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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 1.13 by root, Tue Jun 19 21:25:07 2007 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 */
49#ifndef FRST
39#define FRST(p) (((p[0]) << 8) + p[1]) 50# define FRST(p) (((p[0]) << 8) | p[1])
40#define NEXT(v,p) (((v) << 8) + p[2]) 51# define NEXT(v,p) (((v) << 8) | p[2])
41#define IDX(h) ((((h ^ (h << 5)) >> (3*8 - HLOG)) + h*3) & (HSIZE - 1)) 52# define IDX(h) ((((h ^ (h << 5)) >> (3*8 - HLOG)) - h*5) & (HSIZE - 1))
53/*# define IDX(h) ((ip[0] * 121 ^ ip[1] * 33 ^ ip[2] * 1) & (HSIZE-1))*/
54#endif
42/* 55/*
43 * IDX works because it is very similar to a multiplicative hash, e.g. 56 * IDX works because it is very similar to a multiplicative hash, e.g.
44 * (h * 57321 >> (3*8 - HLOG)) 57 * ((h * 57321 >> (3*8 - HLOG)) & (HSIZE - 1))
58 * the latter is also quite fast on newer CPUs, and compresses similarly.
59 *
45 * the next one is also quite good, albeit slow ;) 60 * the next one is also quite good, albeit slow ;)
46 * (int)(cos(h & 0xffffff) * 1e6) 61 * (int)(cos(h & 0xffffff) * 1e6)
47 */ 62 */
48 63
49#if 0 64#if 0
50/* original lzv-like hash function */ 65/* original lzv-like hash function, much worse and thus slower */
51# define FRST(p) (p[0] << 5) ^ p[1] 66# define FRST(p) (p[0] << 5) ^ p[1]
52# define NEXT(v,p) ((v) << 5) ^ p[2] 67# define NEXT(v,p) ((v) << 5) ^ p[2]
53# define IDX(h) ((h) & (HSIZE - 1)) 68# define IDX(h) ((h) & (HSIZE - 1))
54#endif 69#endif
55 70
56#define MAX_LIT (1 << 5) 71#define MAX_LIT (1 << 5)
57#define MAX_OFF (1 << 13) 72#define MAX_OFF (1 << 13)
58#define MAX_REF ((1 << 8) + (1 << 3)) 73#define MAX_REF ((1 << 8) + (1 << 3))
59 74
60/* 75/*
61 * compressed format 76 * compressed format
62 * 77 *
63 * 000LLLLL <L+1> ; literal 78 * 000LLLLL <L+1> ; literal
64 * LLLOOOOO oooooooo ; backref L 79 * LLLooooo oooooooo ; backref L
65 * 111OOOOO LLLLLLLL oooooooo ; backref L+7 80 * 111ooooo LLLLLLLL oooooooo ; backref L+7
66 * 81 *
67 */ 82 */
68 83
69unsigned int 84unsigned int
70lzf_compress (const void *const in_data, unsigned int in_len, 85lzf_compress (const void *const in_data, unsigned int in_len,
71 void *out_data, unsigned int out_len 86 void *out_data, unsigned int out_len
72#if LZF_STATE_ARG 87#if LZF_STATE_ARG
73 , LZF_STATE *htab 88 , LZF_STATE htab
74#endif 89#endif
75 ) 90 )
76{ 91{
77#if !LZF_STATE_ARG 92#if !LZF_STATE_ARG
78 LZF_STATE htab; 93 LZF_STATE htab;
… …
125 /* match found at *ref++ */ 140 /* match found at *ref++ */
126 unsigned int len = 2; 141 unsigned int len = 2;
127 unsigned int maxlen = in_end - ip - len; 142 unsigned int maxlen = in_end - ip - len;
128 maxlen = maxlen > MAX_REF ? MAX_REF : maxlen; 143 maxlen = maxlen > MAX_REF ? MAX_REF : maxlen;
129 144
145 if (op + lit + 1 + 3 >= out_end)
146 return 0;
147
130 do 148 do
131 len++; 149 len++;
132 while (len < maxlen && ref[len] == ip[len]); 150 while (len < maxlen && ref[len] == ip[len]);
133
134 if (op + lit + 1 + 3 >= out_end)
135 return 0;
136 151
137 if (lit) 152 if (lit)
138 { 153 {
139 *op++ = lit - 1; 154 *op++ = lit - 1;
140 lit = -lit; 155 lit = -lit;
… …
156 *op++ = len - 7; 171 *op++ = len - 7;
157 } 172 }
158 173
159 *op++ = off; 174 *op++ = off;
160 175
161#if ULTRA_FAST 176#if ULTRA_FAST || VERY_FAST
162 ip += len; 177 ip += len;
178#if VERY_FAST && !ULTRA_FAST
179 --ip;
180#endif
163 hval = FRST (ip); 181 hval = FRST (ip);
182
164 hval = NEXT (hval, ip); 183 hval = NEXT (hval, ip);
165 htab[IDX (hval)] = ip; 184 htab[IDX (hval)] = ip;
166 ip++; 185 ip++;
186
187#if VERY_FAST && !ULTRA_FAST
188 hval = NEXT (hval, ip);
189 htab[IDX (hval)] = ip;
190 ip++;
191#endif
167#else 192#else
168 do 193 do
169 { 194 {
170 hval = NEXT (hval, ip); 195 hval = NEXT (hval, ip);
171 htab[IDX (hval)] = ip; 196 htab[IDX (hval)] = ip;

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