libs/PublicUtility/CABufferList.h

/*
Copyright (C) 2016 Apple Inc. All Rights Reserved.
See LICENSE.txt for this sample’s licensing information

Abstract:
Part of Core Audio Public Utility Classes
*/

#ifndef __CABufferList_h__
#define __CABufferList_h__

#include <stddef.h>
#include "CAStreamBasicDescription.h"
#include "CAXException.h"

void CAShowAudioBufferList(const AudioBufferList &abl, int framesToPrint, const AudioStreamBasicDescription &fmt, const char *label=NULL);
void CAShowAudioBufferList(const AudioBufferList &abl, int framesToPrint, int wordSize, const char *label=NULL);
extern "C" void CAShowAudioBufferList(const AudioBufferList *abl, int framesToPrint, int wordSize);
extern "C" int CrashIfClientProvidedBogusAudioBufferList(const AudioBufferList *abl, bool nullOK=false);

/* ____________________________________________________________________________
//	CABufferList - variable length buffer list

	This class is designed for use in non-simplistic cases. For AudioUnits, AUBufferList
	is preferred.

	CABufferList can be used in one of two ways:
		- as mutable pointers into non-owned memory
		- as an immutable array of buffers (owns its own memory).

 	All buffers are assumed to have the same format (number of channels, word size), so that
		we can assume their mDataByteSizes are all the same.
____________________________________________________________________________ */
class CABufferList {
public:
	void *	operator new(size_t /*size*/, int nBuffers) {
				return ::operator new(sizeof(CABufferList) + (nBuffers-1) * sizeof(AudioBuffer));
			}
	static CABufferList *	New(const char *name, const CAStreamBasicDescription &format)
	{
		UInt32 numBuffers = format.NumberChannelStreams(), channelsPerBuffer = format.NumberInterleavedChannels();
		return new(numBuffers) CABufferList(name, numBuffers, channelsPerBuffer);
	}
	static CABufferList *	New(const CAStreamBasicDescription &format) { return New("", format); }

	static CABufferList *	New(UInt32 numBuffers, UInt32 channelsPerBuffer, const char *name="") {
		return new(numBuffers) CABufferList(name, numBuffers, channelsPerBuffer);
	}

protected:
	CABufferList(const char *name, UInt32 numBuffers, UInt32 channelsPerBuffer) :
		mName(name),
		mBufferMemory(NULL),
		mBufferCapacity(0)
	{
		//XAssert(numBuffers > 0 /*&& channelsPerBuffer > 0*/);
		mABL.mNumberBuffers = numBuffers;
		AudioBuffer *buf = mABL.mBuffers;
		for (UInt32 i = mABL.mNumberBuffers; i--; ++buf) {
			buf->mNumberChannels = channelsPerBuffer;
			buf->mDataByteSize = 0;
			buf->mData = NULL;
		}
	}

public:
	~CABufferList()
	{
		if (mBufferMemory)
			delete[] mBufferMemory;
	}

	const char *				Name() { return mName; }

	const AudioBufferList &		GetBufferList() const { return mABL; }

	AudioBufferList &			GetModifiableBufferList() { return _GetBufferList(); }

	UInt32		GetNumberBuffers() const { return mABL.mNumberBuffers; }

	UInt32		GetNumBytes() const
	{
		return mABL.mBuffers[0].mDataByteSize;
	}

	void		SetBytes(UInt32 nBytes, void *data)
	{
		VerifyNotTrashingOwnedBuffer();
		XAssert(mABL.mNumberBuffers == 1);
		mABL.mBuffers[0].mDataByteSize = nBytes;
		mABL.mBuffers[0].mData = data;
	}

