1 /*
2 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
3 *
4 * This code is free software; you can redistribute it and/or modify it
5 * under the terms of the GNU General Public License version 2 only, as
6 * published by the Free Software Foundation. Oracle designates this
7 * particular file as subject to the "Classpath" exception as provided
8 * by Oracle in the LICENSE file that accompanied this code.
9 *
10 * This code is distributed in the hope that it will be useful, but WITHOUT
11 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
12 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
13 * version 2 for more details (a copy is included in the LICENSE file that
14 * accompanied this code).
15 *
16 * You should have received a copy of the GNU General Public License version
17 * 2 along with this work; if not, write to the Free Software Foundation,
18 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
19 *
20 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
21 * or visit www.oracle.com if you need additional information or have any
22 * questions.
23 */
24
25 /* inflate.h -- internal inflate state definition
26 * Copyright (C) 1995-2009 Mark Adler
27 * For conditions of distribution and use, see copyright notice in zlib.h
28 */
29
30 /* WARNING: this file should *not* be used by applications. It is
31 part of the implementation of the compression library and is
32 subject to change. Applications should only use zlib.h.
33 */
34
35 /* define NO_GZIP when compiling if you want to disable gzip header and
36 trailer decoding by inflate(). NO_GZIP would be used to avoid linking in
37 the crc code when it is not needed. For shared libraries, gzip decoding
38 should be left enabled. */
39 #ifndef NO_GZIP
40 # define GUNZIP
41 #endif
42
43 /* Possible inflate modes between inflate() calls */
44 typedef enum {
45 HEAD, /* i: waiting for magic header */
46 FLAGS, /* i: waiting for method and flags (gzip) */
47 TIME, /* i: waiting for modification time (gzip) */
48 OS, /* i: waiting for extra flags and operating system (gzip) */
49 EXLEN, /* i: waiting for extra length (gzip) */
50 EXTRA, /* i: waiting for extra bytes (gzip) */
51 NAME, /* i: waiting for end of file name (gzip) */
52 COMMENT, /* i: waiting for end of comment (gzip) */
53 HCRC, /* i: waiting for header crc (gzip) */
54 DICTID, /* i: waiting for dictionary check value */
55 DICT, /* waiting for inflateSetDictionary() call */
56 TYPE, /* i: waiting for type bits, including last-flag bit */
57 TYPEDO, /* i: same, but skip check to exit inflate on new block */
58 STORED, /* i: waiting for stored size (length and complement) */
59 COPY_, /* i/o: same as COPY below, but only first time in */
60 COPY, /* i/o: waiting for input or output to copy stored block */
61 TABLE, /* i: waiting for dynamic block table lengths */
62 LENLENS, /* i: waiting for code length code lengths */
63 CODELENS, /* i: waiting for length/lit and distance code lengths */
64 LEN_, /* i: same as LEN below, but only first time in */
65 LEN, /* i: waiting for length/lit/eob code */
66 LENEXT, /* i: waiting for length extra bits */
67 DIST, /* i: waiting for distance code */
68 DISTEXT, /* i: waiting for distance extra bits */
69 MATCH, /* o: waiting for output space to copy string */
70 LIT, /* o: waiting for output space to write literal */
71 CHECK, /* i: waiting for 32-bit check value */
72 LENGTH, /* i: waiting for 32-bit length (gzip) */
73 DONE, /* finished check, done -- remain here until reset */
74 BAD, /* got a data error -- remain here until reset */
75 MEM, /* got an inflate() memory error -- remain here until reset */
76 SYNC /* looking for synchronization bytes to restart inflate() */
77 } inflate_mode;
78
79 /*
80 State transitions between above modes -
81
82 (most modes can go to BAD or MEM on error -- not shown for clarity)
83
84 Process header:
85 HEAD -> (gzip) or (zlib) or (raw)
86 (gzip) -> FLAGS -> TIME -> OS -> EXLEN -> EXTRA -> NAME -> COMMENT ->
87 HCRC -> TYPE
88 (zlib) -> DICTID or TYPE
89 DICTID -> DICT -> TYPE
90 (raw) -> TYPEDO
91 Read deflate blocks:
92 TYPE -> TYPEDO -> STORED or TABLE or LEN_ or CHECK
93 STORED -> COPY_ -> COPY -> TYPE
94 TABLE -> LENLENS -> CODELENS -> LEN_
95 LEN_ -> LEN
96 Read deflate codes in fixed or dynamic block:
97 LEN -> LENEXT or LIT or TYPE
98 LENEXT -> DIST -> DISTEXT -> MATCH -> LEN
99 LIT -> LEN
100 Process trailer:
101 CHECK -> LENGTH -> DONE
102 */
103
104 /* state maintained between inflate() calls. Approximately 10K bytes. */
105 struct inflate_state {
106 inflate_mode mode; /* current inflate mode */
107 int last; /* true if processing last block */
108 int wrap; /* bit 0 true for zlib, bit 1 true for gzip */
109 int havedict; /* true if dictionary provided */
110 int flags; /* gzip header method and flags (0 if zlib) */
111 unsigned dmax; /* zlib header max distance (INFLATE_STRICT) */
112 unsigned long check; /* protected copy of check value */
113 unsigned long total; /* protected copy of output count */
114 gz_headerp head; /* where to save gzip header information */
115 /* sliding window */
116 unsigned wbits; /* log base 2 of requested window size */
117 unsigned wsize; /* window size or zero if not using window */
118 unsigned whave; /* valid bytes in the window */
119 unsigned wnext; /* window write index */
120 unsigned char FAR *window; /* allocated sliding window, if needed */
121 /* bit accumulator */
122 unsigned long hold; /* input bit accumulator */
123 unsigned bits; /* number of bits in "in" */
124 /* for string and stored block copying */
125 unsigned length; /* literal or length of data to copy */
126 unsigned offset; /* distance back to copy string from */
127 /* for table and code decoding */
128 unsigned extra; /* extra bits needed */
129 /* fixed and dynamic code tables */
130 code const FAR *lencode; /* starting table for length/literal codes */
131 code const FAR *distcode; /* starting table for distance codes */
132 unsigned lenbits; /* index bits for lencode */
133 unsigned distbits; /* index bits for distcode */
134 /* dynamic table building */
135 unsigned ncode; /* number of code length code lengths */
136 unsigned nlen; /* number of length code lengths */
137 unsigned ndist; /* number of distance code lengths */
138 unsigned have; /* number of code lengths in lens[] */
139 code FAR *next; /* next available space in codes[] */
140 unsigned short lens[320]; /* temporary storage for code lengths */
141 unsigned short work[288]; /* work area for code table building */
142 code codes[ENOUGH]; /* space for code tables */
143 int sane; /* if false, allow invalid distance too far */
144 int back; /* bits back of last unprocessed length/lit */
145 unsigned was; /* initial length of match */
146 };