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a163d034fa
Approved by: trb
1079 lines
37 KiB
C
1079 lines
37 KiB
C
/*
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* Most parts of this file are not covered by:
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* ----------------------------------------------------------------------------
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* "THE BEER-WARE LICENSE" (Revision 42):
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* <phk@FreeBSD.org> wrote this file. As long as you retain this notice you
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* can do whatever you want with this stuff. If we meet some day, and you think
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* this stuff is worth it, you can buy me a beer in return. Poul-Henning Kamp
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* ----------------------------------------------------------------------------
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*
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* $FreeBSD$
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*
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*
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*/
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#include <sys/param.h>
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#include <sys/inflate.h>
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#ifdef _KERNEL
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#include <sys/systm.h>
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#include <sys/kernel.h>
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#endif
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#include <sys/malloc.h>
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#ifdef _KERNEL
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static MALLOC_DEFINE(M_GZIP, "Gzip trees", "Gzip trees");
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#endif
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/* needed to make inflate() work */
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#define uch u_char
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#define ush u_short
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#define ulg u_long
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/* Stuff to make inflate() work */
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#ifdef _KERNEL
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#define memzero(dest,len) bzero(dest,len)
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#endif
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#define NOMEMCPY
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#ifdef _KERNEL
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#define FPRINTF printf
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#else
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extern void putstr (char *);
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#define FPRINTF putstr
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#endif
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#define FLUSH(x,y) { \
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int foo = (*x->gz_output)(x->gz_private,x->gz_slide,y); \
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if (foo) \
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return foo; \
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}
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static const int qflag = 0;
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#ifndef _KERNEL /* want to use this file in kzip also */
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extern unsigned char *kzipmalloc (int);
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extern void kzipfree (void*);
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#define malloc(x, y, z) kzipmalloc((x))
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#define free(x, y) kzipfree((x))
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#endif
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/*
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* This came from unzip-5.12. I have changed it the flow to pass
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* a structure pointer around, thus hopefully making it re-entrant.
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* Poul-Henning
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*/
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/* inflate.c -- put in the public domain by Mark Adler
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version c14o, 23 August 1994 */
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/* You can do whatever you like with this source file, though I would
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prefer that if you modify it and redistribute it that you include
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comments to that effect with your name and the date. Thank you.
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History:
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vers date who what
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---- --------- -------------- ------------------------------------
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a ~~ Feb 92 M. Adler used full (large, one-step) lookup table
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b1 21 Mar 92 M. Adler first version with partial lookup tables
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b2 21 Mar 92 M. Adler fixed bug in fixed-code blocks
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b3 22 Mar 92 M. Adler sped up match copies, cleaned up some
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b4 25 Mar 92 M. Adler added prototypes; removed window[] (now
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is the responsibility of unzip.h--also
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changed name to slide[]), so needs diffs
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for unzip.c and unzip.h (this allows
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compiling in the small model on MSDOS);
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fixed cast of q in huft_build();
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b5 26 Mar 92 M. Adler got rid of unintended macro recursion.
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b6 27 Mar 92 M. Adler got rid of nextbyte() routine. fixed
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bug in inflate_fixed().
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c1 30 Mar 92 M. Adler removed lbits, dbits environment variables.
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changed BMAX to 16 for explode. Removed
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OUTB usage, and replaced it with flush()--
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this was a 20% speed improvement! Added
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an explode.c (to replace unimplod.c) that
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uses the huft routines here. Removed
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register union.
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c2 4 Apr 92 M. Adler fixed bug for file sizes a multiple of 32k.
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c3 10 Apr 92 M. Adler reduced memory of code tables made by
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huft_build significantly (factor of two to
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three).
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c4 15 Apr 92 M. Adler added NOMEMCPY do kill use of memcpy().
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worked around a Turbo C optimization bug.
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c5 21 Apr 92 M. Adler added the GZ_WSIZE #define to allow reducing
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the 32K window size for specialized
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applications.
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c6 31 May 92 M. Adler added some typecasts to eliminate warnings
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c7 27 Jun 92 G. Roelofs added some more typecasts (444: MSC bug).
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c8 5 Oct 92 J-l. Gailly added ifdef'd code to deal with PKZIP bug.
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c9 9 Oct 92 M. Adler removed a memory error message (~line 416).
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c10 17 Oct 92 G. Roelofs changed ULONG/UWORD/byte to ulg/ush/uch,
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removed old inflate, renamed inflate_entry
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to inflate, added Mark's fix to a comment.
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c10.5 14 Dec 92 M. Adler fix up error messages for incomplete trees.
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c11 2 Jan 93 M. Adler fixed bug in detection of incomplete
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tables, and removed assumption that EOB is
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the longest code (bad assumption).
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c12 3 Jan 93 M. Adler make tables for fixed blocks only once.
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c13 5 Jan 93 M. Adler allow all zero length codes (pkzip 2.04c
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outputs one zero length code for an empty
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distance tree).
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c14 12 Mar 93 M. Adler made inflate.c standalone with the
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introduction of inflate.h.
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c14b 16 Jul 93 G. Roelofs added (unsigned) typecast to w at 470.
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c14c 19 Jul 93 J. Bush changed v[N_MAX], l[288], ll[28x+3x] arrays
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to static for Amiga.
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c14d 13 Aug 93 J-l. Gailly de-complicatified Mark's c[*p++]++ thing.
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c14e 8 Oct 93 G. Roelofs changed memset() to memzero().
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c14f 22 Oct 93 G. Roelofs renamed quietflg to qflag; made Trace()
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conditional; added inflate_free().
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c14g 28 Oct 93 G. Roelofs changed l/(lx+1) macro to pointer (Cray bug)
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c14h 7 Dec 93 C. Ghisler huft_build() optimizations.
