src/common/lookup.c

#ifndef lint
static const char       RCSid[] = "$Id: lookup.c,v 2.14 2004/05/25 06:30:46 greg Exp $";
#endif
/*
 * Table lookup routines
 */

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

#include "lookup.h"

extern int
lu_strcmp(
        const void *s1,
        const void *s2
)
{
        return strcmp((const char*)s1,(const char*)s2);
}

extern int
lu_init(                /* 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);
}


extern unsigned long
lu_shash(                       /* hash a nul-terminated string */
        const void      *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 const char *t = (unsigned const char *)s;

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

        return(h);
}


extern LUENT *
lu_find(                /* find a table entry */
        register LUTAB  *tbl,
        const 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! */
}


extern void
lu_delete(              /* delete a table entry */
        register LUTAB  *tbl,
        const 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++;
}


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

        for (tp = tbl->tabl + tbl->tsiz; tp-- > tbl->tabl; )
                if (tp->data != NULL) {
                        if (f != NULL) {
                                int     r = (*f)(tp, p);
                                if (r < 0)
                                        return(-1);
                                rval += r;
                        } else
                                rval++;
                }
        return(rval);
}


extern void
lu_done(                        /* 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:	2.15
Committed:	Tue May 25 22:04:13 2004 UTC (19 years, 11 months ago) by greg
Content type:	text/plain
Branch:	MAIN
CVS Tags:	rad3R7P2, rad3R7P1, rad3R6, rad3R6P1
Changes since 2.14:	+8 -8 lines
Log Message:	Added const modifier to key and other parameters in lookup.h
#	User	Rev	Content
1	greg	2.1	#ifndef lint
2	greg	2.15	static const char RCSid[] = "$Id: lookup.c,v 2.14 2004/05/25 06:30:46 greg Exp $";
3	greg	2.1	#endif
4			/*
5			* Table lookup routines
6			*/
7	greg	2.6
8	greg	2.1	#include <stdio.h>
9	greg	2.6	#include <stdlib.h>
10	schorsch	2.9
11	greg	2.1	#include "lookup.h"
12
13	schorsch	2.13	extern int
14			lu_strcmp(
15			const void *s1,
16			const void *s2
17			)
18			{
19			return strcmp((const char)s1,(const char)s2);
20			}
21	greg	2.1
22	schorsch	2.13	extern int
23			lu_init( /* initialize tbl for at least nel elements */
24			register LUTAB *tbl,
25			int nel
26			)
27	greg	2.1	{
28			static int hsiztab[] = {
29	gregl	2.3	31, 61, 127, 251, 509, 1021, 2039, 4093, 8191, 16381,
30			32749, 65521, 131071, 262139, 524287, 1048573, 2097143,
31			4194301, 8388593, 0
32	greg	2.1	};
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	schorsch	2.13	extern unsigned long
50			lu_shash( /* hash a nul-terminated string */
51	greg	2.15	const void *s
52	schorsch	2.13	)
53	greg	2.1	{
54	gregl	2.3	static unsigned char shuffle[256] = {
55			0, 157, 58, 215, 116, 17, 174, 75, 232, 133, 34,
56			191, 92, 249, 150, 51, 208, 109, 10, 167, 68, 225,
57			126, 27, 184, 85, 242, 143, 44, 201, 102, 3, 160,
58			61, 218, 119, 20, 177, 78, 235, 136, 37, 194, 95,
59			252, 153, 54, 211, 112, 13, 170, 71, 228, 129, 30,
60			187, 88, 245, 146, 47, 204, 105, 6, 163, 64, 221,
61			122, 23, 180, 81, 238, 139, 40, 197, 98, 255, 156,
62			57, 214, 115, 16, 173, 74, 231, 132, 33, 190, 91,
63			248, 149, 50, 207, 108, 9, 166, 67, 224, 125, 26,
64			183, 84, 241, 142, 43, 200, 101, 2, 159, 60, 217,
65			118, 19, 176, 77, 234, 135, 36, 193, 94, 251, 152,
66			53, 210, 111, 12, 169, 70, 227, 128, 29, 186, 87,
67			244, 145, 46, 203, 104, 5, 162, 63, 220, 121, 22,
68			179, 80, 237, 138, 39, 196, 97, 254, 155, 56, 213,
69			114, 15, 172, 73, 230, 131, 32, 189, 90, 247, 148,
70			49, 206, 107, 8, 165, 66, 223, 124, 25, 182, 83,
71			240, 141, 42, 199, 100, 1, 158, 59, 216, 117, 18,
