content: /*
   * Copyright (c) 1999, 2003, Oracle and/or its affiliates. All rights reserved.
   * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
   *
   *
   *
   *
   *
   *
   *
   *
   *
   *
   *
   *
   *
   *
   *
   *
   *
   *
   *
   *
   */
  
  package lib.sound.midi;
  
  /**
   * 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/>
   * <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>.
   *
   * @author David Rivas
   * @author Kara Kytle
   * @see MetaEventListener
   */
  
  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 final static long mask = 0x7F;
  
  
      // Instance variables
      private static byte[] defaultMessage = {(byte) META, 0};
      /**
       * 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;
      }
  
      // HELPER METHODS
  
      /**
       * 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;
      }
  
      private int getVarIntLength(long value) {
          int length = 0;
          do {
              value = value >> 7;
              length++;
          } while (value > 0);
          return length;
      }
  
      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);
      }
  
  }
  