mirror of
https://github.com/libretro/scummvm.git
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156 lines
3.7 KiB
C++
156 lines
3.7 KiB
C++
/* ScummVM - Scumm Interpreter
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* Copyright (C) 2001 Ludvig Strigeus
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* Copyright (C) 2001-2006 The ScummVM project
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version 2
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* of the License, or (at your option) any later version.
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
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*
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* $URL$
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* $Id$
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*
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*/
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#include "common/stdafx.h"
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#include "common/util.h"
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#include "sound/mididrv.h"
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#include "sound/midiparser.h"
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#include <stdio.h>
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namespace AGOS {
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/**
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* Simon 1 Demo version of MidiParser.
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*
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* This parser is the result of eyeballing the one MUS file that's included
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* with simon1demo. So there might be some things missing. I've tried to notate
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* question-mark areas where they occur.
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*/
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class MidiParser_S1D : public MidiParser {
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protected:
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byte *_data;
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bool _no_delta;
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protected:
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void parseNextEvent (EventInfo &info);
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void resetTracking();
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uint32 readVLQ2(byte * &data);
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public:
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MidiParser_S1D() : _data(0), _no_delta(false) {}
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bool loadMusic(byte *data, uint32 size);
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};
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// The VLQs for simon1demo seem to be
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// in Little Endian format.
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uint32 MidiParser_S1D::readVLQ2(byte * &data) {
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byte str;
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uint32 value = 0;
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int i;
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for (i = 0; i < 4; ++i) {
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str = data[0];
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++data;
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value |= (str & 0x7F) << (i * 7);
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if (!(str & 0x80))
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break;
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}
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return value;
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}
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void MidiParser_S1D::parseNextEvent(EventInfo &info) {
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info.start = _position._play_pos;
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info.delta = _no_delta ? 0 : readVLQ2(_position._play_pos);
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_no_delta = false;
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info.event = *(_position._play_pos++);
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if (info.command() < 0x8) {
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_no_delta = true;
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info.event += 0x80;
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}
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switch (info.command()) {
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case 0x8:
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info.basic.param1 = *(_position._play_pos++);
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info.basic.param2 = 0;
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info.length = 0;
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break;
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case 0x9:
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info.basic.param1 = *(_position._play_pos++);
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info.basic.param2 = *(_position._play_pos++); // I'm ASSUMING this byte is velocity!
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info.length = 0;
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break;
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case 0xC:
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info.basic.param1 = *(_position._play_pos++);
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info.basic.param2 = 0;
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++_position._play_pos; // I have NO IDEA what the second byte is for.
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break;
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case 0xF:
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if (info.event == 0xFC) {
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// This means End of Track.
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// Rewrite in SMF (MIDI transmission) form.
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info.event = 0xFF;
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info.ext.type = 0x2F;
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info.length = 0;
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break;
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}
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// OTherwise fall through to default.
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default:
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debug(3, "MidiParser_S1D: Unexpected byte 0x%02X found", (int) info.command());
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break;
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}
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}
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bool MidiParser_S1D::loadMusic(byte *data, uint32 size) {
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unloadMusic();
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byte *pos = data;
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if (*(pos++) != 0xFC)
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debug(1, "Expected 0xFC header but found 0x%02X instead", (int) *pos);
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// The next 3 bytes MIGHT be tempo, but we skip them and use the default.
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// setTempo (*(pos++) | (*(pos++) << 8) | (*(pos++) << 16));
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pos += 3;
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// And now we're at the actual data. Only one track.
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_num_tracks = 1;
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_data = pos;
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_tracks[0] = pos;
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// Note that we assume the original data passed in
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// will persist beyond this call, i.e. we do NOT
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// copy the data to our own buffer. Take warning....
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resetTracking();
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setTempo(666667);
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setTrack(0);
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return true;
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}
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void MidiParser_S1D::resetTracking() {
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MidiParser::resetTracking();
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_no_delta = false;
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}
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MidiParser *MidiParser_createS1D() { return new MidiParser_S1D; }
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} // End of namespace AGOS
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