1c9083b85SXin LI /* inflate.h -- internal inflate state definition 2*cd882207SXin LI * Copyright (C) 1995-2019 Mark Adler 3c9083b85SXin LI * For conditions of distribution and use, see copyright notice in zlib.h 4c9083b85SXin LI */ 5c9083b85SXin LI 6c9083b85SXin LI /* WARNING: this file should *not* be used by applications. It is 7c9083b85SXin LI part of the implementation of the compression library and is 8c9083b85SXin LI subject to change. Applications should only use zlib.h. 9c9083b85SXin LI */ 10c9083b85SXin LI 11c9083b85SXin LI /* define NO_GZIP when compiling if you want to disable gzip header and 12c9083b85SXin LI trailer decoding by inflate(). NO_GZIP would be used to avoid linking in 13c9083b85SXin LI the crc code when it is not needed. For shared libraries, gzip decoding 14c9083b85SXin LI should be left enabled. */ 15c9083b85SXin LI #ifndef NO_GZIP 16c9083b85SXin LI # define GUNZIP 17c9083b85SXin LI #endif 18c9083b85SXin LI 19c9083b85SXin LI /* Possible inflate modes between inflate() calls */ 20c9083b85SXin LI typedef enum { 21c9083b85SXin LI HEAD = 16180, /* i: waiting for magic header */ 22c9083b85SXin LI FLAGS, /* i: waiting for method and flags (gzip) */ 23c9083b85SXin LI TIME, /* i: waiting for modification time (gzip) */ 24c9083b85SXin LI OS, /* i: waiting for extra flags and operating system (gzip) */ 25c9083b85SXin LI EXLEN, /* i: waiting for extra length (gzip) */ 26c9083b85SXin LI EXTRA, /* i: waiting for extra bytes (gzip) */ 27c9083b85SXin LI NAME, /* i: waiting for end of file name (gzip) */ 28c9083b85SXin LI COMMENT, /* i: waiting for end of comment (gzip) */ 29c9083b85SXin LI HCRC, /* i: waiting for header crc (gzip) */ 30c9083b85SXin LI DICTID, /* i: waiting for dictionary check value */ 31c9083b85SXin LI DICT, /* waiting for inflateSetDictionary() call */ 32c9083b85SXin LI TYPE, /* i: waiting for type bits, including last-flag bit */ 33c9083b85SXin LI TYPEDO, /* i: same, but skip check to exit inflate on new block */ 34c9083b85SXin LI STORED, /* i: waiting for stored size (length and complement) */ 35c9083b85SXin LI COPY_, /* i/o: same as COPY below, but only first time in */ 36c9083b85SXin LI COPY, /* i/o: waiting for input or output to copy stored block */ 37c9083b85SXin LI TABLE, /* i: waiting for dynamic block table lengths */ 38c9083b85SXin LI LENLENS, /* i: waiting for code length code lengths */ 39c9083b85SXin LI CODELENS, /* i: waiting for length/lit and distance code lengths */ 40c9083b85SXin LI LEN_, /* i: same as LEN below, but only first time in */ 41c9083b85SXin LI LEN, /* i: waiting for length/lit/eob code */ 42c9083b85SXin LI LENEXT, /* i: waiting for length extra bits */ 43c9083b85SXin LI DIST, /* i: waiting for distance code */ 44c9083b85SXin LI DISTEXT, /* i: waiting for distance extra bits */ 45c9083b85SXin LI MATCH, /* o: waiting for output space to copy string */ 46c9083b85SXin LI LIT, /* o: waiting for output space to write literal */ 47c9083b85SXin LI CHECK, /* i: waiting for 32-bit check value */ 48c9083b85SXin LI LENGTH, /* i: waiting for 32-bit length (gzip) */ 49c9083b85SXin LI DONE, /* finished check, done -- remain here until reset */ 50c9083b85SXin LI BAD, /* got a data error -- remain here until reset */ 51c9083b85SXin LI MEM, /* got an inflate() memory error -- remain here until reset */ 52c9083b85SXin LI SYNC /* looking for synchronization bytes to restart inflate() */ 53c9083b85SXin LI } inflate_mode; 54c9083b85SXin LI 55c9083b85SXin LI /* 56c9083b85SXin LI State transitions between above modes - 57c9083b85SXin LI 58c9083b85SXin LI (most modes can go to BAD or MEM on error -- not shown for clarity) 59c9083b85SXin LI 60c9083b85SXin LI Process header: 61c9083b85SXin LI HEAD -> (gzip) or (zlib) or (raw) 62c9083b85SXin LI (gzip) -> FLAGS -> TIME -> OS -> EXLEN -> EXTRA -> NAME -> COMMENT -> 63c9083b85SXin LI HCRC -> TYPE 64c9083b85SXin LI (zlib) -> DICTID or TYPE 65c9083b85SXin LI DICTID -> DICT -> TYPE 66c9083b85SXin LI (raw) -> TYPEDO 67c9083b85SXin LI Read deflate blocks: 68c9083b85SXin LI TYPE -> TYPEDO -> STORED or TABLE or LEN_ or CHECK 69c9083b85SXin LI STORED -> COPY_ -> COPY -> TYPE 70c9083b85SXin LI TABLE -> LENLENS -> CODELENS -> LEN_ 71c9083b85SXin LI LEN_ -> LEN 72c9083b85SXin LI Read deflate codes in fixed or dynamic block: 73c9083b85SXin LI LEN -> LENEXT or LIT or TYPE 74c9083b85SXin LI LENEXT -> DIST -> DISTEXT -> MATCH -> LEN 75c9083b85SXin LI LIT -> LEN 76c9083b85SXin LI Process trailer: 77c9083b85SXin LI CHECK -> LENGTH -> DONE 78c9083b85SXin LI */ 79c9083b85SXin LI 80c9083b85SXin LI /* State maintained between inflate() calls -- approximately 7K bytes, not 81c9083b85SXin LI including the allocated sliding window, which is up to 32K bytes. */ 82c9083b85SXin LI struct inflate_state { 83c9083b85SXin LI z_streamp strm; /* pointer back to this zlib stream */ 84c9083b85SXin LI inflate_mode mode; /* current inflate mode */ 85c9083b85SXin LI int last; /* true if processing last block */ 86c9083b85SXin LI int wrap; /* bit 0 true for zlib, bit 1 true for gzip, 87c9083b85SXin LI bit 2 true to validate check value */ 88c9083b85SXin LI int havedict; /* true if dictionary provided */ 89*cd882207SXin LI int flags; /* gzip header method and flags, 0 if zlib, or 90*cd882207SXin LI -1 if raw or no header yet */ 91c9083b85SXin LI unsigned dmax; /* zlib header max distance (INFLATE_STRICT) */ 92c9083b85SXin LI unsigned long check; /* protected copy of check value */ 93c9083b85SXin LI unsigned long total; /* protected copy of output count */ 94c9083b85SXin LI gz_headerp head; /* where to save gzip header information */ 95c9083b85SXin LI /* sliding window */ 96c9083b85SXin LI unsigned wbits; /* log base 2 of requested window size */ 97c9083b85SXin LI unsigned wsize; /* window size or zero if not using window */ 98c9083b85SXin LI unsigned whave; /* valid bytes in the window */ 99c9083b85SXin LI unsigned wnext; /* window write index */ 100c9083b85SXin LI unsigned char FAR *window; /* allocated sliding window, if needed */ 101c9083b85SXin LI /* bit accumulator */ 102c9083b85SXin LI unsigned long hold; /* input bit accumulator */ 103c9083b85SXin LI unsigned bits; /* number of bits in "in" */ 104c9083b85SXin LI /* for string and stored block copying */ 105c9083b85SXin LI unsigned length; /* literal or length of data to copy */ 106c9083b85SXin LI unsigned offset; /* distance back to copy string from */ 107c9083b85SXin LI /* for table and code decoding */ 108c9083b85SXin LI unsigned extra; /* extra bits needed */ 109c9083b85SXin LI /* fixed and dynamic code tables */ 110c9083b85SXin LI code const FAR *lencode; /* starting table for length/literal codes */ 111c9083b85SXin LI code const FAR *distcode; /* starting table for distance codes */ 112c9083b85SXin LI unsigned lenbits; /* index bits for lencode */ 113c9083b85SXin LI unsigned distbits; /* index bits for distcode */ 114c9083b85SXin LI /* dynamic table building */ 115c9083b85SXin LI unsigned ncode; /* number of code length code lengths */ 116c9083b85SXin LI unsigned nlen; /* number of length code lengths */ 117c9083b85SXin LI unsigned ndist; /* number of distance code lengths */ 118c9083b85SXin LI unsigned have; /* number of code lengths in lens[] */ 119c9083b85SXin LI code FAR *next; /* next available space in codes[] */ 120c9083b85SXin LI unsigned short lens[320]; /* temporary storage for code lengths */ 121c9083b85SXin LI unsigned short work[288]; /* work area for code table building */ 122c9083b85SXin LI code codes[ENOUGH]; /* space for code tables */ 123c9083b85SXin LI int sane; /* if false, allow invalid distance too far */ 124c9083b85SXin LI int back; /* bits back of last unprocessed length/lit */ 125c9083b85SXin LI unsigned was; /* initial length of match */ 126c9083b85SXin LI }; 127