Merge branch 'feature/upstream' into develop

1 files changed, 214 insertions, 0 deletions

diff --git a/backend/genesys/row_buffer.h b/backend/genesys/row_buffer.h
new file mode 100644
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+++ b/backend/genesys/row_buffer.h
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+/* sane - Scanner Access Now Easy.
+
+   Copyright (C) 2019 Povilas Kanapickas <povilas@radix.lt>
+
+   This file is part of the SANE package.
+
+   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 2 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.
+
+   As a special exception, the authors of SANE give permission for
+   additional uses of the libraries contained in this release of SANE.
+
+   The exception is that, if you link a SANE library with other files
+   to produce an executable, this does not by itself cause the
+   resulting executable to be covered by the GNU General Public
+   License.  Your use of that executable is in no way restricted on
+   account of linking the SANE library code into it.
+
+   This exception does not, however, invalidate any other reasons why
+   the executable file might be covered by the GNU General Public
+   License.
+
+   If you submit changes to SANE to the maintainers to be included in
+   a subsequent release, you agree by submitting the changes that
+   those changes may be distributed with this exception intact.
+
+   If you write modifications of your own for SANE, it is your choice
+   whether to permit this exception to apply to your modifications.
+   If you do not wish that, delete this exception notice.
+*/
+
+#ifndef BACKEND_GENESYS_LINE_BUFFER_H
+#define BACKEND_GENESYS_LINE_BUFFER_H
+
+#include "error.h"
+
+#include <algorithm>
+#include <cstdint>
+#include <cstddef>
+#include <vector>
+
+namespace genesys {
+
+class RowBuffer
+{
+public:
+    RowBuffer(std::size_t line_bytes) : row_bytes_{line_bytes} {}
+    RowBuffer(const RowBuffer&) = default;
+    RowBuffer& operator=(const RowBuffer&) = default;
+    ~RowBuffer() = default;
+
+    const std::uint8_t* get_row_ptr(std::size_t y) const
+    {
+        if (y >= height()) {
+            throw SaneException("y %zu is out of range", y);
+        }
+        return data_.data() + row_bytes_ * get_row_index(y);
+    }
+
+    std::uint8_t* get_row_ptr(std::size_t y)
+    {
+        if (y >= height()) {
+            throw SaneException("y %zu is out of range", y);
+        }
+        return data_.data() + row_bytes_ * get_row_index(y);
+    }
+
+    const std::uint8_t* get_front_row_ptr() const { return get_row_ptr(0); }
+    std::uint8_t* get_front_row_ptr() { return get_row_ptr(0); }
+    const std::uint8_t* get_back_row_ptr() const { return get_row_ptr(height() - 1); }
+    std::uint8_t* get_back_row_ptr() { return get_row_ptr(height() - 1); }
+
+    bool empty() const { return is_linear_ && first_ == last_; }
+
+    bool full()
+    {
+        if (is_linear_) {
+            return last_ == buffer_end_;
+        }
+        return first_ == last_;
+    }
+
+    bool is_linear() const { return is_linear_; }
+
+    void linearize()
+    {
+        if (!is_linear_) {
+            std::rotate(data_.begin(), data_.begin() + row_bytes_ * first_, data_.end());
+            last_ = height();
+            first_ = 0;
+            is_linear_ = true;
+        }
+    }
+
+    void pop_front()
+    {
+        if (empty()) {
+            throw SaneException("Trying to pop out of empty() line buffer");
+        }
+
+        first_++;
+        if (first_ == last_) {
+            first_ = 0;
+            last_ = 0;
+            is_linear_ = true;
+        } else  if (first_ == buffer_end_) {
+            first_ = 0;
+            is_linear_ = true;
+        }
+    }
+
+    void push_front()
+    {
+        if (height() + 1 >= height_capacity()) {
+            ensure_capacity(std::max<std::size_t>(1, height() * 2));
+        }
+
+        if (first_ == 0) {
+            is_linear_ = false;
+            first_ = buffer_end_;
+        }
+        first_--;
+    }
+
+    void pop_back()
+    {
+        if (empty()) {
+            throw SaneException("Trying to pop out of empty() line buffer");
+        }
+        if (last_ == 0) {
+            last_ = buffer_end_;
+            is_linear_ = true;
+        }
+        last_--;
+        if (first_ == last_) {
+            first_ = 0;
+            last_ = 0;
+            is_linear_ = true;
+        }
+    }
+
+    void push_back()
+    {
+        if (height() + 1 >= height_capacity()) {
+            ensure_capacity(std::max<std::size_t>(1, height() * 2));
+        }
+
+        if (last_ == buffer_end_) {
+            is_linear_ = false;
+            last_ = 0;
+        }
+        last_++;
+    }
+
+    std::size_t row_bytes() const { return row_bytes_; }
+
+    std::size_t height() const
+    {
+        if (!is_linear_) {
+            return last_ + buffer_end_ - first_;
+        }
+        return last_ - first_;
+    }
+
+    std::size_t height_capacity() const { return buffer_end_; }
+
+    void clear()
+    {
+        first_ = 0;
+        last_ = 0;
+    }
+
+private:
+    std::size_t get_row_index(std::size_t index) const
+    {
+        if (index >= buffer_end_ - first_) {
+            return index - (buffer_end_ - first_);
+        }
+        return index + first_;
+    }
+
+    void ensure_capacity(std::size_t capacity)
+    {
+        if (capacity < height_capacity())
+            return;
+        linearize();
+        data_.resize(capacity * row_bytes_);
+        buffer_end_ = capacity;
+    }
+
+private:
+    std::size_t row_bytes_ = 0;
+    std::size_t first_ = 0;
+    std::size_t last_ = 0;
+    std::size_t buffer_end_ = 0;
+    bool is_linear_ = true;
+    std::vector<std::uint8_t> data_;
+};
+
+} // namespace genesys
+
+#endif // BACKEND_GENESYS_LINE_BUFFER_H