1 | /*
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2 | * LZMA2 decoder
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3 | *
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4 | * Authors: Lasse Collin <lasse.collin@tukaani.org>
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5 | * Igor Pavlov <http://7-zip.org/>
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6 | *
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7 | * This file has been put into the public domain.
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8 | * You can do whatever you want with this file.
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9 | */
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10 |
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11 | #include "xz_private.h"
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12 | #include "xz_lzma2.h"
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13 |
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14 | /*
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15 | * Range decoder initialization eats the first five bytes of each LZMA chunk.
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16 | */
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17 | #define RC_INIT_BYTES 5
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18 |
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19 | /*
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20 | * Minimum number of usable input buffer to safely decode one LZMA symbol.
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21 | * The worst case is that we decode 22 bits using probabilities and 26
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22 | * direct bits. This may decode at maximum of 20 bytes of input. However,
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23 | * lzma_main() does an extra normalization before returning, thus we
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24 | * need to put 21 here.
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25 | */
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26 | #define LZMA_IN_REQUIRED 21
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27 |
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28 | /*
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29 | * Dictionary (history buffer)
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30 | *
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31 | * These are always true:
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32 | * start <= pos <= full <= end
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33 | * pos <= limit <= end
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34 | *
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35 | * In multi-call mode, also these are true:
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36 | * end == size
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37 | * size <= size_max
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38 | * allocated <= size
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39 | *
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40 | * Most of these variables are size_t to support single-call mode,
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41 | * in which the dictionary variables address the actual output
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42 | * buffer directly.
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43 | */
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44 | struct dictionary {
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45 | /* Beginning of the history buffer */
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46 | uint8_t *buf;
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47 |
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48 | /* Old position in buf (before decoding more data) */
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49 | size_t start;
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50 |
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51 | /* Position in buf */
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52 | size_t pos;
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53 |
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54 | /*
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55 | * How full dictionary is. This is used to detect corrupt input that
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56 | * would read beyond the beginning of the uncompressed stream.
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57 | */
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58 | size_t full;
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59 |
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60 | /* Write limit; we don't write to buf[limit] or later bytes. */
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61 | size_t limit;
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62 |
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63 | /*
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64 | * End of the dictionary buffer. In multi-call mode, this is
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65 | * the same as the dictionary size. In single-call mode, this
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66 | * indicates the size of the output buffer.
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67 | */
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68 | size_t end;
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69 |
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70 | /*
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71 | * Size of the dictionary as specified in Block Header. This is used
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72 | * together with "full" to detect corrupt input that would make us
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73 | * read beyond the beginning of the uncompressed stream.
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74 | */
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75 | uint32_t size;
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76 |
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77 | /*
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78 | * Maximum allowed dictionary size in multi-call mode.
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79 | * This is ignored in single-call mode.
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80 | */
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81 | uint32_t size_max;
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82 |
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83 | /*
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84 | * Amount of memory currently allocated for the dictionary.
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85 | * This is used only with XZ_DYNALLOC. (With XZ_PREALLOC,
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86 | * size_max is always the same as the allocated size.)
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87 | */
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88 | uint32_t allocated;
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89 |
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90 | /* Operation mode */
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91 | enum xz_mode mode;
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92 | };
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93 |
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94 | /* Range decoder */
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95 | struct rc_dec {
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96 | uint32_t range;
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97 | uint32_t code;
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98 |
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99 | /*
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100 | * Number of initializing bytes remaining to be read
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101 | * by rc_read_init().
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102 | */
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103 | uint32_t init_bytes_left;
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104 |
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105 | /*
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106 | * Buffer from which we read our input. It can be either
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107 | * temp.buf or the caller-provided input buffer.
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108 | */
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109 | const uint8_t *in;
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110 | size_t in_pos;
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111 | size_t in_limit;
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112 | };
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113 |
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114 | /* Probabilities for a length decoder. */
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115 | struct lzma_len_dec {
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116 | /* Probability of match length being at least 10 */
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117 | uint16_t choice;
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118 |
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119 | /* Probability of match length being at least 18 */
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120 | uint16_t choice2;
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121 |
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122 | /* Probabilities for match lengths 2-9 */
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123 | uint16_t low[POS_STATES_MAX][LEN_LOW_SYMBOLS];
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124 |
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125 | /* Probabilities for match lengths 10-17 */
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126 | uint16_t mid[POS_STATES_MAX][LEN_MID_SYMBOLS];
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127 |
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128 | /* Probabilities for match lengths 18-273 */
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129 | uint16_t high[LEN_HIGH_SYMBOLS];
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130 | };
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131 |
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132 | struct lzma_dec {
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133 | /* Distances of latest four matches */
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134 | uint32_t rep0;
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135 | uint32_t rep1;
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136 | uint32_t rep2;
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137 | uint32_t rep3;
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138 |
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139 | /* Types of the most recently seen LZMA symbols */
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140 | enum lzma_state state;
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141 |
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142 | /*
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143 | * Length of a match. This is updated so that dict_repeat can
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144 | * be called again to finish repeating the whole match.
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145 | */
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146 | uint32_t len;
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147 |
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148 | /*
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149 | * LZMA properties or related bit masks (number of literal
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150 | * context bits, a mask dervied from the number of literal
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151 | * position bits, and a mask dervied from the number
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152 | * position bits)
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153 | */
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154 | uint32_t lc;
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155 | uint32_t literal_pos_mask; /* (1 << lp) - 1 */
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156 | uint32_t pos_mask; /* (1 << pb) - 1 */
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157 |
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158 | /* If 1, it's a match. Otherwise it's a single 8-bit literal. */
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159 | uint16_t is_match[STATES][POS_STATES_MAX];
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160 |
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161 | /* If 1, it's a repeated match. The distance is one of rep0 .. rep3. */
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162 | uint16_t is_rep[STATES];
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163 |
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164 | /*
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165 | * If 0, distance of a repeated match is rep0.
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166 | * Otherwise check is_rep1.
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167 | */
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168 | uint16_t is_rep0[STATES];
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169 |
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170 | /*
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171 | * If 0, distance of a repeated match is rep1.
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172 | * Otherwise check is_rep2.
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173 | */
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174 | uint16_t is_rep1[STATES];
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175 |
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176 | /* If 0, distance of a repeated match is rep2. Otherwise it is rep3. */
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177 | uint16_t is_rep2[STATES];
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178 |
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179 | /*
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180 | * If 1, the repeated match has length of one byte. Otherwise
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181 | * the length is decoded from rep_len_decoder.
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182 | */
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183 | uint16_t is_rep0_long[STATES][POS_STATES_MAX];
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184 |
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185 | /*
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186 | * Probability tree for the highest two bits of the match
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187 | * distance. There is a separate probability tree for match
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188 | * lengths of 2 (i.e. MATCH_LEN_MIN), 3, 4, and [5, 273].