	void		CopyAllFrom(CABufferList *srcbl, CABufferList *ptrbl)
					// copies bytes from srcbl
					// make ptrbl reflect the length copied
					// note that srcbl may be same as ptrbl!
	{
		// Note that this buffer *can* own memory and its pointers/lengths are not
		// altered; only its buffer contents, which are copied from srcbl.
		// The pointers/lengths in ptrbl are updated to reflect the addresses/lengths
		// of the copied data, and srcbl's contents are consumed.
		ptrbl->VerifyNotTrashingOwnedBuffer();
		UInt32 nBytes = srcbl->GetNumBytes();
		AudioBuffer *mybuf = mABL.mBuffers, *srcbuf = srcbl->mABL.mBuffers,
					*ptrbuf = ptrbl->mABL.mBuffers;
		for (UInt32 i = mABL.mNumberBuffers; i--; ++mybuf, ++srcbuf, ++ptrbuf) {
			memmove(mybuf->mData, srcbuf->mData, srcbuf->mDataByteSize);
			ptrbuf->mData = mybuf->mData;
			ptrbuf->mDataByteSize = srcbuf->mDataByteSize;
		}
		if (srcbl != ptrbl)
			srcbl->BytesConsumed(nBytes);
	}

	// copies data from another buffer list.
	void		CopyDataFrom(const AudioBufferList &other)
	{
		for (unsigned i = 0; i < other.mNumberBuffers; ++i) {
			XAssert(mBufferCapacity == 0 || other.mBuffers[i].mDataByteSize <= mBufferCapacity);
			memcpy(mABL.mBuffers[i].mData, other.mBuffers[i].mData,
				mABL.mBuffers[i].mDataByteSize = other.mBuffers[i].mDataByteSize);
		}
	}

	void		AppendFrom(CABufferList *blp, UInt32 nBytes)
	{
		// this may mutate a buffer that owns memory.
		AudioBuffer *mybuf = mABL.mBuffers, *srcbuf = blp->mABL.mBuffers;
		for (UInt32 i = mABL.mNumberBuffers; i--; ++mybuf, ++srcbuf) {
			XAssert(nBytes <= srcbuf->mDataByteSize);
			XAssert(mBufferCapacity == 0 || mybuf->mDataByteSize + nBytes <= mBufferCapacity);
			memcpy((Byte *)mybuf->mData + mybuf->mDataByteSize, srcbuf->mData, nBytes);
			mybuf->mDataByteSize += nBytes;
		}
		blp->BytesConsumed(nBytes);
	}

	void		PadWithZeroes(UInt32 desiredBufferSize)
					// for cases where an algorithm (e.g. SRC) requires some
					// padding to create silence following end-of-file
	{
		XAssert(mBufferCapacity == 0 || desiredBufferSize <= mBufferCapacity);
		if (GetNumBytes() > desiredBufferSize) return;
		AudioBuffer *buf = mABL.mBuffers;
		for (UInt32 i = mABL.mNumberBuffers; i--; ++buf) {
			memset((Byte *)buf->mData + buf->mDataByteSize, 0, desiredBufferSize - buf->mDataByteSize);
			buf->mDataByteSize = desiredBufferSize;
		}
	}

	void		SetToZeroes(UInt32 nBytes)
	{
		XAssert(mBufferCapacity == 0 || nBytes <= mBufferCapacity);
		AudioBuffer *buf = mABL.mBuffers;
		for (UInt32 i = mABL.mNumberBuffers; i--; ++buf) {
			memset((Byte *)buf->mData, 0, nBytes);
			buf->mDataByteSize = nBytes;
		}
	}

	void		Reset()
	{
		DeallocateBuffers();
	}

	Boolean		SameDataAs(const CABufferList* anotherBufferList)
	{
		// check to see if two buffer lists point to the same memory.
		if (mABL.mNumberBuffers != anotherBufferList->mABL.mNumberBuffers) return false;

		for (UInt32 i = 0; i < mABL.mNumberBuffers; ++i) {
			if (mABL.mBuffers[i].mData != anotherBufferList->mABL.mBuffers[i].mData) return false;
		}
		return true;
	}

	void		BytesConsumed(UInt32 nBytes)
					// advance buffer pointers, decrease buffer sizes
	{
		VerifyNotTrashingOwnedBuffer();
		AudioBuffer *buf = mABL.mBuffers;
		for (UInt32 i = mABL.mNumberBuffers; i--; ++buf) {
			XAssert(nBytes <= buf->mDataByteSize);
			buf->mData = (Byte *)buf->mData + nBytes;
			buf->mDataByteSize -= nBytes;
		}
	}

