bool MidiParser_SMF::loadMusic(byte *data, uint32 size) {
uint32 len;
byte midi_type;
uint32 total_size;
bool isGMF;
unloadMusic();
byte *pos = data;
isGMF = false;
if (!memcmp(pos, "RIFF", 4)) {
// Skip the outer RIFF header.
pos += 8;
}
if (!memcmp(pos, "MThd", 4)) {
// SMF with MTHd information.
pos += 4;
len = read4high(pos);
if (len != 6) {
warning("MThd length 6 expected but found %d", (int)len);
return false;
}
// Verify that this MIDI either is a Type 2
// or has only 1 track. We do not support
// multitrack Type 1 files.
_num_tracks = pos[2] << 8 | pos[3];
midi_type = pos[1];
if (midi_type > 2 /*|| (midi_type < 2 && _num_tracks > 1)*/) {
warning("No support for a Type %d MIDI with %d tracks", (int)midi_type, (int)_num_tracks);
return false;
}
_ppqn = pos[4] << 8 | pos[5];
pos += len;
} else if (!memcmp(pos, "GMF\x1", 4)) {
// Older GMD/MUS file with no header info.
// Assume 1 track, 192 PPQN, and no MTrk headers.
isGMF = true;
midi_type = 0;
_num_tracks = 1;
_ppqn = 192;
pos += 7; // 'GMD\x1' + 3 bytes of useless (translate: unknown) information
} else {
warning("Expected MThd or GMD header but found '%c%c%c%c' instead", pos[0], pos[1], pos[2], pos[3]);
return false;
}
// Now we identify and store the location for each track.
if (_num_tracks > ARRAYSIZE(_tracks)) {
warning("Can only handle %d tracks but was handed %d", (int)ARRAYSIZE(_tracks), (int)_num_tracks);
return false;
}
total_size = 0;
int tracks_read = 0;
while (tracks_read < _num_tracks) {
if (memcmp(pos, "MTrk", 4) && !isGMF) {
warning("Position: %p ('%c')", pos, *pos);
warning("Hit invalid block '%c%c%c%c' while scanning for track locations", pos[0], pos[1], pos[2], pos[3]);
return false;
}
// If needed, skip the MTrk and length bytes
_tracks[tracks_read] = pos + (isGMF ? 0 : 8);
if (!isGMF) {
pos += 4;
len = read4high(pos);
total_size += len;
pos += len;
} else {
// An SMF End of Track meta event must be placed
// at the end of the stream.
data[size++] = 0xFF;
data[size++] = 0x2F;
data[size++] = 0x00;
data[size++] = 0x00;
}
++tracks_read;
}
// If this is a Type 1 MIDI, we need to now compress
// our tracks down into a single Type 0 track.
free(_buffer);
_buffer = 0;
if (midi_type == 1) {
// FIXME: Doubled the buffer size to prevent crashes with the
// Inherit the Earth MIDIs. Jamieson630 said something about a
// better fix, but this will have to do in the meantime.
_buffer = (byte *)malloc(size * 2);
compressToType0();
_num_tracks = 1;
_tracks[0] = _buffer;
}
// Note that we assume the original data passed in
// will persist beyond this call, i.e. we do NOT
// copy the data to our own buffer. Take warning....
resetTracking();
setTempo(500000);
setTrack(0);
return true;
}
bool MidiParser_XMIDI::loadMusic(byte *data, uint32 size) {
uint32 i = 0;
byte *start;
uint32 len;
uint32 chunk_len;
char buf[32];
_loopCount = -1;
unloadMusic();
byte *pos = data;
if (!memcmp(pos, "FORM", 4)) {
pos += 4;
// Read length of
len = read4high(pos);
start = pos;
// XDIRless XMIDI, we can handle them here.
if (!memcmp(pos, "XMID", 4)) {
warning("XMIDI doesn't have XDIR");
pos += 4;
_num_tracks = 1;
} else if (memcmp(pos, "XDIR", 4)) {
// Not an XMIDI that we recognise
warning("Expected 'XDIR' but found '%c%c%c%c'", pos[0], pos[1], pos[2], pos[3]);
return false;
} else {
// Seems Valid
pos += 4;
_num_tracks = 0;
for (i = 4; i < len; i++) {
// Read 4 bytes of type
memcpy(buf, pos, 4);
pos += 4;
// Read length of chunk
chunk_len = read4high(pos);
// Add eight bytes
i += 8;
if (memcmp(buf, "INFO", 4)) {
// Must align
pos += (chunk_len + 1) & ~1;
i += (chunk_len + 1) & ~1;
continue;
}
// Must be at least 2 bytes long
if (chunk_len < 2) {
warning("Invalid chunk length %d for 'INFO' block", (int)chunk_len);
return false;
}
_num_tracks = (byte)read2low(pos);
if (chunk_len > 2) {
warning("Chunk length %d is greater than 2", (int)chunk_len);
pos += chunk_len - 2;
}
break;
}
// Didn't get to fill the header
if (_num_tracks == 0) {
warning("Didn't find a valid track count");
return false;
}
// Ok now to start part 2
// Goto the right place
pos = start + ((len + 1) & ~1);
if (memcmp(pos, "CAT ", 4)) {
// Not an XMID
warning("Expected 'CAT ' but found '%c%c%c%c'", pos[0], pos[1], pos[2], pos[3]);
return false;
}
pos += 4;
// Now read length of this track
len = read4high(pos);
if (memcmp(pos, "XMID", 4)) {
// Not an XMID
warning("Expected 'XMID' but found '%c%c%c%c'", pos[0], pos[1], pos[2], pos[3]);
return false;
}
pos += 4;
}
// Ok it's an XMIDI.
// We're going to identify and store the location for each track.
if (_num_tracks > ARRAYSIZE(_tracks)) {
warning("Can only handle %d tracks but was handed %d", (int)ARRAYSIZE(_tracks), (int)_num_tracks);
return false;
}
int tracks_read = 0;
while (tracks_read < _num_tracks) {
if (!memcmp(pos, "FORM", 4)) {
// Skip this plus the 4 bytes after it.
pos += 8;
} else if (!memcmp(pos, "XMID", 4)) {
// Skip this.
pos += 4;
} else if (!memcmp(pos, "TIMB", 4)) {
// Custom timbres?
// We don't support them.
// Read the length, skip it, and hope there was nothing there.
pos += 4;
len = read4high(pos);
pos += (len + 1) & ~1;
} else if (!memcmp(pos, "EVNT", 4)) {
// Ahh! What we're looking for at last.
_tracks[tracks_read] = pos + 8; // Skip the EVNT and length bytes
pos += 4;
len = read4high(pos);
pos += (len + 1) & ~1;
++tracks_read;
} else {
warning("Hit invalid block '%c%c%c%c' while scanning for track locations", pos[0], pos[1], pos[2], pos[3]);
return false;
}
}
// If we got this far, we successfully established
// the locations for each of our tracks.
// Note that we assume the original data passed in
// will persist beyond this call, i.e. we do NOT
// copy the data to our own buffer. Take warning....
_ppqn = 60;
resetTracking();
setTempo(500000);
_inserted_delta = 0;
setTrack(0);
return true;
}
return false;
}
