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+/* 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;
+ while ((length >>= 7) > 0)
+ {
+ buffer <<= 8;
+ buffer |= ((length & 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);
+ }
+}