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/* $Id: hashtab.h,v 1.1 1999/03/23 05:58:53 dm Exp $ */
/*
*
* Copyright (C) 1998, 1999 David Mazieres (dm@uun.org)
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation; either version 2, or (at
* your option) any later version.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
* USA
*
*/
#ifndef _HASHTAB_H_
#define _HASHTAB_H_ 1
#include <stddef.h>
struct hashtab_entry {
void *hte_next;
void **hte_prev;
u_int hte_hval;
};
struct _hashtab {
u_int ht_buckets;
u_int ht_entries;
void **ht_tab;
};
#define HASHSEED 5381
static inline u_int
hash (u_int seed, const u_char *key, int len)
{
const u_char *end;
for (end = key + len; key < end; key++)
seed = ((seed << 5) + seed) ^ *key;
return seed;
}
extern void _hashtab_grow (struct _hashtab *, u_int);
extern const u_int exp2primes[];
#define hashtab_decl(name, type, field) \
struct name { \
struct _hashtab ht; \
}; \
static inline void \
name ## _init (struct name *_htp) \
{ \
struct _hashtab *htp = &_htp->ht; \
htp->ht_entries = 0; \
htp->ht_buckets = 0; \
htp->ht_tab = NULL; \
} \
static inline void \
name ## _clear (struct name *_htp) \
{ \
struct _hashtab *htp = &_htp->ht; \
xfree (htp->ht_tab); \
} \
static inline void \
name ## _insert (struct name *_htp, struct type *elm, u_int hval) \
{ \
struct _hashtab *htp = &_htp->ht; \
u_int bn; \
struct type *np; \
\
if (++htp->ht_entries >= htp->ht_buckets) \
_hashtab_grow (htp, offsetof (struct type, field)); \
elm->field.hte_hval = hval; \
\
bn = hval % htp->ht_buckets; \
if ((np = htp->ht_tab[bn])) \
np->field.hte_prev = &elm->field.hte_next; \
elm->field.hte_next = np; \
elm->field.hte_prev = &htp->ht_tab[bn]; \
htp->ht_tab[bn] = elm; \
} \
static inline void \
name ## _delete (struct name *_htp, struct type *elm) \
{ \
struct _hashtab *htp = &_htp->ht; \
htp->ht_entries--; \
if (elm->field.hte_next) \
((struct type *) elm->field.hte_next)->field.hte_prev \
= elm->field.hte_prev; \
*elm->field.hte_prev = elm->field.hte_next; \
} \
static inline struct type * \
name ## _chain (struct name *_htp, u_int hval) \
{ \
struct _hashtab *htp = &_htp->ht; \
return htp->ht_buckets ? htp->ht_tab[hval % htp->ht_buckets] : 0; \
} \
static inline struct type * \
name ## _next (struct type *elm) \
{ \
return elm->field.hte_next; \
} \
static inline void \
name ## _traverse (struct name *_htp, \
void (*fn) (void *, struct type *), \
void *arg) \
{ \
struct _hashtab *htp = &_htp->ht; \
struct type *e, *ne; \
u_int i; \
for (i = 0; i < htp->ht_buckets; i++) \
for (e = htp->ht_tab[i]; e; e = ne) { \
ne = e->field.hte_next; \
fn (arg, e); \
} \
} \
static inline u_int \
name ## _size (struct name *_htp) \
{ \
struct _hashtab *htp = &_htp->ht; \
return htp->ht_entries; \
} \
struct name
static inline u_int
hash_string (const char *_key)
{
const u_char *key = (const u_char *) _key;
u_int seed = 5381;
while (*key)
seed = ((seed << 5) + seed) ^ *key++;
return seed;
}
#endif /* _HASHTAB_H_ */
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