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1 /* inflate.c -- zlib interface to inflate modules |
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2 * Copyright (C) 1995-2002 Mark Adler |
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3 * For conditions of distribution and use, see copyright notice in zlib.h |
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4 */ |
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5 |
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6 #include "zutil.h" |
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7 #include "infblock.h" |
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8 |
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9 #define DONE INFLATE_DONE |
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10 #define BAD INFLATE_BAD |
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11 |
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12 typedef enum { |
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13 METHOD, /* waiting for method byte */ |
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14 FLAG, /* waiting for flag byte */ |
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15 DICT4, /* four dictionary check bytes to go */ |
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16 DICT3, /* three dictionary check bytes to go */ |
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17 DICT2, /* two dictionary check bytes to go */ |
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18 DICT1, /* one dictionary check byte to go */ |
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19 DICT0, /* waiting for inflateSetDictionary */ |
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20 BLOCKS, /* decompressing blocks */ |
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21 CHECK4, /* four check bytes to go */ |
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22 CHECK3, /* three check bytes to go */ |
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23 CHECK2, /* two check bytes to go */ |
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24 CHECK1, /* one check byte to go */ |
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25 DONE, /* finished check, done */ |
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26 BAD} /* got an error--stay here */ |
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27 inflate_mode; |
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28 |
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29 /* inflate private state */ |
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30 struct internal_state { |
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31 |
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32 /* mode */ |
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33 inflate_mode mode; /* current inflate mode */ |
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34 |
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35 /* mode dependent information */ |
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36 union { |
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37 uInt method; /* if FLAGS, method byte */ |
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38 struct { |
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39 uLong was; /* computed check value */ |
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40 uLong need; /* stream check value */ |
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41 } check; /* if CHECK, check values to compare */ |
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42 uInt marker; /* if BAD, inflateSync's marker bytes count */ |
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43 } sub; /* submode */ |
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44 |
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45 /* mode independent information */ |
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46 int nowrap; /* flag for no wrapper */ |
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47 uInt wbits; /* log2(window size) (8..15, defaults to 15) */ |
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48 inflate_blocks_statef |
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49 *blocks; /* current inflate_blocks state */ |
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50 |
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51 }; |
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52 |
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53 |
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54 ZEXPORT(int) inflateReset( /* z) */ |
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55 z_streamp z ) |
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56 { |
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57 if (z == Z_NULL || z->state == Z_NULL) |
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58 return Z_STREAM_ERROR; |
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59 z->total_in = z->total_out = 0; |
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60 z->msg = Z_NULL; |
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61 z->state->mode = z->state->nowrap ? BLOCKS : METHOD; |
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62 inflate_blocks_reset(z->state->blocks, z, Z_NULL); |
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63 Tracev((stderr, "inflate: reset\n")); |
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64 return Z_OK; |
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65 } |
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66 |
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67 |
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68 ZEXPORT(int) inflateEnd( /* z) */ |
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69 z_streamp z ) |
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70 { |
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71 if (z == Z_NULL || z->state == Z_NULL || z->zfree == Z_NULL) |
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72 return Z_STREAM_ERROR; |
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73 if (z->state->blocks != Z_NULL) |
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74 inflate_blocks_free(z->state->blocks, z); |
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75 ZFREE(z, z->state); |
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76 z->state = Z_NULL; |
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77 Tracev((stderr, "inflate: end\n")); |
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78 return Z_OK; |
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79 } |
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80 |
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81 |
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82 ZEXPORT(int) inflateInit2_( /* z, w, version, stream_size) */ |
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83 z_streamp z, |
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84 int w, |
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85 const char *version, |
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86 int stream_size ) |
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87 { |
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88 if (version == Z_NULL || version[0] != ZLIB_VERSION[0] || |
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89 stream_size != sizeof(z_stream)) |
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90 return Z_VERSION_ERROR; |
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91 |
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92 /* initialize state */ |
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93 if (z == Z_NULL) |
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94 return Z_STREAM_ERROR; |
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95 z->msg = Z_NULL; |
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96 if (z->zalloc == Z_NULL) |
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97 { |
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98 z->zalloc = zcalloc; |
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99 z->opaque = (voidpf)0; |
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100 } |
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101 if (z->zfree == Z_NULL) z->zfree = zcfree; |
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102 if ((z->state = (struct internal_state FAR *) |
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103 ZALLOC(z,1,sizeof(struct internal_state))) == Z_NULL) |
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104 return Z_MEM_ERROR; |
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105 z->state->blocks = Z_NULL; |
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106 |
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107 /* handle undocumented nowrap option (no zlib header or check) */ |
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108 z->state->nowrap = 0; |
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109 if (w < 0) |
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110 { |
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111 w = - w; |
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112 z->state->nowrap = 1; |
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113 } |
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114 |
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115 /* set window size */ |
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116 if (w < 8 || w > 15) |
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117 { |
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118 inflateEnd(z); |
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119 return Z_STREAM_ERROR; |
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120 } |
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121 z->state->wbits = (uInt)w; |
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122 |
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123 /* create inflate_blocks state */ |
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124 if ((z->state->blocks = |
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125 inflate_blocks_new(z, z->state->nowrap ? Z_NULL : adler32, (uInt)1 << w)) |
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126 == Z_NULL) |
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127 { |
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128 inflateEnd(z); |
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129 return Z_MEM_ERROR; |
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130 } |
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131 Tracev((stderr, "inflate: allocated\n")); |
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132 |
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133 /* reset state */ |
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134 inflateReset(z); |
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135 return Z_OK; |
