Source for javax.sound.midi.ShortMessage

   1: /* ShortMessage.java -- A MIDI message no longer than 3 bytes
   2:    Copyright (C) 2005 Free Software Foundation, Inc.
   3: 
   4: This file is part of GNU Classpath.
   5: 
   6: GNU Classpath is free software; you can redistribute it and/or modify
   7: it under the terms of the GNU General Public License as published by
   8: the Free Software Foundation; either version 2, or (at your option)
   9: any later version.
  10: 
  11: GNU Classpath is distributed in the hope that it will be useful, but
  12: WITHOUT ANY WARRANTY; without even the implied warranty of
  13: MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14: General Public License for more details.
  15: 
  16: You should have received a copy of the GNU General Public License
  17: along with GNU Classpath; see the file COPYING.  If not, write to the
  18: Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
  19: 02110-1301 USA.
  20: 
  21: Linking this library statically or dynamically with other modules is
  22: making a combined work based on this library.  Thus, the terms and
  23: conditions of the GNU General Public License cover the whole
  24: combination.
  25: 
  26: As a special exception, the copyright holders of this library give you
  27: permission to link this library with independent modules to produce an
  28: executable, regardless of the license terms of these independent
  29: modules, and to copy and distribute the resulting executable under
  30: terms of your choice, provided that you also meet, for each linked
  31: independent module, the terms and conditions of the license of that
  32: module.  An independent module is a module which is not derived from
  33: or based on this library.  If you modify this library, you may extend
  34: this exception to your version of the library, but you are not
  35: obligated to do so.  If you do not wish to do so, delete this
  36: exception statement from your version. */
  37: 
  38: 
  39: package javax.sound.midi;
  40: 
  41: /**
  42:  * A short MIDI message that is no longer than 3 bytes long.
  43:  *
  44:  * @author Anthony Green (green@redhat.com)
  45:  * @since 1.3
  46:  *
  47:  */
  48: public class ShortMessage extends MidiMessage
  49: {
  50:   /**
  51:    * Status byte for Time Code message.
  52:    */
  53:   public static final int MIDI_TIME_CODE = 0xF1;
  54: 
  55:   /**
  56:    * Status byte for Song Position Pointer message.
  57:    */
  58:   public static final int SONG_POSITION_POINTER = 0xF2;
  59: 
  60:   /**
  61:    * Status byte for Song Select message.
  62:    */
  63:   public static final int SONG_SELECT = 0xF3;
  64: 
  65:   /**
  66:    * Status byte for Tune Request message.
  67:    */
  68:   public static final int TUNE_REQUEST = 0xF6;
  69: 
  70:   /**
  71:    * Status byte for End Of Exclusive message.
  72:    */
  73:   public static final int END_OF_EXCLUSIVE = 0xF7;
  74: 
  75:   /**
  76:    * Status byte for Timing Clock message.
  77:    */
  78:   public static final int TIMING_CLOCK = 0xF8;
  79: 
  80:   /**
  81:    * Status byte for Start message.
  82:    */
  83:   public static final int START = 0xFA;
  84: 
  85:   /**
  86:    * Status byte for Continue message.
  87:    */
  88:   public static final int CONTINUE = 0xFB;
  89: 
  90:   /**
  91:    * Status byte for Stop message.
  92:    */
  93:   public static final int STOP = 0xFC;
  94: 
  95:   /**
  96:    * Status byte for Active Sensing message.
  97:    */
  98:   public static final int ACTIVE_SENSING = 0xFE;
  99: 
 100:   /**
 101:    * Status byte for System Reset message.
 102:    */
 103:   public static final int SYSTEM_RESET = 0xFF;
 104: 
 105:   /**
 106:    * Status nibble for Note Off message.
 107:    */
 108:   public static final int NOTE_OFF = 0x80;
 109: 
 110:   /**
 111:    * Status nibble for Note On message.
 112:    */
 113:   public static final int NOTE_ON = 0x90;
 114: 
 115:   /**
 116:    * Status nibble for Poly Pressure message.
 117:    */
 118:   public static final int POLY_PRESSURE = 0xA0;
 119: 
 120:   /**
 121:    * Status nibble for Control Change message.
 122:    */
 123:   public static final int CONTROL_CHANGE = 0xB0;
 124: 
 125:   /**
 126:    * Status nibble for Program Change message.
 127:    */
 128:   public static final int PROGRAM_CHANGE = 0xC0;
 129: 
 130:   /**
 131:    * Statue nibble for Channel Pressure message.
 132:    */
 133:   public static final int CHANNEL_PRESSURE = 0xD0;
 134: 
 135:   /**
 136:    * Status nibble for Pitch Bend message.
 137:    */
 138:   public static final int PITCH_BEND = 0xE0;
 139: 
 140:   // Create and initialize a default, arbitrary message.
 141:   private static byte[] defaultMessage;
 142:   static
 143:   {
 144:     defaultMessage = new byte[1];
 145:     defaultMessage[0] = (byte) STOP;
 146:   }
 147: 
 148:   /**
 149:    * Create a short MIDI message.
 150:    *
 151:    * The spec requires that this represent a valid MIDI message, but doesn't
 152:    * specify what it should be.  We've chosen the STOP message for our
 153:    * implementation.
 154:    */
 155:   public ShortMessage()
 156:   {
 157:     this(defaultMessage);
 158:   }
 159: 
 160:   /**
 161:    * Create a short MIDI message.
 162:    *
 163:    * The data argument should be a valid MIDI message.  Unfortunately the spec
 164:    * does not allow us to throw an InvalidMidiDataException if data is invalid.
