1/*
2 * Copyright (c) 2008 Apple Inc. All rights reserved.
3 *
4 * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
5 *
6 * This file contains Original Code and/or Modifications of Original Code
7 * as defined in and that are subject to the Apple Public Source License
8 * Version 2.0 (the 'License'). You may not use this file except in
9 * compliance with the License. The rights granted to you under the License
10 * may not be used to create, or enable the creation or redistribution of,
11 * unlawful or unlicensed copies of an Apple operating system, or to
12 * circumvent, violate, or enable the circumvention or violation of, any
13 * terms of an Apple operating system software license agreement.
14 *
15 * Please obtain a copy of the License at
16 * http://www.opensource.apple.com/apsl/ and read it before using this file.
17 *
18 * The Original Code and all software distributed under the License are
19 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
20 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
21 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
22 * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
23 * Please see the License for the specific language governing rights and
24 * limitations under the License.
25 *
26 * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
27 */
28/* inflate.h -- internal inflate state definition
29 * Copyright (C) 1995-2004 Mark Adler
30 * For conditions of distribution and use, see copyright notice in zlib.h
31 */
32
33/* WARNING: this file should *not* be used by applications. It is
34   part of the implementation of the compression library and is
35   subject to change. Applications should only use zlib.h.
36 */
37
38/* define NO_GZIP when compiling if you want to disable gzip header and
39   trailer decoding by inflate().  NO_GZIP would be used to avoid linking in
40   the crc code when it is not needed.  For shared libraries, gzip decoding
41   should be left enabled. */
42#ifndef NO_GZIP
43#  define GUNZIP
44#endif
45
46/* Possible inflate modes between inflate() calls */
47typedef enum {
48    HEAD,       /* i: waiting for magic header */
49    FLAGS,      /* i: waiting for method and flags (gzip) */
50    TIME,       /* i: waiting for modification time (gzip) */
51    OS,         /* i: waiting for extra flags and operating system (gzip) */
52    EXLEN,      /* i: waiting for extra length (gzip) */
53    EXTRA,      /* i: waiting for extra bytes (gzip) */
54    NAME,       /* i: waiting for end of file name (gzip) */
55    COMMENT,    /* i: waiting for end of comment (gzip) */
56    HCRC,       /* i: waiting for header crc (gzip) */
57    DICTID,     /* i: waiting for dictionary check value */
58    DICT,       /* waiting for inflateSetDictionary() call */
59        TYPE,       /* i: waiting for type bits, including last-flag bit */
60        TYPEDO,     /* i: same, but skip check to exit inflate on new block */
61        STORED,     /* i: waiting for stored size (length and complement) */
62        COPY,       /* i/o: waiting for input or output to copy stored block */
63        TABLE,      /* i: waiting for dynamic block table lengths */
64        LENLENS,    /* i: waiting for code length code lengths */
65        CODELENS,   /* i: waiting for length/lit and distance code lengths */
66            LEN,        /* i: waiting for length/lit code */
67            LENEXT,     /* i: waiting for length extra bits */
68            DIST,       /* i: waiting for distance code */
69            DISTEXT,    /* i: waiting for distance extra bits */
70            MATCH,      /* o: waiting for output space to copy string */
71            LIT,        /* o: waiting for output space to write literal */
72    CHECK,      /* i: waiting for 32-bit check value */
73    LENGTH,     /* i: waiting for 32-bit length (gzip) */
74    DONE,       /* finished check, done -- remain here until reset */
75    BAD,        /* got a data error -- remain here until reset */
76    MEM,        /* got an inflate() memory error -- remain here until reset */
77    SYNC        /* looking for synchronization bytes to restart inflate() */
78} inflate_mode;
79
80/*
81    State transitions between above modes -
82
83    (most modes can go to the BAD or MEM mode -- not shown for clarity)
84
85    Process header:
86        HEAD -> (gzip) or (zlib)
87        (gzip) -> FLAGS -> TIME -> OS -> EXLEN -> EXTRA -> NAME
88        NAME -> COMMENT -> HCRC -> TYPE
89        (zlib) -> DICTID or TYPE
90        DICTID -> DICT -> TYPE
91    Read deflate blocks:
92            TYPE -> STORED or TABLE or LEN or CHECK
93            STORED -> COPY -> TYPE
94            TABLE -> LENLENS -> CODELENS -> LEN
95    Read deflate codes:
96                LEN -> LENEXT or LIT or TYPE
97                LENEXT -> DIST -> DISTEXT -> MATCH -> LEN
98                LIT -> LEN
99    Process trailer:
100        CHECK -> LENGTH -> DONE
101 */
102
103/* state maintained between inflate() calls.  Approximately 7K bytes. */
104struct inflate_state {
105    inflate_mode mode;          /* current inflate mode */
106    int last;                   /* true if processing last block */
107    int wrap;                   /* bit 0 true for zlib, bit 1 true for gzip */
108    int havedict;               /* true if dictionary provided */
109    int flags;                  /* gzip header method and flags (0 if zlib) */
110    unsigned dmax;              /* zlib header max distance (INFLATE_STRICT) */
111    unsigned long check;        /* protected copy of check value */
112    unsigned long total;        /* protected copy of output count */
113    gz_headerp head;            /* where to save gzip header information */
114        /* sliding window */
115    unsigned wbits;             /* log base 2 of requested window size */
116    unsigned wsize;             /* window size or zero if not using window */
117    unsigned whave;             /* valid bytes in the window */
118    unsigned write;             /* window write index */
119    unsigned char FAR *window;  /* allocated sliding window, if needed */
120        /* bit accumulator */
121    unsigned long hold;         /* input bit accumulator */
122    unsigned bits;              /* number of bits in "in" */
123        /* for string and stored block copying */
124    unsigned length;            /* literal or length of data to copy */
125    unsigned offset;            /* distance back to copy string from */
126        /* for table and code decoding */
127    unsigned extra;             /* extra bits needed */
128        /* fixed and dynamic code tables */
129    code const FAR *lencode;    /* starting table for length/literal codes */
130    code const FAR *distcode;   /* starting table for distance codes */
131    unsigned lenbits;           /* index bits for lencode */
132    unsigned distbits;          /* index bits for distcode */
133        /* dynamic table building */
134    unsigned ncode;             /* number of code length code lengths */
135    unsigned nlen;              /* number of length code lengths */
136    unsigned ndist;             /* number of distance code lengths */
137    unsigned have;              /* number of code lengths in lens[] */
138    code FAR *next;             /* next available space in codes[] */
139    unsigned short lens[320];   /* temporary storage for code lengths */
140    unsigned short work[288];   /* work area for code table building */
141    code codes[ENOUGH];         /* space for code tables */
142};
143