1b8382935SToomas Soome /* inflate.h -- internal inflate state definition 2*148fd93eSToomas Soome * Copyright (C) 1995-2019 Mark Adler 3b8382935SToomas Soome * For conditions of distribution and use, see copyright notice in zlib.h 4b8382935SToomas Soome */ 5b8382935SToomas Soome 6b8382935SToomas Soome /* WARNING: this file should *not* be used by applications. It is 7b8382935SToomas Soome part of the implementation of the compression library and is 8b8382935SToomas Soome subject to change. Applications should only use zlib.h. 9b8382935SToomas Soome */ 10b8382935SToomas Soome 11b8382935SToomas Soome /* define NO_GZIP when compiling if you want to disable gzip header and 12b8382935SToomas Soome trailer decoding by inflate(). NO_GZIP would be used to avoid linking in 13b8382935SToomas Soome the crc code when it is not needed. For shared libraries, gzip decoding 14b8382935SToomas Soome should be left enabled. */ 15b8382935SToomas Soome #ifndef NO_GZIP 16b8382935SToomas Soome # define GUNZIP 17b8382935SToomas Soome #endif 18b8382935SToomas Soome 19b8382935SToomas Soome /* Possible inflate modes between inflate() calls */ 20b8382935SToomas Soome typedef enum { 21b8382935SToomas Soome HEAD = 16180, /* i: waiting for magic header */ 22b8382935SToomas Soome FLAGS, /* i: waiting for method and flags (gzip) */ 23b8382935SToomas Soome TIME, /* i: waiting for modification time (gzip) */ 24b8382935SToomas Soome OS, /* i: waiting for extra flags and operating system (gzip) */ 25b8382935SToomas Soome EXLEN, /* i: waiting for extra length (gzip) */ 26b8382935SToomas Soome EXTRA, /* i: waiting for extra bytes (gzip) */ 27b8382935SToomas Soome NAME, /* i: waiting for end of file name (gzip) */ 28b8382935SToomas Soome COMMENT, /* i: waiting for end of comment (gzip) */ 29b8382935SToomas Soome HCRC, /* i: waiting for header crc (gzip) */ 30b8382935SToomas Soome DICTID, /* i: waiting for dictionary check value */ 31b8382935SToomas Soome DICT, /* waiting for inflateSetDictionary() call */ 32b8382935SToomas Soome TYPE, /* i: waiting for type bits, including last-flag bit */ 33b8382935SToomas Soome TYPEDO, /* i: same, but skip check to exit inflate on new block */ 34b8382935SToomas Soome STORED, /* i: waiting for stored size (length and complement) */ 35b8382935SToomas Soome COPY_, /* i/o: same as COPY below, but only first time in */ 36b8382935SToomas Soome COPY, /* i/o: waiting for input or output to copy stored block */ 37b8382935SToomas Soome TABLE, /* i: waiting for dynamic block table lengths */ 38b8382935SToomas Soome LENLENS, /* i: waiting for code length code lengths */ 39b8382935SToomas Soome CODELENS, /* i: waiting for length/lit and distance code lengths */ 40b8382935SToomas Soome LEN_, /* i: same as LEN below, but only first time in */ 41b8382935SToomas Soome LEN, /* i: waiting for length/lit/eob code */ 42b8382935SToomas Soome LENEXT, /* i: waiting for length extra bits */ 43b8382935SToomas Soome DIST, /* i: waiting for distance code */ 44b8382935SToomas Soome DISTEXT, /* i: waiting for distance extra bits */ 45b8382935SToomas Soome MATCH, /* o: waiting for output space to copy string */ 46b8382935SToomas Soome LIT, /* o: waiting for output space to write literal */ 47b8382935SToomas Soome CHECK, /* i: waiting for 32-bit check value */ 48b8382935SToomas Soome LENGTH, /* i: waiting for 32-bit length (gzip) */ 49b8382935SToomas Soome DONE, /* finished check, done -- remain here until reset */ 50b8382935SToomas Soome BAD, /* got a data error -- remain here until reset */ 51b8382935SToomas Soome MEM, /* got an inflate() memory error -- remain here until reset */ 52b8382935SToomas Soome SYNC /* looking for synchronization bytes to restart inflate() */ 53b8382935SToomas Soome } inflate_mode; 54b8382935SToomas Soome 55b8382935SToomas Soome /* 56b8382935SToomas Soome State transitions between above modes - 57b8382935SToomas Soome 58b8382935SToomas Soome (most modes can go to BAD or MEM on error -- not shown for clarity) 59b8382935SToomas Soome 60b8382935SToomas Soome Process header: 61b8382935SToomas Soome HEAD -> (gzip) or (zlib) or (raw) 62b8382935SToomas Soome (gzip) -> FLAGS -> TIME -> OS -> EXLEN -> EXTRA -> NAME -> COMMENT -> 63b8382935SToomas Soome HCRC -> TYPE 64b8382935SToomas