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inflate.h
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1/* inflate.h -- internal inflate state definition
2 * Copyright (C) 1995-2016 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 = 16180, /* 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: same as COPY below, but only first time in */
36 COPY, /* i/o: waiting for input or output to copy stored block */
37 TABLE, /* i: waiting for dynamic block table lengths */
38 LENLENS, /* i: waiting for code length code lengths */
39 CODELENS, /* i: waiting for length/lit and distance code lengths */
40 LEN_, /* i: same as LEN below, but only first time in */
41 LEN, /* i: waiting for length/lit/eob 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 BAD or MEM on error -- not shown for clarity)
59
60 Process header:
61 HEAD -> (gzip) or (zlib) or (raw)
62 (gzip) -> FLAGS -> TIME -> OS -> EXLEN -> EXTRA -> NAME -> COMMENT ->
63 HCRC -> TYPE
64 (zlib) -> DICTID or TYPE
65 DICTID -> DICT -> TYPE
66 (raw) -> TYPEDO
67 Read deflate blocks:
68 TYPE -> TYPEDO -> STORED or TABLE or LEN_ or CHECK
69 STORED -> COPY_ -> COPY -> TYPE
70 TABLE -> LENLENS -> CODELENS -> LEN_
71 LEN_ -> LEN
72 Read deflate codes in fixed or dynamic block:
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, not
81 including the allocated sliding window, which is up to 32K bytes. */
82 struct inflate_state {
83 z_streamp strm; /* pointer back to this zlib stream */
84 inflate_mode mode; /* current inflate mode */
85 int last; /* true if processing last block */
86 int wrap; /* bit 0 true for zlib, bit 1 true for gzip,
87 bit 2 true to validate check value */
88 int havedict; /* true if dictionary provided */
89 int flags; /* gzip header method and flags (0 if zlib) */
90 unsigned dmax; /* zlib header max distance (INFLATE_STRICT) */
91 unsigned long check; /* protected copy of check value */
92 unsigned long total; /* protected copy of output count */
93 gz_headerp head; /* where to save gzip header information */
94 /* sliding window */
95 unsigned wbits; /* log base 2 of requested window size */
96 unsigned wsize; /* window size or zero if not using window */
97 unsigned whave; /* valid bytes in the window */
98 unsigned wnext; /* window write index */
99 unsigned char FAR *window; /* allocated sliding window, if needed */
100 /* bit accumulator */
101 unsigned long hold; /* input bit accumulator */
102 unsigned bits; /* number of bits in "in" */
103 /* for string and stored block copying */
104 unsigned length; /* literal or length of data to copy */
105 unsigned offset; /* distance back to copy string from */
106 /* for table and code decoding */
107 unsigned extra; /* extra bits needed */
108 /* fixed and dynamic code tables */
109 code const FAR *lencode; /* starting table for length/literal codes */
110 code const FAR *distcode; /* starting table for distance codes */
111 unsigned lenbits; /* index bits for lencode */
112 unsigned distbits; /* index bits for distcode */
113 /* dynamic table building */
114 unsigned ncode; /* number of code length code lengths */
115 unsigned nlen; /* number of length code lengths */
116 unsigned ndist; /* number of distance code lengths */
117 unsigned have; /* number of code lengths in lens[] */
118 code FAR *next; /* next available space in codes[] */
119 unsigned short lens[320]; /* temporary storage for code lengths */
120 unsigned short work[288]; /* work area for code table building */
121 code codes[ENOUGH]; /* space for code tables */
122 int sane; /* if false, allow invalid distance too far */
123 int back; /* bits back of last unprocessed length/lit */
124 unsigned was; /* initial length of match */
125};
inflate_mode
inflate_mode
