// Copyright 2013 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 MEDIA_AUDIO_SOUNDS_WAV_AUDIO_HANDLER_H_
#define MEDIA_AUDIO_SOUNDS_WAV_AUDIO_HANDLER_H_

#include "base/strings/string_piece.h"
#include "base/time/time.h"
#include "media/base/media_export.h"

namespace media {

class AudioBus;

// This class provides the input from wav file format.  See
// https://ccrma.stanford.edu/courses/422/projects/WaveFormat/
class MEDIA_EXPORT WavAudioHandler {
 public:
  explicit WavAudioHandler(const base::StringPiece& wav_data);
  virtual ~WavAudioHandler();

  // Returns true when cursor points to the end of the track.
  bool AtEnd(size_t cursor) const;

  // Copies the audio data to |bus| starting from the |cursor| and in
  // the case of success stores the number of written bytes in
  // |bytes_written|. |bytes_written| should not be NULL.
  bool CopyTo(AudioBus* bus, size_t cursor, size_t* bytes_written) const;

  // Accessors.
  const base::StringPiece& data() const { return data_; }
  uint16_t num_channels() const { return num_channels_; }
  uint32_t sample_rate() const { return sample_rate_; }
  uint16_t bits_per_sample() const { return bits_per_sample_; }
  uint32_t total_frames() const { return total_frames_; }

  // Returns the duration of the entire audio chunk.
  base::TimeDelta GetDuration() const;

 private:
  // Parses a chunk of wav format data. Returns the length of the chunk.
  int ParseSubChunk(const base::StringPiece& data);

  // Parses the 'fmt' section chunk and stores |params_|.
  bool ParseFmtChunk(const base::StringPiece& data);

  // Parses the 'data' section chunk and stores |data_|.
  bool ParseDataChunk(const base::StringPiece& data);

  // Data part of the |wav_data_|.
  base::StringPiece data_;

  uint16_t num_channels_;
  uint32_t sample_rate_;
  uint16_t bits_per_sample_;
  uint32_t total_frames_;
};

}  // namespace media

#endif  // MEDIA_AUDIO_SOUNDS_WAV_AUDIO_HANDLER_H_