inflate.h

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 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation. Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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/* 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. */
#ifndefNO_GZIP
# defineGUNZIP
#endif

/* Possible inflate modes between inflate() calls */
typedefenum {
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. */
structinflate_state {
z_streampstrm; /* pointer back to this zlib stream */
inflate_modemode; /* current inflate mode */
intlast; /* true if processing last block */
intwrap; /* bit 0 true for zlib, bit 1 true for gzip,
 bit 2 true to validate check value */
inthavedict; /* true if dictionary provided */
intflags; /* gzip header method and flags, 0 if zlib, or
 -1 if raw or no header yet */
unsigneddmax; /* zlib header max distance (INFLATE_STRICT) */
unsigned longcheck; /* protected copy of check value */
unsigned longtotal; /* protected copy of output count */
gz_headerphead; /* where to save gzip header information */
/* sliding window */
unsignedwbits; /* log base 2 of requested window size */
unsignedwsize; /* window size or zero if not using window */
unsignedwhave; /* valid bytes in the window */
unsignedwnext; /* window write index */
unsigned charFAR*window; /* allocated sliding window, if needed */
/* bit accumulator */
unsigned longhold; /* input bit accumulator */
unsignedbits; /* number of bits in "in" */
/* for string and stored block copying */
unsignedlength; /* literal or length of data to copy */
unsignedoffset; /* distance back to copy string from */
/* for table and code decoding */
unsignedextra; /* extra bits needed */
/* fixed and dynamic code tables */
codeconstFAR*lencode; /* starting table for length/literal codes */
codeconstFAR*distcode; /* starting table for distance codes */
unsignedlenbits; /* index bits for lencode */
unsigneddistbits; /* index bits for distcode */
/* dynamic table building */
unsignedncode; /* number of code length code lengths */
unsignednlen; /* number of length code lengths */
unsignedndist; /* number of distance code lengths */
unsignedhave; /* number of code lengths in lens[] */
codeFAR*next; /* next available space in codes[] */
unsigned shortlens[320]; /* temporary storage for code lengths */
unsigned shortwork[288]; /* work area for code table building */
codecodes[ENOUGH]; /* space for code tables */
intsane; /* if false, allow invalid distance too far */
intback; /* bits back of last unprocessed length/lit */
unsignedwas; /* initial length of match */
};