeader * req_header, psocksxx::iosockstream * socket ) throw() {
 
-
 		icap::Request  * request;
 		icap::Response * response = NULL;
 
-		// logger
-		Logger &logger = Logger::instance();
-
 
 		// request
 		request = new icap::Request( req_header );
@@ -79,22 +76,22 @@ namespace bitz {
 		// read request data
 		if (! icap::util::read_req_data( request, socket ) ) {
 
-			logger.warn( "[req] failed to read request data" );
+			_logger->warn( "[req] failed to read request data" );
 			response = new icap::Response( icap::ResponseHeader::SERVER_ERROR );
 
 		} else {
 
-			logger.debug( std::string( "[req] payload.req-hdr:\r\n").append( request->payload().req_header ) );
-			logger.debug( std::string( "[req] payload.req-body:\r\n").append( request->payload().req_body ) );
-			logger.debug( std::string( "[req] payload.res-hdr:\r\n").append( request->payload().res_header ) );
-			logger.debug( std::string( "[req] payload.res-body:\r\n").append( request->payload().res_body ) );
+			_logger->debug( std::string( "[req] payload.req-hdr:\r\n").append( request->payload().req_header ) );
+			_logger->debug( std::string( "[req] payload.req-body:\r\n").append( request->payload().req_body ) );
+			_logger->debug( std::string( "[req] payload.res-hdr:\r\n").append( request->payload().res_header ) );
+			_logger->debug( std::string( "[req] payload.res-body:\r\n").append( request->payload().res_body ) );
 
 
 			// check for message preview
 			if ( request->preview_size() >= 0 ) {
 
 				// process preview
-				logger.debug( std::string( "[req] message preview request, preview: " ).append( util::itoa( request->preview_size() ) ) );
+				_logger->debug( std::string( "[req] message preview request, preview: " ).append( util::itoa( request->preview_size() ) ) );
 				response = process_preview( request, socket );
 
 			}
@@ -108,7 +105,7 @@ namespace bitz {
 			if ( response == NULL ) {
 
 				// process modify
-				logger.debug( "[req] modify request" );
+				_logger->debug( "[req] modify request" );
 				response = process_modify( request );
 
 			}
@@ -120,7 +117,7 @@ namespace bitz {
 
 		// sanity check
 		if ( response == NULL ) {
-			logger.warn( "[req] no valid response from modifiers, creating a server error (500) response" );
+			_logger->warn( "[req] no valid response from modifiers, creating a server error (500) response" );
 			response = new icap::Response( icap::ResponseHeader::SERVER_ERROR );
 		}
 
@@ -131,18 +128,15 @@ namespace bitz {
 
 	bool RequestHandler::load_modifier( const std::string &file, Modifier::symbols_t &symbols ) throw() {
 
-		// logger
-		Logger &logger = Logger::instance();
-
 		// vars
 		const char* dlsym_error;
 
 		// load the modifier module
-		logger.debug( "[req] loading modifier: " + file );
+		_logger->debug( "[req] loading modifier: " + file );
 		symbols.modifier = dlopen( file.c_str(), RTLD_LAZY | RTLD_LOCAL );
 
 		if (! symbols.modifier ) {
-			logger.warn( std::string( "[req] failed to load modifier: " ).append( file ).append( dlerror() ) );
+			_logger->warn( std::string( "[req] failed to load modifier: " ).append( file ).append( dlerror() ) );
 			return false;
 		}
 
@@ -154,7 +148,7 @@ namespace bitz {
 		dlsym_error    = dlerror();
 
 		if ( dlsym_error ) {
-			logger.warn( std::string( "[req] failed to load create symbol: " ).append( dlsym_error ) );
+			_logger->warn( std::string( "[req] failed to load create symbol: " ).append( dlsym_error ) );
 			return false;
 		}
 
@@ -162,7 +156,7 @@ namespace bitz {
 		dlsym_error     = dlerror();
 
 		if ( dlsym_error ) {
-			logger.warn( std::string( "[req] failed to load destroy symbol: " ).append( dlsym_error ) );
+			_logger->warn( std::string( "[req] failed to load destroy symbol: " ).append( dlsym_error ) );
 			return false;
 		}
 
