1*10465441SEvalZero /* inflate.h -- internal inflate state definition 2*10465441SEvalZero * Copyright (C) 1995-2004 Mark Adler 3*10465441SEvalZero * For conditions of distribution and use, see copyright notice in zlib.h 4*10465441SEvalZero */ 5*10465441SEvalZero 6*10465441SEvalZero /* WARNING: this file should *not* be used by applications. It is 7*10465441SEvalZero part of the implementation of the compression library and is 8*10465441SEvalZero subject to change. Applications should only use zlib.h. 9*10465441SEvalZero */ 10*10465441SEvalZero 11*10465441SEvalZero /* define NO_GZIP when compiling if you want to disable gzip header and 12*10465441SEvalZero trailer decoding by inflate(). NO_GZIP would be used to avoid linking in 13*10465441SEvalZero the crc code when it is not needed. For shared libraries, gzip decoding 14*10465441SEvalZero should be left enabled. */ 15*10465441SEvalZero #ifndef NO_GZIP 16*10465441SEvalZero # define GUNZIP 17*10465441SEvalZero #endif 18*10465441SEvalZero 19*10465441SEvalZero /* Possible inflate modes between inflate() calls */ 20*10465441SEvalZero typedef enum { 21*10465441SEvalZero HEAD, /* i: waiting for magic header */ 22*10465441SEvalZero FLAGS, /* i: waiting for method and flags (gzip) */ 23*10465441SEvalZero TIME, /* i: waiting for modification time (gzip) */ 24*10465441SEvalZero OS, /* i: waiting for extra flags and operating system (gzip) */ 25*10465441SEvalZero EXLEN, /* i: waiting for extra length (gzip) */ 26*10465441SEvalZero EXTRA, /* i: waiting for extra bytes (gzip) */ 27*10465441SEvalZero NAME, /* i: waiting for end of file name (gzip) */ 28*10465441SEvalZero COMMENT, /* i: waiting for end of comment (gzip) */ 29*10465441SEvalZero HCRC, /* i: waiting for header crc (gzip) */ 30*10465441SEvalZero DICTID, /* i: waiting for dictionary check value */ 31*10465441SEvalZero DICT, /* waiting for inflateSetDictionary() call */ 32*10465441SEvalZero TYPE, /* i: waiting for type bits, including last-flag bit */ 33*10465441SEvalZero TYPEDO, /* i: same, but skip check to exit inflate on new block */ 34*10465441SEvalZero STORED, /* i: waiting for stored size (length and complement) */ 35*10465441SEvalZero COPY, /* i/o: waiting for input or output to copy stored block */ 36*10465441SEvalZero TABLE, /* i: waiting for dynamic block table lengths */ 37*10465441SEvalZero LENLENS, /* i: waiting for code length code lengths */ 38*10465441SEvalZero CODELENS, /* i: waiting for length/lit and distance code lengths */ 39*10465441SEvalZero LEN, /* i: waiting for length/lit code */ 40*10465441SEvalZero LENEXT, /* i: waiting for length extra bits */ 41*10465441SEvalZero DIST, /* i: waiting for distance code */ 42*10465441SEvalZero DISTEXT, /* i: waiting for distance extra bits */ 43*10465441SEvalZero MATCH, /* o: waiting for output space to copy string */ 44*10465441SEvalZero LIT, /* o: waiting for output space to write literal */ 45*10465441SEvalZero CHECK, /* i: waiting for 32-bit check value */ 46*10465441SEvalZero LENGTH, /* i: waiting for 32-bit length (gzip) */ 47*10465441SEvalZero DONE, /* finished check, done -- remain here until reset */ 48*10465441SEvalZero BAD, /* got a data error -- remain here until reset */ 49*10465441SEvalZero MEM, /* got an inflate() memory error -- remain here until reset */ 50*10465441SEvalZero SYNC /* looking for synchronization bytes to restart inflate() */ 51*10465441SEvalZero } inflate_mode; 52*10465441SEvalZero 53*10465441SEvalZero /* 54*10465441SEvalZero State transitions between above modes - 55*10465441SEvalZero 56*10465441SEvalZero (most modes can go to the BAD or MEM mode -- not shown for clarity) 57*10465441SEvalZero 