Soome (zlib) -> DICTID or TYPE 65b8382935SToomas Soome DICTID -> DICT -> TYPE 66b8382935SToomas Soome (raw) -> TYPEDO 67b8382935SToomas Soome Read deflate blocks: 68b8382935SToomas Soome TYPE -> TYPEDO -> STORED or TABLE or LEN_ or CHECK 69b8382935SToomas Soome STORED -> COPY_ -> COPY -> TYPE 70b8382935SToomas Soome TABLE -> LENLENS -> CODELENS -> LEN_ 71b8382935SToomas Soome LEN_ -> LEN 72b8382935SToomas Soome Read deflate codes in fixed or dynamic block: 73b8382935SToomas Soome LEN -> LENEXT or LIT or TYPE 74b8382935SToomas Soome LENEXT -> DIST -> DISTEXT -> MATCH -> LEN 75b8382935SToomas Soome LIT -> LEN 76b8382935SToomas Soome Process trailer: 77b8382935SToomas Soome CHECK -> LENGTH -> DONE 78b8382935SToomas Soome */ 79b8382935SToomas Soome 80b8382935SToomas Soome /* State maintained between inflate() calls -- approximately 7K bytes, not 81b8382935SToomas Soome including the allocated sliding window, which is up to 32K bytes. */ 82b8382935SToomas Soome struct inflate_state { 83b8382935SToomas Soome z_streamp strm; /* pointer back to this zlib stream */ 84b8382935SToomas Soome inflate_mode mode; /* current inflate mode */ 85b8382935SToomas Soome int last; /* true if processing last block */ 86b8382935SToomas Soome int wrap; /* bit 0 true for zlib, bit 1 true for gzip, 87b8382935SToomas Soome bit 2 true to validate check value */ 88b8382935SToomas Soome int havedict; /* true if dictionary provided */ 89*148fd93eSToomas Soome int flags; /* gzip header method and flags, 0 if zlib, or 90*148fd93eSToomas Soome -1 if raw or no header yet */ 91b8382935SToomas Soome unsigned dmax; /* zlib header max distance (INFLATE_STRICT) */ 92b8382935SToomas Soome unsigned long check; /* protected copy of check value */ 93b8382935SToomas Soome unsigned long total; /* protected copy of output count */ 94b8382935SToomas Soome gz_headerp head; /* where to save gzip header information */ 95b8382935SToomas Soome /* sliding window */ 96b8382935SToomas Soome unsigned wbits; /* log base 2 of requested window size */ 97b8382935SToomas Soome unsigned wsize; /* window size or zero if not using window */ 98b8382935SToomas Soome unsigned whave; /* valid bytes in the window */ 99b8382935SToomas Soome unsigned wnext; /* window write index */ 100b8382935SToomas Soome unsigned char FAR *window; /* allocated sliding window, if needed */ 101b8382935SToomas Soome /* bit accumulator */ 102b8382935SToomas Soome unsigned long hold; /* input bit accumulator */ 103b8382935SToomas Soome unsigned bits; /* number of bits in "in" */ 104b8382935SToomas Soome /* for string and stored block copying */ 105b8382935SToomas Soome unsigned length; /* literal or length of data to copy */ 106b8382935SToomas Soome unsigned offset; /* distance back to copy string from */ 107b8382935SToomas Soome /* for table and code decoding */ 108b8382935SToomas Soome unsigned extra; /* extra bits needed */ 109b8382935SToomas Soome /* fixed and dynamic code tables */ 110b8382935SToomas Soome code const FAR *lencode; /* starting table for length/literal codes */ 111b8382935SToomas Soome code const FAR *distcode; /* starting table for distance codes */ 112b8382935SToomas Soome unsigned lenbits; /* index bits for lencode */ 113b8382935SToomas Soome unsigned distbits; /* index bits for distcode */ 114b8382935SToomas Soome /* dynamic table building */ 115b8382935SToomas Soome unsigned ncode; /* number of code length code lengths */ 116b8382935SToomas Soome unsigned nlen; /* number of length code lengths */ 117b8382935SToomas Soome unsigned ndist; /* number of distance code lengths */ 118b8382935SToomas Soome unsigned have; /* number of code lengths in lens[] */ 119b8382935SToomas Soome code FAR *next; /* next available space in codes[] */ 120b8382935SToomas Soome unsigned short lens[320]; /* temporary storage for code lengths */ 121b8382935SToomas Soome unsigned short work[288]; /* work area for code table building */ 122b8382935SToomas Soome code codes[ENOUGH]; /* space for code tables */ 123b8382935SToomas Soome int sane; /* if false, allow invalid distance too far */ 124b8382935SToomas Soome int back; /* bits back of last unprocessed length/lit */ 125b8382935SToomas Soome unsigned was; /* initial length of match */ 126b8382935SToomas Soome }; 127