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    1   /*
    2    * Copyright (c) 1999, 2011, Oracle and/or its affiliates. All rights reserved.
    3    * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
    4    *
    5    * This code is free software; you can redistribute it and/or modify it
    6    * under the terms of the GNU General Public License version 2 only, as
    7    * published by the Free Software Foundation.  Oracle designates this
    8    * particular file as subject to the "Classpath" exception as provided
    9    * by Oracle in the LICENSE file that accompanied this code.
   10    *
   11    * This code is distributed in the hope that it will be useful, but WITHOUT
   12    * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
   13    * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
   14    * version 2 for more details (a copy is included in the LICENSE file that
   15    * accompanied this code).
   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.InputStream;
   29   import java.io.IOException;
   30   
   31   import java.util.Vector;
   32   
   33   import javax.sound.sampled.AudioFormat;
   34   import javax.sound.sampled.AudioSystem;
   35   import javax.sound.sampled.AudioInputStream;
   36   
   37   
   38   /**
   39    * A-law encodes linear data, and decodes a-law data to linear data.
   40    *
   41    * @author Kara Kytle
   42    */
   43   public class AlawCodec extends SunCodec {
   44   
   45       /* Tables used for A-law decoding */
   46   
   47       final static byte ALAW_TABH[] = new byte[256];
   48       final static byte ALAW_TABL[] = new byte[256];
   49   
   50       private static final AudioFormat.Encoding[] alawEncodings = { AudioFormat.Encoding.ALAW, 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 input    = i ^ 0x55;
   61               int mantissa = (input & 0xf ) << 4;
   62               int segment  = (input & 0x70) >> 4;
   63               int value    = mantissa+8;
   64   
   65               if(segment>=1)
   66                   value+=0x100;
   67               if(segment>1)
   68                   value <<= (segment -1);
   69   
   70               if( (input & 0x80)==0 )
   71                   value = -value;
   72   
   73               ALAW_TABL[i] = (byte)value;
   74               ALAW_TABH[i] = (byte)(value>>8);
   75           }
   76       }
   77   
   78   
   79       /**
   80        * Constructs a new ALAW codec object.
   81        */
   82       public AlawCodec() {
   83   
   84           super(alawEncodings, alawEncodings);
   85       }
   86   
   87       // NEW CODE
   88   
   89       /**
   90        */
   91       public AudioFormat.Encoding[] getTargetEncodings(AudioFormat sourceFormat){
   92   
   93           if( sourceFormat.getEncoding().equals( AudioFormat.Encoding.PCM_SIGNED )) {
   94   
   95               if( sourceFormat.getSampleSizeInBits() == 16 ) {
   96   
   97                   AudioFormat.Encoding enc[] = new AudioFormat.Encoding[1];
   98                   enc[0] = AudioFormat.Encoding.ALAW;
   99                   return enc;
  100   
  101               } else {
  102                   return new AudioFormat.Encoding[0];
  103               }
  104           } else if( sourceFormat.getEncoding().equals( AudioFormat.Encoding.ALAW ) ) {
  105   
  106               if( sourceFormat.getSampleSizeInBits() == 8 ) {
  107   
  108                   AudioFormat.Encoding enc[] = new AudioFormat.Encoding[1];
  109                   enc[0] = AudioFormat.Encoding.PCM_SIGNED;
  110                   return enc;
  111   
  112               } else {
  113                   return new AudioFormat.Encoding[0];
  114               }
  115   
  116           } else {
  117               return new AudioFormat.Encoding[0];
  118           }
  119       }
  120   
  121       /**
  122        */
  123       public AudioFormat[] getTargetFormats(AudioFormat.Encoding targetEncoding, AudioFormat sourceFormat){
  124           if( (targetEncoding.equals( AudioFormat.Encoding.PCM_SIGNED ) && sourceFormat.getEncoding().equals( AudioFormat.Encoding.ALAW)) ||
  125               (targetEncoding.equals( AudioFormat.Encoding.ALAW) && sourceFormat.getEncoding().equals( AudioFormat.Encoding.PCM_SIGNED)) ) {
  126                   return getOutputFormats( sourceFormat );
  127               } else {
