audiofilereaderthread.c

SDL库 在进行视频显示程序spcaview安装时必须的库文件

            /* read data */
        result = theItem->Read(theItem, writePtr, &dataChunkSize);
        if (result != noErr && result != eofErr) {
            AudioFilePlayer *afp = (AudioFilePlayer *) theItem->GetParent(theItem);
            afp->DoNotification(afp, result);
            continue;
        }
        
        if (dataChunkSize != theItem->mChunkSize)
        {
            writePtr += dataChunkSize;

            /* can't exit yet.. we still have to pass the partial buffer back */
            SDL_memset(writePtr, 0, (theItem->mChunkSize - dataChunkSize));
        }
        
        theItem->mWriteToFirstBuffer = !theItem->mWriteToFirstBuffer;   /* switch buffers */
        
        if (result == eofErr)
            theItem->mReadFilePosition = theItem->mFileLength;
        else
            theItem->mReadFilePosition += dataChunkSize;        /* increment count */
    }
}

void delete_FileReaderThread(FileReaderThread *frt)
{
    if (frt != NULL)
    {
        delete_SDLOSXCAGuard(frt->mGuard);
        SDL_free(frt);
    }
}

FileReaderThread *new_FileReaderThread ()
{
    FileReaderThread *frt = (FileReaderThread *) SDL_malloc(sizeof (FileReaderThread));
    if (frt == NULL)
        return NULL;
    SDL_memset(frt, '\0', sizeof (*frt));

    frt->mGuard = new_SDLOSXCAGuard();
    if (frt->mGuard == NULL)
    {
        SDL_free(frt);
        return NULL;
    }

    #define SET_FILEREADERTHREAD_METHOD(m) frt->m = FileReaderThread_##m
    SET_FILEREADERTHREAD_METHOD(GetGuard);
    SET_FILEREADERTHREAD_METHOD(AddReader);
    SET_FILEREADERTHREAD_METHOD(RemoveReader);
    SET_FILEREADERTHREAD_METHOD(TryNextRead);
    SET_FILEREADERTHREAD_METHOD(ReadNextChunk);
    SET_FILEREADERTHREAD_METHOD(StartFixedPriorityThread);
    SET_FILEREADERTHREAD_METHOD(GetThreadBasePriority);
    SET_FILEREADERTHREAD_METHOD(DiskReaderEntry);
    #undef SET_FILEREADERTHREAD_METHOD

    frt->mThreadPriority = 62;
    return frt;
}


static FileReaderThread *sReaderThread;


static int    AudioFileManager_DoConnect (AudioFileManager *afm)
{
    if (!afm->mIsEngaged)
    {
        OSStatus result;

        /*afm->mReadFilePosition = 0;*/
        afm->mFinishedReadingData = 0;

        afm->mNumTimesAskedSinceFinished = 0;
        afm->mLockUnsuccessful = 0;
        
        UInt32 dataChunkSize;
        
        if ((afm->mFileLength - afm->mReadFilePosition) < afm->mChunkSize)
            dataChunkSize = afm->mFileLength - afm->mReadFilePosition;
        else
            dataChunkSize = afm->mChunkSize;
        
        result = afm->Read(afm, afm->mFileBuffer, &dataChunkSize);
           if (result) return 0; /*THROW_RESULT("AudioFileManager::DoConnect(): Read")*/

        afm->mReadFilePosition += dataChunkSize;
                
        afm->mWriteToFirstBuffer = 0;
        afm->mReadFromFirstBuffer = 1;

        sReaderThread->AddReader(sReaderThread);
        
        afm->mIsEngaged = 1;
    }
    /*
    else
        throw static_cast<OSStatus>(-1); */ /* thread has already been started */

    return 1;
}

static void    AudioFileManager_Disconnect (AudioFileManager *afm)
{
    if (afm->mIsEngaged)
    {
        sReaderThread->RemoveReader (sReaderThread, afm);
        afm->mIsEngaged = 0;
    }
}

static OSStatus AudioFileManager_Read(AudioFileManager *afm, char *buffer, UInt32 *len)
{
    return FSReadFork (afm->mForkRefNum,
                       fsFromStart,
                       afm->mReadFilePosition + afm->mAudioDataOffset,
                       *len,
                       buffer,
                       len);
}

static OSStatus AudioFileManager_GetFileData (AudioFileManager *afm, void** inOutData, UInt32 *inOutDataSize)
{
    if (afm->mFinishedReadingData)
    {
        ++afm->mNumTimesAskedSinceFinished;
        *inOutDataSize = 0;
        *inOutData = 0;
        return noErr;
    }
    
    if (afm->mReadFromFirstBuffer == afm->mWriteToFirstBuffer) {
        #if DEBUG
        printf ("* * * * * * * Can't keep up with reading file\n");
        #endif
        
        afm->mParent->DoNotification (afm->mParent, kAudioFilePlayErr_FilePlayUnderrun);
        *inOutDataSize = 0;
        *inOutData = 0;
    } else {
        *inOutDataSize = afm->mChunkSize;
        *inOutData = afm->mReadFromFirstBuffer ? afm->mFileBuffer : (afm->mFileBuffer + afm->mChunkSize);
    }

    afm->mLockUnsuccessful = !sReaderThread->TryNextRead (sReaderThread, afm);
    
    afm->mReadFromFirstBuffer = !afm->mReadFromFirstBuffer;

