jm.midi.event.TempoEvent Maven / Gradle / Ivy

Go to download
Show more of this group Show more artifacts with this name
Show all versions of jmusic Show documentation
JMusic - Java Music Library
The newest version!
/*

:56  2001

Copyright (C) 2000 Andrew Sorensen & Andrew Brown

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 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., 675 Mass Ave, Cambridge, MA 02139, USA.

*/

package jm.midi.event;

import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.IOException;

/**
 * TempoEvent Events are contained in the MidiFile class's tempoList
 * unlike most of the other events which are track data stored in
 * the track Event List.
 *
 * @author Andrew Sorensen
 */

public final class TempoEvent implements Event {
    private short id = 020;
    private int time = 0;
    private double tempo = 60.0;

    //------------------------------------------
    //Constructors

    /**
     * Default Constructor
     */
    public TempoEvent() {
        this(0, 0.0);
    }

    public TempoEvent(double tempo) {
        this(0, tempo);
    }

    public TempoEvent(int time, double tempo) {
        this.time = time;
        this.tempo = tempo;
    }
    //--------------------------------------------
    //TempoEvent

    /**
     * Returns a tempo value
     */
    public double getTempo() {
        return tempo;
    }

    /**
     * Sets the tempo events tempo field
     */
    public void setTempo(double tempo) {
        this.tempo = tempo;
    }

    //-----------------------------------------------

    /**
     * return time
     */
    public int getTime() {
        return time;
    }

    /**
     * Specify the time
     */
    public void setTime(int time) {
        this.time = time;
    }

    //----------------------------------------------

    /**
     * Return Id
     */
    public short getID() {
        return id;
    }

    //----------------------------------------------

    /**
     * Write the contents of this object out to disk
     */
    //----------------------------------------------
    public int write(DataOutputStream dos) throws IOException {
        int bytes_out = jm.midi.MidiUtil.writeVarLength(this.time, dos);
        dos.writeByte((byte) 0xFF); //META Event Type
        dos.writeByte((byte) 0x51); //TempoEvent Event Type
        bytes_out += jm.midi.MidiUtil.writeVarLength(3, dos);
        int temp = (int) (((float) 60 / (float) this.tempo) * (float) 1000000);
        dos.writeByte((byte) (((temp >> 16) & 255)));
        dos.writeByte((byte) (((temp >> 8) & 255)));
        dos.writeByte((byte) ((temp & 255)));
        return bytes_out + 5;
    }

    //----------------------------------------------

    /**
     * Read the contends of this object in from disk
     */
    public int read(DataInputStream dis) throws IOException {
        int b1 = (int) dis.readUnsignedByte();
        int b2 = (int) dis.readUnsignedByte();
        int b3 = (int) dis.readUnsignedByte();
        int temp = (b1 << 16) + (b2 << 8) + b3;
        this.tempo = (double) (1000000f / (float) temp * 60.0f);
        return 3;
    }

    /**
     * Copy Object
     */
    public Event copy() throws CloneNotSupportedException {
        TempoEvent event;
        try {
            event = (TempoEvent) this.clone();
        } catch (CloneNotSupportedException e) {
            System.out.println(e);
            event = new TempoEvent();
        }
        return event;
    }
    //---------------------------------------------------

    /**
     * Print data
     */
    public void print() {
        System.out.println("TempoEvent(020):             [time = " + this.time + "][tempo = " + this.tempo + "]");
    }
}