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c14i 9 Jan 94 A. Verheijen set fixed_t{d,l} to NULL after freeing;
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G. Roelofs check NEXTBYTE macro for GZ_EOF.
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c14j 23 Jan 94 G. Roelofs removed Ghisler "optimizations"; ifdef'd
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GZ_EOF check.
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c14k 27 Feb 94 G. Roelofs added some typecasts to avoid warnings.
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c14l 9 Apr 94 G. Roelofs fixed split comments on preprocessor lines
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to avoid bug in Encore compiler.
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c14m 7 Jul 94 P. Kienitz modified to allow assembler version of
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inflate_codes() (define ASM_INFLATECODES)
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c14n 22 Jul 94 G. Roelofs changed fprintf to FPRINTF for DLL versions
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c14o 23 Aug 94 C. Spieler added a newline to a debug statement;
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G. Roelofs added another typecast to avoid MSC warning
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*/
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/*
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Inflate deflated (PKZIP's method 8 compressed) data. The compression
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method searches for as much of the current string of bytes (up to a
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length of 258) in the previous 32K bytes. If it doesn't find any
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matches (of at least length 3), it codes the next byte. Otherwise, it
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codes the length of the matched string and its distance backwards from
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the current position. There is a single Huffman code that codes both
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single bytes (called "literals") and match lengths. A second Huffman
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code codes the distance information, which follows a length code. Each
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length or distance code actually represents a base value and a number
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of "extra" (sometimes zero) bits to get to add to the base value. At
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the end of each deflated block is a special end-of-block (EOB) literal/
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length code. The decoding process is basically: get a literal/length
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code; if EOB then done; if a literal, emit the decoded byte; if a
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length then get the distance and emit the referred-to bytes from the
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sliding window of previously emitted data.
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There are (currently) three kinds of inflate blocks: stored, fixed, and
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dynamic. The compressor outputs a chunk of data at a time and decides
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which method to use on a chunk-by-chunk basis. A chunk might typically
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be 32K to 64K, uncompressed. If the chunk is uncompressible, then the
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"stored" method is used. In this case, the bytes are simply stored as
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is, eight bits per byte, with none of the above coding. The bytes are
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preceded by a count, since there is no longer an EOB code.
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If the data is compressible, then either the fixed or dynamic methods
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are used. In the dynamic method, the compressed data is preceded by
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an encoding of the literal/length and distance Huffman codes that are
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to be used to decode this block. The representation is itself Huffman
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coded, and so is preceded by a description of that code. These code
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descriptions take up a little space, and so for small blocks, there is
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a predefined set of codes, called the fixed codes. The fixed method is
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used if the block ends up smaller that way (usually for quite small
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chunks); otherwise the dynamic method is used. In the latter case, the
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codes are customized to the probabilities in the current block and so
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can code it much better than the pre-determined fixed codes can.
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The Huffman codes themselves are decoded using a mutli-level table
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lookup, in order to maximize the speed of decoding plus the speed of
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building the decoding tables. See the comments below that precede the
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lbits and dbits tuning parameters.
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*/
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/*
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Notes beyond the 1.93a appnote.txt:
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1. Distance pointers never point before the beginning of the output
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stream.
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2. Distance pointers can point back across blocks, up to 32k away.
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3. There is an implied maximum of 7 bits for the bit length table and
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15 bits for the actual data.
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4. If only one code exists, then it is encoded using one bit. (Zero
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would be more efficient, but perhaps a little confusing.) If two
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codes exist, they are coded using one bit each (0 and 1).
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5. There is no way of sending zero distance codes--a dummy must be
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sent if there are none. (History: a pre 2.0 version of PKZIP would
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store blocks with no distance codes, but this was discovered to be
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too harsh a criterion.) Valid only for 1.93a. 2.04c does allow
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zero distance codes, which is sent as one code of zero bits in
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length.
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6. There are up to 286 literal/length codes. Code 256 represents the
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end-of-block. Note however that the static length tree defines
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288 codes just to fill out the Huffman codes. Codes 286 and 287
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cannot be used though, since there is no length base or extra bits
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defined for them. Similarily, there are up to 30 distance codes.
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However, static trees define 32 codes (all 5 bits) to fill out the
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Huffman codes, but the last two had better not show up in the data.
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7. Unzip can check dynamic Huffman blocks for complete code sets.
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The exception is that a single code would not be complete (see #4).
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8. The five bits following the block type is really the number of
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literal codes sent minus 257.
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9. Length codes 8,16,16 are interpreted as 13 length codes of 8 bits
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(1+6+6). Therefore, to output three times the length, you output
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three codes (1+1+1), whereas to output four times the same length,
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you only need two codes (1+3). Hmm.
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10. In the tree reconstruction algorithm, Code = Code + Increment
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only if BitLength(i) is not zero. (Pretty obvious.)
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11. Correction: 4 Bits: # of Bit Length codes - 4 (4 - 19)
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12. Note: length code 284 can represent 227-258, but length code 285
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really is 258. The last length deserves its own, short code
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since it gets used a lot in very redundant files. The length
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258 is special since 258 - 3 (the min match length) is 255.
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13. The literal/length and distance code bit lengths are read as a
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single stream of lengths. It is possible (and advantageous) for
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a repeat code (16, 17, or 18) to go across the boundary between
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the two sets of lengths.
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*/
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#define PKZIP_BUG_WORKAROUND /* PKZIP 1.93a problem--live with it */
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/*
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inflate.h must supply the uch slide[GZ_WSIZE] array and the NEXTBYTE,
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FLUSH() and memzero macros. If the window size is not 32K, it
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should also define GZ_WSIZE. If INFMOD is defined, it can include
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compiled functions to support the NEXTBYTE and/or FLUSH() macros.
