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root/radiance/ray/src/cv/mgflib/lookup.c
Revision: 1.11
Committed: Fri Nov 21 07:15:29 2003 UTC (20 years, 4 months ago) by greg
Content type: text/plain
Branch: MAIN
CVS Tags: rad3R7P1, rad4R0, rad3R6, rad3R6P1, rad3R8, rad3R9, rad3R7P2
Changes since 1.10: +1 -3 lines
Log Message:
Fixed prototyping in mkillum and eliminated compile error in lookup.c

File Contents

# Content
1 #ifndef lint
2 static const char RCSid[] = "$Id: lookup.c,v 1.10 2003/11/15 17:54:06 schorsch Exp $";
3 #endif
4 /*
5 * Table lookup routines
6 */
7
8 #include <stdio.h>
9 #include <stdlib.h>
10
11 #include "lookup.h"
12
13
14 int
15 lu_init(tbl, nel) /* initialize tbl for at least nel elements */
16 register LUTAB *tbl;
17 int nel;
18 {
19 static int hsiztab[] = {
20 31, 61, 127, 251, 509, 1021, 2039, 4093, 8191, 16381,
21 32749, 65521, 131071, 262139, 524287, 1048573, 2097143,
22 4194301, 8388593, 0
23 };
24 register int *hsp;
25
26 nel += nel>>1; /* 66% occupancy */
27 for (hsp = hsiztab; *hsp; hsp++)
28 if (*hsp > nel)
29 break;
30 if (!(tbl->tsiz = *hsp))
31 tbl->tsiz = nel*2 + 1; /* not always prime */
32 tbl->tabl = (LUENT *)calloc(tbl->tsiz, sizeof(LUENT));
33 if (tbl->tabl == NULL)
34 tbl->tsiz = 0;
35 tbl->ndel = 0;
36 return(tbl->tsiz);
37 }
38
39
40 unsigned long
41 lu_shash(s) /* hash a nul-terminated string */
42 char *s;
43 {
44 static unsigned char shuffle[256] = {
45 0, 157, 58, 215, 116, 17, 174, 75, 232, 133, 34,
46 191, 92, 249, 150, 51, 208, 109, 10, 167, 68, 225,
47 126, 27, 184, 85, 242, 143, 44, 201, 102, 3, 160,
48 61, 218, 119, 20, 177, 78, 235, 136, 37, 194, 95,
49 252, 153, 54, 211, 112, 13, 170, 71, 228, 129, 30,
50 187, 88, 245, 146, 47, 204, 105, 6, 163, 64, 221,
51 122, 23, 180, 81, 238, 139, 40, 197, 98, 255, 156,
52 57, 214, 115, 16, 173, 74, 231, 132, 33, 190, 91,
53 248, 149, 50, 207, 108, 9, 166, 67, 224, 125, 26,
54 183, 84, 241, 142, 43, 200, 101, 2, 159, 60, 217,
55 118, 19, 176, 77, 234, 135, 36, 193, 94, 251, 152,
56 53, 210, 111, 12, 169, 70, 227, 128, 29, 186, 87,
57 244, 145, 46, 203, 104, 5, 162, 63, 220, 121, 22,
58 179, 80, 237, 138, 39, 196, 97, 254, 155, 56, 213,
59 114, 15, 172, 73, 230, 131, 32, 189, 90, 247, 148,
60 49, 206, 107, 8, 165, 66, 223, 124, 25, 182, 83,
61 240, 141, 42, 199, 100, 1, 158, 59, 216, 117, 18,
62 175, 76, 233, 134, 35, 192, 93, 250, 151, 52, 209,
63 110, 11, 168, 69, 226, 127, 28, 185, 86, 243, 144,
64 45, 202, 103, 4, 161, 62, 219, 120, 21, 178, 79,
65 236, 137, 38, 195, 96, 253, 154, 55, 212, 113, 14,
66 171, 72, 229, 130, 31, 188, 89, 246, 147, 48, 205,
67 106, 7, 164, 65, 222, 123, 24, 181, 82, 239, 140,
68 41, 198, 99
69 };
70 register int i = 0;
