int CWAVInputSource::AnalyzeSource()
{
unsigned char *p = FULL_HEADER, *priff = NULL;
// seek to the beginning (just in case)
m_spIO->Seek(0, FILE_BEGIN);
// get the file size
m_nFileBytes = m_spIO->GetSize();
// get the RIFF header
RETURN_ON_ERROR(ReadSafe(m_spIO, p, sizeof(RIFF_HEADER)))
// make sure the RIFF header is valid
if (!(p[0] == 'R' && p[1] == 'I' && p[2] == 'F' && p[3] == 'F'))
return ERROR_INVALID_INPUT_FILE;
p += sizeof(RIFF_HEADER);
// read the data type header
RETURN_ON_ERROR(ReadSafe(m_spIO, p, sizeof(DATA_TYPE_ID_HEADER)))
// make sure it's the right data type
if (!(p[0] == 'W' && p[1] == 'A' && p[2] == 'V' && p[3] == 'E'))
return ERROR_INVALID_INPUT_FILE;
p += sizeof(DATA_TYPE_ID_HEADER);
// find the 'fmt ' chunk
RETURN_ON_ERROR(ReadSafe(m_spIO, p, sizeof(RIFF_CHUNK_HEADER)))
while (!(p[0] == 'f' && p[1] == 'm' && p[2] == 't' && p[3] == ' '))
{
p += sizeof(RIFF_CHUNK_HEADER);
// move the file pointer to the end of this chunk
RETURN_ON_ERROR(ReadSafe(m_spIO, p, LE_LONG(p+4)))
p += LE_LONG(p+4);
// check again for the data chunk
RETURN_ON_ERROR(ReadSafe(m_spIO, p, sizeof(RIFF_CHUNK_HEADER)))
}
priff = p+4;
p += sizeof(RIFF_CHUNK_HEADER);
// read the format info
RETURN_ON_ERROR(ReadSafe(m_spIO, p, sizeof(WAV_FORMAT_HEADER)))
// error check the header to see if we support it
if (LE_SHORT(p) != 1)
return ERROR_INVALID_INPUT_FILE;
// copy the format information to the WAVEFORMATEX passed in
FillWaveFormatEx(&m_wfeSource, LE_LONG(p+4), LE_SHORT(p+14), LE_SHORT(p+2));
p += sizeof(WAV_FORMAT_HEADER);
// skip over any extra data in the header
int nWAVFormatHeaderExtra = LE_LONG(priff) - sizeof(WAV_FORMAT_HEADER);
if (nWAVFormatHeaderExtra < 0)
return ERROR_INVALID_INPUT_FILE;
else {
RETURN_ON_ERROR(ReadSafe(m_spIO, p, nWAVFormatHeaderExtra))
p += nWAVFormatHeaderExtra;
}
// find the data chunk
RETURN_ON_ERROR(ReadSafe(m_spIO, p, sizeof(RIFF_CHUNK_HEADER)))
while (!(p[0] == 'd' && p[1] == 'a' && p[2] == 't' && p[3] == 'a'))
{
p += sizeof(RIFF_CHUNK_HEADER);
// move the file pointer to the end of this chunk
RETURN_ON_ERROR(ReadSafe(m_spIO, p, LE_LONG(p+4)))
p += LE_LONG(p+4);
// check again for the data chunk
RETURN_ON_ERROR(ReadSafe(m_spIO, p, sizeof(RIFF_CHUNK_HEADER)))
}
// we're at the data block
m_nDataBytes = LE_LONG(p+4);
if (m_nDataBytes < 0)
m_nDataBytes = m_nFileBytes - m_nHeaderBytes;
p += sizeof(RIFF_CHUNK_HEADER);
m_nHeaderBytes = p - FULL_HEADER;
// make sure the data bytes is a whole number of blocks
if ((m_nDataBytes % m_wfeSource.nBlockAlign) != 0)
return ERROR_INVALID_INPUT_FILE;
// calculate the terminating byts
m_nTerminatingBytes = 0;
// we made it this far, everything must be cool
return ERROR_SUCCESS;
}
int CWAVInputSource::AnalyzeSource()
{
// seek to the beginning (just in case)
m_spIO->Seek(0, FILE_BEGIN);
// get the file size
m_nFileBytes = m_spIO->GetSize();
// get the RIFF header