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189 | */
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190 | uint16_t dist_slot[DIST_STATES][DIST_SLOTS];
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191 |
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192 | /*
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193 | * Probility trees for additional bits for match distance
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194 | * when the distance is in the range [4, 127].
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195 | */
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196 | uint16_t dist_special[FULL_DISTANCES - DIST_MODEL_END];
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197 |
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198 | /*
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199 | * Probability tree for the lowest four bits of a match
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200 | * distance that is equal to or greater than 128.
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201 | */
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202 | uint16_t dist_align[ALIGN_SIZE];
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203 |
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204 | /* Length of a normal match */
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205 | struct lzma_len_dec match_len_dec;
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206 |
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207 | /* Length of a repeated match */
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208 | struct lzma_len_dec rep_len_dec;
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209 |
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210 | /* Probabilities of literals */
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211 | uint16_t literal[LITERAL_CODERS_MAX][LITERAL_CODER_SIZE];
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212 | };
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213 |
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214 | struct lzma2_dec {
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215 | /* Position in xz_dec_lzma2_run(). */
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216 | enum lzma2_seq {
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217 | SEQ_CONTROL,
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218 | SEQ_UNCOMPRESSED_1,
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219 | SEQ_UNCOMPRESSED_2,
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220 | SEQ_COMPRESSED_0,
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221 | SEQ_COMPRESSED_1,
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222 | SEQ_PROPERTIES,
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223 | SEQ_LZMA_PREPARE,
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224 | SEQ_LZMA_RUN,
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225 | SEQ_COPY
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226 | } sequence;
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227 |
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228 | /* Next position after decoding the compressed size of the chunk. */
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229 | enum lzma2_seq next_sequence;
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230 |
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231 | /* Uncompressed size of LZMA chunk (2 MiB at maximum) */
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232 | uint32_t uncompressed;
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233 |
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234 | /*
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235 | * Compressed size of LZMA chunk or compressed/uncompressed
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236 | * size of uncompressed chunk (64 KiB at maximum)
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237 | */
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238 | uint32_t compressed;
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239 |
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240 | /*
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241 | * True if dictionary reset is needed. This is false before
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242 | * the first chunk (LZMA or uncompressed).
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243 | */
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244 | bool need_dict_reset;
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245 |
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246 | /*
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247 | * True if new LZMA properties are needed. This is false
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248 | * before the first LZMA chunk.
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249 | */
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250 | bool need_props;
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251 | };
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252 |
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253 | struct xz_dec_lzma2 {
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254 | /*
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255 | * The order below is important on x86 to reduce code size and
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256 | * it shouldn't hurt on other platforms. Everything up to and
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257 | * including lzma.pos_mask are in the first 128 bytes on x86-32,
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258 | * which allows using smaller instructions to access those
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259 | * variables. On x86-64, fewer variables fit into the first 128
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260 | * bytes, but this is still the best order without sacrificing
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261 | * the readability by splitting the structures.
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262 | */
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263 | struct rc_dec rc;
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264 | struct dictionary dict;
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265 | struct lzma2_dec lzma2;
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266 | struct lzma_dec lzma;
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267 |
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268 | /*
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269 | * Temporary buffer which holds small number of input bytes between
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270 | * decoder calls. See lzma2_lzma() for details.
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271 | */
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272 | struct {
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273 | uint32_t size;
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274 | uint8_t buf[3 * LZMA_IN_REQUIRED];
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275 | } temp;
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276 | };
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277 |
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278 | /**************
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279 | * Dictionary *
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280 | **************/
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281 |
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282 | /*
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283 | * Reset the dictionary state. When in single-call mode, set up the beginning
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284 | * of the dictionary to point to the actual output buffer.
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285 | */
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286 | static void XZ_FUNC dict_reset(struct dictionary *dict, struct xz_buf *b)
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287 | {
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288 | if (DEC_IS_SINGLE(dict->mode)) {
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289 | dict->buf = b->out + b->out_pos;
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290 | dict->end = b->out_size - b->out_pos;
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291 | }
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292 |
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293 | dict->start = 0;
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294 | dict->pos = 0;
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295 | dict->limit = 0;
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296 | dict->full = 0;
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297 | }
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298 |
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299 | /* Set dictionary write limit */
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300 | static void XZ_FUNC dict_limit(struct dictionary *dict, size_t out_max)
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301 | {
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302 | if (dict->end - dict->pos <= out_max)
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303 | dict->limit = dict->end;
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304 | else
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305 | dict->limit = dict->pos + out_max;
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306 | }
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307 |
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308 | /* Return true if at least one byte can be written into the dictionary. */
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309 | static __always_inline bool XZ_FUNC dict_has_space(const struct dictionary *dict)
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310 | {
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311 | return dict->pos < dict->limit;
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312 | }
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313 |
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314 | /*
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315 | * Get a byte from the dictionary at the given distance. The distance is
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316 | * assumed to valid, or as a special case, zero when the dictionary is
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317 | * still empty. This special case is needed for single-call decoding to
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318 | * avoid writing a '\0' to the end of the destination buffer.
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319 | */
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320 | static __always_inline uint32_t XZ_FUNC dict_get(
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321 | const struct dictionary *dict, uint32_t dist)
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322 | {
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323 | size_t offset = dict->pos - dist - 1;
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324 |
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325 | if (dist >= dict->pos)
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326 | offset += dict->end;
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327 |
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328 | return dict->full > 0 ? dict->buf[offset] : 0;
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329 | }
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330 |
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331 | /*
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332 | * Put one byte into the dictionary. It is assumed that there is space for it.
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333 | */
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334 | static inline void XZ_FUNC dict_put(struct dictionary *dict, uint8_t byte)
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335 | {
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336 | dict->buf[dict->pos++] = byte;
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337 |
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338 | if (dict->full < dict->pos)
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339 | dict->full = dict->pos;
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340 | }
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341 |
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342 | /*
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343 | * Repeat given number of bytes from the given distance. If the distance is
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344 | * invalid, false is returned. On success, true is returned and *len is
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345 | * updated to indicate how many bytes were left to be repeated.
