11e9a6b47SJoerg Sonnenberger /* inflate.h -- internal inflate state definition 2*e041647aSSascha Wildner * Copyright (C) 1995-2016 Mark Adler 31e9a6b47SJoerg Sonnenberger * For conditions of distribution and use, see copyright notice in zlib.h 41e9a6b47SJoerg Sonnenberger */ 51e9a6b47SJoerg Sonnenberger 61e9a6b47SJoerg Sonnenberger /* WARNING: this file should *not* be used by applications. It is 71e9a6b47SJoerg Sonnenberger part of the implementation of the compression library and is 81e9a6b47SJoerg Sonnenberger subject to change. Applications should only use zlib.h. 91e9a6b47SJoerg Sonnenberger */ 101e9a6b47SJoerg Sonnenberger 111e9a6b47SJoerg Sonnenberger /* define NO_GZIP when compiling if you want to disable gzip header and 121e9a6b47SJoerg Sonnenberger trailer decoding by inflate(). NO_GZIP would be used to avoid linking in 131e9a6b47SJoerg Sonnenberger the crc code when it is not needed. For shared libraries, gzip decoding 141e9a6b47SJoerg Sonnenberger should be left enabled. */ 151e9a6b47SJoerg Sonnenberger #ifndef NO_GZIP 161e9a6b47SJoerg Sonnenberger # define GUNZIP 171e9a6b47SJoerg Sonnenberger #endif 181e9a6b47SJoerg Sonnenberger 191e9a6b47SJoerg Sonnenberger /* Possible inflate modes between inflate() calls */ 201e9a6b47SJoerg Sonnenberger typedef enum { 21*e041647aSSascha Wildner HEAD = 16180, /* i: waiting for magic header */ 221e9a6b47SJoerg Sonnenberger FLAGS, /* i: waiting for method and flags (gzip) */ 231e9a6b47SJoerg Sonnenberger TIME, /* i: waiting for modification time (gzip) */ 241e9a6b47SJoerg Sonnenberger OS, /* i: waiting for extra flags and operating system (gzip) */ 251e9a6b47SJoerg Sonnenberger EXLEN, /* i: waiting for extra length (gzip) */ 261e9a6b47SJoerg Sonnenberger EXTRA, /* i: waiting for extra bytes (gzip) */ 271e9a6b47SJoerg Sonnenberger NAME, /* i: waiting for end of file name (gzip) */ 281e9a6b47SJoerg Sonnenberger COMMENT, /* i: waiting for end of comment (gzip) */ 291e9a6b47SJoerg Sonnenberger HCRC, /* i: waiting for header crc (gzip) */ 301e9a6b47SJoerg Sonnenberger DICTID, /* i: waiting for dictionary check value */ 311e9a6b47SJoerg Sonnenberger DICT, /* waiting for inflateSetDictionary() call */ 321e9a6b47SJoerg Sonnenberger TYPE, /* i: waiting for type bits, including last-flag bit */ 331e9a6b47SJoerg Sonnenberger TYPEDO, /* i: same, but skip check to exit inflate on new block */ 341e9a6b47SJoerg Sonnenberger STORED, /* i: waiting for stored size (length and complement) */ 35fe927c51SPeter Avalos COPY_, /* i/o: same as COPY below, but only first time in */ 361e9a6b47SJoerg Sonnenberger COPY, /* i/o: waiting for input or output to copy stored block */ 371e9a6b47SJoerg Sonnenberger TABLE, /* i: waiting for dynamic block table lengths */ 381e9a6b47SJoerg Sonnenberger LENLENS, /* i: waiting for code length code lengths */ 391e9a6b47SJoerg Sonnenberger CODELENS, /* i: waiting for length/lit and distance code lengths */ 40fe927c51SPeter Avalos LEN_, /* i: same as LEN below, but only first time in */ 41fe927c51SPeter Avalos