| /* MetaMessage.java -- A meta message for MIDI files. |
| Copyright (C) 2005 Free Software Foundation, Inc. |
| |
| This file is part of GNU Classpath. |
| |
| GNU Classpath 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, or (at your option) |
| any later version. |
| |
| GNU Classpath 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 GNU Classpath; see the file COPYING. If not, write to the |
| Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA |
| 02110-1301 USA. |
| |
| Linking this library statically or dynamically with other modules is |
| making a combined work based on this library. Thus, the terms and |
| conditions of the GNU General Public License cover the whole |
| combination. |
| |
| As a special exception, the copyright holders of this library give you |
| permission to link this library with independent modules to produce an |
| executable, regardless of the license terms of these independent |
| modules, and to copy and distribute the resulting executable under |
| terms of your choice, provided that you also meet, for each linked |
| independent module, the terms and conditions of the license of that |
| module. An independent module is a module which is not derived from |
| or based on this library. If you modify this library, you may extend |
| this exception to your version of the library, but you are not |
| obligated to do so. If you do not wish to do so, delete this |
| exception statement from your version. */ |
| |
| |
| package javax.sound.midi; |
| |
| /** |
| * A system exclusive MIDI message. |
| * |
| * @author Anthony Green (green@redhat.com) |
| * @since 1.3 |
| * |
| */ |
| public class MetaMessage extends MidiMessage |
| { |
| /** |
| * The META status code. Only valid for MIDI files, not the wire protocol. |
| */ |
| public static final int META = 0xFF; |
| |
| // The length of the variable length data length encoding. |
| private int lengthLength = 0; |
| |
| /** |
| * Create a default valid meta message. |
| * |
| * The official specs don't specify what message is to be |
| * created. For now, we create a zero length meta message |
| * with a type code of 0. |
| */ |
| public MetaMessage() |
| { |
| super(new byte[4]); |
| data[0] = (byte) META; |
| data[1] = (byte) 0; // Type |
| data[2] = (byte) 1; // Length length |
| data[3] = (byte) 0; // Length |
| lengthLength = 1; |
| } |
| |
| /** |
| * Create a MetaMessage object. |
| * @param data a complete system exclusive message |
| */ |
| protected MetaMessage(byte[] data) |
| { |
| super(data); |
| int index = 2; |
| lengthLength = 1; |
| while ((data[index++] & 0x80) > 0) |
| lengthLength++; |
| } |
| |
| /** |
| * Set the meta message. |
| * |
| * @param type the meta type byte (< 128) |
| * @param data the message data |
| * @param length the length of the message data |
| * @throws InvalidMidiDataException if this message is invalid |
| */ |
| public void setMessage(int type, byte[] data, int length) |
| throws InvalidMidiDataException |
| { |
| if (type > 127) |
| throw new InvalidMidiDataException("Meta type 0x" |
| + Integer.toHexString(type) |
| + " must be less than 128"); |
| |
| // For a nice description of how variable length values are handled, |
| // see http://www.borg.com/~jglatt/tech/midifile.htm |
| |
| // First compute the length of the length value |
| lengthLength = 0; |
| int lengthValue = length; |
| do { |
| lengthValue = lengthValue >> 7; |
| lengthLength++; |
| } while (lengthValue > 0); |
| |
| // Now allocate our data array |
| this.length = 2 + lengthLength + length; |
| this.data = new byte[this.length]; |
| this.data[0] = (byte) META; |
| this.data[1] = (byte) type; |
| |
| // Now compute the length representation |
| long buffer = length & 0x7F; |
| // Avoid altering length variable; PR42551 |
| lengthValue = length; |
| while ((lengthValue >>= 7) > 0) |
| { |
| buffer <<= 8; |
| buffer |= ((lengthValue & 0x7F) | 0x80); |
| } |
| |
| // Now store the variable length length value |
| int index = 2; |
| do |
| { |
| this.data[index++] = (byte) (buffer & 0xFF); |
| if ((buffer & 0x80) == 0) |
| break; |
| buffer >>= 8; |
| } while (true); |
| |
| // Now copy the real data. |
| System.arraycopy(data, 0, this.data, index, length); |
| } |
| |
| /** |
| * Get the meta message type. |
| * |
| * @return the meta message type |
| */ |
| public int getType() |
| { |
| return data[1]; |
| } |
| |
| /** |
| * Get the data for this message, not including the status, |
| * type, or length information. |
| * |
| * @return the message data, not including status, type or lenght info |
| */ |
| public byte[] getData() |
| { |
| int dataLength = length - 2 - lengthLength; |
| byte[] result = new byte[dataLength]; |
| System.arraycopy(data, 2 + lengthLength, result, 0, dataLength); |
| return result; |
| } |
| |
| /* Create a deep-copy clone of this object. |
| * @see java.lang.Object#clone() |
| */ |
| public Object clone() |
| { |
| byte message[] = new byte[length]; |
| System.arraycopy(data, 0, message, 0, length); |
| return new MetaMessage(message); |
| } |
| } |