ViewVC Help
View File | Revision Log | Show Annotations | Download File
/cvs/liblzf/lzf_c.c
(Generate patch)

Comparing liblzf/lzf_c.c (file contents):
Revision 1.6 by pcg, Tue Apr 20 18:11:58 2004 UTC vs.
Revision 1.22 by root, Tue Nov 13 10:41:52 2007 UTC

1/* 1/*
2 * Copyright (c) 2000-2003 Marc Alexander Lehmann <pcg@goof.com> 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))
… …
44 * don't play with this unless you benchmark! 42 * don't play with this unless you benchmark!
45 * decompression is not dependent on the hash function 43 * decompression is not dependent on the hash function
46 * the hashing function might seem strange, just believe me 44 * the hashing function might seem strange, just believe me
47 * it works ;) 45 * it works ;)
48 */ 46 */
47#ifndef FRST
49#define FRST(p) (((p[0]) << 8) + p[1]) 48# define FRST(p) (((p[0]) << 8) | p[1])
50#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
51#define IDX(h) ((((h ^ (h << 5)) >> (3*8 - HLOG)) + h*3) & (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))*/
58#endif
52/* 59/*
53 * 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.
54 * (h * 57321 >> (3*8 - HLOG)) 61 * ((h * 57321 >> (3*8 - HLOG)) & (HSIZE - 1))
62 * the latter is also quite fast on newer CPUs, and compresses similarly.
63 *
55 * the next one is also quite good, albeit slow ;) 64 * the next one is also quite good, albeit slow ;)
56 * (int)(cos(h & 0xffffff) * 1e6) 65 * (int)(cos(h & 0xffffff) * 1e6)
57 */ 66 */
58 67
59#if 0 68#if 0
60/* original lzv-like hash function */ 69/* original lzv-like hash function, much worse and thus slower */
61# define FRST(p) (p[0] << 5) ^ p[1] 70# define FRST(p) (p[0] << 5) ^ p[1]
62# define NEXT(v,p) ((v) << 5) ^ p[2] 71# define NEXT(v,p) ((v) << 5) ^ p[2]
63# define IDX(h) ((h) & (HSIZE - 1)) 72# define IDX(h) ((h) & (HSIZE - 1))
64#endif 73#endif
65 74
66#define MAX_LIT (1 << 5) 75#define MAX_LIT (1 << 5)
67#define MAX_OFF (1 << 13) 76#define MAX_OFF (1 << 13)
68#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)
69 89
70/* 90/*
71 * compressed format 91 * compressed format
72 * 92 *
73 * 000LLLLL <L+1> ; literal 93 * 000LLLLL <L+1> ; literal
74 * LLLOOOOO oooooooo ; backref L 94 * LLLooooo oooooooo ; backref L
75 * 111OOOOO LLLLLLLL oooooooo ; backref L+7 95 * 111ooooo LLLLLLLL oooooooo ; backref L+7
76 * 96 *
77 */ 97 */
78 98
79unsigned int 99unsigned int
80lzf_compress (const void *const in_data, unsigned int in_len, 100lzf_compress (const void *const in_data, unsigned int in_len,
81 void *out_data, unsigned int out_len 101 void *out_data, unsigned int out_len
82#if LZF_STATE_ARG 102#if LZF_STATE_ARG
83 , LZF_STATE *htab 103 , LZF_STATE htab
84#endif 104#endif
85 ) 105 )
86{ 106{
87#if !LZF_STATE_ARG 107#if !LZF_STATE_ARG
88 LZF_STATE htab; 108 LZF_STATE htab;
… …
92 u8 *op = (u8 *)out_data; 112 u8 *op = (u8 *)out_data;
93 const u8 *in_end = ip + in_len; 113 const u8 *in_end = ip + in_len;
94 u8 *out_end = op + out_len; 114 u8 *out_end = op + out_len;
95 const u8 *ref; 115 const u8 *ref;
96 116
97 unsigned int hval = FRST (ip); 117 unsigned int hval;
98 unsigned long off; 118 unsigned long off;
99 int lit = 0; 119 int lit;
120
121 if (!in_len || !out_len)
122 return 0;
100 123
101#if INIT_HTAB 124#if INIT_HTAB
102# if USE_MEMCPY
103 memset (htab, 0, sizeof (htab)); 125 memset (htab, 0, sizeof (htab));
104# else 126# if 0
105 for (hslot = htab; hslot < htab + HSIZE; hslot++) 127 for (hslot = htab; hslot < htab + HSIZE; hslot++)
