gecko-dev/content/media/webaudio/AudioBuffer.h

132 lines
3.7 KiB
C++

/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim:set ts=2 sw=2 sts=2 et cindent: */
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
#ifndef AudioBuffer_h_
#define AudioBuffer_h_
#include "nsWrapperCache.h"
#include "nsCycleCollectionParticipant.h"
#include "mozilla/Attributes.h"
#include "EnableWebAudioCheck.h"
#include "nsAutoPtr.h"
#include "nsTArray.h"
#include "AudioContext.h"
#include "AudioSegment.h"
#include "AudioNodeEngine.h"
struct JSContext;
class JSObject;
namespace mozilla {
class ErrorResult;
namespace dom {
/**
* An AudioBuffer keeps its data either in the mJSChannels objects, which
* are Float32Arrays, or in mSharedChannels if the mJSChannels objects have
* been neutered.
*/
class AudioBuffer MOZ_FINAL : public nsISupports,
public nsWrapperCache,
public EnableWebAudioCheck
{
public:
AudioBuffer(AudioContext* aContext, uint32_t aLength,
float aSampleRate);
~AudioBuffer();
// This function needs to be called in order to allocate
// all of the channels. It is fallible!
bool InitializeBuffers(uint32_t aNumberOfChannels,
JSContext* aJSContext);
NS_DECL_CYCLE_COLLECTING_ISUPPORTS
NS_DECL_CYCLE_COLLECTION_SCRIPT_HOLDER_CLASS(AudioBuffer)
AudioContext* GetParentObject() const
{
return mContext;
}
virtual JSObject* WrapObject(JSContext* aCx, JSObject* aScope) MOZ_OVERRIDE;
float SampleRate() const
{
return mSampleRate;
}
int32_t Length() const
{
return mLength;
}
double Duration() const
{
return mLength / static_cast<double> (mSampleRate);
}
uint32_t NumberOfChannels() const
{
return mJSChannels.Length();
}
/**
* If mSharedChannels is non-null, copies its contents to
* new Float32Arrays in mJSChannels. Returns a Float32Array.
*/
JSObject* GetChannelData(JSContext* aJSContext, uint32_t aChannel,
ErrorResult& aRv);
JSObject* GetChannelData(uint32_t aChannel) const {
// Doesn't perform bounds checking
MOZ_ASSERT(aChannel < mJSChannels.Length());
return mJSChannels[aChannel];
}
/**
* Returns a ThreadSharedFloatArrayBufferList containing the sample data
* at aRate. Sets *aLength to the number of samples per channel.
*/
ThreadSharedFloatArrayBufferList* GetThreadSharedChannelsForRate(JSContext* aContext,
uint32_t aRate,
uint32_t* aLength);
// aContents should either come from JS_AllocateArrayBufferContents or
// JS_StealArrayBufferContents.
void SetChannelDataFromArrayBufferContents(JSContext* aJSContext,
uint32_t aChannel,
void* aContents);
protected:
void RestoreJSChannelData(JSContext* aJSContext);
void ClearJSChannels();
nsRefPtr<AudioContext> mContext;
// Float32Arrays
AutoFallibleTArray<JSObject*,2> mJSChannels;
// mSharedChannels aggregates the data from mJSChannels. This is non-null
// if and only if the mJSChannels are neutered.
nsRefPtr<ThreadSharedFloatArrayBufferList> mSharedChannels;
// One-element cache of resampled data. Can be non-null only if mSharedChannels
// is non-null.
nsRefPtr<ThreadSharedFloatArrayBufferList> mResampledChannels;
uint32_t mResampledChannelsRate;
uint32_t mResampledChannelsLength;
uint32_t mLength;
float mSampleRate;
};
}
}
#endif