58*10465441SEvalZero Process header: 59*10465441SEvalZero HEAD -> (gzip) or (zlib) 60*10465441SEvalZero (gzip) -> FLAGS -> TIME -> OS -> EXLEN -> EXTRA -> NAME 61*10465441SEvalZero NAME -> COMMENT -> HCRC -> TYPE 62*10465441SEvalZero (zlib) -> DICTID or TYPE 63*10465441SEvalZero DICTID -> DICT -> TYPE 64*10465441SEvalZero Read deflate blocks: 65*10465441SEvalZero TYPE -> STORED or TABLE or LEN or CHECK 66*10465441SEvalZero STORED -> COPY -> TYPE 67*10465441SEvalZero TABLE -> LENLENS -> CODELENS -> LEN 68*10465441SEvalZero Read deflate codes: 69*10465441SEvalZero LEN -> LENEXT or LIT or TYPE 70*10465441SEvalZero LENEXT -> DIST -> DISTEXT -> MATCH -> LEN 71*10465441SEvalZero LIT -> LEN 72*10465441SEvalZero Process trailer: 73*10465441SEvalZero CHECK -> LENGTH -> DONE 74*10465441SEvalZero */ 75*10465441SEvalZero 76*10465441SEvalZero /* state maintained between inflate() calls. Approximately 7K bytes. */ 77*10465441SEvalZero struct inflate_state { 78*10465441SEvalZero inflate_mode mode; /* current inflate mode */ 79*10465441SEvalZero int last; /* true if processing last block */ 80*10465441SEvalZero int wrap; /* bit 0 true for zlib, bit 1 true for gzip */ 81*10465441SEvalZero int havedict; /* true if dictionary provided */ 82*10465441SEvalZero int flags; /* gzip header method and flags (0 if zlib) */ 83*10465441SEvalZero unsigned dmax; /* zlib header max distance (INFLATE_STRICT) */ 84*10465441SEvalZero unsigned long check; /* protected copy of check value */ 85*10465441SEvalZero unsigned long total; /* protected copy of output count */ 86*10465441SEvalZero gz_headerp head; /* where to save gzip header information */ 87*10465441SEvalZero /* sliding window */ 88*10465441SEvalZero unsigned wbits; /* log base 2 of requested window size */ 89*10465441SEvalZero unsigned wsize; /* window size or zero if not using window */ 90*10465441SEvalZero unsigned whave; /* valid bytes in the window */ 91*10465441SEvalZero unsigned write; /* window write index */ 92*10465441SEvalZero unsigned char FAR *window; /* allocated sliding window, if needed */ 93*10465441SEvalZero /* bit accumulator */ 94*10465441SEvalZero unsigned long hold; /* input bit accumulator */ 95*10465441SEvalZero unsigned bits; /* number of bits in "in" */ 96*10465441SEvalZero /* for string and stored block copying */ 97*10465441SEvalZero unsigned length; /* literal or length of data to copy */ 98*10465441SEvalZero unsigned offset; /* distance back to copy string from */ 99*10465441SEvalZero /* for table and code decoding */ 100*10465441SEvalZero unsigned extra; /* extra bits needed */ 101*10465441SEvalZero /* fixed and dynamic code tables */ 102*10465441SEvalZero code const FAR *lencode; /* starting table for length/literal codes */ 103*10465441SEvalZero code const FAR *distcode; /* starting table for distance codes */ 104*10465441SEvalZero unsigned lenbits; /* index bits for lencode */ 105*10465441SEvalZero unsigned distbits; /* index bits for distcode */ 106*10465441SEvalZero /* dynamic table building */ 107*10465441SEvalZero unsigned ncode; /* number of code length code lengths */ 108*10465441SEvalZero unsigned nlen; /* number of length code lengths */ 109*10465441SEvalZero unsigned ndist; /* number of distance code lengths */ 110*10465441SEvalZero unsigned have; /* number of code lengths in lens[] */ 111*10465441SEvalZero code FAR *next; /* next available space in codes[] */ 112*10465441SEvalZero unsigned short lens[320]; /* temporary storage for code lengths */ 113*10465441SEvalZero unsigned short work[288]; /* work area for code table building */ 114*10465441SEvalZero code codes[ENOUGH]; /* space for code tables */ 115*10465441SEvalZero }; 116