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	/*
	* Copyright (c) 2003, 2013, Oracle and/or its affiliates. All rights reserved.
	* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
	*
	* This code is free software; you can redistribute it and/or modify it
	* under the terms of the GNU General Public License version 2 only, as
	* published by the Free Software Foundation. Oracle designates this
	* particular file as subject to the "Classpath" exception as provided
	* by Oracle in the LICENSE file that accompanied this code.
	*
	* This code 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
	* version 2 for more details (a copy is included in the LICENSE file that
	* accompanied this code).
	*
	* You should have received a copy of the GNU General Public License version
	* 2 along with this work; if not, write to the Free Software Foundation,
	* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
	*
	* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
	* or visit www.oracle.com if you need additional information or have any
	* questions.
	*/

	package com.sun.media.sound;

	import javax.sound.midi.*;
	import java.util.ArrayList;

	// TODO:
	// - define and use a global symbolic constant for 60000000 (see convertTempo)

	/**
	* Some utilities for MIDI (some stuff is used from javax.sound.midi)
	*
	* @author Florian Bomers
	*/
	public final class MidiUtils {

	public final static int DEFAULT_TEMPO_MPQ = 500000; // 120bpm
	public final static int META_END_OF_TRACK_TYPE = 0x2F;
	public final static int META_TEMPO_TYPE = 0x51;

	/**
	* Suppresses default constructor, ensuring non-instantiability.
	*/
	private MidiUtils() {
	}

	/** return true if the passed message is Meta End Of Track */
	public static boolean isMetaEndOfTrack(MidiMessage midiMsg) {
	// first check if it is a META message at all
	if (midiMsg.getLength() != 3
	\|\| midiMsg.getStatus() != MetaMessage.META) {
	return false;
	}
	// now get message and check for end of track
	byte[] msg = midiMsg.getMessage();
	return ((msg[1] & 0xFF) == META_END_OF_TRACK_TYPE) && (msg[2] == 0);
	}


	/** return if the given message is a meta tempo message */
	public static boolean isMetaTempo(MidiMessage midiMsg) {
	// first check if it is a META message at all
	if (midiMsg.getLength() != 6
	\|\| midiMsg.getStatus() != MetaMessage.META) {
	return false;
	}
	// now get message and check for tempo
	byte[] msg = midiMsg.getMessage();
	// meta type must be 0x51, and data length must be 3
	return ((msg[1] & 0xFF) == META_TEMPO_TYPE) && (msg[2] == 3);
	}


	/** parses this message for a META tempo message and returns
	* the tempo in MPQ, or -1 if this isn't a tempo message
	*/
	public static int getTempoMPQ(MidiMessage midiMsg) {
	// first check if it is a META message at all
	if (midiMsg.getLength() != 6
	\|\| midiMsg.getStatus() != MetaMessage.META) {
	return -1;
	}
	byte[] msg = midiMsg.getMessage();
	if (((msg[1] & 0xFF) != META_TEMPO_TYPE) \|\| (msg[2] != 3)) {
	return -1;
	}
	int tempo = (msg[5] & 0xFF)
	\| ((msg[4] & 0xFF) << 8)
	\| ((msg[3] & 0xFF) << 16);
	return tempo;
	}


	/**
	* converts<br>
	* 1 - MPQ-Tempo to BPM tempo<br>
	* 2 - BPM tempo to MPQ tempo<br>
	*/
	public static double convertTempo(double tempo) {
	if (tempo <= 0) {
	tempo = 1;
	}
	return ((double) 60000000l) / tempo;
	}


	/**
	* convert tick to microsecond with given tempo.
	* Does not take tempo changes into account.
	* Does not work for SMPTE timing!
	*/
	public static long ticks2microsec(long tick, double tempoMPQ, int resolution) {
	return (long) (((double) tick) * tempoMPQ / resolution);
	}

	/**
	* convert tempo to microsecond with given tempo
	* Does not take tempo changes into account.
	* Does not work for SMPTE timing!
	*/
	public static long microsec2ticks(long us, double tempoMPQ, int resolution) {
	// do not round to nearest tick
	//return (long) Math.round((((double)us) * resolution) / tempoMPQ);
	return (long) ((((double)us) * resolution) / tempoMPQ);
	}


	/**
	* Given a tick, convert to microsecond
	* @param cache tempo info and current tempo
	*/
	public static long tick2microsecond(Sequence seq, long tick, TempoCache cache) {
	if (seq.getDivisionType() != Sequence.PPQ ) {
	double seconds = ((double)tick / (double)(seq.getDivisionType() * seq.getResolution()));
	return (long) (1000000 * seconds);
	}

	if (cache == null) {
	cache = new TempoCache(seq);
	}

	int resolution = seq.getResolution();

	long[] ticks = cache.ticks;
	int[] tempos = cache.tempos; // in MPQ
	int cacheCount = tempos.length;

	// optimization to not always go through entire list of tempo events
	int snapshotIndex = cache.snapshotIndex;
	int snapshotMicro = cache.snapshotMicro;

	// walk through all tempo changes and add time for the respective blocks
	long us = 0; // microsecond

	if (snapshotIndex <= 0
	\|\| snapshotIndex >= cacheCount
	\|\| ticks[snapshotIndex] > tick) {
	snapshotMicro = 0;
	snapshotIndex = 0;
	}
	if (cacheCount > 0) {
	// this implementation needs a tempo event at tick 0!
	int i = snapshotIndex + 1;
	while (i < cacheCount && ticks[i] <= tick) {
	snapshotMicro += ticks2microsec(ticks[i] - ticks[i - 1], tempos[i - 1], resolution);
	snapshotIndex = i;
	i++;
	}
	us = snapshotMicro
	+ ticks2microsec(tick - ticks[snapshotIndex],
	tempos[snapshotIndex],
	resolution);
	}
	cache.snapshotIndex = snapshotIndex;
	cache.snapshotMicro = snapshotMicro;
	return us;
	}

