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src/java.desktop/share/classes/com/sun/media/sound/UlawCodec.java

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  16  *
  17  * You should have received a copy of the GNU General Public License version
  18  * 2 along with this work; if not, write to the Free Software Foundation,
  19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  20  *
  21  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  22  * or visit www.oracle.com if you need additional information or have any
  23  * questions.
  24  */
  25 
  26 package com.sun.media.sound;
  27 
  28 import java.io.IOException;
  29 import java.util.Objects;
  30 import java.util.Vector;
  31 
  32 import javax.sound.sampled.AudioFormat;
  33 import javax.sound.sampled.AudioInputStream;
  34 import javax.sound.sampled.AudioSystem;
  35 
  36 
  37 /**
  38  * U-law encodes linear data, and decodes u-law data to linear data.
  39  *
  40  * @author Kara Kytle
  41  */
  42 public final class UlawCodec extends SunCodec {
  43 
  44     /* Tables used for U-law decoding */
  45 
  46     private static final byte[] ULAW_TABH = new byte[256];
  47     private static final byte[] ULAW_TABL = new byte[256];
  48 
  49     private static final AudioFormat.Encoding[] ulawEncodings = {AudioFormat.Encoding.ULAW,
  50                                                                  AudioFormat.Encoding.PCM_SIGNED};
  51 
  52     private static final short seg_end [] = {0xFF, 0x1FF, 0x3FF,
  53                                              0x7FF, 0xFFF, 0x1FFF, 0x3FFF, 0x7FFF};
  54 
  55     /**
  56      * Initializes the decode tables
  57      */
  58     static {
  59         for (int i=0;i<256;i++) {
  60             int ulaw = ~i;
  61             int t;
  62 
  63             ulaw &= 0xFF;
  64             t = ((ulaw & 0xf)<<3) + 132;
  65             t <<= ((ulaw & 0x70) >> 4);
  66             t = ( (ulaw&0x80) != 0 ) ? (132-t) : (t-132);
  67 
  68             ULAW_TABL[i] = (byte) (t&0xff);
  69             ULAW_TABH[i] = (byte) ((t>>8) & 0xff);
  70         }
  71     }
  72 
  73 
  74     /**
  75      * Constructs a new ULAW codec object.
  76      */
  77     public UlawCodec() {
  78         super(ulawEncodings, ulawEncodings);
  79     }
  80 
  81     /**
  82      */
  83     public AudioFormat.Encoding[] getTargetEncodings(AudioFormat sourceFormat){
  84         if( AudioFormat.Encoding.PCM_SIGNED.equals(sourceFormat.getEncoding()) ) {
  85             if( sourceFormat.getSampleSizeInBits() == 16 ) {
  86                 AudioFormat.Encoding enc[] = new AudioFormat.Encoding[1];
  87                 enc[0] = AudioFormat.Encoding.ULAW;
  88                 return enc;
  89             } else {
  90                 return new AudioFormat.Encoding[0];
  91             }
  92         } else if (AudioFormat.Encoding.ULAW.equals(sourceFormat.getEncoding())) {
  93             if (sourceFormat.getSampleSizeInBits() == 8) {
  94                 AudioFormat.Encoding enc[] = new AudioFormat.Encoding[1];
  95                 enc[0] = AudioFormat.Encoding.PCM_SIGNED;
  96                 return enc;
  97             } else {
  98                 return new AudioFormat.Encoding[0];
  99             }
 100         } else {
 101             return new AudioFormat.Encoding[0];
 102         }
 103     }
 104 
 105 
 106     /**
 107      */
 108     public AudioFormat[] getTargetFormats(AudioFormat.Encoding targetEncoding, AudioFormat sourceFormat){
 109         Objects.requireNonNull(targetEncoding);
 110         Objects.requireNonNull(sourceFormat);
 111         if( (AudioFormat.Encoding.PCM_SIGNED.equals(targetEncoding)
 112              && AudioFormat.Encoding.ULAW.equals(sourceFormat.getEncoding()))
 113             ||
 114             (AudioFormat.Encoding.ULAW.equals(targetEncoding)
 115              && AudioFormat.Encoding.PCM_SIGNED.equals(sourceFormat.getEncoding()))) {
 116                 return getOutputFormats(sourceFormat);
 117             } else {
 118                 return new AudioFormat[0];
 119             }
 120     }
 121 
 122     /**
 123      */
 124     public AudioInputStream getAudioInputStream(AudioFormat.Encoding targetEncoding, AudioInputStream sourceStream){
 125         AudioFormat sourceFormat = sourceStream.getFormat();
 126         AudioFormat.Encoding sourceEncoding = sourceFormat.getEncoding();
 127 
 128         if (!isConversionSupported(targetEncoding,sourceStream.getFormat())) {
 129             throw new IllegalArgumentException("Unsupported conversion: " + sourceStream.getFormat().toString() + " to " + targetEncoding.toString());
 130         }
 131         if (sourceEncoding.equals(targetEncoding)) {
 132             return sourceStream;
 133         }
 134         AudioFormat targetFormat = null;
 135         if (AudioFormat.Encoding.ULAW.equals(sourceEncoding) &&
 136             AudioFormat.Encoding.PCM_SIGNED.equals(targetEncoding) ) {
 137             targetFormat = new AudioFormat( targetEncoding,
 138                                             sourceFormat.getSampleRate(),
 139                                             16,
 140                                             sourceFormat.getChannels(),
 141                                             2*sourceFormat.getChannels(),
 142                                             sourceFormat.getSampleRate(),
 143                                             sourceFormat.isBigEndian());
 144         } else if (AudioFormat.Encoding.PCM_SIGNED.equals(sourceEncoding) &&
 145                    AudioFormat.Encoding.ULAW.equals(targetEncoding)) {
 146             targetFormat = new AudioFormat( targetEncoding,
 147                                             sourceFormat.getSampleRate(),
