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Comparing liblzf/lzf_c.c (file contents):
Revision 1.5 by pcg, Mon Dec 29 12:48:16 2003 UTC vs.
Revision 1.9 by root, Tue Mar 8 19:59:52 2005 UTC

1/* 1/*
2 * Copyright (c) 2000-2003 Marc Alexander Lehmann <pcg@goof.com> 2 * Copyright (c) 2000-2005 Marc Alexander Lehmann <schmorp@schmorp.de>
3 * 3 *
4 * Redistribution and use in source and binary forms, with or without modifica- 4 * Redistribution and use in source and binary forms, with or without modifica-
5 * tion, are permitted provided that the following conditions are met: 5 * tion, are permitted provided that the following conditions are met:
6 * 6 *
7 * 1. Redistributions of source code must retain the above copyright notice, 7 * 1. Redistributions of source code must retain the above copyright notice,
… …
22 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; 22 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
23 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, 23 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
24 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTH- 24 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTH-
25 * ERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED 25 * ERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
26 * OF THE POSSIBILITY OF SUCH DAMAGE. 26 * OF THE POSSIBILITY OF SUCH DAMAGE.
27 *
28 * Alternatively, the contents of this file may be used under the terms of
29 * the GNU General Public License version 2 (the "GPL"), in which case the
30 * provisions of the GPL are applicable instead of the above. If you wish to
31 * allow the use of your version of this file only under the terms of the
32 * GPL and not to allow others to use your version of this file under the
33 * BSD license, indicate your decision by deleting the provisions above and
34 * replace them with the notice and other provisions required by the GPL. If
35 * you do not delete the provisions above, a recipient may use your version
36 * of this file under either the BSD or the GPL.
27 */ 37 */
28 38
29#include "lzfP.h" 39#include "lzfP.h"
30 40
31#define HSIZE (1 << (HLOG)) 41#define HSIZE (1 << (HLOG))
… …
34 * don't play with this unless you benchmark! 44 * don't play with this unless you benchmark!
35 * decompression is not dependent on the hash function 45 * decompression is not dependent on the hash function
36 * the hashing function might seem strange, just believe me 46 * the hashing function might seem strange, just believe me
37 * it works ;) 47 * it works ;)
38 */ 48 */
39#define FRST(p) (((p[0]) << 8) + p[1]) 49#define FRST(p) (((p[0]) << 8) | p[1])
40#define NEXT(v,p) (((v) << 8) + p[2]) 50#define NEXT(v,p) (((v) << 8) | p[2])
41#define IDX(h) ((((h ^ (h << 5)) >> (3*8 - HLOG)) + h*3) & (HSIZE - 1)) 51#define IDX(h) ((((h ^ (h << 5)) >> (3*8 - HLOG)) - h*5) & (HSIZE - 1))
42/* 52/*
43 * IDX works because it is very similar to a multiplicative hash, e.g. 53 * IDX works because it is very similar to a multiplicative hash, e.g.
44 * (h * 57321 >> (3*8 - HLOG)) 54 * ((h * 57321 >> (3*8 - HLOG)) & (HSIZE - 1))
55 * the latter is also quite fast on newer CPUs, and sligthly better
56 *
45 * the next one is also quite good, albeit slow ;) 57 * the next one is also quite good, albeit slow ;)
46 * (int)(cos(h & 0xffffff) * 1e6) 58 * (int)(cos(h & 0xffffff) * 1e6)
47 */ 59 */
48 60
49#if 0 61#if 0
50/* original lzv-like hash function */ 62/* original lzv-like hash function, much worse and thus slower */
51# define FRST(p) (p[0] << 5) ^ p[1] 63# define FRST(p) (p[0] << 5) ^ p[1]
52# define NEXT(v,p) ((v) << 5) ^ p[2] 64# define NEXT(v,p) ((v) << 5) ^ p[2]
53# define IDX(h) ((h) & (HSIZE - 1)) 65# define IDX(h) ((h) & (HSIZE - 1))
54#endif 66#endif
55 67
… …
125 /* match found at *ref++ */ 137 /* match found at *ref++ */
126 unsigned int len = 2; 138 unsigned int len = 2;
127 unsigned int maxlen = in_end - ip - len; 139 unsigned int maxlen = in_end - ip - len;
128 maxlen = maxlen > MAX_REF ? MAX_REF : maxlen; 140 maxlen = maxlen > MAX_REF ? MAX_REF : maxlen;
129 141
142 if (op + lit + 1 + 3 >= out_end)
143 return 0;
144
130 do 145 do
131 len++; 146 len++;
132 while (len < maxlen && ref[len] == ip[len]); 147 while (len < maxlen && ref[len] == ip[len]);
133
134 if (op + lit + 1 + 3 >= out_end)
135 return 0;
136 148
137 if (lit) 149 if (lit)
138 { 150 {
139 *op++ = lit - 1; 151 *op++ = lit - 1;
140 lit = -lit; 152 lit = -lit;
… …
156 *op++ = len - 7; 168 *op++ = len - 7;
157 } 169 }
158 170
159 *op++ = off; 171 *op++ = off;
160 172
161#if ULTRA_FAST 173#if ULTRA_FAST || VERY_FAST
162 ip += len; 174 ip += len;
175#if VERY_FAST && !ULTRA_FAST
176 --ip;
177#endif
163 hval = FRST (ip); 178 hval = FRST (ip);
179
164 hval = NEXT (hval, ip); 180 hval = NEXT (hval, ip);
165 htab[IDX (hval)] = ip; 181 htab[IDX (hval)] = ip;
166 ip++; 182 ip++;
183
184#if VERY_FAST && !ULTRA_FAST
185 hval = NEXT (hval, ip);
186 htab[IDX (hval)] = ip;
187 ip++;
188#endif
167#else 189#else
168 do 190 do
169 { 191 {
170 hval = NEXT (hval, ip); 192 hval = NEXT (hval, ip);
171 htab[IDX (hval)] = ip; 193 htab[IDX (hval)] = ip;

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