@@ -223,12 +217,9 @@ namespace bitz {
 
 		int i = 0;
 
-		// logger
-		Logger &logger = Logger::instance();
-
 		for ( i = 0; i < _handlers_count; i++ ) {
 
-			logger.debug( std::string( "[req] unloading module: " ).append( _handlers[i].name ) );
+			_logger->debug( std::string( "[req] unloading module: " ).append( _handlers[i].name ) );
 
 			// unload
 			unload_modifier( _handlers[i].symbols.modifier );
@@ -246,9 +237,6 @@ namespace bitz {
 		int i = 0;
 		bool continue_status = false;
 
-		// logger
-		Logger &logger = Logger::instance();
-
 
 		/*
 		*  Loop through loaded modifier modules and grab responses
@@ -262,17 +250,17 @@ namespace bitz {
 
 			// sanity check
 			if ( _handlers[i].name == "" ) {
-				logger.info( "[req] modifier not loaded, not trying to get a response" );
+				_logger->info( "[req] modifier not loaded, not trying to get a response" );
 				continue;
 			}
 
 			// grab the response from modifier
-			logger.debug( std::string( "[req] getting preview response from modifier: " ).append( _handlers[i].name ) );
+			_logger->debug( std::string( "[req] getting preview response from modifier: " ).append( _handlers[i].name ) );
 			modifier = _handlers[i].symbols.create();
 			response = modifier->preview( request );
 
 			// cleanup
-			logger.debug( std::string( "[req] cleaning up modifier: " ).append( _handlers[i].name ) );
+			_logger->debug( std::string( "[req] cleaning up modifier: " ).append( _handlers[i].name ) );
 			_handlers[i].symbols.destroy( modifier );
 
 			// check response status
@@ -309,7 +297,7 @@ namespace bitz {
 			}
 
 			// we shouldn't have got this far
-			logger.info( std::string( "[req] unrecognised preview response from modifier: " ).append( _handlers[i].name ) );
+			_logger->info( std::string( "[req] unrecognised preview response from modifier: " ).append( _handlers[i].name ) );
 
 		}
 
@@ -325,9 +313,6 @@ namespace bitz {
 
 		int i = 0;
 
-		// logger
-		Logger &logger = Logger::instance();
-
 
 		/*
 		*  Loop through loaded modifier modules and grab responses
@@ -339,22 +324,22 @@ namespace bitz {
 
 			// sanity check
 			if ( _handlers[i].name == "" ) {
-				logger.info( "[req] modifier not loaded, not trying to get a response" );
+				_logger->info( "[req] modifier not loaded, not trying to get a response" );
 				continue;
 			}
 
 			// grab the response from modifier
-			logger.debug( std::string( "[req] getting modify response from modifier: " ).append( _handlers[i].name ) );
+			_logger->debug( std::string( "[req] getting modify response from modifier: " ).append( _handlers[i].name ) );
 			modifier = _handlers[i].symbols.create();
 			response = modifier->modify( request );
 
 			// cleanup
-			logger.debug( std::string( "[req] cleaning up modifier: " ).append( _handlers[i].name ) );
+			_logger->debug( std::string( "[req] cleaning up modifier: " ).append( _handlers[i].name ) );
 			_handlers[i].symbols.destroy( modifier );
 
 			// status 200 OK means content modified
 			if ( response->header()->status() == icap::ResponseHeader::OK ) {
-				logger.debug( "[req] OK response received, not getting responses from other modifiers" );
+				_logger->debug( "[req] OK response received, not getting responses from other modifiers" );
 				break;
 			}
 
@@ -369,15 +354,11 @@ namespace bitz {
 
 		bool status = false;
 
-		// logger
-		Logger &logger = Logger::instance();
-
-
 		// sanity check
 		if ( request->payload().ieof ) {
 
 			// we can process a '100 Continue' only if an 'ieof' is not received
-			logger.warn( "[req] illegal '100 Continue' response" );
+			_logger->warn( "[req] illegal '100 Continue' response" );
 
