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midiparser_eup.cpp

/* ScummVM - Scumm Interpreter
 * Copyright (C) 2001-2005 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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 *
 * $Header: /cvsroot/scummvm/scummvm/scumm/midiparser_eup.cpp,v 1.18.2.1 2005/10/18 02:11:21 sev Exp $
 *
 */

#include "common/stdafx.h"
#include "sound/midiparser.h"
#include "sound/mididrv.h"
#include "common/util.h"

namespace Scumm {

/**
 * The FM-TOWNS Euphony version of MidiParser.
 */
00032 class MidiParser_EUP : public MidiParser {
protected:
      byte _instruments[6][50]; // Two extra bytes for SysEx ID and channel #
      byte *_instr_to_channel;
      struct {
            byte *enable;
            int8 *channel;
            int8 *volume;
            int8 *transpose;
      } _presets;
      bool _loop;
      byte _presend;     // Tracks which startup implied events have been sent.
      uint32 _base_tick; // Events times are relative to this base.

protected:
      void parseNextEvent (EventInfo &info);
      void resetTracking();

public:
      bool loadMusic (byte *data, uint32 size);
};



//////////////////////////////////////////////////
//
// MidiParser_EUP implementation
//
//////////////////////////////////////////////////

void MidiParser_EUP::parseNextEvent (EventInfo &info) {
      byte *pos = _position._play_pos;

      // FIXME: The presend is for sending init events
      // that aren't actually in the stream. This would
      // be for, e.g., instrument setup. Right now, we
      // don't actually use the instruments specified
      // in the music header. We're sending fixed GM
      // program changes to get a reasonable "one-size-
      // fits-all" sound until we actually support the
      // FM synthesis capabilities of FM-TOWNS.
      for (; _presend < 12; ++_presend) {
            if (_instr_to_channel[_presend >> 1] >= 16)
                  continue;
            info.start = pos;
            info.delta = 0;
            if (_presend & 1) {
                  byte *data = &_instruments[_presend >> 1][0];
                  data[1] = _instr_to_channel[_presend >> 1];
                  info.event = 0xF0;
                  info.ext.data = data;
                  info.length = 48;
            } else {
                  info.event = 0xB0 | (_presend >> 1);
                  info.basic.param1 = 121;
                  info.basic.param2 = 0;
            }
            ++_presend;
            return;
      }

      while (true) {
            byte cmd = *pos;
            if ((cmd & 0xF0) == 0x90) {
                  byte preset = pos[1];
                  byte channel = _presets.channel[preset];
                  if (channel >= 16)
                        channel = cmd & 0x0F;
                  uint16 tick = (pos[2] | ((uint16) pos[3] << 7)) + _base_tick;
                  int note = (int) pos[4] + _presets.transpose[preset];
                  int volume = (int) pos[5];
                  // HACK: Loom-Towns distaff tracks seem to
                  // contain zero-volume note events, so change
                  // those to full volume.
                  if (!volume)
                        volume = 127;
                  volume += _presets.volume[preset];
                  if (volume > 127)
                        volume = 127;
                  else if (volume < 0)
                        volume = 0;
                  pos += 6;
                  if (_presets.enable[preset]) {
                        uint16 duration = pos[1] | (pos[2] << 4);
                        info.start = pos;
                        uint32 last = _position._last_event_tick;
                        info.delta = (tick < last) ? 0 : (tick - last);
                        info.event = 0x90 | channel;
                        info.length = duration;
                        info.basic.param1 = note;
                        info.basic.param2 = volume;
                        pos += 6;
                        break;
                  }
                  pos += 6;
            } else if (cmd == 0xF2) {
                  // This is a "measure marker" of sorts.
                  // It advances the "base time", to which
                  // all event times are relative.
                  _base_tick += (pos[3] << 7) | pos[2];
                  pos += 6;
            } else if (cmd == 0xF8) {
                  // TODO: Implement this.
                  pos += 6;
            } else if (cmd == 0xFD || cmd == 0xFE) {
                  // End of track.
                  if (_loop && false) {
                        // TODO: Implement this.
                  } else {
                        info.start = pos;
                        uint32 last = _position._last_event_tick;
                        info.delta = (_base_tick < last) ? 0 : (_base_tick - last);
                        info.event = 0xFF;
                        info.length = 0;
                        info.ext.type = 0x2F;
                        info.ext.data = pos;
                        break;
                  }
            } else {
                  error("Unknown Euphony music event 0x%02X", (int) cmd);
                  memset(&info, 0, sizeof(info));
                  pos = 0;
                  break;
            }
      }
      _position._play_pos = pos;
}

bool MidiParser_EUP::loadMusic (byte *data, uint32 size) {
      unloadMusic();
      byte *pos = data;
      int i;

      if (memcmp(pos, "SO", 2)) {
            error("'SO' header expected but found '%c%c' instead.", pos[0], pos[1]);
            return false;
      }

      byte numInstruments = pos[16];
      pos += 16 + 2;
      for (i = 0; i < numInstruments; ++i) {
            _instruments[i][0] = 0x7C;
            memcpy (&_instruments[i][2], pos, 48);
            pos += 48;
      }

      // Load the prest pointers
      _presets.enable = pos;
      pos += 32;
      _presets.channel = (int8 *) pos;
      pos += 32;
      _presets.volume = (int8 *) pos;
      pos += 32;
      _presets.transpose = (int8 *) pos;
      pos += 32;

      pos += 8; // Unknown bytes
      _instr_to_channel = pos; // Instrument-to-channel mapping
      pos += 6;
      pos += 4; // Skip the music size for now.
      pos++;    // Unknown byte
      byte tempo = *pos++;
      _loop = (*pos++ != 1);
      pos++;    // Unknown byte

      _num_tracks = 1;
      _ppqn = 120;
      _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 (1000000 * 60 / tempo);
      setTrack (0);
      return true;
}

void MidiParser_EUP::resetTracking() {
      MidiParser::resetTracking();
      _presend = 0;
      _base_tick = 0;
}

MidiParser *MidiParser_createEUP() { return new MidiParser_EUP; }

} // End of namespace Scumm

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