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Comparing liblzf/lzf_c.c (file contents):
Revision 1.3 by root, Sun Nov 17 11:39:26 2002 UTC vs.
Revision 1.13 by root, Tue Jun 19 21:25:07 2007 UTC

1/* 1/*
2 * Copyright (c) 2000-2002 Marc Alexander Lehmann <pcg@goof.com> 2 * Copyright (c) 2000-2005 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,
… …
22 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; 22 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
23 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, 23 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
24 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTH- 24 * 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 25 * ERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
26 * OF THE POSSIBILITY OF SUCH DAMAGE. 26 * OF THE POSSIBILITY OF SUCH DAMAGE.
27 *
28 * 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
30 * provisions of the GPL are applicable instead of the above. If you wish to
31 * allow the use of your version of this file only under the terms of the
32 * GPL and not to allow others to use your version of this file under the
33 * BSD license, indicate your decision by deleting the provisions above and
34 * replace them with the notice and other provisions required by the GPL. If
35 * you do not delete the provisions above, a recipient may use your version
36 * of this file under either the BSD or the GPL.
27 */ 37 */
28 38
29#include "lzfP.h" 39#include "lzfP.h"
30 40
31#define HSIZE (1 << (HLOG)) 41#define HSIZE (1 << (HLOG))
… …
34 * don't play with this unless you benchmark! 44 * don't play with this unless you benchmark!
35 * decompression is not dependent on the hash function 45 * decompression is not dependent on the hash function
36 * the hashing function might seem strange, just believe me 46 * the hashing function might seem strange, just believe me
37 * it works ;) 47 * it works ;)
38 */ 48 */
49#ifndef FRST
39#define FRST(p) (((p[0]) << 8) + p[1]) 50# define FRST(p) (((p[0]) << 8) | p[1])
40#define NEXT(v,p) (((v) << 8) + p[2]) 51# define NEXT(v,p) (((v) << 8) | p[2])
41#define IDX(h) ((((h ^ (h << 5)) >> (3*8 - HLOG)) + h*3) & (HSIZE - 1)) 52# define IDX(h) ((((h ^ (h << 5)) >> (3*8 - HLOG)) - h*5) & (HSIZE - 1))
53/*# define IDX(h) ((ip[0] * 121 ^ ip[1] * 33 ^ ip[2] * 1) & (HSIZE-1))*/
54#endif
42/* 55/*
43 * IDX works because it is very similar to a multiplicative hash, e.g. 56 * IDX works because it is very similar to a multiplicative hash, e.g.
44 * (h * 57321 >> (3*8 - HLOG)) 57 * ((h * 57321 >> (3*8 - HLOG)) & (HSIZE - 1))
58 * the latter is also quite fast on newer CPUs, and compresses similarly.
59 *
45 * the next one is also quite good, albeit slow ;) 60 * the next one is also quite good, albeit slow ;)
46 * (int)(cos(h & 0xffffff) * 1e6) 61 * (int)(cos(h & 0xffffff) * 1e6)
47 */ 62 */
48 63
49#if 0 64#if 0
50/* original lzv-like hash function */ 65/* original lzv-like hash function, much worse and thus slower */
51# define FRST(p) (p[0] << 5) ^ p[1] 66# define FRST(p) (p[0] << 5) ^ p[1]
52# define NEXT(v,p) ((v) << 5) ^ p[2] 67# define NEXT(v,p) ((v) << 5) ^ p[2]
53# define IDX(h) ((h) & (HSIZE - 1)) 68# define IDX(h) ((h) & (HSIZE - 1))
54#endif 69#endif
55 70
56#define MAX_LIT (1 << 5) 71#define MAX_LIT (1 << 5)
57#define MAX_OFF (1 << 13) 72#define MAX_OFF (1 << 13)
58#define MAX_REF ((1 << 8) + (1 << 3)) 73#define MAX_REF ((1 << 8) + (1 << 3))
59 74
60/* 75/*
61 * compressed format 76 * compressed format
62 * 77 *
63 * 000LLLLL <L+1> ; literal 78 * 000LLLLL <L+1> ; literal
64 * LLLOOOOO oooooooo ; backref L 79 * LLLooooo oooooooo ; backref L
65 * 111OOOOO LLLLLLLL oooooooo ; backref L+7 80 * 111ooooo LLLLLLLL oooooooo ; backref L+7
66 * 81 *
67 */ 82 */
68 83
69unsigned int 84unsigned int
70lzf_compress (const void *const in_data, unsigned int in_len, 85lzf_compress (const void *const in_data, unsigned int in_len,
71 void *out_data, unsigned int out_len) 86 void *out_data, unsigned int out_len
87#if LZF_STATE_ARG
88 , LZF_STATE htab
89#endif
90 )
72{ 91{
73 const u8 *htab[HSIZE]; 92#if !LZF_STATE_ARG
93 LZF_STATE htab;
94#endif
74 const u8 **hslot; 95 const u8 **hslot;
75 const u8 *ip = in_data; 96 const u8 *ip = (const u8 *)in_data;
76 u8 *op = out_data; 97 u8 *op = (u8 *)out_data;
77 const u8 *in_end = ip + in_len; 98 const u8 *in_end = ip + in_len;
