1 /* |
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2 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
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3 * |
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4 * This code is free software; you can redistribute it and/or modify it |
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5 * under the terms of the GNU General Public License version 2 only, as |
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6 * published by the Free Software Foundation. Oracle designates this |
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7 * particular file as subject to the "Classpath" exception as provided |
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8 * by Oracle in the LICENSE file that accompanied this code. |
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9 * |
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10 * This code is distributed in the hope that it will be useful, but WITHOUT |
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11 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
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12 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
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13 * version 2 for more details (a copy is included in the LICENSE file that |
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14 * accompanied this code). |
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15 * |
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16 * You should have received a copy of the GNU General Public License version |
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17 * 2 along with this work; if not, write to the Free Software Foundation, |
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18 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
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19 * |
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20 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
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21 * or visit www.oracle.com if you need additional information or have any |
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22 * questions. |
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23 */ |
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24 |
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25 /* inflate.h -- internal inflate state definition |
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26 * Copyright (C) 1995-2009 Mark Adler |
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27 * For conditions of distribution and use, see copyright notice in zlib.h |
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28 */ |
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29 |
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30 /* WARNING: this file should *not* be used by applications. It is |
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31 part of the implementation of the compression library and is |
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32 subject to change. Applications should only use zlib.h. |
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33 */ |
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34 |
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35 /* define NO_GZIP when compiling if you want to disable gzip header and |
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36 trailer decoding by inflate(). NO_GZIP would be used to avoid linking in |
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37 the crc code when it is not needed. For shared libraries, gzip decoding |
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38 should be left enabled. */ |
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39 #ifndef NO_GZIP |
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40 # define GUNZIP |
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41 #endif |
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42 |
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43 /* Possible inflate modes between inflate() calls */ |
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44 typedef enum { |
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45 HEAD, /* i: waiting for magic header */ |
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46 FLAGS, /* i: waiting for method and flags (gzip) */ |
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47 TIME, /* i: waiting for modification time (gzip) */ |
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48 OS, /* i: waiting for extra flags and operating system (gzip) */ |
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49 EXLEN, /* i: waiting for extra length (gzip) */ |
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50 EXTRA, /* i: waiting for extra bytes (gzip) */ |
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51 NAME, /* i: waiting for end of file name (gzip) */ |
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52 COMMENT, /* i: waiting for end of comment (gzip) */ |
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53 HCRC, /* i: waiting for header crc (gzip) */ |
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54 DICTID, /* i: waiting for dictionary check value */ |
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55 DICT, /* waiting for inflateSetDictionary() call */ |
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56 TYPE, /* i: waiting for type bits, including last-flag bit */ |
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57 TYPEDO, /* i: same, but skip check to exit inflate on new block */ |
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58 STORED, /* i: waiting for stored size (length and complement) */ |
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59 COPY_, /* i/o: same as COPY below, but only first time in */ |
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60 COPY, /* i/o: waiting for input or output to copy stored block */ |
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61 TABLE, /* i: waiting for dynamic block table lengths */ |
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62 LENLENS, /* i: waiting for code length code lengths */ |
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63 CODELENS, /* i: waiting for length/lit and distance code lengths */ |
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64 LEN_, /* i: same as LEN below, but only first time in */ |
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65 LEN, /* i: waiting for length/lit/eob code */ |
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66 LENEXT, /* i: waiting for length extra bits */ |
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67 DIST, /* i: waiting for distance code */ |
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68 DISTEXT, /* i: waiting for distance extra bits */ |
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69 MATCH, /* o: waiting for output space to copy string */ |
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70 LIT, /* o: waiting for output space to write literal */ |
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71 CHECK, /* i: waiting for 32-bit check value */ |
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72 LENGTH, /* i: waiting for 32-bit length (gzip) */ |