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There are defaults for NEXTBYTE and FLUSH() below for use as
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examples of what those functions need to do. Normally, you would
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also want FLUSH() to compute a crc on the data. inflate.h also
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needs to provide these typedefs:
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typedef unsigned char uch;
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typedef unsigned short ush;
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typedef unsigned long ulg;
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This module uses the external functions malloc() and free() (and
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probably memset() or bzero() in the memzero() macro). Their
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prototypes are normally found in <string.h> and <stdlib.h>.
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*/
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#define INFMOD /* tell inflate.h to include code to be
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* compiled */
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/* Huffman code lookup table entry--this entry is four bytes for machines
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that have 16-bit pointers (e.g. PC's in the small or medium model).
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Valid extra bits are 0..13. e == 15 is EOB (end of block), e == 16
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means that v is a literal, 16 < e < 32 means that v is a pointer to
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the next table, which codes e - 16 bits, and lastly e == 99 indicates
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an unused code. If a code with e == 99 is looked up, this implies an
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error in the data. */
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struct huft {
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uch e; /* number of extra bits or operation */
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uch b; /* number of bits in this code or subcode */
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union {
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ush n; /* literal, length base, or distance
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* base */
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struct huft *t; /* pointer to next level of table */
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} v;
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};
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/* Function prototypes */
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static int huft_build(struct inflate *, unsigned *, unsigned, unsigned, const ush *, const ush *, struct huft **, int *);
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static int huft_free(struct inflate *, struct huft *);
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static int inflate_codes(struct inflate *, struct huft *, struct huft *, int, int);
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static int inflate_stored(struct inflate *);
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static int xinflate(struct inflate *);
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static int inflate_fixed(struct inflate *);
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static int inflate_dynamic(struct inflate *);
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static int inflate_block(struct inflate *, int *);
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/* The inflate algorithm uses a sliding 32K byte window on the uncompressed
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stream to find repeated byte strings. This is implemented here as a
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circular buffer. The index is updated simply by incrementing and then
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and'ing with 0x7fff (32K-1). */
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/* It is left to other modules to supply the 32K area. It is assumed
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to be usable as if it were declared "uch slide[32768];" or as just
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"uch *slide;" and then malloc'ed in the latter case. The definition
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must be in unzip.h, included above. */
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/* Tables for deflate from PKZIP's appnote.txt. */
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/* Order of the bit length code lengths */
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static const unsigned border[] = {
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16, 17, 18, 0, 8, 7, 9, 6, 10, 5, 11, 4, 12, 3, 13, 2, 14, 1, 15};
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static const ush cplens[] = { /* Copy lengths for literal codes 257..285 */
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3, 4, 5, 6, 7, 8, 9, 10, 11, 13, 15, 17, 19, 23, 27, 31,
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35, 43, 51, 59, 67, 83, 99, 115, 131, 163, 195, 227, 258, 0, 0};
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/* note: see note #13 above about the 258 in this list. */
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static const ush cplext[] = { /* Extra bits for literal codes 257..285 */
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0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 2, 2, 2, 2,
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3, 3, 3, 3, 4, 4, 4, 4, 5, 5, 5, 5, 0, 99, 99}; /* 99==invalid */
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static const ush cpdist[] = { /* Copy offsets for distance codes 0..29 */
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1, 2, 3, 4, 5, 7, 9, 13, 17, 25, 33, 49, 65, 97, 129, 193,
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257, 385, 513, 769, 1025, 1537, 2049, 3073, 4097, 6145,
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8193, 12289, 16385, 24577};
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static const ush cpdext[] = { /* Extra bits for distance codes */
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0, 0, 0, 0, 1, 1, 2, 2, 3, 3, 4, 4, 5, 5, 6, 6,
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7, 7, 8, 8, 9, 9, 10, 10, 11, 11,
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12, 12, 13, 13};
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/* And'ing with mask[n] masks the lower n bits */
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static const ush mask[] = {
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0x0000,
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0x0001, 0x0003, 0x0007, 0x000f, 0x001f, 0x003f, 0x007f, 0x00ff,
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0x01ff, 0x03ff, 0x07ff, 0x0fff, 0x1fff, 0x3fff, 0x7fff, 0xffff
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};
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/* Macros for inflate() bit peeking and grabbing.
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The usage is:
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NEEDBITS(glbl,j)
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x = b & mask[j];
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DUMPBITS(j)
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where NEEDBITS makes sure that b has at least j bits in it, and
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DUMPBITS removes the bits from b. The macros use the variable k
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for the number of bits in b. Normally, b and k are register
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variables for speed, and are initialized at the begining of a
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routine that uses these macros from a global bit buffer and count.
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In order to not ask for more bits than there are in the compressed
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stream, the Huffman tables are constructed to only ask for just
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enough bits to make up the end-of-block code (value 256). Then no
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bytes need to be "returned" to the buffer at the end of the last
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block. See the huft_build() routine.
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*/
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/*
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* The following 2 were global variables.
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* They are now fields of the inflate structure.
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*/
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#define NEEDBITS(glbl,n) { \
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while(k<(n)) { \
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int c=(*glbl->gz_input)(glbl->gz_private); \
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if(c==GZ_EOF) \
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return 1; \
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b|=((ulg)c)<<k; \
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k+=8; \
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} \
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}
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#define DUMPBITS(n) {b>>=(n);k-=(n);}
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/*
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Huffman code decoding is performed using a multi-level table lookup.
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The fastest way to decode is to simply build a lookup table whose
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size is determined by the longest code. However, the time it takes
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to build this table can also be a factor if the data being decoded
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is not very long. The most common codes are necessarily the
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shortest codes, so those codes dominate the decoding time, and hence
|
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the speed. The idea is you can have a shorter table that decodes the
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shorter, more probable codes, and then point to subsidiary tables for
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the longer codes. The time it costs to decode the longer codes is
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then traded against the time it takes to make longer tables.
