Annotation of sys/lib/libz/inflate.h, Revision 1.1.1.1
1.1 nbrk 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: /* Possible inflate modes between inflate() calls */
20: typedef enum {
21: HEAD, /* i: waiting for magic header */
22: FLAGS, /* i: waiting for method and flags (gzip) */
23: TIME, /* i: waiting for modification time (gzip) */
24: OS, /* i: waiting for extra flags and operating system (gzip) */
25: EXLEN, /* i: waiting for extra length (gzip) */
26: EXTRA, /* i: waiting for extra bytes (gzip) */
27: NAME, /* i: waiting for end of file name (gzip) */
28: COMMENT, /* i: waiting for end of comment (gzip) */
29: HCRC, /* i: waiting for header crc (gzip) */
30: DICTID, /* i: waiting for dictionary check value */
31: DICT, /* waiting for inflateSetDictionary() call */
32: TYPE, /* i: waiting for type bits, including last-flag bit */
33: TYPEDO, /* i: same, but skip check to exit inflate on new block */
34: STORED, /* i: waiting for stored size (length and complement) */
35: COPY, /* i/o: waiting for input or output to copy stored block */
36: TABLE, /* i: waiting for dynamic block table lengths */
37: LENLENS, /* i: waiting for code length code lengths */
38: CODELENS, /* i: waiting for length/lit and distance code lengths */
39: LEN, /* i: waiting for length/lit code */
40: LENEXT, /* i: waiting for length extra bits */
41: DIST, /* i: waiting for distance code */
42: DISTEXT, /* i: waiting for distance extra bits */
43: MATCH, /* o: waiting for output space to copy string */
44: LIT, /* o: waiting for output space to write literal */
45: CHECK, /* i: waiting for 32-bit check value */
46: LENGTH, /* i: waiting for 32-bit length (gzip) */
47: DONE, /* finished check, done -- remain here until reset */
48: BAD, /* got a data error -- remain here until reset */
49: MEM, /* got an inflate() memory error -- remain here until reset */
50: SYNC /* looking for synchronization bytes to restart inflate() */
51: } inflate_mode;
52:
53: /*
54: State transitions between above modes -
55:
56: (most modes can go to the BAD or MEM mode -- not shown for clarity)
57:
58: Process header:
59: HEAD -> (gzip) or (zlib)
60: (gzip) -> FLAGS -> TIME -> OS -> EXLEN -> EXTRA -> NAME
61: NAME -> COMMENT -> HCRC -> TYPE
62: (zlib) -> DICTID or TYPE
63: DICTID -> DICT -> TYPE
64: Read deflate blocks:
65: TYPE -> STORED or TABLE or LEN or CHECK
66: STORED -> COPY -> TYPE
67: TABLE -> LENLENS -> CODELENS -> LEN
68: Read deflate codes:
69: LEN -> LENEXT or LIT or TYPE
70: LENEXT -> DIST -> DISTEXT -> MATCH -> LEN
71: LIT -> LEN
72: Process trailer:
73: CHECK -> LENGTH -> DONE
74: */
75:
76: /* state maintained between inflate() calls. Approximately 7K bytes. */
77: struct inflate_state {
78: inflate_mode mode; /* current inflate mode */
79: int last; /* true if processing last block */
80: int wrap; /* bit 0 true for zlib, bit 1 true for gzip */
81: int havedict; /* true if dictionary provided */
82: int flags; /* gzip header method and flags (0 if zlib) */
83: unsigned dmax; /* zlib header max distance (INFLATE_STRICT) */
84: unsigned long check; /* protected copy of check value */
85: unsigned long total; /* protected copy of output count */
86: gz_headerp head; /* where to save gzip header information */
87: /* sliding window */
88: unsigned wbits; /* log base 2 of requested window size */
89: unsigned wsize; /* window size or zero if not using window */
90: unsigned whave; /* valid bytes in the window */
91: unsigned write; /* window write index */
92: unsigned char FAR *window; /* allocated sliding window, if needed */
93: /* bit accumulator */
94: unsigned long hold; /* input bit accumulator */
95: unsigned bits; /* number of bits in "in" */
96: /* for string and stored block copying */
97: unsigned length; /* literal or length of data to copy */
98: unsigned offset; /* distance back to copy string from */
99: /* for table and code decoding */
100: unsigned extra; /* extra bits needed */
101: /* fixed and dynamic code tables */
102: code const FAR *lencode; /* starting table for length/literal codes */
103: code const FAR *distcode; /* starting table for distance codes */
104: unsigned lenbits; /* index bits for lencode */
105: unsigned distbits; /* index bits for distcode */
106: /* dynamic table building */
107: unsigned ncode; /* number of code length code lengths */
108: unsigned nlen; /* number of length code lengths */
109: unsigned ndist; /* number of distance code lengths */
110: unsigned have; /* number of code lengths in lens[] */
111: code FAR *next; /* next available space in codes[] */
112: unsigned short lens[320]; /* temporary storage for code lengths */
113: unsigned short work[288]; /* work area for code table building */
114: code codes[ENOUGH]; /* space for code tables */
115: };
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