picrin/extlib/xhash/xhash.h

101 lines
1.6 KiB
C

#ifndef XHASH_H__
#define XHASH_H__
/*
* Copyright (c) 2013 by Yuichi Nishiwaki <yuichi.nishiwaki@gmail.com>
*/
#include <stdlib.h>
#include <string.h>
/* simple string to int hash table */
#define XHASH_INIT_SIZE 11
struct xh_entry {
struct xh_entry *next;
const char *key;
int val;
};
struct xhash {
struct xh_entry **buckets;
size_t size;
};
static inline struct xhash *
xh_new()
{
struct xhash *x;
x = (struct xhash *)malloc(sizeof(struct xhash));
x->size = XHASH_INIT_SIZE;
x->buckets = (struct xh_entry **)calloc(XHASH_INIT_SIZE, sizeof(struct xh_entry *));
return x;
}
static int
xh_hash(const char *str)
{
int hash = 0;
while (*str) {
hash = hash * 31 + *str++;
}
return hash;
}
static inline struct xh_entry *
xh_get(struct xhash *x, const char *key)
{
int idx;
struct xh_entry *e;
idx = xh_hash(key) % x->size;
for (e = x->buckets[idx]; e; e = e->next) {
if (strcmp(key, e->key) == 0)
return e;
}
return NULL;
}
static inline struct xh_entry *
xh_put(struct xhash *x, const char *key, int val)
{
int idx;
struct xh_entry *e;
if ((e = xh_get(x, key))) {
e->val = val;
return e;
}
idx = xh_hash(key) % x->size;
e = (struct xh_entry *)malloc(sizeof(struct xh_entry));
e->next = x->buckets[idx];
e->key = strdup(key);
e->val = val;
return x->buckets[idx] = e;
}
static inline void
xh_destory(struct xhash *x)
{
int i;
struct xh_entry *e, *d;
for (i = 0; i < x->size; ++i) {
e = x->buckets[i];
while (e) {
d = e->next;
free((void*)e->key);
free(e);
e = d;
}
}
free(x);
}
#endif