bool FLACStream::seek(const Timestamp &where) {
_sampleCache.bufFill = 0;
_sampleCache.bufReadPos = NULL;
// FLAC uses the sample pair number, thus we always use "false" for the isStereo parameter
// of the convertTimeToStreamPos helper.
return seekAbsolute((FLAC__uint64)convertTimeToStreamPos(where, getRate(), false).totalNumberOfFrames());
}
int FlacInputStream::readBuffer(int16 *buffer, const int numSamples) {
const uint numChannels = getChannels();
if (numChannels == 0) {
warning("FlacInputStream: Stream not sucessfully initialised, cant playback");
return -1; // streaminfo wasnt read!
}
assert(numSamples % numChannels == 0); // must be multiple of channels!
assert(buffer != NULL);
assert(_outBuffer == NULL);
assert(_requestedSamples == 0);
_outBuffer = buffer;
_requestedSamples = numSamples;
// If there is still data in our buffer from the last time around,
// copy that first.
if (_sampleCache.bufFill > 0) {
assert(_sampleCache.bufReadPos >= _sampleCache.bufData);
assert(_sampleCache.bufFill % numChannels == 0);
const uint copySamples = MIN((uint)numSamples, _sampleCache.bufFill);
memcpy(buffer, _sampleCache.bufReadPos, copySamples*sizeof(buffer[0]));
_outBuffer = buffer + copySamples;
_requestedSamples = numSamples - copySamples;
_sampleCache.bufReadPos += copySamples;
_sampleCache.bufFill -= copySamples;
}
bool decoderOk = true;
FLAC__StreamDecoderState state = getStreamDecoderState();
// Keep poking FLAC to process more samples until we completely satisfied the request
// respectively until we run out of data.
while (!_lastSampleWritten && _requestedSamples > 0 && state == FLAC__STREAM_DECODER_SEARCH_FOR_FRAME_SYNC) {
assert(_sampleCache.bufFill == 0);
assert(_requestedSamples % numChannels == 0);
processSingleBlock();
state = getStreamDecoderState();
if (state == FLAC__STREAM_DECODER_END_OF_STREAM) {
_lastSampleWritten = true;
}
// If we reached the end of the stream, and looping is enabled: Try to rewind
if (_lastSampleWritten && _numLoops != 1) {
if (_numLoops != 0)
_numLoops--;
seekAbsolute(_firstSample);
state = getStreamDecoderState();
}
}
// Error handling
switch (state) {
case FLAC__STREAM_DECODER_END_OF_STREAM:
_lastSampleWritten = true;
break;
case FLAC__STREAM_DECODER_SEARCH_FOR_FRAME_SYNC:
break;
default:
decoderOk = false;
warning("FlacInputStream: An error occured while decoding. DecoderState is: %s",
FLAC__StreamDecoderStateString[getStreamDecoderState()]);
}
// Compute how many samples we actually produced
const int samples = (int)(_outBuffer - buffer);
assert(samples % numChannels == 0);
_outBuffer = NULL; // basically unnecessary, only for the purpose of the asserts
_requestedSamples = 0; // basically unnecessary, only for the purpose of the asserts
return decoderOk ? samples : -1;
}
