* optimize slowdown problems on longest_match func detect.
[not found] <398a079a.72688d53.4aa9234e.eb039@o2.pl>
@ 2009-09-11 18:58 ` Bernd Roesch
0 siblings, 0 replies; only message in thread
From: Bernd Roesch @ 2009-09-11 18:58 UTC (permalink / raw)
To: gcc
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Hello
longest_match is a function that is used in compression to find out same
bytes.
I notice GCC 4.5.0(but on GGC series 4 happen too) use 0x64 bytes from stack
gcc3.4.0 only 8.
gcc4.5.0 is btw faster as 4.4.1.
Can somebody tell me, how this optimization can switch off in GCC ?.
GCC4.5.0 move data on this 0x64 bytes in this function.gcc3.4 do this not
and the asm optimized version of longest_match do this too not.I also dont
understand wy there must data copy.this func only compare data as far i see
and return length of same values.
here is this function optimized in asm and X86 asm
http://hermes.ibert.com/source/foreign/gzip/match.s
this stack usage happen when i use -O1.
So i can see if it run faster then.
I think thats not only a backend problem, and happen on all platforms.
Here is C source and below is asm Output from gcc 4.5.0 and GCC 3.4.0 in 68k
asm.
its compile with -g2 there are stabd in.To see what sourceline it is, look
in attached file.
uInt longest_match(s, cur_match)
deflate_state *s;
IPos cur_match; /* current match */
{
unsigned chain_length = s->max_chain_length;/* max hash chain length */
register Bytef *scan = s->window + s->strstart; /* current string */
register Bytef *match; /* matched string */
register int len; /* length of current match
*/
int best_len = s->prev_length; /* best match length so far
*/
int nice_match = s->nice_match; /* stop if match long enough
*/
IPos limit = s->strstart > (IPos)MAX_DIST(s) ?
s->strstart - (IPos)MAX_DIST(s) : NIL;
/* Stop when cur_match becomes <= limit. To simplify the code,
* we prevent matches with the string of window index 0.
*/
Posf *prev = s->prev;
uInt wmask = s->w_mask;
#ifdef UNALIGNED_OK
/* Compare two bytes at a time. Note: this is not always beneficial.
* Try with and without -DUNALIGNED_OK to check.
*/
register Bytef *strend = s->window + s->strstart + MAX_MATCH - 1;
register ush scan_start = *(ushf*)scan;
register ush scan_end = *(ushf*)(scan+best_len-1);
#else
register Bytef *strend = s->window + s->strstart + MAX_MATCH;
register Byte scan_end1 = scan[best_len-1];
register Byte scan_end = scan[best_len];
#endif
/* The code is optimized for HASH_BITS >= 8 and MAX_MATCH-2 multiple of
16.
* It is easy to get rid of this optimization if necessary.
*/
Assert(s->hash_bits >= 8 && MAX_MATCH == 258, "Code too clever");
/* Do not waste too much time if we already have a good match: */
if (s->prev_length >= s->good_match) {
chain_length >>= 2;
}
/* Do not look for matches beyond the end of the input. This is
necessary
* to make deflate deterministic.
*/
if ((uInt)nice_match > s->lookahead) nice_match = s->lookahead;
Assert((ulg)s->strstart <= s->window_size-MIN_LOOKAHEAD, "need
lookahead");
do {
Assert(cur_match < s->strstart, "no future");
match = s->window + cur_match;
/* Skip to next match if the match length cannot increase
* or if the match length is less than 2. Note that the checks
below
* for insufficient lookahead only occur occasionally for
performance
* reasons. Therefore uninitialized memory will be accessed, and
* conditional jumps will be made that depend on those values.
* However the length of the match is limited to the lookahead, so
* the output of deflate is not affected by the uninitialized
values.
*/
#if (defined(UNALIGNED_OK) && MAX_MATCH == 258)
/* This code assumes sizeof(unsigned short) == 2. Do not use
* UNALIGNED_OK if your compiler uses a different size.
*/
if (*(ushf*)(match+best_len-1) != scan_end ||
*(ushf*)match != scan_start) continue;
/* It is not necessary to compare scan[2] and match[2] since they
are
* always equal when the other bytes match, given that the hash keys
* are equal and that HASH_BITS >= 8. Compare 2 bytes at a time at
* strstart+3, +5, ... up to strstart+257. We check for insufficient
* lookahead only every 4th comparison; the 128th check will be made
* at strstart+257. If MAX_MATCH-2 is not a multiple of 8, it is
* necessary to put more guard bytes at the end of the window, or
* to check more often for insufficient lookahead.
*/
Assert(scan[2] == match[2], "scan[2]?");
scan++, match++;
do {
} while (*(ushf*)(scan+=2) == *(ushf*)(match+=2) &&
*(ushf*)(scan+=2) == *(ushf*)(match+=2) &&
*(ushf*)(scan+=2) == *(ushf*)(match+=2) &&
*(ushf*)(scan+=2) == *(ushf*)(match+=2) &&
scan < strend);
/* The funny "do {}" generates better code on most compilers */
/* Here, scan <= window+strstart+257 */
Assert(scan <= s->window+(unsigned)(s->window_size-1), "wild scan");
if (*scan == *match) scan++;
len = (MAX_MATCH - 1) - (int)(strend-scan);
scan = strend - (MAX_MATCH-1);
#else /* UNALIGNED_OK */
if (match[best_len] != scan_end ||
match[best_len-1] != scan_end1 ||
*match != *scan ||
*++match != scan[1]) continue;
/* The check at best_len-1 can be removed because it will be made
* again later. (This heuristic is not always a win.)
* It is not necessary to compare scan[2] and match[2] since they
* are always equal when the other bytes match, given that
* the hash keys are equal and that HASH_BITS >= 8.
*/
scan += 2, match++;
Assert(*scan == *match, "match[2]?");
/* We check for insufficient lookahead only every 8th comparison;
* the 256th check will be made at strstart+258.
*/
do {
} while (*++scan == *++match && *++scan == *++match &&
*++scan == *++match && *++scan == *++match &&
*++scan == *++match && *++scan == *++match &&
*++scan == *++match && *++scan == *++match &&
scan < strend);
Assert(scan <= s->window+(unsigned)(s->window_size-1), "wild scan");
len = MAX_MATCH - (int)(strend - scan);
scan = strend - MAX_MATCH;
#endif /* UNALIGNED_OK */
if (len > best_len) {
s->match_start = cur_match;
best_len = len;
if (len >= nice_match) break;
#ifdef UNALIGNED_OK
scan_end = *(ushf*)(scan+best_len-1);
#else
scan_end1 = scan[best_len-1];
scan_end = scan[best_len];
#endif
}
} while ((cur_match = prev[cur_match & wmask]) > limit
&& --chain_length != 0);
if ((uInt)best_len <= s->lookahead) return (uInt)best_len;
return s->lookahead;
}
#endif /* ASMV */
#endif /* FASTEST */
GCC 4.5.0
_longest_match:
.stabd 68,0,1069
LFBB1:
lea (-64,sp),sp
movem.l #16190,-(sp)
move.l 112(sp),a1
move.l 116(sp),d1
.stabd 68,0,1070
move.l 122(a1),d2
.stabd 68,0,1071
move.l 54(a1),a2
move.l 106(a1),d3
lea (a2,d3.l),a4
.stabd 68,0,1075
move.l 118(a1),d0
move.l d0,d7
.stabd 68,0,1076
move.l 142(a1),a6
.stabd 68,0,1077
move.l 42(a1),d5
.stabd 68,0,1078
move.l d5,d4
add.l #-262,d4
cmp.l d3,d4
jcc L12
move.l d3,d4
add.l #262,d4
sub.l d5,d4
L2:
.stabd 68,0,1082
move.l 62(a1),a3
.stabd 68,0,1083
move.l 50(a1),d5
.stabd 68,0,1093
lea 258(a2,d3.l),a5
.stabd 68,0,1094
move.b -1(a4,d0.l),50(sp)
.stabd 68,0,1095
move.b (a4,d0.l),d3
.stabd 68,0,1101
cmp.l 138(a1),d0
jcs L3
.stabd 68,0,1106
lsr.l #2,d2
L3:
.stabd 68,0,1111
move.l 114(a1),d6
cmp.l a6,d6
jcc L10
move.l d6,a6
L10:
.stabd 68,0,1188
move.l #258,d0
sub.l a5,d0
move.l d0,62(sp)
.stabd 68,0,1189
lea (-258,a5),a0
move.l a0,58(sp)
move.l d7,a0
move.l a1,66(sp)
move.l d6,54(sp)
move.l a6,46(sp)
move.l a5,a6
move.w d3,a5
L25:
.stabd 68,0,1117
lea (a2,d1.l),a1
.stabd 68,0,1162
move.l a0,d0
move.b (a1,a0.l),d3
move.w a5,d6
cmp.b d3,d6
jeq L29
L5:
.stabd 68,0,1204
and.l d5,d1
.stabd 68,0,1205
move.w (a3,d1.l*2),d1
and.l #65535,d1
cmp.l d4,d1
jls L27
subq.l #1,d2
jne L25
L27:
move.l 54(sp),d6
L9:
.stabd 68,0,1207
cmp.l d0,d6
jcc L11
move.l d6,d0
L11:
.stabd 68,0,1209
movem.l (sp)+,#31996
lea (64,sp),sp
rts
L29:
.stabd 68,0,1163
move.b -1(a1,a0.l),d7
.stabd 68,0,1162
cmp.b 50(sp),d7
jne L5
