XMISong::XMISong (FileReader &reader, EMidiDevice type, const char *args)
: MIDIStreamer(type, args), MusHeader(0), Songs(0)
{
SongLen = reader.GetLength();
MusHeader = new uint8_t[SongLen];
if (reader.Read(MusHeader, SongLen) != SongLen)
return;
// Find all the songs in this file.
NumSongs = FindXMIDforms(MusHeader, SongLen, NULL);
if (NumSongs == 0)
{
return;
}
// XMIDI files are played with a constant 120 Hz clock rate. While the
// song may contain tempo events, these are vestigial remnants from the
// original MIDI file that were not removed by the converter and should
// be ignored.
//
// We can use any combination of Division and Tempo values that work out
// to be 120 Hz.
Division = 60;
InitialTempo = 500000;
Songs = new TrackInfo[NumSongs];
memset(Songs, 0, sizeof(*Songs) * NumSongs);
FindXMIDforms(MusHeader, SongLen, Songs);
CurrSong = Songs;
DPrintf(DMSG_SPAMMY, "XMI song count: %d\n", NumSongs);
}
int XMISong::FindXMIDforms(const BYTE *chunk, int len, TrackInfo *songs) const
{
int count = 0;
for (int p = 0; p <= len - 12; )
{
int chunktype = GetNativeInt(chunk + p);
int chunklen = GetBigInt(chunk + p + 4);
if (chunktype == MAKE_ID('F','O','R','M'))
{
if (GetNativeInt(chunk + p + 8) == MAKE_ID('X','M','I','D'))
{
if (songs != NULL)
{
FoundXMID(chunk + p + 12, chunklen - 4, songs + count);
}
count++;
}
}
else if (chunktype == MAKE_ID('C','A','T',' '))
{
// Recurse to handle CAT chunks.
count += FindXMIDforms(chunk + p + 12, chunklen - 4, songs + count);
}
// IFF chunks are padded to even byte boundaries to avoid
// unaligned reads on 68k processors.
p += 8 + chunklen + (chunklen & 1);
// Avoid crashes from corrupt chunks which indicate a negative size.
if (chunklen < 0) p = len;
}
return count;
}
XMISong::XMISong (FILE *file, BYTE *musiccache, int len, EMidiDevice type)
: MIDIStreamer(type), MusHeader(0), Songs(0)
{
#ifdef _WIN32
if (ExitEvent == NULL)
{
return;
}
#endif
MusHeader = new BYTE[len];
SongLen = len;
if (file != NULL)
{
if (fread(MusHeader, 1, len, file) != (size_t)len)
return;
}
else
{
memcpy(MusHeader, musiccache, len);
}
// Find all the songs in this file.
NumSongs = FindXMIDforms(MusHeader, len, NULL);
if (NumSongs == 0)
{
return;
}
// XMIDI files are played with a constant 120 Hz clock rate. While the
// song may contain tempo events, these are vestigial remnants from the
// original MIDI file that were not removed by the converter and should
// be ignored.
//
// We can use any combination of Division and Tempo values that work out
// to be 120 Hz.
Division = 60;
InitialTempo = 500000;
Songs = new TrackInfo[NumSongs];
memset(Songs, 0, sizeof(*Songs) * NumSongs);
FindXMIDforms(MusHeader, len, Songs);
CurrSong = Songs;
DPrintf("XMI song count: %d\n", NumSongs);
}