 		} else {
 
diff --git a/src/bitz/request_handler.h b/src/bitz/request_handler.h
index 2c31090..e05832c 100644
--- a/src/bitz/request_handler.h
+++ b/src/bitz/request_handler.h
@@ -25,6 +25,7 @@
 #include <icap/response.h>
 #include <icap/request.h>
 #include <psocksxx/iosockstream.h>
+#include <spdlog/spdlog.h>
 
 
 namespace bitz {
@@ -124,6 +125,7 @@ namespace bitz {
 	private:
 
 		req_handler_t _req_handler;
+		std::shared_ptr<spdlog::logger> _logger;
 
 	};
 
diff --git a/src/bitz/worker.cpp b/src/bitz/worker.cpp
index 42fb3d0..202f531 100644
--- a/src/bitz/worker.cpp
+++ b/src/bitz/worker.cpp
@@ -18,7 +18,6 @@
  */
 
 #include "worker.h"
-#include "logger.h"
 #include "util.h"
 #include "options_request_handler.h"
 #include "reqmod_request_handler.h"
@@ -32,6 +31,9 @@ namespace bitz {
 
 	Worker::Worker() {
 
+		// logger
+		_logger = spdlog::get( "bitz-server" );
+
 		// load request handlers
 		load_req_handlers();
 
@@ -40,9 +42,7 @@ namespace bitz {
 
 	Worker::~Worker() {
 
-		// logger
-		Logger &logger = Logger::instance();
-		logger.debug( "[worker] exiting" );
+		_logger->debug( "[worker] exiting" );
 
 		// cleanup request handlers
 		util::delete_req_handlers( _req_handlers );
@@ -54,15 +54,12 @@ namespace bitz {
 	void Worker::run( psocksxx::tcpnsockstream * server_sock, unsigned int max_requests,
 			unsigned int comm_timeout ) throw() {
 
-		// logger
-		Logger &logger = Logger::instance();
-
 		// client socket stream
 		psocksxx::nsockstream * client_sock;
 
 		while ( max_requests > 0 ) {
 
-			logger.debug( std::string( "[worker] waiting for a connection" ) );
+			_logger->debug( std::string( "[worker] waiting for a connection" ) );
 
 			try {
 
@@ -70,7 +67,7 @@ namespace bitz {
 				client_sock = server_sock->accept();
 
 				// FIXME: log accepted client details (e.g. address, port etc.)
-				logger.debug( std::string( "[worker] new connection accepted on [...]" ) );
+				_logger->debug( std::string( "[worker] new connection accepted on [...]" ) );
 
 				// set timeout value
 				if ( comm_timeout > 0 ) {
@@ -81,7 +78,7 @@ namespace bitz {
 			} catch ( psocksxx::sockexception &e ) {
 
 				// failed to accept client connection
-				logger.error( std::string( "[worker] failed to accept connection: " ).append( e.what() ) );
+				_logger->error( std::string( "[worker] failed to accept connection: " ).append( e.what() ) );
 
 				// update request count
 				max_requests--;
@@ -123,9 +120,6 @@ namespace bitz {
 
 	unsigned int Worker::serve_client( psocksxx::nsockstream * client_sock, unsigned int max_requests ) throw() {
 
-		// logger
-		Logger &logger = Logger::instance();
-
 		icap::RequestHeader * req_header = NULL;
 		icap::Response * response;
 		RequestHandler * req_handler;
@@ -140,11 +134,11 @@ namespace bitz {
 
 			// request header
 			req_header  = icap::util::read_req_header( client_sock );
-			logger.debug( std::string( "[worker] request header:\r\n" ).append( req_header->raw_data() ) );
+			_logger->debug( std::string( "[worker] request header:\r\n" ).append( req_header->raw_data() ) );
 
 			// check timeout
 			if ( client_sock->timedout() ) {
-				logger.warn( "[worker] communication timed out..." );
+				_logger->warn( "[worker] communication timed out..." );
 				return --max_requests;
 			}
 
@@ -154,7 +148,7 @@ namespace bitz {
 			// sanity check
 			if ( req_handler != NULL ) {
 
