--- ray/src/cv/mgflib/lookup.c 1994/06/21 14:45:45 1.1 +++ ray/src/cv/mgflib/lookup.c 2003/02/28 20:11:29 1.8 @@ -1,34 +1,32 @@ -/* Copyright (c) 1994 Regents of the University of California */ - #ifndef lint -static char SCCSid[] = "$SunId$ LBL"; +static const char RCSid[] = "$Id: lookup.c,v 1.8 2003/02/28 20:11:29 greg Exp $"; #endif - /* * Table lookup routines */ #include +#include #include "lookup.h" #ifndef MEM_PTR #define MEM_PTR void * #endif -extern MEM_PTR calloc(); - 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, 0 + 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>>2; /* 75% occupancy */ + nel += nel>>1; /* 66% occupancy */ for (hsp = hsiztab; *hsp; hsp++) if (*hsp > nel) break; @@ -37,18 +35,48 @@ int nel; tbl->tabl = (LUENT *)calloc(tbl->tsiz, sizeof(LUENT)); if (tbl->tabl == NULL) tbl->tsiz = 0; + tbl->ndel = 0; return(tbl->tsiz); } -int -lu_hash(s) /* hash a nul-terminated string */ -register char *s; +unsigned long +lu_shash(s) /* hash a nul-terminated string */ +char *s; { - register int h = 0; + 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 (*s) - h = (h<<1 & 0x7fff) ^ (*s++ & 0xff); + while (*t) + h ^= (long)shuffle[*t++] << ((i+=11) & 0xf); + return(h); } @@ -58,54 +86,90 @@ lu_find(tbl, key) /* find a table entry */ register LUTAB *tbl; char *key; { - int hval, i; - register int ndx; + unsigned long hval; + int i, n; + register int ndx; register LUENT *le; - LUENT *oldtabl; /* look up object */ - hval = lu_hash(key); + if (tbl->tsiz == 0 && !lu_init(tbl, 1)) + return(NULL); + hval = (*tbl->hashf)(key); tryagain: - for (i = 0; i < tbl->tsiz; i++) { - ndx = (hval + i*i) % tbl->tsiz; - if (tbl->tabl[ndx].key == NULL || - !strcmp(tbl->tabl[ndx].key, key)) - return(&tbl->tabl[ndx]); + 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 */ - oldtabl = tbl->tabl; + le = tbl->tabl; ndx = tbl->tsiz; - if (!lu_init(tbl, ndx)) { /* no more memory! */ - tbl->tabl = oldtabl; + i = tbl->ndel; + if (!lu_init(tbl, ndx-i+1)) { /* no more memory! */ + tbl->tabl = le; tbl->tsiz = ndx; + tbl->ndel = i; return(NULL); } - if (!ndx) - goto tryagain; + /* + * 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 (oldtabl[ndx].key != NULL) { - le = lu_find(tbl, oldtabl[ndx].key); - le->key = oldtabl[ndx].key; - le->data = oldtabl[ndx].data; - } - free((MEM_PTR)oldtabl); + 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((MEM_PTR)le); goto tryagain; /* should happen only once! */ } void -lu_done(tbl, f) /* free table and contents */ -LUTAB *tbl; -int (*f)(); +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++; +} + + +void +lu_done(tbl) /* free table and contents */ +register LUTAB *tbl; +{ register LUENT *tp; if (!tbl->tsiz) return; - if (f != NULL) - for (tp = tbl->tabl + tbl->tsiz; tp-- > tbl->tabl; ) - if (tp->key != NULL) - (*f)(tp); + 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((MEM_PTR)tbl->tabl); tbl->tabl = NULL; tbl->tsiz = 0; + tbl->ndel = 0; }