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midiparser_ro.cpp

/* ScummVM - Scumm Interpreter
 * Copyright (C) 2001-2004 The ScummVM project
 *
 * 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., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
 *
 * $Header: /cvsroot/scummvm/scummvm/scumm/midiparser_ro.cpp,v 1.6 2004/01/11 21:57:24 fingolfin Exp $
 *
 */

#include "stdafx.h"
#include "sound/midiparser.h"
#include "sound/mididrv.h"
#include "common/util.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._play_pos;
            info.event = *(_position._play_pos++);
            if (info.command() == 0xA) {
                  ++_lastMarkerCount;
                  info.event = 0xF0;
            } else if (info.event == 0xF0) {
                  byte delay = *(_position._play_pos++);
                  info.delta += delay;
                  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._running_status = info.event;
      switch (info.command()) {
      case 0xC:
            info.basic.param1 = *(_position._play_pos++);
            info.basic.param2 = 0;
            break;

      case 0x8: case 0x9: case 0xB:
            info.basic.param1 = *(_position._play_pos++);
            info.basic.param2 = *(_position._play_pos++);
            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)) {
            warning("'RO' header expected but found '%c%c' instead", pos[0], pos[1]);
            return false;
      }

      _num_tracks = 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

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