mythogen

static void HandleOutputBuffer(void* userInfo,
                               AudioQueueRef queue,
                               AudioQueueBufferRef buffer) {
    NSAutoreleasePool* pool = [[NSAutoreleasePool alloc] init];
    TapeRecorder* recorder = (TapeRecorder*)userInfo;
    if(![recorder isPlaying]) {
        return;
    }
    NSData* samples = [[recorder tape] getSamplesOfCount:[recorder mBufferByteSize]/2 atSampleOffset:[recorder mCurrentPacket]];
    if(samples != nil) {
        [samples getBytes:buffer->mAudioData length:[samples length]];
        buffer->mAudioDataByteSize = [samples length];
        OSStatus stat = AudioQueueEnqueueBuffer(queue, buffer, 0, NULL);
        //[recorder ReportAudioError:stat];
        [recorder setMCurrentPacket:[recorder mCurrentPacket]+[samples length]/2];
        if([samples length] < [recorder mBufferByteSize]) {
            AudioQueueStop(queue, false);
        }
    }
    else {
        AudioQueueStop(queue, false);
        //error
    }
    [pool release];
}

- (void)startPlaying {
    if(playingAvailable) {
        NSError* error;
        [session setCategory:AVAudioSessionCategoryPlayback error:nil];
        [session setActive:YES error:&error];
        if(error) {
            NSLog([error description]);
        }

        mBufferByteSize = 11025*2; //one second buffer size

        mStreamDescription.mBitsPerChannel = 16;
        mStreamDescription.mSampleRate = SAMPLE_RATE;
        mStreamDescription.mChannelsPerFrame = 1;
        mStreamDescription.mFormatID = kAudioFormatLinearPCM;
        mStreamDescription.mFramesPerPacket = 1;
        mStreamDescription.mBytesPerFrame = mStreamDescription.mBytesPerPacket = 2;
        mStreamDescription.mFormatFlags = kLinearPCMFormatFlagIsSignedInteger | kLinearPCMFormatFlagIsBigEndian | kLinearPCMFormatFlagIsPacked;

        OSStatus stat = AudioQueueNewOutput(&mStreamDescription, HandleOutputBuffer, self, NULL, kCFRunLoopCommonModes, 0, &mQueue);
        [self ReportAudioError:stat];
        if(mCurrentPacket > .99*[tape totalSamples]) {
            mCurrentPacket = 0; //reset to start
            self.timeIndexInSeconds = 0;
        }
        self.state = RecorderStatePlaying;

        for(int i = 0; i < NUM_BUFFERS; i++) {
            AudioQueueAllocateBuffer(mQueue, mBufferByteSize, &mPlaybackBuffers[i]);
            HandleOutputBuffer(self, mQueue, mPlaybackBuffers[i]);
        }
        AudioQueueAddPropertyListener(mQueue, kAudioQueueProperty_IsRunning, QueuePropertyListener, self);
        AudioQueueStart(mQueue, NULL);
        timer = [[NSTimer scheduledTimerWithTimeInterval:1.0 target:self selector:@selector(timerFired:) userInfo:@"play" repeats:YES] retain];
    }
}