.stabd 68,0,1164
move.b (a1),d6
cmp.b (a4),d6
jne L5
addq.l #1,a1
.stabd 68,0,1165
move.b (a1),d6
cmp.b 1(a4),d6
jne L5
.stabd 68,0,1173
lea (2,a4),a5
move.l a1,d6
addq.l #1,d6
lea (3,a4),a1
move.l a1,84(sp)
lea (9,a4),a1
move.l a1,88(sp)
lea (8,a4),a1
move.l a1,92(sp)
lea (7,a4),a1
move.l a1,96(sp)
lea (6,a4),a1
move.l a1,100(sp)
lea (5,a4),a1
move.l a1,104(sp)
addq.l #4,a4
move.l d6,a1
move.l 46(sp),d6
move.l d5,50(sp)
move.l a0,d5
move.l a0,70(sp)
move.l 88(sp),d0
move.b d3,74(sp)
move.l d2,88(sp)
move.l a6,d2
move.b d7,75(sp)
move.l a3,d7
move.l 100(sp),a6
move.l 104(sp),a0
move.l d1,76(sp)
move.l 92(sp),d1
move.l a2,80(sp)
move.l a4,a2
move.l 84(sp),a4
L7:
.stabd 68,0,1180
move.b (a4),d3
cmp.b 1(a1),d3
jne L16
move.b (a2),d3
cmp.b 2(a1),d3
jne L17
.stabd 68,0,1181
move.b (a0),d3
cmp.b 3(a1),d3
jne L18
move.b (a6),d3
cmp.b 4(a1),d3
jne L19
.stabd 68,0,1182
move.l 96(sp),a3
move.b (a3),d3
cmp.b 5(a1),d3
jne L20
move.l d1,a3
move.b (a3),d3
cmp.b 6(a1),d3
jne L21
.stabd 68,0,1183
move.l d0,a3
move.b (a3),d3
cmp.b 7(a1),d3
jne L22
.stabd 68,0,1066
addq.l #8,a5
addq.l #8,a1
.stabd 68,0,1183
move.b (a5),d3
cmp.b (a1),d3
jne L26
addq.l #8,a4
addq.l #8,d0
addq.l #8,d1
addq.l #8,96(sp)
addq.l #8,a6
addq.l #8,a0
addq.l #8,a2
cmp.l d2,a5
jcs L7
L26:
move.l d5,a0
move.l d6,46(sp)
move.l d7,a3
move.l 50(sp),d5
move.l d2,a6
move.l 88(sp),d2
move.l 70(sp),d0
move.b 74(sp),d3
move.b 75(sp),d7
move.l 76(sp),d1
move.l 80(sp),a2
L6:
.stabd 68,0,1188
add.l 62(sp),a5
.stabd 68,0,1189
move.l 58(sp),a4
.stabd 68,0,1193
cmp.l a0,a5
jle L23
.stabd 68,0,1194
move.l 66(sp),a0
move.l d1,110(a0)
.stabd 68,0,1196
cmp.l 46(sp),a5
jge L30
.stabd 68,0,1200
move.l a5,d0
move.l 58(sp),a1
move.b -1(a1,a5.l),50(sp)
.stabd 68,0,1201
move.b (a1,a5.l),d3
move.w d3,a5
move.l d0,a0
jra L5
L12:
.stabd 68,0,1078
clr.l d4
jra L2
L23:
.stabd 68,0,1193
move.w d3,a5
move.b d7,50(sp)
jra L5
L16:
move.l d5,a0
move.l a4,84(sp)
move.l d6,46(sp)
move.l d7,a3
move.l 50(sp),d5
move.l d2,a6
move.l 88(sp),d2
move.l 70(sp),d0
move.b 74(sp),d3
move.b 75(sp),d7
move.l 76(sp),d1
move.l 80(sp),a2
.stabd 68,0,1184
move.l a4,a5
jra L6
L17:
move.l d5,a0
move.l d6,46(sp)
move.l d7,a3
move.l 50(sp),d5
move.l d2,a6
move.l 88(sp),d2
move.l 70(sp),d0
move.b 74(sp),d3
move.b 75(sp),d7
move.l a2,a4
move.l 76(sp),d1
move.l 80(sp),a2
.stabd 68,0,1180
move.l a4,a5
jra L6
L19:
move.l d5,a0
move.l d6,46(sp)
move.l d7,a3
move.l 50(sp),d5
move.l 70(sp),d0
move.b 75(sp),d7
move.l a6,100(sp)
move.l d2,a6
move.l 88(sp),d2
move.b 74(sp),d3
move.l 76(sp),d1
move.l 80(sp),a2
.stabd 68,0,1181
move.l 100(sp),a5
jra L6
L18:
move.l d6,46(sp)
move.l d7,a3
move.l d2,a6
move.l 88(sp),d2
move.l 70(sp),d0
move.b 74(sp),d3
move.b 75(sp),d7
move.l a0,104(sp)
move.l d5,a0
move.l 50(sp),d5
move.l 76(sp),d1
move.l 80(sp),a2
.stabd 68,0,1180
move.l 104(sp),a5
jra L6
L21:
move.l d5,a0
move.l d6,46(sp)
move.l d7,a3
move.l 50(sp),d5
move.l d2,a6
move.l 88(sp),d2
move.l 70(sp),d0
move.b 74(sp),d3
move.b 75(sp),d7
move.l d1,92(sp)
move.l 76(sp),d1
move.l 80(sp),a2
.stabd 68,0,1182
move.l 92(sp),a5
jra L6
L20:
move.l d5,a0
move.l d6,46(sp)
move.l 50(sp),d5
move.l d2,a6
move.l 88(sp),d2
move.l 70(sp),d0
move.b 74(sp),d3
move.l d7,a3
move.b 75(sp),d7
move.l 76(sp),d1
move.l 80(sp),a2
.stabd 68,0,1181
move.l 96(sp),a5
jra L6
L22:
move.l d5,a0
move.l d6,46(sp)
move.l d7,a3
move.l 50(sp),d5
move.l d2,a6
move.l 88(sp),d2
move.l d0,88(sp)
move.l 70(sp),d0
move.b 74(sp),d3
move.b 75(sp),d7
move.l 76(sp),d1
move.l 80(sp),a2
.stabd 68,0,1182
move.l 88(sp),a5
jra L6
L30:
move.l a5,d0
move.l 54(sp),d6
jra L9
.stabs "longest_match:f17",36,0,1066,_longest_match
.stabs "s:p189=*181",160,0,1067,112
.stabs "cur_match:p171",160,0,1068,116
.stabs "chain_length:r4",64,0,1070,2
.stabs "len:r1",64,0,1073,0
.stabs "best_len:r1",64,0,1075,7
.stabs "nice_match:r1",64,0,1076,14
.stabs "limit:r171",64,0,1077,4
.stabs "prev:r172",64,0,1082,11
.stabs "wmask:r17",64,0,1083,5
.stabs "strend:r127",64,0,1093,13
.stabs "s:r189",64,0,1067,9
.stabs "cur_match:r171",64,0,1068,1
.stabn 192,0,0,LFBB1
.stabn 224,0,0,Lscope1
Lscope1:
.even
---------------------- GCC 3.4.0 ----------------------------------------
.even
_longest_match:
.stabd 68,0,1069
subqw #8,sp
moveml #0x3f3e,sp@-
movel sp@(56),a4
movel sp@(60),d1
.stabd 68,0,1070
movel a4@(122),d2
.stabd 68,0,1071
movel a4@(54),a2
movel a4@(106),a1
lea a2@(0,a1:l),a3
.stabd 68,0,1075
movel a4@(118),d3
.stabd 68,0,1076
movel a4@(142),d7
.stabd 68,0,1077
movel a4@(42),a0
movel a0,d0
addl #-262,d0
lea 0:w,a6
cmpl a1,d0
jcc L378
.stabd 68,0,1077
movel a1,a5
subl a0,a5
lea a5@(262),a6
L378:
.stabd 68,0,1082
movel a4@(62),a5
.stabd 68,0,1083
movel a4@(50),d6
.stabd 68,0,1093
lea a1@(258,a2:l),a1
movel a1,sp@(48)
.stabd 68,0,1094
moveb a3@(-1,d3:l),sp@(47)
.stabd 68,0,1095
moveb a3@(d3:l),d4
.stabd 68,0,1104
cmpl a4@(138),d3
jcs L379
.stabd 68,0,1105
lsrl #2,d2
L379:
.stabd 68,0,1110
movel a4@(114),d5
cmpl d7,d5
jcc L392
movel d5,d7
.even
L392:
.stabd 68,0,1116
lea a2@(0,d1:l),a0
.stabd 68,0,1161
cmpb a0@(d3:l),d4
jeq L396
L383:
.stabd 68,0,1203
movel d1,d0
andl d6,d0
clrl d1
movew a5@(d0:l:2),d1
cmpl d1,a6
jcc L382
subql #1,d2
jne L392
L382:
.stabd 68,0,1206
movel d3,d0
cmpl d3,d5
jcc L376
.stabd 68,0,1207
movel d5,d0
jra L376
.even
L396:
.stabd 68,0,1161
moveb sp@(47),d0
cmpb a0@(-1,d3:l),d0
jne L383
moveb a0@,d0
cmpb a3@,d0
jne L383
lea a0@(1),a1
moveb a1@,d0
cmpb a3@(1),d0
jne L383
.stabd 68,0,1172
lea a3@(2),a0
addql #1,a1
L386:
.stabd 68,0,1178
addql #1,a0
addql #1,a1
moveb a0@,d0
cmpb a1@,d0
jne L387
addql #1,a0
addql #1,a1
moveb a0@,d0
cmpb a1@,d0
jne L387
addql #1,a0
addql #1,a1
moveb a0@,d0
cmpb a1@,d0
jne L387
addql #1,a0
addql #1,a1
moveb a0@,d0
cmpb a1@,d0
jne L387
addql #1,a0
addql #1,a1
moveb a0@,d0
cmpb a1@,d0
jne L387
addql #1,a0
addql #1,a1
moveb a0@,d0
cmpb a1@,d0
jne L387
addql #1,a0
addql #1,a1
moveb a0@,d0
cmpb a1@,d0
jne L387
addql #1,a0
addql #1,a1
moveb a0@,d0
cmpb a1@,d0
jne L387
cmpl sp@(48),a0
jcs L386
L387:
.stabd 68,0,1187
movel sp@(48),a1
subl a0,a1
movel #258,d0
subl a1,d0
.stabd 68,0,1188
movel sp@(48),a3
lea a3@(-258),a3
.stabd 68,0,1192
cmpl d0,d3
jge L383
.stabd 68,0,1193
movel d1,a4@(110)
.stabd 68,0,1194
movel d0,d3
.stabd 68,0,1195
cmpl d0,d7
jle L382
.stabd 68,0,1199
moveb a3@(-1,d0:l),sp@(47)
.stabd 68,0,1200
moveb a3@(d0:l),d4
jra L383
.even
L376:
moveml sp@+,#0x7cfc
addqw #8,sp
rts
.stabs "longest_match:f23",36,0,1069,_longest_match
.stabs "s:p198",160,0,1067,56
.stabs "cur_match:p176",160,0,1068,60
.stabs "chain_length:r4",64,0,1070,2
.stabs "scan:r132",64,0,1071,11
.stabs "match:r132",64,0,1072,8
.stabs "len:r1",64,0,1073,0
.stabs "best_len:r1",64,0,1075,3
.stabs "nice_match:r1",64,0,1076,7
.stabs "limit:r176",64,0,1077,14
.stabs "prev:r177",64,0,1082,13
.stabs "wmask:r23",64,0,1083,6
.stabs "strend:132",128,0,1093,48
.stabs "scan_end1:22",128,0,1094,47
.stabs "scan_end:r22",64,0,1095,4
.stabs "s:r198",64,0,1067,12
.stabs "cur_match:r176",64,0,1068,1
.even
_fill_window:
> HSMathLibs V.46.00 beta 1 (17.07.2007):
>
> * the functions "IEEEDPFloor", "IEEEDPCeil" (mathieeedoubbas.library),
> "IEEESPFloor", "IEEESPCeil" (mathieeesingbas.library and
> mathieeesingbas-Patch), "SPFloor" and "SPCeil" (mathffp.library and
> mathffp-Patch) new written
> * Bugfixing of the functions "IEEEDPPow" (mathieeedoubtrans.library),
> "IEEESPPow" (mathieeesingtrans.library), "SPCos", "SPSincos", "SPCosh",
> "SPExp" and "SPPow" (mathtrans.library)
> * changed the init-function of the mathffp-Patch and
> mathieeesingbas-Patch
> * changed the init-function of all libraries
> * revised the manual
Regards
[-- Attachment #3: deflate.c --]
[-- Type: text/plain, Size: 67126 bytes --]
/* deflate.c -- compress data using the deflation algorithm
* Copyright (C) 1995-2006 Jean-loup Gailly.