  128                   return new AudioFormat[0];
  129               }
  130       }
  131   
  132       /**
  133        */
  134       public AudioInputStream getAudioInputStream(AudioFormat.Encoding targetEncoding, AudioInputStream sourceStream){
  135           AudioFormat sourceFormat = sourceStream.getFormat();
  136           AudioFormat.Encoding sourceEncoding = sourceFormat.getEncoding();
  137   
  138           if( sourceEncoding.equals( targetEncoding ) ) {
  139               return sourceStream;
  140           } else {
  141               AudioFormat targetFormat = null;
  142               if( !isConversionSupported(targetEncoding,sourceStream.getFormat()) ) {
  143                   throw new IllegalArgumentException("Unsupported conversion: " + sourceStream.getFormat().toString() + " to " + targetEncoding.toString());
  144               }
  145               if( sourceEncoding.equals( AudioFormat.Encoding.ALAW ) &&
  146                   targetEncoding.equals( AudioFormat.Encoding.PCM_SIGNED ) ) {
  147   
  148                   targetFormat = new AudioFormat( targetEncoding,
  149                                                   sourceFormat.getSampleRate(),
  150                                                   16,
  151                                                   sourceFormat.getChannels(),
  152                                                   2*sourceFormat.getChannels(),
  153                                                   sourceFormat.getSampleRate(),
  154                                                   sourceFormat.isBigEndian());
  155   
  156               } else if( sourceEncoding.equals( AudioFormat.Encoding.PCM_SIGNED ) &&
  157                          targetEncoding.equals( AudioFormat.Encoding.ALAW ) ) {
  158   
  159                   targetFormat = new AudioFormat( targetEncoding,
  160                                                   sourceFormat.getSampleRate(),
  161                                                   8,
  162                                                   sourceFormat.getChannels(),
  163                                                   sourceFormat.getChannels(),
  164                                                   sourceFormat.getSampleRate(),
  165                                                   false);
  166               } else {
  167                   throw new IllegalArgumentException("Unsupported conversion: " + sourceStream.getFormat().toString() + " to " + targetEncoding.toString());
  168               }
  169               return getAudioInputStream( targetFormat, sourceStream );
  170           }
  171       }
  172   
  173       /**
  174        * use old code...
  175        */
  176       public AudioInputStream getAudioInputStream(AudioFormat targetFormat, AudioInputStream sourceStream){
  177           return getConvertedStream( targetFormat, sourceStream );
  178       }
  179   
  180   
  181       // OLD CODE
  182   
  183   
  184       /**
  185        * Opens the codec with the specified parameters.
  186        * @param stream stream from which data to be processed should be read
  187        * @param outputFormat desired data format of the stream after processing
  188        * @return stream from which processed data may be read
  189        * @throws IllegalArgumentException if the format combination supplied is
  190        * not supported.
  191        */
  192       /*  public AudioInputStream getConvertedStream(AudioFormat outputFormat, AudioInputStream stream) { */
  193       private AudioInputStream getConvertedStream(AudioFormat outputFormat, AudioInputStream stream) {
  194   
  195           AudioInputStream cs = null;
  196           AudioFormat inputFormat = stream.getFormat();
  197   
  198           if( inputFormat.matches(outputFormat) ) {
  199               cs = stream;
  200           } else {
  201               cs = (AudioInputStream) (new AlawCodecStream(stream, outputFormat));
  202           }
  203   
  204           return cs;
  205       }
  206   
  207       /**
  208        * Obtains the set of output formats supported by the codec
  209        * given a particular input format.
  210        * If no output formats are supported for this input format,
  211        * returns an array of length 0.
  212        * @return array of supported output formats.
