1 /* inflate.h -- internal inflate state definition 2 * Copyright (C) 1995-2004 Mark Adler 3 * For conditions of distribution and use, see copyright notice in zlib.h 4 */ 5 6 #pragma ident "%Z%%M% %I% %E% SMI" 7 8 /* WARNING: this file should *not* be used by applications. It is 9 part of the implementation of the compression library and is 10 subject to change. Applications should only use zlib.h. 11 */ 12 13 /* define NO_GZIP when compiling if you want to disable gzip header and 14 trailer decoding by inflate(). NO_GZIP would be used to avoid linking in 15 the crc code when it is not needed. For shared libraries, gzip decoding 16 should be left enabled. */ 17 #ifndef NO_GZIP 18 # define GUNZIP 19 #endif 20 21 /* Possible inflate modes between inflate() calls */ 22 typedef enum { 23 HEAD, /* i: waiting for magic header */ 24 FLAGS, /* i: waiting for method and flags (gzip) */ 25 TIME, /* i: waiting for modification time (gzip) */ 26 OS, /* i: waiting for extra flags and operating system (gzip) */ 27 EXLEN, /* i: waiting for extra length (gzip) */ 28 EXTRA, /* i: waiting for extra bytes (gzip) */ 29 NAME, /* i: waiting for end of file name (gzip) */ 30 COMMENT, /* i: waiting for end of comment (gzip) */ 31 HCRC, /* i: waiting for header crc (gzip) */ 32 DICTID, /* i: waiting for dictionary check value */ 33 DICT, /* waiting for inflateSetDictionary() call */ 34 TYPE, /* i: waiting for type bits, including last-flag bit */ 35 TYPEDO, /* i: same, but skip check to exit inflate on new block */ 36 STORED, /* i: waiting for stored size (length and complement) */ 37 COPY, /* i/o: waiting for input or output to copy stored block */ 38 TABLE, /* i: waiting for dynamic block table lengths */ 39 LENLENS, /* i: waiting for code length code lengths */ 40 CODELENS, /* i: waiting for length/lit and distance code lengths */ 41 LEN, /* i: waiting for length/lit code */ 42 LENEXT, /* i: waiting for length extra bits */ 43 DIST, /* i: waiting for distance code */ 44 DISTEXT, /* i: waiting for distance extra bits */ 45 MATCH, /* o: waiting for output space to copy string */ 46 LIT, /* o: waiting for output space to write literal */ 47 CHECK, /* i: waiting for 32-bit check value */ 48 LENGTH, /* i: waiting for 32-bit length (gzip) */ 49 DONE, /* finished check, done -- remain here until reset */ 50 BAD, /* got a data error -- remain here until reset */ 51 MEM, /* got an inflate() memory error -- remain here until reset */ 52 SYNC /* looking for synchronization bytes to restart inflate() */ 53 } inflate_mode; 54 55 /* 56 State transitions between above modes - 57 58 (most modes can go to the BAD or MEM mode -- not shown for clarity) 59 60 Process header: 61 HEAD -> (gzip) or (zlib) 62 (gzip) -> FLAGS -> TIME -> OS -> EXLEN -> EXTRA -> NAME 63 NAME -> COMMENT -> HCRC -> TYPE 64 (zlib) -> DICTID or TYPE 65 DICTID -> DICT -> TYPE 66 Read deflate blocks: 67 TYPE -> STORED or TABLE or LEN or CHECK 68 STORED -> COPY -> TYPE 69 TABLE -> LENLENS -> CODELENS -> LEN 70 Read deflate codes: 71 LEN -> LENEXT or LIT or TYPE 72 LENEXT -> DIST -> DISTEXT -> MATCH -> LEN 73 LIT -> LEN 74 Process trailer: 75 CHECK -> LENGTH -> DONE 76 */ 77 78 /* state maintained between inflate() calls. Approximately 7K bytes. */ 79 struct inflate_state { 80 inflate_mode mode; /* current inflate mode */ 81 int last; /* true if processing last block */ 82 int wrap; /* bit 0 true for zlib, bit 1 true for gzip */ 83 int havedict; /* true if dictionary provided */ 84 int flags; /* gzip header method and flags (0 if zlib) */ 85 unsigned dmax; /* zlib header max distance (INFLATE_STRICT) */ 86 unsigned long check; /* protected copy of check value */ 87 unsigned long total; /* protected copy of output count */ 88 gz_headerp head; /* where to save gzip header information */ 89 /* sliding window */ 90 unsigned wbits; /* log base 2 of requested window size */ 91 unsigned wsize; /* window size or zero if not using window */ 92 unsigned whave; /* valid bytes in the window */ 93 unsigned write; /* window write index */ 94 unsigned char FAR *window; /* allocated sliding window, if needed */ 95 /* bit accumulator */ 96 unsigned long hold; /* input bit accumulator */ 97 unsigned bits; /* number of bits in "in" */ 98 /* for string and stored block copying */ 99 unsigned length; /* literal or length of data to copy */ 100 unsigned offset; /* distance back to copy string from */ 101 /* for table and code decoding */ 102 unsigned extra; /* extra bits needed */ 103 /* fixed and dynamic code tables */ 104 code const FAR *lencode; /* starting table for length/literal codes */ 105 code const FAR *distcode; /* starting table for distance codes */ 106 unsigned lenbits; /* index bits for lencode */ 107 unsigned distbits; /* index bits for distcode */ 108 /* dynamic table building */ 109 unsigned ncode; /* number of code length code lengths */ 110 unsigned nlen; /* number of length code lengths */ 111 unsigned ndist; /* number of distance code lengths */ 112 unsigned have; /* number of code lengths in lens[] */ 113 code FAR *next; /* next available space in codes[] */ 114 unsigned short lens[320]; /* temporary storage for code lengths */ 115 unsigned short work[288]; /* work area for code table building */ 116 code codes[ENOUGH]; /* space for code tables */ 117 }; 118