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Comparing liblzf/lzf_c.c (file contents):
Revision 1.11 by root, Fri Feb 16 22:13:43 2007 UTC vs.
Revision 1.22 by root, Tue Nov 13 10:41:52 2007 UTC

1/* 1/*
2 * Copyright (c) 2000-2005 Marc Alexander Lehmann <schmorp@schmorp.de> 2 * Copyright (c) 2000-2007 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,
8 * this list of conditions and the following disclaimer. 8 * this list of conditions and the following disclaimer.
9 * 9 *
10 * 2. Redistributions in binary form must reproduce the above copyright 10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the 11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution. 12 * documentation and/or other materials provided with the distribution.
13 *
14 * 3. The name of the author may not be used to endorse or promote products
15 * derived from this software without specific prior written permission.
16 * 13 *
17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED 14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
18 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MER- 15 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MER-
19 * CHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO 16 * CHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
20 * EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPE- 17 * EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPE-
… …
24 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTH- 21 * 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 22 * ERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
26 * OF THE POSSIBILITY OF SUCH DAMAGE. 23 * OF THE POSSIBILITY OF SUCH DAMAGE.
27 * 24 *
28 * Alternatively, the contents of this file may be used under the terms of 25 * 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 26 * the GNU General Public License ("GPL") version 2 or any later version,
30 * provisions of the GPL are applicable instead of the above. If you wish to 27 * in which case the provisions of the GPL are applicable instead of
31 * allow the use of your version of this file only under the terms of the 28 * the above. If you wish to allow the use of your version of this file
32 * GPL and not to allow others to use your version of this file under the 29 * only under the terms of the GPL and not to allow others to use your
33 * BSD license, indicate your decision by deleting the provisions above and 30 * version of this file under the BSD license, indicate your decision
34 * replace them with the notice and other provisions required by the GPL. If 31 * by deleting the provisions above and replace them with the notice
35 * you do not delete the provisions above, a recipient may use your version 32 * and other provisions required by the GPL. If you do not delete the
33 * provisions above, a recipient may use your version of this file under
36 * of this file under either the BSD or the GPL. 34 * either the BSD or the GPL.
37 */ 35 */
38 36
39#include "lzfP.h" 37#include "lzfP.h"
40 38
41#define HSIZE (1 << (HLOG)) 39#define HSIZE (1 << (HLOG))
… …
47 * it works ;) 45 * it works ;)
48 */ 46 */
49#ifndef FRST 47#ifndef FRST
50# define FRST(p) (((p[0]) << 8) | p[1]) 48# define FRST(p) (((p[0]) << 8) | p[1])
51# 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
52# 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
57/*# define IDX(h) ((ip[0] * 121 ^ ip[1] * 33 ^ ip[2] * 1) & (HSIZE-1))*/
53#endif 58#endif
54/* 59/*
55 * 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.
56 * ((h * 57321 >> (3*8 - HLOG)) & (HSIZE - 1)) 61 * ((h * 57321 >> (3*8 - HLOG)) & (HSIZE - 1))
57 * the latter is also quite fast on newer CPUs, and sligthly better 62 * the latter is also quite fast on newer CPUs, and compresses similarly.
58 * 63 *
59 * the next one is also quite good, albeit slow ;) 64 * the next one is also quite good, albeit slow ;)
60 * (int)(cos(h & 0xffffff) * 1e6) 65 * (int)(cos(h & 0xffffff) * 1e6)
61 */ 66 */
62 67
… …
67# define IDX(h) ((h) & (HSIZE - 1)) 72# define IDX(h) ((h) & (HSIZE - 1))
68#endif 73#endif
69 74
70#define MAX_LIT (1 << 5) 75#define MAX_LIT (1 << 5)
71#define MAX_OFF (1 << 13) 76#define MAX_OFF (1 << 13)
72#define MAX_REF ((1 << 8) + (1 << 3)) 77#define MAX_REF ((1 << 8) + (1 << 3))
78
79#if __GNUC__ >= 3
80# define expect(expr,value) __builtin_expect ((expr),(value))
81# define inline inline
82#else
83# define expect(expr,value) (expr)
84# define inline static
85#endif
86
87#define expect_false(expr) expect ((expr) != 0, 0)
88#define expect_true(expr) expect ((expr) != 0, 1)
