inflate.h
/* inflate.h -- internal inflate state definition
* Copyright (C) 1995-2004 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, /* 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: 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: waiting for length/lit 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 the BAD or MEM mode -- not shown for clarity)
Process header:
HEAD -> (gzip) or (zlib)
(gzip) -> FLAGS -> TIME -> OS -> EXLEN -> EXTRA -> NAME
NAME -> COMMENT -> HCRC -> TYPE
(zlib) -> DICTID or TYPE
DICTID -> DICT -> TYPE
Read deflate blocks:
TYPE -> STORED or TABLE or LEN or CHECK
STORED -> COPY -> TYPE
TABLE -> LENLENS -> CODELENS -> LEN
Read deflate codes:
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. */
struct inflate_state {
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 */
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 int check; /* protected copy of check value */
unsigned int 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 write; /* window write index */
unsigned char FAR *window; /* allocated sliding window, if needed */
/* bit accumulator */
unsigned int 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 */
};
inflate_state::dmax
unsigned dmax
Definition: inflate.h:83
inflate_state::window
unsigned char FAR * window
Definition: inflate.h:92
inflate_state::wrap
int wrap
Definition: inflate.h:80
inflate_state::codes
code codes[ENOUGH]
Definition: inflate.h:114
inflate_state
Definition: inflate.h:77
inflate_state::flags
int flags
Definition: inflate.h:82
inflate_state::wsize
unsigned wsize
Definition: inflate.h:89
inflate_state::whave
unsigned whave
Definition: inflate.h:90
inflate_state::next
code FAR * next
Definition: inflate.h:111
inflate_state::nlen
unsigned nlen
Definition: inflate.h:108
inflate_state::lenbits
unsigned lenbits
Definition: inflate.h:104
inflate_state::lens
unsigned short lens[320]
Definition: inflate.h:112
inflate_state::havedict
int havedict
Definition: inflate.h:81
inflate_state::head
gz_headerp head
Definition: inflate.h:86
inflate_state::write
unsigned write
Definition: inflate.h:91
inflate_state::work
unsigned short work[288]
Definition: inflate.h:113
inflate_state::bits
unsigned bits
Definition: inflate.h:95
inflate_state::check
unsigned int check
Definition: inflate.h:84
inflate_state::extra
unsigned extra
Definition: inflate.h:100
inflate_state::lencode
const code FAR * lencode
Definition: inflate.h:102
inflate_state::have
unsigned have
Definition: inflate.h:110
inflate_state::hold
unsigned int hold
Definition: inflate.h:94
inflate_state::last
int last
Definition: inflate.h:79
inflate_state::offset
unsigned offset
Definition: inflate.h:98
inflate_state::ndist
unsigned ndist
Definition: inflate.h:109
inflate_state::ncode
unsigned ncode
Definition: inflate.h:107
inflate_state::mode
inflate_mode mode
Definition: inflate.h:78
inflate_state::distcode
const code FAR * distcode
Definition: inflate.h:103
code
Definition: inftrees.h:24
inflate_state::total
unsigned int total
Definition: inflate.h:85
inflate_state::wbits
unsigned wbits
Definition: inflate.h:88
inflate_state::distbits
unsigned distbits
Definition: inflate.h:105
inflate_state::length
unsigned length
Definition: inflate.h:97