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/*
Copyright 2018 Google Inc. All Rights Reserved.
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS-IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/
#ifndef RESONANCE_AUDIO_UTILS_BUFFER_UNPARTITIONER_H_
#define RESONANCE_AUDIO_UTILS_BUFFER_UNPARTITIONER_H_
#include <functional>
#include <memory>
#include "base/audio_buffer.h"
#include "base/logging.h"
namespace vraudio {
// Unpackages |AudioBuffer| into output buffers of arbitrary sizes.
class BufferUnpartitioner {
public:
// Callback to obtain input |AudioBuffer|s. Returns a nullptr if no buffers
// are available.
typedef std::function<const AudioBuffer*()> GetBufferCallback;
// Constructor.
//
// @param num_channels Number of audio channels in input and output buffers.
// @param frames_per_buffer Number of frames per input buffer.
// @param buffer_callback Callback to receive output |AudioBuffer|s.
BufferUnpartitioner(size_t num_channels, size_t frames_per_buffer,
GetBufferCallback buffer_callback);
// Returns the number of input buffers required for a given number of output
// frames and based on the current fill state of the internal |temp_buffer_|.
//
// @param num_output_frames Number of output frames.
// @return Number of required input |AudioBuffer|s.
size_t GetNumBuffersRequestedForNumInputFrames(
size_t num_output_frames) const;
// Returns the number of buffered frames in internal |temp_buffer_|.
size_t GetNumBufferedFrames() const;
// Requests an interleaved int16 output buffer. This method triggers
// |GetBufferCallback|.
//
// @param output_buffer Interleaved output buffer to write to.
// @param num_channels Number of channels in output buffer.
// @param num_frames Number of frames in output buffer.
// @return Number of frames actually written.
size_t GetBuffer(int16* output_buffer, size_t num_channels,
size_t num_frames);
// Requests an interleaved float output buffer. This method triggers
// |GetBufferCallback|.
//
// @param output_buffer Interleaved output buffer to write to.
// @param num_channels Number of channels in output buffer.
// @param num_frames Number of frames in output buffer.
// @return Number of frames actually written.
size_t GetBuffer(float* output_buffer, size_t num_channels,
size_t num_frames);
// Requests a planar int16 output buffer. This method triggers
// |GetBufferCallback|.
//
// @param output_buffer Planar output buffer to write to.
// @param num_channels Number of channels in output buffer.
// @param num_frames Number of frames in output buffer.
// @return Number of frames actually written.
size_t GetBuffer(int16** output_buffer, size_t num_channels,
size_t num_frames);
// Requests a planar float output buffer. This method triggers
// |GetBufferCallback|.
//
// @param output_buffer Planar output buffer to write to.
// @param num_channels Number of channels in output buffer.
// @param num_frames Number of frames in output buffer.
// @return Number of frames actually written.
size_t GetBuffer(float** output_buffer, size_t num_channels,
size_t num_frames);
// Clears internal temporary buffer that holds remaining audio frames.
void Clear();
private:
// Returns the number of frames that are buffered in |current_input_buffer_|.
//
// @return Number of frames in |current_input_buffer_|. If
// |current_input_buffer_| is undefined, it returns 0.
size_t GetNumFramesAvailableInBuffer() const;
// Writes output buffer into target buffer. Supported buffer types are planar
// and interleaved floating point abd interleaved int16 output. This method
// triggers |GetBufferCallback|.
//
// @tparam BufferType Output buffer type.
// @param buffer Output buffer to write to.
// @param num_channels Number of channels in output buffer.
// @param num_frames Number of frames in output buffer.
// @return Number of frames actually written.
template <typename BufferType>
size_t GetBufferTemplated(BufferType buffer, size_t num_channels,
size_t num_frames);
// Number of channels in output buffers.
const size_t num_channels_;
// Number of frames per buffer in output buffers.
const size_t frames_per_buffer_;
// Callback to request input |AudioBuffer|s.
const GetBufferCallback buffer_callback_;
// Temporary buffer containing remaining audio frames.
const AudioBuffer* current_input_buffer_; // Not owned.
// Current read position in |current_input_buffer_|.
size_t current_buffer_read_offset_frames_;
};
} // namespace vraudio
#endif // RESONANCE_AUDIO_UTILS_BUFFER_UNPARTITIONER_H_