Archive-Unzip-Burst
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unzip-6.0/amiga/flate.a view on Meta::CPAN
DUMPBITS d0
move.b h_e(t),e
cmp.b #32,e ; is it a literal?
bne nonlit ; no
move.w h_v_n(t),d0 ; yes
IFGT SIZEOF_slide-4
lea redirslide(G),a0
ELSE
move.l redirslide(G),a0
ENDC
move.b d0,(a0,w.l) ; stick in the decoded byte
addq.l #1,w
cmp.l #WSIZE,w
blo main_loop
FLUSH w
ext.l d0 ; does a test as it casts long
bne return
moveq #0,w
bra main_loop ; break (newtop loop)
nonlit: cmp.b #31,e ; is it a length?
unzip-6.0/explode.c view on Meta::CPAN
though I would prefer that if you modify it and
redistribute it that you include comments to that effect
with your name and the date. Thank you."
History:
vers date who what
---- --------- -------------- ------------------------------------
c1 30 Mar 92 M. Adler explode that uses huft_build from inflate
(this gives over a 70% speed improvement
over the original unimplode.c, which
decoded a bit at a time)
c2 4 Apr 92 M. Adler fixed bug for file sizes a multiple of 32k.
c3 10 Apr 92 M. Adler added a little memory tracking if DEBUG
c4 11 Apr 92 M. Adler added NOMEMCPY do kill use of memcpy()
c5 21 Apr 92 M. Adler added the WSIZE #define to allow reducing
the 32K window size for specialized
applications.
c6 31 May 92 M. Adler added typecasts to eliminate some warnings
c7 27 Jun 92 G. Roelofs added more typecasts.
c8 17 Oct 92 G. Roelofs changed ULONG/UWORD/byte to ulg/ush/uch.
c9 19 Jul 93 J. Bush added more typecasts (to return values);
unzip-6.0/explode.c view on Meta::CPAN
compressed form themselves. What is sent are the lengths of the codes for
each value, which is sufficient to construct the codes. Each byte of the
code representation is the code length (the low four bits representing
1..16), and the number of values sequentially with that length (the high
four bits also representing 1..16). There are 256 literal code values (if
literals are coded), 64 length code values, and 64 distance code values,
in that order at the beginning of the compressed stream. Each set of code
values is preceded (redundantly) with a byte indicating how many bytes are
in the code description that follows, in the range 1..256.
The codes themselves are decoded using tables made by huft_build() from
the bit lengths. That routine and its comments are in the inflate.c
module.
*/
#define __EXPLODE_C /* identifies this source module */
#define UNZIP_INTERNAL
#include "unzip.h" /* must supply slide[] (uch) array and NEXTBYTE macro */
#ifndef WSIZE
# define WSIZE 0x8000 /* window size--must be a power of two, and */
unzip-6.0/explode.c view on Meta::CPAN
} while (--j);
} while (--i);
return k != n ? 4 : 0; /* should have read n of them */
}
static int explode_lit(__G__ tb, tl, td, bb, bl, bd, bdl)
__GDEF
struct huft *tb, *tl, *td; /* literal, length, and distance tables */
unsigned bb, bl, bd; /* number of bits decoded by those */
unsigned bdl; /* number of distance low bits */
/* Decompress the imploded data using coded literals and a sliding
window (of size 2^(6+bdl) bytes). */
{
zusz_t s; /* bytes to decompress */
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 mb, ml, md; /* masks for bb, bl, and bd bits */
unzip-6.0/explode.c view on Meta::CPAN
return 5;
}
return 0;
}
static int explode_nolit(__G__ tl, td, bl, bd, bdl)
__GDEF
struct huft *tl, *td; /* length and distance decoder tables */
unsigned bl, bd; /* number of bits decoded by tl[] and td[] */
unsigned bdl; /* number of distance low bits */
/* Decompress the imploded data using uncoded literals and a sliding
window (of size 2^(6+bdl) bytes). */
{
zusz_t s; /* bytes to decompress */
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 */
unzip-6.0/explode.c view on Meta::CPAN
int explode(__G)
__GDEF
/* Explode an imploded compressed stream. Based on the general purpose
bit flag, decide on coded or uncoded literals, and an 8K or 4K sliding
window. Construct the literal (if any), length, and distance codes and
the tables needed to decode them (using huft_build() from inflate.c),
and call the appropriate routine for the type of data in the remainder
of the stream. The four routines are nearly identical, differing only
in whether the literal is decoded or simply read in, and in how many
bits are read in, uncoded, for the low distance bits. */
{
unsigned r; /* return codes */
struct huft *tb; /* literal code table */
struct huft *tl; /* length code table */
struct huft *td; /* distance code table */
unsigned bb; /* bits for tb */
unsigned bl; /* bits for tl */
unsigned bd; /* bits for td */
unsigned bdl; /* number of uncoded lower distance bits */
unzip-6.0/human68k/flate.s view on Meta::CPAN
DUMPBITS d0
move.b h_e(t),e
cmp.b #32,e ; is it a literal?
bne nonlit ; no
move.w h_v_n(t),d0 ; yes
IFGT SIZEOF_slide-4
lea redirslide-X(G),a0
ELSE
move.l redirslide-X(G),a0
ENDC
move.b d0,(a0,w.l) ; stick in the decoded byte
addq.l #1,w
cmp.l #WSIZE,w
blo main_loop
FLUSH w
ext.l d0 ; does a test as it casts long
bne return
moveq #0,w
bra main_loop ; break (newtop loop)
nonlit: cmp.b #31,e ; is it a length?
unzip-6.0/inflate.c view on Meta::CPAN
length of 258) in the previous 32K bytes. If it doesn't find any
matches (of at least length 3), it codes the next byte. Otherwise, it
codes the length of the matched string and its distance backwards from
the current position. There is a single Huffman code that codes both
single bytes (called "literals") and match lengths. A second Huffman
code codes the distance information, which follows a length code. Each
length or distance code actually represents a base value and a number
of "extra" (sometimes zero) bits to get to add to the base value. At
the end of each deflated block is a special end-of-block (EOB) literal/
length code. The decoding process is basically: get a literal/length
code; if EOB then done; if a literal, emit the decoded byte; if a
length then get the distance and emit the referred-to bytes from the
sliding window of previously emitted data.
