inflate.h
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/* inflate.h -- internal inflate state definition
* Copyright (C) 1995-2016 Mark Adler
* For conditions of distribution and use, see copyright notice in zlib.h
*/
/* WARNING: this file should *not* be used by applications. It is
part of the implementation of the compression library and is
subject to change. Applications should only use zlib.h.
*/
/* define NO_GZIP when compiling if you want to disable gzip header and
trailer decoding by inflate(). NO_GZIP would be used to avoid linking in
the crc code when it is not needed. For shared libraries, gzip decoding
should be left enabled. */
#ifndef NO_GZIP
# define GUNZIP
#endif
/* Possible inflate modes between inflate() calls */
typedef enum {
HEAD = 16180, /* i: waiting for magic header */
FLAGS, /* i: waiting for method and flags (gzip) */
TIME, /* i: waiting for modification time (gzip) */
OS, /* i: waiting for extra flags and operating system (gzip) */
EXLEN, /* i: waiting for extra length (gzip) */
EXTRA, /* i: waiting for extra bytes (gzip) */
NAME, /* i: waiting for end of file name (gzip) */
COMMENT, /* i: waiting for end of comment (gzip) */
HCRC, /* i: waiting for header crc (gzip) */
DICTID, /* i: waiting for dictionary check value */
DICT, /* waiting for inflateSetDictionary() call */
TYPE, /* i: waiting for type bits, including last-flag bit */
TYPEDO, /* i: same, but skip check to exit inflate on new block */
STORED, /* i: waiting for stored size (length and complement) */
COPY_, /* i/o: same as COPY below, but only first time in */
COPY, /* i/o: waiting for input or output to copy stored block */
TABLE, /* i: waiting for dynamic block table lengths */
LENLENS, /* i: waiting for code length code lengths */
CODELENS, /* i: waiting for length/lit and distance code lengths */
LEN_, /* i: same as LEN below, but only first time in */
LEN, /* i: waiting for length/lit/eob code */
LENEXT, /* i: waiting for length extra bits */
DIST, /* i: waiting for distance code */
DISTEXT, /* i: waiting for distance extra bits */
MATCH, /* o: waiting for output space to copy string */
LIT, /* o: waiting for output space to write literal */
CHECK, /* i: waiting for 32-bit check value */
LENGTH, /* i: waiting for 32-bit length (gzip) */
DONE, /* finished check, done -- remain here until reset */
BAD, /* got a data error -- remain here until reset */
MEM, /* got an inflate() memory error -- remain here until reset */
SYNC /* looking for synchronization bytes to restart inflate() */
} inflate_mode;
/*
State transitions between above modes -
(most modes can go to BAD or MEM on error -- not shown for clarity)
Process header:
HEAD -> (gzip) or (zlib) or (raw)
(gzip) -> FLAGS -> TIME -> OS -> EXLEN -> EXTRA -> NAME -> COMMENT ->
HCRC -> TYPE
(zlib) -> DICTID or TYPE
DICTID -> DICT -> TYPE
(raw) -> TYPEDO
Read deflate blocks:
TYPE -> TYPEDO -> STORED or TABLE or LEN_ or CHECK
STORED -> COPY_ -> COPY -> TYPE
TABLE -> LENLENS -> CODELENS -> LEN_
LEN_ -> LEN
Read deflate codes in fixed or dynamic block:
LEN -> LENEXT or LIT or TYPE
LENEXT -> DIST -> DISTEXT -> MATCH -> LEN
LIT -> LEN
Process trailer:
CHECK -> LENGTH -> DONE
*/
/* State maintained between inflate() calls -- approximately 7K bytes, not
including the allocated sliding window, which is up to 32K bytes. */
struct inflate_state {
z_streamp strm; /* pointer back to this zlib stream */
inflate_mode mode; /* current inflate mode */
int last; /* true if processing last block */
int wrap; /* bit 0 true for zlib, bit 1 true for gzip,
bit 2 true to validate check value */
int havedict; /* true if dictionary provided */
int flags; /* gzip header method and flags (0 if zlib) */
unsigned dmax; /* zlib header max distance (INFLATE_STRICT) */
unsigned long check; /* protected copy of check value */
unsigned long total; /* protected copy of output count */
gz_headerp head; /* where to save gzip header information */
/* sliding window */
unsigned wbits; /* log base 2 of requested window size */
unsigned wsize; /* window size or zero if not using window */
unsigned whave; /* valid bytes in the window */
unsigned wnext; /* window write index */
unsigned char FAR *window; /* allocated sliding window, if needed */
/* bit accumulator */
unsigned long hold; /* input bit accumulator */
unsigned bits; /* number of bits in "in" */
/* for string and stored block copying */
unsigned length; /* literal or length of data to copy */
unsigned offset; /* distance back to copy string from */
/* for table and code decoding */
unsigned extra; /* extra bits needed */
/* fixed and dynamic code tables */
code const FAR *lencode; /* starting table for length/literal codes */
code const FAR *distcode; /* starting table for distance codes */
unsigned lenbits; /* index bits for lencode */
unsigned distbits; /* index bits for distcode */
/* dynamic table building */
unsigned ncode; /* number of code length code lengths */
unsigned nlen; /* number of length code lengths */
unsigned ndist; /* number of distance code lengths */
unsigned have; /* number of code lengths in lens[] */
code FAR *next; /* next available space in codes[] */
unsigned short lens[320]; /* temporary storage for code lengths */
unsigned short work[288]; /* work area for code table building */
code codes[ENOUGH]; /* space for code tables */
int sane; /* if false, allow invalid distance too far */
int back; /* bits back of last unprocessed length/lit */
unsigned was; /* initial length of match */
};
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