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 /* WARNING: this file should *not* be used by applications. It is 7 part of the implementation of the compression library and is 8 subject to change. Applications should only use zlib.h. 9 */ 10 11 #ifndef _INFLATE_H_ 12 #define _INFLATE_H_ 13 14 /* define NO_GZIP when compiling if you want to disable gzip header and 15 trailer decoding by inflate(). NO_GZIP would be used to avoid linking in 16 the crc code when it is not needed. For shared libraries, gzip decoding 17 should be left enabled. */ 18 #ifndef NO_GZIP 19 # define GUNZIP 20 #endif 21 22 /* Possible inflate modes between inflate() calls */ 23 typedef enum { 24 HEAD, /* i: waiting for magic header */ 25 FLAGS, /* i: waiting for method and flags (gzip) */ 26 TIME, /* i: waiting for modification time (gzip) */ 27 OS, /* i: waiting for extra flags and operating system (gzip) */ 28 EXLEN, /* i: waiting for extra length (gzip) */ 29 EXTRA, /* i: waiting for extra bytes (gzip) */ 30 NAME, /* i: waiting for end of file name (gzip) */ 31 COMMENT, /* i: waiting for end of comment (gzip) */ 32 HCRC, /* i: waiting for header crc (gzip) */ 33 DICTID, /* i: waiting for dictionary check value */ 34 DICT, /* waiting for inflateSetDictionary() call */ 35 TYPE, /* i: waiting for type bits, including last-flag bit */ 36 TYPEDO, /* i: same, but skip check to exit inflate on new block */ 37 STORED, /* i: waiting for stored size (length and complement) */ 38 COPY, /* i/o: waiting for input or output to copy stored block */ 39 TABLE, /* i: waiting for dynamic block table lengths */ 40 LENLENS, /* i: waiting for code length code lengths */ 41 CODELENS, /* i: waiting for length/lit and distance code lengths */ 42 LEN, /* i: waiting for length/lit code */ 43 LENEXT, /* i: waiting for length extra bits */ 44 DIST, /* i: waiting for distance code */ 45 DISTEXT, /* i: waiting for distance extra bits */ 46 MATCH, /* o: waiting for output space to copy string */ 47 LIT, /* o: waiting for output space to write literal */ 48 CHECK, /* i: waiting for 32-bit check value */ 49 LENGTH, /* i: waiting for 32-bit length (gzip) */ 50 DONE, /* finished check, done -- remain here until reset */ 51 BAD, /* got a data error -- remain here until reset */ 52 MEM, /* got an inflate() memory error -- remain here until reset */ 53 SYNC /* looking for synchronization bytes to restart inflate() */ 54 } inflate_mode; 55 56 /* 57 State transitions between above modes - 58 59 (most modes can go to the BAD or MEM mode -- not shown for clarity) 60 61 Process header: 62 HEAD -> (gzip) or (zlib) 63 (gzip) -> FLAGS -> TIME -> OS -> EXLEN -> EXTRA -> NAME 64 NAME -> COMMENT -> HCRC -> TYPE 65 (zlib) -> DICTID or TYPE 66 DICTID -> DICT -> TYPE 67 Read deflate blocks: 68 TYPE -> STORED or TABLE or LEN or CHECK 69 STORED -> COPY -> TYPE 70 TABLE -> LENLENS -> CODELENS -> LEN 71 Read deflate codes: 72 LEN -> LENEXT or LIT or TYPE 73 LENEXT -> DIST -> DISTEXT -> MATCH -> LEN 74 LIT -> LEN 75 Process trailer: 76 CHECK -> LENGTH -> DONE 77 */ 78 79 /* state maintained between inflate() calls. Approximately 7K bytes. */ 80 struct inflate_state { 81 inflate_mode mode; /* current inflate mode */ 82 int last; /* true if processing last block */ 83 int wrap; /* bit 0 true for zlib, bit 1 true for gzip */ 84 int havedict; /* true if dictionary provided */ 85 int flags; /* gzip header method and flags (0 if zlib) */ 86 unsigned dmax; /* zlib header max distance (INFLATE_STRICT) */ 87 unsigned long check; /* protected copy of check value */ 88 unsigned long total; /* protected copy of output count */ 89 gz_headerp head; /* where to save gzip header information */ 90 /* sliding window */ 91 unsigned wbits; /* log base 2 of requested window size */ 92 unsigned wsize; /* window size or zero if not using window */ 93 unsigned whave; /* valid bytes in the window */ 94 unsigned write; /* window write index */ 95 unsigned char FAR *window; /* allocated sliding window, if needed */ 96 /* bit accumulator */ 97 unsigned long hold; /* input bit accumulator */ 98 unsigned bits; /* number of bits in "in" */ 99 /* for string and stored block copying */ 100 unsigned length; /* literal or length of data to copy */ 101 unsigned offset; /* distance back to copy string from */ 102 /* for table and code decoding */ 103 unsigned extra; /* extra bits needed */ 104 /* fixed and dynamic code tables */ 105 code const FAR *lencode; /* starting table for length/literal codes */ 106 code const FAR *distcode; /* starting table for distance codes */ 107 unsigned lenbits; /* index bits for lencode */ 108 unsigned distbits; /* index bits for distcode */ 109 /* dynamic table building */ 110 unsigned ncode; /* number of code length code lengths */ 111 unsigned nlen; /* number of length code lengths */ 112 unsigned ndist; /* number of distance code lengths */ 113 unsigned have; /* number of code lengths in lens[] */ 114 code FAR *next; /* next available space in codes[] */ 115 unsigned short lens[320]; /* temporary storage for code lengths */ 116 unsigned short work[288]; /* work area for code table building */ 117 code codes[ENOUGH]; /* space for code tables */ 118 }; 119 120 121 #endif 122