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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 "common/util.h"
#include "sound/mididrv.h"
#include "sound/midiparser.h"
namespace AGOS {
/**
* Simon 1 Demo version of MidiParser.
*
* This parser is the result of eyeballing the one MUS file that's included
* with simon1demo. So there might be some things missing. I've tried to notate
* question-mark areas where they occur.
*/
class MidiParser_S1D : public MidiParser {
protected:
byte *_data;
bool _no_delta;
protected:
void parseNextEvent(EventInfo &info);
void resetTracking();
uint32 readVLQ2(byte * &data);
public:
MidiParser_S1D() : _data(0), _no_delta(false) {}
bool loadMusic(byte *data, uint32 size);
};
// The VLQs for simon1demo seem to be
// in Little Endian format.
uint32 MidiParser_S1D::readVLQ2(byte * &data) {
byte str;
uint32 value = 0;
int i;
for (i = 0; i < 4; ++i) {
str = data[0];
++data;
value |= (str & 0x7F) << (i * 7);
if (!(str & 0x80))
break;
}
return value;
}
void MidiParser_S1D::parseNextEvent(EventInfo &info) {
info.start = _position._play_pos;
info.delta = _no_delta ? 0 : readVLQ2(_position._play_pos);
_no_delta = false;
info.event = *(_position._play_pos++);
if (info.command() < 0x8) {
_no_delta = true;
info.event += 0x80;
}
switch (info.command()) {
case 0x8:
info.basic.param1 = *(_position._play_pos++);
info.basic.param2 = 0;
info.length = 0;
break;
case 0x9:
info.basic.param1 = *(_position._play_pos++);
info.basic.param2 = *(_position._play_pos++); // I'm ASSUMING this byte is velocity!
info.length = 0;
break;
case 0xA:
case 0xB:
// I'm not sure what these are meant to do, or what the
// parameter is. Elvira 1 needs them, though, and who am I to
// argue with her?
info.basic.param1 = *(_position._play_pos++);
info.basic.param2 = 0;
break;
case 0xC:
info.basic.param1 = *(_position._play_pos++);
info.basic.param2 = 0;
++_position._play_pos; // I have NO IDEA what the second byte is for.
break;
case 0xF:
if (info.event == 0xFC) {
// This means End of Track.
// Rewrite in SMF (MIDI transmission) form.
info.event = 0xFF;
info.ext.type = 0x2F;
info.length = 0;
break;
}
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 0x8:
info.basic.param1 = info.basic.param2 = 0;
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:
debug(10, "MidiParser_S1D: Unexpected type 0x%02X found", (int) info.event);
break;
}
break;
default:
debug(10, "MidiParser_S1D: Unexpected event 0x%02X found", (int) info.command());
break;
}
}
bool MidiParser_S1D::loadMusic(byte *data, uint32 size) {
unloadMusic();
byte *pos = data;
if (*(pos++) != 0xFC)
debug(1, "Expected 0xFC header but found 0x%02X instead", (int) *pos);
// The next 3 bytes MIGHT be tempo, but we skip them and use the default.
// setTempo (*(pos++) | (*(pos++) << 8) | (*(pos++) << 16));
pos += 3;
// And now we're at the actual data. Only one track.
_num_tracks = 1;
_data = pos;
_tracks[0] = pos;
// 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(666667);
setTrack(0);
return true;
}
void MidiParser_S1D::resetTracking() {
MidiParser::resetTracking();
_no_delta = false;
}
MidiParser *MidiParser_createS1D() { return new MidiParser_S1D; }
} // End of namespace AGOS
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