mirror of
https://github.com/libretro/scummvm.git
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352 lines
9.0 KiB
C++
352 lines
9.0 KiB
C++
/* ScummVM - Scumm Interpreter
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* Copyright (C) 2001-2003 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., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
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*
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* $Header$
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*
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*/
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#include "stdafx.h"
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#include "midiparser.h"
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#include "mididrv.h"
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#include "common/util.h"
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/**
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* The Standard MIDI File version of MidiParser.
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*/
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class MidiParser_SMF : public MidiParser {
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protected:
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byte *_buffer;
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bool _malformedPitchBends;
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protected:
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void compressToType0();
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void parseNextEvent (EventInfo &info);
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public:
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MidiParser_SMF() : _buffer(0), _malformedPitchBends(false) {}
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~MidiParser_SMF();
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bool loadMusic (byte *data, uint32 size);
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void property (int property, int value);
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};
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static const byte command_lengths[8] = { 3, 3, 3, 3, 2, 2, 3, 0 };
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static const byte special_lengths[16] = { 0, 1, 1, 3, 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0 };
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MidiParser_SMF::~MidiParser_SMF() {
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if (_buffer)
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free (_buffer);
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}
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void MidiParser_SMF::property (int prop, int value) {
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switch (prop) {
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case mpMalformedPitchBends:
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_malformedPitchBends = (value > 0);
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default:
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MidiParser::property (prop, value);
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}
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}
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void MidiParser_SMF::parseNextEvent (EventInfo &info) {
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info.start = _position._play_pos;
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info.delta = readVLQ (_position._play_pos);
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// Process the next info. If mpMalformedPitchBends
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// was set, we must skip over any pitch bend events
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// because they are from Simon games and are not
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// real pitch bend events, they're just two-byte
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// prefixes before the real info.
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do {
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if ((_position._play_pos[0] & 0xF0) >= 0x80)
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info.event = *(_position._play_pos++);
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else
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info.event = _position._running_status;
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} while (_malformedPitchBends && (info.event & 0xF0) == 0xE0 && _position._play_pos++);
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if (info.event < 0x80)
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return;
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_position._running_status = info.event;
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switch (info.command()) {
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case 0xC: case 0xD:
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info.basic.param1 = *(_position._play_pos++);
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info.basic.param2 = 0;
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break;
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case 0x8: case 0x9: case 0xA: case 0xB: case 0xE:
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info.basic.param1 = *(_position._play_pos++);
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info.basic.param2 = *(_position._play_pos++);
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if (info.command() == 0x9 && info.basic.param2 == 0)
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info.event = info.channel() | 0x80;
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info.length = 0;
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break;
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case 0xF: // System Common, Meta or SysEx event
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switch (info.event & 0x0F) {
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case 0x2: // Song Position Pointer
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info.basic.param1 = *(_position._play_pos++);
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info.basic.param2 = *(_position._play_pos++);
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break;
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case 0x3: // Song Select
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info.basic.param1 = *(_position._play_pos++);
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info.basic.param2 = 0;
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break;
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case 0x6: case 0x8: case 0xA: case 0xB: case 0xC: case 0xE:
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info.basic.param1 = info.basic.param2 = 0;
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break;
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case 0x0: // SysEx
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info.length = readVLQ (_position._play_pos);
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info.ext.data = _position._play_pos;
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_position._play_pos += info.length;
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break;
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case 0xF: // META event
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info.ext.type = *(_position._play_pos++);
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info.length = readVLQ (_position._play_pos);
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info.ext.data = _position._play_pos;
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_position._play_pos += info.length;
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break;
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}
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}
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}
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bool MidiParser_SMF::loadMusic (byte *data, uint32 size) {
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uint32 len;
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byte midi_type;
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uint32 total_size;
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bool isGMF;
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unloadMusic();
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byte *pos = data;
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isGMF = false;
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if (!memcmp (pos, "RIFF", 4)) {
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// Skip the outer RIFF header.
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pos += 8;
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}
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if (!memcmp (pos, "MThd", 4)) {
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// SMF with MTHd information.
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pos += 4;
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len = read4high (pos);
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if (len != 6) {
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printf ("Warning: MThd length 6 expected but found %d\n", (int) len);
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return false;
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}
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// Verify that this MIDI either is a Type 2
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// or has only 1 track. We do not support
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// multitrack Type 1 files.
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_num_tracks = pos[2] << 8 | pos[3];
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midi_type = pos[1];
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if (midi_type > 2 /*|| (midi_type < 2 && _num_tracks > 1)*/) {
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printf ("Warning: No support for a Type %d MIDI with %d tracks\n", (int) midi_type, (int) _num_tracks);
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return false;
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}
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_ppqn = pos[4] << 8 | pos[5];
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pos += len;
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} else if (!memcmp (pos, "GMF\x1", 4)) {
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// Older GMD/MUS file with no header info.
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// Assume 1 track, 192 PPQN, and no MTrk headers.
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isGMF = true;
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midi_type = 0;
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_num_tracks = 1;
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_ppqn = 192;
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pos += 7; // 'GMD\x1' + 3 bytes of useless (translate: unknown) information
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} else {
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printf ("Expected MThd or GMD header but found '%c%c%c%c' instead.\n", pos[0], pos[1], pos[2], pos[3]);
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return false;
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}
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// Now we identify and store the location for each track.
