src/common/lookup.c

#ifndef lint
static const char       RCSid[] = "$Id: lookup.c,v 2.9 2003/06/30 14:59:11 schorsch Exp $";
#endif
/*
 * Table lookup routines
 */

#include "copyright.h"

#include <stdio.h>
#include <stdlib.h>

#include "lookup.h"


int
lu_init(tbl, nel)               /* initialize tbl for at least nel elements */
register LUTAB  *tbl;
int     nel;
{
        static int  hsiztab[] = {
                31, 61, 127, 251, 509, 1021, 2039, 4093, 8191, 16381, 
                32749, 65521, 131071, 262139, 524287, 1048573, 2097143, 
                4194301, 8388593, 0
        };
        register int  *hsp;

        nel += nel>>1;                  /* 66% occupancy */
        for (hsp = hsiztab; *hsp; hsp++)
                if (*hsp > nel)
                        break;
        if (!(tbl->tsiz = *hsp))
                tbl->tsiz = nel*2 + 1;          /* not always prime */
        tbl->tabl = (LUENT *)calloc(tbl->tsiz, sizeof(LUENT));
        if (tbl->tabl == NULL)
                tbl->tsiz = 0;
        tbl->ndel = 0;
        return(tbl->tsiz);
}


unsigned long
lu_shash(s)                     /* hash a nul-terminated string */
char    *s;
{
        static unsigned char shuffle[256] = {
                0, 157, 58, 215, 116, 17, 174, 75, 232, 133, 34,
                191, 92, 249, 150, 51, 208, 109, 10, 167, 68, 225,
                126, 27, 184, 85, 242, 143, 44, 201, 102, 3, 160,
                61, 218, 119, 20, 177, 78, 235, 136, 37, 194, 95,
                252, 153, 54, 211, 112, 13, 170, 71, 228, 129, 30,
                187, 88, 245, 146, 47, 204, 105, 6, 163, 64, 221,
                122, 23, 180, 81, 238, 139, 40, 197, 98, 255, 156,
                57, 214, 115, 16, 173, 74, 231, 132, 33, 190, 91,
                248, 149, 50, 207, 108, 9, 166, 67, 224, 125, 26,
                183, 84, 241, 142, 43, 200, 101, 2, 159, 60, 217,
                118, 19, 176, 77, 234, 135, 36, 193, 94, 251, 152,
                53, 210, 111, 12, 169, 70, 227, 128, 29, 186, 87,
                244, 145, 46, 203, 104, 5, 162, 63, 220, 121, 22,
                179, 80, 237, 138, 39, 196, 97, 254, 155, 56, 213,
                114, 15, 172, 73, 230, 131, 32, 189, 90, 247, 148,
                49, 206, 107, 8, 165, 66, 223, 124, 25, 182, 83,
                240, 141, 42, 199, 100, 1, 158, 59, 216, 117, 18,
                175, 76, 233, 134, 35, 192, 93, 250, 151, 52, 209,
                110, 11, 168, 69, 226, 127, 28, 185, 86, 243, 144,
                45, 202, 103, 4, 161, 62, 219, 120, 21, 178, 79,
                236, 137, 38, 195, 96, 253, 154, 55, 212, 113, 14,
                171, 72, 229, 130, 31, 188, 89, 246, 147, 48, 205,
                106, 7, 164, 65, 222, 123, 24, 181, 82, 239, 140,
                41, 198, 99
        };
        register int    i = 0;
        register unsigned long  h = 0;
        register unsigned char *t = (unsigned char *)s;

        while (*t)
                h ^= (unsigned long)shuffle[*t++] << ((i+=11) & 0xf);

        return(h);
}


LUENT *
lu_find(tbl, key)               /* find a table entry */
register LUTAB  *tbl;
char    *key;
{
        unsigned long   hval;
        int     i, n;
        register int    ndx;
        register LUENT  *le;
                                        /* look up object */
        if (tbl->tsiz == 0 && !lu_init(tbl, 1))
                return(NULL);
        hval = (*tbl->hashf)(key);
tryagain:
        ndx = hval % tbl->tsiz;
        for (i = 0, n = 1; i < tbl->tsiz; i++, n += 2) {
                le = &tbl->tabl[ndx];
                if (le->key == NULL) {
                        le->hval = hval;
                        return(le);
                }
                if (le->hval == hval && 
                      (tbl->keycmp == NULL || !(*tbl->keycmp)(le->key, key))) {
                        return(le);
                }
                if ((ndx += n) >= tbl->tsiz)    /* this happens rarely */
                        ndx = ndx % tbl->tsiz;
        }
                                        /* table is full, reallocate */
        le = tbl->tabl;
        ndx = tbl->tsiz;
        i = tbl->ndel;
        if (!lu_init(tbl, ndx-i+1)) {   /* no more memory! */
                tbl->tabl = le;
                tbl->tsiz = ndx;
                tbl->ndel = i;
                return(NULL);
        }
        /*
         * The following code may fail if the user has reclaimed many
         * deleted entries and the system runs out of memory in a
         * recursive call to lu_find().
         */
        while (ndx--)
                if (le[ndx].key != NULL) {
                        if (le[ndx].data != NULL)
                                *lu_find(tbl,le[ndx].key) = le[ndx];
                        else if (tbl->freek != NULL)
                                (*tbl->freek)(le[ndx].key);
                }
        free((void *)le);
        goto tryagain;                  /* should happen only once! */
}


