minix/lib/libc/stdlib/hcreate.c
Lionel Sambuc f14fb60209 Libraries updates and cleanup
* Updating common/lib
 * Updating lib/csu
 * Updating lib/libc
 * Updating libexec/ld.elf_so
 * Corrected test on __minix in featuretest to actually follow the
   meaning of the comment.
 * Cleaned up _REENTRANT-related defintions.
 * Disabled -D_REENTRANT for libfetch
 * Removing some unneeded __NBSD_LIBC defines and tests

Change-Id: Ic1394baef74d11b9f86b312f5ff4bbc3cbf72ce2
2013-01-14 11:36:26 +01:00

230 lines
5.5 KiB
C

/* $NetBSD: hcreate.c,v 1.8 2011/09/17 16:54:39 christos Exp $ */
/*
* Copyright (c) 2001 Christopher G. Demetriou
* All rights reserved.
*
* 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. The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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.
*
* <<Id: LICENSE,v 1.2 2000/06/14 15:57:33 cgd Exp>>
*/
/*
* hcreate() / hsearch() / hdestroy()
*
* SysV/XPG4 hash table functions.
*
* Implementation done based on NetBSD manual page and Solaris manual page,
* plus my own personal experience about how they're supposed to work.
*
* I tried to look at Knuth (as cited by the Solaris manual page), but
* nobody had a copy in the office, so...
*/
#include <sys/cdefs.h>
#if defined(LIBC_SCCS) && !defined(lint)
__RCSID("$NetBSD: hcreate.c,v 1.8 2011/09/17 16:54:39 christos Exp $");
#endif /* LIBC_SCCS and not lint */
#if !defined(lint)
__COPYRIGHT("@(#) Copyright (c) 2001\
Christopher G. Demetriou. All rights reserved.");
#endif /* not lint */
#include "namespace.h"
#include <assert.h>
#include <errno.h>
#include <inttypes.h>
#include <search.h>
#include <stdlib.h>
#include <string.h>
#include <sys/queue.h>
/*
* DO NOT MAKE THIS STRUCTURE LARGER THAN 32 BYTES (4 ptrs on 64-bit
* ptr machine) without adjusting MAX_BUCKETS_LG2 below.
*/
struct internal_entry {
SLIST_ENTRY(internal_entry) link;
ENTRY ent;
};
SLIST_HEAD(internal_head, internal_entry);
#define MIN_BUCKETS_LG2 4
#define MIN_BUCKETS (1 << MIN_BUCKETS_LG2)
/*
* max * sizeof internal_entry must fit into size_t.
* assumes internal_entry is <= 32 (2^5) bytes.
*/
#define MAX_BUCKETS_LG2 (sizeof (size_t) * 8 - 1 - 5)
#define MAX_BUCKETS ((size_t)1 << MAX_BUCKETS_LG2)
/* Default hash function, from db/hash/hash_func.c */
extern u_int32_t (*__default_hash)(const void *, size_t);
static struct hsearch_data htable;
int
hcreate(size_t nel)
{
_DIAGASSERT(htable.table == NULL);
/* Make sure this isn't called when a table already exists. */
if (htable.table != NULL) {
errno = EINVAL;
return 0;
}
return hcreate_r(nel, &htable);
}
int
hcreate_r(size_t nel, struct hsearch_data *head)
{
struct internal_head *table;
size_t idx;
unsigned int p2;
void *p;
/* If nel is too small, make it min sized. */
if (nel < MIN_BUCKETS)
nel = MIN_BUCKETS;
/* If it's too large, cap it. */
if (nel > MAX_BUCKETS)
nel = MAX_BUCKETS;
/* If it's is not a power of two in size, round up. */
if ((nel & (nel - 1)) != 0) {
for (p2 = 0; nel != 0; p2++)
nel >>= 1;
_DIAGASSERT(p2 <= MAX_BUCKETS_LG2);
nel = 1 << p2;
}
/* Allocate the table. */
head->size = nel;
head->filled = 0;
p = malloc(nel * sizeof table[0]);
if (p == NULL) {
errno = ENOMEM;
return 0;
}
head->table = p;
table = p;
/* Initialize it. */
for (idx = 0; idx < nel; idx++)
SLIST_INIT(&table[idx]);
return 1;
}
void
hdestroy(void)
{
_DIAGASSERT(htable.table != NULL);
hdestroy_r(&htable);
}
void
hdestroy_r(struct hsearch_data *head)
{
struct internal_entry *ie;
size_t idx;
void *p;
struct internal_head *table;
if (head == NULL)
return;
p = head->table;
head->table = NULL;
table = p;
for (idx = 0; idx < head->size; idx++) {
while (!SLIST_EMPTY(&table[idx])) {
ie = SLIST_FIRST(&table[idx]);
SLIST_REMOVE_HEAD(&table[idx], link);
free(ie->ent.key);
free(ie);
}
}
free(table);
}
ENTRY *
hsearch(ENTRY item, ACTION action)
{
ENTRY *ep;
_DIAGASSERT(htable.table != NULL);
(void)hsearch_r(item, action, &ep, &htable);
return ep;
}
int
hsearch_r(ENTRY item, ACTION action, ENTRY **itemp, struct hsearch_data *head)
{
struct internal_head *table, *chain;
struct internal_entry *ie;
uint32_t hashval;
size_t len;
void *p;
_DIAGASSERT(item.key != NULL);
_DIAGASSERT(action == ENTER || action == FIND);
p = head->table;
table = p;
len = strlen(item.key);
hashval = (*__default_hash)(item.key, len);
chain = &table[hashval & (head->size - 1)];
ie = SLIST_FIRST(chain);
while (ie != NULL) {
if (strcmp(ie->ent.key, item.key) == 0)
break;
ie = SLIST_NEXT(ie, link);
}
if (ie != NULL) {
*itemp = &ie->ent;
return 1;
} else if (action == FIND) {
*itemp = NULL;
errno = ESRCH;
return 1;
}
ie = malloc(sizeof *ie);
if (ie == NULL)
return 0;
ie->ent.key = item.key;
ie->ent.data = item.data;
SLIST_INSERT_HEAD(chain, ie, link);
*itemp = &ie->ent;
head->filled++;
return 1;
}