kopia lustrzana https://gitlab.com/sane-project/backends
88 wiersze
2.5 KiB
C++
88 wiersze
2.5 KiB
C++
/* sane - Scanner Access Now Easy.
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Copyright (C) 2019 Povilas Kanapickas <povilas@radix.lt>
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This file is part of the SANE package.
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This program is free software; you can redistribute it and/or
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modify it under the terms of the GNU General Public License as
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published by the Free Software Foundation; either version 2 of the
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License, or (at your option) any later version.
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This program is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <https://www.gnu.org/licenses/>.
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*/
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#define DEBUG_DECLARE_ONLY
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#include "image_buffer.h"
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#include "image.h"
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#include "utilities.h"
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namespace genesys {
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ImageBuffer::ImageBuffer(std::size_t size, ProducerCallback producer) :
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producer_{producer},
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size_{size}
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{
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buffer_.resize(size_);
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}
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bool ImageBuffer::get_data(std::size_t size, std::uint8_t* out_data)
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{
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const std::uint8_t* out_data_end = out_data + size;
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auto copy_buffer = [&]()
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{
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std::size_t bytes_copy = std::min<std::size_t>(out_data_end - out_data, available());
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std::memcpy(out_data, buffer_.data() + buffer_offset_, bytes_copy);
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out_data += bytes_copy;
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buffer_offset_ += bytes_copy;
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};
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// first, read remaining data from buffer
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if (available() > 0) {
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copy_buffer();
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}
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if (out_data == out_data_end) {
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return true;
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}
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// now the buffer is empty and there's more data to be read
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bool got_data = true;
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do {
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buffer_offset_ = 0;
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std::size_t size_to_read = size_;
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if (remaining_size_ != BUFFER_SIZE_UNSET) {
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size_to_read = std::min<std::uint64_t>(size_to_read, remaining_size_);
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remaining_size_ -= size_to_read;
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}
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std::size_t aligned_size_to_read = size_to_read;
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if (remaining_size_ == 0 && last_read_multiple_ != BUFFER_SIZE_UNSET) {
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aligned_size_to_read = align_multiple_ceil(size_to_read, last_read_multiple_);
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}
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got_data &= producer_(aligned_size_to_read, buffer_.data());
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curr_size_ = size_to_read;
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copy_buffer();
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if (remaining_size_ == 0 && out_data < out_data_end) {
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got_data = false;
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}
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} while (out_data < out_data_end && got_data);
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return got_data;
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}
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} // namespace genesys
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