| /* |
| * Copyright (c) 1999, 2003, 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 javax.sound.midi; |
| |
| import java.io.ByteArrayOutputStream; |
| import java.io.DataOutputStream; |
| import java.io.IOException; |
| |
| |
| /** |
| * A <code>MetaMessage</code> is a <code>{@link MidiMessage}</code> that is not meaningful to synthesizers, but |
| * that can be stored in a MIDI file and interpreted by a sequencer program. |
| * (See the discussion in the <code>MidiMessage</code> |
| * class description.) The Standard MIDI Files specification defines |
| * various types of meta-events, such as sequence number, lyric, cue point, |
| * and set tempo. There are also meta-events |
| * for such information as lyrics, copyrights, tempo indications, time and key |
| * signatures, markers, etc. For more information, see the Standard MIDI Files 1.0 |
| * specification, which is part of the Complete MIDI 1.0 Detailed Specification |
| * published by the MIDI Manufacturer's Association |
| * (<a href = http://www.midi.org>http://www.midi.org</a>). |
| * |
| * <p> |
| * When data is being transported using MIDI wire protocol, |
| * a <code>{@link ShortMessage}</code> with the status value <code>0xFF</code> represents |
| * a system reset message. In MIDI files, this same status value denotes a <code>MetaMessage</code>. |
| * The types of meta-message are distinguished from each other by the first byte |
| * that follows the status byte <code>0xFF</code>. The subsequent bytes are data |
| * bytes. As with system exclusive messages, there are an arbitrary number of |
| * data bytes, depending on the type of <code>MetaMessage</code>. |
| * |
| * @see MetaEventListener |
| * |
| * @author David Rivas |
| * @author Kara Kytle |
| */ |
| |
| public class MetaMessage extends MidiMessage { |
| |
| |
| // Status byte defines |
| |
| /** |
| * Status byte for <code>MetaMessage</code> (0xFF, or 255), which is used |
| * in MIDI files. It has the same value as SYSTEM_RESET, which |
| * is used in the real-time "MIDI wire" protocol. |
| * @see MidiMessage#getStatus |
| */ |
| public static final int META = 0xFF; // 255 |
| |
| |
| // Default meta message data: just the META status byte value |
| // $$kk: 09.09.99: need a real event here!! |
| |
| private static byte[] defaultMessage = { (byte)META, 0 }; |
| |
| |
| |
| // Instance variables |
| |
| /** |
| * The length of the actual message in the data array. |
| * This is used to determine how many bytes of the data array |
| * is the message, and how many are the status byte, the |
| * type byte, and the variable-length-int describing the |
| * length of the message. |
| */ |
| private int dataLength = 0; |
| |
| |
| /** |
| * Constructs a new <code>MetaMessage</code>. The contents of |
| * the message are not set here; use |
| * {@link #setMessage(int, byte[], int) setMessage} |
| * to set them subsequently. |
| */ |
| public MetaMessage() { |
| //super(defaultMessage); |
| this(defaultMessage); |
| } |
| |
| /** |
| * Constructs a new {@code MetaMessage} and sets the message parameters. |
| * The contents of the message can be changed by using |
| * the {@code setMessage} method. |
| * |
| * @param type meta-message type (must be less than 128) |
| * @param data the data bytes in the MIDI message |
| * @param length an amount of bytes in the {@code data} byte array; |
| * it should be non-negative and less than or equal to |
| * {@code data.length} |
| * @throws InvalidMidiDataException if the parameter values do not specify |
| * a valid MIDI meta message |
| * @see #setMessage(int, byte[], int) |
| * @see #getType() |
| * @see #getData() |
| * @since 1.7 |
| */ |
| public MetaMessage(int type, byte[] data, int length) |
| throws InvalidMidiDataException { |
| super(null); |
| setMessage(type, data, length); // can throw InvalidMidiDataException |
| } |
| |
| |
| /** |
| * Constructs a new <code>MetaMessage</code>. |
| * @param data an array of bytes containing the complete message. |
| * The message data may be changed using the <code>setMessage</code> |
| * method. |
| * @see #setMessage |
| */ |
| protected MetaMessage(byte[] data) { |
