bool QWaveDecoder::findChunk(const char *chunkId)
{
chunk descriptor;
do {
if (!peekChunk(&descriptor))
return false;
if (qstrncmp(descriptor.id, chunkId, 4) == 0)
return true;
// It's possible that bytes->available() is less than the chunk size
// if it's corrupt.
junkToSkip = qint64(sizeof(chunk) + descriptor.size);
// Skip the current amount
if (junkToSkip > 0)
discardBytes(junkToSkip);
// If we still have stuff left, just exit and try again later
// since we can't call peekChunk
if (junkToSkip > 0)
return false;
} while (source->bytesAvailable() > 0);
return false;
}
bool QWaveDecoder::findChunk(const char *chunkId)
{
if (source->bytesAvailable() < qint64(sizeof(chunk)))
return false;
chunk descriptor;
source->peek(reinterpret_cast<char *>(&descriptor), sizeof(chunk));
if (qstrncmp(descriptor.id, chunkId, 4) == 0)
return true;
while (source->bytesAvailable() >= qint64(sizeof(chunk) + descriptor.size)) {
discardBytes(sizeof(chunk) + descriptor.size);
source->peek(reinterpret_cast<char *>(&descriptor), sizeof(chunk));
if (qstrncmp(descriptor.id, chunkId, 4) == 0)
return true;
}
return false;
}
void QWaveDecoder::handleData()
{
// As a special "state", if we have junk to skip, we do
if (junkToSkip > 0) {
discardBytes(junkToSkip); // this also updates junkToSkip
// If we couldn't skip all the junk, return
if (junkToSkip > 0) {
// We might have run out
if (source->atEnd())
parsingFailed();
return;
}
}
if (state == QWaveDecoder::InitialState) {
if (source->bytesAvailable() < qint64(sizeof(RIFFHeader)))
return;
RIFFHeader riff;
source->read(reinterpret_cast<char *>(&riff), sizeof(RIFFHeader));
// RIFF = little endian RIFF, RIFX = big endian RIFF
if (((qstrncmp(riff.descriptor.id, "RIFF", 4) != 0) && (qstrncmp(riff.descriptor.id, "RIFX", 4) != 0))
|| qstrncmp(riff.type, "WAVE", 4) != 0) {
parsingFailed();
return;
} else {
state = QWaveDecoder::WaitingForFormatState;
if (qstrncmp(riff.descriptor.id, "RIFX", 4) == 0)
bigEndian = true;
else
bigEndian = false;
}
}
if (state == QWaveDecoder::WaitingForFormatState) {
if (findChunk("fmt ")) {
chunk descriptor;
peekChunk(&descriptor);
quint32 rawChunkSize = descriptor.size + sizeof(chunk);
if (source->bytesAvailable() < qint64(rawChunkSize))
return;
WAVEHeader wave;
source->read(reinterpret_cast<char *>(&wave), sizeof(WAVEHeader));
if (rawChunkSize > sizeof(WAVEHeader))
discardBytes(rawChunkSize - sizeof(WAVEHeader));
// Swizzle this
if (bigEndian) {
wave.audioFormat = qFromBigEndian<quint16>(wave.audioFormat);
} else {
wave.audioFormat = qFromLittleEndian<quint16>(wave.audioFormat);
}
if (wave.audioFormat != 0 && wave.audioFormat != 1) {
// 32bit wave files have format == 0xFFFE (WAVE_FORMAT_EXTENSIBLE).