  213        */
  214       /*  public AudioFormat[] getOutputFormats(AudioFormat inputFormat) { */
  215       private AudioFormat[] getOutputFormats(AudioFormat inputFormat) {
  216   
  217   
  218           Vector formats = new Vector();
  219           AudioFormat format;
  220   
  221           if ( AudioFormat.Encoding.PCM_SIGNED.equals(inputFormat.getEncoding())) {
  222               format = new AudioFormat(AudioFormat.Encoding.ALAW,
  223                                        inputFormat.getSampleRate(),
  224                                        8,
  225                                        inputFormat.getChannels(),
  226                                        inputFormat.getChannels(),
  227                                        inputFormat.getSampleRate(),
  228                                        false );
  229               formats.addElement(format);
  230           }
  231   
  232           if (AudioFormat.Encoding.ALAW.equals(inputFormat.getEncoding())) {
  233               format = new AudioFormat(AudioFormat.Encoding.PCM_SIGNED,
  234                                        inputFormat.getSampleRate(),
  235                                        16,
  236                                        inputFormat.getChannels(),
  237                                        inputFormat.getChannels()*2,
  238                                        inputFormat.getSampleRate(),
  239                                        false );
  240               formats.addElement(format);
  241               format = new AudioFormat(AudioFormat.Encoding.PCM_SIGNED,
  242                                        inputFormat.getSampleRate(),
  243                                        16,
  244                                        inputFormat.getChannels(),
  245                                        inputFormat.getChannels()*2,
  246                                        inputFormat.getSampleRate(),
  247                                        true );
  248               formats.addElement(format);
  249           }
  250   
  251           AudioFormat[] formatArray = new AudioFormat[formats.size()];
  252           for (int i = 0; i < formatArray.length; i++) {
  253               formatArray[i] = (AudioFormat)(formats.elementAt(i));
  254           }
  255           return formatArray;
  256       }
  257   
  258   
  259       class AlawCodecStream extends AudioInputStream {
  260   
  261           // tempBuffer required only for encoding (when encode is true)
  262           private static final int tempBufferSize = 64;
  263           private byte tempBuffer [] = null;
  264   
  265           /**
  266            * True to encode to a-law, false to decode to linear
  267            */
  268           boolean encode = false;
  269   
  270           AudioFormat encodeFormat;
  271           AudioFormat decodeFormat;
  272   
  273           byte tabByte1[] = null;
  274           byte tabByte2[] = null;
  275           int highByte = 0;
  276           int lowByte  = 1;
  277   
  278           AlawCodecStream(AudioInputStream stream, AudioFormat outputFormat) {
  279   
  280               super(stream, outputFormat, -1);
  281   
  282               AudioFormat inputFormat = stream.getFormat();
  283   
  284               // throw an IllegalArgumentException if not ok
  285               if ( ! (isConversionSupported(outputFormat, inputFormat)) ) {
  286   
  287                   throw new IllegalArgumentException("Unsupported conversion: " + inputFormat.toString() + " to " + outputFormat.toString());
  288               }
  289   
  290               //$$fb 2002-07-18: fix for 4714846: JavaSound ULAW (8-bit) encoder erroneously depends on endian-ness
  291               boolean PCMIsBigEndian;
  292   
  293               // determine whether we are encoding or decoding
  294               if (AudioFormat.Encoding.ALAW.equals(inputFormat.getEncoding())) {
  295                   encode = false;
  296                   encodeFormat = inputFormat;
  297                   decodeFormat = outputFormat;
  298                   PCMIsBigEndian = outputFormat.isBigEndian();
  299               } else {
  300                   encode = true;
  301                   encodeFormat = outputFormat;
  302                   decodeFormat = inputFormat;
  303                   PCMIsBigEndian = inputFormat.isBigEndian();
  304                   tempBuffer = new byte[tempBufferSize];
  305               }
  306   
  307               if (PCMIsBigEndian) {
  308                   tabByte1 = ALAW_TABH;
  309                   tabByte2 = ALAW_TABL;
  310                   highByte = 0;
  311                   lowByte  = 1;
  312               } else {
  313                   tabByte1 = ALAW_TABL;
  314                   tabByte2 = ALAW_TABH;
  315                   highByte = 1;
  316                   lowByte  = 0;
  317               }
  318   
  319               // set the AudioInputStream length in frames if we know it
  320               if (stream instanceof AudioInputStream) {
  321                   frameLength = ((AudioInputStream)stream).getFrameLength();
  322               }
  323   
  324               // set framePos to zero
  325               framePos = 0;
  326               frameSize = inputFormat.getFrameSize();
  327               if( frameSize==AudioSystem.NOT_SPECIFIED ) {
  328                   frameSize=1;
  329               }
  330           }
  331   
  332   
  333           /*
  334            * $$jb 2/23/99
  335            * Used to determine segment number in aLaw encoding
  336            */
  337           private short search(short val, short table[], short size) {
  338               for(short i = 0; i < size; i++) {
  339                   if (val <= table[i]) { return i; }
  340               }
  341               return size;
  342           }
  343   
  344           /**
  345            * Note that this won't actually read anything; must read in
  346            * two-byte units.
