diff options
Diffstat (limited to 'backend/genesys/row_buffer.h')
| -rw-r--r-- | backend/genesys/row_buffer.h | 214 |
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 index 0000000..e1a0c82 --- /dev/null +++ b/backend/genesys/row_buffer.h @@ -0,0 +1,214 @@ +/* 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 |