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// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef CONTENT_BROWSER_SPEECH_AUDIO_BUFFER_H_
#define CONTENT_BROWSER_SPEECH_AUDIO_BUFFER_H_
#include <stddef.h>
#include <stdint.h>
#include <string>
#include "base/containers/circular_deque.h"
#include "base/macros.h"
#include "base/memory/ref_counted.h"
#include "content/common/content_export.h"
namespace content {
// Models a chunk derived from an AudioBuffer.
class CONTENT_EXPORT AudioChunk :
public base::RefCountedThreadSafe<AudioChunk> {
public:
explicit AudioChunk(int bytes_per_sample);
// Creates a chunk of |length| bytes, initialized to zeros.
AudioChunk(size_t length, int bytes_per_sample);
AudioChunk(const uint8_t* data, size_t length, int bytes_per_sample);
bool IsEmpty() const;
int bytes_per_sample() const { return bytes_per_sample_; }
size_t NumSamples() const;
const std::string& AsString() const;
int16_t GetSample16(size_t index) const;
const int16_t* SamplesData16() const;
uint8_t* writable_data() {
return reinterpret_cast<uint8_t*>(&data_string_[0]);
}
private:
friend class base::RefCountedThreadSafe<AudioChunk>;
~AudioChunk() {}
std::string data_string_;
const int bytes_per_sample_;
DISALLOW_COPY_AND_ASSIGN(AudioChunk);
};
// Models an audio buffer. The current implementation relies on on-demand
// allocations of AudioChunk(s) (which uses a string as storage).
class AudioBuffer {
public:
explicit AudioBuffer(int bytes_per_sample);
~AudioBuffer();
// Enqueues a copy of |length| bytes of |data| buffer.
void Enqueue(const uint8_t* data, size_t length);
// Dequeues, in FIFO order, a single chunk respecting the length of the
// corresponding Enqueue call (in a nutshell: multiple Enqueue calls followed
// by DequeueSingleChunk calls will return the individual chunks without
// merging them).
scoped_refptr<AudioChunk> DequeueSingleChunk();
// Dequeues all previously enqueued chunks, merging them in a single chunk.
scoped_refptr<AudioChunk> DequeueAll();
// Removes and frees all the enqueued chunks.
void Clear();
// Checks whether the buffer is empty.
bool IsEmpty() const;
private:
using ChunksContainer = base::circular_deque<scoped_refptr<AudioChunk>>;
ChunksContainer chunks_;
const int bytes_per_sample_;
DISALLOW_COPY_AND_ASSIGN(AudioBuffer);
};
} // namespace content
#endif // CONTENT_BROWSER_SPEECH_AUDIO_BUFFER_H_