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73 DONE, /* finished check, done -- remain here until reset */ |
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74 BAD, /* got a data error -- remain here until reset */ |
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75 MEM, /* got an inflate() memory error -- remain here until reset */ |
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76 SYNC /* looking for synchronization bytes to restart inflate() */ |
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77 } inflate_mode; |
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78 |
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79 /* |
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80 State transitions between above modes - |
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81 |
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82 (most modes can go to BAD or MEM on error -- not shown for clarity) |
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83 |
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84 Process header: |
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85 HEAD -> (gzip) or (zlib) or (raw) |
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86 (gzip) -> FLAGS -> TIME -> OS -> EXLEN -> EXTRA -> NAME -> COMMENT -> |
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87 HCRC -> TYPE |
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88 (zlib) -> DICTID or TYPE |
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89 DICTID -> DICT -> TYPE |
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90 (raw) -> TYPEDO |
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91 Read deflate blocks: |
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92 TYPE -> TYPEDO -> STORED or TABLE or LEN_ or CHECK |
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93 STORED -> COPY_ -> COPY -> TYPE |
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94 TABLE -> LENLENS -> CODELENS -> LEN_ |
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95 LEN_ -> LEN |
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96 Read deflate codes in fixed or dynamic block: |
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97 LEN -> LENEXT or LIT or TYPE |
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98 LENEXT -> DIST -> DISTEXT -> MATCH -> LEN |
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99 LIT -> LEN |
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100 Process trailer: |
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101 CHECK -> LENGTH -> DONE |
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102 */ |
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103 |
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104 /* state maintained between inflate() calls. Approximately 10K bytes. */ |
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105 struct inflate_state { |
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106 inflate_mode mode; /* current inflate mode */ |
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107 int last; /* true if processing last block */ |
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108 int wrap; /* bit 0 true for zlib, bit 1 true for gzip */ |
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109 int havedict; /* true if dictionary provided */ |
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110 int flags; /* gzip header method and flags (0 if zlib) */ |
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111 unsigned dmax; /* zlib header max distance (INFLATE_STRICT) */ |
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112 unsigned long check; /* protected copy of check value */ |
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113 unsigned long total; /* protected copy of output count */ |
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114 gz_headerp head; /* where to save gzip header information */ |
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115 /* sliding window */ |
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116 unsigned wbits; /* log base 2 of requested window size */ |
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117 unsigned wsize; /* window size or zero if not using window */ |
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118 unsigned whave; /* valid bytes in the window */ |
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119 unsigned wnext; /* window write index */ |
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120 unsigned char FAR *window; /* allocated sliding window, if needed */ |
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121 /* bit accumulator */ |
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122 unsigned long hold; /* input bit accumulator */ |
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123 unsigned bits; /* number of bits in "in" */ |
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124 /* for string and stored block copying */ |
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125 unsigned length; /* literal or length of data to copy */ |
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126 unsigned offset; /* distance back to copy string from */ |
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127 /* for table and code decoding */ |
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128 unsigned extra; /* extra bits needed */ |
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129 /* fixed and dynamic code tables */ |
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130 code const FAR *lencode; /* starting table for length/literal codes */ |
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131 code const FAR *distcode; /* starting table for distance codes */ |
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132 unsigned lenbits; /* index bits for lencode */ |
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133 unsigned distbits; /* index bits for distcode */ |
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134 /* dynamic table building */ |
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135 unsigned ncode; /* number of code length code lengths */ |
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136 unsigned nlen; /* number of length code lengths */ |
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137 unsigned ndist; /* number of distance code lengths */ |
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138 unsigned have; /* number of code lengths in lens[] */ |
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139 code FAR *next; /* next available space in codes[] */ |
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140 unsigned short lens[320]; /* temporary storage for code lengths */ |
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141 unsigned short work[288]; /* work area for code table building */ |
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142 code codes[ENOUGH]; /* space for code tables */ |
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143 int sane; /* if false, allow invalid distance too far */ |
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144 int back; /* bits back of last unprocessed length/lit */ |
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145 unsigned was; /* initial length of match */ |
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146 }; |
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