    return noErr;
}

static void    AudioFileManager_AfterRender (AudioFileManager *afm)
{
    if (afm->mNumTimesAskedSinceFinished > 0)
    {
        int didLock = 0;
        SDLOSXCAGuard *guard = sReaderThread->GetGuard(sReaderThread);
        if (guard->Try(guard, &didLock)) {
            afm->mParent->DoNotification (afm->mParent, kAudioFilePlay_FileIsFinished);
            if (didLock)
                guard->Unlock(guard);
        }
    }

    if (afm->mLockUnsuccessful)
        afm->mLockUnsuccessful = !sReaderThread->TryNextRead (sReaderThread, afm);
}

static void    AudioFileManager_SetPosition (AudioFileManager *afm, SInt64 pos)
{
    if (pos < 0 || pos >= afm->mFileLength) {
        SDL_SetError ("AudioFileManager::SetPosition - position invalid: %d filelen=%d\n", 
            (unsigned int)pos, (unsigned int)afm->mFileLength);
        pos = 0;
    }
        
    afm->mReadFilePosition = pos;
}
    
static void    AudioFileManager_SetEndOfFile (AudioFileManager *afm, SInt64 pos)
{
    if (pos <= 0 || pos > afm->mFileLength) {
        SDL_SetError ("AudioFileManager::SetEndOfFile - position beyond actual eof\n");
        pos = afm->mFileLength;
    }
    
    afm->mFileLength = pos;
}

static const char *AudioFileManager_GetFileBuffer(AudioFileManager *afm)
{
    return afm->mFileBuffer;
}

const AudioFilePlayer *AudioFileManager_GetParent(AudioFileManager *afm)
{
    return afm->mParent;
}

static int AudioFileManager_GetByteCounter(AudioFileManager *afm)
{
    return afm->mByteCounter;
}


static OSStatus    AudioFileManager_FileInputProc (void                       *inRefCon,
                                             AudioUnitRenderActionFlags inActionFlags,
                                             const AudioTimeStamp       *inTimeStamp, 
                                             UInt32                     inBusNumber, 
                                             AudioBuffer                *ioData)
{
    AudioFileManager* afm = (AudioFileManager*)inRefCon;
    return afm->Render(afm, ioData);
}

static OSStatus    AudioFileManager_Render (AudioFileManager *afm, AudioBuffer *ioData)
{
    OSStatus result = noErr;
    
	if (afm->mBufferOffset >= afm->mBufferSize) {
		result = afm->GetFileData(afm, &afm->mTmpBuffer, &afm->mBufferSize);
		if (result) {
			SDL_SetError ("AudioConverterFillBuffer:%ld\n", result);
			afm->mParent->DoNotification(afm->mParent, result);
			return result;
		}

		afm->mBufferOffset = 0;
	}
    	
    if (ioData->mDataByteSize > afm->mBufferSize - afm->mBufferOffset)
    	ioData->mDataByteSize = afm->mBufferSize - afm->mBufferOffset;
    ioData->mData = (char *)afm->mTmpBuffer + afm->mBufferOffset;
    afm->mBufferOffset += ioData->mDataByteSize;
    
	afm->mByteCounter += ioData->mDataByteSize;
	afm->AfterRender(afm);
    return result;
}


void delete_AudioFileManager (AudioFileManager *afm)
{
    if (afm != NULL) {
        if (afm->mFileBuffer) {
            free(afm->mFileBuffer);
        }

        SDL_free(afm);
    }
}


AudioFileManager *new_AudioFileManager(AudioFilePlayer *inParent,
                                       SInt16          inForkRefNum,
                                       SInt64          inFileLength,
                                       UInt32          inChunkSize)
{
    AudioFileManager *afm;

    if (sReaderThread == NULL)
    {
        sReaderThread = new_FileReaderThread();
        if (sReaderThread == NULL)
            return NULL;
    }

    afm = (AudioFileManager *) SDL_malloc(sizeof (AudioFileManager));
    if (afm == NULL)
        return NULL;
    SDL_memset(afm, '\0', sizeof (*afm));

    #define SET_AUDIOFILEMANAGER_METHOD(m) afm->m = AudioFileManager_##m
    SET_AUDIOFILEMANAGER_METHOD(Disconnect);
    SET_AUDIOFILEMANAGER_METHOD(DoConnect);
    SET_AUDIOFILEMANAGER_METHOD(Read);
    SET_AUDIOFILEMANAGER_METHOD(GetFileBuffer);
    SET_AUDIOFILEMANAGER_METHOD(GetParent);
    SET_AUDIOFILEMANAGER_METHOD(SetPosition);
    SET_AUDIOFILEMANAGER_METHOD(GetByteCounter);
    SET_AUDIOFILEMANAGER_METHOD(SetEndOfFile);
    SET_AUDIOFILEMANAGER_METHOD(Render);
    SET_AUDIOFILEMANAGER_METHOD(GetFileData);
    SET_AUDIOFILEMANAGER_METHOD(AfterRender);
    SET_AUDIOFILEMANAGER_METHOD(FileInputProc);
    #undef SET_AUDIOFILEMANAGER_METHOD

    afm->mParent = inParent;
    afm->mForkRefNum = inForkRefNum;
    afm->mBufferSize = inChunkSize;
    afm->mBufferOffset = inChunkSize;
    afm->mChunkSize = inChunkSize;
    afm->mFileLength = inFileLength;
    afm->mFileBuffer = (char*) SDL_malloc(afm->mChunkSize * 2);
    FSGetForkPosition(afm->mForkRefNum, &afm->mAudioDataOffset);
    assert (afm->mFileBuffer != NULL);
    return afm;
}