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/cvs/liblzf/lzf_c.c
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Comparing liblzf/lzf_c.c (file contents):
Revision 1.17 by root, Tue Nov 13 07:54:18 2007 UTC vs.
Revision 1.22 by root, Tue Nov 13 10:41:52 2007 UTC

… …
45 * it works ;) 45 * it works ;)
46 */ 46 */
47#ifndef FRST 47#ifndef FRST
48# define FRST(p) (((p[0]) << 8) | p[1]) 48# define FRST(p) (((p[0]) << 8) | p[1])
49# define NEXT(v,p) (((v) << 8) | p[2]) 49# define NEXT(v,p) (((v) << 8) | p[2])
50# if ULTRA_FAST
51# define IDX(h) (((h >> (3*8 - HLOG)) - h ) & (HSIZE - 1))
52# elif VERY_FAST
53# define IDX(h) (((h >> (3*8 - HLOG)) - h*5) & (HSIZE - 1))
54# else
50# define IDX(h) ((((h ^ (h << 5)) >> (3*8 - HLOG)) - h*5) & (HSIZE - 1)) 55# define IDX(h) ((((h ^ (h << 5)) >> (3*8 - HLOG)) - h*5) & (HSIZE - 1))
56# endif
51/*# define IDX(h) ((ip[0] * 121 ^ ip[1] * 33 ^ ip[2] * 1) & (HSIZE-1))*/ 57/*# define IDX(h) ((ip[0] * 121 ^ ip[1] * 33 ^ ip[2] * 1) & (HSIZE-1))*/
52#endif 58#endif
53/* 59/*
54 * IDX works because it is very similar to a multiplicative hash, e.g. 60 * IDX works because it is very similar to a multiplicative hash, e.g.
55 * ((h * 57321 >> (3*8 - HLOG)) & (HSIZE - 1)) 61 * ((h * 57321 >> (3*8 - HLOG)) & (HSIZE - 1))
… …
67#endif 73#endif
68 74
69#define MAX_LIT (1 << 5) 75#define MAX_LIT (1 << 5)
70#define MAX_OFF (1 << 13) 76#define MAX_OFF (1 << 13)
71#define MAX_REF ((1 << 8) + (1 << 3)) 77#define MAX_REF ((1 << 8) + (1 << 3))
72
73#if (__i386 || __amd64) && __GNUC__ >= 3
74# define lzf_movsb(dst, src, len) \
75 asm ("rep movsb" \
76 : "=D" (dst), "=S" (src), "=c" (len) \
77 : "0" (dst), "1" (src), "2" (len));
78#endif
79 78
80#if __GNUC__ >= 3 79#if __GNUC__ >= 3
81# define expect(expr,value) __builtin_expect ((expr),(value)) 80# define expect(expr,value) __builtin_expect ((expr),(value))
82# define inline inline 81# define inline inline
83#else 82#else
… …
113 u8 *op = (u8 *)out_data; 112 u8 *op = (u8 *)out_data;
114 const u8 *in_end = ip + in_len; 113 const u8 *in_end = ip + in_len;
115 u8 *out_end = op + out_len; 114 u8 *out_end = op + out_len;
116 const u8 *ref; 115 const u8 *ref;
117 116
118 unsigned int hval = FRST (ip); 117 unsigned int hval;
119 unsigned long off; 118 unsigned long off;
120 int lit = 0; 119 int lit;
120
121 if (!in_len || !out_len)
122 return 0;
121 123
122#if INIT_HTAB 124#if INIT_HTAB
123 memset (htab, 0, sizeof (htab)); 125 memset (htab, 0, sizeof (htab));
124# if 0 126# if 0
125 for (hslot = htab; hslot < htab + HSIZE; hslot++) 127 for (hslot = htab; hslot < htab + HSIZE; hslot++)
126 *hslot++ = ip; 128 *hslot++ = ip;
127# endif 129# endif
128#endif 130#endif
129 131
130 for (;;) 132 lit = 0; op++; /* start run */
133
134 hval = FRST (ip);
135 while (ip < in_end - 2)
131 { 136 {
132 if (expect_true (ip < in_end - 2)) 137 hval = NEXT (hval, ip);
138 hslot = htab + IDX (hval);
139 ref = *hslot; *hslot = ip;
140
141 if (1
142#if INIT_HTAB && !USE_MEMCPY
143 && ref < ip /* the next test will actually take care of this, but this is faster */
144#endif
145 && (off = ip - ref - 1) < MAX_OFF
146 && ip + 4 < in_end
147 && ref > (u8 *)in_data
148#if STRICT_ALIGN
149 && ref[0] == ip[0]
150 && ref[1] == ip[1]
151 && ref[2] == ip[2]
152#else
153 && *(u16 *)ref == *(u16 *)ip
154 && ref[2] == ip[2]
155#endif
156 )
133 { 157 {
134 hval = NEXT (hval, ip);
135 hslot = htab + IDX (hval);
136 ref = *hslot; *hslot = ip;
137
138 if (1
139#if INIT_HTAB && !USE_MEMCPY
140 && ref < ip /* the next test will actually take care of this, but this is faster */
141#endif
142 && (off = ip - ref - 1) < MAX_OFF
143 && ip + 4 < in_end
144 && ref > (u8 *)in_data
145#if STRICT_ALIGN
146 && ref[0] == ip[0]
147 && ref[1] == ip[1]
148 && ref[2] == ip[2]
149#else
150 && *(u16 *)ref == *(u16 *)ip
151 && ref[2] == ip[2]
152#endif
153 )
154 {
155 /* match found at *ref++ */ 158 /* match found at *ref++ */
156 unsigned int len = 2; 159 unsigned int len = 2;
157 unsigned int maxlen = in_end - ip - len; 160 unsigned int maxlen = in_end - ip - len;