72			175, 76, 233, 134, 35, 192, 93, 250, 151, 52, 209,
73			110, 11, 168, 69, 226, 127, 28, 185, 86, 243, 144,
74			45, 202, 103, 4, 161, 62, 219, 120, 21, 178, 79,
75			236, 137, 38, 195, 96, 253, 154, 55, 212, 113, 14,
76			171, 72, 229, 130, 31, 188, 89, 246, 147, 48, 205,
77			106, 7, 164, 65, 222, 123, 24, 181, 82, 239, 140,
78			41, 198, 99
79			};
80	greg	2.1	register int i = 0;
81	gwlarson	2.5	register unsigned long h = 0;
82	greg	2.15	register unsigned const char t = (unsigned const char )s;
83	greg	2.1
84	gregl	2.3	while (*t)
85	gwlarson	2.5	h ^= (unsigned long)shuffle[*t++] << ((i+=11) & 0xf);
86	gregl	2.3
87	greg	2.1	return(h);
88			}
89
90
91	schorsch	2.13	extern LUENT *
92			lu_find( /* find a table entry */
93			register LUTAB *tbl,
94	greg	2.15	const char *key
95	schorsch	2.13	)
96	greg	2.1	{
97	gwlarson	2.5	unsigned long hval;
98	gregl	2.3	int i, n;
99	greg	2.1	register int ndx;
100	gregl	2.3	register LUENT *le;
101	greg	2.1	/* look up object */
102	gwlarson	2.5	if (tbl->tsiz == 0 && !lu_init(tbl, 1))
103			return(NULL);
104	greg	2.1	hval = (*tbl->hashf)(key);
105			tryagain:
106	gregl	2.3	ndx = hval % tbl->tsiz;
107			for (i = 0, n = 1; i < tbl->tsiz; i++, n += 2) {
108	gwlarson	2.5	le = &tbl->tabl[ndx];
109	gregl	2.3	if (le->key == NULL) {
110			le->hval = hval;
111			return(le);
112	greg	2.1	}
113	gregl	2.3	if (le->hval == hval &&
114			(tbl->keycmp == NULL \|\| !(*tbl->keycmp)(le->key, key))) {
115			return(le);
116			}
117	gwlarson	2.5	if ((ndx += n) >= tbl->tsiz) /* this happens rarely */
118	gregl	2.3	ndx = ndx % tbl->tsiz;
119	greg	2.1	}
120			/* table is full, reallocate */
121	gregl	2.3	le = tbl->tabl;
122	greg	2.1	ndx = tbl->tsiz;
123			i = tbl->ndel;
124	greg	2.2	if (!lu_init(tbl, ndx-i+1)) { /* no more memory! */
125	gregl	2.3	tbl->tabl = le;
126	greg	2.1	tbl->tsiz = ndx;
127			tbl->ndel = i;
128			return(NULL);
129			}
130			/*
131			* The following code may fail if the user has reclaimed many
132			* deleted entries and the system runs out of memory in a
133			* recursive call to lu_find().
134			*/
135			while (ndx--)
136	schorsch	2.10	if (le[ndx].key != NULL) {
137	gregl	2.3	if (le[ndx].data != NULL)
138	schorsch	2.10	*lu_find(tbl,le[ndx].key) = le[ndx];
139	greg	2.1	else if (tbl->freek != NULL)
140	gregl	2.3	(*tbl->freek)(le[ndx].key);
141	schorsch	2.10	}
142	greg	2.6	free((void *)le);
143	greg	2.1	goto tryagain; /* should happen only once! */
144			}
145
146
147	schorsch	2.13	extern void
148			lu_delete( /* delete a table entry */
149			register LUTAB *tbl,
150	greg	2.15	const char *key
151	schorsch	2.13	)
152	greg	2.1	{
153			register LUENT *le;
154
155			if ((le = lu_find(tbl, key)) == NULL)
156			return;
157			if (le->key == NULL \|\| le->data == NULL)
158			return;
159			if (tbl->freed != NULL)
160			(*tbl->freed)(le->data);
161			le->data = NULL;
162			tbl->ndel++;
163			}
164
165
166	schorsch	2.13	extern int
167			lu_doall( /* loop through all valid table entries */
168	greg	2.15	register const LUTAB *tbl,
169			//int (f)(const LUENT )
170	greg	2.14	lut_doallf_t *f,
171			void *p
172	schorsch	2.13	)
173	gwlarson	2.4	{
174			int rval = 0;
175	greg	2.15	register const LUENT *tp;
176	gwlarson	2.4
177			for (tp = tbl->tabl + tbl->tsiz; tp-- > tbl->tabl; )
178	schorsch	2.10	if (tp->data != NULL) {
179	greg	2.14	if (f != NULL) {
180			int r = (*f)(tp, p);
181			if (r < 0)
182			return(-1);
183			rval += r;
184			} else
185	gwlarson	2.4	rval++;
186	schorsch	2.10	}
187	gwlarson	2.4	return(rval);
188			}
189
190
191	schorsch	2.13	extern void
192			lu_done( /* free table and contents */
193			register LUTAB *tbl
194			)
195	greg	2.1	{
196			register LUENT *tp;
197
198			if (!tbl->tsiz)
199			return;
200			for (tp = tbl->tabl + tbl->tsiz; tp-- > tbl->tabl; )
201			if (tp->key != NULL) {
202			if (tbl->freek != NULL)
203			(*tbl->freek)(tp->key);
204			if (tp->data != NULL && tbl->freed != NULL)
205			(*tbl->freed)(tp->data);
206			}
207	greg	2.6	free((void *)tbl->tabl);
208	greg	2.1	tbl->tabl = NULL;
209			tbl->tsiz = 0;
210			tbl->ndel = 0;
211			}