 148                                             8,
 149                                             sourceFormat.getChannels(),
 150                                             sourceFormat.getChannels(),
 151                                             sourceFormat.getSampleRate(),
 152                                             false);
 153         } else {
 154             throw new IllegalArgumentException("Unsupported conversion: " + sourceStream.getFormat().toString() + " to " + targetEncoding.toString());
 155         }
 156 
 157         return getConvertedStream(targetFormat, sourceStream);
 158     }
 159 
 160     /**
 161      * use old code...
 162      */
 163     public AudioInputStream getAudioInputStream(AudioFormat targetFormat, AudioInputStream sourceStream){
 164         if (!isConversionSupported(targetFormat, sourceStream.getFormat()))
 165             throw new IllegalArgumentException("Unsupported conversion: "
 166                                                + sourceStream.getFormat().toString() + " to "
 167                                                + targetFormat.toString());
 168         return getConvertedStream(targetFormat, sourceStream);
 169     }
 170 
 171 
 172     // OLD CODE
 173 
 174     /**
 175      * Opens the codec with the specified parameters.
 176      * @param stream stream from which data to be processed should be read
 177      * @param outputFormat desired data format of the stream after processing
 178      * @return stream from which processed data may be read
 179      * @throws IllegalArgumentException if the format combination supplied is
 180      * not supported.
 181      */
 182     /*  public AudioInputStream getConvertedStream(AudioFormat outputFormat, AudioInputStream stream) { */
 183     private AudioInputStream getConvertedStream(AudioFormat outputFormat, AudioInputStream stream) {
 184         AudioInputStream cs = null;
 185 
 186         AudioFormat inputFormat = stream.getFormat();
 187 
 188         if( inputFormat.matches(outputFormat) ) {
 189             cs = stream;
 190         } else {
 191             cs = (AudioInputStream) (new UlawCodecStream(stream, outputFormat));
 192         }
 193         return cs;
 194     }
 195 
 196     /**
 197      * Obtains the set of output formats supported by the codec
 198      * given a particular input format.
 199      * If no output formats are supported for this input format,
 200      * returns an array of length 0.
 201      * @return array of supported output formats.
 202      */
 203     /*  public AudioFormat[] getOutputFormats(AudioFormat inputFormat) { */
 204     private AudioFormat[] getOutputFormats(AudioFormat inputFormat) {
 205 
 206         Vector<AudioFormat> formats = new Vector<>();
 207         AudioFormat format;
 208 
 209         if ((inputFormat.getSampleSizeInBits() == 16)
 210             && AudioFormat.Encoding.PCM_SIGNED.equals(inputFormat.getEncoding())) {
 211             format = new AudioFormat(AudioFormat.Encoding.ULAW,
 212                                      inputFormat.getSampleRate(),
 213                                      8,
 214                                      inputFormat.getChannels(),
 215                                      inputFormat.getChannels(),
 216                                      inputFormat.getSampleRate(),
 217                                      false );
 218             formats.addElement(format);
 219         }
 220         if (inputFormat.getSampleSizeInBits() == 8
 221                 && AudioFormat.Encoding.ULAW.equals(inputFormat.getEncoding())) {
 222             format = new AudioFormat(AudioFormat.Encoding.PCM_SIGNED,
 223                                      inputFormat.getSampleRate(), 16,
 224                                      inputFormat.getChannels(),
 225                                      inputFormat.getChannels() * 2,
 226                                      inputFormat.getSampleRate(), false);
 227             formats.addElement(format);
 228 
 229             format = new AudioFormat(AudioFormat.Encoding.PCM_SIGNED,
 230                                      inputFormat.getSampleRate(), 16,
 231                                      inputFormat.getChannels(),
 232                                      inputFormat.getChannels() * 2,
 233                                      inputFormat.getSampleRate(), true);
 234             formats.addElement(format);
 235         }
 236 
 237         AudioFormat[] formatArray = new AudioFormat[formats.size()];
 238         for (int i = 0; i < formatArray.length; i++) {
 239             formatArray[i] = formats.elementAt(i);
 240         }
 241         return formatArray;
 242     }
 243 
 244 
 245     private final class UlawCodecStream extends AudioInputStream {
 246 
 247         private static final int tempBufferSize = 64;
 248         private byte tempBuffer [] = null;
 249 
 250         /**
 251          * True to encode to u-law, false to decode to linear
 252          */
 253         boolean encode = false;
 254 
 255         AudioFormat encodeFormat;
 256         AudioFormat decodeFormat;
 257 
 258         byte tabByte1[] = null;
 259         byte tabByte2[] = null;
 260         int highByte = 0;
 261         int lowByte  = 1;
 262 
 263         UlawCodecStream(AudioInputStream stream, AudioFormat outputFormat) {
 264             super(stream, outputFormat, AudioSystem.NOT_SPECIFIED);
 265 
 266             AudioFormat inputFormat = stream.getFormat();
 267 
 268             // throw an IllegalArgumentException if not ok
 269             if (!(isConversionSupported(outputFormat, inputFormat))) {
 270                 throw new IllegalArgumentException("Unsupported conversion: " + inputFormat.toString() + " to " + outputFormat.toString());
 271             }


