001 /* ShortMessage.java -- A MIDI message no longer than 3 bytes
002 Copyright (C) 2005 Free Software Foundation, Inc.
003
004 This file is part of GNU Classpath.
005
006 GNU Classpath is free software; you can redistribute it and/or modify
007 it under the terms of the GNU General Public License as published by
008 the Free Software Foundation; either version 2, or (at your option)
009 any later version.
010
011 GNU Classpath is distributed in the hope that it will be useful, but
012 WITHOUT ANY WARRANTY; without even the implied warranty of
013 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
014 General Public License for more details.
015
016 You should have received a copy of the GNU General Public License
017 along with GNU Classpath; see the file COPYING. If not, write to the
018 Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
019 02110-1301 USA.
020
021 Linking this library statically or dynamically with other modules is
022 making a combined work based on this library. Thus, the terms and
023 conditions of the GNU General Public License cover the whole
024 combination.
025
026 As a special exception, the copyright holders of this library give you
027 permission to link this library with independent modules to produce an
028 executable, regardless of the license terms of these independent
029 modules, and to copy and distribute the resulting executable under
030 terms of your choice, provided that you also meet, for each linked
031 independent module, the terms and conditions of the license of that
032 module. An independent module is a module which is not derived from
033 or based on this library. If you modify this library, you may extend
034 this exception to your version of the library, but you are not
035 obligated to do so. If you do not wish to do so, delete this
036 exception statement from your version. */
037
038
039 package javax.sound.midi;
040
041 /**
042 * A short MIDI message that is no longer than 3 bytes long.
043 *
044 * @author Anthony Green (green@redhat.com)
045 * @since 1.3
046 *
047 */
048 public class ShortMessage extends MidiMessage
049 {
050 /**
051 * Status byte for Time Code message.
052 */
053 public static final int MIDI_TIME_CODE = 0xF1;
054
055 /**
056 * Status byte for Song Position Pointer message.
057 */
058 public static final int SONG_POSITION_POINTER = 0xF2;
059
060 /**
061 * Status byte for Song Select message.
062 */
063 public static final int SONG_SELECT = 0xF3;
064
065 /**
066 * Status byte for Tune Request message.
067 */
068 public static final int TUNE_REQUEST = 0xF6;
069
070 /**
071 * Status byte for End Of Exclusive message.
072 */
073 public static final int END_OF_EXCLUSIVE = 0xF7;
074
075 /**
076 * Status byte for Timing Clock message.
077 */
078 public static final int TIMING_CLOCK = 0xF8;
079
080 /**
081 * Status byte for Start message.
082 */
083 public static final int START = 0xFA;
084
085 /**
086 * Status byte for Continue message.
087 */
088 public static final int CONTINUE = 0xFB;
089
090 /**
091 * Status byte for Stop message.
092 */
093 public static final int STOP = 0xFC;
094
095 /**
096 * Status byte for Active Sensing message.
097 */
098 public static final int ACTIVE_SENSING = 0xFE;
099
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 }