release/src-rt/linux/linux-2.6/scripts/squashfs/lzma/CS/7zip/Compress/LZMA/LzmaBase.cs

   1 // LzmaBase.cs
   2
   3 namespace SevenZip.Compression.LZMA
   4 {
   5         internal abstract class Base
   6         {
   7                 public const uint kNumRepDistances = 4;
   8                 public const uint kNumStates = 12;
   9
  10                 // static byte []kLiteralNextStates  = {0, 0, 0, 0, 1, 2, 3, 4,  5,  6,   4, 5};
  11                 // static byte []kMatchNextStates    = {7, 7, 7, 7, 7, 7, 7, 10, 10, 10, 10, 10};
  12                 // static byte []kRepNextStates      = {8, 8, 8, 8, 8, 8, 8, 11, 11, 11, 11, 11};
  13                 // static byte []kShortRepNextStates = {9, 9, 9, 9, 9, 9, 9, 11, 11, 11, 11, 11};
  14
  15                 public struct State
  16                 {
  17                         public uint Index;
  18                         public void Init() { Index = 0; }
  19                         public void UpdateChar()
  20                         {
  21                                 if (Index < 4) Index = 0;
  22                                 else if (Index < 10) Index -= 3;
  23                                 else Index -= 6;
  24                         }
  25                         public void UpdateMatch() { Index = (uint)(Index < 7 ? 7 : 10); }
  26                         public void UpdateRep() { Index = (uint)(Index < 7 ? 8 : 11); }
  27                         public void UpdateShortRep() { Index = (uint)(Index < 7 ? 9 : 11); }
  28                   public bool IsCharState() { return Index < 7; }
  29                 }
  30
  31                 public const int kNumPosSlotBits = 6;
  32                 public const int kDicLogSizeMin = 0;
  33                 public const int kDicLogSizeMax = 28;
  34                 public const uint kDistTableSizeMax = kDicLogSizeMax * 2;
  35
  36                 public const int kNumLenToPosStatesBits = 2; // it's for speed optimization
  37                 public const uint kNumLenToPosStates = 1 << kNumLenToPosStatesBits;
  38
  39                 public const uint kMatchMinLen = 2;
  40
  41                 public static uint GetLenToPosState(uint len)
  42                 {
  43                         len -= kMatchMinLen;
  44                         if (len < kNumLenToPosStates)
  45                                 return len;
  46                         return (uint)(kNumLenToPosStates - 1);
  47                 }
  48
  49                 public const int kNumAlignBits = 4;
  50                 public const uint kAlignTableSize = 1 << kNumAlignBits;
  51                 public const uint kAlignMask = (kAlignTableSize - 1);
  52
  53                 public const uint kStartPosModelIndex = 4;
  54                 public const uint kEndPosModelIndex = 14;
  55                 public const uint kNumPosModels = kEndPosModelIndex - kStartPosModelIndex;
  56
  57                 public const uint kNumFullDistances = 1 << ((int)kEndPosModelIndex / 2);
  58
  59                 public const uint kNumLitPosStatesBitsEncodingMax = 4;
  60                 public const uint kNumLitContextBitsMax = 8;
  61
  62                 public const int kNumPosStatesBitsMax = 4;
  63                 public const uint kNumPosStatesMax = (1 << kNumPosStatesBitsMax);
  64                 public const int kNumPosStatesBitsEncodingMax = 4;
  65                 public const uint kNumPosStatesEncodingMax = (1 << kNumPosStatesBitsEncodingMax);
  66
  67                 public const int kNumLowLenBits = 3;
  68                 public const int kNumMidLenBits = 3;
  69                 public const int kNumHighLenBits = 8;
  70                 public const uint kNumLowLenSymbols = 1 << kNumLowLenBits;
  71                 public const uint kNumMidLenSymbols = 1 << kNumMidLenBits;
  72                 public const uint kNumLenSymbols = kNumLowLenSymbols + kNumMidLenSymbols +
  73                                 (1 << kNumHighLenBits);
  74                 public const uint kMatchMaxLen = kMatchMinLen + kNumLenSymbols - 1;
  75         }
  76 }