* For conditions of distribution and use, see copyright notice in zlib.h
*/
/*
* ALGORITHM
*
* The "deflation" process depends on being able to identify portions
* of the input text which are identical to earlier input (within a
* sliding window trailing behind the input currently being processed).
*
* The most straightforward technique turns out to be the fastest for
* most input files: try all possible matches and select the longest.
* The key feature of this algorithm is that insertions into the string
* dictionary are very simple and thus fast, and deletions are avoided
* completely. Insertions are performed at each input character, whereas
* string matches are performed only when the previous match ends. So it
* is preferable to spend more time in matches to allow very fast string
* insertions and avoid deletions. The matching algorithm for small
* strings is inspired from that of Rabin & Karp. A brute force approach
* is used to find longer strings when a small match has been found.
* A similar algorithm is used in comic (by Jan-Mark Wams) and freeze
* (by Leonid Broukhis).
* A previous version of this file used a more sophisticated algorithm
* (by Fiala and Greene) which is guaranteed to run in linear amortized
* time, but has a larger average cost, uses more memory and is patented.
* However the F&G algorithm may be faster for some highly redundant
* files if the parameter max_chain_length (described below) is too large.
*
* ACKNOWLEDGEMENTS
*
* The idea of lazy evaluation of matches is due to Jan-Mark Wams, and
* I found it in 'freeze' written by Leonid Broukhis.
* Thanks to many people for bug reports and testing.
*
* REFERENCES
*
* Deutsch, L.P.,"DEFLATE Compressed Data Format Specification".
* Available in http://www.ietf.org/rfc/rfc1951.txt
*
* A description of the Rabin and Karp algorithm is given in the book
* "Algorithms" by R. Sedgewick, Addison-Wesley, p252.
*
* Fiala,E.R., and Greene,D.H.
* Data Compression with Finite Windows, Comm.ACM, 32,4 (1989) 490-595
*
*/
/* @(#) $Id$ */
#include "deflate.h"
const char deflate_copyright[] =
" deflate 1.2.3.3 Copyright 1995-2006 Jean-loup Gailly ";
/*
If you use the zlib library in a product, an acknowledgment is welcome
in the documentation of your product. If for some reason you cannot
include such an acknowledgment, I would appreciate that you keep this
copyright string in the executable of your product.
*/
/* ===========================================================================
* Function prototypes.
*/
typedef enum {
need_more, /* block not completed, need more input or more output */
block_done, /* block flush performed */
finish_started, /* finish started, need only more output at next deflate */
finish_done /* finish done, accept no more input or output */
} block_state;
typedef block_state (*compress_func) OF((deflate_state *s, int flush));
/* Compression function. Returns the block state after the call. */
local void fill_window OF((deflate_state *s));
local block_state deflate_stored OF((deflate_state *s, int flush));
local block_state deflate_fast OF((deflate_state *s, int flush));
#ifndef FASTEST
local block_state deflate_slow OF((deflate_state *s, int flush));
#endif
local void lm_init OF((deflate_state *s));
local void putShortMSB OF((deflate_state *s, uInt b));
local void flush_pending OF((z_streamp strm));
local int read_buf OF((z_streamp strm, Bytef *buf, unsigned size));
#ifndef FASTEST
#ifdef ASMV
void match_init OF((void)); /* asm code initialization */
uInt longest_match OF((deflate_state *s, IPos cur_match));
#else
local uInt longest_match OF((deflate_state *s, IPos cur_match));
#endif
#endif
local uInt longest_match_fast OF((deflate_state *s, IPos cur_match));
#ifdef DEBUG
local void check_match OF((deflate_state *s, IPos start, IPos match,
int length));
#endif
/* ===========================================================================
* Local data
*/
#define NIL 0
/* Tail of hash chains */
#ifndef TOO_FAR
#define TOO_FAR 32767 /* pngcrush mod */
#endif
#ifndef TOO_FAR
# define TOO_FAR 4096
#endif
/* Matches of length 3 are discarded if their distance exceeds TOO_FAR */
#define MIN_LOOKAHEAD (MAX_MATCH+MIN_MATCH+1)
/* Minimum amount of lookahead, except at the end of the input file.
* See deflate.c for comments about the MIN_MATCH+1.
*/
/* Values for max_lazy_match, good_match and max_chain_length, depending on
* the desired pack level (0..9). The values given below have been tuned to
* exclude worst case performance for pathological files. Better values may be
* found for specific files.
*/
typedef struct config_s {
ush good_length; /* reduce lazy search above this match length */
ush max_lazy; /* do not perform lazy search above this match length */
ush nice_length; /* quit search above this match length */
ush max_chain;
compress_func func;
} config;
#ifdef FASTEST
local const config configuration_table[2] = {
/* good lazy nice chain */
/* 0 */ {0, 0, 0, 0, deflate_stored}, /* store only */
/* 1 */ {4, 4, 8, 4, deflate_fast}}; /* max speed, no lazy matches */
#else
local const config configuration_table[10] = {
/* good lazy nice chain */
/* 0 */ {0, 0, 0, 0, deflate_stored}, /* store only */
/* 1 */ {4, 4, 8, 4, deflate_fast}, /* max speed, no lazy matches */
/* 2 */ {4, 5, 16, 8, deflate_fast},
/* 3 */ {4, 6, 32, 32, deflate_fast},
/* 4 */ {4, 4, 16, 16, deflate_slow}, /* lazy matches */
/* 5 */ {8, 16, 32, 32, deflate_slow},
/* 6 */ {8, 16, 128, 128, deflate_slow},
/* 7 */ {8, 32, 128, 256, deflate_slow},
/* 8 */ {32, 128, 258, 1024, deflate_slow},
/* 9 */ {32, 258, 258, 4096, deflate_slow}}; /* max compression */
#endif
/* Note: the deflate() code requires max_lazy >= MIN_MATCH and max_chain >= 4
* For deflate_fast() (levels <= 3) good is ignored and lazy has a different
* meaning.
*/
#define EQUAL 0
/* result of memcmp for equal strings */
#ifndef NO_DUMMY_DECL
struct static_tree_desc_s {int dummy;}; /* for buggy compilers */
#endif
/* ===========================================================================
* Update a hash value with the given input byte
* IN assertion: all calls to to UPDATE_HASH are made with consecutive
* input characters, so that a running hash key can be computed from the
* previous key instead of complete recalculation each time.
*/
#define UPDATE_HASH(s,h,c) (h = (((h)<<s->hash_shift) ^ (c)) & s->hash_mask)
/* ===========================================================================
* Insert string str in the dictionary and set match_head to the previous head
* of the hash chain (the most recent string with same hash key). Return
* the previous length of the hash chain.
* If this file is compiled with -DFASTEST, the compression level is forced
* to 1, and no hash chains are maintained.
* IN assertion: all calls to to INSERT_STRING are made with consecutive
* input characters and the first MIN_MATCH bytes of str are valid
* (except for the last MIN_MATCH-1 bytes of the input file).
*/
#ifdef FASTEST
#define INSERT_STRING(s, str, match_head) \
(UPDATE_HASH(s, s->ins_h, s->window[(str) + (MIN_MATCH-1)]), \
match_head = s->head[s->ins_h], \
s->head[s->ins_h] = (Pos)(str))
#else
#define INSERT_STRING(s, str, match_head) \
(UPDATE_HASH(s, s->ins_h, s->window[(str) + (MIN_MATCH-1)]), \
match_head = s->prev[(str) & s->w_mask] = s->head[s->ins_h], \
s->head[s->ins_h] = (Pos)(str))
#endif
/* ===========================================================================
* Initialize the hash table (avoiding 64K overflow for 16 bit systems).
* prev[] will be initialized on the fly.
*/
#define CLEAR_HASH(s) \
s->head[s->hash_size-1] = NIL; \
zmemzero((Bytef *)s->head, (unsigned)(s->hash_size-1)*sizeof(*s->head));
/* ========================================================================= */
int ZEXPORT deflateInit_(strm, level, version, stream_size)
z_streamp strm;
int level;
const char *version;
int stream_size;
{
return deflateInit2_(strm, level, Z_DEFLATED, MAX_WBITS, DEF_MEM_LEVEL,
Z_DEFAULT_STRATEGY, version, stream_size);
/* To do: ignore strm->next_in if we use it as window */
}
/* ========================================================================= */
int ZEXPORT deflateInit2_(strm, level, method, windowBits, memLevel, strategy,
version, stream_size)
z_streamp strm;
int level;
int method;
int windowBits;
int memLevel;
int strategy;
const char *version;
int stream_size;
{
deflate_state *s;
int wrap = 1;
static const char my_version[] = ZLIB_VERSION;
ushf *overlay;
/* We overlay pending_buf and d_buf+l_buf. This works since the average
* output size for (length,distance) codes is <= 24 bits.