LEN, /* i: waiting for length/lit/eob code */ 421e9a6b47SJoerg Sonnenberger LENEXT, /* i: waiting for length extra bits */ 431e9a6b47SJoerg Sonnenberger DIST, /* i: waiting for distance code */ 441e9a6b47SJoerg Sonnenberger DISTEXT, /* i: waiting for distance extra bits */ 451e9a6b47SJoerg Sonnenberger MATCH, /* o: waiting for output space to copy string */ 461e9a6b47SJoerg Sonnenberger LIT, /* o: waiting for output space to write literal */ 471e9a6b47SJoerg Sonnenberger CHECK, /* i: waiting for 32-bit check value */ 481e9a6b47SJoerg Sonnenberger LENGTH, /* i: waiting for 32-bit length (gzip) */ 491e9a6b47SJoerg Sonnenberger DONE, /* finished check, done -- remain here until reset */ 501e9a6b47SJoerg Sonnenberger BAD, /* got a data error -- remain here until reset */ 511e9a6b47SJoerg Sonnenberger MEM, /* got an inflate() memory error -- remain here until reset */ 521e9a6b47SJoerg Sonnenberger SYNC /* looking for synchronization bytes to restart inflate() */ 531e9a6b47SJoerg Sonnenberger } inflate_mode; 541e9a6b47SJoerg Sonnenberger 551e9a6b47SJoerg Sonnenberger /* 561e9a6b47SJoerg Sonnenberger State transitions between above modes - 571e9a6b47SJoerg Sonnenberger 58fe927c51SPeter Avalos (most modes can go to BAD or MEM on error -- not shown for clarity) 591e9a6b47SJoerg Sonnenberger 601e9a6b47SJoerg Sonnenberger Process header: 61fe927c51SPeter Avalos HEAD -> (gzip) or (zlib) or (raw) 62fe927c51SPeter Avalos (gzip) -> FLAGS -> TIME -> OS -> EXLEN -> EXTRA -> NAME -> COMMENT -> 63fe927c51SPeter Avalos HCRC -> TYPE 641e9a6b47SJoerg Sonnenberger (zlib) -> DICTID or TYPE 651e9a6b47SJoerg Sonnenberger DICTID -> DICT -> TYPE 66fe927c51SPeter Avalos (raw) -> TYPEDO 671e9a6b47SJoerg Sonnenberger Read deflate blocks: 68fe927c51SPeter Avalos TYPE -> TYPEDO -> STORED or TABLE or LEN_ or CHECK 69fe927c51SPeter Avalos STORED -> COPY_ -> COPY -> TYPE 70fe927c51SPeter Avalos TABLE -> LENLENS -> CODELENS -> LEN_ 71fe927c51SPeter Avalos LEN_ -> LEN 72fe927c51SPeter Avalos Read deflate codes in fixed or dynamic block: 731e9a6b47SJoerg Sonnenberger LEN -> LENEXT or LIT or TYPE 741e9a6b47SJoerg Sonnenberger LENEXT -> DIST -> DISTEXT -> MATCH -> LEN 751e9a6b47SJoerg Sonnenberger LIT -> LEN 761e9a6b47SJoerg Sonnenberger Process trailer: 771e9a6b47SJoerg Sonnenberger CHECK -> LENGTH -> DONE 781e9a6b47SJoerg Sonnenberger */ 791e9a6b47SJoerg Sonnenberger 80*e041647aSSascha Wildner /* State maintained between inflate() calls -- approximately 7K bytes, not 81*e041647aSSascha Wildner including the allocated sliding window, which is up to 32K bytes. */ 821e9a6b47SJoerg Sonnenberger struct inflate_state { 83*e041647aSSascha Wildner z_streamp strm; /* pointer back to this zlib stream */ 841e9a6b47SJoerg Sonnenberger inflate_mode mode; /* current inflate mode */ 851e9a6b47SJoerg Sonnenberger int last; /* true if processing last block */ 86*e041647aSSascha Wildner int wrap; /* bit 0 true for zlib, bit 1 true for gzip, 87*e041647aSSascha Wildner bit 2 true to validate check value */ 881e9a6b47SJoerg