1/*
2Copyright 2018 Google Inc. All Rights Reserved.
3
4Licensed under the Apache License, Version 2.0 (the "License");
5you may not use this file except in compliance with the License.
6You may obtain a copy of the License at
7
8 http://www.apache.org/licenses/LICENSE-2.0
9
10Unless required by applicable law or agreed to in writing, software
11distributed under the License is distributed on an "AS-IS" BASIS,
12WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13See the License for the specific language governing permissions and
14limitations under the License.
15*/
16
17#include "dsp/circular_buffer.h"
18
19#include <algorithm>
20
21#include "base/constants_and_types.h"
22
23namespace vraudio {
24
25CircularBuffer::CircularBuffer(size_t buffer_length, size_t num_input_frames,
26 size_t num_output_frames)
27 : num_input_frames_(num_input_frames),
28 num_output_frames_(num_output_frames),
29 buffer_(kNumMonoChannels, buffer_length),
30 write_cursor_(0),
31 read_cursor_(0),
32 num_valid_frames_(0) {
33 CHECK_GE(buffer_length, num_input_frames + num_output_frames);
34}
35
36bool CircularBuffer::InsertBuffer(const AudioBuffer::Channel& input) {
37 DCHECK_EQ(input.size(), num_input_frames_);
38
39 if (num_valid_frames_ + num_input_frames_ > buffer_.num_frames()) {
40 return false;
41 }
42 // Remaining space after the write cursor.
43 const size_t forward_write_space = read_cursor_ <= write_cursor_
44 ? buffer_.num_frames() - write_cursor_
45 : read_cursor_ - write_cursor_;
46
47 // Copy the input into the buffer.
48 AudioBuffer::Channel* buffer_channel = &buffer_[0];
49 if (forward_write_space >= num_input_frames_) {
50 DCHECK_LE(buffer_channel->begin() + write_cursor_ + num_input_frames_,
51 buffer_channel->end());
52 std::copy(first: input.begin(), last: input.end(),
53 result: buffer_channel->begin() + write_cursor_);
54 } else {
55 DCHECK_LE(buffer_channel->begin() + write_cursor_ + forward_write_space,
56 buffer_channel->end());
57 DCHECK_LT(input.begin() + forward_write_space, input.end());
58 std::copy(first: input.begin(), last: input.begin() + forward_write_space,
59 result: buffer_channel->begin() + write_cursor_);
60 DCHECK_LE(buffer_channel->begin() + forward_write_space,
61 buffer_channel->end());
62 std::copy(first: input.begin() + forward_write_space, last: input.end(),
63 result: buffer_channel->begin());
64 }
65
66 write_cursor_ = (write_cursor_ + num_input_frames_) % buffer_.num_frames();
67 num_valid_frames_ += num_input_frames_;
68 return true;
69}
70
71bool CircularBuffer::RetrieveBuffer(AudioBuffer::Channel* output) {
72 return RetrieveBufferWithOffset(/*offset=*/0, output);
73}
74
75bool CircularBuffer::RetrieveBufferWithOffset(size_t offset,
76 AudioBuffer::Channel* output) {
77 DCHECK_LE(output->begin() + num_output_frames_ + offset, output->end());
78
79 if (num_valid_frames_ < num_output_frames_) {
80 return false;
81 }
82 // Remaining space after the read cursor.
83 const size_t forward_read_space = read_cursor_ < write_cursor_
84 ? write_cursor_ - read_cursor_
85 : buffer_.num_frames() - read_cursor_;
86
87 // Copy the buffer values into the output.
88 AudioBuffer::Channel* buffer_channel = &buffer_[0];
89 if (forward_read_space >= num_output_frames_) {
90 DCHECK_LE(buffer_channel->begin() + read_cursor_ + num_output_frames_,
91 buffer_channel->end());
92 std::copy(first: buffer_channel->begin() + read_cursor_,
93 last: buffer_channel->begin() + read_cursor_ + num_output_frames_,
94 result: output->begin() + offset);
95 } else {
96 DCHECK_LE(buffer_channel->begin() + read_cursor_ + forward_read_space,
97 buffer_channel->end());
98 DCHECK_LE(output->begin() + forward_read_space + offset, output->end());
99 std::copy(first: buffer_channel->begin() + read_cursor_,
100 last: buffer_channel->begin() + read_cursor_ + forward_read_space,
101 result: output->begin() + offset);
102 DCHECK_GE(buffer_channel->begin() + num_output_frames_ - forward_read_space,
103 buffer_channel->begin());
104 DCHECK_LE(output->begin() + offset + num_output_frames_, output->end());
105 std::copy(first: buffer_channel->begin(),
106 last: buffer_channel->begin() + num_output_frames_ - forward_read_space,
107 result: output->begin() + offset + forward_read_space);
108 }
109 read_cursor_ = (read_cursor_ + num_output_frames_) % buffer_.num_frames();
110 num_valid_frames_ -= num_output_frames_;
111 return true;
112}
113
114void CircularBuffer::Clear() {
115 read_cursor_ = 0;
116 write_cursor_ = 0;
117 num_valid_frames_ = 0;
118}
119
120} // namespace vraudio
121

source code of qtmultimedia/src/3rdparty/resonance-audio/resonance_audio/dsp/circular_buffer.cc