There are (currently) three kinds of inflate blocks: stored, fixed, and
dynamic. The compressor outputs a chunk of data at a time and decides
which method to use on a chunk-by-chunk basis. A chunk might typically
be 32K to 64K, uncompressed. If the chunk is uncompressible, then the
"stored" method is used. In this case, the bytes are simply stored as
is, eight bits per byte, with none of the above coding. The bytes are
preceded by a count, since there is no longer an EOB code.
unzip-6.0/inflate.c view on Meta::CPAN
an encoding of the literal/length and distance Huffman codes that are
to be used to decode this block. The representation is itself Huffman
coded, and so is preceded by a description of that code. These code
descriptions take up a little space, and so for small blocks, there is
a predefined set of codes, called the fixed codes. The fixed method is
used if the block ends up smaller that way (usually for quite small
chunks); otherwise the dynamic method is used. In the latter case, the
codes are customized to the probabilities in the current block and so
can code it much better than the pre-determined fixed codes can.
The Huffman codes themselves are decoded using a multi-level table
lookup, in order to maximize the speed of decoding plus the speed of
building the decoding tables. See the comments below that precede the
lbits and dbits tuning parameters.
GRR: return values(?)
0 OK
1 incomplete table
2 bad input
3 not enough memory
the following return codes are passed through from FLUSH() errors
unzip-6.0/inflate.c view on Meta::CPAN
# endif
#endif
#define DUMPBITS(n) {b>>=(n);k-=(n);}
/*
Huffman code decoding is performed using a multi-level table lookup.
The fastest way to decode is to simply build a lookup table whose
size is determined by the longest code. However, the time it takes
to build this table can also be a factor if the data being decoded
are not very long. The most common codes are necessarily the
shortest codes, so those codes dominate the decoding time, and hence
the speed. The idea is you can have a shorter table that decodes the
shorter, more probable codes, and then point to subsidiary tables for
the longer codes. The time it costs to decode the longer codes is
then traded against the time it takes to make longer tables.
This results of this trade are in the variables lbits and dbits
below. lbits is the number of bits the first level table for literal/
length codes can decode in one step, and dbits is the same thing for
unzip-6.0/inflate.c view on Meta::CPAN
static ZCONST unsigned lbits = 9;
/* bits in base distance lookup table */
static ZCONST unsigned dbits = 6;
#ifndef ASM_INFLATECODES
int inflate_codes(__G__ tl, td, bl, bd)
__GDEF
struct huft *tl, *td; /* literal/length and distance decoder tables */
unsigned bl, bd; /* number of bits decoded by tl[] and td[] */
/* inflate (decompress) the codes in a deflated (compressed) block.
Return an error code or zero if it all goes ok. */
{
register unsigned e; /* table entry flag/number of extra bits */
unsigned d; /* index for copy */
UINT_D64 n; /* length for copy (deflate64: might be 64k+2) */
UINT_D64 w; /* current window position (deflate64: up to 64k) */
struct huft *t; /* pointer to table entry */
unsigned ml, md; /* masks for bl and bd bits */
register ulg b; /* bit buffer */
unzip-6.0/inflate.c view on Meta::CPAN
ZCONST uch *e; /* list of extra bits for non-simple codes */
struct huft **t; /* result: starting table */
unsigned *m; /* maximum lookup bits, returns actual */
/* Given a list of code lengths and a maximum table size, make a set of
tables to decode that set of codes. Return zero on success, one if
the given code set is incomplete (the tables are still built in this
case), two if the input is invalid (all zero length codes or an
oversubscribed set of lengths), and three if not enough memory.
The code with value 256 is special, and the tables are constructed
so that no bits beyond that code are fetched when that code is
decoded. */
{
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 */
unzip-6.0/inflate.c view on Meta::CPAN
if ((j = *p++) != 0)
v[x[j]++] = i;
} while (++i < n);
n = x[g]; /* set n to length of v */
/* 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) > *m ? *m : z; /* upper limit */
if ((f = 1 << (j = k - w)) > a + 1) /* try a k-w bit table */
{ /* too 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)
unzip-6.0/macos/HISTORY.TXT view on Meta::CPAN
4) CHG: {Unzip} changed the method to move extra-field data to
the internal extra-structure.
Old method was just BlockMove of the ef_structptr to ef_memptr.
This method was dangerous because not all members of the
structure seamless aligned. There are may be some fill
bytes in the structure depending on the compiler setting.
5) ADD: {Unzip} added a warning if unzipping a ZipIt/PKZip archive.
ZipIt/PKZip archives are usually additionally coded somehow.
InfoZip's Unzip will *not* decode the files. So extracted
files are may be not decoded. (see also 6. and 7.)
6) ADD: ZipIt (the Shareware Tool) has now a new extra-field signature:
0x2705. Found in "ZipIt 1.3.8". I added a new macro: EF_ZIPIT2
7) ADD: Added PKWare's extra-field signature: 0xCF77.
Found in "PKZIP v2.03". I added a new macro: EF_PKMAC
8) ADD: {console} It's now possible to save all screen outputs
to the disk.
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