| /* 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 */ |
| }; |
