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| Rev | Author | Line No. | Line |
|---|---|---|---|
| 4349 | Serge | 1 | /* inflate.h -- internal inflate state definition |
| 2 | * Copyright (C) 1995-2009 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 | |||
| 6 | /* WARNING: this file should *not* be used by applications. It is |
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| 7 | part of the implementation of the compression library and is |
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| 8 | subject to change. Applications should only use zlib.h. |
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| 9 | */ |
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| 10 | |||
| 11 | /* define NO_GZIP when compiling if you want to disable gzip header and |
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| 12 | trailer decoding by inflate(). NO_GZIP would be used to avoid linking in |
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| 13 | the crc code when it is not needed. For shared libraries, gzip decoding |
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| 14 | should be left enabled. */ |
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| 15 | #ifndef NO_GZIP |
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| 16 | # define GUNZIP |
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| 17 | #endif |
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| 18 | |||
| 19 | /* Possible inflate modes between inflate() calls */ |
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| 20 | typedef enum { |
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| 21 | HEAD, /* i: waiting for magic header */ |
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| 22 | FLAGS, /* i: waiting for method and flags (gzip) */ |
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| 23 | TIME, /* i: waiting for modification time (gzip) */ |
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| 24 | OS, /* i: waiting for extra flags and operating system (gzip) */ |
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| 25 | EXLEN, /* i: waiting for extra length (gzip) */ |
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| 26 | EXTRA, /* i: waiting for extra bytes (gzip) */ |
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| 27 | NAME, /* i: waiting for end of file name (gzip) */ |
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| 28 | COMMENT, /* i: waiting for end of comment (gzip) */ |
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| 29 | HCRC, /* i: waiting for header crc (gzip) */ |
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| 30 | DICTID, /* i: waiting for dictionary check value */ |
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| 31 | DICT, /* waiting for inflateSetDictionary() call */ |
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| 32 | TYPE, /* i: waiting for type bits, including last-flag bit */ |
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| 33 | TYPEDO, /* i: same, but skip check to exit inflate on new block */ |
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| 34 | STORED, /* i: waiting for stored size (length and complement) */ |
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| 35 | COPY_, /* i/o: same as COPY below, but only first time in */ |
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| 36 | COPY, /* i/o: waiting for input or output to copy stored block */ |
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| 37 | TABLE, /* i: waiting for dynamic block table lengths */ |
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| 38 | LENLENS, /* i: waiting for code length code lengths */ |
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| 39 | CODELENS, /* i: waiting for length/lit and distance code lengths */ |
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| 40 | LEN_, /* i: same as LEN below, but only first time in */ |
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| 41 | LEN, /* i: waiting for length/lit/eob code */ |
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| 42 | LENEXT, /* i: waiting for length extra bits */ |
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| 43 | DIST, /* i: waiting for distance code */ |
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| 44 | DISTEXT, /* i: waiting for distance extra bits */ |
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| 45 | MATCH, /* o: waiting for output space to copy string */ |
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| 46 | LIT, /* o: waiting for output space to write literal */ |
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| 47 | CHECK, /* i: waiting for 32-bit check value */ |
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| 48 | LENGTH, /* i: waiting for 32-bit length (gzip) */ |
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| 49 | DONE, /* finished check, done -- remain here until reset */ |
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| 50 | BAD, /* got a data error -- remain here until reset */ |
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| 51 | MEM, /* got an inflate() memory error -- remain here until reset */ |
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| 52 | SYNC /* looking for synchronization bytes to restart inflate() */ |
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| 53 | } inflate_mode; |
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| 54 | |||
| 55 | /* |
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| 56 | State transitions between above modes - |
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| 57 | |||
| 58 | (most modes can go to BAD or MEM on error -- not shown for clarity) |
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| 59 | |||
| 60 | Process header: |
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| 61 | HEAD -> (gzip) or (zlib) or (raw) |
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| 62 | (gzip) -> FLAGS -> TIME -> OS -> EXLEN -> EXTRA -> NAME -> COMMENT -> |
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| 63 | HCRC -> TYPE |