 295                 lowByte  = 1;
 296             } else {
 297                 tabByte1 = ULAW_TABL;
 298                 tabByte2 = ULAW_TABH;
 299                 highByte = 1;
 300                 lowByte  = 0;
 301             }
 302 
 303             // set the AudioInputStream length in frames if we know it
 304             if (stream instanceof AudioInputStream) {
 305                 frameLength = stream.getFrameLength();
 306             }
 307             // set framePos to zero
 308             framePos = 0;
 309             frameSize = inputFormat.getFrameSize();
 310             if (frameSize == AudioSystem.NOT_SPECIFIED) {
 311                 frameSize = 1;
 312             }
 313         }
 314 
 315 
 316         /*
 317          * $$jb 2/23/99
 318          * Used to determine segment number in uLaw encoding
 319          */
 320         private short search(short val, short table[], short size) {
 321             for(short i = 0; i < size; i++) {
 322                 if (val <= table[i]) { return i; }
 323             }
 324             return size;
 325         }
 326 
 327         /**
 328          * Note that this won't actually read anything; must read in
 329          * two-byte units.
 330          */

 331         public int read() throws IOException {
 332             byte[] b = new byte[1];
 333             if (read(b, 0, b.length) == 1) {
 334                 return b[1] & 0xFF;
 335             }
 336             return -1;
 337         }
 338 

 339         public int read(byte[] b) throws IOException {
 340             return read(b, 0, b.length);
 341         }
 342 

 343         public int read(byte[] b, int off, int len) throws IOException {
 344             // don't read fractional frames
 345             if( len%frameSize != 0 ) {
 346                 len -= (len%frameSize);
 347             }
 348             if (encode) {
 349                 short BIAS = 0x84;
 350                 short mask;
 351                 short seg;
 352                 int i;
 353 
 354                 short sample;
 355                 byte enc;
 356 
 357                 int readCount = 0;
 358                 int currentPos = off;
 359                 int readLeft = len*2;
 360                 int readLen = ( (readLeft>tempBufferSize) ? tempBufferSize : readLeft );
 361 
 362                 while ((readCount = super.read(tempBuffer,0,readLen))>0) {




