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 | }
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