280 lines
6.7 KiB
C
280 lines
6.7 KiB
C
|
/*
|
||
|
|
* Copyright (c) 1992, 1993
|
||
|
|
* The Regents of the University of California. All rights reserved.
|
||
|
|
*
|
||
|
|
* This software was developed by the Computer Systems Engineering group
|
||
|
|
* at Lawrence Berkeley Laboratory under DARPA contract BG 91-66 and
|
||
|
|
* contributed to Berkeley.
|
||
|
|
*
|
||
|
|
* All advertising materials mentioning features or use of this software
|
||
|
|
* must display the following acknowledgement:
|
||
|
|
* This product includes software developed by the University of
|
||
|
|
* California, Lawrence Berkeley Laboratories.
|
||
|
|
*
|
||
|
|
* Redistribution and use in source and binary forms, with or without
|
||
|
|
* modification, are permitted provided that the following conditions
|
||
|
|
* are met:
|
||
|
|
* 1. Redistributions of source code must retain the above copyright
|
||
|
|
* notice, this list of conditions and the following disclaimer.
|
||
|
|
* 2. Redistributions in binary form must reproduce the above copyright
|
||
|
|
* notice, this list of conditions and the following disclaimer in the
|
||
|
|
* documentation and/or other materials provided with the distribution.
|
||
|
|
* 3. All advertising materials mentioning features or use of this software
|
||
|
|
* must display the following acknowledgement:
|
||
|
|
* This product includes software developed by the University of
|
||
|
|
* California, Berkeley and its contributors.
|
||
|
|
* 4. Neither the name of the University nor the names of its contributors
|
||
|
|
* may be used to endorse or promote products derived from this software
|
||
|
|
* without specific prior written permission.
|
||
|
|
*
|
||
|
|
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
|
||
|
|
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
|
||
|
|
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
|
||
|
|
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
|
||
|
|
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
|
||
|
|
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
|
||
|
|
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
|
||
|
|
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
|
||
|
|
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
|
||
|
|
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
|
||
|
|
* SUCH DAMAGE.
|
||
|
|
*
|
||
|
|
* @(#)hash.c 8.1 (Berkeley) 6/6/93
|
||
|
|
*/
|
||
|
|
|
||
|
|
#include <sys/param.h>
|
||
|
|
#include <stdlib.h>
|
||
|
|
#include <string.h>
|
||
|
|
#include "config.h"
|
||
|
|
|
||
|
|
/*
|
||
|
|
* Interned strings are kept in a hash table. By making each string
|
||
|
|
* unique, the program can compare strings by comparing pointers.
|
||
|
|
*/
|
||
|
|
struct hashent {
|
||
|
|
struct hashent *h_next; /* hash buckets are chained */
|
||
|
|
const char *h_name; /* the string */
|
||
|
|
u_int h_hash; /* its hash value */
|
||
|
|
void *h_value; /* other values (for name=value) */
|
||
|
|
};
|
||
|
|
struct hashtab {
|
||
|
|
size_t ht_size; /* size (power of 2) */
|
||
|
|
u_int ht_mask; /* == ht_size - 1 */
|
||
|
|
u_int ht_used; /* number of entries used */
|
||
|
|
u_int ht_lim; /* when to expand */
|
||
|
|
struct hashent **ht_tab; /* base of table */
|
||
|
|
};
|
||
|
|
static struct hashtab strings;
|
||
|
|
|
||
|
|
/*
|
||
|
|
* HASHFRACTION controls ht_lim, which in turn controls the average chain
|
||
|
|
* length. We allow a few entries, on average, as comparing them is usually
|
||
|
|
* cheap (the h_hash values prevent a strcmp).
|
||
|
|
*/
|
||
|
|
#define HASHFRACTION(sz) ((sz) * 3 / 2)
|
||
|
|
|
||
|
|
/* round up to next multiple of y, where y is a power of 2 */
|
||
|
|
#define ROUND(x, y) (((x) + (y) - 1) & ~((y) - 1))
|
||
|
|
|
||
|
|
/*
|
||
|
|
* Allocate space that will never be freed.
