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/*
* Hash Table
* Sumer Cip 2012
*/
#include "hashtab.h"
#include "mem.h"
static unsigned int
HHASH(_htab *ht, uintptr_t a)
{
a = (a ^ 61) ^ (a >> 16);
a = a + (a << 3);
a = a ^ (a >> 4);
a = a * 0x27d4eb2d;
a = a ^ (a >> 15);
return (a & ht->mask);
}
static int
_hgrow(_htab *ht)
{
int i;
_htab *dummy;
_hitem *p, *next, *it;
dummy = htcreate(ht->logsize+1);
if (!dummy)
return 0;
for(i=0; i<ht->realsize; i++) {
p = ht->_table[i];
while(p) {
next = p->next;
if (!hadd(dummy, p->key, p->val))
return 0;
it = hfind(dummy, p->key);
if (!it)
return 0;
it->free = p->free;
yfree(p);
p = next;
}
}
yfree(ht->_table);
ht->_table = dummy->_table;
ht->logsize = dummy->logsize;
ht->realsize = dummy->realsize;
ht->mask = dummy->mask;
yfree(dummy);
return 1;
}
_htab *
htcreate(int logsize)
{
int i;
_htab *ht;
ht = (_htab *)ymalloc(sizeof(_htab));
if (!ht)
return NULL;
ht->logsize = logsize;
ht->realsize = HSIZE(logsize);
ht->mask = HMASK(logsize);
ht->count = 0;
ht->freecount = 0;
ht->_table = (_hitem **)ymalloc(ht->realsize * sizeof(_hitem *));
if (!ht->_table) {
yfree(ht);
return NULL;
}
for(i=0; i<ht->realsize; i++)
ht->_table[i] = NULL;
return ht;
}
void
htdestroy(_htab *ht)
{
int i;
_hitem *p, *next;
for(i=0; i<ht->realsize; i++) {
p = ht->_table[i];
while(p) {
next = p->next;
yfree(p);
p = next;
}
}
yfree(ht->_table);
yfree(ht);
}
int
hadd(_htab *ht, uintptr_t key, uintptr_t val)
{
unsigned int h;
_hitem *new, *p;
h = HHASH(ht, key);
p = ht->_table[h];
new = NULL;
while(p) {
if ((p->key == key) && (!p->free))
return 0;
if (p->free)
new = p;
p = p->next;
}
// have a free slot?
if (new) {
new->key = key;
new->val = val;
new->free = 0;
ht->freecount--;
} else {
new = (_hitem *)ymalloc(sizeof(_hitem));
if (!new)
return 0;
new->key = key;
new->val = val;
new->next = ht->_table[h]; // add to front
new->free = 0;
ht->_table[h] = new;
ht->count++;
}
// need resizing?
if (((ht->count - ht->freecount) / (double)ht->realsize) >= HLOADFACTOR) {
ydprintf("hashtab resize.(%p)", ht);
if (!_hgrow(ht)) {
return 0;
}
}
return 1;
}
_hitem *
hfind(_htab *ht, uintptr_t key)
{
_hitem *p;
unsigned int h;
h = HHASH(ht, key);
p = ht->_table[h];
while(p) {
if ((p->key == key) && (!p->free)) {
return p;
}
p = p->next;
}
return NULL;
}
// enums non-free items
void
henum(_htab *ht, int (*enumfn)(_hitem *item, void *arg), void *arg)
{
int rc, i;
_hitem *p, *next;
for(i=0; i<ht->realsize; i++) {
p = ht->_table[i];
while(p) {
next = p->next;
if (!p->free) {
rc = enumfn(p, arg); // item may be freed.
if(rc)
return;
}
p = next;
}
}
}
int
hcount(_htab *ht)
{
return (ht->count - ht->freecount);
}
void
hfree(_htab *ht, _hitem *item)
{
if (!item->free) {
item->free = 1;
ht->freecount++;
}
}
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