  16  *
  17  * You should have received a copy of the GNU General Public License version
  18  * 2 along with this work; if not, write to the Free Software Foundation,
  19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  20  *
  21  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  22  * or visit www.oracle.com if you need additional information or have any
  23  * questions.
  24  */
  25 
  26 package com.sun.media.sound;
  27 
  28 import java.io.IOException;
  29 import java.util.Objects;
  30 import java.util.Vector;
  31 
  32 import javax.sound.sampled.AudioFormat;
  33 import javax.sound.sampled.AudioInputStream;
  34 import javax.sound.sampled.AudioSystem;
  35 

  36 /**
  37  * U-law encodes linear data, and decodes u-law data to linear data.
  38  *
  39  * @author Kara Kytle
  40  */
  41 public final class UlawCodec extends SunCodec {
  42 
  43     /* Tables used for U-law decoding */
  44 
  45     private static final byte[] ULAW_TABH = new byte[256];
  46     private static final byte[] ULAW_TABL = new byte[256];
  47 
  48     private static final AudioFormat.Encoding[] ulawEncodings = {AudioFormat.Encoding.ULAW,
  49                                                                  AudioFormat.Encoding.PCM_SIGNED};
  50 
  51     private static final short seg_end [] = {0xFF, 0x1FF, 0x3FF,
  52                                              0x7FF, 0xFFF, 0x1FFF, 0x3FFF, 0x7FFF};
  53 
  54     /**
  55      * Initializes the decode tables.
  56      */
  57     static {
  58         for (int i=0;i<256;i++) {
  59             int ulaw = ~i;
  60             int t;
  61 
  62             ulaw &= 0xFF;
  63             t = ((ulaw & 0xf)<<3) + 132;
  64             t <<= ((ulaw & 0x70) >> 4);
  65             t = ( (ulaw&0x80) != 0 ) ? (132-t) : (t-132);
  66 
  67             ULAW_TABL[i] = (byte) (t&0xff);
  68             ULAW_TABH[i] = (byte) ((t>>8) & 0xff);
  69         }
  70     }
  71 

  72     /**
  73      * Constructs a new ULAW codec object.
  74      */
  75     public UlawCodec() {
  76         super(ulawEncodings, ulawEncodings);
  77     }
  78 
  79     @Override

  80     public AudioFormat.Encoding[] getTargetEncodings(AudioFormat sourceFormat){
  81         if( AudioFormat.Encoding.PCM_SIGNED.equals(sourceFormat.getEncoding()) ) {
  82             if( sourceFormat.getSampleSizeInBits() == 16 ) {
  83                 AudioFormat.Encoding enc[] = new AudioFormat.Encoding[1];
  84                 enc[0] = AudioFormat.Encoding.ULAW;
  85                 return enc;
  86             } else {
  87                 return new AudioFormat.Encoding[0];
  88             }
  89         } else if (AudioFormat.Encoding.ULAW.equals(sourceFormat.getEncoding())) {
  90             if (sourceFormat.getSampleSizeInBits() == 8) {
  91                 AudioFormat.Encoding enc[] = new AudioFormat.Encoding[1];
  92                 enc[0] = AudioFormat.Encoding.PCM_SIGNED;
  93                 return enc;
  94             } else {
  95                 return new AudioFormat.Encoding[0];
  96             }
  97         } else {
  98             return new AudioFormat.Encoding[0];
  99         }
 100     }
 101 
 102     @Override


 103     public AudioFormat[] getTargetFormats(AudioFormat.Encoding targetEncoding, AudioFormat sourceFormat){
 104         Objects.requireNonNull(targetEncoding);
 105         Objects.requireNonNull(sourceFormat);
 106         if( (AudioFormat.Encoding.PCM_SIGNED.equals(targetEncoding)
 107              && AudioFormat.Encoding.ULAW.equals(sourceFormat.getEncoding()))
 108             ||
 109             (AudioFormat.Encoding.ULAW.equals(targetEncoding)
 110              && AudioFormat.Encoding.PCM_SIGNED.equals(sourceFormat.getEncoding()))) {
 111                 return getOutputFormats(sourceFormat);
 112             } else {
 113                 return new AudioFormat[0];
 114             }
 115     }
 116 
 117     @Override

