release/src-rt-6.x/linux/linux-2.6/scripts/squashfs/lzma/Java/SevenZip/Compression/RangeCoder/BitTreeDecoder.java

   1 package SevenZip.Compression.RangeCoder;
   2
   3 public class BitTreeDecoder
   4 {
   5         short[] Models;
   6         int NumBitLevels;
   7
   8         public BitTreeDecoder(int numBitLevels)
   9         {
  10                 NumBitLevels = numBitLevels;
  11                 Models = new short[1 << numBitLevels];
  12         }
  13
  14         public void Init()
  15         {
  16                 Decoder.InitBitModels(Models);
  17         }
  18
  19         public int Decode(Decoder rangeDecoder) throws java.io.IOException
  20         {
  21                 int m = 1;
  22                 for (int bitIndex = NumBitLevels; bitIndex != 0; bitIndex--)
  23                         m = (m << 1) + rangeDecoder.DecodeBit(Models, m);
  24                 return m - (1 << NumBitLevels);
  25         }
  26
  27         public int ReverseDecode(Decoder rangeDecoder) throws java.io.IOException
  28         {
  29                 int m = 1;
  30                 int symbol = 0;
  31                 for (int bitIndex = 0; bitIndex < NumBitLevels; bitIndex++)
  32                 {
  33                         int bit = rangeDecoder.DecodeBit(Models, m);
  34                         m <<= 1;
  35                         m += bit;
  36                         symbol |= (bit << bitIndex);
  37                 }
  38                 return symbol;
  39         }
  40
  41         public static int ReverseDecode(short[] Models, int startIndex,
  42                         Decoder rangeDecoder, int NumBitLevels) throws java.io.IOException
  43         {
  44                 int m = 1;
  45                 int symbol = 0;
  46                 for (int bitIndex = 0; bitIndex < NumBitLevels; bitIndex++)
  47                 {
  48                         int bit = rangeDecoder.DecodeBit(Models, startIndex + m);
  49                         m <<= 1;
  50                         m += bit;
  51                         symbol |= (bit << bitIndex);
  52                 }
  53                 return symbol;
  54         }
  55 }