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346 | */
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347 | static bool XZ_FUNC dict_repeat(
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348 | struct dictionary *dict, uint32_t *len, uint32_t dist)
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349 | {
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350 | size_t back;
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351 | uint32_t left;
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352 |
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353 | if (dist >= dict->full || dist >= dict->size)
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354 | return false;
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355 |
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356 | left = min_t(size_t, dict->limit - dict->pos, *len);
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357 | *len -= left;
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358 |
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359 | back = dict->pos - dist - 1;
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360 | if (dist >= dict->pos)
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361 | back += dict->end;
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362 |
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363 | do {
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364 | dict->buf[dict->pos++] = dict->buf[back++];
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365 | if (back == dict->end)
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366 | back = 0;
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367 | } while (--left > 0);
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368 |
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369 | if (dict->full < dict->pos)
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370 | dict->full = dict->pos;
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371 |
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372 | return true;
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373 | }
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374 |
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375 | /* Copy uncompressed data as is from input to dictionary and output buffers. */
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376 | static void XZ_FUNC dict_uncompressed(
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377 | struct dictionary *dict, struct xz_buf *b, uint32_t *left)
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378 | {
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379 | size_t copy_size;
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380 |
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381 | while (*left > 0 && b->in_pos < b->in_size
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382 | && b->out_pos < b->out_size) {
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383 | copy_size = min(b->in_size - b->in_pos,
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384 | b->out_size - b->out_pos);
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385 | if (copy_size > dict->end - dict->pos)
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386 | copy_size = dict->end - dict->pos;
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387 | if (copy_size > *left)
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388 | copy_size = *left;
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389 |
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390 | *left -= copy_size;
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391 |
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392 | memcpy(dict->buf + dict->pos, b->in + b->in_pos, copy_size);
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393 | dict->pos += copy_size;
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394 |
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395 | if (dict->full < dict->pos)
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396 | dict->full = dict->pos;
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397 |
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398 | if (DEC_IS_MULTI(dict->mode)) {
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399 | if (dict->pos == dict->end)
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400 | dict->pos = 0;
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401 |
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402 | memcpy(b->out + b->out_pos, b->in + b->in_pos,
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403 | copy_size);
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404 | }
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405 |
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406 | dict->start = dict->pos;
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407 |
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408 | b->out_pos += copy_size;
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409 | b->in_pos += copy_size;
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410 |
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411 | }
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412 | }
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413 |
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414 | /*
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415 | * Flush pending data from dictionary to b->out. It is assumed that there is
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416 | * enough space in b->out. This is guaranteed because caller uses dict_limit()
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417 | * before decoding data into the dictionary.
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418 | */
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419 | static uint32_t XZ_FUNC dict_flush(struct dictionary *dict, struct xz_buf *b)
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420 | {
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421 | size_t copy_size = dict->pos - dict->start;
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422 |
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423 | if (DEC_IS_MULTI(dict->mode)) {
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424 | if (dict->pos == dict->end)
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425 | dict->pos = 0;
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426 |
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427 | memcpy(b->out + b->out_pos, dict->buf + dict->start,
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428 | copy_size);
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429 | }
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430 |
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431 | dict->start = dict->pos;
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432 | b->out_pos += copy_size;
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433 | return copy_size;
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434 | }
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435 |
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436 | /*****************
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437 | * Range decoder *
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438 | *****************/
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439 |
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440 | /* Reset the range decoder. */
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441 | static void XZ_FUNC rc_reset(struct rc_dec *rc)
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442 | {
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443 | rc->range = (uint32_t)-1;
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444 | rc->code = 0;
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445 | rc->init_bytes_left = RC_INIT_BYTES;
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446 | }
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447 |
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448 | /*
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449 | * Read the first five initial bytes into rc->code if they haven't been
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450 | * read already. (Yes, the first byte gets completely ignored.)
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451 | */
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452 | static bool XZ_FUNC rc_read_init(struct rc_dec *rc, struct xz_buf *b)
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453 | {
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454 | while (rc->init_bytes_left > 0) {
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455 | if (b->in_pos == b->in_size)
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456 | return false;
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457 |
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458 | rc->code = (rc->code << 8) + b->in[b->in_pos++];
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459 | --rc->init_bytes_left;
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460 | }
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461 |
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462 | return true;
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463 | }
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464 |
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465 | /* Return true if there may not be enough input for the next decoding loop. */
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466 | static inline bool XZ_FUNC rc_limit_exceeded(const struct rc_dec *rc)
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467 | {
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468 | return rc->in_pos > rc->in_limit;
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469 | }
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470 |
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471 | /*
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472 | * Return true if it is possible (from point of view of range decoder) that
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473 | * we have reached the end of the LZMA chunk.
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474 | */
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475 | static inline bool XZ_FUNC rc_is_finished(const struct rc_dec *rc)
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476 | {
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477 | return rc->code == 0;
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478 | }
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479 |
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480 | /* Read the next input byte if needed. */
|
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481 | static __always_inline void XZ_FUNC rc_normalize(struct rc_dec *rc)
|
---|
482 | {
|
---|
483 | if (rc->range < RC_TOP_VALUE) {
|
---|
484 | rc->range <<= RC_SHIFT_BITS;
|
---|
485 | rc->code = (rc->code << RC_SHIFT_BITS) + rc->in[rc->in_pos++];
|
---|
486 | }
|
---|
487 | }
|
---|
488 |
|
---|
489 | /*
|
---|
490 | * Decode one bit. In some versions, this function has been splitted in three
|
---|
491 | * functions so that the compiler is supposed to be able to more easily avoid
|
---|
492 | * an extra branch. In this particular version of the LZMA decoder, this
|
---|
493 | * doesn't seem to be a good idea (tested with GCC 3.3.6, 3.4.6, and 4.3.3
|
---|
494 | * on x86). Using a non-splitted version results in nicer looking code too.
|
---|
495 | *
|
---|
496 | * NOTE: This must return an int. Do not make it return a bool or the speed
|
---|
497 | * of the code generated by GCC 3.x decreases 10-15 %. (GCC 4.3 doesn't care,
|
---|
498 | * and it generates 10-20 % faster code than GCC 3.x from this file anyway.)
