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/* hash.c
*
* Copyright (C) 1991, 1992, 1993, 1994, 1995, 1999, 2000, 2001, 2002,
* 2005 by Larry Wall and others
*
* You may distribute under the terms of either the GNU General Public
* License or the Artistic License, as specified in the README file.
*/
#include <stdio.h>
#include "EXTERN.h"
#include "a2p.h"
#include "util.h"
#ifdef NETWARE
char *savestr(char *str);
#endif
STR *
hfetch(register HASH *tb, char *key)
{
register char *s;
register int i;
register int hash;
register HENT *entry;
if (!tb)
return NULL;
for (s=key, i=0, hash = 0;
/* while */ *s;
s++, i++, hash *= 5) {
hash += *s * coeff[i];
}
entry = tb->tbl_array[hash & tb->tbl_max];
for (; entry; entry = entry->hent_next) {
if (entry->hent_hash != hash) /* strings can't be equal */
continue;
if (strNE(entry->hent_key,key)) /* is this it? */
continue;
return entry->hent_val;
}
return NULL;
}
bool
hstore(register HASH *tb, char *key, STR *val)
{
register char *s;
register int i;
register int hash;
register HENT *entry;
register HENT **oentry;
if (!tb)
return FALSE;
for (s=key, i=0, hash = 0;
/* while */ *s;
s++, i++, hash *= 5) {
hash += *s * coeff[i];
}
oentry = &(tb->tbl_array[hash & tb->tbl_max]);
i = 1;
for (entry = *oentry; entry; i=0, entry = entry->hent_next) {
if (entry->hent_hash != hash) /* strings can't be equal */
continue;
if (strNE(entry->hent_key,key)) /* is this it? */
continue;
/*NOSTRICT*/
safefree(entry->hent_val);
entry->hent_val = val;
return TRUE;
}
/*NOSTRICT*/
entry = (HENT*) safemalloc(sizeof(HENT));
entry->hent_key = savestr(key);
entry->hent_val = val;
entry->hent_hash = hash;
entry->hent_next = *oentry;
*oentry = entry;
if (i) { /* initial entry? */
tb->tbl_fill++;
if ((tb->tbl_fill * 100 / (tb->tbl_max + 1)) > FILLPCT)
hsplit(tb);
}
return FALSE;
}
void
hsplit(HASH *tb)
{
const int oldsize = tb->tbl_max + 1;
register int newsize = oldsize * 2;
register int i;
register HENT **a;
register HENT **b;
register HENT *entry;
register HENT **oentry;
a = (HENT**) saferealloc((char*)tb->tbl_array, newsize * sizeof(HENT*));
memset(&a[oldsize], 0, oldsize * sizeof(HENT*)); /* zero second half */
tb->tbl_max = --newsize;
tb->tbl_array = a;
for (i=0; i<oldsize; i++,a++) {
if (!*a) /* non-existent */
continue;
b = a+oldsize;
for (oentry = a, entry = *a; entry; entry = *oentry) {
if ((entry->hent_hash & newsize) != i) {
*oentry = entry->hent_next;
entry->hent_next = *b;
if (!*b)
tb->tbl_fill++;
*b = entry;
continue;
}
else
oentry = &entry->hent_next;
}
if (!*a) /* everything moved */
tb->tbl_fill--;
}
}
HASH *
hnew(void)
{
register HASH *tb = (HASH*)safemalloc(sizeof(HASH));
tb->tbl_array = (HENT**) safemalloc(8 * sizeof(HENT*));
tb->tbl_fill = 0;
tb->tbl_max = 7;
hiterinit(tb); /* so each() will start off right */
memset(tb->tbl_array, 0, 8 * sizeof(HENT*));
return tb;
}
int
hiterinit(register HASH *tb)
{
tb->tbl_riter = -1;
tb->tbl_eiter = (HENT*)NULL;
return tb->tbl_fill;
}
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