 118     public AudioInputStream getAudioInputStream(AudioFormat.Encoding targetEncoding, AudioInputStream sourceStream){
 119         AudioFormat sourceFormat = sourceStream.getFormat();
 120         AudioFormat.Encoding sourceEncoding = sourceFormat.getEncoding();
 121 
 122         if (!isConversionSupported(targetEncoding,sourceStream.getFormat())) {
 123             throw new IllegalArgumentException("Unsupported conversion: " + sourceStream.getFormat().toString() + " to " + targetEncoding.toString());
 124         }
 125         if (sourceEncoding.equals(targetEncoding)) {
 126             return sourceStream;
 127         }
 128         AudioFormat targetFormat = null;
 129         if (AudioFormat.Encoding.ULAW.equals(sourceEncoding) &&
 130             AudioFormat.Encoding.PCM_SIGNED.equals(targetEncoding) ) {
 131             targetFormat = new AudioFormat( targetEncoding,
 132                                             sourceFormat.getSampleRate(),
 133                                             16,
 134                                             sourceFormat.getChannels(),
 135                                             2*sourceFormat.getChannels(),
 136                                             sourceFormat.getSampleRate(),
 137                                             sourceFormat.isBigEndian());
 138         } else if (AudioFormat.Encoding.PCM_SIGNED.equals(sourceEncoding) &&
 139                    AudioFormat.Encoding.ULAW.equals(targetEncoding)) {
 140             targetFormat = new AudioFormat( targetEncoding,
 141                                             sourceFormat.getSampleRate(),
 142                                             8,
 143                                             sourceFormat.getChannels(),
 144                                             sourceFormat.getChannels(),
 145                                             sourceFormat.getSampleRate(),
 146                                             false);
 147         } else {
 148             throw new IllegalArgumentException("Unsupported conversion: " + sourceStream.getFormat().toString() + " to " + targetEncoding.toString());
 149         }
 150 
 151         return getConvertedStream(targetFormat, sourceStream);
 152     }
 153 
 154     @Override


 155     public AudioInputStream getAudioInputStream(AudioFormat targetFormat, AudioInputStream sourceStream){
 156         if (!isConversionSupported(targetFormat, sourceStream.getFormat()))
 157             throw new IllegalArgumentException("Unsupported conversion: "
 158                                                + sourceStream.getFormat().toString() + " to "
 159                                                + targetFormat.toString());
 160         return getConvertedStream(targetFormat, sourceStream);
 161     }
 162 



 163     /**
 164      * Opens the codec with the specified parameters.
 165      * @param stream stream from which data to be processed should be read
 166      * @param outputFormat desired data format of the stream after processing
 167      * @return stream from which processed data may be read
 168      * @throws IllegalArgumentException if the format combination supplied is
 169      * not supported.
 170      */

 171     private AudioInputStream getConvertedStream(AudioFormat outputFormat, AudioInputStream stream) {
 172         AudioInputStream cs = null;
 173 
 174         AudioFormat inputFormat = stream.getFormat();
 175 
 176         if( inputFormat.matches(outputFormat) ) {
 177             cs = stream;
 178         } else {
 179             cs = new UlawCodecStream(stream, outputFormat);
 180         }
 181         return cs;
 182     }
 183 
 184     /**
 185      * Obtains the set of output formats supported by the codec
 186      * given a particular input format.
 187      * If no output formats are supported for this input format,
 188      * returns an array of length 0.
 189      * @return array of supported output formats.
 190      */