*/
if (version == Z_NULL || version[0] != my_version[0] ||
stream_size != sizeof(z_stream)) {
return Z_VERSION_ERROR;
}
if (strm == Z_NULL) return Z_STREAM_ERROR;
strm->msg = Z_NULL;
if (strm->zalloc == (alloc_func)0) {
strm->zalloc = zcalloc;
strm->opaque = (voidpf)0;
}
if (strm->zfree == (free_func)0) strm->zfree = zcfree;
#ifdef FASTEST
if (level != 0) level = 1;
#else
if (level == Z_DEFAULT_COMPRESSION) level = 6;
#endif
if (windowBits < 0) { /* suppress zlib wrapper */
wrap = 0;
windowBits = -windowBits;
}
#ifdef GZIP
else if (windowBits > 15) {
wrap = 2; /* write gzip wrapper instead */
windowBits -= 16;
}
#endif
if (memLevel < 1 || memLevel > MAX_MEM_LEVEL || method != Z_DEFLATED ||
windowBits < 8 || windowBits > 15 || level < 0 || level > 9 ||
strategy < 0 || strategy > Z_FIXED) {
return Z_STREAM_ERROR;
}
if (windowBits == 8) windowBits = 9; /* until 256-byte window bug fixed */
s = (deflate_state *) ZALLOC(strm, 1, sizeof(deflate_state));
if (s == Z_NULL) return Z_MEM_ERROR;
strm->state = (struct internal_state FAR *)s;
s->strm = strm;
s->wrap = wrap;
s->gzhead = Z_NULL;
s->w_bits = windowBits;
s->w_size = 1 << s->w_bits;
s->w_mask = s->w_size - 1;
s->hash_bits = memLevel + 7;
s->hash_size = 1 << s->hash_bits;
s->hash_mask = s->hash_size - 1;
s->hash_shift = ((s->hash_bits+MIN_MATCH-1)/MIN_MATCH);
s->window = (Bytef *) ZALLOC(strm, s->w_size, 2*sizeof(Byte));
s->prev = (Posf *) ZALLOC(strm, s->w_size, sizeof(Pos));
s->head = (Posf *) ZALLOC(strm, s->hash_size, sizeof(Pos));
s->lit_bufsize = 1 << (memLevel + 6); /* 16K elements by default */
overlay = (ushf *) ZALLOC(strm, s->lit_bufsize, sizeof(ush)+2);
s->pending_buf = (uchf *) overlay;
s->pending_buf_size = (ulg)s->lit_bufsize * (sizeof(ush)+2L);
if (s->window == Z_NULL || s->prev == Z_NULL || s->head == Z_NULL ||
s->pending_buf == Z_NULL) {
s->status = FINISH_STATE;
strm->msg = (char*)ERR_MSG(Z_MEM_ERROR);
deflateEnd (strm);
return Z_MEM_ERROR;
}
s->d_buf = overlay + s->lit_bufsize/sizeof(ush);
s->l_buf = s->pending_buf + (1+sizeof(ush))*s->lit_bufsize;
s->level = level;
s->strategy = strategy;
s->method = (Byte)method;
return deflateReset(strm);
}
/* ========================================================================= */
int ZEXPORT deflateSetDictionary (strm, dictionary, dictLength)
z_streamp strm;
const Bytef *dictionary;
uInt dictLength;
{
deflate_state *s;
uInt length = dictLength;
uInt n;
IPos hash_head = 0;
if (strm == Z_NULL || strm->state == Z_NULL || dictionary == Z_NULL ||
strm->state->wrap == 2 ||
(strm->state->wrap == 1 && strm->state->status != INIT_STATE))
return Z_STREAM_ERROR;
s = strm->state;
if (s->wrap)
strm->adler = adler32(strm->adler, dictionary, dictLength);
if (length < MIN_MATCH) return Z_OK;
if (length > MAX_DIST(s)) {
length = MAX_DIST(s);
dictionary += dictLength - length; /* use the tail of the dictionary */
}
zmemcpy(s->window, dictionary, length);
s->strstart = length;
s->block_start = (long)length;
/* Insert all strings in the hash table (except for the last two bytes).
* s->lookahead stays null, so s->ins_h will be recomputed at the next
* call of fill_window.
*/
s->ins_h = s->window[0];
UPDATE_HASH(s, s->ins_h, s->window[1]);
for (n = 0; n <= length - MIN_MATCH; n++) {
INSERT_STRING(s, n, hash_head);
}
if (hash_head) hash_head = 0; /* to make compiler happy */
return Z_OK;
}
/* ========================================================================= */
int ZEXPORT deflateReset (strm)
z_streamp strm;
{
deflate_state *s;
if (strm == Z_NULL || strm->state == Z_NULL ||
strm->zalloc == (alloc_func)0 || strm->zfree == (free_func)0) {
return Z_STREAM_ERROR;
}
strm->total_in = strm->total_out = 0;
strm->msg = Z_NULL; /* use zfree if we ever allocate msg dynamically */
strm->data_type = Z_UNKNOWN;
s = (deflate_state *)strm->state;
s->pending = 0;
s->pending_out = s->pending_buf;
if (s->wrap < 0) {
s->wrap = -s->wrap; /* was made negative by deflate(..., Z_FINISH); */
}
s->status = s->wrap ? INIT_STATE : BUSY_STATE;
strm->adler =
#ifdef GZIP
s->wrap == 2 ? crc32(0L, Z_NULL, 0) :
#endif
adler32(0L, Z_NULL, 0);
s->last_flush = Z_NO_FLUSH;
_tr_init(s);
lm_init(s);
return Z_OK;
}
/* ========================================================================= */
int ZEXPORT deflateSetHeader (strm, head)
z_streamp strm;
gz_headerp head;
{
if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR;
if (strm->state->wrap != 2) return Z_STREAM_ERROR;
strm->state->gzhead = head;
return Z_OK;
}
/* ========================================================================= */
int ZEXPORT deflatePrime (strm, bits, value)
z_streamp strm;
int bits;
int value;
{
if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR;
strm->state->bi_valid = bits;
strm->state->bi_buf = (ush)(value & ((1 << bits) - 1));
return Z_OK;
}
/* ========================================================================= */
int ZEXPORT deflateParams(strm, level, strategy)
z_streamp strm;
int level;
int strategy;
{
deflate_state *s;
compress_func func;
int err = Z_OK;
if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR;
s = strm->state;
#ifdef FASTEST
if (level != 0) level = 1;
#else
if (level == Z_DEFAULT_COMPRESSION) level = 6;
#endif
if (level < 0 || level > 9 || strategy < 0 || strategy > Z_FIXED) {
return Z_STREAM_ERROR;
}
func = configuration_table[s->level].func;
if (func != configuration_table[level].func && strm->total_in != 0) {
/* Flush the last buffer: */
err = deflate(strm, Z_PARTIAL_FLUSH);
}
if (s->level != level) {
s->level = level;
s->max_lazy_match = configuration_table[level].max_lazy;
s->good_match = configuration_table[level].good_length;
s->nice_match = configuration_table[level].nice_length;
s->max_chain_length = configuration_table[level].max_chain;
}
s->strategy = strategy;
return err;
}
/* ========================================================================= */
int ZEXPORT deflateTune(strm, good_length, max_lazy, nice_length, max_chain)
z_streamp strm;
int good_length;
int max_lazy;
int nice_length;
int max_chain;
{
deflate_state *s;
if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR;
s = strm->state;
s->good_match = good_length;
s->max_lazy_match = max_lazy;
s->nice_match = nice_length;
s->max_chain_length = max_chain;
return Z_OK;
}
/* =========================================================================
* For the default windowBits of 15 and memLevel of 8, this function returns
* a close to exact, as well as small, upper bound on the compressed size.
* They are coded as constants here for a reason--if the #define's are
* changed, then this function needs to be changed as well. The return
* value for 15 and 8 only works for those exact settings.
*
* For any setting other than those defaults for windowBits and memLevel,
* the value returned is a conservative worst case for the maximum expansion
* resulting from using fixed blocks instead of stored blocks, which deflate
* can emit on compressed data for some combinations of the parameters.
*
* This function could be more sophisticated to provide closer upper bounds for
* every combination of windowBits and memLevel. But even the conservative
* upper bound of about 14% expansion does not seem onerous for output buffer
* allocation.
*/
uLong ZEXPORT deflateBound(strm, sourceLen)
z_streamp strm;
uLong sourceLen;
{
deflate_state *s;
uLong complen, wraplen;
Bytef *str;
/* conservative upper bound for compressed data */
complen = sourceLen +
((sourceLen + 7) >> 3) + ((sourceLen + 63) >> 6) + 5;
/* if can't get parameters, return conservative bound plus zlib wrapper */
if (strm == Z_NULL || strm->state == Z_NULL)
return complen + 6;
/* compute wrapper length */
s = strm->state;
switch (s->wrap) {
case 0: /* raw deflate */
wraplen = 0;
break;
case 1: /* zlib wrapper */
wraplen = 6 + (s->strstart ? 4 : 0);
break;
case 2: /* gzip wrapper */
wraplen = 18;
if (s->gzhead != NULL) { /* user-supplied gzip header */
if (s->gzhead->extra != NULL)
wraplen += 2 + s->gzhead->extra_len;
str = s->gzhead->name;
if (str != NULL)
do {
wraplen++;
} while (*str++);
str = s->gzhead->comment;
if (str != NULL)
do {
wraplen++;
} while (*str++);
if (s->gzhead->hcrc)
wraplen += 2;
}
break;
default: /* for compiler happiness */
wraplen = 6;
}
/* if not default parameters, return conservative bound */
if (s->w_bits != 15 || s->hash_bits != 8 + 7)
return complen + wraplen;
/* default settings: return tight bound for that case */
return compressBound(sourceLen) - 6 + wraplen;
}
/* =========================================================================
* Put a short in the pending buffer. The 16-bit value is put in MSB order.
* IN assertion: the stream state is correct and there is enough room in
* pending_buf.
*/
local void putShortMSB (s, b)
deflate_state *s;
uInt b;
{
put_byte(s, (Byte)(b >> 8));
put_byte(s, (Byte)(b & 0xff));
}
/* =========================================================================
* Flush as much pending output as possible. All deflate() output goes
* through this function so some applications may wish to modify it
* to avoid allocating a large strm->next_out buffer and copying into it.
