/* 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., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. * * $Header$ * */ #include "common/stdafx.h" #include "midiparser.h" #include "mididrv.h" #include "common/util.h" /** * The XMIDI version of MidiParser. * * Much of this code is adapted from the XMIDI implementation from the exult * project. */ class MidiParser_XMIDI : public MidiParser { protected: NoteTimer _notes_cache[32]; uint32 _inserted_delta; // Track simulated deltas for note-off events protected: uint32 readVLQ2(byte * &data); void resetTracking(); void parseNextEvent(EventInfo &info); public: MidiParser_XMIDI() : _inserted_delta(0) {} ~MidiParser_XMIDI() { } bool loadMusic(byte *data, uint32 size); }; // This is a special XMIDI variable length quantity uint32 MidiParser_XMIDI::readVLQ2(byte * &pos) { uint32 value = 0; int i; for (i = 0; i < 4; ++i) { if (pos[0] & 0x80) break; value += *pos++; } return value; } void MidiParser_XMIDI::parseNextEvent(EventInfo &info) { info.start = _position._play_pos; info.delta = readVLQ2(_position._play_pos) - _inserted_delta; // Process the next event. _inserted_delta = 0; info.event = *(_position._play_pos++); switch (info.event >> 4) { case 0x9: // Note On info.basic.param1 = *(_position._play_pos++); info.basic.param2 = *(_position._play_pos++); info.length = readVLQ(_position._play_pos); if (info.basic.param2 == 0) { info.event = info.channel() | 0x80; info.length = 0; } break; case 0xC: case 0xD: info.basic.param1 = *(_position._play_pos++); info.basic.param2 = 0; break; case 0x8: case 0xA: case 0xB: case 0xE: info.basic.param1 = *(_position._play_pos++); info.basic.param2 = *(_position._play_pos++); break; case 0xF: // Meta or SysEx event switch (info.event & 0x0F) { case 0x2: // Song Position Pointer info.basic.param1 = *(_position._play_pos++); info.basic.param2 = *(_position._play_pos++); break; case 0x3: // Song Select info.basic.param1 = *(_position._play_pos++); info.basic.param2 = 0; break; case 0x6: case 0x8: case 0xA: case 0xB: case 0xC: case 0xE: info.basic.param1 = info.basic.param2 = 0; break; case 0x0: // SysEx info.length = readVLQ(_position._play_pos); info.ext.data = _position._play_pos; _position._play_pos += info.length; break; case 0xF: // META event info.ext.type = *(_position._play_pos++); info.length = readVLQ(_position._play_pos); info.ext.data = _position._play_pos; _position._play_pos += info.length; if (info.ext.type == 0x51 && info.length == 3) { // Tempo event. We want to make these constant 500,000. info.ext.data[0] = 0x07; info.ext.data[1] = 0xA1; info.ext.data[2] = 0x20; } break; } } } bool MidiParser_XMIDI::loadMusic(byte *data, uint32 size) { uint32 i = 0; byte *start; uint32 len; uint32 chunk_len; char buf[32]; unloadMusic(); byte *pos = data; if (!memcmp(pos, "FORM", 4)) { pos += 4; // Read length of len = read4high(pos); start = pos; // XDIRless XMIDI, we can handle them here. if (!memcmp(pos, "XMID", 4)) { warning("XMIDI doesn't have XDIR"); pos += 4; _num_tracks = 1; } else if (memcmp(pos, "XDIR", 4)) { // Not an XMIDI that we recognise warning("Expected 'XDIR' but found '%c%c%c%c'", pos[0], pos[1], pos[2], pos[3]); return false; } else { // Seems Valid pos += 4; _num_tracks = 0; for (i = 4; i < len; i++) { // Read 4 bytes of type memcpy(buf, pos, 4); pos += 4; // Read length of chunk chunk_len = read4high(pos); // Add eight bytes i += 8; if (memcmp(buf, "INFO", 4)) { // Must align pos += (chunk_len + 1) & ~1; i += (chunk_len + 1) & ~1; continue; } // Must be at least 2 bytes long if (chunk_len < 2) { warning("Invalid chunk length %d for 'INFO' block!", (int)chunk_len); return false; } _num_tracks = (byte)read2low(pos); if (chunk_len > 2) { warning("Chunk length %d is greater than 2", (int)chunk_len); pos += chunk_len - 2; } break; } // Didn't get to fill the header if (_num_tracks == 0) { warning("Didn't find a valid track count"); return false; } // Ok now to start part 2 // Goto the right place pos = start + ((len + 1) & ~1); if (memcmp(pos, "CAT ", 4)) { // Not an XMID warning("Expected 'CAT ' but found '%c%c%c%c'", pos[0], pos[1], pos[2], pos[3]); return false; } pos += 4; // Now read length of this track len = read4high(pos); if (memcmp(pos, "XMID", 4)) { // Not an XMID warning("Expected 'XMID' but found '%c%c%c%c'", pos[0], pos[1], pos[2], pos[3]); return false; } pos += 4; } // Ok it's an XMIDI. // We're going to identify and store the location for each track. if (_num_tracks > ARRAYSIZE(_tracks)) { warning("Can only handle %d tracks but was handed %d", (int)ARRAYSIZE(_tracks), (int)_num_tracks); return false; } int tracks_read = 0; while (tracks_read < _num_tracks) { if (!memcmp(pos, "FORM", 4)) { // Skip this plus the 4 bytes after it. pos += 8; } else if (!memcmp(pos, "XMID", 4)) { // Skip this. pos += 4; } else if (!memcmp(pos, "TIMB", 4)) { // Custom timbres? // We don't support them. // Read the length, skip it, and hope there was nothing there. pos += 4; len = read4high(pos); pos += (len + 1) & ~1; } else if (!memcmp(pos, "EVNT", 4)) { // Ahh! What we're looking for at last. _tracks[tracks_read] = pos + 8; // Skip the EVNT and length bytes pos += 4; len = read4high(pos); pos += (len + 1) & ~1; ++tracks_read; } else { warning("Hit invalid block '%c%c%c%c' while scanning for track locations", pos[0], pos[1], pos[2], pos[3]); return false; } } // If we got this far, we successfully established // the locations for each of our tracks. // 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.... _ppqn = 60; resetTracking(); setTempo(500000); _inserted_delta = 0; setTrack(0); return true; } return false; } void MidiParser_XMIDI::resetTracking() { MidiParser::resetTracking(); _inserted_delta = 0; } MidiParser *MidiParser::createParser_XMIDI() { return new MidiParser_XMIDI; }