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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/>.
*/
#define DEBUG_DECLARE_ONLY
#include "image_buffer.h"
#include "image.h"
#include "utilities.h"
namespace genesys {
ImageBuffer::ImageBuffer(std::size_t size, ProducerCallback producer) :
producer_{producer},
size_{size}
{
buffer_.resize(size_);
}
bool ImageBuffer::get_data(std::size_t size, std::uint8_t* out_data)
{
const std::uint8_t* out_data_end = out_data + size;
auto copy_buffer = [&]()
{
std::size_t bytes_copy = std::min<std::size_t>(out_data_end - out_data, available());
std::memcpy(out_data, buffer_.data() + buffer_offset_, bytes_copy);
out_data += bytes_copy;
buffer_offset_ += bytes_copy;
};
// first, read remaining data from buffer
if (available() > 0) {
copy_buffer();
}
if (out_data == out_data_end) {
return true;
}
// now the buffer is empty and there's more data to be read
bool got_data = true;
do {
buffer_offset_ = 0;
std::size_t size_to_read = size_;
if (remaining_size_ != BUFFER_SIZE_UNSET) {
size_to_read = std::min<std::uint64_t>(size_to_read, remaining_size_);
remaining_size_ -= size_to_read;
}
std::size_t aligned_size_to_read = size_to_read;
if (remaining_size_ == 0 && last_read_multiple_ != BUFFER_SIZE_UNSET) {
aligned_size_to_read = align_multiple_ceil(size_to_read, last_read_multiple_);
}
got_data &= producer_(aligned_size_to_read, buffer_.data());
curr_size_ = size_to_read;
copy_buffer();
if (remaining_size_ == 0 && out_data < out_data_end) {
got_data = false;
}
} while (out_data < out_data_end && got_data);
return got_data;
}
} // namespace genesys
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