content/browser/speech/audio_buffer.cc

   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 "content/browser/speech/audio_buffer.h"
   6
   7 #include "base/logging.h"
   8
   9 namespace content {
  10
  11 AudioChunk::AudioChunk(int bytes_per_sample)
  12     : bytes_per_sample_(bytes_per_sample) {
  13 }
  14
  15 AudioChunk::AudioChunk(size_t length, int bytes_per_sample)
  16     : data_string_(length, '\0'), bytes_per_sample_(bytes_per_sample) {
  17   DCHECK_EQ(length % bytes_per_sample, 0U);
  18 }
  19
  20 AudioChunk::AudioChunk(const uint8* data, size_t length, int bytes_per_sample)
  21     : data_string_(reinterpret_cast<const char*>(data), length),
  22       bytes_per_sample_(bytes_per_sample) {
  23   DCHECK_EQ(length % bytes_per_sample, 0U);
  24 }
  25
  26 bool AudioChunk::IsEmpty() const {
  27   return data_string_.empty();
  28 }
  29
  30 size_t AudioChunk::NumSamples() const {
  31   return data_string_.size() / bytes_per_sample_;
  32 }
  33
  34 const std::string& AudioChunk::AsString() const {
  35   return data_string_;
  36 }
  37
  38 int16 AudioChunk::GetSample16(size_t index) const {
  39   DCHECK(index < (data_string_.size() / sizeof(int16)));
  40   return SamplesData16()[index];
  41 }
  42
  43 const int16* AudioChunk::SamplesData16() const {
  44   return reinterpret_cast<const int16*>(data_string_.data());
  45 }
  46
  47 AudioBuffer::AudioBuffer(int bytes_per_sample)
  48     : bytes_per_sample_(bytes_per_sample) {
  49   DCHECK(bytes_per_sample == 1 ||
  50          bytes_per_sample == 2 ||
  51          bytes_per_sample == 4);
  52 }
  53
  54 AudioBuffer::~AudioBuffer() {
  55   Clear();
  56 }
  57
  58 void AudioBuffer::Enqueue(const uint8* data, size_t length) {
  59   chunks_.push_back(new AudioChunk(data, length, bytes_per_sample_));
  60 }
  61
  62 scoped_refptr<AudioChunk> AudioBuffer::DequeueSingleChunk() {
  63   DCHECK(!chunks_.empty());
  64   scoped_refptr<AudioChunk> chunk(chunks_.front());
  65   chunks_.pop_front();
  66   return chunk;
  67 }
  68
  69 scoped_refptr<AudioChunk> AudioBuffer::DequeueAll() {
  70   size_t resulting_length = 0;
  71   ChunksContainer::const_iterator it;
  72   // In order to improve performance, calulate in advance the total length
  73   // and then copy the chunks.
  74   for (it = chunks_.begin(); it != chunks_.end(); ++it) {
  75     resulting_length += (*it)->AsString().length();
  76   }
  77   scoped_refptr<AudioChunk> chunk(
  78       new AudioChunk(resulting_length, bytes_per_sample_));
  79   uint8* dest = chunk->writable_data();
  80   for (it = chunks_.begin(); it != chunks_.end(); ++it) {
  81     memcpy(dest, (*it)->AsString().data(), (*it)->AsString().length());
  82     dest += (*it)->AsString().length();
  83   }
  84   Clear();
  85   return chunk;
  86 }
  87
  88 void AudioBuffer::Clear() {
  89   chunks_.clear();
  90 }
  91
  92 bool AudioBuffer::IsEmpty() const {
  93   return chunks_.empty();
  94 }
  95
  96 }  // namespace content