|
||
|
|
*/
|
||
|
|
static void *
|
||
|
|
poolalloc(size)
|
||
|
|
size_t size;
|
||
|
|
{
|
||
|
|
register char *p;
|
||
|
|
register size_t alloc;
|
||
|
|
static char *pool;
|
||
|
|
static size_t nleft;
|
||
|
|
|
||
|
|
if (nleft < size) {
|
||
|
|
/*
|
||
|
|
* Compute a `good' size to allocate via malloc.
|
||
|
|
* 16384 is a guess at a good page size for malloc;
|
||
|
|
* 32 is a guess at malloc's overhead.
|
||
|
|
*/
|
||
|
|
alloc = ROUND(size + 32, 16384) - 32;
|
||
|
|
p = emalloc(alloc);
|
||
|
|
nleft = alloc - size;
|
||
|
|
} else {
|
||
|
|
p = pool;
|
||
|
|
nleft -= size;
|
||
|
|
}
|
||
|
|
pool = p + size;
|
||
|
|
return (p);
|
||
|
|
}
|
||
|
|
|
||
|
|
/*
|
||
|
|
* Initialize a new hash table. The size must be a power of 2.
|
||
|
|
*/
|
||
|
|
static void
|
||
|
|
ht_init(ht, sz)
|
||
|
|
register struct hashtab *ht;
|
||
|
|
size_t sz;
|
||
|
|
{
|
||
|
|
register struct hashent **h;
|
||
|
|
register u_int n;
|
||
|
|
|
||
|
|
h = emalloc(sz * sizeof *h);
|
||
|
|
ht->ht_tab = h;
|
||
|
|
ht->ht_size = sz;
|
||
|
|
ht->ht_mask = sz - 1;
|
||
|
|
for (n = 0; n < sz; n++)
|
||
|
|
*h++ = NULL;
|
||
|
|
ht->ht_used = 0;
|
||
|
|
ht->ht_lim = HASHFRACTION(sz);
|
||
|
|
}
|
||
|
|
|
||
|
|
/*
|
||
|
|
* Expand an existing hash table.
|
||
|
|
*/
|
||
|
|
static void
|
||
|
|
ht_expand(ht)
|
||
|
|
register struct hashtab *ht;
|
||
|
|
{
|
||
|
|
register struct hashent *p, **h, **oldh, *q;
|
||
|
|
register u_int n, i;
|
||
|
|
|
||
|
|
n = ht->ht_size * 2;
|
||
|
|
h = emalloc(n * sizeof *h);
|
||
|
|
for (i = 0; i < n; i++)
|
||
|
|
h[i] = NULL;
|
||
|
|
oldh = ht->ht_tab;
|
||
|
|
n--;
|
||
|
|
for (i = ht->ht_size; i != 0; i--) {
|
||
|
|
for (p = *oldh++; p != NULL; p = q) {
|
||
|
|
q = p->h_next;
|
||
|
|
p->h_next = h[p->h_hash & n];
|
||
|
|
h[p->h_hash & n] = p;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
free(ht->ht_tab);
|
||
|
|
ht->ht_tab = h;
|
||
|
|
ht->ht_mask = n;
|
||
|
|
ht->ht_size = ++n;
|
||
|
|
ht->ht_lim = HASHFRACTION(n);
|
||
|
|
}
|
||
|
|
|
||
|
|
/*
|
||
|
|
* Make a new hash entry, setting its h_next to NULL.
|
||
|
|
*/
|
||
|
|
static inline struct hashent *
|
||
|
|
newhashent(name, h)
|
||
|
|
const char *name;
|
||
|
|
u_int h;
|
||
|
|
{
|
||
|
|
register struct hashent *hp;
|
||
|
|
register char *m;
|
||
|
|
|
||
|
|
m = poolalloc(sizeof(*hp) + ALIGNBYTES);
|
||
|
|
hp = (struct hashent *)ALIGN(m);
|
||
|
|
hp->h_name = name;
|
||
|
|
hp->h_hash = h;
|
||
|
|
hp->h_next = NULL;
|
||
|
|
return (hp);
|
||
|
|
}
|
||
|
|
|
||
|
|
/*
|
||
|
|
* Hash a string.
