src/common/lookup.c

#ifndef lint
static const char       RCSid[] = "$Id: lookup.c,v 2.16 2006/06/07 17:52:03 schorsch Exp $";
#endif
/*
 * Table lookup routines
 */

#include <stdio.h>
#include <stdlib.h>
#include <string.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:	2.17
Committed:	Sat May 1 21:49:42 2010 UTC (15 years, 6 months ago) by greg
Content type:	text/plain
Branch:	MAIN
Changes since 2.16:	+2 -2 lines
Log Message:	Removed C++ comments
#	User	Rev	Content
1	greg	2.1	#ifndef lint
2	greg	2.17	static const char RCSid[] = "$Id: lookup.c,v 2.16 2006/06/07 17:52:03 schorsch 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	2.16	#include <string.h>
11	schorsch	2.9
12	greg	2.1	#include "lookup.h"
13
14	schorsch	2.13	extern int
15			lu_strcmp(
16			const void *s1,
17			const void *s2
18			)
19			{
20			return strcmp((const char)s1,(const char)s2);
21			}
22	greg	2.1
23	schorsch	2.13	extern int
24			lu_init( /* initialize tbl for at least nel elements */
25			register LUTAB *tbl,
26			int nel
27			)
28	greg	2.1	{
29			static int hsiztab[] = {
30	gregl	2.3	31, 61, 127, 251, 509, 1021, 2039, 4093, 8191, 16381,
31			32749, 65521, 131071, 262139, 524287, 1048573, 2097143,
32			4194301, 8388593, 0
33	greg	2.1	};
34			register int *hsp;
35
36			nel += nel>>1; /* 66% occupancy */
37			for (hsp = hsiztab; *hsp; hsp++)
38			if (*hsp > nel)
39			break;
40			if (!(tbl->tsiz = *hsp))
41			tbl->tsiz = nel2 + 1; / not always prime */
42			tbl->tabl = (LUENT *)calloc(tbl->tsiz, sizeof(LUENT));
43			if (tbl->tabl == NULL)
44			tbl->tsiz = 0;
45			tbl->ndel = 0;
46			return(tbl->tsiz);
47			}
48
49
50	schorsch	2.13	extern unsigned long
51			lu_shash( /* hash a nul-terminated string */
52	greg	2.15	const void *s
53	schorsch	2.13	)
54	greg	2.1	{
55	gregl	2.3	static unsigned char shuffle[256] = {
56			0, 157, 58, 215, 116, 17, 174, 75, 232, 133, 34,
57			191, 92, 249, 150, 51, 208, 109, 10, 167, 68, 225,
58			126, 27, 184, 85, 242, 143, 44, 201, 102, 3, 160,
59			61, 218, 119, 20, 177, 78, 235, 136, 37, 194, 95,
60			252, 153, 54, 211, 112, 13, 170, 71, 228, 129, 30,
61			187, 88, 245, 146, 47, 204, 105, 6, 163, 64, 221,
62			122, 23, 180, 81, 238, 139, 40, 197, 98, 255, 156,
63			57, 214, 115, 16, 173, 74, 231, 132, 33, 190, 91,
64			248, 149, 50, 207, 108, 9, 166, 67, 224, 125, 26,
65			183, 84, 241, 142, 43, 200, 101, 2, 159, 60, 217,
66			118, 19, 176, 77, 234, 135, 36, 193, 94, 251, 152,
67			53, 210, 111, 12, 169, 70, 227, 128, 29, 186, 87,
68			244, 145, 46, 203, 104, 5, 162, 63, 220, 121, 22,
69			179, 80, 237, 138, 39, 196, 97, 254, 155, 56, 213,
70			114, 15, 172, 73, 230, 131, 32, 189, 90, 247, 148,
71			49, 206, 107, 8, 165, 66, 223, 124, 25, 182, 83,
72			240, 141, 42, 199, 100, 1, 158, 59, 216, 117, 18,
73			175, 76, 233, 134, 35, 192, 93, 250, 151, 52, 209,
74			110, 11, 168, 69, 226, 127, 28, 185, 86, 243, 144,
75			45, 202, 103, 4, 161, 62, 219, 120, 21, 178, 79,
76			236, 137, 38, 195, 96, 253, 154, 55, 212, 113, 14,
77			171, 72, 229, 130, 31, 188, 89, 246, 147, 48, 205,
78			106, 7, 164, 65, 222, 123, 24, 181, 82, 239, 140,
79			41, 198, 99
80			};
81	greg	2.1	register int i = 0;
82	gwlarson	2.5	register unsigned long h = 0;
83	greg	2.15	register unsigned const char t = (unsigned const char )s;
84	greg	2.1
85	gregl	2.3	while (*t)
86	gwlarson	2.5	h ^= (unsigned long)shuffle[*t++] << ((i+=11) & 0xf);
87	gregl	2.3
88	greg	2.1	return(h);
89			}
