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Diffstat (limited to 'backend/genesys/image_buffer.cpp')
| -rw-r--r-- | backend/genesys/image_buffer.cpp | 203 |
1 files changed, 203 insertions, 0 deletions
diff --git a/backend/genesys/image_buffer.cpp b/backend/genesys/image_buffer.cpp new file mode 100644 index 0000000..07c6987 --- /dev/null +++ b/backend/genesys/image_buffer.cpp @@ -0,0 +1,203 @@ +/* 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. +*/ + +#define DEBUG_DECLARE_ONLY + +#include "image_buffer.h" +#include "image.h" + +namespace genesys { + +ImageBuffer::ImageBuffer(std::size_t size, ProducerCallback producer) : + producer_{producer}, + size_{size}, + buffer_offset_{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; + got_data &= producer_(size_, buffer_.data()); + + copy_buffer(); + } while(out_data < out_data_end && got_data); + + return got_data; +} + +void FakeBufferModel::push_step(std::size_t buffer_size, std::size_t row_bytes) +{ + sizes_.push_back(buffer_size); + available_sizes_.push_back(0); + row_bytes_.push_back(row_bytes); +} + +std::size_t FakeBufferModel::available_space() const +{ + if (sizes_.empty()) + throw SaneException("Model has not been setup"); + return sizes_.front() - available_sizes_.front(); +} + +void FakeBufferModel::simulate_read(std::size_t size) +{ + if (sizes_.empty()) { + throw SaneException("Model has not been setup"); + } + if (available_space() < size) { + throw SaneException("Attempted to simulate read of too much memory"); + } + + available_sizes_.front() += size; + + for (unsigned i = 1; i < sizes_.size(); ++i) { + auto avail_src = available_sizes_[i - 1]; + auto avail_dst = sizes_[i] - available_sizes_[i]; + + auto avail = (std::min(avail_src, avail_dst) / row_bytes_[i]) * row_bytes_[i]; + available_sizes_[i - 1] -= avail; + available_sizes_[i] += avail; + } + available_sizes_.back() = 0; +} + +ImageBufferGenesysUsb::ImageBufferGenesysUsb(std::size_t total_size, + const FakeBufferModel& buffer_model, + ProducerCallback producer) : + remaining_size_{total_size}, + buffer_model_{buffer_model}, + producer_{producer} +{} + +bool ImageBufferGenesysUsb::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 + do { + if (remaining_size_ == 0) + return false; + + auto bytes_to_read = get_read_size(); + buffer_offset_ = 0; + buffer_end_ = bytes_to_read; + buffer_.resize(bytes_to_read); + + producer_(bytes_to_read, buffer_.data()); + + if (remaining_size_ < bytes_to_read) { + remaining_size_ = 0; + } else { + remaining_size_ -= bytes_to_read; + } + + copy_buffer(); + } while(out_data < out_data_end); + return true; +} + +std::size_t ImageBufferGenesysUsb::get_read_size() +{ + std::size_t size = buffer_model_.available_space(); + + // never read an odd number. exception: last read + // the chip internal counter does not count half words. + size &= ~1; + + // Some setups need the reads to be multiples of 256 bytes + size &= ~0xff; + + if (remaining_size_ < size) { + size = remaining_size_; + /*round up to a multiple of 256 bytes */ + size += (size & 0xff) ? 0x100 : 0x00; + size &= ~0xff; + } + + buffer_model_.simulate_read(size); + + return size; +} + +} // namespace genesys |