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engines/scumm/midiparser_ro.cpp

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+/* ScummVM - Graphic Adventure Engine
+ *
+ * ScummVM is the legal property of its developers, whose names
+ * are too numerous to list here. Please refer to the COPYRIGHT
+ * file distributed with this source distribution.
+ *
+ * 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 3 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, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+
+#include "audio/midiparser.h"
+#include "common/textconsole.h"
+
+namespace Scumm {
+
+//////////////////////////////////////////////////
+//
+// The Standard MIDI File version of MidiParser
+//
+//////////////////////////////////////////////////
+
+class MidiParser_RO : public MidiParser {
+protected:
+	int _markerCount = 0;     // Number of markers encountered in stream so far
+	int _lastMarkerCount = 0; // Cache markers until parsed event is actually consumed
+
+	void parseNextEvent (EventInfo &info) override;
+
+public:
+	bool loadMusic(const byte *data, uint32 size) override;
+	uint32 getTick() override { return (uint32) _markerCount * _ppqn / 2; }
+};
+
+
+
+//////////////////////////////////////////////////
+//
+// MidiParser_RO implementation
+//
+//////////////////////////////////////////////////
+
+void MidiParser_RO::parseNextEvent (EventInfo &info) {
+	_markerCount += _lastMarkerCount;
+	_lastMarkerCount = 0;
+
+	const byte *playPos = _position._subtracks[0]._playPos;
+
+	info.delta = 0;
+	do {
+		info.start = playPos;
+		info.event = *(playPos++);
+		if (info.command() == 0xA) {
+			++_lastMarkerCount;
+			info.event = 0xF0;
+		} else if (info.event == 0xF0 || info.event == 0xF1) {
+			byte delay = *(playPos++);
+			info.delta += delay;
+			if (info.event == 0xF1) {
+				// This event is, as far as we have been able
+				// to determine, only used in one single song
+				// in EGA Loom. It seems to be meant for adding
+				// values greater than 255 to info.delta. See
+				// bug #2650.
+				info.delta += 256;
+			}
+			continue;
+		}
+		break;
+	} while (true);
+
+	_position._subtracks[0]._playPos = playPos;
+
+	// Seems to indicate EOT
+	if (info.event == 0) {
+		info.event = 0xFF;
+		info.ext.type = 0x2F;
+		info.length = 0;
+		info.ext.data = nullptr;
+		return;
+	}
+
+	if (info.event < 0x80)
+		return;
+
+	_position._subtracks[0]._runningStatus = info.event;
+	switch (info.command()) {
+	case 0xC:
+		info.basic.param1 = *(playPos++);
+		info.basic.param2 = 0;
+		break;
+
+	case 0x8: case 0x9: case 0xB:
+		info.basic.param1 = *(playPos++);
+		info.basic.param2 = *(playPos++);
+		if (info.command() == 0x9 && info.basic.param2 == 0)
+			info.event = info.channel() | 0x80;
+		info.length = 0;
+		break;
+
+	case 0xF: // Marker and EOT messages
+		info.length = 0;
+		info.ext.data = nullptr;
+		if (info.event == 0xFF) {
+			_autoLoop = true;
+			info.ext.type = 0x2F;
+		} else {
+			info.ext.type = 0x7F; // Bogus META
+		}
+		info.event = 0xFF;
+		break;
+
+	default:
+		break;
+	}
+
+	_position._subtracks[0]._playPos = playPos;
+}
+
+bool MidiParser_RO::loadMusic(const byte *data, uint32 size) {
+	unloadMusic();
+	const byte *pos = data;
+
+	if (memcmp (pos, "RO", 2)) {
+		error("'RO' header expected but found '%c%c' instead", pos[0], pos[1]);
+		return false;
+	}
+
+	_numTracks = 1;
+	_numSubtracks[0] = 1;
+	_autoLoop = false;
+	_ppqn = 120;
+	_tracks[0][0] = pos + 2;
+	_markerCount = _lastMarkerCount = 0;
+
+	// 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 (500000);
+	setTrack (0);
+	return true;
+}
+
+MidiParser *MidiParser_createRO() { return new MidiParser_RO; }
+
+} // End of namespace Scumm