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This results of this trade are in the variables lbits and dbits
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below. lbits is the number of bits the first level table for literal/
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|
length codes can decode in one step, and dbits is the same thing for
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the distance codes. Subsequent tables are also less than or equal to
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those sizes. These values may be adjusted either when all of the
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codes are shorter than that, in which case the longest code length in
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bits is used, or when the shortest code is *longer* than the requested
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table size, in which case the length of the shortest code in bits is
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used.
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There are two different values for the two tables, since they code a
|
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different number of possibilities each. The literal/length table
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codes 286 possible values, or in a flat code, a little over eight
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bits. The distance table codes 30 possible values, or a little less
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than five bits, flat. The optimum values for speed end up being
|
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about one bit more than those, so lbits is 8+1 and dbits is 5+1.
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The optimum values may differ though from machine to machine, and
|
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possibly even between compilers. Your mileage may vary.
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*/
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static const int lbits = 9; /* bits in base literal/length lookup table */
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static const int dbits = 6; /* bits in base distance lookup table */
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/* If BMAX needs to be larger than 16, then h and x[] should be ulg. */
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#define BMAX 16 /* maximum bit length of any code (16 for
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|
* explode) */
|
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#define N_MAX 288 /* maximum number of codes in any set */
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|
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/* Given a list of code lengths and a maximum table size, make a set of
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tables to decode that set of codes. Return zero on success, one if
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the given code set is incomplete (the tables are still built in this
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case), two if the input is invalid (all zero length codes or an
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oversubscribed set of lengths), and three if not enough memory.
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The code with value 256 is special, and the tables are constructed
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so that no bits beyond that code are fetched when that code is
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decoded. */
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static int
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huft_build(glbl, b, n, s, d, e, t, m)
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struct inflate *glbl;
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unsigned *b; /* code lengths in bits (all assumed <= BMAX) */
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unsigned n; /* number of codes (assumed <= N_MAX) */
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unsigned s; /* number of simple-valued codes (0..s-1) */
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const ush *d; /* list of base values for non-simple codes */
|
|
const ush *e; /* list of extra bits for non-simple codes */
|
|
struct huft **t; /* result: starting table */
|
|
int *m; /* maximum lookup bits, returns actual */
|
|
{
|
|
unsigned a; /* counter for codes of length k */
|
|
unsigned c[BMAX + 1]; /* bit length count table */
|
|
unsigned el; /* length of EOB code (value 256) */
|
|
unsigned f; /* i repeats in table every f entries */
|
|
int g; /* maximum code length */
|
|
int h; /* table level */
|
|
register unsigned i; /* counter, current code */
|
|
register unsigned j; /* counter */
|
|
register int k; /* number of bits in current code */
|
|
int lx[BMAX + 1]; /* memory for l[-1..BMAX-1] */
|
|
int *l = lx + 1; /* stack of bits per table */
|
|
register unsigned *p; /* pointer into c[], b[], or v[] */
|
|
register struct huft *q;/* points to current table */
|
|
struct huft r; /* table entry for structure assignment */
|
|
struct huft *u[BMAX];/* table stack */
|
|
unsigned v[N_MAX]; /* values in order of bit length */
|
|
register int w; /* bits before this table == (l * h) */
|
|
unsigned x[BMAX + 1]; /* bit offsets, then code stack */