106 *hslot++ = ip; 128 *hslot++ = ip;
107# endif 129# endif
108#endif 130#endif
109 131
110 for (;;) 132 lit = 0; op++; /* start run */
133
134 hval = FRST (ip);
135 while (ip < in_end - 2)
111 { 136 {
112 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 )
113 { 157 {
114 hval = NEXT (hval, ip);
115 hslot = htab + IDX (hval);
116 ref = *hslot; *hslot = ip;
117
118 if (1
119#if INIT_HTAB && !USE_MEMCPY
120 && ref < ip /* the next test will actually take care of this, but this is faster */
121#endif
122 && (off = ip - ref - 1) < MAX_OFF
123 && ip + 4 < in_end
124 && ref > (u8 *)in_data
125#if STRICT_ALIGN
126 && ref[0] == ip[0]
127 && ref[1] == ip[1]
128 && ref[2] == ip[2]
129#else
130 && *(u16 *)ref == *(u16 *)ip
131 && ref[2] == ip[2]
132#endif
133 )
134 {
135 /* match found at *ref++ */ 158 /* match found at *ref++ */
136 unsigned int len = 2; 159 unsigned int len = 2;
137 unsigned int maxlen = in_end - ip - len; 160 unsigned int maxlen = in_end - ip - len;
138 maxlen = maxlen > MAX_REF ? MAX_REF : maxlen; 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 }
139 193
140 do 194 do
141 len++; 195 len++;
142 while (len < maxlen && ref[len] == ip[len]); 196 while (len < maxlen && ref[len] == ip[len]);
143 197
144 if (op + lit + 1 + 3 >= out_end)
145 return 0;
146
147 if (lit)
148 { 198 break;
149 *op++ = lit - 1;
150 lit = -lit;
151 do
152 *op++ = ip[lit];
153 while (++lit);
154 } 199 }
155 200
156 len -= 2; 201 len -= 2;
157 ip++; 202 ip++;
158 203
159 if (len < 7) 204 if (len < 7)
160 { 205 {
161 *op++ = (off >> 8) + (len << 5); 206 *op++ = (off >> 8) + (len << 5);
162 } 207 }
163 else 208 else
164 { 209 {
165 *op++ = (off >> 8) + ( 7 << 5); 210 *op++ = (off >> 8) + ( 7 << 5);
166 *op++ = len - 7; 211 *op++ = len - 7;
167 } 212 }
168 213
169 *op++ = off; 214 *op++ = off;
170 215
171#if ULTRA_FAST 216#if ULTRA_FAST || VERY_FAST
172 ip += len; 217 ip += len;
218#if VERY_FAST && !ULTRA_FAST
219 --ip;
220#endif
173 hval = FRST (ip); 221 hval = FRST (ip);
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 {
174 hval = NEXT (hval, ip); 235 hval = NEXT (hval, ip);
175 htab[IDX (hval)] = ip; 236 htab[IDX (hval)] = ip;
176 ip++; 237 ip++;
177#else
178 do
179 {
180 hval = NEXT (hval, ip);
181 htab[IDX (hval)] = ip;
182 ip++;
183 } 238 }
184 while (len--); 239 while (len--);
185#endif 240#endif
241 lit = 0; op++; /* start run */
186 continue; 242 continue;
187 }
188 } 243 }
189 else if (ip == in_end)
190 break;
191 244
192 /* 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
193 lit++; 250 lit++;
194 ip++; 251 *op++ = *ip++;
195 252
196 if (lit == MAX_LIT) 253 if (expect_false (lit == MAX_LIT))
197 { 254 {
198 if (op + 1 + MAX_LIT >= out_end) 255 op [- lit - 1] = lit - 1; /* stop run */
199 return 0; 256 lit = 0; op++; /* start run */
200
201 *op++ = MAX_LIT - 1;
202#if USE_MEMCPY
203 memcpy (op, ip - MAX_LIT, MAX_LIT);
204 op += MAX_LIT;
205 lit = 0;
206#else
207 lit = -lit;
208 do
209 *op++ = ip[lit];
210 while (++lit);
211#endif
212 } 257 }
213 } 258 }
214 259
215 if (lit) 260 if (op + lit + 2 >= out_end)
261 return 0;
262
263 while (ip < in_end)
216 { 264 {
217 if (op + lit + 1 >= out_end) 265 lit++;
218 return 0;
219
220 *op++ = lit - 1; 266 *op++ = *ip++;
221 lit = -lit;
222 do
223 *op++ = ip[lit];
224 while (++lit);
225 } 267 }
226 268
269 op [- lit - 1] = lit - 1;
270
227 return op - (u8 *) out_data; 271 return op - (u8 *)out_data;
228} 272}
273

Diff Legend

– Removed lines
+ Added lines
< Changed lines
> Changed lines