* (See also read_buf()).
*/
local void flush_pending(strm)
z_streamp strm;
{
unsigned len = strm->state->pending;
if (len > strm->avail_out) len = strm->avail_out;
if (len == 0) return;
zmemcpy(strm->next_out, strm->state->pending_out, len);
strm->next_out += len;
strm->state->pending_out += len;
strm->total_out += len;
strm->avail_out -= len;
strm->state->pending -= len;
if (strm->state->pending == 0) {
strm->state->pending_out = strm->state->pending_buf;
}
}
/* ========================================================================= */
int ZEXPORT deflate (strm, flush)
z_streamp strm;
int flush;
{
int old_flush; /* value of flush param for previous deflate call */
deflate_state *s;
if (strm == Z_NULL || strm->state == Z_NULL ||
flush > Z_FINISH || flush < 0) {
return Z_STREAM_ERROR;
}
s = strm->state;
if (strm->next_out == Z_NULL ||
(strm->next_in == Z_NULL && strm->avail_in != 0) ||
(s->status == FINISH_STATE && flush != Z_FINISH)) {
ERR_RETURN(strm, Z_STREAM_ERROR);
}
if (strm->avail_out == 0) ERR_RETURN(strm, Z_BUF_ERROR);
s->strm = strm; /* just in case */
old_flush = s->last_flush;
s->last_flush = flush;
/* Write the header */
if (s->status == INIT_STATE) {
#ifdef GZIP
if (s->wrap == 2) {
strm->adler = crc32(0L, Z_NULL, 0);
put_byte(s, 31);
put_byte(s, 139);
put_byte(s, 8);
if (s->gzhead == NULL) {
put_byte(s, 0);
put_byte(s, 0);
put_byte(s, 0);
put_byte(s, 0);
put_byte(s, 0);
put_byte(s, s->level == 9 ? 2 :
(s->strategy >= Z_HUFFMAN_ONLY || s->level < 2 ?
4 : 0));
put_byte(s, OS_CODE);
s->status = BUSY_STATE;
}
else {
put_byte(s, (s->gzhead->text ? 1 : 0) +
(s->gzhead->hcrc ? 2 : 0) +
(s->gzhead->extra == Z_NULL ? 0 : 4) +
(s->gzhead->name == Z_NULL ? 0 : 8) +
(s->gzhead->comment == Z_NULL ? 0 : 16)
);
put_byte(s, (Byte)(s->gzhead->time & 0xff));
put_byte(s, (Byte)((s->gzhead->time >> 8) & 0xff));
put_byte(s, (Byte)((s->gzhead->time >> 16) & 0xff));
put_byte(s, (Byte)((s->gzhead->time >> 24) & 0xff));
put_byte(s, s->level == 9 ? 2 :
(s->strategy >= Z_HUFFMAN_ONLY || s->level < 2 ?
4 : 0));
put_byte(s, s->gzhead->os & 0xff);
if (s->gzhead->extra != NULL) {
put_byte(s, s->gzhead->extra_len & 0xff);
put_byte(s, (s->gzhead->extra_len >> 8) & 0xff);
}
if (s->gzhead->hcrc)
strm->adler = crc32(strm->adler, s->pending_buf,
s->pending);
s->gzindex = 0;
s->status = EXTRA_STATE;
}
}
else
#endif
{
uInt header = (Z_DEFLATED + ((s->w_bits-8)<<4)) << 8;
uInt level_flags;
if (s->strategy >= Z_HUFFMAN_ONLY || s->level < 2)
level_flags = 0;
else if (s->level < 6)
level_flags = 1;
else if (s->level == 6)
level_flags = 2;
else
level_flags = 3;
header |= (level_flags << 6);
if (s->strstart != 0) header |= PRESET_DICT;
header += 31 - (header % 31);
s->status = BUSY_STATE;
putShortMSB(s, header);
/* Save the adler32 of the preset dictionary: */
if (s->strstart != 0) {
putShortMSB(s, (uInt)(strm->adler >> 16));
putShortMSB(s, (uInt)(strm->adler & 0xffff));
}
strm->adler = adler32(0L, Z_NULL, 0);
}
}
#ifdef GZIP
if (s->status == EXTRA_STATE) {
if (s->gzhead->extra != NULL) {
uInt beg = s->pending; /* start of bytes to update crc */
while (s->gzindex < (s->gzhead->extra_len & 0xffff)) {
if (s->pending == s->pending_buf_size) {
if (s->gzhead->hcrc && s->pending > beg)
strm->adler = crc32(strm->adler, s->pending_buf + beg,
s->pending - beg);
flush_pending(strm);
beg = s->pending;
if (s->pending == s->pending_buf_size)
break;
}
put_byte(s, s->gzhead->extra[s->gzindex]);
s->gzindex++;
}
if (s->gzhead->hcrc && s->pending > beg)
strm->adler = crc32(strm->adler, s->pending_buf + beg,
s->pending - beg);
if (s->gzindex == s->gzhead->extra_len) {
s->gzindex = 0;
s->status = NAME_STATE;
}
}
else
s->status = NAME_STATE;
}
if (s->status == NAME_STATE) {
if (s->gzhead->name != NULL) {
uInt beg = s->pending; /* start of bytes to update crc */
int val;
do {
if (s->pending == s->pending_buf_size) {
if (s->gzhead->hcrc && s->pending > beg)
strm->adler = crc32(strm->adler, s->pending_buf + beg,
s->pending - beg);
flush_pending(strm);
beg = s->pending;
if (s->pending == s->pending_buf_size) {
val = 1;
break;
}
}
val = s->gzhead->name[s->gzindex++];
put_byte(s, val);
} while (val != 0);
if (s->gzhead->hcrc && s->pending > beg)
strm->adler = crc32(strm->adler, s->pending_buf + beg,
s->pending - beg);
if (val == 0) {
s->gzindex = 0;
s->status = COMMENT_STATE;
}
}
else
s->status = COMMENT_STATE;
}
if (s->status == COMMENT_STATE) {
if (s->gzhead->comment != NULL) {
uInt beg = s->pending; /* start of bytes to update crc */
int val;
do {
if (s->pending == s->pending_buf_size) {
if (s->gzhead->hcrc && s->pending > beg)
strm->adler = crc32(strm->adler, s->pending_buf + beg,
s->pending - beg);
flush_pending(strm);
beg = s->pending;
if (s->pending == s->pending_buf_size) {
val = 1;
break;
}
}
val = s->gzhead->comment[s->gzindex++];
put_byte(s, val);
} while (val != 0);
if (s->gzhead->hcrc && s->pending > beg)
strm->adler = crc32(strm->adler, s->pending_buf + beg,
s->pending - beg);
if (val == 0)
s->status = HCRC_STATE;
}
else
s->status = HCRC_STATE;
}
if (s->status == HCRC_STATE) {
if (s->gzhead->hcrc) {
if (s->pending + 2 > s->pending_buf_size)
flush_pending(strm);
if (s->pending + 2 <= s->pending_buf_size) {
put_byte(s, (Byte)(strm->adler & 0xff));
put_byte(s, (Byte)((strm->adler >> 8) & 0xff));
strm->adler = crc32(0L, Z_NULL, 0);
s->status = BUSY_STATE;
}
}
else
s->status = BUSY_STATE;
}
#endif
/* Flush as much pending output as possible */
if (s->pending != 0) {
flush_pending(strm);
if (strm->avail_out == 0) {
/* Since avail_out is 0, deflate will be called again with
* more output space, but possibly with both pending and
* avail_in equal to zero. There won't be anything to do,
* but this is not an error situation so make sure we
* return OK instead of BUF_ERROR at next call of deflate:
*/
s->last_flush = -1;
return Z_OK;
}
/* Make sure there is something to do and avoid duplicate consecutive
* flushes. For repeated and useless calls with Z_FINISH, we keep
* returning Z_STREAM_END instead of Z_BUF_ERROR.
*/
} else if (strm->avail_in == 0 && flush <= old_flush &&
flush != Z_FINISH) {
ERR_RETURN(strm, Z_BUF_ERROR);
}
/* User must not provide more input after the first FINISH: */
if (s->status == FINISH_STATE && strm->avail_in != 0) {
ERR_RETURN(strm, Z_BUF_ERROR);
}
/* Start a new block or continue the current one.
*/
if (strm->avail_in != 0 || s->lookahead != 0 ||
(flush != Z_NO_FLUSH && s->status != FINISH_STATE)) {
block_state bstate;
bstate = (*(configuration_table[s->level].func))(s, flush);
if (bstate == finish_started || bstate == finish_done) {
s->status = FINISH_STATE;
}
if (bstate == need_more || bstate == finish_started) {
if (strm->avail_out == 0) {
s->last_flush = -1; /* avoid BUF_ERROR next call, see above */
}
return Z_OK;
/* If flush != Z_NO_FLUSH && avail_out == 0, the next call
* of deflate should use the same flush parameter to make sure
* that the flush is complete. So we don't have to output an
* empty block here, this will be done at next call. This also
* ensures that for a very small output buffer, we emit at most
* one empty block.
*/
}
if (bstate == block_done) {
if (flush == Z_PARTIAL_FLUSH) {
_tr_align(s);
} else { /* FULL_FLUSH or SYNC_FLUSH */
_tr_stored_block(s, (char*)0, 0L, 0);
/* For a full flush, this empty block will be recognized
* as a special marker by inflate_sync().
*/
if (flush == Z_FULL_FLUSH) {
CLEAR_HASH(s); /* forget history */
}
}
flush_pending(strm);
if (strm->avail_out == 0) {
s->last_flush = -1; /* avoid BUF_ERROR at next call, see above */
return Z_OK;
}
}
}
Assert(strm->avail_out > 0, "bug2");
if (flush != Z_FINISH) return Z_OK;
if (s->wrap <= 0) return Z_STREAM_END;
/* Write the trailer */
#ifdef GZIP
if (s->wrap == 2) {
put_byte(s, (Byte)(strm->adler & 0xff));
put_byte(s, (Byte)((strm->adler >> 8) & 0xff));
put_byte(s, (Byte)((strm->adler >> 16) & 0xff));
put_byte(s, (Byte)((strm->adler >> 24) & 0xff));
put_byte(s, (Byte)(strm->total_in & 0xff));
put_byte(s, (Byte)((strm->total_in >> 8) & 0xff));
put_byte(s, (Byte)((strm->total_in >> 16) & 0xff));
put_byte(s, (Byte)((strm->total_in >> 24) & 0xff));
}
else
#endif
{
putShortMSB(s, (uInt)(strm->adler >> 16));
putShortMSB(s, (uInt)(strm->adler & 0xffff));
}
flush_pending(strm);
/* If avail_out is zero, the application will call deflate again
* to flush the rest.
