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/cvs/liblzf/lzf_c.c
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Comparing liblzf/lzf_c.c (file contents):
Revision 1.20 by root, Tue Nov 13 08:38:49 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 {
158 /* match found at *ref++ */
159 unsigned int len = 2;
160 unsigned int maxlen = in_end - ip - len;
161 maxlen = maxlen > MAX_REF ? MAX_REF : maxlen;
162
163 if (expect_false (op + 1 + 3 >= out_end))
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 }
193
194 do
195 len++;
196 while (len < maxlen && ref[len] == ip[len]);
197
198 break;
199 }
200
201 len -= 2;
202 ip++;
203
204 if (len < 7)
205 {
206 *op++ = (off >> 8) + (len << 5);
207 }
208 else
209 {
210 *op++ = (off >> 8) + ( 7 << 5);
211 *op++ = len - 7;
212 }
213
214 *op++ = off;
215
216#if ULTRA_FAST || VERY_FAST
217 ip += len;
218#if VERY_FAST && !ULTRA_FAST
219 --ip;
220#endif
221 hval = FRST (ip);
222
134 hval = NEXT (hval, ip); 223 hval = NEXT (hval, ip);
135 hslot = htab + IDX (hval); 224 htab[IDX (hval)] = ip;
136 ref = *hslot; *hslot = ip; 225 ip++;
137 226
138 if (1 227#if VERY_FAST && !ULTRA_FAST
139#if INIT_HTAB && !USE_MEMCPY 228 hval = NEXT (hval, ip);
140 && ref < ip /* the next test will actually take care of this, but this is faster */ 229 htab[IDX (hval)] = ip;
230 ip++;
141#endif 231#endif
142 && (off = ip - ref - 1) < MAX_OFF
143 && ip + 4 < in_end
144 && ref > (u8 *)in_data
145#if STRICT_ALIGN
146 x x x
147 && ref[0] == ip[0]
148 && ref[1] == ip[1]
149 && ref[2] == ip[2]
150#else 232#else
151 && *(u16 *)ref == *(u16 *)ip 233 do
152 && ref[2] == ip[2]
153#endif
154 ) 234 {
155 {
156 /* match found at *ref++ */
157 unsigned int len = 2;
158 unsigned int maxlen = in_end - ip - len;
159 maxlen = maxlen > MAX_REF ? MAX_REF : maxlen;
160
161 if (expect_false (op + lit + 1 + 3 >= out_end))
162 return 0;
163
164 if (expect_false (lit))
165 {
166 *op++ = lit - 1;
167 lit = -lit;
168 do
169 *op++ = ip[lit];
170 while (expect_false (++lit));
171 }
172
173 for (;;)
174 {
175 if (expect_true (maxlen > 16))
176 {
177 len++; if (ref [len] != ip [len]) break;
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 len++; if (ref [len] != ip [len]) break;
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 len++; if (ref [len] != ip [len]) break;
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 len++; if (ref [len] != ip [len]) break;
193 }
194
195 do
196 len++;
197 while (len < maxlen && ref[len] == ip[len]);
198
199 break;
200 }
201
202 len -= 2;
203 ip++;
204
205 if (len < 7)
206 {
207 *op++ = (off >> 8) + (len << 5);
208 }
209 else
210 {
211 *op++ = (off >> 8) + ( 7 << 5);
212 *op++ = len - 7;
213 }
214
215 *op++ = off;
216
217#if ULTRA_FAST || VERY_FAST
218 ip += len;
219#if VERY_FAST && !ULTRA_FAST
220 --ip;
221#endif
222 hval = FRST (ip);
223
224 hval = NEXT (hval, ip); 235 hval = NEXT (hval, ip);
225 htab[IDX (hval)] = ip; 236 htab[IDX (hval)] = ip;
226 ip++; 237 ip++;
227
228#if VERY_FAST && !ULTRA_FAST
229 hval = NEXT (hval, ip);
230 htab[IDX (hval)] = ip;
231 ip++;
232#endif
233#else
234 do
235 {
236 hval = NEXT (hval, ip);
237 htab[IDX (hval)] = ip;
238 ip++;
239 } 238 }
240 while (len--); 239 while (len--);
241#endif 240#endif
241 lit = 0; op++; /* start run */
242 continue; 242 continue;
243 }
244 } 243 }
245 else if (expect_false (ip == in_end))
246 break;
247 244
248 /* 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
249 lit++; 250 lit++;
250 ip++; 251 *op++ = *ip++;
251 252
252 if (expect_false (lit == MAX_LIT)) 253 if (expect_false (lit == MAX_LIT))
253 { 254 {
254 if (op + 1 + MAX_LIT >= out_end) 255 op [- lit - 1] = lit - 1; /* stop run */
255 return 0; 256 lit = 0; op++; /* start run */
256
257 *op++ = MAX_LIT - 1;
258
259#ifdef lzf_movsb
260 ip -= MAX_LIT;
261 lzf_movsb (op, ip, lit);
262#else
263 lit = -lit;
264 do
265 *op++ = ip[lit];
266 while (++lit);
267#endif
268 } 257 }
269 } 258 }
270 259
271 if (lit) 260 if (op + lit + 2 >= out_end)
261 return 0;
262
263 while (ip < in_end)
272 { 264 {
273 if (op + lit + 1 >= out_end) 265 lit++;
274 return 0;
275
276 *op++ = lit - 1; 266 *op++ = *ip++;
277#ifdef lzf_movsb
278 ip -= lit;
279 lzf_movsb (op, ip, lit);
280#else
281 lit = -lit;
282 do
283 *op++ = ip[lit];
284 while (++lit);
285#endif
286 } 267 }
287 268
269 op [- lit - 1] = lit - 1;
270
288 return op - (u8 *) out_data; 271 return op - (u8 *)out_data;
289} 272}
290 273

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