inflate.h revision 157044
11297Salm/* inflate.h -- internal inflate state definition 21297Salm * Copyright (C) 1995-2004 Mark Adler 31297Salm * For conditions of distribution and use, see copyright notice in zlib.h 41297Salm */ 51297Salm 61297Salm/* WARNING: this file should *not* be used by applications. It is 71297Salm part of the implementation of the compression library and is 81297Salm subject to change. Applications should only use zlib.h. 91297Salm */ 101297Salm 111297Salm/* define NO_GZIP when compiling if you want to disable gzip header and 121297Salm trailer decoding by inflate(). NO_GZIP would be used to avoid linking in 131297Salm the crc code when it is not needed. For shared libraries, gzip decoding 141297Salm should be left enabled. */ 151297Salm#ifndef NO_GZIP 161297Salm# define GUNZIP 171297Salm#endif 181297Salm 191297Salm/* Possible inflate modes between inflate() calls */ 201297Salmtypedef enum { 211297Salm HEAD, /* i: waiting for magic header */ 221297Salm FLAGS, /* i: waiting for method and flags (gzip) */ 231297Salm TIME, /* i: waiting for modification time (gzip) */ 241297Salm OS, /* i: waiting for extra flags and operating system (gzip) */ 251297Salm EXLEN, /* i: waiting for extra length (gzip) */ 261297Salm EXTRA, /* i: waiting for extra bytes (gzip) */ 271297Salm NAME, /* i: waiting for end of file name (gzip) */ 281297Salm COMMENT, /* i: waiting for end of comment (gzip) */ 291297Salm HCRC, /* i: waiting for header crc (gzip) */ 301297Salm DICTID, /* i: waiting for dictionary check value */ 311297Salm DICT, /* waiting for inflateSetDictionary() call */ 321297Salm TYPE, /* i: waiting for type bits, including last-flag bit */ 331297Salm TYPEDO, /* i: same, but skip check to exit inflate on new block */ 341297Salm STORED, /* i: waiting for stored size (length and complement) */ 351297Salm COPY, /* i/o: waiting for input or output to copy stored block */ 361297Salm TABLE, /* i: waiting for dynamic block table lengths */ 371297Salm LENLENS, /* i: waiting for code length code lengths */ 381297Salm CODELENS, /* i: waiting for length/lit and distance code lengths */ 391297Salm LEN, /* i: waiting for length/lit code */ 401297Salm LENEXT, /* i: waiting for length extra bits */ 411297Salm DIST, /* i: waiting for distance code */ 421297Salm DISTEXT, /* i: waiting for distance extra bits */ 431297Salm MATCH, /* o: waiting for output space to copy string */ 441297Salm LIT, /* o: waiting for output space to write literal */ 451297Salm CHECK, /* i: waiting for 32-bit check value */ 461297Salm LENGTH, /* i: waiting for 32-bit length (gzip) */ 471297Salm DONE, /* finished check, done -- remain here until reset */ 481297Salm BAD, /* got a data error -- remain here until reset */ 491297Salm MEM, /* got an inflate() memory error -- remain here until reset */ 501297Salm SYNC /* looking for synchronization bytes to restart inflate() */ 511297Salm} inflate_mode; 521297Salm 531297Salm/* 541297Salm State transitions between above modes - 551297Salm 561297Salm (most modes can go to the BAD or MEM mode -- not shown for clarity) 571297Salm 581297Salm Process header: 591297Salm HEAD -> (gzip) or (zlib) 601297Salm (gzip) -> FLAGS -> TIME -> OS -> EXLEN -> EXTRA -> NAME 611297Salm NAME -> COMMENT -> HCRC -> TYPE 621297Salm (zlib) -> DICTID or TYPE 631297Salm DICTID -> DICT -> TYPE 641297Salm Read deflate blocks: 651297Salm TYPE -> STORED or TABLE or LEN or CHECK 661297Salm STORED -> COPY -> TYPE 671297Salm TABLE -> LENLENS -> CODELENS -> LEN 681297Salm Read deflate codes: 691297Salm LEN -> LENEXT or LIT or TYPE 701297Salm LENEXT -> DIST -> DISTEXT -> MATCH -> LEN 711297Salm LIT -> LEN 721297Salm Process trailer: 731297Salm CHECK -> LENGTH -> DONE 741297Salm */ 751297Salm 761297Salm/* state maintained between inflate() calls. Approximately 7K bytes. */ 771297Salmstruct inflate_state { 781297Salm inflate_mode mode; /* current inflate mode */ 791297Salm int last; /* true if processing last block */ 801297Salm int wrap; /* bit 0 true for zlib, bit 1 true for gzip */ 811297Salm int havedict; /* true if dictionary provided */ 821297Salm int flags; /* gzip header method and flags (0 if zlib) */ 831297Salm unsigned dmax; /* zlib header max distance (INFLATE_STRICT) */ 841297Salm unsigned long check; /* protected copy of check value */ 851297Salm unsigned long total; /* protected copy of output count */ 861297Salm gz_headerp head; /* where to save gzip header information */ 871297Salm /* sliding window */ 881297Salm unsigned wbits; /* log base 2 of requested window size */ 891297Salm unsigned wsize; /* window size or zero if not using window */ 901297Salm unsigned whave; /* valid bytes in the window */ 911297Salm unsigned write; /* window write index */ 921297Salm unsigned char FAR *window; /* allocated sliding window, if needed */ 931297Salm /* bit accumulator */ 941297Salm unsigned long hold; /* input bit accumulator */ 951297Salm unsigned bits; /* number of bits in "in" */ 961297Salm /* for string and stored block copying */ 971297Salm unsigned length; /* literal or length of data to copy */ 981297Salm unsigned offset; /* distance back to copy string from */ 991297Salm /* for table and code decoding */ 1001297Salm unsigned extra; /* extra bits needed */ 1011297Salm /* fixed and dynamic code tables */ 1021297Salm code const FAR *lencode; /* starting table for length/literal codes */ 1031297Salm code const FAR *distcode; /* starting table for distance codes */ 1041297Salm unsigned lenbits; /* index bits for lencode */ 1051297Salm unsigned distbits; /* index bits for distcode */ 1061297Salm /* dynamic table building */ 1071297Salm unsigned ncode; /* number of code length code lengths */ 1081297Salm unsigned nlen; /* number of length code lengths */ 1091297Salm unsigned ndist; /* number of distance code lengths */ 1101297Salm unsigned have; /* number of code lengths in lens[] */ 1111297Salm code FAR *next; /* next available space in codes[] */ 1121297Salm unsigned short lens[320]; /* temporary storage for code lengths */ 1131297Salm unsigned short work[288]; /* work area for code table building */ 1141297Salm code codes[ENOUGH]; /* space for code tables */ 1151297Salm}; 1161297Salm