scummvm/engines/scumm/midiparser_ro.cpp
2016-04-14 16:10:21 +03:00

151 lines
3.8 KiB
C++

/* 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.
*
*/
#include "audio/midiparser.h"
#include "common/textconsole.h"
namespace Scumm {
//////////////////////////////////////////////////
//
// The Standard MIDI File version of MidiParser
//
//////////////////////////////////////////////////
class MidiParser_RO : public MidiParser {
protected:
int _markerCount; // Number of markers encountered in stream so far
int _lastMarkerCount; // Cache markers until parsed event is actually consumed
protected:
void compressToType0();
void parseNextEvent (EventInfo &info);
public:
bool loadMusic (byte *data, uint32 size);
uint32 getTick() { return (uint32) _markerCount * _ppqn / 2; }
};
//////////////////////////////////////////////////
//
// MidiParser_RO implementation
//
//////////////////////////////////////////////////
void MidiParser_RO::parseNextEvent (EventInfo &info) {
_markerCount += _lastMarkerCount;
_lastMarkerCount = 0;
info.delta = 0;
do {
info.start = _position._playPos;
info.event = *(_position._playPos++);
if (info.command() == 0xA) {
++_lastMarkerCount;
info.event = 0xF0;
} else if (info.event == 0xF0 || info.event == 0xF1) {
byte delay = *(_position._playPos++);
info.delta += delay;
if (info.event == 0xF1) {
// This event is, as far as we have been able
// to determine, only used in one single song
// in EGA Loom. It seems to be meant for adding
// values greater than 255 to info.delta. See
// bug #1498785.
info.delta += 256;
}
continue;
}
break;
} while (true);
// Seems to indicate EOT
if (info.event == 0) {
info.event = 0xFF;
info.ext.type = 0x2F;
info.length = 0;
info.ext.data = 0;
return;
}
if (info.event < 0x80)
return;
_position._runningStatus = info.event;
switch (info.command()) {
case 0xC:
info.basic.param1 = *(_position._playPos++);
info.basic.param2 = 0;
break;
case 0x8: case 0x9: case 0xB:
info.basic.param1 = *(_position._playPos++);
info.basic.param2 = *(_position._playPos++);
if (info.command() == 0x9 && info.basic.param2 == 0)
info.event = info.channel() | 0x80;
info.length = 0;
break;
case 0xF: // Marker and EOT messages
info.length = 0;
info.ext.data = 0;
if (info.event == 0xFF) {
_autoLoop = true;
info.ext.type = 0x2F;
} else {
info.ext.type = 0x7F; // Bogus META
}
info.event = 0xFF;
break;
}
}
bool MidiParser_RO::loadMusic (byte *data, uint32 size) {
unloadMusic();
byte *pos = data;
if (memcmp (pos, "RO", 2)) {
error("'RO' header expected but found '%c%c' instead", pos[0], pos[1]);
return false;
}
_numTracks = 1;
_ppqn = 120;
_tracks[0] = pos + 2;
_markerCount = _lastMarkerCount = 0;
// 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;
}
MidiParser *MidiParser_createRO() { return new MidiParser_RO; }
} // End of namespace Scumm