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/* $Header: hash.c,v 2.0 88/06/05 00:09:06 root Exp $
*
* $Log: hash.c,v $
* Revision 2.0 88/06/05 00:09:06 root
* Baseline version 2.0.
*
*/
#include "EXTERN.h"
#include "perl.h"
STR *
hfetch(tb,key)
register HASH *tb;
char *key;
{
register char *s;
register int i;
register int hash;
register HENT *entry;
if (!tb)
return Nullstr;
for (s=key, i=0, hash = 0;
/* while */ *s && i < COEFFSIZE;
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 Nullstr;
}
bool
hstore(tb,key,val)
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 && i < COEFFSIZE;
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;
safefree((char*)entry->hent_val);
entry->hent_val = val;
return TRUE;
}
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;
}
STR *
hdelete(tb,key)
register HASH *tb;
char *key;
{
register char *s;
register int i;
register int hash;
register HENT *entry;
register HENT **oentry;
STR *str;
if (!tb)
return Nullstr;
for (s=key, i=0, hash = 0;
/* while */ *s && i < COEFFSIZE;
s++, i++, hash *= 5) {
hash += *s * coeff[i];
}
oentry = &(tb->tbl_array[hash & tb->tbl_max]);
entry = *oentry;
i = 1;
for (; entry; i=0, oentry = &entry->hent_next, entry = *oentry) {
if (entry->hent_hash != hash) /* strings can't be equal */
continue;
if (strNE(entry->hent_key,key)) /* is this it? */
continue;
*oentry = entry->hent_next;
str = str_static(entry->hent_val);
hentfree(entry);
if (i)
tb->tbl_fill--;
return str;
}
return Nullstr;
}
hsplit(tb)
HASH *tb;
{
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*));
bzero((char*)&a[oldsize], 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()
{
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 */
bzero((char*)tb->tbl_array, 8 * sizeof(HENT*));
return tb;
}
void
hentfree(hent)
register HENT *hent;
{
if (!hent)
return;
str_free(hent->hent_val);
safefree(hent->hent_key);
safefree((char*)hent);
}
void
hclear(tb)
register HASH *tb;
{
register HENT *hent;
register HENT *ohent = Null(HENT*);
if (!tb)
return;
hiterinit(tb);
while (hent = hiternext(tb)) { /* concise but not very efficient */
hentfree(ohent);
ohent = hent;
}
hentfree(ohent);
tb->tbl_fill = 0;
bzero((char*)tb->tbl_array, (tb->tbl_max + 1) * sizeof(HENT*));
}
#ifdef NOTUSED
void
hfree(tb)
HASH *tb;
{
if (!tb)
return
hiterinit(tb);
while (hent = hiternext(tb)) {
hentfree(ohent);
ohent = hent;
}
hentfree(ohent);
safefree((char*)tb->tbl_array);
safefree((char*)tb);
}
#endif
#ifdef NOTUSED
hshow(tb)
register HASH *tb;
{
fprintf(stderr,"%5d %4d (%2d%%)\n",
tb->tbl_max+1,
tb->tbl_fill,
tb->tbl_fill * 100 / (tb->tbl_max+1));
}
#endif
hiterinit(tb)
register HASH *tb;
{
tb->tbl_riter = -1;
tb->tbl_eiter = Null(HENT*);
return tb->tbl_fill;
}
HENT *
hiternext(tb)
register HASH *tb;
{
register HENT *entry;
entry = tb->tbl_eiter;
do {
if (entry)
entry = entry->hent_next;
if (!entry) {
tb->tbl_riter++;
if (tb->tbl_riter > tb->tbl_max) {
tb->tbl_riter = -1;
break;
}
entry = tb->tbl_array[tb->tbl_riter];
}
} while (!entry);
tb->tbl_eiter = entry;
return entry;
}
char *
hiterkey(entry)
register HENT *entry;
{
return entry->hent_key;
}
STR *
hiterval(entry)
register HENT *entry;
{
return entry->hent_val;
}
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