src/common/lookup.c

#ifndef lint
static const char       RCSid[] = "$Id: lookup.c,v 2.8 2003/05/13 17:58:32 greg Exp $";
#endif
/*
 * Table lookup routines
 */

#include "copyright.h"

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

#include "lookup.h"

#ifdef  NOSTRUCTASS
#define  copystruct(d,s)        memcpy((void *)(d),(void *)(s),sizeof(*(d)))
#else
#define  copystruct(d,s)        (*(d) = *(s))
#endif


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)
                                copystruct(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:	2.9
Committed:	Mon Jun 30 14:59:11 2003 UTC (20 years, 10 months ago) by schorsch
Content type:	text/plain
Branch:	MAIN
Changes since 2.8:	+4 -2 lines
Log Message:	Replaced most outdated BSD function calls with their posix equivalents, and cleaned up a few other platform dependencies.
#	Content
1	#ifndef lint
2	static const char RCSid[] = "$Id: lookup.c,v 2.8 2003/05/13 17:58:32 greg Exp $";
3	#endif
4	/*
5	* Table lookup routines
6	*/
7
8	#include "copyright.h"
9
10	#include <stdio.h>
11	#include <stdlib.h>
12	#include <string.h>
13
14	#include "lookup.h"
15
16	#ifdef NOSTRUCTASS
17	#define copystruct(d,s) memcpy((void )(d),(void )(s),sizeof(*(d)))
18	#else
19	#define copystruct(d,s) ((d) = (s))
20	#endif
21
22
23	int
24	lu_init(tbl, nel) /* initialize tbl for at least nel elements */
25	register LUTAB *tbl;
26	int nel;
27	{
28	static int hsiztab[] = {
29	31, 61, 127, 251, 509, 1021, 2039, 4093, 8191, 16381,
30	32749, 65521, 131071, 262139, 524287, 1048573, 2097143,
31	4194301, 8388593, 0
32	};
33	register int *hsp;
34
35	nel += nel>>1; /* 66% occupancy */
36	for (hsp = hsiztab; *hsp; hsp++)
37	if (*hsp > nel)
38	break;
39	if (!(tbl->tsiz = *hsp))
40	tbl->tsiz = nel2 + 1; / not always prime */
41	tbl->tabl = (LUENT *)calloc(tbl->tsiz, sizeof(LUENT));
42	if (tbl->tabl == NULL)
43	tbl->tsiz = 0;
44	tbl->ndel = 0;
45	return(tbl->tsiz);
46	}
47
48
49	unsigned long
50	lu_shash(s) /* hash a nul-terminated string */
51	char *s;
52	{
53	static unsigned char shuffle[256] = {
54	0, 157, 58, 215, 116, 17, 174, 75, 232, 133, 34,
55	191, 92, 249, 150, 51, 208, 109, 10, 167, 68, 225,
56	126, 27, 184, 85, 242, 143, 44, 201, 102, 3, 160,
57	61, 218, 119, 20, 177, 78, 235, 136, 37, 194, 95,
58	252, 153, 54, 211, 112, 13, 170, 71, 228, 129, 30,
59	187, 88, 245, 146, 47, 204, 105, 6, 163, 64, 221,
60	122, 23, 180, 81, 238, 139, 40, 197, 98, 255, 156,
61	57, 214, 115, 16, 173, 74, 231, 132, 33, 190, 91,
62	248, 149, 50, 207, 108, 9, 166, 67, 224, 125, 26,
63	183, 84, 241, 142, 43, 200, 101, 2, 159, 60, 217,
64	118, 19, 176, 77, 234, 135, 36, 193, 94, 251, 152,
65	53, 210, 111, 12, 169, 70, 227, 128, 29, 186, 87,
66	244, 145, 46, 203, 104, 5, 162, 63, 220, 121, 22,
67	179, 80, 237, 138, 39, 196, 97, 254, 155, 56, 213,
68	114, 15, 172, 73, 230, 131, 32, 189, 90, 247, 148,
69	49, 206, 107, 8, 165, 66, 223, 124, 25, 182, 83,
70	240, 141, 42, 199, 100, 1, 158, 59, 216, 117, 18,
71	175, 76, 233, 134, 35, 192, 93, 250, 151, 52, 209,
