kopia lustrzana https://gitlab.com/sane-project/backends
89 wiersze
3.3 KiB
C++
89 wiersze
3.3 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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As a special exception, the authors of SANE give permission for
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additional uses of the libraries contained in this release of SANE.
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The exception is that, if you link a SANE library with other files
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to produce an executable, this does not by itself cause the
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resulting executable to be covered by the GNU General Public
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License. Your use of that executable is in no way restricted on
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account of linking the SANE library code into it.
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This exception does not, however, invalidate any other reasons why
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the executable file might be covered by the GNU General Public
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License.
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If you submit changes to SANE to the maintainers to be included in
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a subsequent release, you agree by submitting the changes that
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those changes may be distributed with this exception intact.
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If you write modifications of your own for SANE, it is your choice
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whether to permit this exception to apply to your modifications.
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If you do not wish that, delete this exception notice.
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*/
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#ifndef BACKEND_GENESYS_IMAGE_BUFFER_H
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#define BACKEND_GENESYS_IMAGE_BUFFER_H
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#include "enums.h"
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#include "row_buffer.h"
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#include <algorithm>
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#include <functional>
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namespace genesys {
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// This class allows reading from row-based source in smaller or larger chunks of data
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class ImageBuffer
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{
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public:
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using ProducerCallback = std::function<bool(std::size_t size, std::uint8_t* out_data)>;
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static constexpr std::uint64_t BUFFER_SIZE_UNSET = std::numeric_limits<std::uint64_t>::max();
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ImageBuffer() {}
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ImageBuffer(std::size_t size, ProducerCallback producer);
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std::size_t available() const { return curr_size_ - buffer_offset_; }
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// allows adjusting the amount of data left so that we don't do a full size read from the
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// producer on the last iteration. Set to BUFFER_SIZE_UNSET to ignore buffer size.
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std::uint64_t remaining_size() const { return remaining_size_; }
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void set_remaining_size(std::uint64_t bytes) { remaining_size_ = bytes; }
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// May be used to force the last read to be rounded up of a certain number of bytes
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void set_last_read_multiple(std::uint64_t bytes) { last_read_multiple_ = bytes; }
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bool get_data(std::size_t size, std::uint8_t* out_data);
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private:
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ProducerCallback producer_;
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std::size_t size_ = 0;
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std::size_t curr_size_ = 0;
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std::uint64_t remaining_size_ = BUFFER_SIZE_UNSET;
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std::uint64_t last_read_multiple_ = BUFFER_SIZE_UNSET;
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std::size_t buffer_offset_ = 0;
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std::vector<std::uint8_t> buffer_;
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};
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} // namespace genesys
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#endif // BACKEND_GENESYS_IMAGE_BUFFER_H
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