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Comparing Compress-LZF/lzf_c.c (file contents):
Revision 1.1 by root, Thu Sep 27 18:36:34 2001 UTC vs.
Revision 1.14 by root, Sun Aug 25 18:13:26 2013 UTC

1/* 1/*
2 * Copyright (c) 2000 Marc Alexander Lehmann <pcg@goof.com> 2 * Copyright (c) 2000-2010,2012 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 * 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 *
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-
21 * CIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, 18 * CIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
22 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; 19 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
23 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, 20 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
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.
24 *
25 * Alternatively, the contents of this file may be used under the terms of
26 * the GNU General Public License ("GPL") version 2 or any later version,
27 * in which case the provisions of the GPL are applicable instead of
28 * the above. If you wish to allow the use of your version of this file
29 * only under the terms of the GPL and not to allow others to use your
30 * version of this file under the BSD license, indicate your decision
31 * by deleting the provisions above and replace them with the notice
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
34 * either the BSD or the GPL.
27 */ 35 */
28 36
29#include "lzfP.h" 37#include "lzfP.h"
30 38
31#define HSIZE (1 << (HLOG)) 39#define HSIZE (1 << (HLOG))
32 40
33/* 41/*
34 * don't play with this unless you benchmark! 42 * don't play with this unless you benchmark!
35 * decompression is not dependent on the hash function 43 * the data format is not dependent on the hash function.
36 * the hashing function might seem strange, just believe me 44 * the hash function might seem strange, just believe me,
37 * it works ;) 45 * it works ;)
38 */ 46 */
47#ifndef FRST
39#define FRST(p) (((p[0]) << 8) + p[1]) 48# define FRST(p) (((p[0]) << 8) | p[1])
40#define NEXT(v,p) (((v) << 8) + p[2]) 49# define NEXT(v,p) (((v) << 8) | p[2])
50# if MULTIPLICATION_IS_SLOW
51# if ULTRA_FAST
52# define IDX(h) ((( h >> (3*8 - HLOG)) - h ) & (HSIZE - 1))
53# elif VERY_FAST
54# define IDX(h) ((( h >> (3*8 - HLOG)) - h*5) & (HSIZE - 1))
55# else
41#define IDX(h) ((((h ^ (h << 4)) >> (3*8 - HLOG)) + h*3) & (HSIZE - 1)) 56# define IDX(h) ((((h ^ (h << 5)) >> (3*8 - HLOG)) - h*5) & (HSIZE - 1))
42/* 57# endif
43 * IDX works because it is very similar to a multiplicative hash, e.g. 58# else
44 * (h * 57321 >> (3*8 - HLOG)) 59/* this one was developed with sesse,
45 * the next one is also quite good, albeit slow ;) 60 * and is very similar to the one in snappy.
46 * (int)(cos(h & 0xffffff) * 1e6) 61 * it does need a modern enough cpu with a fast multiplication.
47 */ 62 */
63# define IDX(h) (((h * 0x1e35a7bdU) >> (32 - HLOG - 8)) & (HSIZE - 1))
64# endif
65#endif
48 66
49#if 0 67#if 0
50/* original lzv-like hash function */ 68/* original lzv-like hash function, much worse and thus slower */
51# define FRST(p) (p[0] << 5) ^ p[1] 69# define FRST(p) (p[0] << 5) ^ p[1]
52# define NEXT(v,p) (v << 5) ^ p[2] 70# define NEXT(v,p) ((v) << 5) ^ p[2]
53# define IDX(h) (h) & (HSIZE - 1) 71# define IDX(h) ((h) & (HSIZE - 1))
54#endif 72#endif
55 73
56#define MAX_LIT (1 << 5) 74#define MAX_LIT (1 << 5)
57#define MAX_OFF (1 << 13) 75#define MAX_OFF (1 << 13)
58#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)
59 88
60/* 89/*
61 * compressed format 90 * compressed format
62 * 91 *
63 * 000LLLLL <L+1> ; literal 92 * 000LLLLL <L+1> ; literal, L+1=1..33 octets
64 * LLLOOOOO oooooooo ; backref L 93 * LLLooooo oooooooo ; backref L+1=1..7 octets, o+1=1..4096 offset
65 * 111OOOOO LLLLLLLL oooooooo ; backref L+7 94 * 111ooooo LLLLLLLL oooooooo ; backref L+8 octets, o+1=1..4096 offset
66 * 95 *
67 */ 96 */
68 97
69unsigned int 98unsigned int
70lzf_compress (const void *const in_data, unsigned int in_len, 99lzf_compress (const void *const in_data, unsigned int in_len,
71 void *out_data, unsigned int out_len) 100 void *out_data, unsigned int out_len
101#if LZF_STATE_ARG
102 , LZF_STATE htab
103#endif
104 )
72{ 105{
73 const u8 *htab[HSIZE]; 106#if !LZF_STATE_ARG
107 LZF_STATE htab;
108#endif
74 const u8 *ip = in_data; 109 const u8 *ip = (const u8 *)in_data;
75 u8 *op = out_data; 110 u8 *op = (u8 *)out_data;
76 const u8 *in_end = ip + in_len; 111 const u8 *in_end = ip + in_len;
77 u8 *out_end = op + out_len; 112 u8 *out_end = op + out_len;
78 const u8 *ref; 113 const u8 *ref;
79 114
80 unsigned int hval = FRST (ip); 115 /* off requires a type wide enough to hold a general pointer difference.