158 maxlen = maxlen > MAX_REF ? MAX_REF : maxlen; 161 maxlen = maxlen > MAX_REF ? MAX_REF : maxlen;
159 162
160 if (expect_false (op + lit + 1 + 3 >= out_end)) 163 if (expect_false (op + 1 + 3 >= out_end))
161 return 0; 164 return 0;
165
166 op [- lit - 1] = lit - 1; /* stop run */
167 op -= !lit; /* undo run if length is zero */
168
169 for (;;)
170 {
171 if (expect_true (maxlen > 16))
172 {
173 len++; if (ref [len] != ip [len]) break;
174 len++; if (ref [len] != ip [len]) break;
175 len++; if (ref [len] != ip [len]) break;
176 len++; if (ref [len] != ip [len]) break;
177
178 len++; if (ref [len] != ip [len]) break;
179 len++; if (ref [len] != ip [len]) break;
180 len++; if (ref [len] != ip [len]) break;
181 len++; if (ref [len] != ip [len]) break;
182
183 len++; if (ref [len] != ip [len]) break;
184 len++; if (ref [len] != ip [len]) break;
185 len++; if (ref [len] != ip [len]) break;
186 len++; if (ref [len] != ip [len]) break;
187
188 len++; if (ref [len] != ip [len]) break;
189 len++; if (ref [len] != ip [len]) break;
190 len++; if (ref [len] != ip [len]) break;
191 len++; if (ref [len] != ip [len]) break;
192 }
162 193
163 do 194 do
164 len++; 195 len++;
165 while (len < maxlen && ref[len] == ip[len]); 196 while (len < maxlen && ref[len] == ip[len]);
166 197
167 if (lit)
168 { 198 break;
169 *op++ = lit - 1;
170 lit = -lit;
171 do
172 *op++ = ip[lit];
173 while (++lit);
174 } 199 }
175 200
176 len -= 2; 201 len -= 2;
177 ip++; 202 ip++;
178 203
179 if (len < 7) 204 if (len < 7)
180 { 205 {
181 *op++ = (off >> 8) + (len << 5); 206 *op++ = (off >> 8) + (len << 5);
182 } 207 }
183 else 208 else
184 { 209 {
185 *op++ = (off >> 8) + ( 7 << 5); 210 *op++ = (off >> 8) + ( 7 << 5);
186 *op++ = len - 7; 211 *op++ = len - 7;
187 } 212 }
188 213
189 *op++ = off; 214 *op++ = off;
190 215
191#if ULTRA_FAST || VERY_FAST 216#if ULTRA_FAST || VERY_FAST
192 ip += len; 217 ip += len;
193#if VERY_FAST && !ULTRA_FAST 218#if VERY_FAST && !ULTRA_FAST
194 --ip; 219 --ip;
195#endif 220#endif
196 hval = FRST (ip); 221 hval = FRST (ip);
197 222
223 hval = NEXT (hval, ip);
224 htab[IDX (hval)] = ip;
225 ip++;
226
227#if VERY_FAST && !ULTRA_FAST
228 hval = NEXT (hval, ip);
229 htab[IDX (hval)] = ip;
230 ip++;
231#endif
232#else
233 do
234 {
198 hval = NEXT (hval, ip); 235 hval = NEXT (hval, ip);
199 htab[IDX (hval)] = ip; 236 htab[IDX (hval)] = ip;
200 ip++; 237 ip++;
201
202#if VERY_FAST && !ULTRA_FAST
203 hval = NEXT (hval, ip);
204 htab[IDX (hval)] = ip;
205 ip++;
206#endif
207#else
208 do
209 {
210 hval = NEXT (hval, ip);
211 htab[IDX (hval)] = ip;
212 ip++;
213 } 238 }
214 while (len--); 239 while (len--);
215#endif 240#endif
241 lit = 0; op++; /* start run */
216 continue; 242 continue;
217 }
218 } 243 }
219 else if (expect_false (ip == in_end))
220 break;
221 244
222 /* one more literal byte we must copy */ 245 /* one more literal byte we must copy */
246
247 if (expect_false (op >= out_end))
248 return 0;
249
223 lit++; 250 lit++;
224 ip++; 251 *op++ = *ip++;
225 252
226 if (expect_false (lit == MAX_LIT)) 253 if (expect_false (lit == MAX_LIT))
227 { 254 {
228 if (op + 1 + MAX_LIT >= out_end) 255 op [- lit - 1] = lit - 1; /* stop run */
229 return 0; 256 lit = 0; op++; /* start run */
230
231 *op++ = MAX_LIT - 1;
232
233#ifdef lzf_movsb
234 ip -= lit;
235 lzf_movsb (op, ip, lit);
236#else
237 lit = -lit;
238 do
239 *op++ = ip[lit];
240 while (++lit);
241#endif
242 } 257 }
243 } 258 }
244 259
245 if (lit) 260 if (op + lit + 2 >= out_end)
261 return 0;
262
263 while (ip < in_end)
246 { 264 {
247 if (op + lit + 1 >= out_end) 265 lit++;
248 return 0;
249
250 *op++ = lit - 1; 266 *op++ = *ip++;
251#ifdef lzf_movsb
252 ip -= lit;
253 lzf_movsb (op, ip, lit);
254#else
255 lit = -lit;
256 do
257 *op++ = ip[lit];
258 while (++lit);
259#endif
260 } 267 }
261 268
269 op [- lit - 1] = lit - 1;
270
262 return op - (u8 *) out_data; 271 return op - (u8 *)out_data;
263} 272}
264 273

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