	/**
	* Given a microsecond time, convert to tick.
	* returns tempo at the given time in cache.getCurrTempoMPQ
	*/
	public static long microsecond2tick(Sequence seq, long micros, TempoCache cache) {
	if (seq.getDivisionType() != Sequence.PPQ ) {
	double dTick = ( ((double) micros)
	* ((double) seq.getDivisionType())
	* ((double) seq.getResolution()))
	/ ((double) 1000000);
	long tick = (long) dTick;
	if (cache != null) {
	cache.currTempo = (int) cache.getTempoMPQAt(tick);
	}
	return tick;
	}

	if (cache == null) {
	cache = new TempoCache(seq);
	}
	long[] ticks = cache.ticks;
	int[] tempos = cache.tempos; // in MPQ
	int cacheCount = tempos.length;

	int resolution = seq.getResolution();

	long us = 0; long tick = 0; int newReadPos = 0; int i = 1;

	// walk through all tempo changes and add time for the respective blocks
	// to find the right tick
	if (micros > 0 && cacheCount > 0) {
	// this loop requires that the first tempo Event is at time 0
	while (i < cacheCount) {
	long nextTime = us + ticks2microsec(ticks[i] - ticks[i - 1],
	tempos[i - 1], resolution);
	if (nextTime > micros) {
	break;
	}
	us = nextTime;
	i++;
	}
	tick = ticks[i - 1] + microsec2ticks(micros - us, tempos[i - 1], resolution);
	if (Printer.debug) Printer.debug("microsecond2tick(" + (micros / 1000)+") = "+tick+" ticks.");
	//if (Printer.debug) Printer.debug(" -> convert back = " + (tick2microsecond(seq, tick, null) / 1000)+" microseconds");
	}
	cache.currTempo = tempos[i - 1];
	return tick;
	}


	/**
	* Binary search for the event indexes of the track
	*
	* @param tick - tick number of index to be found in array
	* @return index in track which is on or after "tick".
	* if no entries are found that follow after tick, track.size() is returned
	*/
	public static int tick2index(Track track, long tick) {
	int ret = 0;
	if (tick > 0) {
	int low = 0;
	int high = track.size() - 1;
	while (low < high) {
	// take the middle event as estimate
	ret = (low + high) >> 1;
	// tick of estimate
	long t = track.get(ret).getTick();
	if (t == tick) {
	break;
	} else if (t < tick) {
	// estimate too low
	if (low == high - 1) {
	// "or after tick"
	ret++;
	break;
	}
	low = ret;
	} else { // if (t>tick)
	// estimate too high
	high = ret;
	}
	}
	}
	return ret;
	}


	public static final class TempoCache {
	long[] ticks;
	int[] tempos; // in MPQ
	// index in ticks/tempos at the snapshot
	int snapshotIndex = 0;
	// microsecond at the snapshot
	int snapshotMicro = 0;

	int currTempo; // MPQ, used as return value for microsecond2tick

	private boolean firstTempoIsFake = false;

	public TempoCache() {
	// just some defaults, to prevents weird stuff
	ticks = new long[1];
	tempos = new int[1];
	tempos[0] = DEFAULT_TEMPO_MPQ;
	snapshotIndex = 0;
	snapshotMicro = 0;
	}

	public TempoCache(Sequence seq) {
	this();
	refresh(seq);
	}


	public synchronized void refresh(Sequence seq) {
	ArrayList list = new ArrayList();
	Track[] tracks = seq.getTracks();
	if (tracks.length > 0) {
	// tempo events only occur in track 0
	Track track = tracks[0];
	int c = track.size();
	for (int i = 0; i < c; i++) {
	MidiEvent ev = track.get(i);
	MidiMessage msg = ev.getMessage();
	if (isMetaTempo(msg)) {
	// found a tempo event. Add it to the list
	list.add(ev);
	}
	}
	}
	int size = list.size() + 1;
	firstTempoIsFake = true;
	if ((size > 1)
	&& (((MidiEvent) list.get(0)).getTick() == 0)) {
	// do not need to add an initial tempo event at the beginning
	size--;
	firstTempoIsFake = false;
	}
	ticks = new long[size];
	tempos = new int[size];
	int e = 0;
	if (firstTempoIsFake) {
	// add tempo 120 at beginning
	ticks[0] = 0;
	tempos[0] = DEFAULT_TEMPO_MPQ;
	e++;
	}
	for (int i = 0; i < list.size(); i++, e++) {
	MidiEvent evt = (MidiEvent) list.get(i);
	ticks[e] = evt.getTick();
	tempos[e] = getTempoMPQ(evt.getMessage());
	}
	snapshotIndex = 0;
	snapshotMicro = 0;
	}

	public int getCurrTempoMPQ() {
	return currTempo;
	}

	float getTempoMPQAt(long tick) {
	return getTempoMPQAt(tick, -1.0f);
	}

	synchronized float getTempoMPQAt(long tick, float startTempoMPQ) {
	for (int i = 0; i < ticks.length; i++) {
	if (ticks[i] > tick) {
	if (i > 0) i--;
	if (startTempoMPQ > 0 && i == 0 && firstTempoIsFake) {
	return startTempoMPQ;
	}
	return (float) tempos[i];
	}
	}
	return tempos[tempos.length - 1];
	}

	}
	}

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