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