|
|
unsigned *xp; /* pointer into x */
|
|
int y; /* number of dummy codes added */
|
|
unsigned z; /* number of entries in current table */
|
|
|
|
/* Generate counts for each bit length */
|
|
el = n > 256 ? b[256] : BMAX; /* set length of EOB code, if any */
|
|
#ifdef _KERNEL
|
|
memzero((char *) c, sizeof(c));
|
|
#else
|
|
for (i = 0; i < BMAX+1; i++)
|
|
c [i] = 0;
|
|
#endif
|
|
p = b;
|
|
i = n;
|
|
do {
|
|
c[*p]++;
|
|
p++; /* assume all entries <= BMAX */
|
|
} while (--i);
|
|
if (c[0] == n) { /* null input--all zero length codes */
|
|
*t = (struct huft *) NULL;
|
|
*m = 0;
|
|
return 0;
|
|
}
|
|
/* Find minimum and maximum length, bound *m by those */
|
|
for (j = 1; j <= BMAX; j++)
|
|
if (c[j])
|
|
break;
|
|
k = j; /* minimum code length */
|
|
if ((unsigned) *m < j)
|
|
*m = j;
|
|
for (i = BMAX; i; i--)
|
|
if (c[i])
|
|
break;
|
|
g = i; /* maximum code length */
|
|
if ((unsigned) *m > i)
|
|
*m = i;
|
|
|
|
/* Adjust last length count to fill out codes, if needed */
|
|
for (y = 1 << j; j < i; j++, y <<= 1)
|
|
if ((y -= c[j]) < 0)
|
|
return 2; /* bad input: more codes than bits */
|
|
if ((y -= c[i]) < 0)
|
|
return 2;
|
|
c[i] += y;
|
|
|
|
/* Generate starting offsets into the value table for each length */
|
|
x[1] = j = 0;
|
|
p = c + 1;
|
|
xp = x + 2;
|
|
while (--i) { /* note that i == g from above */
|
|
*xp++ = (j += *p++);
|
|
}
|
|
|
|
/* Make a table of values in order of bit lengths */
|
|
p = b;
|
|
i = 0;
|
|
do {
|
|
if ((j = *p++) != 0)
|
|
v[x[j]++] = i;
|
|
} while (++i < n);
|
|
|
|
/* Generate the Huffman codes and for each, make the table entries */
|
|
x[0] = i = 0; /* first Huffman code is zero */
|
|
p = v; /* grab values in bit order */
|
|
h = -1; /* no tables yet--level -1 */
|
|
w = l[-1] = 0; /* no bits decoded yet */
|
|
u[0] = (struct huft *) NULL; /* just to keep compilers happy */
|
|
q = (struct huft *) NULL; /* ditto */
|
|
z = 0; /* ditto */
|
|
|
|
/* go through the bit lengths (k already is bits in shortest code) */
|
|
for (; k <= g; k++) {
|
|
a = c[k];
|
|
while (a--) {
|
|
/*
|
|
* here i is the Huffman code of length k bits for
|
|
* value *p
|
|
*/
|
|
/* make tables up to required level */
|
|
while (k > w + l[h]) {
|
|
w += l[h++]; /* add bits already decoded */
|
|
|
|
/*
|
|
* compute minimum size table less than or
|
|
* equal to *m bits
|
|
*/
|
|
z = (z = g - w) > (unsigned) *m ? *m : z; /* upper limit */
|
|
if ((f = 1 << (j = k - w)) > a + 1) { /* try a k-w bit table *//* t
|
|
* oo few codes for k-w
|
|
* bit table */
|
|
f -= a + 1; /* deduct codes from
|
|
* patterns left */
|
|
xp = c + k;
|
|
while (++j < z) { /* try smaller tables up
|
|
* to z bits */
|
|
if ((f <<= 1) <= *++xp)
|
|
break; /* enough codes to use
|
|
* up j bits */
|
|
f -= *xp; /* else deduct codes
|
|
* from patterns */
|
|
}
|
|
}
|
|
if ((unsigned) w + j > el && (unsigned) w < el)
|
|
j = el - w; /* make EOB code end at
|
|
* table */
|
|
z = 1 << j; /* table entries for j-bit
|
|
* table */
|
|
l[h] = j; /* set table size in stack */
|
|
|
|
/* allocate and link in new table */
|
|
if ((q = (struct huft *) malloc((z + 1) * sizeof(struct huft), M_GZIP, M_WAITOK)) ==
|
|
(struct huft *) NULL) {
|
|
if (h)
|
|
huft_free(glbl, u[0]);
|
|
return 3; /* not enough memory */
|
|
}
|
|
glbl->gz_hufts += z + 1; /* track memory usage */
|
|
*t = q + 1; /* link to list for
|
|
* huft_free() */
|
|
*(t = &(q->v.t)) = (struct huft *) NULL;
|
|
u[h] = ++q; /* table starts after link */
|
|
|
|
/* connect to last table, if there is one */
|
|
if (h) {
|
|
x[h] = i; /* save pattern for
|
|
* backing up */
|
|
r.b = (uch) l[h - 1]; /* bits to dump before
|
|
* this table */
|
|
r.e = (uch) (16 + j); /* bits in this table */
|
|
r.v.t = q; /* pointer to this table */
|
|
j = (i & ((1 << w) - 1)) >> (w - l[h - 1]);
|
|
u[h - 1][j] = r; /* connect to last table */
|
|
}
|
|
}
|
|
|
|
/* set up table entry in r */
|
|
r.b = (uch) (k - w);
|
|
if (p >= v + n)
|
|
r.e = 99; /* out of values--invalid
|
|
* code */
|
|
else if (*p < s) {
|
|
r.e = (uch) (*p < 256 ? 16 : 15); /* 256 is end-of-block
|
|
* code */
|
|
r.v.n = *p++; /* simple code is just the
|
|
* value */
|
|
} else {
|
|
r.e = (uch) e[*p - s]; /* non-simple--look up
|
|
* in lists */
|
|
r.v.n = d[*p++ - s];
|
|
}
|
|
|
|
/* fill code-like entries with r */
|
|
f = 1 << (k - w);
|
|
for (j = i >> w; j < z; j += f)
|
|
q[j] = r;
|
|
|
|
/* backwards increment the k-bit code i */
|
|
for (j = 1 << (k - 1); i & j; j >>= 1)
|
|
i ^= j;
|
|
i ^= j;
|
|
|
|
/* backup over finished tables */
|
|
while ((i & ((1 << w) - 1)) != x[h])
|
|
w -= l[--h]; /* don't need to update q */
|
|
}
|
|
}
|
|
|
|
/* return actual size of base table */
|
|
*m = l[0];
|
|
|
|
/* Return true (1) if we were given an incomplete table */
|
|
return y != 0 && g != 1;
|
|
}
|
|
|
|
static int
|
|
huft_free(glbl, t)
|
|
struct inflate *glbl;
|
|
struct huft *t; /* table to free */
|
|
/* Free the malloc'ed tables built by huft_build(), which makes a linked
|
|
list of the tables it made, with the links in a dummy first entry of
|
|
each table. */
|
|
{
|
|
register struct huft *p, *q;
|
|
|
|
/* Go through linked list, freeing from the malloced (t[-1]) address. */
|
|
p = t;
|
|
while (p != (struct huft *) NULL) {
|
|
q = (--p)->v.t;
|
|
free(p, M_GZIP);
|
|
p = q;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
/* inflate (decompress) the codes in a deflated (compressed) block.