	void		SetFrom(const AudioBufferList *abl)
	{
		VerifyNotTrashingOwnedBuffer();
		memcpy(&_GetBufferList(), abl, (char *)&abl->mBuffers[abl->mNumberBuffers] - (char *)abl);
	}

	void		SetFrom(const CABufferList *blp)
	{
		SetFrom(&blp->GetBufferList());
	}

	void		SetFrom(const AudioBufferList *abl, UInt32 nBytes)
	{
		VerifyNotTrashingOwnedBuffer();
		AudioBuffer *mybuf = mABL.mBuffers;
		const AudioBuffer *srcbuf = abl->mBuffers;
		for (UInt32 i = mABL.mNumberBuffers; i--; ++mybuf, ++srcbuf) {
			mybuf->mNumberChannels = srcbuf->mNumberChannels;
			mybuf->mDataByteSize = nBytes;
			mybuf->mData = srcbuf->mData;
		}
	}

	void		SetFrom(const CABufferList *blp, UInt32 nBytes)
	{
		SetFrom(&blp->GetBufferList(), nBytes);
	}

	AudioBufferList *	ToAudioBufferList(AudioBufferList *abl) const
	{
		memcpy(abl, &GetBufferList(), (char *)&abl->mBuffers[mABL.mNumberBuffers] - (char *)abl);
		return abl;
	}

	void		AllocateBuffers(UInt32 nBytes);
	void		AllocateBuffersAndCopyFrom(UInt32 nBytes, CABufferList *inCopyFromList, CABufferList *inSetPtrList);

	void		DeallocateBuffers();

	void		UseExternalBuffer(Byte *ptr, UInt32 nBytes);

	void		AdvanceBufferPointers(UInt32 nBytes) // $$$ ReducingSize
					// this is for bufferlists that function simply as
					// an array of pointers into another bufferlist, being advanced,
					// as in RenderOutput implementations
	{
		VerifyNotTrashingOwnedBuffer();
		AudioBuffer *buf = mABL.mBuffers;
		for (UInt32 i = mABL.mNumberBuffers; i--; ++buf) {
			buf->mData = (Byte *)buf->mData + nBytes;
			buf->mDataByteSize -= nBytes;
		}
	}

	void		SetNumBytes(UInt32 nBytes)
	{
		XAssert(mBufferCapacity == 0 || nBytes <= mBufferCapacity);
		AudioBuffer *buf = mABL.mBuffers;
		for (UInt32 i = mABL.mNumberBuffers; i--; ++buf)
			buf->mDataByteSize = nBytes;
	}

	void		Print(const char *label=NULL, int nframes=0, int wordSize=0) const
	{
		if (label == NULL)
			label = mName;
		printf("%s - ", label);
		CAShowAudioBufferList(&GetBufferList(), nframes, wordSize);
		if (mBufferMemory)
			printf("  owned memory @ 0x%p:\n", mBufferMemory);
	}

	UInt32		GetCapacityBytes() const { return mBufferCapacity; }

	template <typename T>
	T*			GetData(UInt32 inBuffer) {
		return static_cast<T*>(mABL.mBuffers[inBuffer].mData);
	}

protected:
	AudioBufferList &	_GetBufferList() { return mABL; }	// use with care
							// if we make this public, then we lose ability to call VerifyNotTrashingOwnedBuffer
	void				VerifyNotTrashingOwnedBuffer()
	{
		// This needs to be called from places where we are modifying the buffer pointers.
		// It's an error to modify the buffer pointers or lengths if we own the buffer memory.
		XAssert(mBufferMemory == NULL);
	}

	const char *						mName;	// for debugging
	Byte *								mBufferMemory;
	UInt32								mBufferCapacity;	// max mDataByteSize of each buffer
	AudioBufferList						mABL;
	// don't add anything here
};

#endif // __CABufferList_h__