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Diffstat (limited to 'modules/zlib/src/inflate.h')
| -rw-r--r-- | modules/zlib/src/inflate.h | 126 |
1 files changed, 126 insertions, 0 deletions
diff --git a/modules/zlib/src/inflate.h b/modules/zlib/src/inflate.h new file mode 100644 index 0000000000..f127b6b1fa --- /dev/null +++ b/modules/zlib/src/inflate.h @@ -0,0 +1,126 @@ +/* inflate.h -- internal inflate state definition + * Copyright (C) 1995-2019 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, or + -1 if raw or no header yet */ + 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 */ +}; |