| 1 |
/* Copyright (c) 1994 Regents of the University of California */ |
| 2 |
|
| 3 |
#ifndef lint |
| 4 |
static char SCCSid[] = "$SunId$ LBL"; |
| 5 |
#endif |
| 6 |
|
| 7 |
/* |
| 8 |
* Table lookup routines |
| 9 |
*/ |
| 10 |
|
| 11 |
#include <stdio.h> |
| 12 |
#include "lookup.h" |
| 13 |
|
| 14 |
#ifndef MEM_PTR |
| 15 |
#define MEM_PTR void * |
| 16 |
#endif |
| 17 |
|
| 18 |
extern MEM_PTR calloc(); |
| 19 |
|
| 20 |
|
| 21 |
int |
| 22 |
lu_init(tbl, nel) /* initialize tbl for at least nel elements */ |
| 23 |
register LUTAB *tbl; |
| 24 |
int nel; |
| 25 |
{ |
| 26 |
static int hsiztab[] = { |
| 27 |
31, 61, 127, 251, 509, 1021, 2039, 4093, 8191, 16381, 0 |
| 28 |
}; |
| 29 |
register int *hsp; |
| 30 |
|
| 31 |
nel += nel>>1; /* 66% occupancy */ |
| 32 |
for (hsp = hsiztab; *hsp; hsp++) |
| 33 |
if (*hsp > nel) |
| 34 |
break; |
| 35 |
if (!(tbl->tsiz = *hsp)) |
| 36 |
tbl->tsiz = nel*2 + 1; /* not always prime */ |
| 37 |
tbl->tabl = (LUENT *)calloc(tbl->tsiz, sizeof(LUENT)); |
| 38 |
if (tbl->tabl == NULL) |
| 39 |
tbl->tsiz = 0; |
| 40 |
tbl->ndel = 0; |
| 41 |
return(tbl->tsiz); |
| 42 |
} |
| 43 |
|
| 44 |
|
| 45 |
int |
| 46 |
lu_hash(s) /* hash a nul-terminated string */ |
| 47 |
register char *s; |
| 48 |
{ |
| 49 |
register int h = 0; |
| 50 |
|
| 51 |
while (*s) |
| 52 |
h = (h<<1 & 0x7fff) ^ (*s++ & 0xff); |
| 53 |
return(h); |
| 54 |
} |
| 55 |
|
| 56 |
|
| 57 |
LUENT * |
| 58 |
lu_find(tbl, key) /* find a table entry */ |
| 59 |
register LUTAB *tbl; |
| 60 |
char *key; |
| 61 |
{ |
| 62 |
int hval, i; |
| 63 |
register int ndx; |
| 64 |
LUENT *oldtabl; |
| 65 |
/* look up object */ |
| 66 |
hval = lu_hash(key); |
| 67 |
tryagain: |
| 68 |
for (i = 0; i < tbl->tsiz; i++) { |
| 69 |
ndx = (hval + i*i) % tbl->tsiz; |
| 70 |
if (tbl->tabl[ndx].key == NULL || |
| 71 |
!strcmp(tbl->tabl[ndx].key, key)) |
| 72 |
return(&tbl->tabl[ndx]); |
| 73 |
} |
| 74 |
/* table is full, reallocate */ |
| 75 |
oldtabl = tbl->tabl; |
| 76 |
ndx = tbl->tsiz; |
| 77 |
i = tbl->ndel; |
| 78 |
if (!lu_init(tbl, ndx-i)) { /* no more memory! */ |
| 79 |
tbl->tabl = oldtabl; |
| 80 |
tbl->tsiz = ndx; |
| 81 |
tbl->ndel = i; |
| 82 |
return(NULL); |
| 83 |
} |
| 84 |
if (!ndx) |
| 85 |
goto tryagain; |
| 86 |
while (ndx--) |
| 87 |
if (oldtabl[ndx].key != NULL) |
| 88 |
if (oldtabl[ndx].data != NULL) |
| 89 |
*lu_find(tbl, oldtabl[ndx].key) = oldtabl[ndx]; |
| 90 |
else if (tbl->freek != NULL) |
| 91 |
(*tbl->freek)(oldtabl[ndx].key); |
| 92 |
free((MEM_PTR)oldtabl); |
| 93 |
goto tryagain; /* should happen only once! */ |
| 94 |
} |
| 95 |
|
| 96 |
|
| 97 |
void |
| 98 |
lu_delete(tbl, key) /* delete a table entry */ |
| 99 |
register LUTAB *tbl; |
| 100 |
char *key; |
| 101 |
{ |
| 102 |
register LUENT *le; |
| 103 |
|
| 104 |
if ((le = lu_find(tbl, key)) == NULL) |
| 105 |
return; |
| 106 |
if (le->key == NULL || le->data == NULL) |
| 107 |
return; |
| 108 |
if (tbl->freed != NULL) |
| 109 |
(*tbl->freed)(le->data); |
| 110 |
le->data = NULL; |
| 111 |
tbl->ndel++; |
| 112 |
} |
| 113 |
|
| 114 |
|
| 115 |
void |
| 116 |
lu_done(tbl) /* free table and contents */ |
| 117 |
register LUTAB *tbl; |
| 118 |
{ |
| 119 |
register LUENT *tp; |
| 120 |
|
| 121 |
if (!tbl->tsiz) |
| 122 |
return; |
| 123 |
for (tp = tbl->tabl + tbl->tsiz; tp-- > tbl->tabl; ) |
| 124 |
if (tp->key != NULL) { |
| 125 |
if (tbl->freek != NULL) |
| 126 |
(*tbl->freek)(tp->key); |
| 127 |
if (tp->data != NULL && tbl->freed != NULL) |
| 128 |
(*tbl->freed)(tp->data); |
| 129 |
} |
| 130 |
free((MEM_PTR)tbl->tabl); |
| 131 |
tbl->tabl = NULL; |
| 132 |
tbl->tsiz = 0; |
| 133 |
tbl->ndel = 0; |
| 134 |
} |