RIFF_HEADER RIFFHeader;
RETURN_ON_ERROR(ReadSafe(m_spIO, &RIFFHeader, sizeof(RIFFHeader)))
// make sure the RIFF header is valid
if (!(RIFFHeader.cRIFF[0] == 'R' && RIFFHeader.cRIFF[1] == 'I' && RIFFHeader.cRIFF[2] == 'F' && RIFFHeader.cRIFF[3] == 'F'))
return ERROR_INVALID_INPUT_FILE;
// read the data type header
DATA_TYPE_ID_HEADER DataTypeIDHeader;
RETURN_ON_ERROR(ReadSafe(m_spIO, &DataTypeIDHeader, sizeof(DataTypeIDHeader)))
// make sure it's the right data type
if (!(DataTypeIDHeader.cDataTypeID[0] == 'W' && DataTypeIDHeader.cDataTypeID[1] == 'A' && DataTypeIDHeader.cDataTypeID[2] == 'V' && DataTypeIDHeader.cDataTypeID[3] == 'E'))
return ERROR_INVALID_INPUT_FILE;
// find the 'fmt ' chunk
RIFF_CHUNK_HEADER RIFFChunkHeader;
RETURN_ON_ERROR(ReadSafe(m_spIO, &RIFFChunkHeader, sizeof(RIFFChunkHeader)))
while (!(RIFFChunkHeader.cChunkLabel[0] == 'f' && RIFFChunkHeader.cChunkLabel[1] == 'm' && RIFFChunkHeader.cChunkLabel[2] == 't' && RIFFChunkHeader.cChunkLabel[3] == ' '))
{
// move the file pointer to the end of this chunk
m_spIO->Seek(RIFFChunkHeader.nChunkBytes, FILE_CURRENT);
// check again for the data chunk
RETURN_ON_ERROR(ReadSafe(m_spIO, &RIFFChunkHeader, sizeof(RIFFChunkHeader)))
}
// read the format info
WAV_FORMAT_HEADER WAVFormatHeader;
RETURN_ON_ERROR(ReadSafe(m_spIO, &WAVFormatHeader, sizeof(WAVFormatHeader)))
// error check the header to see if we support it
if (WAVFormatHeader.nFormatTag != 1)
return ERROR_INVALID_INPUT_FILE;
// copy the format information to the WAVEFORMATEX passed in
FillWaveFormatEx(&m_wfeSource, WAVFormatHeader.nSamplesPerSecond, WAVFormatHeader.nBitsPerSample, WAVFormatHeader.nChannels);
// skip over any extra data in the header
int nWAVFormatHeaderExtra = RIFFChunkHeader.nChunkBytes - sizeof(WAVFormatHeader);
if (nWAVFormatHeaderExtra < 0)
return ERROR_INVALID_INPUT_FILE;
else
m_spIO->Seek(nWAVFormatHeaderExtra, FILE_CURRENT);
// find the data chunk
RETURN_ON_ERROR(ReadSafe(m_spIO, &RIFFChunkHeader, sizeof(RIFFChunkHeader)))
while (!(RIFFChunkHeader.cChunkLabel[0] == 'd' && RIFFChunkHeader.cChunkLabel[1] == 'a' && RIFFChunkHeader.cChunkLabel[2] == 't' && RIFFChunkHeader.cChunkLabel[3] == 'a'))
{
// move the file pointer to the end of this chunk
m_spIO->Seek(RIFFChunkHeader.nChunkBytes, FILE_CURRENT);
// check again for the data chunk
RETURN_ON_ERROR(ReadSafe(m_spIO, &RIFFChunkHeader, sizeof(RIFFChunkHeader)))
}
// we're at the data block
m_nHeaderBytes = m_spIO->GetPosition();
m_nDataBytes = RIFFChunkHeader.nChunkBytes;
if (m_nDataBytes < 0)
m_nDataBytes = m_nFileBytes - m_nHeaderBytes;
// make sure the data bytes is a whole number of blocks
if ((m_nDataBytes % m_wfeSource.nBlockAlign) != 0)
return ERROR_INVALID_INPUT_FILE;
// calculate the terminating byts
m_nTerminatingBytes = m_nFileBytes - m_nDataBytes - m_nHeaderBytes;
// we made it this far, everything must be cool
return ERROR_SUCCESS;
}
