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/cvs/liblzf/lzf_c.c
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Comparing liblzf/lzf_c.c (file contents):
Revision 1.15 by root, Fri Nov 2 12:39:20 2007 UTC vs.
Revision 1.22 by root, Tue Nov 13 10:41:52 2007 UTC

… …
21 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTH- 21 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTH-
22 * 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
23 * OF THE POSSIBILITY OF SUCH DAMAGE. 23 * OF THE POSSIBILITY OF SUCH DAMAGE.
24 * 24 *
25 * 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
26 * 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,
27 * 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
28 * 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
29 * 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
30 * BSD license, indicate your decision by deleting the provisions above and 30 * version of this file under the BSD license, indicate your decision
31 * 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
32 * 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
33 * of this file under either the BSD or the GPL. 34 * either the BSD or the GPL.
34 */ 35 */
35 36
36#include "lzfP.h" 37#include "lzfP.h"
37 38
38#define HSIZE (1 << (HLOG)) 39#define HSIZE (1 << (HLOG))
… …
44 * it works ;) 45 * it works ;)
45 */ 46 */
46#ifndef FRST 47#ifndef FRST
47# define FRST(p) (((p[0]) << 8) | p[1]) 48# define FRST(p) (((p[0]) << 8) | p[1])
48# 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
49# 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
50/*# define IDX(h) ((ip[0] * 121 ^ ip[1] * 33 ^ ip[2] * 1) & (HSIZE-1))*/ 57/*# define IDX(h) ((ip[0] * 121 ^ ip[1] * 33 ^ ip[2] * 1) & (HSIZE-1))*/
51#endif 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)) & (HSIZE - 1)) 61 * ((h * 57321 >> (3*8 - HLOG)) & (HSIZE - 1))
… …
67 74
68#define MAX_LIT (1 << 5) 75#define MAX_LIT (1 << 5)
69#define MAX_OFF (1 << 13) 76#define MAX_OFF (1 << 13)
70#define MAX_REF ((1 << 8) + (1 << 3)) 77#define MAX_REF ((1 << 8) + (1 << 3))
71 78
72#if (__i386 || __amd64) && __GNUC__ >= 3 79#if __GNUC__ >= 3
73# define lzf_movsb(dst, src, len) \ 80# define expect(expr,value) __builtin_expect ((expr),(value))
74 asm ("rep movsb" \ 81# define inline inline
75 : "=D" (dst), "=S" (src), "=c" (len) \ 82#else
76 : "0" (dst), "1" (src), "2" (len)); 83# define expect(expr,value) (expr)
84# define inline static
77#endif 85#endif
86
87#define expect_false(expr) expect ((expr) != 0, 0)
88#define expect_true(expr) expect ((expr) != 0, 1)
78 89
79/* 90/*
80 * compressed format 91 * compressed format
81 * 92 *
82 * 000LLLLL <L+1> ; literal 93 * 000LLLLL <L+1> ; literal
… …
101 u8 *op = (u8 *)out_data; 112 u8 *op = (u8 *)out_data;
102 const u8 *in_end = ip + in_len; 113 const u8 *in_end = ip + in_len;
103 u8 *out_end = op + out_len; 114 u8 *out_end = op + out_len;
104 const u8 *ref; 115 const u8 *ref;
105 116
106 unsigned int hval = FRST (ip); 117 unsigned int hval;
107 unsigned long off; 118 unsigned long off;
108 int lit = 0; 119 int lit;
120
121 if (!in_len || !out_len)
122 return 0;
109 123
110#if INIT_HTAB 124#if INIT_HTAB
111 memset (htab, 0, sizeof (htab)); 125 memset (htab, 0, sizeof (htab));
112# if 0 126# if 0
113 for (hslot = htab; hslot < htab + HSIZE; hslot++) 127 for (hslot = htab; hslot < htab + HSIZE; hslot++)
114 *hslot++ = ip; 128 *hslot++ = ip;
115# endif 129# endif
116#endif 130#endif
117 131
118 for (;;) 132 lit = 0; op++; /* start run */
133
134 hval = FRST (ip);
135 while (ip < in_end - 2)
119 { 136 {