// but don't support them at the moment.
parsingFailed();
return;
} else {
format.setCodec(QLatin1String("audio/pcm"));
if (bigEndian) {
int bps = qFromBigEndian<quint16>(wave.bitsPerSample);
format.setSampleType(bps == 8 ? QAudioFormat::UnSignedInt : QAudioFormat::SignedInt);
format.setByteOrder(QAudioFormat::BigEndian);
format.setSampleRate(qFromBigEndian<quint32>(wave.sampleRate));
format.setSampleSize(bps);
format.setChannelCount(qFromBigEndian<quint16>(wave.numChannels));
} else {
int bps = qFromLittleEndian<quint16>(wave.bitsPerSample);
format.setSampleType(bps == 8 ? QAudioFormat::UnSignedInt : QAudioFormat::SignedInt);
format.setByteOrder(QAudioFormat::LittleEndian);
format.setSampleRate(qFromLittleEndian<quint32>(wave.sampleRate));
format.setSampleSize(bps);
format.setChannelCount(qFromLittleEndian<quint16>(wave.numChannels));
}
state = QWaveDecoder::WaitingForDataState;
}
}
}
if (state == QWaveDecoder::WaitingForDataState) {
if (findChunk("data")) {
source->disconnect(SIGNAL(readyRead()), this, SLOT(handleData()));
chunk descriptor;
source->read(reinterpret_cast<char *>(&descriptor), sizeof(chunk));
if (bigEndian)
descriptor.size = qFromBigEndian<quint32>(descriptor.size);
else
descriptor.size = qFromLittleEndian<quint32>(descriptor.size);
dataSize = descriptor.size;
haveFormat = true;
connect(source, SIGNAL(readyRead()), SIGNAL(readyRead()));
emit formatKnown();
return;
}
}
// If we hit the end without finding data, it's a parsing error
if (source->atEnd()) {
parsingFailed();
}
}
void QWaveDecoder::handleData()
{
if (state == QWaveDecoder::InitialState) {
if (source->bytesAvailable() < qint64(sizeof(RIFFHeader)))
return;
RIFFHeader riff;
source->read(reinterpret_cast<char *>(&riff), sizeof(RIFFHeader));
if (qstrncmp(riff.descriptor.id, "RIFF", 4) != 0 ||
qstrncmp(riff.type, "WAVE", 4) != 0) {
source->disconnect(SIGNAL(readyRead()), this, SLOT(handleData()));
emit invalidFormat();
return;
} else {
state = QWaveDecoder::WaitingForFormatState;
}
}
if (state == QWaveDecoder::WaitingForFormatState) {
if (findChunk("fmt ")) {
chunk descriptor;
source->peek(reinterpret_cast<char *>(&descriptor), sizeof(chunk));
if (source->bytesAvailable() < qint64(descriptor.size + sizeof(chunk)))
return;
WAVEHeader wave;
source->read(reinterpret_cast<char *>(&wave), sizeof(WAVEHeader));
if (descriptor.size > sizeof(WAVEHeader))
discardBytes(descriptor.size - sizeof(WAVEHeader));
if (wave.audioFormat != 0 && wave.audioFormat != 1) {
source->disconnect(SIGNAL(readyRead()), this, SLOT(handleData()));
emit invalidFormat();
return;
} else {
int bps = qFromLittleEndian<quint16>(wave.bitsPerSample);
format.setCodec(QLatin1String("audio/pcm"));
format.setSampleType(bps == 8 ? QAudioFormat::UnSignedInt : QAudioFormat::SignedInt);
format.setByteOrder(QAudioFormat::LittleEndian);
format.setFrequency(qFromLittleEndian<quint32>(wave.sampleRate));
format.setSampleSize(bps);
format.setChannels(qFromLittleEndian<quint16>(wave.numChannels));
state = QWaveDecoder::WaitingForDataState;
}
}
}
if (state == QWaveDecoder::WaitingForDataState) {
if (findChunk("data")) {
source->disconnect(SIGNAL(readyRead()), this, SLOT(handleData()));
chunk descriptor;
source->read(reinterpret_cast<char *>(&descriptor), sizeof(chunk));
dataSize = descriptor.size;
haveFormat = true;
connect(source, SIGNAL(readyRead()), SIGNAL(readyRead()));
emit formatKnown();
return;
}
}
if (source->atEnd()) {
source->disconnect(SIGNAL(readyRead()), this, SLOT(handleData()));
emit invalidFormat();
return;
}
}