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| 64 | (zlib) -> DICTID or TYPE |
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| 65 | DICTID -> DICT -> TYPE |
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| 66 | (raw) -> TYPEDO |
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| 67 | Read deflate blocks: |
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| 68 | TYPE -> TYPEDO -> STORED or TABLE or LEN_ or CHECK |
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| 69 | STORED -> COPY_ -> COPY -> TYPE |
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| 70 | TABLE -> LENLENS -> CODELENS -> LEN_ |
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| 71 | LEN_ -> LEN |
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| 72 | Read deflate codes in fixed or dynamic block: |
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| 73 | LEN -> LENEXT or LIT or TYPE |
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| 74 | LENEXT -> DIST -> DISTEXT -> MATCH -> LEN |
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| 75 | LIT -> LEN |
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| 76 | Process trailer: |
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| 77 | CHECK -> LENGTH -> DONE |
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| 78 | */ |
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| 79 | |||
| 80 | /* state maintained between inflate() calls. Approximately 10K bytes. */ |
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| 81 | struct inflate_state { |
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| 82 | inflate_mode mode; /* current inflate mode */ |
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| 83 | int last; /* true if processing last block */ |
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| 84 | int wrap; /* bit 0 true for zlib, bit 1 true for gzip */ |
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| 85 | int havedict; /* true if dictionary provided */ |
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| 86 | int flags; /* gzip header method and flags (0 if zlib) */ |
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| 87 | unsigned dmax; /* zlib header max distance (INFLATE_STRICT) */ |
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| 88 | unsigned long check; /* protected copy of check value */ |
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| 89 | unsigned long total; /* protected copy of output count */ |
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| 90 | gz_headerp head; /* where to save gzip header information */ |
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| 91 | /* sliding window */ |
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| 92 | unsigned wbits; /* log base 2 of requested window size */ |
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| 93 | unsigned wsize; /* window size or zero if not using window */ |
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| 94 | unsigned whave; /* valid bytes in the window */ |
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| 95 | unsigned wnext; /* window write index */ |
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| 96 | unsigned char FAR *window; /* allocated sliding window, if needed */ |
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| 97 | /* bit accumulator */ |
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| 98 | unsigned long hold; /* input bit accumulator */ |
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| 99 | unsigned bits; /* number of bits in "in" */ |
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| 100 | /* for string and stored block copying */ |
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| 101 | unsigned length; /* literal or length of data to copy */ |
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| 102 | unsigned offset; /* distance back to copy string from */ |
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| 103 | /* for table and code decoding */ |
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| 104 | unsigned extra; /* extra bits needed */ |
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| 105 | /* fixed and dynamic code tables */ |
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| 106 | code const FAR *lencode; /* starting table for length/literal codes */ |
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| 107 | code const FAR *distcode; /* starting table for distance codes */ |
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| 108 | unsigned lenbits; /* index bits for lencode */ |
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| 109 | unsigned distbits; /* index bits for distcode */ |
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| 110 | /* dynamic table building */ |
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| 111 | unsigned ncode; /* number of code length code lengths */ |
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| 112 | unsigned nlen; /* number of length code lengths */ |
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| 113 | unsigned ndist; /* number of distance code lengths */ |
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| 114 | unsigned have; /* number of code lengths in lens[] */ |
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| 115 | code FAR *next; /* next available space in codes[] */ |
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| 116 | unsigned short lens[320]; /* temporary storage for code lengths */ |
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| 117 | unsigned short work[288]; /* work area for code table building */ |
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| 118 | code codes[ENOUGH]; /* space for code tables */ |
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| 119 | int sane; /* if false, allow invalid distance too far */ |
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| 120 | int back; /* bits back of last unprocessed length/lit */ |
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| 121 | unsigned was; /* initial length of match */ |
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| 122 | }; |