*/
if (s->wrap > 0) s->wrap = -s->wrap; /* write the trailer only once! */
return s->pending != 0 ? Z_OK : Z_STREAM_END;
}
/* ========================================================================= */
int ZEXPORT deflateEnd (strm)
z_streamp strm;
{
int status;
if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR;
status = strm->state->status;
if (status != INIT_STATE &&
status != EXTRA_STATE &&
status != NAME_STATE &&
status != COMMENT_STATE &&
status != HCRC_STATE &&
status != BUSY_STATE &&
status != FINISH_STATE) {
return Z_STREAM_ERROR;
}
/* Deallocate in reverse order of allocations: */
TRY_FREE(strm, strm->state->pending_buf);
TRY_FREE(strm, strm->state->head);
TRY_FREE(strm, strm->state->prev);
TRY_FREE(strm, strm->state->window);
ZFREE(strm, strm->state);
strm->state = Z_NULL;
return status == BUSY_STATE ? Z_DATA_ERROR : Z_OK;
}
/* =========================================================================
* Copy the source state to the destination state.
* To simplify the source, this is not supported for 16-bit MSDOS (which
* doesn't have enough memory anyway to duplicate compression states).
*/
int ZEXPORT deflateCopy (dest, source)
z_streamp dest;
z_streamp source;
{
#ifdef MAXSEG_64K
return Z_STREAM_ERROR;
#else
deflate_state *ds;
deflate_state *ss;
ushf *overlay;
if (source == Z_NULL || dest == Z_NULL || source->state == Z_NULL) {
return Z_STREAM_ERROR;
}
ss = source->state;
zmemcpy(dest, source, sizeof(z_stream));
ds = (deflate_state *) ZALLOC(dest, 1, sizeof(deflate_state));
if (ds == Z_NULL) return Z_MEM_ERROR;
dest->state = (struct internal_state FAR *) ds;
zmemcpy(ds, ss, sizeof(deflate_state));
ds->strm = dest;
ds->window = (Bytef *) ZALLOC(dest, ds->w_size, 2*sizeof(Byte));
ds->prev = (Posf *) ZALLOC(dest, ds->w_size, sizeof(Pos));
ds->head = (Posf *) ZALLOC(dest, ds->hash_size, sizeof(Pos));
overlay = (ushf *) ZALLOC(dest, ds->lit_bufsize, sizeof(ush)+2);
ds->pending_buf = (uchf *) overlay;
if (ds->window == Z_NULL || ds->prev == Z_NULL || ds->head == Z_NULL ||
ds->pending_buf == Z_NULL) {
deflateEnd (dest);
return Z_MEM_ERROR;
}
/* following zmemcpy do not work for 16-bit MSDOS */
zmemcpy(ds->window, ss->window, ds->w_size * 2 * sizeof(Byte));
zmemcpy(ds->prev, ss->prev, ds->w_size * sizeof(Pos));
zmemcpy(ds->head, ss->head, ds->hash_size * sizeof(Pos));
zmemcpy(ds->pending_buf, ss->pending_buf, (uInt)ds->pending_buf_size);
ds->pending_out = ds->pending_buf + (ss->pending_out - ss->pending_buf);
ds->d_buf = overlay + ds->lit_bufsize/sizeof(ush);
ds->l_buf = ds->pending_buf + (1+sizeof(ush))*ds->lit_bufsize;
ds->l_desc.dyn_tree = ds->dyn_ltree;
ds->d_desc.dyn_tree = ds->dyn_dtree;
ds->bl_desc.dyn_tree = ds->bl_tree;
return Z_OK;
#endif /* MAXSEG_64K */
}
/* ===========================================================================
* Read a new buffer from the current input stream, update the adler32
* and total number of bytes read. All deflate() input goes through
* this function so some applications may wish to modify it to avoid
* allocating a large strm->next_in buffer and copying from it.
* (See also flush_pending()).
*/
local int read_buf(strm, buf, size)
z_streamp strm;
Bytef *buf;
unsigned size;
{
unsigned len = strm->avail_in;
if (len > size) len = size;
if (len == 0) return 0;
strm->avail_in -= len;
if (strm->state->wrap == 1) {
strm->adler = adler32(strm->adler, strm->next_in, len);
}
#ifdef GZIP
else if (strm->state->wrap == 2) {
strm->adler = crc32(strm->adler, strm->next_in, len);
}
#endif
zmemcpy(buf, strm->next_in, len);
strm->next_in += len;
strm->total_in += len;
return (int)len;
}
/* ===========================================================================
* Initialize the "longest match" routines for a new zlib stream
*/
local void lm_init (s)
deflate_state *s;
{
s->window_size = (ulg)2L*s->w_size;
CLEAR_HASH(s);
/* Set the default configuration parameters:
*/
s->max_lazy_match = configuration_table[s->level].max_lazy;
s->good_match = configuration_table[s->level].good_length;
s->nice_match = configuration_table[s->level].nice_length;
s->max_chain_length = configuration_table[s->level].max_chain;
s->strstart = 0;
s->block_start = 0L;
s->lookahead = 0;
s->match_length = s->prev_length = MIN_MATCH-1;
s->match_available = 0;
s->ins_h = 0;
#ifndef FASTEST
#ifdef ASMV
match_init(); /* initialize the asm code */
#endif
#endif
}
#ifndef FASTEST
/* ===========================================================================
* Set match_start to the longest match starting at the given string and
* return its length. Matches shorter or equal to prev_length are discarded,
* in which case the result is equal to prev_length and match_start is
* garbage.
* IN assertions: cur_match is the head of the hash chain for the current
* string (strstart) and its distance is <= MAX_DIST, and prev_length >= 1
* OUT assertion: the match length is not greater than s->lookahead.
*/
#ifndef ASMV
/* For 80x86 and 680x0, an optimized version will be provided in match.asm or
* match.S. The code will be functionally equivalent.
*/
uInt longest_match(s, cur_match)
deflate_state *s;
IPos cur_match; /* current match */
{
unsigned chain_length = s->max_chain_length;/* max hash chain length */
register Bytef *scan = s->window + s->strstart; /* current string */
register Bytef *match; /* matched string */
register int len; /* length of current match */
int best_len = s->prev_length; /* best match length so far */
int nice_match = s->nice_match; /* stop if match long enough */
IPos limit = s->strstart > (IPos)MAX_DIST(s) ?
s->strstart - (IPos)MAX_DIST(s) : NIL;
/* Stop when cur_match becomes <= limit. To simplify the code,
* we prevent matches with the string of window index 0.
*/
Posf *prev = s->prev;
uInt wmask = s->w_mask;
#ifdef UNALIGNED_OK
/* Compare two bytes at a time. Note: this is not always beneficial.
* Try with and without -DUNALIGNED_OK to check.
*/
register Bytef *strend = s->window + s->strstart + MAX_MATCH - 1;
register ush scan_start = *(ushf*)scan;
register ush scan_end = *(ushf*)(scan+best_len-1);
#else
register Bytef *strend = s->window + s->strstart + MAX_MATCH;
register Byte scan_end1 = scan[best_len-1];
register Byte scan_end = scan[best_len];
#endif
/* The code is optimized for HASH_BITS >= 8 and MAX_MATCH-2 multiple of 16.
* It is easy to get rid of this optimization if necessary.
*/
Assert(s->hash_bits >= 8 && MAX_MATCH == 258, "Code too clever");
/* Do not waste too much time if we already have a good match: */
if (s->prev_length >= s->good_match) {
chain_length >>= 2;
}
/* Do not look for matches beyond the end of the input. This is necessary
* to make deflate deterministic.
*/
if ((uInt)nice_match > s->lookahead) nice_match = s->lookahead;
Assert((ulg)s->strstart <= s->window_size-MIN_LOOKAHEAD, "need lookahead");
do {
Assert(cur_match < s->strstart, "no future");
match = s->window + cur_match;
/* Skip to next match if the match length cannot increase
* or if the match length is less than 2. Note that the checks below
* for insufficient lookahead only occur occasionally for performance
* reasons. Therefore uninitialized memory will be accessed, and
* conditional jumps will be made that depend on those values.
* However the length of the match is limited to the lookahead, so
* the output of deflate is not affected by the uninitialized values.
*/
#if (defined(UNALIGNED_OK) && MAX_MATCH == 258)
/* This code assumes sizeof(unsigned short) == 2. Do not use
* UNALIGNED_OK if your compiler uses a different size.
*/
if (*(ushf*)(match+best_len-1) != scan_end ||
*(ushf*)match != scan_start) continue;
/* It is not necessary to compare scan[2] and match[2] since they are
* always equal when the other bytes match, given that the hash keys
* are equal and that HASH_BITS >= 8. Compare 2 bytes at a time at
* strstart+3, +5, ... up to strstart+257. We check for insufficient
* lookahead only every 4th comparison; the 128th check will be made
* at strstart+257. If MAX_MATCH-2 is not a multiple of 8, it is
* necessary to put more guard bytes at the end of the window, or
* to check more often for insufficient lookahead.
*/
Assert(scan[2] == match[2], "scan[2]?");
scan++, match++;
do {
} while (*(ushf*)(scan+=2) == *(ushf*)(match+=2) &&
*(ushf*)(scan+=2) == *(ushf*)(match+=2) &&
*(ushf*)(scan+=2) == *(ushf*)(match+=2) &&
*(ushf*)(scan+=2) == *(ushf*)(match+=2) &&
scan < strend);
/* The funny "do {}" generates better code on most compilers */
/* Here, scan <= window+strstart+257 */
Assert(scan <= s->window+(unsigned)(s->window_size-1), "wild scan");
if (*scan == *match) scan++;
len = (MAX_MATCH - 1) - (int)(strend-scan);
scan = strend - (MAX_MATCH-1);
#else /* UNALIGNED_OK */
if (match[best_len] != scan_end ||
match[best_len-1] != scan_end1 ||
*match != *scan ||
*++match != scan[1]) continue;
/* The check at best_len-1 can be removed because it will be made
* again later. (This heuristic is not always a win.)
