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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, see <https://www.gnu.org/licenses/>.
*/
#ifndef BACKEND_GENESYS_IMAGE_BUFFER_H
#define BACKEND_GENESYS_IMAGE_BUFFER_H
#include "enums.h"
#include "row_buffer.h"
#include <algorithm>
#include <functional>
namespace genesys {
// This class allows reading from row-based source in smaller or larger chunks of data
class ImageBuffer
{
public:
using ProducerCallback = std::function<bool(std::size_t size, std::uint8_t* out_data)>;
static constexpr std::uint64_t BUFFER_SIZE_UNSET = std::numeric_limits<std::uint64_t>::max();
ImageBuffer() {}
ImageBuffer(std::size_t size, ProducerCallback producer);
std::size_t available() const { return curr_size_ - buffer_offset_; }
// allows adjusting the amount of data left so that we don't do a full size read from the
// producer on the last iteration. Set to BUFFER_SIZE_UNSET to ignore buffer size.
std::uint64_t remaining_size() const { return remaining_size_; }
void set_remaining_size(std::uint64_t bytes) { remaining_size_ = bytes; }
// May be used to force the last read to be rounded up of a certain number of bytes
void set_last_read_multiple(std::uint64_t bytes) { last_read_multiple_ = bytes; }
bool get_data(std::size_t size, std::uint8_t* out_data);
private:
ProducerCallback producer_;
std::size_t size_ = 0;
std::size_t curr_size_ = 0;
std::uint64_t remaining_size_ = BUFFER_SIZE_UNSET;
std::uint64_t last_read_multiple_ = BUFFER_SIZE_UNSET;
std::size_t buffer_offset_ = 0;
std::vector<std::uint8_t> buffer_;
};
} // namespace genesys
#endif // BACKEND_GENESYS_IMAGE_BUFFER_H
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