0,0 → 1,122 |
/* inflate.h -- internal inflate state definition |
* Copyright (C) 1995-2009 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: 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 10K 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 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 */ |
}; |