* It is not necessary to compare scan[2] and match[2] since they
* are always equal when the other bytes match, given that
* the hash keys are equal and that HASH_BITS >= 8.
*/
scan += 2, match++;
Assert(*scan == *match, "match[2]?");
/* We check for insufficient lookahead only every 8th comparison;
* the 256th check will be made at strstart+258.
*/
do {
} while (*++scan == *++match && *++scan == *++match &&
*++scan == *++match && *++scan == *++match &&
*++scan == *++match && *++scan == *++match &&
*++scan == *++match && *++scan == *++match &&
scan < strend);
Assert(scan <= s->window+(unsigned)(s->window_size-1), "wild scan");
len = MAX_MATCH - (int)(strend - scan);
scan = strend - MAX_MATCH;
#endif /* UNALIGNED_OK */
if (len > best_len) {
s->match_start = cur_match;
best_len = len;
if (len >= nice_match) break;
#ifdef UNALIGNED_OK
scan_end = *(ushf*)(scan+best_len-1);
#else
scan_end1 = scan[best_len-1];
scan_end = scan[best_len];
#endif
}
} while ((cur_match = prev[cur_match & wmask]) > limit
&& --chain_length != 0);
if ((uInt)best_len <= s->lookahead) return (uInt)best_len;
return s->lookahead;
}
#endif /* ASMV */
#endif /* FASTEST */
/* ---------------------------------------------------------------------------
* Optimized version for level == 1 or strategy == Z_RLE only
*/
local uInt longest_match_fast(s, cur_match)
deflate_state *s;
IPos cur_match; /* current match */
{
register Bytef *scan = s->window + s->strstart; /* current string */
register Bytef *match; /* matched string */
register int len; /* length of current match */
register Bytef *strend = s->window + s->strstart + MAX_MATCH;
/* The code is optimized for HASH_BITS >= 8 and MAX_MATCH-2 multiple of 16.
* It is easy to get rid of this optimization if necessary.
*/
Assert(s->hash_bits >= 8 && MAX_MATCH == 258, "Code too clever");
Assert((ulg)s->strstart <= s->window_size-MIN_LOOKAHEAD, "need lookahead");
Assert(cur_match < s->strstart, "no future");
match = s->window + cur_match;
/* Return failure if the match length is less than 2:
*/
if (match[0] != scan[0] || match[1] != scan[1]) return MIN_MATCH-1;
/* The check at best_len-1 can be removed because it will be made
* again later. (This heuristic is not always a win.)
* It is not necessary to compare scan[2] and match[2] since they
* are always equal when the other bytes match, given that
* the hash keys are equal and that HASH_BITS >= 8.
*/
scan += 2, match += 2;
Assert(*scan == *match, "match[2]?");
/* We check for insufficient lookahead only every 8th comparison;
* the 256th check will be made at strstart+258.
*/
do {
} while (*++scan == *++match && *++scan == *++match &&
*++scan == *++match && *++scan == *++match &&
*++scan == *++match && *++scan == *++match &&
*++scan == *++match && *++scan == *++match &&
scan < strend);
Assert(scan <= s->window+(unsigned)(s->window_size-1), "wild scan");
len = MAX_MATCH - (int)(strend - scan);
if (len < MIN_MATCH) return MIN_MATCH - 1;
s->match_start = cur_match;
return (uInt)len <= s->lookahead ? (uInt)len : s->lookahead;
}
#ifdef DEBUG
/* ===========================================================================
* Check that the match at match_start is indeed a match.
*/
local void check_match(s, start, match, length)
deflate_state *s;
IPos start, match;
int length;
{
/* check that the match is indeed a match */
if (zmemcmp(s->window + match,
s->window + start, length) != EQUAL) {
fprintf(stderr, " start %u, match %u, length %d\n",
start, match, length);
do {
fprintf(stderr, "%c%c", s->window[match++], s->window[start++]);
} while (--length != 0);
z_error("invalid match");
}
if (z_verbose > 1) {
fprintf(stderr,"\\[%d,%d]", start-match, length);
do { putc(s->window[start++], stderr); } while (--length != 0);
}
}
#else
# define check_match(s, start, match, length)
#endif /* DEBUG */
/* ===========================================================================
* Fill the window when the lookahead becomes insufficient.
* Updates strstart and lookahead.
*
* IN assertion: lookahead < MIN_LOOKAHEAD
* OUT assertions: strstart <= window_size-MIN_LOOKAHEAD
* At least one byte has been read, or avail_in == 0; reads are
* performed for at least two bytes (required for the zip translate_eol
* option -- not supported here).
*/
local void fill_window(s)
deflate_state *s;
{
register unsigned n, m;
register Posf *p;
unsigned more; /* Amount of free space at the end of the window. */
uInt wsize = s->w_size;
do {
more = (unsigned)(s->window_size -(ulg)s->lookahead -(ulg)s->strstart);
/* Deal with !@#$% 64K limit: */
if (sizeof(int) <= 2) {
if (more == 0 && s->strstart == 0 && s->lookahead == 0) {
more = wsize;
} else if (more == (unsigned)(-1)) {
/* Very unlikely, but possible on 16 bit machine if
* strstart == 0 && lookahead == 1 (input done a byte at time)
*/
more--;
}
}
/* If the window is almost full and there is insufficient lookahead,
* move the upper half to the lower one to make room in the upper half.
*/
if (s->strstart >= wsize+MAX_DIST(s)) {
zmemcpy(s->window, s->window+wsize, (unsigned)wsize);
s->match_start -= wsize;
s->strstart -= wsize; /* we now have strstart >= MAX_DIST */
s->block_start -= (long) wsize;
/* Slide the hash table (could be avoided with 32 bit values
at the expense of memory usage). We slide even when level == 0
to keep the hash table consistent if we switch back to level > 0
later. (Using level 0 permanently is not an optimal usage of
zlib, so we don't care about this pathological case.)
*/
/* %%% avoid this when Z_RLE */
n = s->hash_size;
p = &s->head[n];
do {
m = *--p;
*p = (Pos)(m >= wsize ? m-wsize : NIL);
} while (--n);
n = wsize;
#ifndef FASTEST
p = &s->prev[n];
do {
m = *--p;
*p = (Pos)(m >= wsize ? m-wsize : NIL);
/* If n is not on any hash chain, prev[n] is garbage but
* its value will never be used.
*/
} while (--n);
#endif
more += wsize;
}
if (s->strm->avail_in == 0) return;
/* If there was no sliding:
* strstart <= WSIZE+MAX_DIST-1 && lookahead <= MIN_LOOKAHEAD - 1 &&
* more == window_size - lookahead - strstart
* => more >= window_size - (MIN_LOOKAHEAD-1 + WSIZE + MAX_DIST-1)
* => more >= window_size - 2*WSIZE + 2
* In the BIG_MEM or MMAP case (not yet supported),
* window_size == input_size + MIN_LOOKAHEAD &&
* strstart + s->lookahead <= input_size => more >= MIN_LOOKAHEAD.
* Otherwise, window_size == 2*WSIZE so more >= 2.
* If there was sliding, more >= WSIZE. So in all cases, more >= 2.
*/
Assert(more >= 2, "more < 2");
n = read_buf(s->strm, s->window + s->strstart + s->lookahead, more);
s->lookahead += n;
/* Initialize the hash value now that we have some input: */
if (s->lookahead >= MIN_MATCH) {
s->ins_h = s->window[s->strstart];
UPDATE_HASH(s, s->ins_h, s->window[s->strstart+1]);
#if MIN_MATCH != 3
Call UPDATE_HASH() MIN_MATCH-3 more times
#endif
}
/* If the whole input has less than MIN_MATCH bytes, ins_h is garbage,
* but this is not important since only literal bytes will be emitted.
*/
} while (s->lookahead < MIN_LOOKAHEAD && s->strm->avail_in != 0);
}
/* ===========================================================================
* Flush the current block, with given end-of-file flag.
* IN assertion: strstart is set to the end of the current match.
*/
#define FLUSH_BLOCK_ONLY(s, eof) { \
_tr_flush_block(s, (s->block_start >= 0L ? \
(charf *)&s->window[(unsigned)s->block_start] : \
(charf *)Z_NULL), \
(ulg)((long)s->strstart - s->block_start), \
(eof)); \
s->block_start = s->strstart; \
flush_pending(s->strm); \
Tracev((stderr,"[FLUSH]")); \
}
/* Same but force premature exit if necessary. */
#define FLUSH_BLOCK(s, eof) { \
FLUSH_BLOCK_ONLY(s, eof); \
if (s->strm->avail_out == 0) return (eof) ? finish_started : need_more; \
}
/* ===========================================================================
* Copy without compression as much as possible from the input stream, return
* the current block state.
* This function does not insert new strings in the dictionary since
* uncompressible data is probably not useful. This function is used
* only for the level=0 compression option.
* NOTE: this function should be optimized to avoid extra copying from
* window to pending_buf.
*/
local block_state deflate_stored(s, flush)
deflate_state *s;
int flush;
{
/* Stored blocks are limited to 0xffff bytes, pending_buf is limited
* to pending_buf_size, and each stored block has a 5 byte header:
*/
ulg max_block_size = 0xffff;
ulg max_start;
if (max_block_size > s->pending_buf_size - 5) {
max_block_size = s->pending_buf_size - 5;
}
/* Copy as much as possible from input to output: */
for (;;) {
/* Fill the window as much as possible: */
if (s->lookahead <= 1) {
Assert(s->strstart < s->w_size+MAX_DIST(s) ||
s->block_start >= (long)s->w_size, "slide too late");
fill_window(s);
if (s->lookahead == 0 && flush == Z_NO_FLUSH) return need_more;
if (s->lookahead == 0) break; /* flush the current block */
}
Assert(s->block_start >= 0L, "block gone");
s->strstart += s->lookahead;
s->lookahead = 0;
/* Emit a stored block if pending_buf will be full: */
max_start = s->block_start + max_block_size;
if (s->strstart == 0 || (ulg)s->strstart >= max_start) {
/* strstart == 0 is possible when wraparound on 16-bit machine */
s->lookahead = (uInt)(s->strstart - max_start);
s->strstart = (uInt)max_start;
FLUSH_BLOCK(s, 0);
}
/* Flush if we may have to slide, otherwise block_start may become
* negative and the data will be gone:
*/
if (s->strstart - (uInt)s->block_start >= MAX_DIST(s)) {
FLUSH_BLOCK(s, 0);
}
}
FLUSH_BLOCK(s, flush == Z_FINISH);
return flush == Z_FINISH ? finish_done : block_done;
}
/* ===========================================================================
* Compress as much as possible from the input stream, return the current
* block state.
