1 /* sane - Scanner Access Now Easy. 2 3 Copyright (C) 2019 Povilas Kanapickas <povilas@radix.lt> 4 5 This file is part of the SANE package. 6 7 This program is free software; you can redistribute it and/or 8 modify it under the terms of the GNU General Public License as 9 published by the Free Software Foundation; either version 2 of the 10 License, or (at your option) any later version. 11 12 This program is distributed in the hope that it will be useful, but 13 WITHOUT ANY WARRANTY; without even the implied warranty of 14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 15 General Public License for more details. 16 17 You should have received a copy of the GNU General Public License 18 along with this program. If not, see <https://www.gnu.org/licenses/>. 19 20 As a special exception, the authors of SANE give permission for 21 additional uses of the libraries contained in this release of SANE. 22 23 The exception is that, if you link a SANE library with other files 24 to produce an executable, this does not by itself cause the 25 resulting executable to be covered by the GNU General Public 26 License. Your use of that executable is in no way restricted on 27 account of linking the SANE library code into it. 28 29 This exception does not, however, invalidate any other reasons why 30 the executable file might be covered by the GNU General Public 31 License. 32 33 If you submit changes to SANE to the maintainers to be included in 34 a subsequent release, you agree by submitting the changes that 35 those changes may be distributed with this exception intact. 36 37 If you write modifications of your own for SANE, it is your choice 38 whether to permit this exception to apply to your modifications. 39 If you do not wish that, delete this exception notice. 40 */ 41 42 #ifndef BACKEND_GENESYS_IMAGE_BUFFER_H 43 #define BACKEND_GENESYS_IMAGE_BUFFER_H 44 45 #include "enums.h" 46 #include "row_buffer.h" 47 #include <algorithm> 48 #include <functional> 49 50 namespace genesys { 51 52 // This class allows reading from row-based source in smaller or larger chunks of data 53 class ImageBuffer 54 { 55 public: 56 using ProducerCallback = std::function<bool(std::size_t size, std::uint8_t* out_data)>; 57 static constexpr std::uint64_t BUFFER_SIZE_UNSET = std::numeric_limits<std::uint64_t>::max(); 58 ImageBuffer()59 ImageBuffer() {} 60 ImageBuffer(std::size_t size, ProducerCallback producer); 61 available()62 std::size_t available() const { return curr_size_ - buffer_offset_; } 63 64 // allows adjusting the amount of data left so that we don't do a full size read from the 65 // producer on the last iteration. Set to BUFFER_SIZE_UNSET to ignore buffer size. remaining_size()66 std::uint64_t remaining_size() const { return remaining_size_; } set_remaining_size(std::uint64_t bytes)67 void set_remaining_size(std::uint64_t bytes) { remaining_size_ = bytes; } 68 69 // May be used to force the last read to be rounded up of a certain number of bytes set_last_read_multiple(std::uint64_t bytes)70 void set_last_read_multiple(std::uint64_t bytes) { last_read_multiple_ = bytes; } 71 72 bool get_data(std::size_t size, std::uint8_t* out_data); 73 74 private: 75 ProducerCallback producer_; 76 std::size_t size_ = 0; 77 std::size_t curr_size_ = 0; 78 79 std::uint64_t remaining_size_ = BUFFER_SIZE_UNSET; 80 std::uint64_t last_read_multiple_ = BUFFER_SIZE_UNSET; 81 82 std::size_t buffer_offset_ = 0; 83 std::vector<std::uint8_t> buffer_; 84 }; 85 86 } // namespace genesys 87 88 #endif // BACKEND_GENESYS_IMAGE_BUFFER_H 89