|
---|
499 | */
|
---|
500 | static __always_inline int XZ_FUNC rc_bit(struct rc_dec *rc, uint16_t *prob)
|
---|
501 | {
|
---|
502 | uint32_t bound;
|
---|
503 | int bit;
|
---|
504 |
|
---|
505 | rc_normalize(rc);
|
---|
506 | bound = (rc->range >> RC_BIT_MODEL_TOTAL_BITS) * *prob;
|
---|
507 | if (rc->code < bound) {
|
---|
508 | rc->range = bound;
|
---|
509 | *prob += (RC_BIT_MODEL_TOTAL - *prob) >> RC_MOVE_BITS;
|
---|
510 | bit = 0;
|
---|
511 | } else {
|
---|
512 | rc->range -= bound;
|
---|
513 | rc->code -= bound;
|
---|
514 | *prob -= *prob >> RC_MOVE_BITS;
|
---|
515 | bit = 1;
|
---|
516 | }
|
---|
517 |
|
---|
518 | return bit;
|
---|
519 | }
|
---|
520 |
|
---|
521 | /* Decode a bittree starting from the most significant bit. */
|
---|
522 | static __always_inline uint32_t XZ_FUNC rc_bittree(
|
---|
523 | struct rc_dec *rc, uint16_t *probs, uint32_t limit)
|
---|
524 | {
|
---|
525 | uint32_t symbol = 1;
|
---|
526 |
|
---|
527 | do {
|
---|
528 | if (rc_bit(rc, &probs[symbol]))
|
---|
529 | symbol = (symbol << 1) + 1;
|
---|
530 | else
|
---|
531 | symbol <<= 1;
|
---|
532 | } while (symbol < limit);
|
---|
533 |
|
---|
534 | return symbol;
|
---|
535 | }
|
---|
536 |
|
---|
537 | /* Decode a bittree starting from the least significant bit. */
|
---|
538 | static __always_inline void XZ_FUNC rc_bittree_reverse(struct rc_dec *rc,
|
---|
539 | uint16_t *probs, uint32_t *dest, uint32_t limit)
|
---|
540 | {
|
---|
541 | uint32_t symbol = 1;
|
---|
542 | uint32_t i = 0;
|
---|
543 |
|
---|
544 | do {
|
---|
545 | if (rc_bit(rc, &probs[symbol])) {
|
---|
546 | symbol = (symbol << 1) + 1;
|
---|
547 | *dest += 1 << i;
|
---|
548 | } else {
|
---|
549 | symbol <<= 1;
|
---|
550 | }
|
---|
551 | } while (++i < limit);
|
---|
552 | }
|
---|
553 |
|
---|
554 | /* Decode direct bits (fixed fifty-fifty probability) */
|
---|
555 | static inline void XZ_FUNC rc_direct(
|
---|
556 | struct rc_dec *rc, uint32_t *dest, uint32_t limit)
|
---|
557 | {
|
---|
558 | uint32_t mask;
|
---|
559 |
|
---|
560 | do {
|
---|
561 | rc_normalize(rc);
|
---|
562 | rc->range >>= 1;
|
---|
563 | rc->code -= rc->range;
|
---|
564 | mask = (uint32_t)0 - (rc->code >> 31);
|
---|
565 | rc->code += rc->range & mask;
|
---|
566 | *dest = (*dest << 1) + (mask + 1);
|
---|
567 | } while (--limit > 0);
|
---|
568 | }
|
---|
569 |
|
---|
570 | /********
|
---|
571 | * LZMA *
|
---|
572 | ********/
|
---|
573 |
|
---|
574 | /* Get pointer to literal coder probability array. */
|
---|
575 | static uint16_t * XZ_FUNC lzma_literal_probs(struct xz_dec_lzma2 *s)
|
---|
576 | {
|
---|
577 | uint32_t prev_byte = dict_get(&s->dict, 0);
|
---|
578 | uint32_t low = prev_byte >> (8 - s->lzma.lc);
|
---|
579 | uint32_t high = (s->dict.pos & s->lzma.literal_pos_mask) << s->lzma.lc;
|
---|
580 | return s->lzma.literal[low + high];
|
---|
581 | }
|
---|
582 |
|
---|
583 | /* Decode a literal (one 8-bit byte) */
|
---|
584 | static void XZ_FUNC lzma_literal(struct xz_dec_lzma2 *s)
|
---|
585 | {
|
---|
586 | uint16_t *probs;
|
---|
587 | uint32_t symbol;
|
---|
588 | uint32_t match_byte;
|
---|
589 | uint32_t match_bit;
|
---|
590 | uint32_t offset;
|
---|
591 | uint32_t i;
|
---|
592 |
|
---|
593 | probs = lzma_literal_probs(s);
|
---|
594 |
|
---|
595 | if (lzma_state_is_literal(s->lzma.state)) {
|
---|
596 | symbol = rc_bittree(&s->rc, probs, 0x100);
|
---|
597 | } else {
|
---|
598 | symbol = 1;
|
---|
599 | match_byte = dict_get(&s->dict, s->lzma.rep0) << 1;
|
---|
600 | offset = 0x100;
|
---|
601 |
|
---|
602 | do {
|
---|
603 | match_bit = match_byte & offset;
|
---|
604 | match_byte <<= 1;
|
---|
605 | i = offset + match_bit + symbol;
|
---|
606 |
|
---|
607 | if (rc_bit(&s->rc, &probs[i])) {
|
---|
608 | symbol = (symbol << 1) + 1;
|
---|
609 | offset &= match_bit;
|
---|
610 | } else {
|
---|
611 | symbol <<= 1;
|
---|
612 | offset &= ~match_bit;
|
---|
613 | }
|
---|
614 | } while (symbol < 0x100);
|
---|
615 | }
|
---|
616 |
|
---|
617 | dict_put(&s->dict, (uint8_t)symbol);
|
---|
618 | lzma_state_literal(&s->lzma.state);
|
---|
619 | }
|
---|
620 |
|
---|
621 | /* Decode the length of the match into s->lzma.len. */
|
---|
622 | static void XZ_FUNC lzma_len(struct xz_dec_lzma2 *s, struct lzma_len_dec *l,
|
---|
623 | uint32_t pos_state)
|
---|
624 | {
|
---|
625 | uint16_t *probs;
|
---|
626 | uint32_t limit;
|
---|
627 |
|
---|
628 | if (!rc_bit(&s->rc, &l->choice)) {
|
---|
629 | probs = l->low[pos_state];
|
---|
630 | limit = LEN_LOW_SYMBOLS;
|
---|
631 | s->lzma.len = MATCH_LEN_MIN;
|
---|
632 | } else {
|
---|
633 | if (!rc_bit(&s->rc, &l->choice2)) {
|
---|
634 | probs = l->mid[pos_state];
|
---|
635 | limit = LEN_MID_SYMBOLS;
|
---|
636 | s->lzma.len = MATCH_LEN_MIN + LEN_LOW_SYMBOLS;
|
---|
637 | } else {
|
---|
638 | probs = l->high;
|
---|
639 | limit = LEN_HIGH_SYMBOLS;
|
---|
640 | s->lzma.len = MATCH_LEN_MIN + LEN_LOW_SYMBOLS
|
---|
641 | + LEN_MID_SYMBOLS;
|
---|
642 | }
|
---|
643 | }
|
---|
644 |
|
---|
645 | s->lzma.len += rc_bittree(&s->rc, probs, limit) - limit;
|
---|
646 | }
|
---|
647 |
|
---|
648 | /* Decode a match. The distance will be stored in s->lzma.rep0. */
|
---|
649 | static void XZ_FUNC lzma_match(struct xz_dec_lzma2 *s, uint32_t pos_state)
|
---|
650 | {
|
---|
651 | uint16_t *probs;
|
---|
652 | uint32_t dist_slot;
|
---|
653 | uint32_t limit;
|
---|
654 |
|
---|
655 | lzma_state_match(&s->lzma.state);
|
---|
656 |
|
---|
657 | s->lzma.rep3 = s->lzma.rep2;
|
---|
658 | s->lzma.rep2 = s->lzma.rep1;
|
---|
659 | s->lzma.rep1 = s->lzma.rep0;
|
---|
660 |
|
---|
661 | lzma_len(s, &s->lzma.match_len_dec, pos_state);
|
---|
662 |
|
---|
663 | probs = s->lzma.dist_slot[lzma_get_dist_state(s->lzma.len)];
|
---|
664 | dist_slot = rc_bittree(&s->rc, probs, DIST_SLOTS) - DIST_SLOTS;
|
---|
665 |
|
---|
666 | if (dist_slot < DIST_MODEL_START) {
|
---|
667 | s->lzma.rep0 = dist_slot;
|
---|
668 | } else {
|
---|
669 | limit = (dist_slot >> 1) - 1;
|
---|
670 | s->lzma.rep0 = 2 + (dist_slot & 1);
|
---|
671 |
|
---|
672 | if (dist_slot < DIST_MODEL_END) {
|
---|
673 | s->lzma.rep0 <<= limit;
|
---|
674 | probs = s->lzma.dist_special + s->lzma.rep0
|
---|
675 | - dist_slot - 1;
|
---|
676 | rc_bittree_reverse(&s->rc, probs,
|
---|
677 | &s->lzma.rep0, limit);
|
---|
678 | } else {
|
---|
679 | rc_direct(&s->rc, &s->lzma.rep0, limit - ALIGN_BITS);
|
---|
680 | s->lzma.rep0 <<= ALIGN_BITS;
|
---|
681 | rc_bittree_reverse(&s->rc, s->lzma.dist_align,
|
---|
682 | &s->lzma.rep0, ALIGN_BITS);
|
---|
683 | }
|
---|
684 | }
|
---|
685 | }
|
---|
686 |
|
---|
687 | /*
|
---|
688 | * Decode a repeated match. The distance is one of the four most recently
|
---|
689 | * seen matches. The distance will be stored in s->lzma.rep0.