Sonnenberger int havedict; /* true if dictionary provided */ 891e9a6b47SJoerg Sonnenberger int flags; /* gzip header method and flags (0 if zlib) */ 901e9a6b47SJoerg Sonnenberger unsigned dmax; /* zlib header max distance (INFLATE_STRICT) */ 911e9a6b47SJoerg Sonnenberger unsigned long check; /* protected copy of check value */ 921e9a6b47SJoerg Sonnenberger unsigned long total; /* protected copy of output count */ 931e9a6b47SJoerg Sonnenberger gz_headerp head; /* where to save gzip header information */ 941e9a6b47SJoerg Sonnenberger /* sliding window */ 951e9a6b47SJoerg Sonnenberger unsigned wbits; /* log base 2 of requested window size */ 961e9a6b47SJoerg Sonnenberger unsigned wsize; /* window size or zero if not using window */ 971e9a6b47SJoerg Sonnenberger unsigned whave; /* valid bytes in the window */ 98fe927c51SPeter Avalos unsigned wnext; /* window write index */ 991e9a6b47SJoerg Sonnenberger unsigned char FAR *window; /* allocated sliding window, if needed */ 1001e9a6b47SJoerg Sonnenberger /* bit accumulator */ 1011e9a6b47SJoerg Sonnenberger unsigned long hold; /* input bit accumulator */ 1021e9a6b47SJoerg Sonnenberger unsigned bits; /* number of bits in "in" */ 1031e9a6b47SJoerg Sonnenberger /* for string and stored block copying */ 1041e9a6b47SJoerg Sonnenberger unsigned length; /* literal or length of data to copy */ 1051e9a6b47SJoerg Sonnenberger unsigned offset; /* distance back to copy string from */ 1061e9a6b47SJoerg Sonnenberger /* for table and code decoding */ 1071e9a6b47SJoerg Sonnenberger unsigned extra; /* extra bits needed */ 1081e9a6b47SJoerg Sonnenberger /* fixed and dynamic code tables */ 1091e9a6b47SJoerg Sonnenberger code const FAR *lencode; /* starting table for length/literal codes */ 1101e9a6b47SJoerg Sonnenberger code const FAR *distcode; /* starting table for distance codes */ 1111e9a6b47SJoerg Sonnenberger unsigned lenbits; /* index bits for lencode */ 1121e9a6b47SJoerg Sonnenberger unsigned distbits; /* index bits for distcode */ 1131e9a6b47SJoerg Sonnenberger /* dynamic table building */ 1141e9a6b47SJoerg Sonnenberger unsigned ncode; /* number of code length code lengths */ 1151e9a6b47SJoerg Sonnenberger unsigned nlen; /* number of length code lengths */ 1161e9a6b47SJoerg Sonnenberger unsigned ndist; /* number of distance code lengths */ 1171e9a6b47SJoerg Sonnenberger unsigned have; /* number of code lengths in lens[] */ 1181e9a6b47SJoerg Sonnenberger code FAR *next; /* next available space in codes[] */ 1191e9a6b47SJoerg Sonnenberger unsigned short lens[320]; /* temporary storage for code lengths */ 1201e9a6b47SJoerg Sonnenberger unsigned short work[288]; /* work area for code table building */ 1211e9a6b47SJoerg Sonnenberger code codes[ENOUGH]; /* space for code tables */ 122fe927c51SPeter Avalos int sane; /* if false, allow invalid distance too far */ 123fe927c51SPeter Avalos int back; /* bits back of last unprocessed length/lit */ 124fe927c51SPeter Avalos unsigned was; /* initial length of match */ 1251e9a6b47SJoerg Sonnenberger }; 126