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 #define DEBUG_DECLARE_ONLY
43
44 #include "image_buffer.h"
45 #include "image.h"
46 #include "utilities.h"
47
48 namespace genesys {
49
ImageBuffer(std::size_t size,ProducerCallback producer)50 ImageBuffer::ImageBuffer(std::size_t size, ProducerCallback producer) :
51 producer_{producer},
52 size_{size}
53 {
54 buffer_.resize(size_);
55 }
56
get_data(std::size_t size,std::uint8_t * out_data)57 bool ImageBuffer::get_data(std::size_t size, std::uint8_t* out_data)
58 {
59 const std::uint8_t* out_data_end = out_data + size;
60
61 auto copy_buffer = [&]()
62 {
63 std::size_t bytes_copy = std::min<std::size_t>(out_data_end - out_data, available());
64 std::memcpy(out_data, buffer_.data() + buffer_offset_, bytes_copy);
65 out_data += bytes_copy;
66 buffer_offset_ += bytes_copy;
67 };
68
69 // first, read remaining data from buffer
70 if (available() > 0) {
71 copy_buffer();
72 }
73
74 if (out_data == out_data_end) {
75 return true;
76 }
77
78 // now the buffer is empty and there's more data to be read
79 bool got_data = true;
80 do {
81 buffer_offset_ = 0;
82
83 std::size_t size_to_read = size_;
84 if (remaining_size_ != BUFFER_SIZE_UNSET) {
85 size_to_read = std::min<std::uint64_t>(size_to_read, remaining_size_);
86 remaining_size_ -= size_to_read;
87 }
88
89 std::size_t aligned_size_to_read = size_to_read;
90 if (remaining_size_ == 0 && last_read_multiple_ != BUFFER_SIZE_UNSET) {
91 aligned_size_to_read = align_multiple_ceil(size_to_read, last_read_multiple_);
92 }
93
94 got_data &= producer_(aligned_size_to_read, buffer_.data());
95 curr_size_ = size_to_read;
96
97 copy_buffer();
98
99 if (remaining_size_ == 0 && out_data < out_data_end) {
100 got_data = false;
101 }
102
103 } while (out_data < out_data_end && got_data);
104
105 return got_data;
106 }
107
108 } // namespace genesys
109