-				logger.debug( std::string( "[worker] handling request: " ).append( req_header->method() ) );
+				_logger->debug( std::string( "[worker] handling request: " ).append( req_header->method() ) );
 
 				// process the request and grab the response
 				response = req_handler->process( req_header, client_sock );
@@ -162,7 +156,7 @@ namespace bitz {
 			} else {
 
 				// unsupported request
-				logger.info( std::string( "[worker] unsupported request: " ).append( req_header->method() ) );
+				_logger->info( std::string( "[worker] unsupported request: " ).append( req_header->method() ) );
 				response = new icap::Response( new icap::ResponseHeader( icap::ResponseHeader::NOT_ALLOWED ) );
 
 			}
diff --git a/src/bitz/worker.h b/src/bitz/worker.h
index 25b7bac..a3c3951 100644
--- a/src/bitz/worker.h
+++ b/src/bitz/worker.h
@@ -20,6 +20,7 @@
 #ifndef BITZ_WORKER_H
 #define BITZ_WORKER_H
 
+#include <spdlog/spdlog.h>
 #include <psocksxx/tcpnsockstream.h>
 
 #include "common.h"
@@ -36,7 +37,8 @@ namespace bitz {
 				unsigned int max_requests, unsigned int comm_timeout = 0 ) throw();
 
 	private:
-		req_handlers_t    _req_handlers;
+		req_handlers_t _req_handlers;
+		std::shared_ptr<spdlog::logger> _logger;
 
 		virtual void load_req_handlers() throw();
 		virtual unsigned int serve_client( psocksxx::nsockstream * client_sock, unsigned int max_requests ) throw();
diff --git a/src/main.cpp b/src/main.cpp
index 7570e3a..c65ccc4 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -22,8 +22,8 @@
 #include <config.h>
 #include "bitz-server.h"
 #include "bitz/config.h"
-#include "bitz/logger.h"
 #include "bitz/util.h"
+#include "spdlog/spdlog.h"
 
 
 int main( int argc, char **argv ) {
@@ -34,6 +34,12 @@ int main( int argc, char **argv ) {
 	// read command line options
 	bitz::server::options_t opt = bitz::server::read_options( argc, argv );
 
+	// logger
+	auto logger = spdlog::stdout_color_st( "bitz-server" );
+	if ( opt.debug_flag == 1 ) {
+		spdlog::set_level( spdlog::level::debug );
+	}
+
 	// initialise configurations
 	bitz::Config &server_config = bitz::Config::instance();
 
@@ -48,28 +54,39 @@ int main( int argc, char **argv ) {
 
 	// create directories
 	if ( ( opt.debug_flag != 1 ) && (! bitz::util::mkdirp( bitz::util::dirpath( config.pid_file ) ) ) ) {
-		std::cerr << "[core] failed to create run dir" << std::endl;
+		logger->critical( "[core] failed to create run dir" );
 		exit( EXIT_FAILURE );
 	}
 
 	if (! bitz::util::mkdirp( bitz::util::dirpath( config.log_file ) ) ) {
-		std::cerr << "[core] failed to create log dir" << std::endl;
+		logger->critical( "[core] failed to create log dir" );
 		exit( EXIT_FAILURE );
 	}
 
 
 	// daemonize
 	if ( opt.debug_flag != 1 ) {
+
+		// close stdout logger
+		spdlog::drop( "bitz-server" );
+
+		// daemonize
 		bitz::server::daemonize( bitz::util::dirpath( config.pid_file ).c_str(), config.pid_file.c_str() );
+
+		// open a file logger
+		logger = spdlog::rotating_logger_mt( "bitz-server", config.log_file, ( 1048576 * 1024 ), 7 );
+
+	} else {
+		logger->info( "{} initialised", PACKAGE_STRING );
 	}
 
-	// initialise the logger
-	bitz::Logger &logger = bitz::Logger::instance( config.log_file, config.log_category );
-	logger.info( std::string( PACKAGE_STRING ) + " initialised" );
 
 	// start the server
 	bitz::server::start( config.port, config.max_workers, config.max_worker_requests, config.comm_timeout );
 
+	// flush logs
+	logger->flush();
+
 	// run the server
 	bitz::server::run();