1 // Copyright 2014 The Chromium Authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style license that can be
3 // found in the LICENSE file.
4
5 #include <algorithm>
6
7 #include "media/base/audio_block_fifo.h"
8
9 #include "base/logging.h"
10
11 namespace media {
12
AudioBlockFifo(int channels,int frames,int blocks)13 AudioBlockFifo::AudioBlockFifo(int channels, int frames, int blocks)
14 : channels_(channels),
15 block_frames_(frames),
16 write_block_(0),
17 read_block_(0),
18 available_blocks_(0),
19 write_pos_(0) {
20 IncreaseCapacity(blocks);
21 }
22
~AudioBlockFifo()23 AudioBlockFifo::~AudioBlockFifo() {}
24
Push(const void * source,int frames,int bytes_per_sample)25 void AudioBlockFifo::Push(const void* source,
26 int frames,
27 int bytes_per_sample) {
28 DCHECK(source);
29 DCHECK_GT(frames, 0);
30 DCHECK_GT(bytes_per_sample, 0);
31 DCHECK_LT(available_blocks_, static_cast<int>(audio_blocks_.size()));
32 CHECK_LE(frames, GetUnfilledFrames());
33
34 const uint8* source_ptr = static_cast<const uint8*>(source);
35 int frames_to_push = frames;
36 while (frames_to_push) {
37 // Get the current write block.
38 AudioBus* current_block = audio_blocks_[write_block_];
39
40 // Figure out what segment sizes we need when adding the new content to
41 // the FIFO.
42 const int push_frames =
43 std::min(block_frames_ - write_pos_, frames_to_push);
44
45 // Deinterleave the content to the FIFO and update the |write_pos_|.
46 current_block->FromInterleavedPartial(
47 source_ptr, write_pos_, push_frames, bytes_per_sample);
48 write_pos_ = (write_pos_ + push_frames) % block_frames_;
49 if (!write_pos_) {
50 // The current block is completely filled, increment |write_block_| and
51 // |available_blocks_|.
52 write_block_ = (write_block_ + 1) % audio_blocks_.size();
53 ++available_blocks_;
54 }
55
56 source_ptr += push_frames * bytes_per_sample * channels_;
57 frames_to_push -= push_frames;
58 DCHECK_GE(frames_to_push, 0);
59 }
60 }
61
Consume()62 const AudioBus* AudioBlockFifo::Consume() {
63 DCHECK(available_blocks_);
64 AudioBus* audio_bus = audio_blocks_[read_block_];
65 read_block_ = (read_block_ + 1) % audio_blocks_.size();
66 --available_blocks_;
67 return audio_bus;
68 }
69
Clear()70 void AudioBlockFifo::Clear() {
71 write_pos_ = 0;
72 write_block_ = 0;
73 read_block_ = 0;
74 available_blocks_ = 0;
75 }
76
GetAvailableFrames() const77 int AudioBlockFifo::GetAvailableFrames() const {
78 return available_blocks_ * block_frames_ + write_pos_;
79 }
80
GetUnfilledFrames() const81 int AudioBlockFifo::GetUnfilledFrames() const {
82 const int unfilled_frames =
83 (audio_blocks_.size() - available_blocks_) * block_frames_ - write_pos_;
84 DCHECK_GE(unfilled_frames, 0);
85 return unfilled_frames;
86 }
87
IncreaseCapacity(int blocks)88 void AudioBlockFifo::IncreaseCapacity(int blocks) {
89 DCHECK_GT(blocks, 0);
90
91 // Create |blocks| of audio buses and insert them to the containers.
92 audio_blocks_.reserve(audio_blocks_.size() + blocks);
93
94 const int original_size = audio_blocks_.size();
95 for (int i = 0; i < blocks; ++i) {
96 audio_blocks_.push_back(
97 AudioBus::Create(channels_, block_frames_).release());
98 }
99
100 if (!original_size)
101 return;
102
103 std::rotate(audio_blocks_.begin() + read_block_,
104 audio_blocks_.begin() + original_size,
105 audio_blocks_.end());
106
107 // Update the write pointer if it is on top of the new inserted blocks.
108 if (write_block_ >= read_block_)
109 write_block_ += blocks;
110
111 // Update the read pointers correspondingly.
112 read_block_ += blocks;
113
114 DCHECK_LT(read_block_, static_cast<int>(audio_blocks_.size()));
115 DCHECK_LT(write_block_, static_cast<int>(audio_blocks_.size()));
116 }
117
118 } // namespace media
119