|
---|
690 | */
|
---|
691 | static void XZ_FUNC lzma_rep_match(struct xz_dec_lzma2 *s, uint32_t pos_state)
|
---|
692 | {
|
---|
693 | uint32_t tmp;
|
---|
694 |
|
---|
695 | if (!rc_bit(&s->rc, &s->lzma.is_rep0[s->lzma.state])) {
|
---|
696 | if (!rc_bit(&s->rc, &s->lzma.is_rep0_long[
|
---|
697 | s->lzma.state][pos_state])) {
|
---|
698 | lzma_state_short_rep(&s->lzma.state);
|
---|
699 | s->lzma.len = 1;
|
---|
700 | return;
|
---|
701 | }
|
---|
702 | } else {
|
---|
703 | if (!rc_bit(&s->rc, &s->lzma.is_rep1[s->lzma.state])) {
|
---|
704 | tmp = s->lzma.rep1;
|
---|
705 | } else {
|
---|
706 | if (!rc_bit(&s->rc, &s->lzma.is_rep2[s->lzma.state])) {
|
---|
707 | tmp = s->lzma.rep2;
|
---|
708 | } else {
|
---|
709 | tmp = s->lzma.rep3;
|
---|
710 | s->lzma.rep3 = s->lzma.rep2;
|
---|
711 | }
|
---|
712 |
|
---|
713 | s->lzma.rep2 = s->lzma.rep1;
|
---|
714 | }
|
---|
715 |
|
---|
716 | s->lzma.rep1 = s->lzma.rep0;
|
---|
717 | s->lzma.rep0 = tmp;
|
---|
718 | }
|
---|
719 |
|
---|
720 | lzma_state_long_rep(&s->lzma.state);
|
---|
721 | lzma_len(s, &s->lzma.rep_len_dec, pos_state);
|
---|
722 | }
|
---|
723 |
|
---|
724 | /* LZMA decoder core */
|
---|
725 | static bool XZ_FUNC lzma_main(struct xz_dec_lzma2 *s)
|
---|
726 | {
|
---|
727 | uint32_t pos_state;
|
---|
728 |
|
---|
729 | /*
|
---|
730 | * If the dictionary was reached during the previous call, try to
|
---|
731 | * finish the possibly pending repeat in the dictionary.
|
---|
732 | */
|
---|
733 | if (dict_has_space(&s->dict) && s->lzma.len > 0)
|
---|
734 | dict_repeat(&s->dict, &s->lzma.len, s->lzma.rep0);
|
---|
735 |
|
---|
736 | /*
|
---|
737 | * Decode more LZMA symbols. One iteration may consume up to
|
---|
738 | * LZMA_IN_REQUIRED - 1 bytes.
|
---|
739 | */
|
---|
740 | while (dict_has_space(&s->dict) && !rc_limit_exceeded(&s->rc)) {
|
---|
741 | pos_state = s->dict.pos & s->lzma.pos_mask;
|
---|
742 |
|
---|
743 | if (!rc_bit(&s->rc, &s->lzma.is_match[
|
---|
744 | s->lzma.state][pos_state])) {
|
---|
745 | lzma_literal(s);
|
---|
746 | } else {
|
---|
747 | if (rc_bit(&s->rc, &s->lzma.is_rep[s->lzma.state]))
|
---|
748 | lzma_rep_match(s, pos_state);
|
---|
749 | else
|
---|
750 | lzma_match(s, pos_state);
|
---|
751 |
|
---|
752 | if (!dict_repeat(&s->dict, &s->lzma.len, s->lzma.rep0))
|
---|
753 | return false;
|
---|
754 | }
|
---|
755 | }
|
---|
756 |
|
---|
757 | /*
|
---|
758 | * Having the range decoder always normalized when we are outside
|
---|
759 | * this function makes it easier to correctly handle end of the chunk.
|
---|
760 | */
|
---|
761 | rc_normalize(&s->rc);
|
---|
762 |
|
---|
763 | return true;
|
---|
764 | }
|
---|
765 |
|
---|
766 | /*
|
---|
767 | * Reset the LZMA decoder and range decoder state. Dictionary is nore reset
|
---|
768 | * here, because LZMA state may be reset without resetting the dictionary.
|
---|
769 | */
|
---|
770 | static void XZ_FUNC lzma_reset(struct xz_dec_lzma2 *s)
|
---|
771 | {
|
---|
772 | uint16_t *probs;
|
---|
773 | size_t i;
|
---|
774 |
|
---|
775 | s->lzma.state = STATE_LIT_LIT;
|
---|
776 | s->lzma.rep0 = 0;
|
---|
777 | s->lzma.rep1 = 0;
|
---|
778 | s->lzma.rep2 = 0;
|
---|
779 | s->lzma.rep3 = 0;
|
---|
780 |
|
---|
781 | /*
|
---|
782 | * All probabilities are initialized to the same value. This hack
|
---|
783 | * makes the code smaller by avoiding a separate loop for each
|
---|
784 | * probability array.
|
---|
785 | *
|
---|
786 | * This could be optimized so that only that part of literal
|
---|
787 | * probabilities that are actually required. In the common case
|
---|
788 | * we would write 12 KiB less.