71 register unsigned long h = 0;
72 register unsigned char *t = (unsigned char *)s;
73
74 while (*t)
75 h ^= (unsigned long)shuffle[*t++] << ((i+=11) & 0xf);
76
77 return(h);
78 }
79
80
81 LUENT *
82 lu_find(tbl, key) /* find a table entry */
83 register LUTAB *tbl;
84 char *key;
85 {
86 unsigned long hval;
87 int i, n;
88 register int ndx;
89 register LUENT *le;
90 /* look up object */
91 if (tbl->tsiz == 0 && !lu_init(tbl, 1))
92 return(NULL);
93 hval = (*tbl->hashf)(key);
94 tryagain:
95 ndx = hval % tbl->tsiz;
96 for (i = 0, n = 1; i < tbl->tsiz; i++, n += 2) {
97 le = &tbl->tabl[ndx];
98 if (le->key == NULL) {
99 le->hval = hval;
100 return(le);
101 }
102 if (le->hval == hval &&
103 (tbl->keycmp == NULL || !(*tbl->keycmp)(le->key, key))) {
104 return(le);
105 }
106 if ((ndx += n) >= tbl->tsiz) /* this happens rarely */
107 ndx = ndx % tbl->tsiz;
108 }
109 /* table is full, reallocate */
110 le = tbl->tabl;
111 ndx = tbl->tsiz;
112 i = tbl->ndel;
113 if (!lu_init(tbl, ndx-i+1)) { /* no more memory! */
114 tbl->tabl = le;
115 tbl->tsiz = ndx;
116 tbl->ndel = i;
117 return(NULL);
118 }
119 /*
120 * The following code may fail if the user has reclaimed many
121 * deleted entries and the system runs out of memory in a
122 * recursive call to lu_find().
123 */
124 while (ndx--)
125 if (le[ndx].key != NULL) {
126 if (le[ndx].data != NULL)
127 *lu_find(tbl,le[ndx].key) = le[ndx];
128 else if (tbl->freek != NULL)
129 (*tbl->freek)(le[ndx].key);
130 }
131 free((void *)le);
132 goto tryagain; /* should happen only once! */
133 }
134
135
136 void
137 lu_delete(tbl, key) /* delete a table entry */
138 register LUTAB *tbl;
139 char *key;
140 {
141 register LUENT *le;
142
143 if ((le = lu_find(tbl, key)) == NULL)
144 return;
145 if (le->key == NULL || le->data == NULL)
146 return;
147 if (tbl->freed != NULL)
148 (*tbl->freed)(le->data);
149 le->data = NULL;
150 tbl->ndel++;
151 }
152
153
154 int
155 lu_doall(tbl, f) /* loop through all valid table entries */
156 register LUTAB *tbl;
157 int (*f)(LUENT *);
158 {
159 int rval = 0;
160 register LUENT *tp;
161
162 for (tp = tbl->tabl + tbl->tsiz; tp-- > tbl->tabl; )
163 if (tp->data != NULL) {
164 if (f != NULL)
165 rval += (*f)(tp);
166 else
167 rval++;
168 }
169 return(rval);
170 }
171
172
173 void
174 lu_done(tbl) /* free table and contents */
175 register LUTAB *tbl;
176 {
177 register LUENT *tp;
178
179 if (!tbl->tsiz)
180 return;
181 for (tp = tbl->tabl + tbl->tsiz; tp-- > tbl->tabl; )
182 if (tp->key != NULL) {
183 if (tbl->freek != NULL)
184 (*tbl->freek)(tp->key);
185 if (tp->data != NULL && tbl->freed != NULL)
186 (*tbl->freed)(tp->data);
187 }
188 free((void *)tbl->tabl);
189 tbl->tabl = NULL;
190 tbl->tsiz = 0;
191 tbl->ndel = 0;
192 }