From 8286ac511144e4f17d34eac9affb97e50646344a Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?J=C3=B6rg=20Frings-F=C3=BCrst?= Date: Wed, 23 Jul 2014 15:25:44 +0200 Subject: Imported Upstream version 4.0.0 --- .../boost/smart_ptr/detail/quick_allocator.hpp | 199 +++++++++++++++++++++ 1 file changed, 199 insertions(+) create mode 100644 libcutl/cutl/details/boost/smart_ptr/detail/quick_allocator.hpp (limited to 'libcutl/cutl/details/boost/smart_ptr/detail/quick_allocator.hpp') diff --git a/libcutl/cutl/details/boost/smart_ptr/detail/quick_allocator.hpp b/libcutl/cutl/details/boost/smart_ptr/detail/quick_allocator.hpp new file mode 100644 index 0000000..77e4731 --- /dev/null +++ b/libcutl/cutl/details/boost/smart_ptr/detail/quick_allocator.hpp @@ -0,0 +1,199 @@ +#ifndef BOOST_SMART_PTR_DETAIL_QUICK_ALLOCATOR_HPP_INCLUDED +#define BOOST_SMART_PTR_DETAIL_QUICK_ALLOCATOR_HPP_INCLUDED + +// MS compatible compilers support #pragma once + +#if defined(_MSC_VER) && (_MSC_VER >= 1020) +# pragma once +#endif + +// +// detail/quick_allocator.hpp +// +// Copyright (c) 2003 David Abrahams +// Copyright (c) 2003 Peter Dimov +// +// Distributed under the Boost Software License, Version 1.0. (See +// accompanying file LICENSE_1_0.txt or copy at +// http://www.boost.org/LICENSE_1_0.txt) +// + +#include + +#include +#include +#include + +#include // ::operator new, ::operator delete +#include // std::size_t + +namespace cutl_details_boost +{ + +namespace detail +{ + +template union freeblock +{ + typedef typename cutl_details_boost::type_with_alignment::type aligner_type; + aligner_type aligner; + char bytes[size]; + freeblock * next; +}; + +template struct allocator_impl +{ + typedef freeblock block; + + // It may seem odd to use such small pages. + // + // However, on a typical Windows implementation that uses + // the OS allocator, "normal size" pages interact with the + // "ordinary" operator new, slowing it down dramatically. + // + // 512 byte pages are handled by the small object allocator, + // and don't interfere with ::new. + // + // The other alternative is to use much bigger pages (1M.) + // + // It is surprisingly easy to hit pathological behavior by + // varying the page size. g++ 2.96 on Red Hat Linux 7.2, + // for example, passionately dislikes 496. 512 seems OK. + +#if defined(BOOST_QA_PAGE_SIZE) + + enum { items_per_page = BOOST_QA_PAGE_SIZE / size }; + +#else + + enum { items_per_page = 512 / size }; // 1048560 / size + +#endif + +#ifdef BOOST_HAS_THREADS + + static lightweight_mutex & mutex() + { + static freeblock< sizeof( lightweight_mutex ), cutl_details_boost::alignment_of< lightweight_mutex >::value > fbm; + static lightweight_mutex * pm = new( &fbm ) lightweight_mutex; + return *pm; + } + + static lightweight_mutex * mutex_init; + +#endif + + static block * free; + static block * page; + static unsigned last; + + static inline void * alloc() + { +#ifdef BOOST_HAS_THREADS + lightweight_mutex::scoped_lock lock( mutex() ); +#endif + if(block * x = free) + { + free = x->next; + return x; + } + else + { + if(last == items_per_page) + { + // "Listen to me carefully: there is no memory leak" + // -- Scott Meyers, Eff C++ 2nd Ed Item 10 + page = ::new block[items_per_page]; + last = 0; + } + + return &page[last++]; + } + } + + static inline void * alloc(std::size_t n) + { + if(n != size) // class-specific new called for a derived object + { + return ::operator new(n); + } + else + { +#ifdef BOOST_HAS_THREADS + lightweight_mutex::scoped_lock lock( mutex() ); +#endif + if(block * x = free) + { + free = x->next; + return x; + } + else + { + if(last == items_per_page) + { + page = ::new block[items_per_page]; + last = 0; + } + + return &page[last++]; + } + } + } + + static inline void dealloc(void * pv) + { + if(pv != 0) // 18.4.1.1/13 + { +#ifdef BOOST_HAS_THREADS + lightweight_mutex::scoped_lock lock( mutex() ); +#endif + block * pb = static_cast(pv); + pb->next = free; + free = pb; + } + } + + static inline void dealloc(void * pv, std::size_t n) + { + if(n != size) // class-specific delete called for a derived object + { + ::operator delete(pv); + } + else if(pv != 0) // 18.4.1.1/13 + { +#ifdef BOOST_HAS_THREADS + lightweight_mutex::scoped_lock lock( mutex() ); +#endif + block * pb = static_cast(pv); + pb->next = free; + free = pb; + } + } +}; + +#ifdef BOOST_HAS_THREADS + +template + lightweight_mutex * allocator_impl::mutex_init = &allocator_impl::mutex(); + +#endif + +template + freeblock * allocator_impl::free = 0; + +template + freeblock * allocator_impl::page = 0; + +template + unsigned allocator_impl::last = allocator_impl::items_per_page; + +template +struct quick_allocator: public allocator_impl< sizeof(T), cutl_details_boost::alignment_of::value > +{ +}; + +} // namespace detail + +} // namespace cutl_details_boost + +#endif // #ifndef BOOST_SMART_PTR_DETAIL_QUICK_ALLOCATOR_HPP_INCLUDED -- cgit v1.2.3