|
---|
789 | */
|
---|
790 | probs = s->lzma.is_match[0];
|
---|
791 | for (i = 0; i < PROBS_TOTAL; ++i)
|
---|
792 | probs[i] = RC_BIT_MODEL_TOTAL / 2;
|
---|
793 |
|
---|
794 | rc_reset(&s->rc);
|
---|
795 | }
|
---|
796 |
|
---|
797 | /*
|
---|
798 | * Decode and validate LZMA properties (lc/lp/pb) and calculate the bit masks
|
---|
799 | * from the decoded lp and pb values. On success, the LZMA decoder state is
|
---|
800 | * reset and true is returned.
|
---|
801 | */
|
---|
802 | static bool XZ_FUNC lzma_props(struct xz_dec_lzma2 *s, uint8_t props)
|
---|
803 | {
|
---|
804 | if (props > (4 * 5 + 4) * 9 + 8)
|
---|
805 | return false;
|
---|
806 |
|
---|
807 | s->lzma.pos_mask = 0;
|
---|
808 | while (props >= 9 * 5) {
|
---|
809 | props -= 9 * 5;
|
---|
810 | ++s->lzma.pos_mask;
|
---|
811 | }
|
---|
812 |
|
---|
813 | s->lzma.pos_mask = (1 << s->lzma.pos_mask) - 1;
|
---|
814 |
|
---|
815 | s->lzma.literal_pos_mask = 0;
|
---|
816 | while (props >= 9) {
|
---|
817 | props -= 9;
|
---|
818 | ++s->lzma.literal_pos_mask;
|
---|
819 | }
|
---|
820 |
|
---|
821 | s->lzma.lc = props;
|
---|
822 |
|
---|
823 | if (s->lzma.lc + s->lzma.literal_pos_mask > 4)
|
---|
824 | return false;
|
---|
825 |
|
---|
826 | s->lzma.literal_pos_mask = (1 << s->lzma.literal_pos_mask) - 1;
|
---|
827 |
|
---|
828 | lzma_reset(s);
|
---|
829 |
|
---|
830 | return true;
|
---|
831 | }
|
---|
832 |
|
---|
833 | /*********
|
---|
834 | * LZMA2 *
|
---|
835 | *********/
|
---|
836 |
|
---|
837 | /*
|
---|
838 | * The LZMA decoder assumes that if the input limit (s->rc.in_limit) hasn't
|
---|
839 | * been exceeded, it is safe to read up to LZMA_IN_REQUIRED bytes. This
|
---|
840 | * wrapper function takes care of making the LZMA decoder's assumption safe.
|
---|
841 | *
|
---|
842 | * As long as there is plenty of input left to be decoded in the current LZMA
|
---|
843 | * chunk, we decode directly from the caller-supplied input buffer until
|
---|
844 | * there's LZMA_IN_REQUIRED bytes left. Those remaining bytes are copied into
|
---|
845 | * s->temp.buf, which (hopefully) gets filled on the next call to this
|
---|
846 | * function. We decode a few bytes from the temporary buffer so that we can
|
---|
847 | * continue decoding from the caller-supplied input buffer again.
|
---|
848 | */
|
---|
849 | static bool XZ_FUNC lzma2_lzma(struct xz_dec_lzma2 *s, struct xz_buf *b)
|
---|
850 | {
|
---|
851 | size_t in_avail;
|
---|
852 | uint32_t tmp;
|
---|
853 |
|
---|
854 | in_avail = b->in_size - b->in_pos;
|
---|
855 | if (s->temp.size > 0 || s->lzma2.compressed == 0) {
|
---|
856 | tmp = 2 * LZMA_IN_REQUIRED - s->temp.size;
|
---|
857 | if (tmp > s->lzma2.compressed - s->temp.size)
|
---|
858 | tmp = s->lzma2.compressed - s->temp.size;
|
---|
859 | if (tmp > in_avail)
|
---|
860 | tmp = in_avail;
|
---|
861 |
|
---|
862 | memcpy(s->temp.buf + s->temp.size, b->in + b->in_pos, tmp);
|
---|
863 |
|
---|
864 | if (s->temp.size + tmp == s->lzma2.compressed) {
|
---|
865 | memzero(s->temp.buf + s->temp.size + tmp,
|
---|
866 | sizeof(s->temp.buf)
|
---|
867 | - s->temp.size - tmp);
|
---|
868 | s->rc.in_limit = s->temp.size + tmp;
|
---|
869 | } else if (s->temp.size + tmp < LZMA_IN_REQUIRED) {
|
---|
870 | s->temp.size += tmp;
|
---|
871 | b->in_pos += tmp;
|
---|
872 | return true;
|
---|
873 | } else {
|
---|
874 | s->rc.in_limit = s->temp.size + tmp - LZMA_IN_REQUIRED;
|
---|
875 | }
|
---|
876 |
|
---|
877 | s->rc.in = s->temp.buf;
|
---|
878 | s->rc.in_pos = 0;
|
---|
879 |
|
---|
880 | if (!lzma_main(s) || s->rc.in_pos > s->temp.size + tmp)
|
---|
881 | return false;
|
---|
882 |
|
---|
883 | s->lzma2.compressed -= s->rc.in_pos;
|
---|
884 |
|
---|
885 | if (s->rc.in_pos < s->temp.size) {
|
---|
886 | s->temp.size -= s->rc.in_pos;
|
---|
887 | memmove(s->temp.buf, s->temp.buf + s->rc.in_pos,
|
---|
888 | s->temp.size);
|
---|
889 | return true;
|
---|
890 | }
|
---|
891 |
|
---|
892 | b->in_pos += s->rc.in_pos - s->temp.size;
|
---|
893 | s->temp.size = 0;
|
---|
894 | }
|
---|
895 |
|
---|
896 | in_avail = b->in_size - b->in_pos;
|
---|
897 | if (in_avail >= LZMA_IN_REQUIRED) {
|
---|
898 | s->rc.in = b->in;
|
---|
899 | s->rc.in_pos = b->in_pos;
|
---|
900 |
|
---|
901 | if (in_avail >= s->lzma2.compressed + LZMA_IN_REQUIRED)
|
---|
902 | s->rc.in_limit = b->in_pos + s->lzma2.compressed;
|
---|
903 | else
|
---|
904 | s->rc.in_limit = b->in_size - LZMA_IN_REQUIRED;
|
---|
905 |
|
---|
906 | if (!lzma_main(s))
|
---|
907 | return false;
|
---|
908 |
|
---|
909 | in_avail = s->rc.in_pos - b->in_pos;
|
---|
910 | if (in_avail > s->lzma2.compressed)
|
---|
911 | return false;
|
---|
912 |
|
---|
913 | s->lzma2.compressed -= in_avail;
|
---|
914 | b->in_pos = s->rc.in_pos;
|
---|
915 | }
|
---|
916 |
|
---|
917 | in_avail = b->in_size - b->in_pos;
|
---|
918 | if (in_avail < LZMA_IN_REQUIRED) {
|
---|
919 | if (in_avail > s->lzma2.compressed)
|
---|
920 | in_avail = s->lzma2.compressed;
|
---|
921 |
|
---|
922 | memcpy(s->temp.buf, b->in + b->in_pos, in_avail);
|
---|
923 | s->temp.size = in_avail;
|
---|
924 | b->in_pos += in_avail;
|
---|
925 | }
|
---|
926 |
|
---|
927 | return true;
|
---|
928 | }
|
---|
929 |
|
---|
930 | /*
|
---|
931 | * Take care of the LZMA2 control layer, and forward the job of actual LZMA
|
---|
932 | * decoding or copying of uncompressed chunks to other functions.