void
lu_delete(tbl, key)             /* delete a table entry */
register LUTAB  *tbl;
char    *key;
{
        register LUENT  *le;

        if ((le = lu_find(tbl, key)) == NULL)
                return;
        if (le->key == NULL || le->data == NULL)
                return;
        if (tbl->freed != NULL)
                (*tbl->freed)(le->data);
        le->data = NULL;
        tbl->ndel++;
}


int
lu_doall(tbl, f)                /* loop through all valid table entries */
register LUTAB  *tbl;
int     (*f)();
{
        int     rval = 0;
        register LUENT  *tp;

        for (tp = tbl->tabl + tbl->tsiz; tp-- > tbl->tabl; )
                if (tp->data != NULL) {
                        if (f != NULL)
                                rval += (*f)(tp);
                        else
                                rval++;
                }
        return(rval);
}


void
lu_done(tbl)                    /* free table and contents */
register LUTAB  *tbl;
{
        register LUENT  *tp;

        if (!tbl->tsiz)
                return;
        for (tp = tbl->tabl + tbl->tsiz; tp-- > tbl->tabl; )
                if (tp->key != NULL) {
                        if (tbl->freek != NULL)
                                (*tbl->freek)(tp->key);
                        if (tp->data != NULL && tbl->freed != NULL)
                                (*tbl->freed)(tp->data);
                }
        free((void *)tbl->tabl);
        tbl->tabl = NULL;
        tbl->tsiz = 0;
        tbl->ndel = 0;
}
Revision:	2.10
Committed:	Mon Jul 21 22:30:17 2003 UTC (20 years, 9 months ago) by schorsch
Content type:	text/plain
Branch:	MAIN
Changes since 2.9:	+6 -11 lines
Log Message:	Eliminated copystruct() macro, which is unnecessary in ANSI. Reduced ambiguity warnings for nested if/if/else clauses.
#	Content
1	#ifndef lint
2	static const char RCSid[] = "$Id: lookup.c,v 2.9 2003/06/30 14:59:11 schorsch Exp $";
3	#endif
4	/*
5	* Table lookup routines
6	*/
7
8	#include "copyright.h"
9
10	#include <stdio.h>
11	#include <stdlib.h>
12
13	#include "lookup.h"
14
15
16	int
17	lu_init(tbl, nel) /* initialize tbl for at least nel elements */
18	register LUTAB *tbl;
19	int nel;
20	{
21	static int hsiztab[] = {
22	31, 61, 127, 251, 509, 1021, 2039, 4093, 8191, 16381,
23	32749, 65521, 131071, 262139, 524287, 1048573, 2097143,
24	4194301, 8388593, 0
25	};
26	register int *hsp;
27
28	nel += nel>>1; /* 66% occupancy */
29	for (hsp = hsiztab; *hsp; hsp++)
30	if (*hsp > nel)
31	break;
32	if (!(tbl->tsiz = *hsp))
33	tbl->tsiz = nel2 + 1; / not always prime */
34	tbl->tabl = (LUENT *)calloc(tbl->tsiz, sizeof(LUENT));
35	if (tbl->tabl == NULL)
36	tbl->tsiz = 0;
37	tbl->ndel = 0;
38	return(tbl->tsiz);
39	}
40
41
42	unsigned long
43	lu_shash(s) /* hash a nul-terminated string */
44	char *s;
45	{
46	static unsigned char shuffle[256] = {
47	0, 157, 58, 215, 116, 17, 174, 75, 232, 133, 34,
48	191, 92, 249, 150, 51, 208, 109, 10, 167, 68, 225,
49	126, 27, 184, 85, 242, 143, 44, 201, 102, 3, 160,
50	61, 218, 119, 20, 177, 78, 235, 136, 37, 194, 95,
51	252, 153, 54, 211, 112, 13, 170, 71, 228, 129, 30,
52	187, 88, 245, 146, 47, 204, 105, 6, 163, 64, 221,
53	122, 23, 180, 81, 238, 139, 40, 197, 98, 255, 156,
54	57, 214, 115, 16, 173, 74, 231, 132, 33, 190, 91,
55	248, 149, 50, 207, 108, 9, 166, 67, 224, 125, 26,
56	183, 84, 241, 142, 43, 200, 101, 2, 159, 60, 217,
57	118, 19, 176, 77, 234, 135, 36, 193, 94, 251, 152,
