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Comparing liblzf/lzf_c.c (file contents):
Revision 1.7 by root, Tue Aug 3 15:37:48 2004 UTC vs.
Revision 1.23 by root, Tue Nov 13 10:48:02 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*5) & (HSIZE - 1)) 55# define IDX(h) ((((h ^ (h << 5)) >> (3*8 - HLOG)) - h*5) & (HSIZE - 1))
56# endif
57#endif
52/* 58/*
53 * IDX works because it is very similar to a multiplicative hash, e.g. 59 * IDX works because it is very similar to a multiplicative hash, e.g.
54 * ((h * 57321 >> (3*8 - HLOG)) & (HSIZE - 1)) 60 * ((h * 57321 >> (3*8 - HLOG)) & (HSIZE - 1))
55 * the latter is also quite fast on newer CPUs, and sligthly better 61 * the latter is also quite fast on newer CPUs, and compresses similarly.
56 * 62 *
57 * the next one is also quite good, albeit slow ;) 63 * the next one is also quite good, albeit slow ;)
58 * (int)(cos(h & 0xffffff) * 1e6) 64 * (int)(cos(h & 0xffffff) * 1e6)
59 */ 65 */
60 66
… …
65# define IDX(h) ((h) & (HSIZE - 1)) 71# define IDX(h) ((h) & (HSIZE - 1))
66#endif 72#endif
67 73
68#define MAX_LIT (1 << 5) 74#define MAX_LIT (1 << 5)
69#define MAX_OFF (1 << 13) 75#define MAX_OFF (1 << 13)
70#define MAX_REF ((1 << 8) + (1 << 3)) 76#define MAX_REF ((1 << 8) + (1 << 3))
77
78#if __GNUC__ >= 3
79# define expect(expr,value) __builtin_expect ((expr),(value))
80# define inline inline
81#else
82# define expect(expr,value) (expr)
83# define inline static
84#endif
85
86#define expect_false(expr) expect ((expr) != 0, 0)
87#define expect_true(expr) expect ((expr) != 0, 1)
71 88
72/* 89/*
73 * compressed format 90 * compressed format
74 * 91 *
75 * 000LLLLL <L+1> ; literal 92 * 000LLLLL <L+1> ; literal
76 * LLLOOOOO oooooooo ; backref L 93 * LLLooooo oooooooo ; backref L
77 * 111OOOOO LLLLLLLL oooooooo ; backref L+7 94 * 111ooooo LLLLLLLL oooooooo ; backref L+7
78 * 95 *
79 */ 96 */
80 97
81unsigned int 98unsigned int
82lzf_compress (const void *const in_data, unsigned int in_len, 99lzf_compress (const void *const in_data, unsigned int in_len,
83 void *out_data, unsigned int out_len 100 void *out_data, unsigned int out_len
84#if LZF_STATE_ARG 101#if LZF_STATE_ARG
85 , LZF_STATE *htab 102 , LZF_STATE htab
86#endif 103#endif
87 ) 104 )
88{ 105{
89#if !LZF_STATE_ARG 106#if !LZF_STATE_ARG
90 LZF_STATE htab; 107 LZF_STATE htab;
… …
94 u8 *op = (u8 *)out_data; 111 u8 *op = (u8 *)out_data;
95 const u8 *in_end = ip + in_len; 112 const u8 *in_end = ip + in_len;
96 u8 *out_end = op + out_len; 113 u8 *out_end = op + out_len;
97 const u8 *ref; 114 const u8 *ref;
98 115
99 unsigned int hval = FRST (ip); 116 unsigned int hval;
100 unsigned long off; 117 unsigned long off;
101 int lit = 0; 118 int lit;
119
120 if (!in_len || !out_len)
121 return 0;
102 122
103#if INIT_HTAB 123#if INIT_HTAB
104# if USE_MEMCPY
105 memset (htab, 0, sizeof (htab)); 124 memset (htab, 0, sizeof (htab));
106# else 125# if 0
107 for (hslot = htab; hslot < htab + HSIZE; hslot++) 126 for (hslot = htab; hslot < htab + HSIZE; hslot++)
108 *hslot++ = ip; 127 *hslot++ = ip;
109# endif 128# endif
110#endif 129#endif
111 130
112 for (;;) 131 lit = 0; op++; /* start run */
132
133 hval = FRST (ip);
134 while (ip < in_end - 2)
113 { 135 {
114 if (ip < in_end - 2) 136 hval = NEXT (hval, ip);
137 hslot = htab + IDX (hval);
138 ref = *hslot; *hslot = ip;
139
140 if (1
141#if INIT_HTAB && !USE_MEMCPY
142 && ref < ip /* the next test will actually take care of this, but this is faster */
143#endif
144 && (off = ip - ref - 1) < MAX_OFF
145 && ip + 4 < in_end
146 && ref > (u8 *)in_data
147#if STRICT_ALIGN
148 && ref[0] == ip[0]
149 && ref[1] == ip[1]
150 && ref[2] == ip[2]
151#else
152 && *(u16 *)ref == *(u16 *)ip
153 && ref[2] == ip[2]
154#endif
155 )
115 { 156 {
116 hval = NEXT (hval, ip);
117 hslot = htab + IDX (hval);
118 ref = *hslot; *hslot = ip;