|
---|
933 | */
|
---|
934 | XZ_EXTERN NOINLINE enum xz_ret XZ_FUNC xz_dec_lzma2_run(
|
---|
935 | struct xz_dec_lzma2 *s, struct xz_buf *b)
|
---|
936 | {
|
---|
937 | uint32_t tmp;
|
---|
938 |
|
---|
939 | while (b->in_pos < b->in_size || s->lzma2.sequence == SEQ_LZMA_RUN) {
|
---|
940 | switch (s->lzma2.sequence) {
|
---|
941 | case SEQ_CONTROL:
|
---|
942 | /*
|
---|
943 | * LZMA2 control byte
|
---|
944 | *
|
---|
945 | * Exact values:
|
---|
946 | * 0x00 End marker
|
---|
947 | * 0x01 Dictionary reset followed by
|
---|
948 | * an uncompressed chunk
|
---|
949 | * 0x02 Uncompressed chunk (no dictionary reset)
|
---|
950 | *
|
---|
951 | * Highest three bits (s->control & 0xE0):
|
---|
952 | * 0xE0 Dictionary reset, new properties and state
|
---|
953 | * reset, followed by LZMA compressed chunk
|
---|
954 | * 0xC0 New properties and state reset, followed
|
---|
955 | * by LZMA compressed chunk (no dictionary
|
---|
956 | * reset)
|
---|
957 | * 0xA0 State reset using old properties,
|
---|
958 | * followed by LZMA compressed chunk (no
|
---|
959 | * dictionary reset)
|
---|
960 | * 0x80 LZMA chunk (no dictionary or state reset)
|
---|
961 | *
|
---|
962 | * For LZMA compressed chunks, the lowest five bits
|
---|
963 | * (s->control & 1F) are the highest bits of the
|
---|
964 | * uncompressed size (bits 16-20).
|
---|
965 | *
|
---|
966 | * A new LZMA2 stream must begin with a dictionary
|
---|
967 | * reset. The first LZMA chunk must set new
|
---|
968 | * properties and reset the LZMA state.
|
---|
969 | *
|
---|
970 | * Values that don't match anything described above
|
---|
971 | * are invalid and we return XZ_DATA_ERROR.
|
---|
972 | */
|
---|
973 | tmp = b->in[b->in_pos++];
|
---|
974 |
|
---|
975 | if (tmp >= 0xE0 || tmp == 0x01) {
|
---|
976 | s->lzma2.need_props = true;
|
---|
977 | s->lzma2.need_dict_reset = false;
|
---|
978 | dict_reset(&s->dict, b);
|
---|
979 | } else if (s->lzma2.need_dict_reset) {
|
---|
980 | return XZ_DATA_ERROR;
|
---|
981 | }
|
---|
982 |
|
---|
983 | if (tmp >= 0x80) {
|
---|
984 | s->lzma2.uncompressed = (tmp & 0x1F) << 16;
|
---|
985 | s->lzma2.sequence = SEQ_UNCOMPRESSED_1;
|
---|
986 |
|
---|
987 | if (tmp >= 0xC0) {
|
---|
988 | /*
|
---|
989 | * When there are new properties,
|
---|
990 | * state reset is done at
|
---|
991 | * SEQ_PROPERTIES.
|
---|
992 | */
|
---|
993 | s->lzma2.need_props = false;
|
---|
994 | s->lzma2.next_sequence
|
---|
995 | = SEQ_PROPERTIES;
|
---|
996 |
|
---|
997 | } else if (s->lzma2.need_props) {
|
---|
998 | return XZ_DATA_ERROR;
|
---|
999 |
|
---|
1000 | } else {
|
---|
1001 | s->lzma2.next_sequence
|
---|
1002 | = SEQ_LZMA_PREPARE;
|
---|
1003 | if (tmp >= 0xA0)
|
---|
1004 | lzma_reset(s);
|
---|
1005 | }
|
---|
1006 | } else {
|
---|
1007 | if (tmp == 0x00)
|
---|
1008 | return XZ_STREAM_END;
|
---|
1009 |
|
---|
1010 | if (tmp > 0x02)
|
---|
1011 | return XZ_DATA_ERROR;
|
---|
1012 |
|
---|
1013 | s->lzma2.sequence = SEQ_COMPRESSED_0;
|
---|
1014 | s->lzma2.next_sequence = SEQ_COPY;
|
---|
1015 | }
|
---|
1016 |
|
---|
1017 | break;
|
---|
1018 |
|
---|
1019 | case SEQ_UNCOMPRESSED_1:
|
---|
1020 | s->lzma2.uncompressed
|
---|
1021 | += (uint32_t)b->in[b->in_pos++] << 8;
|
---|
1022 | s->lzma2.sequence = SEQ_UNCOMPRESSED_2;
|
---|
1023 | break;
|
---|
1024 |
|
---|
1025 | case SEQ_UNCOMPRESSED_2:
|
---|
1026 | s->lzma2.uncompressed
|
---|
1027 | += (uint32_t)b->in[b->in_pos++] + 1;
|
---|
1028 | s->lzma2.sequence = SEQ_COMPRESSED_0;
|
---|
1029 | break;
|
---|
1030 |
|
---|
1031 | case SEQ_COMPRESSED_0:
|
---|
1032 | s->lzma2.compressed
|
---|
1033 | = (uint32_t)b->in[b->in_pos++] << 8;
|
---|
1034 | s->lzma2.sequence = SEQ_COMPRESSED_1;
|
---|
1035 | break;
|
---|
1036 |
|
---|
1037 | case SEQ_COMPRESSED_1:
|
---|
1038 | s->lzma2.compressed
|
---|
1039 | += (uint32_t)b->in[b->in_pos++] + 1;
|
---|
1040 | s->lzma2.sequence = s->lzma2.next_sequence;
|
---|
1041 | break;
|
---|
1042 |
|
---|
1043 | case SEQ_PROPERTIES:
|
---|
1044 | if (!lzma_props(s, b->in[b->in_pos++]))
|
---|
1045 | return XZ_DATA_ERROR;
|
---|
1046 |
|
---|
1047 | s->lzma2.sequence = SEQ_LZMA_PREPARE;
|
---|
1048 |
|
---|
1049 | case SEQ_LZMA_PREPARE:
|
---|
1050 | if (s->lzma2.compressed < RC_INIT_BYTES)
|
---|
1051 | return XZ_DATA_ERROR;
|
---|
1052 |
|
---|
1053 | if (!rc_read_init(&s->rc, b))
|
---|
1054 | return XZ_OK;
|
---|
1055 |
|
---|
1056 | s->lzma2.compressed -= RC_INIT_BYTES;
|
---|
1057 | s->lzma2.sequence = SEQ_LZMA_RUN;
|
---|
1058 |
|
---|
1059 | case SEQ_LZMA_RUN:
|
---|
1060 | /*
|
---|
1061 | * Set dictionary limit to indicate how much we want
|
---|
1062 | * to be encoded at maximum. Decode new data into the
|
---|
1063 | * dictionary. Flush the new data from dictionary to
|
---|
1064 | * b->out. Check if we finished decoding this chunk.
