CABufferList.h

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#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);
    }

protected:
    CABufferList(const char *name, UInt32 numBuffers, UInt32 channelsPerBuffer) :
        mName(name),
        mBufferMemory(NULL)
    {
        //XAssert(numBuffers > 0 /*&& channelsPerBuffer > 0*/);
        mNumberBuffers = numBuffers;
        AudioBuffer *buf = mBuffers;
        for (UInt32 i = 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 *(AudioBufferList *)&mNumberBuffers; }
    
    AudioBufferList &           GetModifiableBufferList()
    {
        VerifyNotTrashingOwnedBuffer();
        return _GetBufferList();
    }
    
    UInt32      GetNumberBuffers() const { return mNumberBuffers; }
    
    UInt32      GetNumBytes() const
    {
        return mBuffers[0].mDataByteSize;
    }
    
    void        SetBytes(UInt32 nBytes, void *data)
    {
        VerifyNotTrashingOwnedBuffer();
        XAssert(mNumberBuffers == 1);
        mBuffers[0].mDataByteSize = nBytes;
        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 = mBuffers, *srcbuf = srcbl->mBuffers,
                    *ptrbuf = ptrbl->mBuffers;
        for (UInt32 i = 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);
    }
    
    void        AppendFrom(CABufferList *blp, UInt32 nBytes)
    {
        VerifyNotTrashingOwnedBuffer();
        AudioBuffer *mybuf = mBuffers, *srcbuf = blp->mBuffers;
        for (UInt32 i = mNumberBuffers; i--; ++mybuf, ++srcbuf) {
            XAssert(nBytes <= srcbuf->mDataByteSize);
            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
    {
        VerifyNotTrashingOwnedBuffer();
        if (GetNumBytes() > desiredBufferSize) return;
        AudioBuffer *buf = mBuffers;
        for (UInt32 i = mNumberBuffers; i--; ++buf) {
            memset((Byte *)buf->mData + buf->mDataByteSize, 0, desiredBufferSize - buf->mDataByteSize);
            buf->mDataByteSize = desiredBufferSize;
        }
    }
    
    void        SetToZeroes(UInt32 nBytes)
    {
        VerifyNotTrashingOwnedBuffer();
        AudioBuffer *buf = mBuffers;
        for (UInt32 i = 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 (mNumberBuffers != anotherBufferList->mNumberBuffers) return false;
        
        for (UInt32 i = 0; i < mNumberBuffers; ++i) {
            if (mBuffers[i].mData != anotherBufferList->mBuffers[i].mData) return false;
        }
        return true;
    }
    
    void        BytesConsumed(UInt32 nBytes)
                    // advance buffer pointers, decrease buffer sizes
    {
        VerifyNotTrashingOwnedBuffer();
        AudioBuffer *buf = mBuffers;
        for (UInt32 i = 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 = mBuffers;
        const AudioBuffer *srcbuf = abl->mBuffers;
        for (UInt32 i = 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[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)
                    // this is for bufferlists that function simply as
                    // an array of pointers into another bufferlist, being advanced,
                    // as in RenderOutput implementations
    {
        VerifyNotTrashingOwnedBuffer();
        AudioBuffer *buf = mBuffers;
        for (UInt32 i = mNumberBuffers; i--; ++buf) {
            buf->mData = (Byte *)buf->mData + nBytes;
            buf->mDataByteSize -= nBytes;
        }
    }
    
    void        SetNumBytes(UInt32 nBytes)
    {
        VerifyNotTrashingOwnedBuffer();
        AudioBuffer *buf = mBuffers;
        for (UInt32 i = 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);
    }

protected:
    AudioBufferList &   _GetBufferList() { return *(AudioBufferList *)&mNumberBuffers; }    // 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 list.
        // 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;
    // the rest must exactly mirror the structure of AudioBufferList
    UInt32                              mNumberBuffers;
    AudioBuffer                         mBuffers[1];
};

#endif // __CABufferList_h__