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
21#define DEBUG_DECLARE_ONLY
22
23#include "image_buffer.h"
24#include "image.h"
25#include "utilities.h"
26
27namespace genesys {
28
29ImageBuffer::ImageBuffer(std::size_t size, ProducerCallback producer) :
30    producer_{producer},
31    size_{size}
32{
33    buffer_.resize(size_);
34}
35
36bool ImageBuffer::get_data(std::size_t size, std::uint8_t* out_data)
37{
38    const std::uint8_t* out_data_end = out_data + size;
39
40    auto copy_buffer = [&]()
41    {
42        std::size_t bytes_copy = std::min<std::size_t>(out_data_end - out_data, available());
43        std::memcpy(out_data, buffer_.data() + buffer_offset_, bytes_copy);
44        out_data += bytes_copy;
45        buffer_offset_ += bytes_copy;
46    };
47
48    // first, read remaining data from buffer
49    if (available() > 0) {
50        copy_buffer();
51    }
52
53    if (out_data == out_data_end) {
54        return true;
55    }
56
57    // now the buffer is empty and there's more data to be read
58    bool got_data = true;
59    do {
60        buffer_offset_ = 0;
61
62        std::size_t size_to_read = size_;
63        if (remaining_size_ != BUFFER_SIZE_UNSET) {
64            size_to_read = std::min<std::uint64_t>(size_to_read, remaining_size_);
65            remaining_size_ -= size_to_read;
66        }
67
68        std::size_t aligned_size_to_read = size_to_read;
69        if (remaining_size_ == 0 && last_read_multiple_ != BUFFER_SIZE_UNSET) {
70            aligned_size_to_read = align_multiple_ceil(size_to_read, last_read_multiple_);
71        }
72
73        got_data &= producer_(aligned_size_to_read, buffer_.data());
74        curr_size_ = size_to_read;
75
76        copy_buffer();
77
78        if (remaining_size_ == 0 && out_data < out_data_end) {
79            got_data = false;
80        }
81
82    } while (out_data < out_data_end && got_data);
83
84    return got_data;
85}
86
87} // namespace genesys
88