|
|
Return an error code or zero if it all goes ok. */
|
|
static int
|
|
inflate_codes(glbl, tl, td, bl, bd)
|
|
struct inflate *glbl;
|
|
struct huft *tl, *td;/* literal/length and distance decoder tables */
|
|
int bl, bd; /* number of bits decoded by tl[] and td[] */
|
|
{
|
|
register unsigned e; /* table entry flag/number of extra bits */
|
|
unsigned n, d; /* length and index for copy */
|
|
unsigned w; /* current window position */
|
|
struct huft *t; /* pointer to table entry */
|
|
unsigned ml, md; /* masks for bl and bd bits */
|
|
register ulg b; /* bit buffer */
|
|
register unsigned k; /* number of bits in bit buffer */
|
|
|
|
/* make local copies of globals */
|
|
b = glbl->gz_bb; /* initialize bit buffer */
|
|
k = glbl->gz_bk;
|
|
w = glbl->gz_wp; /* initialize window position */
|
|
|
|
/* inflate the coded data */
|
|
ml = mask[bl]; /* precompute masks for speed */
|
|
md = mask[bd];
|
|
while (1) { /* do until end of block */
|
|
NEEDBITS(glbl, (unsigned) bl)
|
|
if ((e = (t = tl + ((unsigned) b & ml))->e) > 16)
|
|
do {
|
|
if (e == 99)
|
|
return 1;
|
|
DUMPBITS(t->b)
|
|
e -= 16;
|
|
NEEDBITS(glbl, e)
|
|
} while ((e = (t = t->v.t + ((unsigned) b & mask[e]))->e) > 16);
|
|
DUMPBITS(t->b)
|
|
if (e == 16) { /* then it's a literal */
|
|
glbl->gz_slide[w++] = (uch) t->v.n;
|
|
if (w == GZ_WSIZE) {
|
|
FLUSH(glbl, w);
|
|
w = 0;
|
|
}
|
|
} else { /* it's an EOB or a length */
|
|
/* exit if end of block */
|
|
if (e == 15)
|
|
break;
|
|
|
|
/* get length of block to copy */
|
|
NEEDBITS(glbl, e)
|
|
n = t->v.n + ((unsigned) b & mask[e]);
|
|
DUMPBITS(e);
|
|
|
|
/* decode distance of block to copy */
|
|
NEEDBITS(glbl, (unsigned) bd)
|
|
if ((e = (t = td + ((unsigned) b & md))->e) > 16)
|
|
do {
|
|
if (e == 99)
|
|
return 1;
|
|
DUMPBITS(t->b)
|
|
e -= 16;
|
|
NEEDBITS(glbl, e)
|
|
} while ((e = (t = t->v.t + ((unsigned) b & mask[e]))->e) > 16);
|
|
DUMPBITS(t->b)
|
|
NEEDBITS(glbl, e)
|
|
d = w - t->v.n - ((unsigned) b & mask[e]);
|
|
DUMPBITS(e)
|
|
/* do the copy */
|
|
do {
|
|
n -= (e = (e = GZ_WSIZE - ((d &= GZ_WSIZE - 1) > w ? d : w)) > n ? n : e);
|
|
#ifndef NOMEMCPY
|
|
if (w - d >= e) { /* (this test assumes
|
|
* unsigned comparison) */
|
|
memcpy(glbl->gz_slide + w, glbl->gz_slide + d, e);
|
|
w += e;
|
|
d += e;
|
|
} else /* do it slow to avoid memcpy()
|
|
* overlap */
|
|
#endif /* !NOMEMCPY */
|
|
do {
|
|
glbl->gz_slide[w++] = glbl->gz_slide[d++];
|
|
} while (--e);
|
|
if (w == GZ_WSIZE) {
|
|
FLUSH(glbl, w);
|
|
w = 0;
|
|
}
|
|
} while (n);
|
|
}
|
|
}
|
|
|
|
/* restore the globals from the locals */
|
|
glbl->gz_wp = w; /* restore global window pointer */
|
|
glbl->gz_bb = b; /* restore global bit buffer */
|
|
glbl->gz_bk = k;
|
|
|
|
/* done */
|
|
return 0;
|
|
}
|
|
|
|
/* "decompress" an inflated type 0 (stored) block. */
|
|
static int
|
|
inflate_stored(glbl)
|
|
struct inflate *glbl;
|
|
{
|
|
unsigned n; /* number of bytes in block */
|
|
unsigned w; /* current window position */
|
|
register ulg b; /* bit buffer */
|
|
register unsigned k; /* number of bits in bit buffer */
|
|
|
|
/* make local copies of globals */
|
|
b = glbl->gz_bb; /* initialize bit buffer */
|
|
k = glbl->gz_bk;
|
|
w = glbl->gz_wp; /* initialize window position */
|
|
|
|
/* go to byte boundary */
|
|
n = k & 7;
|
|
DUMPBITS(n);
|
|
|
|
/* get the length and its complement */
|
|
NEEDBITS(glbl, 16)
|
|
n = ((unsigned) b & 0xffff);
|
|
DUMPBITS(16)
|
|
NEEDBITS(glbl, 16)
|
|
if (n != (unsigned) ((~b) & 0xffff))
|
|
return 1; /* error in compressed data */
|
|
DUMPBITS(16)
|
|
/* read and output the compressed data */
|
|
while (n--) {
|
|
NEEDBITS(glbl, 8)
|
|
glbl->gz_slide[w++] = (uch) b;
|
|
if (w == GZ_WSIZE) {
|
|
FLUSH(glbl, w);
|
|
w = 0;
|
|
}
|
|
DUMPBITS(8)
|
|
}
|
|
|
|
/* restore the globals from the locals */
|
|
glbl->gz_wp = w; /* restore global window pointer */
|
|
glbl->gz_bb = b; /* restore global bit buffer */
|
|
glbl->gz_bk = k;
|
|
return 0;