78 u8 *out_end = op + out_len; 99 u8 *out_end = op + out_len;
79 const u8 *ref; 100 const u8 *ref;
80 101
81 unsigned int hval = FRST (ip); 102 unsigned int hval = FRST (ip);
… …
89 for (hslot = htab; hslot < htab + HSIZE; hslot++) 110 for (hslot = htab; hslot < htab + HSIZE; hslot++)
90 *hslot++ = ip; 111 *hslot++ = ip;
91# endif 112# endif
92#endif 113#endif
93 114
94 do 115 for (;;)
95 { 116 {
117 if (ip < in_end - 2)
118 {
96 hval = NEXT (hval, ip); 119 hval = NEXT (hval, ip);
97 hslot = htab + IDX (hval); 120 hslot = htab + IDX (hval);
98 ref = *hslot; *hslot = ip; 121 ref = *hslot; *hslot = ip;
99 122
100 if (1 123 if (1
101#if INIT_HTAB && !USE_MEMCPY 124#if INIT_HTAB && !USE_MEMCPY
102 && ref < ip /* the next test will actually take care of this, but it is faster */ 125 && ref < ip /* the next test will actually take care of this, but this is faster */
103#endif 126#endif
104 && (off = ip - ref - 1) < MAX_OFF 127 && (off = ip - ref - 1) < MAX_OFF
105 && ip + 4 < in_end 128 && ip + 4 < in_end
106 && ref > (u8 *)in_data 129 && ref > (u8 *)in_data
107#if STRICT_ALIGN 130#if STRICT_ALIGN
108 && ref[0] == ip[0] 131 && ref[0] == ip[0]
109 && ref[1] == ip[1] 132 && ref[1] == ip[1]
110 && ref[2] == ip[2] 133 && ref[2] == ip[2]
111#else 134#else
112 && *(u16 *)ref == *(u16 *)ip 135 && *(u16 *)ref == *(u16 *)ip
113 && ref[2] == ip[2] 136 && ref[2] == ip[2]
114#endif 137#endif
115 ) 138 )
116 { 139 {
117 /* match found at *ref++ */ 140 /* match found at *ref++ */
118 unsigned int len = 2; 141 unsigned int len = 2;
119 unsigned int maxlen = in_end - ip - len; 142 unsigned int maxlen = in_end - ip - len;
120 maxlen = maxlen > MAX_REF ? MAX_REF : maxlen; 143 maxlen = maxlen > MAX_REF ? MAX_REF : maxlen;
121 144
122 do 145 if (op + lit + 1 + 3 >= out_end)
123 len++; 146 return 0;
147
148 do
149 len++;
124 while (len < maxlen && ref[len] == ip[len]); 150 while (len < maxlen && ref[len] == ip[len]);
125 151
126 if (op + lit + 1 + 3 >= out_end) 152 if (lit)
127 return 0; 153 {
128
129 if (lit)
130 {
131 *op++ = lit - 1; 154 *op++ = lit - 1;
132 lit = -lit; 155 lit = -lit;
133 do 156 do
134 *op++ = ip[lit]; 157 *op++ = ip[lit];
135 while (++lit); 158 while (++lit);
136 } 159 }
137 160
138 len -= 2; 161 len -= 2;
139 ip++; 162 ip++;
140 163
141 if (len < 7) 164 if (len < 7)
142 { 165 {
143 *op++ = (off >> 8) + (len << 5); 166 *op++ = (off >> 8) + (len << 5);
144 } 167 }
145 else 168 else
146 { 169 {
147 *op++ = (off >> 8) + ( 7 << 5); 170 *op++ = (off >> 8) + ( 7 << 5);
148 *op++ = len - 7; 171 *op++ = len - 7;
149 } 172 }
150 173
151 *op++ = off; 174 *op++ = off;
152 175
153#if ULTRA_FAST 176#if ULTRA_FAST || VERY_FAST
154 ip += len; 177 ip += len;
178#if VERY_FAST && !ULTRA_FAST
179 --ip;
180#endif
155 hval = FRST (ip); 181 hval = FRST (ip);
182
156 hval = NEXT (hval, ip); 183 hval = NEXT (hval, ip);
157 htab[IDX (hval)] = ip; 184 htab[IDX (hval)] = ip;
158 ip++; 185 ip++;
186
187#if VERY_FAST && !ULTRA_FAST
188 hval = NEXT (hval, ip);
189 htab[IDX (hval)] = ip;
190 ip++;
191#endif
159#else 192#else
160 do 193 do
161 { 194 {
162 hval = NEXT (hval, ip); 195 hval = NEXT (hval, ip);
163 htab[IDX (hval)] = ip; 196 htab[IDX (hval)] = ip;
197 ip++;
198 }
199 while (len--);
200#endif
201 continue;
202 }
203 }
204 else if (ip == in_end)
205 break;
206
207 /* one more literal byte we must copy */
208 lit++;
164 ip++; 209 ip++;
165 }
166 while (len--);
167#endif
168 }
169 else
170 {
171 /* one more literal byte we must copy */
172 lit++;
173 ip++;
174 210
175 if (lit == MAX_LIT) 211 if (lit == MAX_LIT)
176 { 212 {
177 if (op + 1 + MAX_LIT >= out_end) 213 if (op + 1 + MAX_LIT >= out_end)
178 return 0; 214 return 0;
179 215
180 *op++ = MAX_LIT - 1; 216 *op++ = MAX_LIT - 1;
181#if USE_MEMCPY 217#if USE_MEMCPY
182 memcpy (op, ip - MAX_LIT, MAX_LIT); 218 memcpy (op, ip - MAX_LIT, MAX_LIT);
183 op += MAX_LIT; 219 op += MAX_LIT;
184 lit = 0; 220 lit = 0;
185#else 221#else
186 lit = -lit; 222 lit = -lit;
187 do 223 do
188 *op++ = ip[lit]; 224 *op++ = ip[lit];
189 while (++lit); 225 while (++lit);
190#endif 226#endif
191 } 227 }
192 }
193 } 228 }
194 while (ip < in_end);
195 229
196 if (lit) 230 if (lit)
197 { 231 {
198 if (op + lit + 1 >= out_end) 232 if (op + lit + 1 >= out_end)
199 return 0; 233 return 0;

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