 191     private AudioFormat[] getOutputFormats(AudioFormat inputFormat) {
 192 
 193         Vector<AudioFormat> formats = new Vector<>();
 194         AudioFormat format;
 195 
 196         if ((inputFormat.getSampleSizeInBits() == 16)
 197             && AudioFormat.Encoding.PCM_SIGNED.equals(inputFormat.getEncoding())) {
 198             format = new AudioFormat(AudioFormat.Encoding.ULAW,
 199                                      inputFormat.getSampleRate(),
 200                                      8,
 201                                      inputFormat.getChannels(),
 202                                      inputFormat.getChannels(),
 203                                      inputFormat.getSampleRate(),
 204                                      false );
 205             formats.addElement(format);
 206         }
 207         if (inputFormat.getSampleSizeInBits() == 8
 208                 && AudioFormat.Encoding.ULAW.equals(inputFormat.getEncoding())) {
 209             format = new AudioFormat(AudioFormat.Encoding.PCM_SIGNED,
 210                                      inputFormat.getSampleRate(), 16,
 211                                      inputFormat.getChannels(),
 212                                      inputFormat.getChannels() * 2,
 213                                      inputFormat.getSampleRate(), false);
 214             formats.addElement(format);
 215 
 216             format = new AudioFormat(AudioFormat.Encoding.PCM_SIGNED,
 217                                      inputFormat.getSampleRate(), 16,
 218                                      inputFormat.getChannels(),
 219                                      inputFormat.getChannels() * 2,
 220                                      inputFormat.getSampleRate(), true);
 221             formats.addElement(format);
 222         }
 223 
 224         AudioFormat[] formatArray = new AudioFormat[formats.size()];
 225         for (int i = 0; i < formatArray.length; i++) {
 226             formatArray[i] = formats.elementAt(i);
 227         }
 228         return formatArray;
 229     }
 230 

 231     private final class UlawCodecStream extends AudioInputStream {
 232 
 233         private static final int tempBufferSize = 64;
 234         private byte tempBuffer [] = null;
 235 
 236         /**
 237          * True to encode to u-law, false to decode to linear.
 238          */
 239         boolean encode = false;
 240 
 241         AudioFormat encodeFormat;
 242         AudioFormat decodeFormat;
 243 
 244         byte tabByte1[] = null;
 245         byte tabByte2[] = null;
 246         int highByte = 0;
 247         int lowByte  = 1;
 248 
 249         UlawCodecStream(AudioInputStream stream, AudioFormat outputFormat) {
 250             super(stream, outputFormat, AudioSystem.NOT_SPECIFIED);
 251 
 252             AudioFormat inputFormat = stream.getFormat();
 253 
 254             // throw an IllegalArgumentException if not ok
 255             if (!(isConversionSupported(outputFormat, inputFormat))) {
 256                 throw new IllegalArgumentException("Unsupported conversion: " + inputFormat.toString() + " to " + outputFormat.toString());
 257             }


 281                 lowByte  = 1;
 282             } else {
 283                 tabByte1 = ULAW_TABL;
 284                 tabByte2 = ULAW_TABH;
 285                 highByte = 1;
 286                 lowByte  = 0;
 287             }
 288 
 289             // set the AudioInputStream length in frames if we know it
 290             if (stream instanceof AudioInputStream) {
 291                 frameLength = stream.getFrameLength();
 292             }
 293             // set framePos to zero
 294             framePos = 0;
 295             frameSize = inputFormat.getFrameSize();
 296             if (frameSize == AudioSystem.NOT_SPECIFIED) {
 297                 frameSize = 1;
 298             }
 299         }
 300 

 301         /*
 302          * $$jb 2/23/99
 303          * Used to determine segment number in uLaw encoding
 304          */
 305         private short search(short val, short table[], short size) {
 306             for(short i = 0; i < size; i++) {
 307                 if (val <= table[i]) { return i; }
 308             }
 309             return size;
 310         }
 311 
 312         /**
 313          * Note that this won't actually read anything; must read in
 314          * two-byte units.
 315          */
 316         @Override
 317         public int read() throws IOException {
 318             byte[] b = new byte[1];
 319             if (read(b, 0, b.length) == 1) {
 320                 return b[1] & 0xFF;
 321             }
 322             return -1;
 323         }
 324 
 325         @Override
 326         public int read(byte[] b) throws IOException {
 327             return read(b, 0, b.length);
 328         }
 329 
 330         @Override
 331         public int read(byte[] b, int off, int len) throws IOException {
 332             // don't read fractional frames
 333             if( len%frameSize != 0 ) {
 334                 len -= (len%frameSize);
 335             }
 336             if (encode) {
 337                 short BIAS = 0x84;
 338                 short mask;
 339                 short seg;
 340                 int i;
 341 
 342                 short sample;
 343                 byte enc;
 344 
 345                 int readCount = 0;
 346                 int currentPos = off;
 347                 int readLeft = len*2;
 348                 int readLen = ( (readLeft>tempBufferSize) ? tempBufferSize : readLeft );
 349 
 350                 while ((readCount = super.read(tempBuffer,0,readLen))>0) {


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