inflate.h revision 272461
1226031Sstas/* inflate.h -- internal inflate state definition 2226031Sstas * Copyright (C) 1995-2009 Mark Adler 3226031Sstas * For conditions of distribution and use, see copyright notice in zlib.h 4226031Sstas */ 5226031Sstas 6226031Sstas/* WARNING: this file should *not* be used by applications. It is 7226031Sstas part of the implementation of the compression library and is 8226031Sstas subject to change. Applications should only use zlib.h. 9226031Sstas */ 10226031Sstas 11226031Sstas/* define NO_GZIP when compiling if you want to disable gzip header and 12226031Sstas trailer decoding by inflate(). NO_GZIP would be used to avoid linking in 13226031Sstas the crc code when it is not needed. For shared libraries, gzip decoding 14226031Sstas should be left enabled. */ 15226031Sstas#ifndef NO_GZIP 16226031Sstas# define GUNZIP 17226031Sstas#endif 18226031Sstas 19226031Sstas/* Possible inflate modes between inflate() calls */ 20226031Sstastypedef enum { 21226031Sstas HEAD, /* i: waiting for magic header */ 22226031Sstas FLAGS, /* i: waiting for method and flags (gzip) */ 23226031Sstas TIME, /* i: waiting for modification time (gzip) */ 24226031Sstas OS, /* i: waiting for extra flags and operating system (gzip) */ 25226031Sstas EXLEN, /* i: waiting for extra length (gzip) */ 26226031Sstas EXTRA, /* i: waiting for extra bytes (gzip) */ 27226031Sstas NAME, /* i: waiting for end of file name (gzip) */ 28226031Sstas COMMENT, /* i: waiting for end of comment (gzip) */ 29226031Sstas HCRC, /* i: waiting for header crc (gzip) */ 30226031Sstas DICTID, /* i: waiting for dictionary check value */ 31226031Sstas DICT, /* waiting for inflateSetDictionary() call */ 32226031Sstas TYPE, /* i: waiting for type bits, including last-flag bit */ 33226031Sstas TYPEDO, /* i: same, but skip check to exit inflate on new block */ 34226031Sstas STORED, /* i: waiting for stored size (length and complement) */ 35226031Sstas COPY_, /* i/o: same as COPY below, but only first time in */ 36226031Sstas COPY, /* i/o: waiting for input or output to copy stored block */ 37226031Sstas TABLE, /* i: waiting for dynamic block table lengths */ 38226031Sstas LENLENS, /* i: waiting for code length code lengths */ 39226031Sstas CODELENS, /* i: waiting for length/lit and distance code lengths */ 40226031Sstas LEN_, /* i: same as LEN below, but only first time in */ 41226031Sstas LEN, /* i: waiting for length/lit/eob code */ 42226031Sstas LENEXT, /* i: waiting for length extra bits */ 43226031Sstas DIST, /* i: waiting for distance code */ 44226031Sstas DISTEXT, /* i: waiting for distance extra bits */ 45226031Sstas MATCH, /* o: waiting for output space to copy string */ 46226031Sstas LIT, /* o: waiting for output space to write literal */ 47226031Sstas CHECK, /* i: waiting for 32-bit check value */ 48226031Sstas LENGTH, /* i: waiting for 32-bit length (gzip) */ 49226031Sstas DONE, /* finished check, done -- remain here until reset */ 50226031Sstas BAD, /* got a data error -- remain here until reset */ 51226031Sstas MEM, /* got an inflate() memory error -- remain here until reset */ 52226031Sstas SYNC /* looking for synchronization bytes to restart inflate() */ 53226031Sstas} inflate_mode; 54226031Sstas 55226031Sstas/* 56226031Sstas State transitions between above modes - 57226031Sstas 58226031Sstas (most modes can go to BAD or MEM on error -- not shown for clarity) 59226031Sstas 60226031Sstas Process header: 61226031Sstas HEAD -> (gzip) or (zlib) or (raw) 62226031Sstas (gzip) -> FLAGS -> TIME -> OS -> EXLEN -> EXTRA -> NAME -> COMMENT -> 63226031Sstas HCRC -> TYPE 64226031Sstas (zlib) -> DICTID or TYPE 65 DICTID -> DICT -> TYPE 66 (raw) -> TYPEDO 67 Read deflate blocks: 68 TYPE -> TYPEDO -> STORED or TABLE or LEN_ or CHECK 69 STORED -> COPY_ -> COPY -> TYPE 70 TABLE -> LENLENS -> CODELENS -> LEN_ 71 LEN_ -> LEN 72 Read deflate codes in fixed or dynamic block: 73 LEN -> LENEXT or LIT or TYPE 74 LENEXT -> DIST -> DISTEXT -> MATCH -> LEN 75 LIT -> LEN 76 Process trailer: 77 CHECK -> LENGTH -> DONE 78 */ 79 80/* state maintained between inflate() calls. Approximately 10K bytes. */ 81struct inflate_state { 82 inflate_mode mode; /* current inflate mode */ 83 int last; /* true if processing last block */ 84 int wrap; /* bit 0 true for zlib, bit 1 true for gzip */ 85 int havedict; /* true if dictionary provided */ 86 int flags; /* gzip header method and flags (0 if zlib) */ 87 unsigned dmax; /* zlib header max distance (INFLATE_STRICT) */ 88 unsigned long check; /* protected copy of check value */ 89 unsigned long total; /* protected copy of output count */ 90 gz_headerp head; /* where to save gzip header information */ 91 /* sliding window */ 92 unsigned wbits; /* log base 2 of requested window size */ 93 unsigned wsize; /* window size or zero if not using window */ 94 unsigned whave; /* valid bytes in the window */ 95 unsigned wnext; /* window write index */ 96 unsigned char FAR *window; /* allocated sliding window, if needed */ 97 /* bit accumulator */ 98 unsigned long hold; /* input bit accumulator */ 99 unsigned bits; /* number of bits in "in" */ 100 /* for string and stored block copying */ 101 unsigned length; /* literal or length of data to copy */ 102 unsigned offset; /* distance back to copy string from */ 103 /* for table and code decoding */ 104 unsigned extra; /* extra bits needed */ 105 /* fixed and dynamic code tables */ 106 code const FAR *lencode; /* starting table for length/literal codes */ 107 code const FAR *distcode; /* starting table for distance codes */ 108 unsigned lenbits; /* index bits for lencode */ 109 unsigned distbits; /* index bits for distcode */ 110 /* dynamic table building */ 111 unsigned ncode; /* number of code length code lengths */ 112 unsigned nlen; /* number of length code lengths */ 113 unsigned ndist; /* number of distance code lengths */ 114 unsigned have; /* number of code lengths in lens[] */ 115 code FAR *next; /* next available space in codes[] */ 116 unsigned short lens[320]; /* temporary storage for code lengths */ 117 unsigned short work[288]; /* work area for code table building */ 118 code codes[ENOUGH]; /* space for code tables */ 119 int sane; /* if false, allow invalid distance too far */ 120 int back; /* bits back of last unprocessed length/lit */ 121 unsigned was; /* initial length of match */ 122}; 123