How to use

CodeWordCoder

in

it.unimi.dsi.compression

@Override
public BitVector[] codeWords() {
  return coder.codeWords();
}

coder = new CodeWordCoder(decoder.buildCodes());
  final BitVector[] codeWord = coder.codeWords();
  System.err.println("Codes: ");
  for(int i = 0; i < size; i++)

/**
 * This verifies that a code book constructed from a given set of
 * frequencies may be reconstructed from the cord word bit lengths, given in
 * a non-decreasing order, together with the symbols in a correlated array.
 * 
 * @param frequency
 */
public void doRoundTripTest(final int[] frequency) {
  
  final DecoderInputs decoderInputs = new DecoderInputs();
  
  final HuffmanCodec codec = new HuffmanCodec(frequency, decoderInputs);
  if (log.isDebugEnabled()) {
    log.debug(printCodeBook(codec.codeWords()) + "\nlength[]="
        + Arrays.toString(decoderInputs.getLengths()) + "\nsymbol[]="
        + Arrays.toString(decoderInputs.getSymbols()));
  }
  
  final CanonicalFast64CodeWordDecoder actualDecoder = new CanonicalFast64CodeWordDecoder(
      decoderInputs.getLengths(), decoderInputs.getSymbols());
  for (int i = 0; i < frequency.length; i++) {
    final BooleanIterator coded = codec.coder().encode(i/*symbol*/);
    
    assertEquals(i, actualDecoder.decode(coded));
    
  }
}

coder = new CodeWordCoder( decoder.buildCodes() );
  final BitVector[] codeWord = coder.codeWords();
  System.err.println( "Codes: " );
  for( int i = 0; i < size; i++ ) 

/**
 * This verifies that a code book constructed from a given set of
 * frequencies may be reconstructed from the cord word bit lengths, given in
 * a non-decreasing order, together with the symbols in a correlated array.
 * 
 * @param frequency
 */
public void doRoundTripTest(final int[] frequency) {
  
  final DecoderInputs decoderInputs = new DecoderInputs();
  
  final HuffmanCodec codec = new HuffmanCodec(frequency, decoderInputs);
  if (log.isDebugEnabled()) {
    log.debug(printCodeBook(codec.codeWords()) + "\nlength[]="
        + Arrays.toString(decoderInputs.getLengths()) + "\nsymbol[]="
        + Arrays.toString(decoderInputs.getSymbols()));
  }
  
  final CanonicalFast64CodeWordDecoder actualDecoder = new CanonicalFast64CodeWordDecoder(
      decoderInputs.getLengths(), decoderInputs.getSymbols());
  for (int i = 0; i < frequency.length; i++) {
    final BooleanIterator coded = codec.coder().encode(i/*symbol*/);
    
    assertEquals(i, actualDecoder.decode(coded));
    
  }
}

coder = new CodeWordCoder( decoder.buildCodes() );
  final BitVector[] codeWord = coder.codeWords();
  System.err.println( "Codes: " );
  for( int i = 0; i < size; i++ ) 

public BitVector[] codeWords() {
  return coder.codeWords();
}

public BitVector[] codeWords() {
  return coder.codeWords();
}

return new Object[] { new HuTuckerCodec( packedFrequency ).coder().codeWords(), char2symbol };

return new Object[] { new HuTuckerCodec( packedFrequency ).coder().codeWords(), char2symbol };

private static Object[] getCoder(final Iterable<? extends CharSequence> iterable, boolean prefixFree) {
  // First of all, we gather frequencies for all Unicode characters
  long[] frequency = new long[Character.MAX_VALUE + 1];
  int maxWordLength = 0;
  CharSequence s;
  int n = 0;
  for(Iterator<? extends CharSequence> i = iterable.iterator(); i.hasNext();) {
    s = i.next();
    maxWordLength = Math.max(s.length(), maxWordLength);
    for(int j = s.length(); j-- != 0;) frequency[s.charAt(j)]++;
    n++;
  }
  // Then, we compute the number of actually used characters. We count from the start the stop character.
  int count = prefixFree ? 1 : 0;
  for(int i = frequency.length; i-- != 0;) if (frequency[i] != 0) count++;
  /* Now we remap used characters in f, building at the same time the map from characters to symbols (except for the stop character). */
  long[] packedFrequency = new long[count];
  final Char2IntMap char2symbol = new Char2IntOpenHashMap(count);
  for(int i = frequency.length, k = count; i-- != 0;) {
    if (frequency[i] != 0) {
      packedFrequency[--k] = frequency[i];
      char2symbol.put((char)i, k);
    }
  }
  if (prefixFree) packedFrequency[0] = n; // The stop character appears once in each string.
  // We now build the coder used to code the strings
  return new Object[] { new HuTuckerCodec(packedFrequency).coder().codeWords(), char2symbol };
}