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/*
* Copyright (C) 2010 Google Inc. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of Apple Computer, Inc. ("Apple") nor the names of
* its contributors may be used to endorse or promote products derived
* from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY
* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR ANY
* DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#ifndef THIRD_PARTY_BLINK_RENDERER_PLATFORM_AUDIO_AUDIO_CHANNEL_H_
#define THIRD_PARTY_BLINK_RENDERER_PLATFORM_AUDIO_AUDIO_CHANNEL_H_
#include <memory>
#include "base/numerics/checked_math.h"
#include "third_party/blink/renderer/platform/audio/audio_array.h"
#include "third_party/blink/renderer/platform/platform_export.h"
#include "third_party/blink/renderer/platform/wtf/allocator.h"
namespace blink {
// An AudioChannel represents a buffer of non-interleaved floating-point audio
// samples.
// The PCM samples are normally assumed to be in a nominal range -1.0 -> +1.0
class PLATFORM_EXPORT AudioChannel {
USING_FAST_MALLOC(AudioChannel);
public:
// Memory can be externally referenced, or can be internally allocated with an
// AudioFloatArray.
// Reference an external buffer.
AudioChannel(float* storage, size_t length)
: length_(length), raw_pointer_(storage), silent_(false) {}
// Manage storage for us.
explicit AudioChannel(size_t length)
: length_(length), raw_pointer_(nullptr), silent_(true) {
mem_buffer_ = std::make_unique<AudioFloatArray>(length);
}
// A "blank" audio channel -- must call Set() before it's useful...
AudioChannel() : length_(0), raw_pointer_(nullptr), silent_(true) {}
// Redefine the memory for this channel. |storage| represents external memory
// not managed by this object.
void Set(float* storage, size_t length) {
mem_buffer_.reset(); // cleanup managed storage
raw_pointer_ = storage;
length_ = length;
silent_ = false;
}
// How many sample-frames do we contain?
size_t length() const { return length_; }
// ResizeSmaller() can only be called with a new length <= the current length.
// The data stored in the bus will remain undisturbed.
void ResizeSmaller(size_t new_length);
// Direct access to PCM sample data. Non-const accessor clears silent flag.
float* MutableData() {
ClearSilentFlag();
return raw_pointer_ ? raw_pointer_ : mem_buffer_->Data();
}
const float* Data() const {
return raw_pointer_ ? raw_pointer_ : mem_buffer_->Data();
}
// Zeroes out all sample values in buffer.
void Zero() {
if (silent_)
return;
silent_ = true;
if (mem_buffer_.get()) {
mem_buffer_->Zero();
} else {
memset(raw_pointer_, 0,
base::CheckMul(sizeof(float), length_).ValueOrDie());
}
}
// Clears the silent flag.
void ClearSilentFlag() { silent_ = false; }
bool IsSilent() const { return silent_; }
// Scales all samples by the same amount.
void Scale(float scale);
// A simple memcpy() from the source channel
void CopyFrom(const AudioChannel* source_channel);
// Copies the given range from the source channel.
void CopyFromRange(const AudioChannel* source_channel,
unsigned start_frame,
unsigned end_frame);
// Sums (with unity gain) from the source channel.
void SumFrom(const AudioChannel* source_channel);
// Returns maximum absolute value (useful for normalization).
float MaxAbsValue() const;
private:
size_t length_;
float* raw_pointer_;
std::unique_ptr<AudioFloatArray> mem_buffer_;
bool silent_;
DISALLOW_COPY_AND_ASSIGN(AudioChannel);
};
} // namespace blink
#endif // THIRD_PARTY_BLINK_RENDERER_PLATFORM_AUDIO_AUDIO_CHANNEL_H_