Now passes the regress tests.OPENBSD_3_6
@ -0,0 +1,195 @@ | |||||
.\" $OpenBSD: hcreate.3,v 1.1 2004/06/24 04:43:33 millert Exp $ | |||||
.\" $NetBSD: hcreate.3,v 1.6 2003/04/16 13:34:46 wiz Exp $ | |||||
.\" | |||||
.\" Copyright (c) 1999 The NetBSD Foundation, Inc. | |||||
.\" All rights reserved. | |||||
.\" | |||||
.\" This code is derived from software contributed to The NetBSD Foundation | |||||
.\" by Klaus Klein. | |||||
.\" | |||||
.\" 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 NetBSD | |||||
.\" Foundation, Inc. and its contributors. | |||||
.\" 4. Neither the name of The NetBSD Foundation 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 NETBSD FOUNDATION, INC. 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 FOUNDATION 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. | |||||
.\" | |||||
.Dd February 13, 2001 | |||||
.Dt HCREATE 3 | |||||
.Os | |||||
.Sh NAME | |||||
.Nm hcreate , | |||||
.Nm hdestroy , | |||||
.Nm hsearch | |||||
.Nd manage hash search table | |||||
.Sh SYNOPSIS | |||||
.In search.h | |||||
.Ft int | |||||
.Fn hcreate "size_t nel" | |||||
.Ft void | |||||
.Fn hdestroy "void" | |||||
.Ft ENTRY * | |||||
.Fn hsearch "ENTRY item" "ACTION action" | |||||
.Sh DESCRIPTION | |||||
The | |||||
.Fn hcreate , | |||||
.Fn hdestroy | |||||
and | |||||
.Fn hsearch | |||||
functions manage hash search tables. | |||||
.Pp | |||||
The | |||||
.Fn hcreate | |||||
function allocates and initializes the table. | |||||
The | |||||
.Fa nel | |||||
argument specifies an estimate of the maximum number of entries to be held | |||||
by the table. | |||||
Unless further memory allocation fails, supplying an insufficient | |||||
.Fa nel | |||||
value will not result in functional harm, although a performance degradation | |||||
may occur. | |||||
Initialization using the | |||||
.Fn hcreate | |||||
function is mandatory prior to any access operations using | |||||
.Fn hsearch . | |||||
.Pp | |||||
The | |||||
.Fn hdestroy | |||||
function destroys a table previously created using | |||||
.Fn hcreate . | |||||
After a call to | |||||
.Fn hdestroy , | |||||
the data can no longer be accessed. | |||||
.Pp | |||||
The | |||||
.Fn hsearch | |||||
function is used to search to the hash table. | |||||
It returns a pointer into the | |||||
hash table indicating the address of an item. | |||||
The | |||||
.Fa item | |||||
argument is of type | |||||
.Dv ENTRY , | |||||
a structural type which contains the following members: | |||||
.Bl -tag -compact -offset indent -width voidX*dataXX | |||||
.It Fa char *key | |||||
comparison key. | |||||
.It Fa void *data | |||||
pointer to data associated with | |||||
.Fa key . | |||||
.El | |||||
.Pp | |||||
The key comparison function used by | |||||
.Fn hsearch | |||||
is | |||||
.Xr strcmp 3 . | |||||
.Pp | |||||
The | |||||
.Fa action | |||||
argument is of type | |||||
.Dv ACTION , | |||||
an enumeration type which defines the following values: | |||||
.Bl -tag -compact -offset indent -width ENTERXX | |||||
.It Dv ENTER | |||||
Insert | |||||
.Fa item | |||||
into the hash table. | |||||
If an existing item with the same key is found, it is not replaced. | |||||
Note that the | |||||
.Fa key | |||||
and | |||||
.Fa data | |||||
elements of | |||||
.Fa item | |||||
are used directly by the new table entry. | |||||
The storage for the | |||||
key must not be modified during the lifetime of the hash table. | |||||
.It Dv FIND | |||||
Search the hash table without inserting | |||||
.Fa item . | |||||
.El | |||||
.Sh RETURN VALUES | |||||
If successful, the | |||||
.Fn hcreate | |||||
function returns a non-zero value. | |||||
Otherwise, a value of 0 is returned and | |||||
.Va errno | |||||
is set to indicate the error. | |||||
.Pp | |||||
The | |||||
.Fn hdestroy | |||||
functions | |||||
returns no value. | |||||
.Pp | |||||
If successful, the | |||||
.Fn hsearch | |||||
function returns a pointer to hash table entry matching | |||||
the provided key. | |||||
If the action is | |||||
.Dv FIND | |||||
and the item was not found, or if the action is | |||||
.Dv ENTER | |||||
and the insertion failed, | |||||
.Dv NULL | |||||
is returned and | |||||
