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