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/cvs/liblzf/lzf_c.c
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Comparing liblzf/lzf_c.c (file contents):
Revision 1.8 by root, Thu Mar 3 17:06:44 2005 UTC vs.
Revision 1.11 by root, Fri Feb 16 22:13:43 2007 UTC

… …
44 * don't play with this unless you benchmark! 44 * don't play with this unless you benchmark!
45 * decompression is not dependent on the hash function 45 * decompression is not dependent on the hash function
46 * the hashing function might seem strange, just believe me 46 * the hashing function might seem strange, just believe me
47 * it works ;) 47 * it works ;)
48 */ 48 */
49#ifndef FRST
49#define FRST(p) (((p[0]) << 8) + p[1]) 50# define FRST(p) (((p[0]) << 8) | p[1])
50#define NEXT(v,p) (((v) << 8) + p[2]) 51# define NEXT(v,p) (((v) << 8) | p[2])
51#define IDX(h) ((((h ^ (h << 5)) >> (3*8 - HLOG)) - h*5) & (HSIZE - 1)) 52# define IDX(h) ((((h ^ (h << 5)) >> (3*8 - HLOG)) - h*5) & (HSIZE - 1))
53#endif
52/* 54/*
53 * IDX works because it is very similar to a multiplicative hash, e.g. 55 * IDX works because it is very similar to a multiplicative hash, e.g.
54 * ((h * 57321 >> (3*8 - HLOG)) & (HSIZE - 1)) 56 * ((h * 57321 >> (3*8 - HLOG)) & (HSIZE - 1))
55 * the latter is also quite fast on newer CPUs, and sligthly better 57 * the latter is also quite fast on newer CPUs, and sligthly better
56 * 58 *
… …
71 73
72/* 74/*
73 * compressed format 75 * compressed format
74 * 76 *
75 * 000LLLLL <L+1> ; literal 77 * 000LLLLL <L+1> ; literal
76 * LLLOOOOO oooooooo ; backref L 78 * LLLooooo oooooooo ; backref L
77 * 111OOOOO LLLLLLLL oooooooo ; backref L+7 79 * 111ooooo LLLLLLLL oooooooo ; backref L+7
78 * 80 *
79 */ 81 */
80 82
81unsigned int 83unsigned int
82lzf_compress (const void *const in_data, unsigned int in_len, 84lzf_compress (const void *const in_data, unsigned int in_len,
83 void *out_data, unsigned int out_len 85 void *out_data, unsigned int out_len
84#if LZF_STATE_ARG 86#if LZF_STATE_ARG
85 , LZF_STATE *htab 87 , LZF_STATE htab
86#endif 88#endif
87 ) 89 )
88{ 90{
89#if !LZF_STATE_ARG 91#if !LZF_STATE_ARG
90 LZF_STATE htab; 92 LZF_STATE htab;
… …
137 /* match found at *ref++ */ 139 /* match found at *ref++ */
138 unsigned int len = 2; 140 unsigned int len = 2;
139 unsigned int maxlen = in_end - ip - len; 141 unsigned int maxlen = in_end - ip - len;
140 maxlen = maxlen > MAX_REF ? MAX_REF : maxlen; 142 maxlen = maxlen > MAX_REF ? MAX_REF : maxlen;
141 143
144 if (op + lit + 1 + 3 >= out_end)
145 return 0;
146
142 do 147 do
143 len++; 148 len++;
144 while (len < maxlen && ref[len] == ip[len]); 149 while (len < maxlen && ref[len] == ip[len]);
145
146 if (op + lit + 1 + 3 >= out_end)
147 return 0;
148 150
149 if (lit) 151 if (lit)
150 { 152 {
151 *op++ = lit - 1; 153 *op++ = lit - 1;
152 lit = -lit; 154 lit = -lit;
… …
168 *op++ = len - 7; 170 *op++ = len - 7;
169 } 171 }
170 172
171 *op++ = off; 173 *op++ = off;
172 174
173#if ULTRA_FAST 175#if ULTRA_FAST || VERY_FAST
174 ip += len; 176 ip += len;
177#if VERY_FAST && !ULTRA_FAST
178 --ip;
179#endif
175 hval = FRST (ip); 180 hval = FRST (ip);
181
176 hval = NEXT (hval, ip); 182 hval = NEXT (hval, ip);
177 htab[IDX (hval)] = ip; 183 htab[IDX (hval)] = ip;
178 ip++; 184 ip++;
185
186#if VERY_FAST && !ULTRA_FAST
187 hval = NEXT (hval, ip);
188 htab[IDX (hval)] = ip;
189 ip++;
190#endif
179#else 191#else
180 do 192 do
181 { 193 {
182 hval = NEXT (hval, ip); 194 hval = NEXT (hval, ip);
183 htab[IDX (hval)] = ip; 195 htab[IDX (hval)] = ip;

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