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if (_num_tracks > ARRAYSIZE(_tracks)) {
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printf ("Can only handle %d tracks but was handed %d\n", (int) ARRAYSIZE(_tracks), (int) _num_tracks);
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return false;
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}
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total_size = 0;
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int tracks_read = 0;
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while (tracks_read < _num_tracks) {
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if (memcmp (pos, "MTrk", 4) && !isGMF) {
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printf ("Position: %p ('%c')\n", pos, *pos);
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printf ("Hit invalid block '%c%c%c%c' while scanning for track locations\n", pos[0], pos[1], pos[2], pos[3]);
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return false;
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}
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// If needed, skip the MTrk and length bytes
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_tracks[tracks_read] = pos + (isGMF ? 0 : 8);
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if (!isGMF) {
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pos += 4;
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len = read4high (pos);
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total_size += len;
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pos += len;
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} else {
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// An SMF End of Track meta event must be placed
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// at the end of the stream.
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data[size++] = 0xFF;
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data[size++] = 0x2F;
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data[size++] = 0x00;
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data[size++] = 0x00;
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}
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++tracks_read;
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}
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// If this is a Type 1 MIDI, we need to now compress
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// our tracks down into a single Type 0 track.
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if (_buffer) {
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free (_buffer);
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_buffer = 0;
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}
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if (midi_type == 1) {
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_buffer = (byte *) calloc (size, 1);
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compressToType0();
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_num_tracks = 1;
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_tracks[0] = _buffer;
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}
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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 (500000);
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setTrack (0);
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return true;
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}
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void MidiParser_SMF::compressToType0() {
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// We assume that _buffer has been allocated
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// to sufficient size for this operation.
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byte *track_pos[16];
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byte running_status[16];
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uint32 track_timer[16];
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uint32 delta;
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int i;
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for (i = 0; i < _num_tracks; ++i) {
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running_status[i] = 0;
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track_pos[i] = _tracks[i];
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track_timer[i] = readVLQ (track_pos[i]);
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running_status[i] = 0;
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}
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int best_i;
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uint32 length;
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byte *output = _buffer;
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byte *pos, *pos2;
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byte event;
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uint32 copy_bytes;
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bool write;
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byte active_tracks = (byte) _num_tracks;
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while (active_tracks) {
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write = true;
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best_i = 255;
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for (i = 0; i < _num_tracks; ++i) {
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if (track_pos[i] && (best_i == 255 || track_timer[i] < track_timer[best_i]))
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best_i = i;
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}
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if (best_i == 255) {
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printf ("Premature end of tracks!\n");
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break;
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}
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// Initial VLQ delta computation
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delta = 0;
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length = track_timer[best_i];
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for (i = 0; length; ++i) {
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delta = (delta << 8) | (length & 0x7F) | (i ? 0x80 : 0);
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length >>= 7;
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}
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// Process MIDI event.
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copy_bytes = 0;
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pos = track_pos[best_i];
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do {
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event = *(pos++);
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if (event < 0x80)
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event = running_status[best_i];
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} while (_malformedPitchBends && (event & 0xF0) == 0xE0 && pos++);
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running_status[best_i] = event;
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if (command_lengths [(event >> 4) - 8] > 0) {
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copy_bytes = command_lengths [(event >> 4) - 8];
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} else if (special_lengths [(event & 0x0F)] > 0) {
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copy_bytes = special_lengths [(event & 0x0F)];
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} else if (event == 0xF0) {
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// SysEx
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pos2 = pos;
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length = readVLQ (pos);
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copy_bytes = 1 + (pos - pos2) + length;
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} else if (event == 0xFF) {
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// META
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event = *(pos++);
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if (event == 0x2F && active_tracks > 1) {
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track_pos[best_i] = 0;
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write = false;
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} else {
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pos2 = pos;
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length = readVLQ (pos);
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copy_bytes = 2 + (pos - pos2) + length;
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}
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if (event == 0x2F)
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--active_tracks;
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} else {
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printf ("Bad MIDI command %02X!\n", (int) event);
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track_pos[best_i] = 0;
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}
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// Update all tracks' deltas
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if (write) {
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for (i = 0; i < _num_tracks; ++i) {
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if (track_pos[i] && i != best_i)
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track_timer[i] -= track_timer[best_i];
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}
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}
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if (track_pos[best_i]) {
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if (write) {
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track_timer[best_i] = 0;
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// Write VLQ delta
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while (delta & 0x80) {
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*output++ = (byte) (delta & 0xFF);
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delta >>= 8;
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}
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*output++ = (byte) (delta & 0xFF);
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// Write MIDI data
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memcpy (output, track_pos[best_i], copy_bytes);
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output += copy_bytes;
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}
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// Fetch new VLQ delta for winning track
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track_pos[best_i] += copy_bytes;
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if (active_tracks)
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track_timer[best_i] += readVLQ (track_pos[best_i]);
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}
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}
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*output++ = 0x00;
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}
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MidiParser *MidiParser::createParser_SMF() { return new MidiParser_SMF; }
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