 165:    *
 166:    * @param data the message data
 167:    */
 168:   protected ShortMessage(byte[] data)
 169:   {
 170:     super(data);
 171:   }
 172: 
 173:   /**
 174:    * Set the MIDI message.
 175:    *
 176:    * @param status the status byte for this message
 177:    * @param data1 the first data byte for this message
 178:    * @param data2 the second data byte for this message
 179:    * @throws InvalidMidiDataException if status is bad, or data is out of range
 180:    */
 181:   public void setMessage(int status, int data1, int data2)
 182:     throws InvalidMidiDataException
 183:   {
 184:     length = getDataLength(status);
 185:     length++;
 186:     if (data == null || data.length < length)
 187:       data = new byte[length];
 188:     data[0] = (byte) status;
 189:     if (length > 1)
 190:     {
 191:       if (data1 < 0 || data1 > 127)
 192:         throw new InvalidMidiDataException("data1 (" + data1
 193:                                            + ") must be between 0 and 127.");
 194:       data[1] = (byte) data1;
 195:       if (length > 2)
 196:       {
 197:         if (data2 < 0 || data2 > 127)
 198:           throw new InvalidMidiDataException("data2 (" + data2
 199:                                              + ") must be between 0 and 127.");
 200:         data[2] = (byte) data2;
 201:       }
 202:     }
 203:   }
 204: 
 205:   public void setMessage(int command, int channel, int data1, int data2)
 206:     throws InvalidMidiDataException
 207:   {
 208:     // TODO: This could probably stand some error checking.
 209:     // It currently assumes command and channel are valid values.
 210:     setMessage(command + channel, data1, data2);
 211:   }
 212: 
 213:   /**
 214:    * Set the MIDI message to one that requires no data bytes.
 215:    *
 216:    * @param status the status byte for this message
 217:    * @throws InvalidMidiDataException if status is bad, or requires data
 218:    */
 219:   public void setMessage(int status) throws InvalidMidiDataException
 220:   {
 221:     int length = getDataLength(status);
 222:     if (length != 0)
 223:       throw new InvalidMidiDataException("Status byte 0x"
 224:                                          + Integer.toHexString(status)
 225:                                          + " requires "
 226:                                          + length + " bytes of data.");
 227:     setMessage(status, 0, 0);
 228:   }
 229: 
 230: 
 231:   /**
 232:    * Return the number of data bytes needed for a given MIDI status byte.
 233:    *
 234:    * @param status the status byte for a short MIDI message
 235:    * @return the number of data bytes needed for this status byte
 236:    * @throws InvalidMidiDataException if status is an invalid status byte
 237:    */
 238:   protected final int getDataLength(int status) throws InvalidMidiDataException
 239:   {
 240:     int originalStatus = status;
 241: 
 242:     if ((status & 0xF0) != 0xF0)
 243:       status &= 0xF0;
 244: 
 245:     switch (status)
 246:     {
 247:     case NOTE_OFF:
 248:     case NOTE_ON:
 249:     case POLY_PRESSURE:
 250:     case CONTROL_CHANGE:
 251:     case PITCH_BEND:
 252:     case SONG_POSITION_POINTER:
 253:       return 2;
 254: 
 255:     case PROGRAM_CHANGE:
 256:     case CHANNEL_PRESSURE:
 257:     case SONG_SELECT:
 258:     case 0xF5:  // FIXME: unofficial bus select.  Not in spec??
 259:       return 1;
 260: 
 261:     case TUNE_REQUEST:
 262:     case END_OF_EXCLUSIVE:
 263:     case TIMING_CLOCK:
 264:     case START:
 265:     case CONTINUE:
 266:     case STOP:
 267:     case ACTIVE_SENSING:
 268:     case SYSTEM_RESET:
 269:       return 0;
 270: 
 271:     default:
 272:       throw new InvalidMidiDataException("Invalid status: 0x"
 273:                                          + Integer.toHexString(originalStatus));
 274:     }
 275:   }
 276: 
 277:   /**
 278:    * Get the channel information from this MIDI message, assuming it is a
 279:    * MIDI channel message.
 280:    *
 281:    * @return the MIDI channel for this message
 282:    */
 283:   public int getChannel()
 284:   {
 285:     return data[0] & 0x0F;
 286:   }
 287: 
 288:   /**
 289:    * Get the command nibble from this MIDI message, assuming it is a MIDI
 290:    * channel message.
 291:    *
 292:    * @return the MIDI command for this message
 293:    */
 294:   public int getCommand()
 295:   {
 296:     return data[0] & 0xF0;
 297:   }
 298: 
 299:   /**
 300:    * Get the first data byte from this message, assuming it exists, and
 301:    * zero otherwise.
 302:    *
 303:    * @return the first data byte or zero if none exists.
 304:    */
 305:   public int getData1()
 306:   {
 307:     if (length > 1)
 308:       return data[1];
 309:     else
 310:       return 0;
 311:   }
 312: 
 313:   /**
 314:    * Get the second data byte from this message, assuming it exists, and
 315:    * zero otherwise.
 316:    *
 317:    * @return the second date byte or zero if none exists.
 318:    */
 319:   public int getData2()
 320:   {
 321:     if (length > 2)
 322:       return data[2];
 323:     else
 324:       return 0;
 325:   }
 326: 
 327:   /* Create a deep-copy clone of this object.
 328:    * @see java.lang.Object#clone()
 329:    */
 330:   public Object clone()
 331:   {
 332:     byte message[] = new byte[length];
 333:     System.arraycopy(data, 0, message, 0, length);
 334:     return new ShortMessage(message);
 335:   }
 336: }