* This function does not perform lazy evaluation of matches and inserts
* new strings in the dictionary only for unmatched strings or for short
* matches. It is used only for the fast compression options.
*/
local block_state deflate_fast(s, flush)
deflate_state *s;
int flush;
{
IPos hash_head = NIL; /* head of the hash chain */
int bflush; /* set if current block must be flushed */
for (;;) {
/* Make sure that we always have enough lookahead, except
* at the end of the input file. We need MAX_MATCH bytes
* for the next match, plus MIN_MATCH bytes to insert the
* string following the next match.
*/
if (s->lookahead < MIN_LOOKAHEAD) {
fill_window(s);
if (s->lookahead < MIN_LOOKAHEAD && flush == Z_NO_FLUSH) {
return need_more;
}
if (s->lookahead == 0) break; /* flush the current block */
}
/* Insert the string window[strstart .. strstart+2] in the
* dictionary, and set hash_head to the head of the hash chain:
*/
if (s->lookahead >= MIN_MATCH) {
INSERT_STRING(s, s->strstart, hash_head);
}
/* Find the longest match, discarding those <= prev_length.
* At this point we have always match_length < MIN_MATCH
*/
if (hash_head != NIL && s->strstart - hash_head <= MAX_DIST(s)) {
/* To simplify the code, we prevent matches with the string
* of window index 0 (in particular we have to avoid a match
* of the string with itself at the start of the input file).
*/
#ifdef FASTEST
if ((s->strategy != Z_HUFFMAN_ONLY && s->strategy != Z_RLE) ||
(s->strategy == Z_RLE && s->strstart - hash_head == 1)) {
s->match_length = longest_match_fast (s, hash_head);
}
#else
if (s->strategy != Z_HUFFMAN_ONLY && s->strategy != Z_RLE) {
s->match_length = longest_match (s, hash_head);
} else if (s->strategy == Z_RLE && s->strstart - hash_head == 1) {
s->match_length = longest_match_fast (s, hash_head);
}
#endif
/* longest_match() or longest_match_fast() sets match_start */
}
if (s->match_length >= MIN_MATCH) {
check_match(s, s->strstart, s->match_start, s->match_length);
_tr_tally_dist(s, s->strstart - s->match_start,
s->match_length - MIN_MATCH, bflush);
s->lookahead -= s->match_length;
/* Insert new strings in the hash table only if the match length
* is not too large. This saves time but degrades compression.
*/
#ifndef FASTEST
if (s->match_length <= s->max_insert_length &&
s->lookahead >= MIN_MATCH) {
s->match_length--; /* string at strstart already in table */
do {
s->strstart++;
INSERT_STRING(s, s->strstart, hash_head);
/* strstart never exceeds WSIZE-MAX_MATCH, so there are
* always MIN_MATCH bytes ahead.
*/
} while (--s->match_length != 0);
s->strstart++;
} else
#endif
{
s->strstart += s->match_length;
s->match_length = 0;
s->ins_h = s->window[s->strstart];
UPDATE_HASH(s, s->ins_h, s->window[s->strstart+1]);
#if MIN_MATCH != 3
Call UPDATE_HASH() MIN_MATCH-3 more times
#endif
/* If lookahead < MIN_MATCH, ins_h is garbage, but it does not
* matter since it will be recomputed at next deflate call.
*/
}
} else {
/* No match, output a literal byte */
Tracevv((stderr,"%c", s->window[s->strstart]));
_tr_tally_lit (s, s->window[s->strstart], bflush);
s->lookahead--;
s->strstart++;
}
if (bflush) FLUSH_BLOCK(s, 0);
}
FLUSH_BLOCK(s, flush == Z_FINISH);
return flush == Z_FINISH ? finish_done : block_done;
}
#ifndef FASTEST
/* ===========================================================================
* Same as above, but achieves better compression. We use a lazy
* evaluation for matches: a match is finally adopted only if there is
* no better match at the next window position.
*/
local block_state deflate_slow(s, flush)
deflate_state *s;
int flush;
{
IPos hash_head = NIL; /* head of hash chain */
int bflush; /* set if current block must be flushed */
/* Process the input block. */
for (;;) {
/* Make sure that we always have enough lookahead, except
* at the end of the input file. We need MAX_MATCH bytes
* for the next match, plus MIN_MATCH bytes to insert the
* string following the next match.
*/
if (s->lookahead < MIN_LOOKAHEAD) {
fill_window(s);
if (s->lookahead < MIN_LOOKAHEAD && flush == Z_NO_FLUSH) {
return need_more;
}
if (s->lookahead == 0) break; /* flush the current block */
}
/* Insert the string window[strstart .. strstart+2] in the
* dictionary, and set hash_head to the head of the hash chain:
*/
if (s->lookahead >= MIN_MATCH) {
INSERT_STRING(s, s->strstart, hash_head);
}
/* Find the longest match, discarding those <= prev_length.
*/
s->prev_length = s->match_length, s->prev_match = s->match_start;
s->match_length = MIN_MATCH-1;
if (hash_head != NIL && s->prev_length < s->max_lazy_match &&
s->strstart - hash_head <= MAX_DIST(s)) {
/* To simplify the code, we prevent matches with the string
* of window index 0 (in particular we have to avoid a match
* of the string with itself at the start of the input file).
*/
if (s->strategy != Z_HUFFMAN_ONLY && s->strategy != Z_RLE) {
s->match_length = longest_match (s, hash_head);
} else if (s->strategy == Z_RLE && s->strstart - hash_head == 1) {
s->match_length = longest_match_fast (s, hash_head);
}
/* longest_match() or longest_match_fast() sets match_start */
if (s->match_length <= 5 && (s->strategy == Z_FILTERED
#if TOO_FAR <= 32767
|| (s->match_length == MIN_MATCH &&
s->strstart - s->match_start > TOO_FAR)
#endif
)) {
/* If prev_match is also MIN_MATCH, match_start is garbage
* but we will ignore the current match anyway.
*/
s->match_length = MIN_MATCH-1;
}
}
/* If there was a match at the previous step and the current
* match is not better, output the previous match:
*/
if (s->prev_length >= MIN_MATCH && s->match_length <= s->prev_length) {
uInt max_insert = s->strstart + s->lookahead - MIN_MATCH;
/* Do not insert strings in hash table beyond this. */
check_match(s, s->strstart-1, s->prev_match, s->prev_length);
_tr_tally_dist(s, s->strstart -1 - s->prev_match,
s->prev_length - MIN_MATCH, bflush);
/* Insert in hash table all strings up to the end of the match.
* strstart-1 and strstart are already inserted. If there is not
* enough lookahead, the last two strings are not inserted in
* the hash table.
*/
s->lookahead -= s->prev_length-1;
s->prev_length -= 2;
do {
if (++s->strstart <= max_insert) {
INSERT_STRING(s, s->strstart, hash_head);
}
} while (--s->prev_length != 0);
s->match_available = 0;
s->match_length = MIN_MATCH-1;
s->strstart++;
if (bflush) FLUSH_BLOCK(s, 0);
} else if (s->match_available) {
/* If there was no match at the previous position, output a
* single literal. If there was a match but the current match
* is longer, truncate the previous match to a single literal.
*/
Tracevv((stderr,"%c", s->window[s->strstart-1]));
_tr_tally_lit(s, s->window[s->strstart-1], bflush);
if (bflush) {
FLUSH_BLOCK_ONLY(s, 0);
}
s->strstart++;
s->lookahead--;
if (s->strm->avail_out == 0) return need_more;
} else {
/* There is no previous match to compare with, wait for
* the next step to decide.
*/
s->match_available = 1;
s->strstart++;
s->lookahead--;
}
}
Assert (flush != Z_NO_FLUSH, "no flush?");
if (s->match_available) {
Tracevv((stderr,"%c", s->window[s->strstart-1]));
_tr_tally_lit(s, s->window[s->strstart-1], bflush);
s->match_available = 0;
}
FLUSH_BLOCK(s, flush == Z_FINISH);
return flush == Z_FINISH ? finish_done : block_done;
}
#endif /* FASTEST */
#if 0
/* ===========================================================================
* For Z_RLE, simply look for runs of bytes, generate matches only of distance
* one. Do not maintain a hash table. (It will be regenerated if this run of
* deflate switches away from Z_RLE.)
*/
local block_state deflate_rle(s, flush)
deflate_state *s;
int flush;
{
int bflush; /* set if current block must be flushed */
uInt run; /* length of run */
uInt max; /* maximum length of run */
uInt prev; /* byte at distance one to match */
Bytef *scan; /* scan for end of run */
for (;;) {
/* Make sure that we always have enough lookahead, except
* at the end of the input file. We need MAX_MATCH bytes
* for the longest encodable run.
*/
if (s->lookahead < MAX_MATCH) {
fill_window(s);
if (s->lookahead < MAX_MATCH && flush == Z_NO_FLUSH) {
return need_more;
}
if (s->lookahead == 0) break; /* flush the current block */
}
/* See how many times the previous byte repeats */
run = 0;
if (s->strstart > 0) { /* if there is a previous byte, that is */
max = s->lookahead < MAX_MATCH ? s->lookahead : MAX_MATCH;
scan = s->window + s->strstart - 1;
prev = *scan++;
do {
if (*scan++ != prev)
break;
} while (++run < max);
}
/* Emit match if have run of MIN_MATCH or longer, else emit literal */
if (run >= MIN_MATCH) {
check_match(s, s->strstart, s->strstart - 1, run);
_tr_tally_dist(s, 1, run - MIN_MATCH, bflush);
s->lookahead -= run;
s->strstart += run;
} else {
/* No match, output a literal byte */
Tracevv((stderr,"%c", s->window[s->strstart]));
_tr_tally_lit (s, s->window[s->strstart], bflush);
s->lookahead--;
s->strstart++;
}
if (bflush) FLUSH_BLOCK(s, 0);
}
FLUSH_BLOCK(s, flush == Z_FINISH);
return flush == Z_FINISH ? finish_done : block_done;
}
#endif
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2009-09-11 18:58 ` optimize slowdown problems on longest_match func detect Bernd Roesch
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