73 89
74/* 90/*
75 * compressed format 91 * compressed format
76 * 92 *
77 * 000LLLLL <L+1> ; literal 93 * 000LLLLL <L+1> ; literal
… …
96 u8 *op = (u8 *)out_data; 112 u8 *op = (u8 *)out_data;
97 const u8 *in_end = ip + in_len; 113 const u8 *in_end = ip + in_len;
98 u8 *out_end = op + out_len; 114 u8 *out_end = op + out_len;
99 const u8 *ref; 115 const u8 *ref;
100 116
101 unsigned int hval = FRST (ip); 117 unsigned int hval;
102 unsigned long off; 118 unsigned long off;
103 int lit = 0; 119 int lit;
120
121 if (!in_len || !out_len)
122 return 0;
104 123
105#if INIT_HTAB 124#if INIT_HTAB
106# if USE_MEMCPY
107 memset (htab, 0, sizeof (htab)); 125 memset (htab, 0, sizeof (htab));
108# else 126# if 0
109 for (hslot = htab; hslot < htab + HSIZE; hslot++) 127 for (hslot = htab; hslot < htab + HSIZE; hslot++)
110 *hslot++ = ip; 128 *hslot++ = ip;
111# endif 129# endif
112#endif 130#endif
113 131
114 for (;;) 132 lit = 0; op++; /* start run */
133
134 hval = FRST (ip);
135 while (ip < in_end - 2)
115 { 136 {
116 if (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 )
117 { 157 {
118 hval = NEXT (hval, ip);
119 hslot = htab + IDX (hval);
120 ref = *hslot; *hslot = ip;
121
122 if (1
123#if INIT_HTAB && !USE_MEMCPY
124 && ref < ip /* the next test will actually take care of this, but this is faster */
125#endif
126 && (off = ip - ref - 1) < MAX_OFF
127 && ip + 4 < in_end
128 && ref > (u8 *)in_data
129#if STRICT_ALIGN
130 && ref[0] == ip[0]
131 && ref[1] == ip[1]
132 && ref[2] == ip[2]
133#else
134 && *(u16 *)ref == *(u16 *)ip
135 && ref[2] == ip[2]
136#endif
137 )
138 {
139 /* match found at *ref++ */ 158 /* match found at *ref++ */
140 unsigned int len = 2; 159 unsigned int len = 2;
141 unsigned int maxlen = in_end - ip - len; 160 unsigned int maxlen = in_end - ip - len;
142 maxlen = maxlen > MAX_REF ? MAX_REF : maxlen; 161 maxlen = maxlen > MAX_REF ? MAX_REF : maxlen;
143 162
144 if (op + lit + 1 + 3 >= out_end) 163 if (expect_false (op + 1 + 3 >= out_end))
145 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 }
146 193
147 do 194 do
148 len++; 195 len++;
149 while (len < maxlen && ref[len] == ip[len]); 196 while (len < maxlen && ref[len] == ip[len]);
150 197
151 if (lit)
152 { 198 break;
153 *op++ = lit - 1;
154 lit = -lit;
155 do
156 *op++ = ip[lit];
157 while (++lit);
158 } 199 }
159 200
160 len -= 2; 201 len -= 2;
161 ip++; 202 ip++;
162 203
163 if (len < 7) 204 if (len < 7)
164 { 205 {
165 *op++ = (off >> 8) + (len << 5); 206 *op++ = (off >> 8) + (len << 5);
166 } 207 }
167 else 208 else
168 { 209 {
169 *op++ = (off >> 8) + ( 7 << 5); 210 *op++ = (off >> 8) + ( 7 << 5);
170 *op++ = len - 7; 211 *op++ = len - 7;
171 } 212 }
172 213
173 *op++ = off; 214 *op++ = off;
174 215
175#if ULTRA_FAST || VERY_FAST 216#if ULTRA_FAST || VERY_FAST
176 ip += len; 217 ip += len;
177#if VERY_FAST && !ULTRA_FAST 218#if VERY_FAST && !ULTRA_FAST
178 --ip; 219 --ip;
179#endif 220#endif
180 hval = FRST (ip); 221 hval = FRST (ip);
181 222
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 {
182 hval = NEXT (hval, ip); 235 hval = NEXT (hval, ip);
183 htab[IDX (hval)] = ip; 236 htab[IDX (hval)] = ip;
184 ip++; 237 ip++;
185
186#if VERY_FAST && !ULTRA_FAST
187 hval = NEXT (hval, ip);
188 htab[IDX (hval)] = ip;
189 ip++;
190#endif
191#else
192 do
193 {
194 hval = NEXT (hval, ip);
195 htab[IDX (hval)] = ip;
196 ip++;
197 } 238 }
198 while (len--); 239 while (len--);
199#endif 240#endif
241 lit = 0; op++; /* start run */
200 continue; 242 continue;
201 }
202 } 243 }
203 else if (ip == in_end)
204 break;
205 244
206 /* 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
207 lit++; 250 lit++;
208 ip++; 251 *op++ = *ip++;
209 252
210 if (lit == MAX_LIT) 253 if (expect_false (lit == MAX_LIT))
211 { 254 {
212 if (op + 1 + MAX_LIT >= out_end) 255 op [- lit - 1] = lit - 1; /* stop run */
213 return 0; 256 lit = 0; op++; /* start run */
214
215 *op++ = MAX_LIT - 1;
216#if USE_MEMCPY
217 memcpy (op, ip - MAX_LIT, MAX_LIT);
218 op += MAX_LIT;
219 lit = 0;
220#else
221 lit = -lit;
222 do
223 *op++ = ip[lit];
224 while (++lit);
225#endif
226 } 257 }
227 } 258 }
228 259
229 if (lit) 260 if (op + lit + 2 >= out_end)
261 return 0;
262
263 while (ip < in_end)
230 { 264 {
231 if (op + lit + 1 >= out_end) 265 lit++;
232 return 0;
233
234 *op++ = lit - 1; 266 *op++ = *ip++;
235 lit = -lit;
236 do
237 *op++ = ip[lit];
238 while (++lit);
239 } 267 }
240 268
269 op [- lit - 1] = lit - 1;
270
241 return op - (u8 *) out_data; 271 return op - (u8 *)out_data;
242} 272}
273

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