// Resets the internal mck pointer so reading starts from the beginning of the file again
public unsafe int ResetFile()
{
if (mbIsReadingFromMemory)
{
mpbDataCur = 0;
}
else
{
if (mhmmio == null)
{
return(-1);
}
// Seek to the data
if (mhmmio.Seek(mckRiff.dwDataOffset + sizeof(int), FS_SEEK.SET) == -1)
{
return(-1);
}
// Search the input file for for the 'fmt ' chunk.
mck.ckid = 0;
do
{
byte ioin;
if (mhmmio.Read(&ioin, 1) == 0)
{
return(-1);
}
mck.ckid = (mck.ckid >> 8) | (ioin << 24);
} while (mck.ckid != SoundSystemLocal.mmioFOURCC('d', 'a', 't', 'a'));
uint mck_cksize;
mhmmio.Read((byte *)&mck_cksize, 4);
Debug.Assert(!isOgg);
mck.cksize = LittleUInt(mck_cksize);
mseekBase = mhmmio.Tell;
}
return(0);
}
// Support function for reading from a multimedia I/O stream. mhmmio must be valid before calling. This function uses it to update mckRiff, and mpwfx.
unsafe int ReadMMIO()
{
Mminfo ckIn; // chunk info. for general use.
PcmWaveFormat pcmWaveFormat; // Temp PCM structure to load in.
mpwfx = default;
fixed(void *mckRiff_ = &mckRiff) mhmmio.Read((byte *)mckRiff_, 12);
Debug.Assert(!isOgg);
mckRiff.ckid = LittleInt(mckRiff.ckid);
mckRiff.cksize = LittleUInt(mckRiff.cksize);
mckRiff.fccType = LittleInt(mckRiff.fccType);
mckRiff.dwDataOffset = 12;
// Check to make sure this is a valid wave file
if (mckRiff.ckid != SoundSystemLocal.fourcc_riff || mckRiff.fccType != SoundSystemLocal.mmioFOURCC('W', 'A', 'V', 'E'))
{
return(-1);
}
// Search the input file for for the 'fmt ' chunk.
ckIn.dwDataOffset = 12;
do
{
if (mhmmio.Read((byte *)&ckIn, 8) != 8)
{
return(-1);
}
Debug.Assert(!isOgg);
ckIn.ckid = LittleInt(ckIn.ckid);
ckIn.cksize = LittleUInt(ckIn.cksize);
ckIn.dwDataOffset += (int)(ckIn.cksize - 8);
} while (ckIn.ckid != SoundSystemLocal.mmioFOURCC('f', 'm', 't', ' '));
// Expect the 'fmt' chunk to be at least as large as <PCMWAVEFORMAT>; if there are extra parameters at the end, we'll ignore them
if (ckIn.cksize < sizeof(PcmWaveFormat))
{
return(-1);
}
// Read the 'fmt ' chunk into <pcmWaveFormat>.
if (mhmmio.Read((byte *)&pcmWaveFormat, sizeof(PcmWaveFormat)) != sizeof(PcmWaveFormat))
{
return(-1);
}
Debug.Assert(!isOgg);
pcmWaveFormat.wf.wFormatTag = (WAVE_FORMAT_TAG)LittleShort((short)pcmWaveFormat.wf.wFormatTag);
pcmWaveFormat.wf.nChannels = LittleShort(pcmWaveFormat.wf.nChannels);
pcmWaveFormat.wf.nSamplesPerSec = LittleInt(pcmWaveFormat.wf.nSamplesPerSec);
pcmWaveFormat.wf.nAvgBytesPerSec = LittleInt(pcmWaveFormat.wf.nAvgBytesPerSec);
pcmWaveFormat.wf.nBlockAlign = LittleShort(pcmWaveFormat.wf.nBlockAlign);
pcmWaveFormat.wBitsPerSample = LittleShort(pcmWaveFormat.wBitsPerSample);
// Copy the bytes from the pcm structure to the waveformatex_t structure
mpwfx.memcpy(ref pcmWaveFormat);
// Allocate the waveformatex_t, but if its not pcm format, read the next word, and thats how many extra bytes to allocate.
if (pcmWaveFormat.wf.wFormatTag == WAVE_FORMAT_TAG.PCM)
{
mpwfx.Format.cbSize = 0;
}
else
{
return(-1); // we don't handle these (32 bit wavefiles, etc)
#if false
// Read in length of extra bytes.
word cbExtraBytes = 0L;
if (mhmmio.Read((char *)&cbExtraBytes, sizeof(word)) != sizeof(word))
{
return(-1);
}
mpwfx.Format.cbSize = cbExtraBytes;
// Now, read those extra bytes into the structure, if cbExtraAlloc != 0.
if (mhmmio.Read((char *)(((byte *)&(mpwfx.Format.cbSize)) + sizeof(word)), cbExtraBytes) != cbExtraBytes)
{
memset(&mpwfx, 0, sizeof(waveformatextensible_t)); return(-1);
}
#endif
}
return(0);
}