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136 } |
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137 |
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138 |
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139 |
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140 #undef NEEDBYTE |
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141 #define NEEDBYTE {if(z->avail_in==0)return r;r=f;} |
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142 |
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143 #undef NEXTBYTE |
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144 #define NEXTBYTE (z->avail_in--,z->total_in++,*z->next_in++) |
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145 |
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146 |
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147 ZEXPORT(int) inflate( /* z, f) */ |
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148 z_streamp z, |
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149 int f ) |
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150 { |
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151 int r; |
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152 uInt b; |
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153 |
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154 if (z == Z_NULL || z->state == Z_NULL || z->next_in == Z_NULL) |
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155 return Z_STREAM_ERROR; |
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156 f = f == Z_FINISH ? Z_BUF_ERROR : Z_OK; |
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157 r = Z_BUF_ERROR; |
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158 while (1) switch (z->state->mode) |
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159 { |
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160 case METHOD: |
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161 NEEDBYTE |
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162 if (((z->state->sub.method = NEXTBYTE) & 0xf) != Z_DEFLATED) |
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163 { |
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164 z->state->mode = BAD; |
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165 z->msg = (char*)"unknown compression method"; |
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166 z->state->sub.marker = 5; /* can't try inflateSync */ |
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167 break; |
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168 } |
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169 if ((z->state->sub.method >> 4) + 8 > z->state->wbits) |
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170 { |
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171 z->state->mode = BAD; |
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172 z->msg = (char*)"invalid window size"; |
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173 z->state->sub.marker = 5; /* can't try inflateSync */ |
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174 break; |
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175 } |
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176 z->state->mode = FLAG; |
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177 case FLAG: |
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178 NEEDBYTE |
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179 b = NEXTBYTE; |
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180 if (((z->state->sub.method << 8) + b) % 31) |
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181 { |
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182 z->state->mode = BAD; |
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183 z->msg = (char*)"incorrect header check"; |
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184 z->state->sub.marker = 5; /* can't try inflateSync */ |
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185 break; |
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186 } |
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187 Tracev((stderr, "inflate: zlib header ok\n")); |
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188 if (!(b & PRESET_DICT)) |
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189 { |
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190 z->state->mode = BLOCKS; |
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191 break; |
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192 } |
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193 z->state->mode = DICT4; |
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194 case DICT4: |
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195 NEEDBYTE |
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196 z->state->sub.check.need = (uLong)NEXTBYTE << 24; |
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197 z->state->mode = DICT3; |
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198 case DICT3: |
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199 NEEDBYTE |
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200 z->state->sub.check.need += (uLong)NEXTBYTE << 16; |
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201 z->state->mode = DICT2; |
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202 case DICT2: |
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203 NEEDBYTE |
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204 z->state->sub.check.need += (uLong)NEXTBYTE << 8; |
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205 z->state->mode = DICT1; |
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206 case DICT1: |
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207 NEEDBYTE |
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208 z->state->sub.check.need += (uLong)NEXTBYTE; |
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209 z->adler = z->state->sub.check.need; |
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210 z->state->mode = DICT0; |
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211 return Z_NEED_DICT; |
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212 case DICT0: |
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213 z->state->mode = BAD; |
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214 z->msg = (char*)"need dictionary"; |
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215 z->state->sub.marker = 0; /* can try inflateSync */ |
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216 return Z_STREAM_ERROR; |
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217 case BLOCKS: |
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218 r = inflate_blocks(z->state->blocks, z, r); |
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219 if (r == Z_DATA_ERROR) |
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220 { |
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221 z->state->mode = BAD; |
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222 z->state->sub.marker = 0; /* can try inflateSync */ |
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223 break; |
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224 } |
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225 if (r == Z_OK) |
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226 r = f; |
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227 if (r != Z_STREAM_END) |
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228 return r; |
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229 r = f; |
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230 inflate_blocks_reset(z->state->blocks, z, &z->state->sub.check.was); |
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231 if (z->state->nowrap) |
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232 { |
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233 z->state->mode = DONE; |
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234 break; |
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235 } |
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236 z->state->mode = CHECK4; |
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237 case CHECK4: |
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238 NEEDBYTE |
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239 z->state->sub.check.need = (uLong)NEXTBYTE << 24; |
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240 z->state->mode = CHECK3; |
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241 case CHECK3: |
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242 NEEDBYTE |
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243 z->state->sub.check.need += (uLong)NEXTBYTE << 16; |
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244 z->state->mode = CHECK2; |
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245 case CHECK2: |
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246 NEEDBYTE |
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247 z->state->sub.check.need += (uLong)NEXTBYTE << 8; |
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248 z->state->mode = CHECK1; |
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249 case CHECK1: |
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250 NEEDBYTE |
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251 z->state->sub.check.need += (uLong)NEXTBYTE; |
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252 |
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253 if (z->state->sub.check.was != z->state->sub.check.need) |
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254 { |
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255 z->state->mode = BAD; |
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256 z->msg = (char*)"incorrect data check"; |
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257 z->state->sub.marker = 5; /* can't try inflateSync */ |
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258 break; |
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259 } |
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260 Tracev((stderr, "inflate: zlib check ok\n")); |
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261 z->state->mode = DONE; |
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262 case DONE: |
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263 return Z_STREAM_END; |
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264 case BAD: |
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265 return Z_DATA_ERROR; |
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266 default: |
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267 return Z_STREAM_ERROR; |
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268 } |
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269 #ifdef NEED_DUMMY_RETURN |
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270 return Z_STREAM_ERROR; /* Some dumb compilers complain without this */ |
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271 #endif |
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272 } |
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273 |