116 * ISO C doesn't have that (size_t might not be enough and ptrdiff_t only
117 * works for differences within a single object). We also assume that
118 * no bit pattern traps. Since the only platform that is both non-POSIX
119 * and fails to support both assumptions is windows 64 bit, we make a
120 * special workaround for it.
121 */
122#if defined (_WIN32) && defined (_M_X64)
123 /* workaround for missing POSIX compliance */
124 #if __GNUC__
125 unsigned long long off;
126 #else
127 unsigned __int64 off;
128 #endif
129#else
81 unsigned int off; 130 unsigned long off;
82 int lit = 0; 131#endif
132 unsigned int hval;
133 int lit;
134
135 if (!in_len || !out_len)
136 return 0;
83 137
84#if INIT_HTAB 138#if INIT_HTAB
85# if USE_MEMCPY
86 memset (htab, 0, sizeof (htab)); 139 memset (htab, 0, sizeof (htab));
140#endif
141
142 lit = 0; op++; /* start run */
143
144 hval = FRST (ip);
145 while (ip < in_end - 2)
146 {
147 LZF_HSLOT *hslot;
148
149 hval = NEXT (hval, ip);
150 hslot = htab + IDX (hval);
151 ref = *hslot + LZF_HSLOT_BIAS; *hslot = ip - LZF_HSLOT_BIAS;
152
153 if (1
154#if INIT_HTAB
155 && ref < ip /* the next test will actually take care of this, but this is faster */
156#endif
157 && (off = ip - ref - 1) < MAX_OFF
158 && ref > (u8 *)in_data
159 && ref[2] == ip[2]
160#if STRICT_ALIGN
161 && ((ref[1] << 8) | ref[0]) == ((ip[1] << 8) | ip[0])
87# else 162#else
88 for (off = 0; off < HSIZE; off++) 163 && *(u16 *)ref == *(u16 *)ip
89 htab[off] = ip; 164#endif
165 )
166 {
167 /* match found at *ref++ */
168 unsigned int len = 2;
169 unsigned int maxlen = in_end - ip - len;
170 maxlen = maxlen > MAX_REF ? MAX_REF : maxlen;
171
172 if (expect_false (op + 3 + 1 >= out_end)) /* first a faster conservative test */
173 if (op - !lit + 3 + 1 >= out_end) /* second the exact but rare test */
174 return 0;
175
176 op [- lit - 1] = lit - 1; /* stop run */
177 op -= !lit; /* undo run if length is zero */
178
179 for (;;)
180 {
181 if (expect_true (maxlen > 16))
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 len++; if (ref [len] != ip [len]) break;
194 len++; if (ref [len] != ip [len]) break;
195 len++; if (ref [len] != ip [len]) break;
196 len++; if (ref [len] != ip [len]) break;
197
198 len++; if (ref [len] != ip [len]) break;
199 len++; if (ref [len] != ip [len]) break;
200 len++; if (ref [len] != ip [len]) break;
201 len++; if (ref [len] != ip [len]) break;
202 }
203
204 do
205 len++;
206 while (len < maxlen && ref[len] == ip[len]);
207
208 break;
209 }
210
211 len -= 2; /* len is now #octets - 1 */
212 ip++;
213
214 if (len < 7)
215 {
216 *op++ = (off >> 8) + (len << 5);
217 }
218 else
219 {
220 *op++ = (off >> 8) + ( 7 << 5);
221 *op++ = len - 7;
222 }
223
224 *op++ = off;
225
226 lit = 0; op++; /* start run */
227
228 ip += len + 1;
229
230 if (expect_false (ip >= in_end - 2))
231 break;
232
233#if ULTRA_FAST || VERY_FAST
234 --ip;
235# if VERY_FAST && !ULTRA_FAST
236 --ip;
90# endif 237# endif
238 hval = FRST (ip);
239
240 hval = NEXT (hval, ip);
241 htab[IDX (hval)] = ip - LZF_HSLOT_BIAS;