119
120 if (1
121#if INIT_HTAB && !USE_MEMCPY
122 && ref < ip /* the next test will actually take care of this, but this is faster */
123#endif
124 && (off = ip - ref - 1) < MAX_OFF
125 && ip + 4 < in_end
126 && ref > (u8 *)in_data
127#if STRICT_ALIGN
128 && ref[0] == ip[0]
129 && ref[1] == ip[1]
130 && ref[2] == ip[2]
131#else
132 && *(u16 *)ref == *(u16 *)ip
133 && ref[2] == ip[2]
134#endif
135 )
136 {
137 /* match found at *ref++ */ 157 /* match found at *ref++ */
138 unsigned int len = 2; 158 unsigned int len = 2;
139 unsigned int maxlen = in_end - ip - len; 159 unsigned int maxlen = in_end - ip - len;
140 maxlen = maxlen > MAX_REF ? MAX_REF : maxlen; 160 maxlen = maxlen > MAX_REF ? MAX_REF : maxlen;
161
162 if (expect_false (op + 1 + 3 >= out_end))
163 return 0;
164
165 op [- lit - 1] = lit - 1; /* stop run */
166 op -= !lit; /* undo run if length is zero */
167
168 for (;;)
169 {
170 if (expect_true (maxlen > 16))
171 {
172 len++; if (ref [len] != ip [len]) break;
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
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
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
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 }
141 192
142 do 193 do
143 len++; 194 len++;
144 while (len < maxlen && ref[len] == ip[len]); 195 while (len < maxlen && ref[len] == ip[len]);
145 196
146 if (op + lit + 1 + 3 >= out_end)
147 return 0;
148
149 if (lit)
150 { 197 break;
151 *op++ = lit - 1;
152 lit = -lit;
153 do
154 *op++ = ip[lit];
155 while (++lit);
156 } 198 }
157 199
158 len -= 2; 200 len -= 2;
159 ip++; 201 ip++;
160 202
161 if (len < 7) 203 if (len < 7)
162 { 204 {
163 *op++ = (off >> 8) + (len << 5); 205 *op++ = (off >> 8) + (len << 5);
164 } 206 }
165 else 207 else
166 { 208 {
167 *op++ = (off >> 8) + ( 7 << 5); 209 *op++ = (off >> 8) + ( 7 << 5);
168 *op++ = len - 7; 210 *op++ = len - 7;
169 } 211 }
170 212
171 *op++ = off; 213 *op++ = off;
172 214
173#if ULTRA_FAST 215#if ULTRA_FAST || VERY_FAST
174 ip += len; 216 ip += len;
217#if VERY_FAST && !ULTRA_FAST
218 --ip;
219#endif
175 hval = FRST (ip); 220 hval = FRST (ip);
221
222 hval = NEXT (hval, ip);
223 htab[IDX (hval)] = ip;
224 ip++;
225
226#if VERY_FAST && !ULTRA_FAST
227 hval = NEXT (hval, ip);
228 htab[IDX (hval)] = ip;
229 ip++;
230#endif
231#else
232 do
233 {
176 hval = NEXT (hval, ip); 234 hval = NEXT (hval, ip);
177 htab[IDX (hval)] = ip; 235 htab[IDX (hval)] = ip;
178 ip++; 236 ip++;
179#else
180 do
181 {
182 hval = NEXT (hval, ip);
183 htab[IDX (hval)] = ip;
184 ip++;
185 } 237 }
186 while (len--); 238 while (len--);
187#endif 239#endif
240 lit = 0; op++; /* start run */
188 continue; 241 continue;
189 }
190 } 242 }
191 else if (ip == in_end)
192 break;
193 243
194 /* one more literal byte we must copy */ 244 /* one more literal byte we must copy */
245
246 if (expect_false (op >= out_end))
247 return 0;
248
195 lit++; 249 lit++;
196 ip++; 250 *op++ = *ip++;
197 251
198 if (lit == MAX_LIT) 252 if (expect_false (lit == MAX_LIT))
199 { 253 {
200 if (op + 1 + MAX_LIT >= out_end) 254 op [- lit - 1] = lit - 1; /* stop run */
201 return 0; 255 lit = 0; op++; /* start run */
202
203 *op++ = MAX_LIT - 1;
204#if USE_MEMCPY
205 memcpy (op, ip - MAX_LIT, MAX_LIT);
206 op += MAX_LIT;
207 lit = 0;
208#else
209 lit = -lit;
210 do
211 *op++ = ip[lit];
212 while (++lit);
213#endif
214 } 256 }
215 } 257 }
216 258
217 if (lit) 259 if (op + lit + 2 >= out_end)
260 return 0;
261
262 while (ip < in_end)
218 { 263 {
219 if (op + lit + 1 >= out_end) 264 lit++;
220 return 0;
221
222 *op++ = lit - 1; 265 *op++ = *ip++;
223 lit = -lit;
224 do
225 *op++ = ip[lit];
226 while (++lit);
227 } 266 }
228 267
268 op [- lit - 1] = lit - 1;
269
229 return op - (u8 *) out_data; 270 return op - (u8 *)out_data;
230} 271}
272

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