  347            */
  348           public int read() throws IOException {
  349   
  350               byte[] b = new byte[1];
  351               return (int)read(b, 0, b.length);
  352           }
  353   
  354   
  355           public int read(byte[] b) throws IOException {
  356   
  357               return read(b, 0, b.length);
  358           }
  359   
  360           public int read(byte[] b, int off, int len) throws IOException {
  361   
  362               // don't read fractional frames
  363               if( len%frameSize != 0 ) {
  364                   len -= (len%frameSize);
  365               }
  366   
  367               if (encode) {
  368   
  369                   short QUANT_MASK = 0xF;
  370                   short SEG_SHIFT = 4;
  371                   short mask;
  372                   short seg;
  373                   int adj;
  374                   int i;
  375   
  376                   short sample;
  377                   byte enc;
  378   
  379                   int readCount = 0;
  380                   int currentPos = off;
  381                   int readLeft = len*2;
  382                   int readLen = ( (readLeft>tempBufferSize) ? tempBufferSize : readLeft );
  383   
  384                   while ((readCount = super.read(tempBuffer,0,readLen))>0) {
  385   
  386                       for (i = 0; i < readCount; i+=2) {
  387   
  388                           /* Get the sample from the tempBuffer */
  389                           sample = (short)(( (tempBuffer[i + highByte]) << 8) & 0xFF00);
  390                           sample |= (short)( (tempBuffer[i + lowByte]) & 0xFF);
  391   
  392                           if(sample >= 0) {
  393                               mask = 0xD5;
  394                           } else {
  395                               mask = 0x55;
  396                               sample = (short)(-sample - 8);
  397                           }
  398                           /* Convert the scaled magnitude to segment number. */
  399                           seg = search(sample, seg_end, (short) 8);
  400                           /*
  401                            * Combine the sign, segment, quantization bits
  402                            */
  403                           if (seg >= 8) {  /* out of range, return maximum value. */
  404                               enc = (byte) (0x7F ^ mask);
  405                           } else {
  406                               enc = (byte) (seg << SEG_SHIFT);
  407                               if(seg < 2) {
  408                                   enc |= (byte) ( (sample >> 4) & QUANT_MASK);
  409                               } else {
  410                                   enc |= (byte) ( (sample >> (seg + 3)) & QUANT_MASK );
  411                               }
  412                               enc ^= mask;
  413                           }
  414                           /* Now put the encoded sample where it belongs */
  415                           b[currentPos] = enc;
  416                           currentPos++;
  417                       }
  418                       /* And update pointers and counters for next iteration */
  419                       readLeft -= readCount;
  420                       readLen = ( (readLeft>tempBufferSize) ? tempBufferSize : readLeft );
  421                   }
  422   
  423                   if( currentPos==off && readCount<0 ) {  // EOF or error
  424                       return readCount;
  425                   }
  426   
  427                   return (currentPos - off);  /* Number of bytes written to new buffer */
  428   
  429               } else {
  430   
  431                   int i;
  432                   int readLen = len/2;
  433                   int readOffset = off + len/2;
  434                   int readCount = super.read(b, readOffset, readLen);
  435   
  436                   for (i = off; i < (off + (readCount*2)); i+=2) {
  437                       b[i]        = (byte)tabByte1[b[readOffset] & 0xFF];
  438                       b[i+1]      = (byte)tabByte2[b[readOffset] & 0xFF];
  439                       readOffset++;
  440                   }
  441   
  442                   if( readCount<0 ) {             // EOF or error
  443                       return readCount;
  444                   }
  445   
  446                   return (i - off);
  447               }
  448           }
  449       } // end class AlawCodecStream
  450   } // end class ALAW

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