Definition: inflate.h:20
HEAD
@ HEAD
Definition: inflate.h:21
MATCH
@ MATCH
Definition: inflate.h:45
DICT
@ DICT
Definition: inflate.h:31
TABLE
@ TABLE
Definition: inflate.h:37
LENGTH
@ LENGTH
Definition: inflate.h:48
FLAGS
@ FLAGS
Definition: inflate.h:22
LIT
@ LIT
Definition: inflate.h:46
SYNC
@ SYNC
Definition: inflate.h:52
OS
@ OS
Definition: inflate.h:24
EXLEN
@ EXLEN
Definition: inflate.h:25
MEM
@ MEM
Definition: inflate.h:51
NAME
@ NAME
Definition: inflate.h:27
STORED
@ STORED
Definition: inflate.h:34
CODELENS
@ CODELENS
Definition: inflate.h:39
DICTID
@ DICTID
Definition: inflate.h:30
DONE
@ DONE
Definition: inflate.h:49
TYPEDO
@ TYPEDO
Definition: inflate.h:33
COMMENT
@ COMMENT
Definition: inflate.h:28
LENLENS
@ LENLENS
Definition: inflate.h:38
TYPE
@ TYPE
Definition: inflate.h:32
COPY
@ COPY
Definition: inflate.h:36
LEN_
@ LEN_
Definition: inflate.h:40
COPY_
@ COPY_
Definition: inflate.h:35
DIST
@ DIST
Definition: inflate.h:43
LENEXT
@ LENEXT
Definition: inflate.h:42
HCRC
@ HCRC
Definition: inflate.h:29
TIME
@ TIME
Definition: inflate.h:23
CHECK
@ CHECK
Definition: inflate.h:47
DISTEXT
@ DISTEXT
Definition: inflate.h:44
BAD
@ BAD
Definition: inflate.h:50
LEN
@ LEN
Definition: inflate.h:41
EXTRA
@ EXTRA
Definition: inflate.h:26
ENOUGH
#define ENOUGH
Definition: inftrees.h:51
code
Definition: inftrees.h:24
inflate_state
Definition: inflate.h:82
inflate_state::was
unsigned was
Definition: inflate.h:124
inflate_state::distcode
code const FAR * distcode
Definition: inflate.h:110
inflate_state::wnext
unsigned wnext
Definition: inflate.h:98
inflate_state::havedict
int havedict
Definition: inflate.h:88
inflate_state::lenbits
unsigned lenbits
Definition: inflate.h:111
inflate_state::ndist
unsigned ndist
Definition: inflate.h:116
inflate_state::lencode
code const FAR * lencode
Definition: inflate.h:109
inflate_state::nlen
unsigned nlen
Definition: inflate.h:115
inflate_state::have
unsigned have
Definition: inflate.h:117
inflate_state::length
unsigned length
Definition: inflate.h:104
inflate_state::hold
unsigned long hold
Definition: inflate.h:101
inflate_state::extra
unsigned extra
Definition: inflate.h:107
inflate_state::ncode
unsigned ncode
Definition: inflate.h:114
inflate_state::strm
z_streamp strm
Definition: inflate.h:83
inflate_state::whave
unsigned whave
Definition: inflate.h:97
inflate_state::wbits
unsigned wbits
Definition: inflate.h:95
inflate_state::work
unsigned short work[288]
Definition: inflate.h:120
inflate_state::next
code FAR * next
Definition: inflate.h:118
inflate_state::distbits
unsigned distbits
Definition: inflate.h:112
inflate_state::sane
int sane
Definition: inflate.h:122
inflate_state::wrap
int wrap
Definition: inflate.h:86
inflate_state::mode
inflate_mode mode
Definition: inflate.h:84
inflate_state::window
unsigned char FAR * window
Definition: inflate.h:99
inflate_state::flags
int flags
Definition: inflate.h:89
inflate_state::lens
unsigned short lens[320]
Definition: inflate.h:119
inflate_state::head
gz_headerp head
Definition: inflate.h:93
inflate_state::bits
unsigned bits
Definition: inflate.h:102
inflate_state::last
int last
Definition: inflate.h:85
inflate_state::back
int back
Definition: inflate.h:123
inflate_state::wsize
unsigned wsize
Definition: inflate.h:96
inflate_state::dmax
unsigned dmax
Definition: inflate.h:90
inflate_state::check
unsigned long check
Definition: inflate.h:91
inflate_state::offset
unsigned offset
Definition: inflate.h:105
inflate_state::codes
code codes[ENOUGH]
Definition: inflate.h:121
inflate_state::total
unsigned long total
Definition: inflate.h:92
FAR
#define FAR
Definition: zconf.h:387
gz_headerp
gz_header FAR * gz_headerp
Definition: zlib.h:131
z_streamp
z_stream FAR * z_streamp
Definition: zlib.h:108