242 ip++;
243
244# if VERY_FAST && !ULTRA_FAST
245 hval = NEXT (hval, ip);
246 htab[IDX (hval)] = ip - LZF_HSLOT_BIAS;
247 ip++;
91#endif 248# endif
249#else
250 ip -= len + 1;
92 251
93 do 252 do
253 {
254 hval = NEXT (hval, ip);
255 htab[IDX (hval)] = ip - LZF_HSLOT_BIAS;
256 ip++;
257 }
258 while (len--);
259#endif
260 }
261 else
262 {
263 /* one more literal byte we must copy */
264 if (expect_false (op >= out_end))
265 return 0;
266
267 lit++; *op++ = *ip++;
268
269 if (expect_false (lit == MAX_LIT))
270 {
271 op [- lit - 1] = lit - 1; /* stop run */
272 lit = 0; op++; /* start run */
273 }
274 }
275 }
276
277 if (op + 3 > out_end) /* at most 3 bytes can be missing here */
278 return 0;
279
280 while (ip < in_end)
94 { 281 {
95 hval = NEXT (hval, ip); 282 lit++; *op++ = *ip++;
96 off = IDX (hval);
97 ref = htab[off];
98 htab[off] = ip;
99 283
100 if (1 284 if (expect_false (lit == MAX_LIT))
101#if INIT_HTAB && !USE_MEMCPY 285 {
102 && ref < ip /* the next test will actually take care of this, but it is faster */ 286 op [- lit - 1] = lit - 1; /* stop run */
103#endif 287 lit = 0; op++; /* start run */
104 && (off = ip - ref - 1) < MAX_OFF 288 }
105 && ip + 4 < in_end
106 && ref > (u8 *)in_data
107#if STRICT_ALIGN
108 && ref[0] == ip[0]
109 && ref[1] == ip[1]
110 && ref[2] == ip[2]
111#else
112 && *(u16 *)ref == *(u16 *)ip
113 && ref[2] == ip[2]
114#endif
115 )
116 {
117 /* match found at *ref++ */
118 unsigned int len = 2;
119 unsigned int maxlen = in_end - ip - len;
120 maxlen = maxlen > MAX_REF ? MAX_REF : maxlen;
121
122 do
123 len++;
124 while (len < maxlen && ref[len] == ip[len]);
125
126 if (op + lit + 1 + 3 >= out_end)
127 return 0;
128
129 if (lit)
130 {
131 *op++ = lit - 1;
132 lit = -lit;
133 do
134 *op++ = ip[lit];
135 while (++lit);
136 }
137
138 len -= 2;
139 ip++;
140
141 if (len < 7)
142 {
143 *op++ = (off >> 8) + (len << 5);
144 }
145 else
146 {
147 *op++ = (off >> 8) + ( 7 << 5);
148 *op++ = len - 7;
149 }
150
151 *op++ = off;
152
153#if ULTRA_FAST
154 ip += len;
155 hval = FRST (ip);
156 hval = NEXT (hval, ip);
157 htab[IDX (hval)] = ip;
158 ip++;
159#else
160 do
161 {
162 hval = NEXT (hval, ip);
163 htab[IDX (hval)] = ip;
164 ip++;
165 }
166 while (len--);
167#endif
168 }
169 else
170 {
171 /* one more literal byte we must copy */
172 lit++;
173 ip++;
174
175 if (lit == MAX_LIT)
176 {
177 if (op + 1 + MAX_LIT >= out_end)
178 return 0;
179
180 *op++ = MAX_LIT - 1;
181#if USE_MEMCPY
182 memcpy (op, ip - MAX_LIT, MAX_LIT);
183 op += MAX_LIT;
184 lit = 0;
185#else
186 lit = -lit;
187 do
188 *op++ = ip[lit];
189 while (++lit);
190#endif
191 }
192 }
193 } 289 }
194 while (ip < in_end);
195 290
196 if (lit) 291 op [- lit - 1] = lit - 1; /* end run */
197 { 292 op -= !lit; /* undo run if length is zero */
198 if (op + lit + 1 >= out_end)
199 return 0;
200 293
201 *op++ = lit - 1;
202 lit = -lit;
203 do
204 *op++ = ip[lit];
205 while (++lit);
206 }
207
208 return op - (u8 *) out_data; 294 return op - (u8 *)out_data;
209} 295}
296

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