|
|
}
|
|
|
|
/* decompress an inflated type 1 (fixed Huffman codes) block. We should
|
|
either replace this with a custom decoder, or at least precompute the
|
|
Huffman tables. */
|
|
static int
|
|
inflate_fixed(glbl)
|
|
struct inflate *glbl;
|
|
{
|
|
/* if first time, set up tables for fixed blocks */
|
|
if (glbl->gz_fixed_tl == (struct huft *) NULL) {
|
|
int i; /* temporary variable */
|
|
static unsigned l[288]; /* length list for huft_build */
|
|
|
|
/* literal table */
|
|
for (i = 0; i < 144; i++)
|
|
l[i] = 8;
|
|
for (; i < 256; i++)
|
|
l[i] = 9;
|
|
for (; i < 280; i++)
|
|
l[i] = 7;
|
|
for (; i < 288; i++) /* make a complete, but wrong code
|
|
* set */
|
|
l[i] = 8;
|
|
glbl->gz_fixed_bl = 7;
|
|
if ((i = huft_build(glbl, l, 288, 257, cplens, cplext,
|
|
&glbl->gz_fixed_tl, &glbl->gz_fixed_bl)) != 0) {
|
|
glbl->gz_fixed_tl = (struct huft *) NULL;
|
|
return i;
|
|
}
|
|
/* distance table */
|
|
for (i = 0; i < 30; i++) /* make an incomplete code
|
|
* set */
|
|
l[i] = 5;
|
|
glbl->gz_fixed_bd = 5;
|
|
if ((i = huft_build(glbl, l, 30, 0, cpdist, cpdext,
|
|
&glbl->gz_fixed_td, &glbl->gz_fixed_bd)) > 1) {
|
|
huft_free(glbl, glbl->gz_fixed_tl);
|
|
glbl->gz_fixed_tl = (struct huft *) NULL;
|
|
return i;
|
|
}
|
|
}
|
|
/* decompress until an end-of-block code */
|
|
return inflate_codes(glbl, glbl->gz_fixed_tl, glbl->gz_fixed_td, glbl->gz_fixed_bl, glbl->gz_fixed_bd) != 0;
|
|
}
|
|
|
|
/* decompress an inflated type 2 (dynamic Huffman codes) block. */
|
|
static int
|
|
inflate_dynamic(glbl)
|
|
struct inflate *glbl;
|
|
{
|
|
int i; /* temporary variables */
|
|
unsigned j;
|
|
unsigned l; /* last length */
|
|
unsigned m; /* mask for bit lengths table */
|
|
unsigned n; /* number of lengths to get */
|
|
struct huft *tl; /* literal/length code table */
|
|
struct huft *td; /* distance code table */
|
|
int bl; /* lookup bits for tl */
|
|
int bd; /* lookup bits for td */
|
|
unsigned nb; /* number of bit length codes */
|
|
unsigned nl; /* number of literal/length codes */
|
|
unsigned nd; /* number of distance codes */
|
|
#ifdef PKZIP_BUG_WORKAROUND
|
|
unsigned ll[288 + 32]; /* literal/length and distance code
|
|
* lengths */
|
|
#else
|
|
unsigned ll[286 + 30]; /* literal/length and distance code
|
|
* lengths */
|
|
#endif
|
|
register ulg b; /* bit buffer */
|
|
register unsigned k; /* number of bits in bit buffer */
|
|
|
|
/* make local bit buffer */
|
|
b = glbl->gz_bb;
|
|
k = glbl->gz_bk;
|
|
|
|
/* read in table lengths */
|
|
NEEDBITS(glbl, 5)
|
|
nl = 257 + ((unsigned) b & 0x1f); /* number of
|
|
* literal/length codes */
|
|
DUMPBITS(5)
|
|
NEEDBITS(glbl, 5)
|
|
nd = 1 + ((unsigned) b & 0x1f); /* number of distance codes */
|
|
DUMPBITS(5)
|
|
NEEDBITS(glbl, 4)
|
|
nb = 4 + ((unsigned) b & 0xf); /* number of bit length codes */
|
|
DUMPBITS(4)
|
|
#ifdef PKZIP_BUG_WORKAROUND
|
|
if (nl > 288 || nd > 32)
|
|
#else
|
|
if (nl > 286 || nd > 30)
|
|
#endif
|
|
return 1; /* bad lengths */
|
|
/* read in bit-length-code lengths */
|
|
for (j = 0; j < nb; j++) {
|
|
NEEDBITS(glbl, 3)
|
|
ll[border[j]] = (unsigned) b & 7;
|
|
DUMPBITS(3)
|
|
}
|
|
for (; j < 19; j++)
|
|
ll[border[j]] = 0;
|
|
|
|
/* build decoding table for trees--single level, 7 bit lookup */
|
|
bl = 7;
|
|
if ((i = huft_build(glbl, ll, 19, 19, NULL, NULL, &tl, &bl)) != 0) {
|
|
if (i == 1)
|
|
huft_free(glbl, tl);
|
|
return i; /* incomplete code set */
|
|
}
|
|
/* read in literal and distance code lengths */
|
|
n = nl + nd;
|
|
m = mask[bl];
|
|
i = l = 0;
|
|
while ((unsigned) i < n) {
|
|
NEEDBITS(glbl, (unsigned) bl)
|
|
j = (td = tl + ((unsigned) b & m))->b;
|
|
DUMPBITS(j)
|
|
j = td->v.n;
|
|
if (j < 16) /* length of code in bits (0..15) */
|
|
ll[i++] = l = j; /* save last length in l */
|
|
else if (j == 16) { /* repeat last length 3 to 6 times */
|
|
NEEDBITS(glbl, 2)
|
|
j = 3 + ((unsigned) b & 3);
|
|
DUMPBITS(2)
|
|
if ((unsigned) i + j > n)
|
|
return 1;
|
|
while (j--)
|