120 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 )
121 { 157 {
122 hval = NEXT (hval, ip);
123 hslot = htab + IDX (hval);
124 ref = *hslot; *hslot = ip;
125
126 if (1
127#if INIT_HTAB && !USE_MEMCPY
128 && ref < ip /* the next test will actually take care of this, but this is faster */
129#endif
130 && (off = ip - ref - 1) < MAX_OFF
131 && ip + 4 < in_end
132 && ref > (u8 *)in_data
133#if STRICT_ALIGN
134 && ref[0] == ip[0]
135 && ref[1] == ip[1]
136 && ref[2] == ip[2]
137#else
138 && *(u16 *)ref == *(u16 *)ip
139 && ref[2] == ip[2]
140#endif
141 )
142 {
143 /* match found at *ref++ */ 158 /* match found at *ref++ */
144 unsigned int len = 2; 159 unsigned int len = 2;
145 unsigned int maxlen = in_end - ip - len; 160 unsigned int maxlen = in_end - ip - len;
146 maxlen = maxlen > MAX_REF ? MAX_REF : maxlen; 161 maxlen = maxlen > MAX_REF ? MAX_REF : maxlen;
147 162
148 if (op + lit + 1 + 3 >= out_end) 163 if (expect_false (op + 1 + 3 >= out_end))
149 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 }
150 193
151 do 194 do
152 len++; 195 len++;
153 while (len < maxlen && ref[len] == ip[len]); 196 while (len < maxlen && ref[len] == ip[len]);
154 197
155 if (lit)
156 { 198 break;
157 *op++ = lit - 1;
158 lit = -lit;
159 do
160 *op++ = ip[lit];
161 while (++lit);
162 } 199 }
163 200
164 len -= 2; 201 len -= 2;
165 ip++; 202 ip++;
166 203
167 if (len < 7) 204 if (len < 7)
168 { 205 {
169 *op++ = (off >> 8) + (len << 5); 206 *op++ = (off >> 8) + (len << 5);
170 } 207 }
171 else 208 else
172 { 209 {
173 *op++ = (off >> 8) + ( 7 << 5); 210 *op++ = (off >> 8) + ( 7 << 5);
174 *op++ = len - 7; 211 *op++ = len - 7;
175 } 212 }
176 213
177 *op++ = off; 214 *op++ = off;
178 215
179#if ULTRA_FAST || VERY_FAST 216#if ULTRA_FAST || VERY_FAST
180 ip += len; 217 ip += len;
181#if VERY_FAST && !ULTRA_FAST 218#if VERY_FAST && !ULTRA_FAST
182 --ip; 219 --ip;
183#endif 220#endif
184 hval = FRST (ip); 221 hval = FRST (ip);
185 222
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 {
186 hval = NEXT (hval, ip); 235 hval = NEXT (hval, ip);
187 htab[IDX (hval)] = ip; 236 htab[IDX (hval)] = ip;
188 ip++; 237 ip++;
189
190#if VERY_FAST && !ULTRA_FAST
191 hval = NEXT (hval, ip);
192 htab[IDX (hval)] = ip;
193 ip++;
194#endif
195#else
196 do
197 {
198 hval = NEXT (hval, ip);
199 htab[IDX (hval)] = ip;
200 ip++;
201 } 238 }
202 while (len--); 239 while (len--);
203#endif 240#endif
241 lit = 0; op++; /* start run */
204 continue; 242 continue;
205 }
206 } 243 }
207 else if (ip == in_end)
208 break;
209 244
210 /* 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
211 lit++; 250 lit++;
212 ip++; 251 *op++ = *ip++;
213 252
214 if (lit == MAX_LIT) 253 if (expect_false (lit == MAX_LIT))
215 { 254 {
216 if (op + 1 + MAX_LIT >= out_end) 255 op [- lit - 1] = lit - 1; /* stop run */
217 return 0; 256 lit = 0; op++; /* start run */
218
219 *op++ = MAX_LIT - 1;
220
221#ifdef lzf_movsb
222 ip -= lit;
223 lzf_movsb (op, ip, lit);
224#else
225 lit = -lit;
226 do
227 *op++ = ip[lit];
228 while (++lit);
229#endif
230 } 257 }
231 } 258 }
232 259
233 if (lit) 260 if (op + lit + 2 >= out_end)
261 return 0;
262
263 while (ip < in_end)
234 { 264 {
235 if (op + lit + 1 >= out_end) 265 lit++;
236 return 0;
237
238 *op++ = lit - 1; 266 *op++ = *ip++;
239#ifdef lzf_movsb
240 ip -= lit;
241 lzf_movsb (op, ip, lit);
242#else
243 lit = -lit;
244 do
245 *op++ = ip[lit];
246 while (++lit);
247#endif
248 } 267 }
249 268
269 op [- lit - 1] = lit - 1;
270
250 return op - (u8 *) out_data; 271 return op - (u8 *)out_data;
251} 272}
252 273

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