58	53, 210, 111, 12, 169, 70, 227, 128, 29, 186, 87,
59	244, 145, 46, 203, 104, 5, 162, 63, 220, 121, 22,
60	179, 80, 237, 138, 39, 196, 97, 254, 155, 56, 213,
61	114, 15, 172, 73, 230, 131, 32, 189, 90, 247, 148,
62	49, 206, 107, 8, 165, 66, 223, 124, 25, 182, 83,
63	240, 141, 42, 199, 100, 1, 158, 59, 216, 117, 18,
64	175, 76, 233, 134, 35, 192, 93, 250, 151, 52, 209,
65	110, 11, 168, 69, 226, 127, 28, 185, 86, 243, 144,
66	45, 202, 103, 4, 161, 62, 219, 120, 21, 178, 79,
67	236, 137, 38, 195, 96, 253, 154, 55, 212, 113, 14,
68	171, 72, 229, 130, 31, 188, 89, 246, 147, 48, 205,
69	106, 7, 164, 65, 222, 123, 24, 181, 82, 239, 140,
70	41, 198, 99
71	};
72	register int i = 0;
73	register unsigned long h = 0;
74	register unsigned char t = (unsigned char )s;
75
76	while (*t)
77	h ^= (unsigned long)shuffle[*t++] << ((i+=11) & 0xf);
78
79	return(h);
80	}
81
82
83	LUENT *
84	lu_find(tbl, key) /* find a table entry */
85	register LUTAB *tbl;
86	char *key;
87	{
88	unsigned long hval;
89	int i, n;
90	register int ndx;
91	register LUENT *le;
92	/* look up object */
93	if (tbl->tsiz == 0 && !lu_init(tbl, 1))
94	return(NULL);
95	hval = (*tbl->hashf)(key);
96	tryagain:
97	ndx = hval % tbl->tsiz;
98	for (i = 0, n = 1; i < tbl->tsiz; i++, n += 2) {
99	le = &tbl->tabl[ndx];
100	if (le->key == NULL) {
101	le->hval = hval;
102	return(le);
103	}
104	if (le->hval == hval &&
105	(tbl->keycmp == NULL \|\| !(*tbl->keycmp)(le->key, key))) {
106	return(le);
107	}
108	if ((ndx += n) >= tbl->tsiz) /* this happens rarely */
109	ndx = ndx % tbl->tsiz;
110	}
111	/* table is full, reallocate */
112	le = tbl->tabl;
113	ndx = tbl->tsiz;
114	i = tbl->ndel;
115	if (!lu_init(tbl, ndx-i+1)) { /* no more memory! */
116	tbl->tabl = le;
117	tbl->tsiz = ndx;
118	tbl->ndel = i;
119	return(NULL);
120	}
121	/*
122	* The following code may fail if the user has reclaimed many
123	* deleted entries and the system runs out of memory in a
124	* recursive call to lu_find().
125	*/
126	while (ndx--)
127	if (le[ndx].key != NULL) {
128	if (le[ndx].data != NULL)
129	*lu_find(tbl,le[ndx].key) = le[ndx];
130	else if (tbl->freek != NULL)
131	(*tbl->freek)(le[ndx].key);
132	}
133	free((void *)le);
134	goto tryagain; /* should happen only once! */
135	}
136
137
138	void
139	lu_delete(tbl, key) /* delete a table entry */
140	register LUTAB *tbl;
141	char *key;
142	{
143	register LUENT *le;
144
145	if ((le = lu_find(tbl, key)) == NULL)
146	return;
147	if (le->key == NULL \|\| le->data == NULL)
148	return;
149	if (tbl->freed != NULL)
150	(*tbl->freed)(le->data);
151	le->data = NULL;
152	tbl->ndel++;
153	}
154
155
156	int
157	lu_doall(tbl, f) /* loop through all valid table entries */
158	register LUTAB *tbl;
159	int (*f)();
160	{
161	int rval = 0;
162	register LUENT *tp;
163
164	for (tp = tbl->tabl + tbl->tsiz; tp-- > tbl->tabl; )
165	if (tp->data != NULL) {
166	if (f != NULL)
167	rval += (*f)(tp);
168	else
169	rval++;
170	}
171	return(rval);
172	}
173
174
175	void
176	lu_done(tbl) /* free table and contents */
177	register LUTAB *tbl;
178	{
179	register LUENT *tp;
180
181	if (!tbl->tsiz)
182	return;
183	for (tp = tbl->tabl + tbl->tsiz; tp-- > tbl->tabl; )
184	if (tp->key != NULL) {
185	if (tbl->freek != NULL)
186	(*tbl->freek)(tp->key);
187	if (tp->data != NULL && tbl->freed != NULL)
188	(*tbl->freed)(tp->data);
189	}
190	free((void *)tbl->tabl);
191	tbl->tabl = NULL;
192	tbl->tsiz = 0;
193	tbl->ndel = 0;
194	}