.Va errno | |||||
is set to indicate the error. | |||||
If the action is | |||||
.Dv ENTER | |||||
and an entry already existed in the table matching the given | |||||
key, the existing entry is returned and is not replaced. | |||||
.Sh ERRORS | |||||
The | |||||
.Fn hcreate | |||||
and | |||||
.Fn hsearch | |||||
functions will fail if: | |||||
.Bl -tag -width Er | |||||
.It Bq Er ENOMEM | |||||
Insufficient memory is available. | |||||
.El | |||||
.Sh SEE ALSO | |||||
.Xr bsearch 3 , | |||||
.Xr lsearch 3 , | |||||
.Xr malloc 3 , | |||||
.Xr strcmp 3 | |||||
.Sh STANDARDS | |||||
The | |||||
.Fn hcreate , | |||||
.Fn hdestroy | |||||
and | |||||
.Fn hsearch | |||||
functions conform to | |||||
.St -xpg4.2 . | |||||
.Sh HISTORY | |||||
The | |||||
.Fn hcreate , | |||||
.Fn hdestroy | |||||
and | |||||
.Fn hsearch | |||||
functions first appeared in | |||||
.At V . | |||||
.Sh BUGS | |||||
The interface permits the use of only one hash table at a time. |
@ -0,0 +1,200 @@ | |||||
/* $OpenBSD: hcreate.c,v 1.1 2004/06/24 04:43:33 millert Exp $ */ | |||||
/* $NetBSD: hcreate.c,v 1.5 2004/04/23 02:48:12 simonb 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. All advertising materials mentioning features or use of this software | |||||
* must display the following acknowledgement: | |||||
* This product includes software developed for the | |||||
* NetBSD Project. See http://www.NetBSD.org/ for | |||||
* information about NetBSD. | |||||
* 4. 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... | |||||
*/ | |||||
#ifndef lint | |||||
static const char copyright[] = | |||||
"@(#) Copyright (c) 2001 Christopher G. Demetriou. All rights reserved.\n"; | |||||
#endif /* not lint */ | |||||
#ifndef lint | |||||
static const char rcsid[] = "$OpenBSD: hcreate.c,v 1.1 2004/06/24 04:43:33 millert Exp $"; | |||||
#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> | |||||
#ifndef _DIAGASSERT | |||||
#define _DIAGASSERT | |||||
#endif | |||||
/* | |||||
* 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 internal_head *htable; | |||||
static size_t htablesize; | |||||
int | |||||
hcreate(size_t nel) | |||||
{ | |||||
size_t idx; | |||||
unsigned int p2; | |||||
/* Make sure this isn't called when a table already exists. */ | |||||
_DIAGASSERT(htable == NULL); | |||||
if (htable != NULL) { | |||||
errno = EINVAL; | |||||
return 0; | |||||
} | |||||
/* 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. */ | |||||
htablesize = nel; | |||||
htable = malloc(htablesize * sizeof htable[0]); | |||||
if (htable == NULL) { | |||||
errno = ENOMEM; | |||||
return 0; | |||||
} | |||||
/* Initialize it. */ | |||||
for (idx = 0; idx < htablesize; idx++) | |||||
SLIST_INIT(&htable[idx]); | |||||
return 1; | |||||
} | |||||
void | |||||
hdestroy(void) | |||||
{ | |||||
struct internal_entry *ie; | |||||
size_t idx; | |||||
_DIAGASSERT(htable != NULL); | |||||
if (htable == NULL) | |||||
return; | |||||
for (idx = 0; idx < htablesize; idx++) { | |||||
while (!SLIST_EMPTY(&htable[idx])) { | |||||
ie = SLIST_FIRST(&htable[idx]); | |||||
SLIST_REMOVE_HEAD(&htable[idx], link); | |||||
free(ie->ent.key); | |||||
free(ie); | |||||
} | |||||
} | |||||
free(htable); | |||||
htable = NULL; | |||||
} | |||||
ENTRY * | |||||
hsearch(ENTRY item, ACTION action) | |||||
{ | |||||
struct internal_head *head; | |||||
struct internal_entry *ie; | |||||
uint32_t hashval; | |||||
size_t len; | |||||
_DIAGASSERT(htable != NULL); | |||||
_DIAGASSERT(item.key != NULL); | |||||
_DIAGASSERT(action == ENTER || action == FIND); | |||||
len = strlen(item.key); | |||||
hashval = (*__default_hash)(item.key, len); | |||||
head = &htable[hashval & (htablesize - 1)]; | |||||
ie = SLIST_FIRST(head); | |||||
while (ie != NULL) { | |||||
if (strcmp(ie->ent.key, item.key) == 0) | |||||
break; | |||||
ie = SLIST_NEXT(ie, link); | |||||
} | |||||
if (ie != NULL) | |||||
return &ie->ent; | |||||
else if (action == FIND) | |||||
return NULL; | |||||
ie = malloc(sizeof *ie); | |||||
if (ie == NULL) | |||||
return NULL; | |||||
ie->ent.key = item.key; | |||||
ie->ent.data = item.data; | |||||
SLIST_INSERT_HEAD(head, ie, link); | |||||
return &ie->ent; | |||||
} |