1 #ifndef INFLATE_H 2 #define INFLATE_H 3 4 /* inflate.h -- internal inflate state definition 5 * Copyright (C) 1995-2004 Mark Adler 6 * For conditions of distribution and use, see copyright notice in zlib.h 7 */ 8 9 /* WARNING: this file should *not* be used by applications. It is 10 part of the implementation of the compression library and is 11 subject to change. Applications should only use zlib.h. 12 */ 13 14 #include "inftrees.h" 15 16 /* Possible inflate modes between inflate() calls */ 17 typedef enum { 18 HEAD, /* i: waiting for magic header */ 19 FLAGS, /* i: waiting for method and flags (gzip) */ 20 TIME, /* i: waiting for modification time (gzip) */ 21 OS, /* i: waiting for extra flags and operating system (gzip) */ 22 EXLEN, /* i: waiting for extra length (gzip) */ 23 EXTRA, /* i: waiting for extra bytes (gzip) */ 24 NAME, /* i: waiting for end of file name (gzip) */ 25 COMMENT, /* i: waiting for end of comment (gzip) */ 26 HCRC, /* i: waiting for header crc (gzip) */ 27 DICTID, /* i: waiting for dictionary check value */ 28 DICT, /* waiting for inflateSetDictionary() call */ 29 TYPE, /* i: waiting for type bits, including last-flag bit */ 30 TYPEDO, /* i: same, but skip check to exit inflate on new block */ 31 STORED, /* i: waiting for stored size (length and complement) */ 32 COPY, /* i/o: waiting for input or output to copy stored block */ 33 TABLE, /* i: waiting for dynamic block table lengths */ 34 LENLENS, /* i: waiting for code length code lengths */ 35 CODELENS, /* i: waiting for length/lit and distance code lengths */ 36 LEN, /* i: waiting for length/lit code */ 37 LENEXT, /* i: waiting for length extra bits */ 38 DIST, /* i: waiting for distance code */ 39 DISTEXT, /* i: waiting for distance extra bits */ 40 MATCH, /* o: waiting for output space to copy string */ 41 LIT, /* o: waiting for output space to write literal */ 42 CHECK, /* i: waiting for 32-bit check value */ 43 LENGTH, /* i: waiting for 32-bit length (gzip) */ 44 DONE, /* finished check, done -- remain here until reset */ 45 BAD, /* got a data error -- remain here until reset */ 46 MEM, /* got an inflate() memory error -- remain here until reset */ 47 SYNC /* looking for synchronization bytes to restart inflate() */ 48 } inflate_mode; 49 50 /* 51 State transitions between above modes - 52 53 (most modes can go to the BAD or MEM mode -- not shown for clarity) 54 55 Process header: 56 HEAD -> (gzip) or (zlib) 57 (gzip) -> FLAGS -> TIME -> OS -> EXLEN -> EXTRA -> NAME 58 NAME -> COMMENT -> HCRC -> TYPE 59 (zlib) -> DICTID or TYPE 60 DICTID -> DICT -> TYPE 61 Read deflate blocks: 62 TYPE -> STORED or TABLE or LEN or CHECK 63 STORED -> COPY -> TYPE 64 TABLE -> LENLENS -> CODELENS -> LEN 65 Read deflate codes: 66 LEN -> LENEXT or LIT or TYPE 67 LENEXT -> DIST -> DISTEXT -> MATCH -> LEN 68 LIT -> LEN 69 Process trailer: 70 CHECK -> LENGTH -> DONE 71 */ 72 73 /* state maintained between inflate() calls. Approximately 7K bytes. */ 74 struct inflate_state { 75 inflate_mode mode; /* current inflate mode */ 76 int last; /* true if processing last block */ 77 int wrap; /* bit 0 true for zlib, bit 1 true for gzip */ 78 int havedict; /* true if dictionary provided */ 79 int flags; /* gzip header method and flags (0 if zlib) */ 80 unsigned dmax; /* zlib header max distance (INFLATE_STRICT) */ 81 unsigned long check; /* protected copy of check value */ 82 unsigned long total; /* protected copy of output count */ 83 /* gz_headerp head; */ /* where to save gzip header information */ 84 /* sliding window */ 85 unsigned wbits; /* log base 2 of requested window size */ 86 unsigned wsize; /* window size or zero if not using window */ 87 unsigned whave; /* valid bytes in the window */ 88 unsigned write; /* window write index */ 89 unsigned char *window; /* allocated sliding window, if needed */ 90 /* bit accumulator */ 91 unsigned long hold; /* input bit accumulator */ 92 unsigned bits; /* number of bits in "in" */ 93 /* for string and stored block copying */ 94 unsigned length; /* literal or length of data to copy */ 95 unsigned offset; /* distance back to copy string from */ 96 /* for table and code decoding */ 97 unsigned extra; /* extra bits needed */ 98 /* fixed and dynamic code tables */ 99 code const *lencode; /* starting table for length/literal codes */ 100 code const *distcode; /* starting table for distance codes */ 101 unsigned lenbits; /* index bits for lencode */ 102 unsigned distbits; /* index bits for distcode */ 103 /* dynamic table building */ 104 unsigned ncode; /* number of code length code lengths */ 105 unsigned nlen; /* number of length code lengths */ 106 unsigned ndist; /* number of distance code lengths */ 107 unsigned have; /* number of code lengths in lens[] */ 108 code *next; /* next available space in codes[] */ 109 unsigned short lens[320]; /* temporary storage for code lengths */ 110 unsigned short work[288]; /* work area for code table building */ 111 code codes[ENOUGH]; /* space for code tables */ 112 }; 113 114 /* Reverse the bytes in a 32-bit value */ 115 #define REVERSE(q) \ 116 ((((q) >> 24) & 0xff) + (((q) >> 8) & 0xff00) + \ 117 (((q) & 0xff00) << 8) + (((q) & 0xff) << 24)) 118 119 #endif 120