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