|
||
|
|
*/
|
||
|
|
static inline u_int
|
||
|
|
hash(str)
|
||
|
|
register const char *str;
|
||
|
|
{
|
||
|
|
register u_int h;
|
||
|
|
|
||
|
|
for (h = 0; *str;)
|
||
|
|
h = (h << 5) + h + *str++;
|
||
|
|
return (h);
|
||
|
|
}
|
||
|
|
|
||
|
|
void
|
||
|
|
initintern()
|
||
|
|
{
|
||
|
|
|
||
|
|
ht_init(&strings, 128);
|
||
|
|
}
|
||
|
|
|
||
|
|
/*
|
||
|
|
* Generate a single unique copy of the given string. We expect this
|
||
|
|
* function to be used frequently, so it should be fast.
|
||
|
|
*/
|
||
|
|
const char *
|
||
|
|
intern(s)
|
||
|
|
register const char *s;
|
||
|
|
{
|
||
|
|
register struct hashtab *ht;
|
||
|
|
register struct hashent *hp, **hpp;
|
||
|
|
register u_int h;
|
||
|
|
register char *p;
|
||
|
|
register size_t l;
|
||
|
|
|
||
|
|
ht = &strings;
|
||
|
|
h = hash(s);
|
||
|
|
hpp = &ht->ht_tab[h & ht->ht_mask];
|
||
|
|
for (; (hp = *hpp) != NULL; hpp = &hp->h_next)
|
||
|
|
if (hp->h_hash == h && strcmp(hp->h_name, s) == 0)
|
||
|
|
return (hp->h_name);
|
||
|
|
l = strlen(s) + 1;
|
||
|
|
p = poolalloc(l);
|
||
|
|
bcopy(s, p, l);
|
||
|
|
*hpp = newhashent(p, h);
|
||
|
|
if (++ht->ht_used > ht->ht_lim)
|
||
|
|
ht_expand(ht);
|
||
|
|
return (p);
|
||
|
|
}
|
||
|
|
|
||
|
|
struct hashtab *
|
||
|
|
ht_new()
|
||
|
|
{
|
||
|
|
register struct hashtab *ht;
|
||
|
|
|
||
|
|
ht = emalloc(sizeof *ht);
|
||
|
|
ht_init(ht, 8);
|
||
|
|
return (ht);
|
||
|
|
}
|
||
|
|
|
||
|
|
/*
|
||
|
|
* Insert and/or replace.
|
||
|
|
*/
|
||
|
|
int
|
||
|
|
ht_insrep(ht, nam, val, replace)
|
||
|
|
register struct hashtab *ht;
|
||
|
|
register const char *nam;
|
||
|
|
void *val;
|
||
|
|
int replace;
|
||
|
|
{
|
||
|
|
register struct hashent *hp, **hpp;
|
||
|
|
register u_int h;
|
||
|
|
|
||
|
|
h = hash(nam);
|
||
|
|
hpp = &ht->ht_tab[h & ht->ht_mask];
|
||
|
|
for (; (hp = *hpp) != NULL; hpp = &hp->h_next) {
|
||
|
|
if (hp->h_name == nam) {
|
||
|
|
if (replace)
|
||
|
|
hp->h_value = val;
|
||
|
|
return (1);
|
||
|
|
}
|
||
|
|
}
|
||
|
|
*hpp = hp = newhashent(nam, h);
|
||
|
|
hp->h_value = val;
|
||
|
|
return (0);
|
||
|
|
}
|
||
|
|
|
||
|
|
void *
|
||
|
|
ht_lookup(ht, nam)
|
||
|
|
register struct hashtab *ht;
|
||
|
|
register const char *nam;
|
||
|
|
{
|
||
|
|
register struct hashent *hp, **hpp;
|
||
|
|
register u_int h;
|
||
|
|
|
||
|
|
h = hash(nam);
|
||
|
|
hpp = &ht->ht_tab[h & ht->ht_mask];
|
||
|
|
for (; (hp = *hpp) != NULL; hpp = &hp->h_next)
|
||
|
|
if (hp->h_name == nam)
|
||
|
|
return (hp->h_value);
|
||
|
|
return (NULL);
|
||
|
|
}
|