| super(data); |
| //$$fb 2001-10-06: need to calculate dataLength. Fix for bug #4511796 |
| if (data.length>=3) { |
| dataLength=data.length-3; |
| int pos=2; |
| while (pos<data.length && (data[pos] & 0x80)!=0) { |
| dataLength--; pos++; |
| } |
| } |
| } |
| |
| |
| /** |
| * Sets the message parameters for a <code>MetaMessage</code>. |
| * Since only one status byte value, <code>0xFF</code>, is allowed for meta-messages, |
| * it does not need to be specified here. Calls to <code>{@link MidiMessage#getStatus getStatus}</code> return |
| * <code>0xFF</code> for all meta-messages. |
| * <p> |
| * The <code>type</code> argument should be a valid value for the byte that |
| * follows the status byte in the <code>MetaMessage</code>. The <code>data</code> argument |
| * should contain all the subsequent bytes of the <code>MetaMessage</code>. In other words, |
| * the byte that specifies the type of <code>MetaMessage</code> is not considered a data byte. |
| * |
| * @param type meta-message type (must be less than 128) |
| * @param data the data bytes in the MIDI message |
| * @param length the number of bytes in the <code>data</code> |
| * byte array |
| * @throws <code>InvalidMidiDataException</code> if the |
| * parameter values do not specify a valid MIDI meta message |
| */ |
| public void setMessage(int type, byte[] data, int length) throws InvalidMidiDataException { |
| |
| if (type >= 128 || type < 0) { |
| throw new InvalidMidiDataException("Invalid meta event with type " + type); |
| } |
| if ((length > 0 && length > data.length) || length < 0) { |
| throw new InvalidMidiDataException("length out of bounds: "+length); |
| } |
| |
| this.length = 2 + getVarIntLength(length) + length; |
| this.dataLength = length; |
| this.data = new byte[this.length]; |
| this.data[0] = (byte) META; // status value for MetaMessages (meta events) |
| this.data[1] = (byte) type; // MetaMessage type |
| writeVarInt(this.data, 2, length); // write the length as a variable int |
| if (length > 0) { |
| System.arraycopy(data, 0, this.data, this.length - this.dataLength, this.dataLength); |
| } |
| } |
| |
| |
| /** |
| * Obtains the type of the <code>MetaMessage</code>. |
| * @return an integer representing the <code>MetaMessage</code> type |
| */ |
| public int getType() { |
| if (length>=2) { |
| return data[1] & 0xFF; |
| } |
| return 0; |
| } |
| |
| |
| |
| /** |
| * Obtains a copy of the data for the meta message. The returned |
| * array of bytes does not include the status byte or the message |
| * length data. The length of the data for the meta message is |
| * the length of the array. Note that the length of the entire |
| * message includes the status byte and the meta message type |
| * byte, and therefore may be longer than the returned array. |
| * @return array containing the meta message data. |
| * @see MidiMessage#getLength |
| */ |
| public byte[] getData() { |
| byte[] returnedArray = new byte[dataLength]; |
| System.arraycopy(data, (length - dataLength), returnedArray, 0, dataLength); |
| return returnedArray; |
| } |
| |
| |
| /** |
| * Creates a new object of the same class and with the same contents |
| * as this object. |
| * @return a clone of this instance |
| */ |
| public Object clone() { |
| byte[] newData = new byte[length]; |
| System.arraycopy(data, 0, newData, 0, newData.length); |
| |
| MetaMessage event = new MetaMessage(newData); |
| return event; |
| } |
| |
| // HELPER METHODS |
| |
| private int getVarIntLength(long value) { |
| int length = 0; |
| do { |
| value = value >> 7; |
| length++; |
| } while (value > 0); |
| return length; |
| } |
| |
| private final static long mask = 0x7F; |
| |
| private void writeVarInt(byte[] data, int off, long value) { |
| int shift=63; // number of bitwise left-shifts of mask |
| // first screen out leading zeros |
| while ((shift > 0) && ((value & (mask << shift)) == 0)) shift-=7; |
| // then write actual values |
| while (shift > 0) { |
| data[off++]=(byte) (((value & (mask << shift)) >> shift) | 0x80); |
| shift-=7; |
| } |
| data[off] = (byte) (value & mask); |
| } |
| |
| } |
