vcs.maemo.org Git - physicsfs/blob - lzma/Java/SevenZip/Compression/RangeCoder/Encoder.java

   1 package SevenZip.Compression.RangeCoder;
   2 import java.io.IOException;
   3
   4 public class Encoder
   5 {
   6         static final int kTopMask = ~((1 << 24) - 1);
   7
   8         static final int kNumBitModelTotalBits = 11;
   9         static final int kBitModelTotal = (1 << kNumBitModelTotalBits);
  10         static final int kNumMoveBits = 5;
  11
  12         java.io.OutputStream Stream;
  13
  14         long Low;
  15         int Range;
  16         int _cacheSize;
  17         int _cache;
  18
  19         long _position;
  20
  21         public void SetStream(java.io.OutputStream stream)
  22         {
  23                 Stream = stream;
  24         }
  25
  26         public void ReleaseStream()
  27         {
  28                 Stream = null;
  29         }
  30
  31         public void Init()
  32         {
  33                 _position = 0;
  34                 Low = 0;
  35                 Range = -1;
  36                 _cacheSize = 1;
  37                 _cache = 0;
  38         }
  39
  40         public void FlushData() throws IOException
  41         {
  42                 for (int i = 0; i < 5; i++)
  43                         ShiftLow();
  44         }
  45
  46         public void FlushStream() throws IOException
  47         {
  48                 Stream.flush();
  49         }
  50
  51         public void ShiftLow() throws IOException
  52         {
  53                 int LowHi = (int)(Low >>> 32);
  54                 if (LowHi != 0 || Low < 0xFF000000L)
  55                 {
  56                         _position += _cacheSize;
  57                         int temp = _cache;
  58                         do
  59                         {
  60                                 Stream.write(temp + LowHi);
  61                                 temp = 0xFF;
  62                         }
  63                         while(--_cacheSize != 0);
  64                         _cache = (((int)Low) >>> 24);
  65                 }
  66                 _cacheSize++;
  67                 Low = (Low & 0xFFFFFF) << 8;
  68         }
  69
  70         public void EncodeDirectBits(int v, int numTotalBits) throws IOException
  71         {
  72                 for (int i = numTotalBits - 1; i >= 0; i--)
  73                 {
  74                         Range >>>= 1;
  75                         if (((v >>> i) & 1) == 1)
  76                                 Low += Range;
  77                         if ((Range & Encoder.kTopMask) == 0)
  78                         {
  79                                 Range <<= 8;
  80                                 ShiftLow();
  81                         }
  82                 }
  83         }
  84
  85
  86         public long GetProcessedSizeAdd()
  87         {
  88                 return _cacheSize + _position + 4;
  89         }
  90
  91
  92
  93         static final int kNumMoveReducingBits = 2;
  94         public static final int kNumBitPriceShiftBits = 6;
  95
  96         public static void InitBitModels(short []probs)
  97         {
  98                 for (int i = 0; i < probs.length; i++)
  99                         probs[i] = (kBitModelTotal >>> 1);
 100         }
 101
 102         public void Encode(short []probs, int index, int symbol) throws IOException
 103         {
 104                 int prob = probs[index];
 105                 int newBound = (Range >>> kNumBitModelTotalBits) * prob;
 106                 if (symbol == 0)
 107                 {
 108                         Range = newBound;
 109                         probs[index] = (short)(prob + ((kBitModelTotal - prob) >>> kNumMoveBits));
 110                 }
 111                 else
 112                 {
 113                         Low += (newBound & 0xFFFFFFFFL);
 114                         Range -= newBound;
 115                         probs[index] = (short)(prob - ((prob) >>> kNumMoveBits));
 116                 }
 117                 if ((Range & kTopMask) == 0)
 118                 {
 119                         Range <<= 8;
 120                         ShiftLow();
 121                 }
 122         }
 123
 124         private static int[] ProbPrices = new int[kBitModelTotal >>> kNumMoveReducingBits];
 125
 126         static
 127         {
 128                 int kNumBits = (kNumBitModelTotalBits - kNumMoveReducingBits);
 129                 for (int i = kNumBits - 1; i >= 0; i--)
 130                 {
 131                         int start = 1 << (kNumBits - i - 1);
 132                         int end = 1 << (kNumBits - i);
 133                         for (int j = start; j < end; j++)
 134                                 ProbPrices[j] = (i << kNumBitPriceShiftBits) +
 135                                                 (((end - j) << kNumBitPriceShiftBits) >>> (kNumBits - i - 1));
 136                 }
 137         }
 138
 139         static public int GetPrice(int Prob, int symbol)
 140         {
 141                 return ProbPrices[(((Prob - symbol) ^ ((-symbol))) & (kBitModelTotal - 1)) >>> kNumMoveReducingBits];
 142         }
 143         static public int GetPrice0(int Prob)
 144         {
 145                 return ProbPrices[Prob >>> kNumMoveReducingBits];
 146         }
 147         static public int GetPrice1(int Prob)
 148         {
 149                 return ProbPrices[(kBitModelTotal - Prob) >>> kNumMoveReducingBits];
 150         }
 151 }