inflate.h
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上传日期:2013-08-04
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文件大小:6k
- /* inflate.h -- internal inflate state definition
- * Copyright (C) 1995-2003 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 */
- #ifdef GUNZIP
- 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) */
- #endif
- 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 */
- #ifdef GUNZIP
- LENGTH, /* i: waiting for 32-bit length (gzip) */
- #endif
- 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 long check; /* protected copy of check value */
- unsigned long total; /* protected copy of output count */
- /* 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 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 */
- };