|
ll[i++] = l;
|
|
} else if (j == 17) { /* 3 to 10 zero length codes */
|
|
NEEDBITS(glbl, 3)
|
|
j = 3 + ((unsigned) b & 7);
|
|
DUMPBITS(3)
|
|
if ((unsigned) i + j > n)
|
|
return 1;
|
|
while (j--)
|
|
ll[i++] = 0;
|
|
l = 0;
|
|
} else { /* j == 18: 11 to 138 zero length codes */
|
|
NEEDBITS(glbl, 7)
|
|
j = 11 + ((unsigned) b & 0x7f);
|
|
DUMPBITS(7)
|
|
if ((unsigned) i + j > n)
|
|
return 1;
|
|
while (j--)
|
|
ll[i++] = 0;
|
|
l = 0;
|
|
}
|
|
}
|
|
|
|
/* free decoding table for trees */
|
|
huft_free(glbl, tl);
|
|
|
|
/* restore the global bit buffer */
|
|
glbl->gz_bb = b;
|
|
glbl->gz_bk = k;
|
|
|
|
/* build the decoding tables for literal/length and distance codes */
|
|
bl = lbits;
|
|
i = huft_build(glbl, ll, nl, 257, cplens, cplext, &tl, &bl);
|
|
if (i != 0) {
|
|
if (i == 1 && !qflag) {
|
|
FPRINTF("(incomplete l-tree) ");
|
|
huft_free(glbl, tl);
|
|
}
|
|
return i; /* incomplete code set */
|
|
}
|
|
bd = dbits;
|
|
i = huft_build(glbl, ll + nl, nd, 0, cpdist, cpdext, &td, &bd);
|
|
if (i != 0) {
|
|
if (i == 1 && !qflag) {
|
|
FPRINTF("(incomplete d-tree) ");
|
|
#ifdef PKZIP_BUG_WORKAROUND
|
|
i = 0;
|
|
}
|
|
#else
|
|
huft_free(glbl, td);
|
|
}
|
|
huft_free(glbl, tl);
|
|
return i; /* incomplete code set */
|
|
#endif
|
|
}
|
|
/* decompress until an end-of-block code */
|
|
if (inflate_codes(glbl, tl, td, bl, bd))
|
|
return 1;
|
|
|
|
/* free the decoding tables, return */
|
|
huft_free(glbl, tl);
|
|
huft_free(glbl, td);
|
|
return 0;
|
|
}
|
|
|
|
/* decompress an inflated block */
|
|
static int
|
|
inflate_block(glbl, e)
|
|
struct inflate *glbl;
|
|
int *e; /* last block flag */
|
|
{
|
|
unsigned t; /* block type */
|
|
register ulg b; /* bit buffer */
|
|
register unsigned k; /* number of bits in bit buffer */
|
|
|
|
/* make local bit buffer */
|
|
b = glbl->gz_bb;
|
|
k = glbl->gz_bk;
|
|
|
|
/* read in last block bit */
|
|
NEEDBITS(glbl, 1)
|
|
* e = (int) b & 1;
|
|
DUMPBITS(1)
|
|
/* read in block type */
|
|
NEEDBITS(glbl, 2)
|
|
t = (unsigned) b & 3;
|
|
DUMPBITS(2)
|
|
/* restore the global bit buffer */
|
|
glbl->gz_bb = b;
|
|
glbl->gz_bk = k;
|
|
|
|
/* inflate that block type */
|
|
if (t == 2)
|
|
return inflate_dynamic(glbl);
|
|
if (t == 0)
|
|
return inflate_stored(glbl);
|
|
if (t == 1)
|
|
return inflate_fixed(glbl);
|
|
/* bad block type */
|
|
return 2;
|
|
}
|
|
|
|
|
|
|
|
/* decompress an inflated entry */
|
|
static int
|
|
xinflate(glbl)
|
|
struct inflate *glbl;
|
|
{
|
|
int e; /* last block flag */
|
|
int r; /* result code */
|
|
unsigned h; /* maximum struct huft's malloc'ed */
|
|
|
|
glbl->gz_fixed_tl = (struct huft *) NULL;
|
|
|
|
/* initialize window, bit buffer */
|
|
glbl->gz_wp = 0;
|
|
glbl->gz_bk = 0;
|
|
glbl->gz_bb = 0;
|
|
|
|
/* decompress until the last block */
|
|
h = 0;
|
|
do {
|
|
glbl->gz_hufts = 0;
|
|
if ((r = inflate_block(glbl, &e)) != 0)
|
|
return r;
|
|
if (glbl->gz_hufts > h)
|
|
h = glbl->gz_hufts;
|
|
} while (!e);
|
|
|
|
/* flush out slide */
|
|
FLUSH(glbl, glbl->gz_wp);
|
|
|
|
/* return success */
|
|
return 0;
|
|
}
|
|
|
|
/* Nobody uses this - why not? */
|
|
int
|
|
inflate(glbl)
|
|
struct inflate *glbl;
|
|
{
|
|
int i;
|
|
#ifdef _KERNEL
|
|
u_char *p = NULL;
|
|
|
|
if (!glbl->gz_slide)
|
|
p = glbl->gz_slide = malloc(GZ_WSIZE, M_GZIP, M_WAITOK);
|
|
#endif
|
|
if (!glbl->gz_slide)
|
|
#ifdef _KERNEL
|
|
return(ENOMEM);
|
|
#else
|
|
return 3; /* kzip expects 3 */
|
|
#endif
|
|
i = xinflate(glbl);
|
|
|
|
if (glbl->gz_fixed_td != (struct huft *) NULL) {
|
|
huft_free(glbl, glbl->gz_fixed_td);
|
|
glbl->gz_fixed_td = (struct huft *) NULL;
|
|
}
|
|
if (glbl->gz_fixed_tl != (struct huft *) NULL) {
|
|
huft_free(glbl, glbl->gz_fixed_tl);
|
|
glbl->gz_fixed_tl = (struct huft *) NULL;
|
|
}
|
|
#ifdef _KERNEL
|
|
if (p == glbl->gz_slide) {
|
|
free(glbl->gz_slide, M_GZIP);
|
|
glbl->gz_slide = NULL;
|
|
}
|
|
#endif
|
|
return i;
|
|
}
|
|
/* ----------------------- END INFLATE.C */
|