mirror of
https://github.com/libretro/scummvm.git
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281 lines
7.0 KiB
C++
281 lines
7.0 KiB
C++
/* ScummVM - Scumm Interpreter
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* Copyright (C) 2001-2005 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 XMIDI version of MidiParser.
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*
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* Much of this code is adapted from the XMIDI implementation from the exult
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* project.
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*/
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class MidiParser_XMIDI : public MidiParser {
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protected:
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NoteTimer _notes_cache[32];
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uint32 _inserted_delta; // Track simulated deltas for note-off events
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protected:
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uint32 readVLQ2(byte * &data);
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void resetTracking();
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void parseNextEvent(EventInfo &info);
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public:
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MidiParser_XMIDI() : _inserted_delta(0) {}
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~MidiParser_XMIDI() { }
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bool loadMusic(byte *data, uint32 size);
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};
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// This is a special XMIDI variable length quantity
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uint32 MidiParser_XMIDI::readVLQ2(byte * &pos) {
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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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if (pos[0] & 0x80)
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break;
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value += *pos++;
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}
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return value;
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}
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void MidiParser_XMIDI::parseNextEvent(EventInfo &info) {
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info.start = _position._play_pos;
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info.delta = readVLQ2(_position._play_pos) - _inserted_delta;
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// Process the next event.
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_inserted_delta = 0;
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info.event = *(_position._play_pos++);
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switch (info.event >> 4) {
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case 0x9: // Note On
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info.basic.param1 = *(_position._play_pos++);
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info.basic.param2 = *(_position._play_pos++);
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info.length = readVLQ(_position._play_pos);
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if (info.basic.param2 == 0) {
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info.event = info.channel() | 0x80;
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info.length = 0;
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}
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break;
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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 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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break;
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case 0xF: // 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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if (info.ext.type == 0x51 && info.length == 3) {
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// Tempo event. We want to make these constant 500,000.
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info.ext.data[0] = 0x07;
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info.ext.data[1] = 0xA1;
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info.ext.data[2] = 0x20;
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}
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break;
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}
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}
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}
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bool MidiParser_XMIDI::loadMusic(byte *data, uint32 size) {
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uint32 i = 0;
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byte *start;
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uint32 len;
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uint32 chunk_len;
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char buf[32];
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unloadMusic();
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byte *pos = data;
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if (!memcmp(pos, "FORM", 4)) {
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pos += 4;
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// Read length of
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len = read4high(pos);
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start = pos;
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// XDIRless XMIDI, we can handle them here.
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if (!memcmp(pos, "XMID", 4)) {
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warning("XMIDI doesn't have XDIR");
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pos += 4;
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_num_tracks = 1;
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} else if (memcmp(pos, "XDIR", 4)) {
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// Not an XMIDI that we recognise
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warning("Expected 'XDIR' but found '%c%c%c%c'", pos[0], pos[1], pos[2], pos[3]);
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return false;
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} else {
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// Seems Valid
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pos += 4;
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_num_tracks = 0;
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for (i = 4; i < len; i++) {
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// Read 4 bytes of type
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memcpy(buf, pos, 4);
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pos += 4;
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// Read length of chunk
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chunk_len = read4high(pos);
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// Add eight bytes
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i += 8;
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if (memcmp(buf, "INFO", 4)) {
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// Must align
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pos += (chunk_len + 1) & ~1;
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i += (chunk_len + 1) & ~1;
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continue;
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}
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// Must be at least 2 bytes long
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if (chunk_len < 2) {
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warning("Invalid chunk length %d for 'INFO' block!", (int) chunk_len);
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return false;
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}
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_num_tracks = (byte) read2low(pos);
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if (chunk_len > 2) {
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warning("Chunk length %d is greater than 2", (int) chunk_len);
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pos += chunk_len - 2;
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}
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break;
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}
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// Didn't get to fill the header
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if (_num_tracks == 0) {
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warning("Didn't find a valid track count");
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return false;
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}
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// Ok now to start part 2
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// Goto the right place
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pos = start + ((len + 1) & ~1);
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if (memcmp(pos, "CAT ", 4)) {
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// Not an XMID
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warning("Expected 'CAT ' but found '%c%c%c%c'", pos[0], pos[1], pos[2], pos[3]);
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return false;
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}
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pos += 4;
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// Now read length of this track
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len = read4high(pos);
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if (memcmp(pos, "XMID", 4)) {
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// Not an XMID
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warning("Expected 'XMID' but found '%c%c%c%c'", pos[0], pos[1], pos[2], pos[3]);
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return false;
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}
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pos += 4;
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}
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// Ok it's an XMIDI.
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// We're going to identify and store the location for each track.
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if (_num_tracks > ARRAYSIZE(_tracks)) {
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warning("Can only handle %d tracks but was handed %d", (int) ARRAYSIZE(_tracks), (int) _num_tracks);
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return false;
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}
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int tracks_read = 0;
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while (tracks_read < _num_tracks) {
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if (!memcmp(pos, "FORM", 4)) {
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// Skip this plus the 4 bytes after it.
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pos += 8;
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} else if (!memcmp(pos, "XMID", 4)) {
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// Skip this.
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pos += 4;
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} else if (!memcmp(pos, "TIMB", 4)) {
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// Custom timbres?
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// We don't support them.
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// Read the length, skip it, and hope there was nothing there.
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pos += 4;
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len = read4high(pos);
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pos += (len + 1) & ~1;
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} else if (!memcmp(pos, "EVNT", 4)) {
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// Ahh! What we're looking for at last.
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_tracks[tracks_read] = pos + 8; // Skip the EVNT and length bytes
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pos += 4;
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len = read4high(pos);
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pos += (len + 1) & ~1;
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++tracks_read;
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} else {
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warning("Hit invalid block '%c%c%c%c' while scanning for track locations", pos[0], pos[1], pos[2], pos[3]);
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return false;
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}
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}
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// If we got this far, we successfully established
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// the locations for each of our tracks.
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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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_ppqn = 60;
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resetTracking();
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setTempo(500000);
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_inserted_delta = 0;
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setTrack(0);
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return true;
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}
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return false;
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}
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void MidiParser_XMIDI::resetTracking() {
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MidiParser::resetTracking();
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_inserted_delta = 0;
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}
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MidiParser *MidiParser::createParser_XMIDI() { return new MidiParser_XMIDI; }
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