scummvm/sound/midiparser_smf.cpp

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/* ScummVM - Graphic Adventure Engine
*
* ScummVM is the legal property of its developers, whose names
* are too numerous to list here. Please refer to the COPYRIGHT
* file distributed with this source distribution.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*
* $URL$
* $Id$
*
*/
#include "sound/midiparser.h"
#include "sound/mididrv.h"
#include "common/util.h"
/**
* The Standard MIDI File version of MidiParser.
*/
class MidiParser_SMF : public MidiParser {
protected:
byte *_buffer;
bool _malformedPitchBends;
protected:
void compressToType0();
void parseNextEvent(EventInfo &info);
public:
MidiParser_SMF() : _buffer(0), _malformedPitchBends(false) {}
~MidiParser_SMF();
bool loadMusic(byte *data, uint32 size);
void property(int property, int value);
};
static const byte command_lengths[8] = { 3, 3, 3, 3, 2, 2, 3, 0 };
static const byte special_lengths[16] = { 0, 2, 3, 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0 };
MidiParser_SMF::~MidiParser_SMF() {
free(_buffer);
}
void MidiParser_SMF::property(int prop, int value) {
switch (prop) {
case mpMalformedPitchBends:
_malformedPitchBends = (value > 0);
default:
MidiParser::property(prop, value);
}
}
void MidiParser_SMF::parseNextEvent(EventInfo &info) {
info.start = _position._play_pos;
info.delta = readVLQ(_position._play_pos);
// Process the next info. If mpMalformedPitchBends
// was set, we must skip over any pitch bend events
// because they are from Simon games and are not
// real pitch bend events, they're just two-byte
// prefixes before the real info.
do {
if ((_position._play_pos[0] & 0xF0) >= 0x80)
info.event = *(_position._play_pos++);
else
info.event = _position._running_status;
} while (_malformedPitchBends && (info.event & 0xF0) == 0xE0 && _position._play_pos++);
if (info.event < 0x80)
return;
_position._running_status = info.event;
switch (info.command()) {
case 0x9: // Note On
info.basic.param1 = *(_position._play_pos++);
info.basic.param2 = *(_position._play_pos++);
if (info.basic.param2 == 0)
info.event = info.channel() | 0x80;
info.length = 0;
break;
case 0xC:
case 0xD:
info.basic.param1 = *(_position._play_pos++);
info.basic.param2 = 0;
break;
case 0x8:
case 0xA:
case 0xB:
case 0xE:
info.basic.param1 = *(_position._play_pos++);
info.basic.param2 = *(_position._play_pos++);
info.length = 0;
break;
case 0xF: // System Common, Meta or SysEx event
switch (info.event & 0x0F) {
case 0x2: // Song Position Pointer
info.basic.param1 = *(_position._play_pos++);
info.basic.param2 = *(_position._play_pos++);
break;
case 0x3: // Song Select
info.basic.param1 = *(_position._play_pos++);
info.basic.param2 = 0;
break;
case 0x6:
case 0x8:
case 0xA:
case 0xB:
case 0xC:
case 0xE:
info.basic.param1 = info.basic.param2 = 0;
break;
case 0x0: // SysEx
info.length = readVLQ(_position._play_pos);
info.ext.data = _position._play_pos;
_position._play_pos += info.length;
break;
case 0xF: // META event
info.ext.type = *(_position._play_pos++);
info.length = readVLQ(_position._play_pos);
info.ext.data = _position._play_pos;
_position._play_pos += info.length;
break;
default:
warning("MidiParser_SMF::parseNextEvent: Unsupported event code %x", info.event);
}
}
}
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.
2010-07-16 03:31:45 +00:00
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;
}
void MidiParser_SMF::compressToType0() {
// We assume that _buffer has been allocated
// to sufficient size for this operation.
// using 0xFF since it could write track_pos[0 to _num_tracks] here
// this would cause some illegal writes and could lead to segfaults
// (it crashed for some midis for me, they're not used in any game
// scummvm supports though). *Maybe* handle this in another way,
// it's at the moment only to be sure, that nothing goes wrong.
byte *track_pos[0xFF];
byte running_status[0xFF];
uint32 track_timer[0xFF];
uint32 delta;
int i;
for (i = 0; i < _num_tracks; ++i) {
running_status[i] = 0;
track_pos[i] = _tracks[i];
track_timer[i] = readVLQ(track_pos[i]);
running_status[i] = 0;
}
int best_i;
uint32 length;
byte *output = _buffer;
byte *pos, *pos2;
byte event;
uint32 copy_bytes;
bool write;
byte active_tracks = (byte)_num_tracks;
while (active_tracks) {
write = true;
best_i = 255;
for (i = 0; i < _num_tracks; ++i) {
if (track_pos[i] && (best_i == 255 || track_timer[i] < track_timer[best_i]))
best_i = i;
}
if (best_i == 255) {
warning("Premature end of tracks");
break;
}
// Initial VLQ delta computation
delta = 0;
length = track_timer[best_i];
for (i = 0; length; ++i) {
delta = (delta << 8) | (length & 0x7F) | (i ? 0x80 : 0);
length >>= 7;
}
// Process MIDI event.
bool implicitEvent = false;
copy_bytes = 0;
pos = track_pos[best_i];
do {
event = *(pos++);
if (event < 0x80) {
event = running_status[best_i];
implicitEvent = true;
}
} while (_malformedPitchBends && (event & 0xF0) == 0xE0 && pos++);
running_status[best_i] = event;
if (command_lengths[(event >> 4) - 8] > 0) {
copy_bytes = command_lengths[(event >> 4) - 8];
} else if (special_lengths[(event & 0x0F)] > 0) {
copy_bytes = special_lengths[(event & 0x0F)];
} else if (event == 0xF0) {
// SysEx
pos2 = pos;
length = readVLQ(pos);
copy_bytes = 1 + (pos - pos2) + length;
} else if (event == 0xFF) {
// META
event = *(pos++);
if (event == 0x2F && active_tracks > 1) {
track_pos[best_i] = 0;
write = false;
} else {
pos2 = pos;
length = readVLQ(pos);
copy_bytes = 2 + (pos - pos2) + length;
}
if (event == 0x2F)
--active_tracks;
} else {
warning("Bad MIDI command %02X", (int)event);
track_pos[best_i] = 0;
}
// Update all tracks' deltas
if (write) {
for (i = 0; i < _num_tracks; ++i) {
if (track_pos[i] && i != best_i)
track_timer[i] -= track_timer[best_i];
}
}
if (track_pos[best_i]) {
if (write) {
track_timer[best_i] = 0;
// Write VLQ delta
while (delta & 0x80) {
*output++ = (byte)(delta & 0xFF);
delta >>= 8;
}
*output++ = (byte)(delta & 0xFF);
// Write MIDI data
if (!implicitEvent)
++track_pos[best_i];
--copy_bytes;
*output++ = running_status[best_i];
memcpy(output, track_pos[best_i], copy_bytes);
output += copy_bytes;
}
// Fetch new VLQ delta for winning track
track_pos[best_i] += copy_bytes;
if (active_tracks)
track_timer[best_i] += readVLQ(track_pos[best_i]);
}
}
*output++ = 0x00;
}
MidiParser *MidiParser::createParser_SMF() { return new MidiParser_SMF; }