|
---|
1065 | * In case the dictionary got full but we didn't fill
|
---|
1066 | * the output buffer yet, we may run this loop
|
---|
1067 | * multiple times without changing s->lzma2.sequence.
|
---|
1068 | */
|
---|
1069 | dict_limit(&s->dict, min_t(size_t,
|
---|
1070 | b->out_size - b->out_pos,
|
---|
1071 | s->lzma2.uncompressed));
|
---|
1072 | if (!lzma2_lzma(s, b))
|
---|
1073 | return XZ_DATA_ERROR;
|
---|
1074 |
|
---|
1075 | s->lzma2.uncompressed -= dict_flush(&s->dict, b);
|
---|
1076 |
|
---|
1077 | if (s->lzma2.uncompressed == 0) {
|
---|
1078 | if (s->lzma2.compressed > 0 || s->lzma.len > 0
|
---|
1079 | || !rc_is_finished(&s->rc))
|
---|
1080 | return XZ_DATA_ERROR;
|
---|
1081 |
|
---|
1082 | rc_reset(&s->rc);
|
---|
1083 | s->lzma2.sequence = SEQ_CONTROL;
|
---|
1084 |
|
---|
1085 | } else if (b->out_pos == b->out_size
|
---|
1086 | || (b->in_pos == b->in_size
|
---|
1087 | && s->temp.size
|
---|
1088 | < s->lzma2.compressed)) {
|
---|
1089 | return XZ_OK;
|
---|
1090 | }
|
---|
1091 |
|
---|
1092 | break;
|
---|
1093 |
|
---|
1094 | case SEQ_COPY:
|
---|
1095 | dict_uncompressed(&s->dict, b, &s->lzma2.compressed);
|
---|
1096 | if (s->lzma2.compressed > 0)
|
---|
1097 | return XZ_OK;
|
---|
1098 |
|
---|
1099 | s->lzma2.sequence = SEQ_CONTROL;
|
---|
1100 | break;
|
---|
1101 | }
|
---|
1102 | }
|
---|
1103 |
|
---|
1104 | return XZ_OK;
|
---|
1105 | }
|
---|
1106 |
|
---|
1107 | XZ_EXTERN struct xz_dec_lzma2 * XZ_FUNC xz_dec_lzma2_create(
|
---|
1108 | enum xz_mode mode, uint32_t dict_max)
|
---|
1109 | {
|
---|
1110 | struct xz_dec_lzma2 *s = kmalloc(sizeof(*s), GFP_KERNEL);
|
---|
1111 | if (s == NULL)
|
---|
1112 | return NULL;
|
---|
1113 |
|
---|
1114 | s->dict.mode = mode;
|
---|
1115 | s->dict.size_max = dict_max;
|
---|
1116 |
|
---|
1117 | if (DEC_IS_PREALLOC(mode)) {
|
---|
1118 | s->dict.buf = vmalloc(dict_max);
|
---|
1119 | if (s->dict.buf == NULL) {
|
---|
1120 | kfree(s);
|
---|
1121 | return NULL;
|
---|
1122 | }
|
---|
1123 | } else if (DEC_IS_DYNALLOC(mode)) {
|
---|
1124 | s->dict.buf = NULL;
|
---|
1125 | s->dict.allocated = 0;
|
---|
1126 | }
|
---|
1127 |
|
---|
1128 | return s;
|
---|
1129 | }
|
---|
1130 |
|
---|
1131 | XZ_EXTERN enum xz_ret XZ_FUNC xz_dec_lzma2_reset(
|
---|
1132 | struct xz_dec_lzma2 *s, uint8_t props)
|
---|
1133 | {
|
---|
1134 | /* This limits dictionary size to 3 GiB to keep parsing simpler. */
|
---|
1135 | if (props > 39)
|
---|
1136 | return XZ_OPTIONS_ERROR;
|
---|
1137 |
|
---|
1138 | s->dict.size = 2 + (props & 1);
|
---|
1139 | s->dict.size <<= (props >> 1) + 11;
|
---|
1140 |
|
---|
1141 | if (DEC_IS_MULTI(s->dict.mode)) {
|
---|
1142 | if (s->dict.size > s->dict.size_max)
|
---|
1143 | return XZ_MEMLIMIT_ERROR;
|
---|
1144 |
|
---|
1145 | s->dict.end = s->dict.size;
|
---|
1146 |
|
---|
1147 | if (DEC_IS_DYNALLOC(s->dict.mode)) {
|
---|
1148 | if (s->dict.allocated < s->dict.size) {
|
---|
1149 | vfree(s->dict.buf);
|
---|
1150 | s->dict.buf = vmalloc(s->dict.size);
|
---|
1151 | if (s->dict.buf == NULL) {
|
---|
1152 | s->dict.allocated = 0;
|
---|
1153 | return XZ_MEM_ERROR;
|
---|
1154 | }
|
---|
1155 | }
|
---|
1156 | }
|
---|
1157 | }
|
---|
1158 |
|
---|
1159 | s->lzma.len = 0;
|
---|
1160 |
|
---|
1161 | s->lzma2.sequence = SEQ_CONTROL;
|
---|
1162 | s->lzma2.need_dict_reset = true;
|
---|
1163 |
|
---|
1164 | s->temp.size = 0;
|
---|
1165 |
|
---|
1166 | return XZ_OK;
|
---|
1167 | }
|
---|
1168 |
|
---|
1169 | XZ_EXTERN void XZ_FUNC xz_dec_lzma2_end(struct xz_dec_lzma2 *s)
|
---|
1170 | {
|
---|
1171 | if (DEC_IS_MULTI(s->dict.mode))
|
---|
1172 | vfree(s->dict.buf);
|
---|
1173 |
|
---|
1174 | kfree(s);
|
---|
1175 | }
|
---|