90
91
92	schorsch	2.13	extern LUENT *
93			lu_find( /* find a table entry */
94			register LUTAB *tbl,
95	greg	2.15	const char *key
96	schorsch	2.13	)
97	greg	2.1	{
98	gwlarson	2.5	unsigned long hval;
99	gregl	2.3	int i, n;
100	greg	2.1	register int ndx;
101	gregl	2.3	register LUENT *le;
102	greg	2.1	/* look up object */
103	gwlarson	2.5	if (tbl->tsiz == 0 && !lu_init(tbl, 1))
104			return(NULL);
105	greg	2.1	hval = (*tbl->hashf)(key);
106			tryagain:
107	gregl	2.3	ndx = hval % tbl->tsiz;
108			for (i = 0, n = 1; i < tbl->tsiz; i++, n += 2) {
109	gwlarson	2.5	le = &tbl->tabl[ndx];
110	gregl	2.3	if (le->key == NULL) {
111			le->hval = hval;
112			return(le);
113	greg	2.1	}
114	gregl	2.3	if (le->hval == hval &&
115			(tbl->keycmp == NULL \|\| !(*tbl->keycmp)(le->key, key))) {
116			return(le);
117			}
118	gwlarson	2.5	if ((ndx += n) >= tbl->tsiz) /* this happens rarely */
119	gregl	2.3	ndx = ndx % tbl->tsiz;
120	greg	2.1	}
121			/* table is full, reallocate */
122	gregl	2.3	le = tbl->tabl;
123	greg	2.1	ndx = tbl->tsiz;
124			i = tbl->ndel;
125	greg	2.2	if (!lu_init(tbl, ndx-i+1)) { /* no more memory! */
126	gregl	2.3	tbl->tabl = le;
127	greg	2.1	tbl->tsiz = ndx;
128			tbl->ndel = i;
129			return(NULL);
130			}
131			/*
132			* The following code may fail if the user has reclaimed many
133			* deleted entries and the system runs out of memory in a
134			* recursive call to lu_find().
135			*/
136			while (ndx--)
137	schorsch	2.10	if (le[ndx].key != NULL) {
138	gregl	2.3	if (le[ndx].data != NULL)
139	schorsch	2.10	*lu_find(tbl,le[ndx].key) = le[ndx];
140	greg	2.1	else if (tbl->freek != NULL)
141	gregl	2.3	(*tbl->freek)(le[ndx].key);
142	schorsch	2.10	}
143	greg	2.6	free((void *)le);
144	greg	2.1	goto tryagain; /* should happen only once! */
145			}
146
147
148	schorsch	2.13	extern void
149			lu_delete( /* delete a table entry */
150			register LUTAB *tbl,
151	greg	2.15	const char *key
152	schorsch	2.13	)
153	greg	2.1	{
154			register LUENT *le;
155
156			if ((le = lu_find(tbl, key)) == NULL)
157			return;
158			if (le->key == NULL \|\| le->data == NULL)
159			return;
160			if (tbl->freed != NULL)
161			(*tbl->freed)(le->data);
162			le->data = NULL;
163			tbl->ndel++;
164			}
165
166
167	schorsch	2.13	extern int
168			lu_doall( /* loop through all valid table entries */
169	greg	2.15	register const LUTAB *tbl,
170	greg	2.17	/* int (f)(const LUENT ) */
171	greg	2.14	lut_doallf_t *f,
172			void *p
173	schorsch	2.13	)
174	gwlarson	2.4	{
175			int rval = 0;
176	greg	2.15	register const LUENT *tp;
177	gwlarson	2.4
178			for (tp = tbl->tabl + tbl->tsiz; tp-- > tbl->tabl; )
179	schorsch	2.10	if (tp->data != NULL) {
180	greg	2.14	if (f != NULL) {
181			int r = (*f)(tp, p);
182			if (r < 0)
183			return(-1);
184			rval += r;
185			} else
186	gwlarson	2.4	rval++;
187	schorsch	2.10	}
188	gwlarson	2.4	return(rval);
189			}
190
191
192	schorsch	2.13	extern void
193			lu_done( /* free table and contents */
194			register LUTAB *tbl
195			)
196	greg	2.1	{
197			register LUENT *tp;
198
199			if (!tbl->tsiz)
200			return;
201			for (tp = tbl->tabl + tbl->tsiz; tp-- > tbl->tabl; )
202			if (tp->key != NULL) {
203			if (tbl->freek != NULL)
204			(*tbl->freek)(tp->key);
205			if (tp->data != NULL && tbl->freed != NULL)
206			(*tbl->freed)(tp->data);
207			}
208	greg	2.6	free((void *)tbl->tabl);
209	greg	2.1	tbl->tabl = NULL;
210			tbl->tsiz = 0;
211			tbl->ndel = 0;
212			}