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1 // Copyright (c) 2012 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 "media/base/audio_fifo.h" | |
6 | |
7 #include "media/audio/audio_parameters.h" | |
8 #include "base/logging.h" | |
9 | |
10 namespace media { | |
11 | |
12 static void GetSizes(int pos, int max_size, int src_size, | |
13 int* size, int* wrap_size) { | |
DaleCurtis
2012/09/05 10:34:18
Indent to start with (. (Or move the line above do
henrika (OOO until Aug 14)
2012/09/05 12:49:04
Done.
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14 if (pos + src_size > max_size) { | |
DaleCurtis
2012/09/05 10:34:18
CHECK() size, wrap_size?
henrika (OOO until Aug 14)
2012/09/05 12:49:04
See comment above about using CHECK() in this clas
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15 // Wrapping is required => derive size of each segment. | |
16 *size = max_size - pos; | |
17 *wrap_size = src_size - *size; | |
18 } else { | |
19 // Wrapping is not required. | |
20 *size = src_size; | |
21 *wrap_size = 0; | |
22 } | |
23 } | |
24 | |
25 static int UpdatePos(int pos, int step, int max_size) { | |
26 return ((pos + step) % max_size); | |
27 } | |
28 | |
29 AudioFifo::AudioFifo(int channels, int frames) | |
30 : audio_bus_(AudioBus::Create(channels, frames)), | |
31 size_(0), | |
32 read_pos_(0), | |
33 write_pos_(0) { | |
34 audio_bus_->Zero(); | |
Chris Rogers
2012/09/04 20:07:20
I don't think Zero() is necessary since Create() s
henrika (OOO until Aug 14)
2012/09/05 10:14:36
removed.
DaleCurtis
2012/09/05 10:34:18
Create() doesn't Zero, so if it needs to be Zero'd
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35 } | |
36 | |
37 AudioFifo::~AudioFifo() {} | |
38 | |
39 bool AudioFifo::Append(const AudioBus* source) { | |
40 DCHECK(source); | |
41 DCHECK_EQ(source->channels(), audio_bus_->channels()); | |
42 | |
43 // Ensure that there is space for the new data in the FIFO. | |
44 const int source_size = source->frames(); | |
45 if (size_ + source_size > max_size()) { | |
46 DLOG(ERROR) << "FIFO overflow."; | |
47 return false; | |
48 } | |
49 | |
50 // Figure out if wrapping is needed and if so what segment sizes we need | |
51 // when adding the new audio bus content to the FIFO. | |
52 int append_size = 0; | |
DaleCurtis
2012/09/05 10:34:18
Can these names include "frames" or something more
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53 int wrap_size = 0; | |
54 GetSizes(write_pos_, max_size(), source_size, &append_size, &wrap_size); | |
55 | |
56 // Copy all channels from the source to the FIFO. Wrap around if needed. | |
57 for (int ch = 0; ch < source->channels(); ++ch) { | |
58 float* dest = audio_bus_->channel(ch); | |
59 const float* src = source->channel(ch); | |
60 | |
61 // Append part of (or the complete) source to the FIFO. | |
62 memcpy(&dest[write_pos_], &src[0], append_size * sizeof(src[0])); | |
Chris Rogers
2012/09/04 20:07:20
why "&dest[write_pos_]" instead of "dest + write_p
henrika (OOO until Aug 14)
2012/09/05 10:14:36
I prefer the "C++ way" and not the "C way" since &
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63 if (wrap_size > 0) { | |
64 // Wrapping is needed: copy remaining part from the source to the FIFO. | |
65 memcpy(&dest[0], &src[append_size], wrap_size * sizeof(src[0])); | |
Chris Rogers
2012/09/04 20:07:20
why not "dest" instead of "&dest[0]"
henrika (OOO until Aug 14)
2012/09/05 10:14:36
ditto
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66 } | |
67 } | |
68 | |
69 size_ += source_size; | |
70 DCHECK_LE(size_, max_size()); | |
71 write_pos_ = UpdatePos(write_pos_, source_size, max_size()); | |
72 return true; | |
73 } | |
74 | |
75 bool AudioFifo::Remove(AudioBus* destination) { | |
76 DCHECK(destination); | |
77 DCHECK_EQ(destination->channels(), audio_bus_->channels()); | |
78 | |
79 // It is not possible to ask for more data than what is available in the FIFO. | |
80 const int dest_size = destination->frames(); | |
81 if (dest_size > size_) { | |
82 DLOG(ERROR) << "FIFO underrun."; | |
83 return false; | |
84 } | |
85 | |
86 // Figure out if wrapping is needed and if so what segment sizes we need | |
87 // when removing audio bus content from the FIFO. | |
88 int remove_size = 0; | |
89 int wrap_size = 0; | |
90 GetSizes(read_pos_, max_size(), dest_size, &remove_size, &wrap_size); | |
91 | |
92 // Remove all channels from the FIFO and copy the content to the | |
Chris Rogers
2012/09/04 20:07:20
"Remove all channels from the FIFO" sounds a littl
henrika (OOO until Aug 14)
2012/09/05 10:14:36
Done.
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93 // destination. Wrap around if needed. | |
94 for (int ch = 0; ch < destination->channels(); ++ch) { | |
95 float* dest = destination->channel(ch); | |
96 const float* src = audio_bus_->channel(ch); | |
97 | |
98 // Append part of (or the complete) source to the destination. | |
DaleCurtis
2012/09/05 10:34:18
Update comment.
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99 memcpy(&dest[0], &src[read_pos_], remove_size * sizeof(src[0])); | |
Chris Rogers
2012/09/04 20:07:20
"dest" instead of "&dest[0]", etc. here and in mem
henrika (OOO until Aug 14)
2012/09/05 10:14:36
ditto
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100 if (wrap_size > 0) { | |
101 // Wrapping is needed: copy remaining part to the destination. | |
102 memcpy(&dest[wrap_size], &src[0], wrap_size * sizeof(src[0])); | |
103 } | |
104 } | |
105 | |
106 size_ -= dest_size; | |
107 read_pos_ = UpdatePos(read_pos_, dest_size, max_size()); | |
108 return true; | |
109 } | |
110 | |
111 void AudioFifo::Clear() { | |
112 size_ = 0; | |
113 read_pos_ = 0; | |
114 write_pos_ = 0; | |
115 } | |
116 | |
117 } // namespace media | |
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