72	110, 11, 168, 69, 226, 127, 28, 185, 86, 243, 144,
73	45, 202, 103, 4, 161, 62, 219, 120, 21, 178, 79,
74	236, 137, 38, 195, 96, 253, 154, 55, 212, 113, 14,
75	171, 72, 229, 130, 31, 188, 89, 246, 147, 48, 205,
76	106, 7, 164, 65, 222, 123, 24, 181, 82, 239, 140,
77	41, 198, 99
78	};
79	register int i = 0;
80	register unsigned long h = 0;
81	register unsigned char t = (unsigned char )s;
82
83	while (*t)
84	h ^= (unsigned long)shuffle[*t++] << ((i+=11) & 0xf);
85
86	return(h);
87	}
88
89
90	LUENT *
91	lu_find(tbl, key) /* find a table entry */
92	register LUTAB *tbl;
93	char *key;
94	{
95	unsigned long hval;
96	int i, n;
97	register int ndx;
98	register LUENT *le;
99	/* look up object */
100	if (tbl->tsiz == 0 && !lu_init(tbl, 1))
101	return(NULL);
102	hval = (*tbl->hashf)(key);
103	tryagain:
104	ndx = hval % tbl->tsiz;
105	for (i = 0, n = 1; i < tbl->tsiz; i++, n += 2) {
106	le = &tbl->tabl[ndx];
107	if (le->key == NULL) {
108	le->hval = hval;
109	return(le);
110	}
111	if (le->hval == hval &&
112	(tbl->keycmp == NULL \|\| !(*tbl->keycmp)(le->key, key))) {
113	return(le);
114	}
115	if ((ndx += n) >= tbl->tsiz) /* this happens rarely */
116	ndx = ndx % tbl->tsiz;
117	}
118	/* table is full, reallocate */
119	le = tbl->tabl;
120	ndx = tbl->tsiz;
121	i = tbl->ndel;
122	if (!lu_init(tbl, ndx-i+1)) { /* no more memory! */
123	tbl->tabl = le;
124	tbl->tsiz = ndx;
125	tbl->ndel = i;
126	return(NULL);
127	}
128	/*
129	* The following code may fail if the user has reclaimed many
130	* deleted entries and the system runs out of memory in a
131	* recursive call to lu_find().
132	*/
133	while (ndx--)
134	if (le[ndx].key != NULL)
135	if (le[ndx].data != NULL)
136	copystruct(lu_find(tbl,le[ndx].key), &le[ndx]);
137	else if (tbl->freek != NULL)
138	(*tbl->freek)(le[ndx].key);
139	free((void *)le);
140	goto tryagain; /* should happen only once! */
141	}
142
143
144	void
145	lu_delete(tbl, key) /* delete a table entry */
146	register LUTAB *tbl;
147	char *key;
148	{
149	register LUENT *le;
150
151	if ((le = lu_find(tbl, key)) == NULL)
152	return;
153	if (le->key == NULL \|\| le->data == NULL)
154	return;
155	if (tbl->freed != NULL)
156	(*tbl->freed)(le->data);
157	le->data = NULL;
158	tbl->ndel++;
159	}
160
161
162	int
163	lu_doall(tbl, f) /* loop through all valid table entries */
164	register LUTAB *tbl;
165	int (*f)();
166	{
167	int rval = 0;
168	register LUENT *tp;
169
170	for (tp = tbl->tabl + tbl->tsiz; tp-- > tbl->tabl; )
171	if (tp->data != NULL)
172	if (f != NULL)
173	rval += (*f)(tp);
174	else
175	rval++;
176	return(rval);
177	}
178
179
180	void
181	lu_done(tbl) /* free table and contents */
182	register LUTAB *tbl;
183	{
184	register LUENT *tp;
185
186	if (!tbl->tsiz)
187	return;
188	for (tp = tbl->tabl + tbl->tsiz; tp-- > tbl->tabl; )
189	if (tp->key != NULL) {
190	if (tbl->freek != NULL)
191	(*tbl->freek)(tp->key);
192	if (tp->data != NULL && tbl->freed != NULL)
193	(*tbl->freed)(tp->data);
194	}
195	free((void *)tbl->tabl);
196	tbl->tabl = NULL;
197	tbl->tsiz = 0;
198	tbl->ndel = 0;
199	}