Aren
/
NetBSD
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

add re-entrant versions of the hash functions based on the GNU api.

This commit is contained in:
christos 2011-09-14 23:33:51 +00:00
parent 89e01a7315
commit 05845f985a
3 changed files with 164 additions and 45 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

3
lib/libc/stdlib/Makefile.inc
View File

@ -1,4 +1,4 @@
# $NetBSD: Makefile.inc,v 1.77 2011/04/13 07:12:52 jruoho Exp $
# $NetBSD: Makefile.inc,v 1.78 2011/09/14 23:33:51 christos Exp $
# from: @(#)Makefile.inc 8.3 (Berkeley) 2/4/95
# stdlib sources
@ -65,6 +65,7 @@ MLINKS+=div.3 ldiv.3 \
MLINKS+=getenv.3 setenv.3 getenv.3 unsetenv.3 getenv.3 putenv.3
MLINKS+=getenv.3 getenv_r.3
MLINKS+=hcreate.3 hdestroy.3 hcreate.3 hsearch.3
MLINKS+=hcreate.3 hcreate_r.3 hcreate.3 hdestroy_r.3 hcreate.3 hsearch_r.3
MLINKS+=insque.3 remque.3
MLINKS+=lsearch.3 lfind.3
MLINKS+=malloc.3 calloc.3 malloc.3 realloc.3 malloc.3 free.3

103
lib/libc/stdlib/hcreate.3
View File

@ -1,4 +1,4 @@
.\" $NetBSD: hcreate.3,v 1.8 2010/05/01 06:18:03 jruoho Exp $
.\" $NetBSD: hcreate.3,v 1.9 2011/09/14 23:33:51 christos Exp $
.\"
.\" Copyright (c) 1999 The NetBSD Foundation, Inc.
.\" All rights reserved.
@ -27,13 +27,16 @@
.\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
.\" POSSIBILITY OF SUCH DAMAGE.
.\"
.Dd May 1, 2010
.Dd September 14, 2011
.Dt HCREATE 3
.Os
.Sh NAME
.Nm hcreate ,
.Nm hcreate_r ,
.Nm hdestroy ,
.Nm hsearch
.Nm hdestroy_r ,
.Nm hsearch ,
.Nm hsearch_r
.Nd manage hash search table
.Sh LIBRARY
.Lb libc
@ -41,16 +44,25 @@
.In search.h
.Ft int
.Fn hcreate "size_t nel"
.Ft int
.Fn hcreate_r "size_t nel" "struct hsearch_data *table"
.Ft void
.Fn hdestroy "void"
.Ft void
.Fn hdestroy_r "struct hsearch_data *table"
.Ft ENTRY *
.Fn hsearch "ENTRY item" "ACTION action"
.Ft int
.Fn hsearch_r "ENTRY item" "ACTION action" "ENTRY ** itemp" "struct hsearch_data *table"
.Sh DESCRIPTION
The
.Fn hcreate ,
.Fn hdestroy
.Fn hcreate_r ,
.Fn hdestroy ,
.Fn hdestroy_r
and
.Fn hsearch
.Fn hsearch ,
.Fn hsearch_r
functions manage hash search tables.
.Pp
The
@ -152,18 +164,46 @@ Typically the comparison
.Fa key
is allocated by using
.Xr strdup 3 .
.Pp
The
.Fn hcreate_r ,
.Fn hdestroy_r ,
and
.Fn hsearch_r
are re-entrant versions of the above functions that can operate on a table
supplied by the user.
The
.Fn hsearch_r
function returns
.Dv 0
if the action is
.Dv ENTER
and the element cannot be created,
.Dv 1
otherwise.
If the element exists or can be created, it will be placed in
.Fa itemp ,
otherwise
.Fa itemp
will be set to
.Dv NULL .
.Sh RETURN VALUES
If successful, the
.Fn hcreate
function returns a non-zero value.
Otherwise, a value of 0 is returned and
and
.Fn hcreate_r
function return a non-zero value.
Otherwise, a value of
.Dv 0
is returned and
.Va errno
is set to indicate the error.
.Pp
The
.Fn hdestroy
functions
returns no value.
and
.Fn hdestroy_r
functions return no value.
.Pp
If successful, the
.Fn hsearch
@ -182,16 +222,45 @@ 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.
.Pp
The
.Fn hsearch_r
function returns
.Dv 1
unless the table is full, when it returns
.Dv 0 .
If the
.Fn hsearch
returns
.Dv 0
or the element is not found,
.Va errno
is set to indicate the error.
.Sh ERRORS
The
.Fn hcreate
and
.Fn hcreate ,
.Fn hcreate_r ,
.Fn hsearch
and
.Fn hsearch_r
functions will fail if:
.Bl -tag -width Er
.It Bq Er ENOMEM
Insufficient memory is available.
.El
.Pp
The
.Fn hsearch
and
.Fn hsearch_r
functions will also fail if the action is
.Dv SEARCH and the element is not found:
.Bl -tag -width Er
.It Bq Er ESRCH
The
.Fa item
given is not found.
.El
.Sh SEE ALSO
.Xr bsearch 3 ,
.Xr lsearch 3 ,
@ -213,11 +282,21 @@ and
.Fn hsearch
functions first appeared in
.At V .
The
.Fn hcreate_r ,
.Fn hdestroy_r
and
.Fn hsearch_r
are
.Tn GNU
extensions.
.Sh CAVEATS
At least the following limitations can be mentioned:
.Bl -bullet
.It
The interface permits the use of only one hash table at a time.
The original, non-
.Tn GNU
interface permits the use of only one hash table at a time.
.It
Individual hash table entries can be added, but not deleted.
.It

103
lib/libc/stdlib/hcreate.c
View File

@ -1,4 +1,4 @@
/* $NetBSD: hcreate.c,v 1.6 2008/07/21 12:05:43 lukem Exp $ */
/* $NetBSD: hcreate.c,v 1.7 2011/09/14 23:33:51 christos Exp $ */
/*
* Copyright (c) 2001 Christopher G. Demetriou
@ -48,7 +48,7 @@
#include <sys/cdefs.h>
#if defined(LIBC_SCCS) && !defined(lint)
__RCSID("$NetBSD: hcreate.c,v 1.6 2008/07/21 12:05:43 lukem Exp $");
__RCSID("$NetBSD: hcreate.c,v 1.7 2011/09/14 23:33:51 christos Exp $");
#endif /* LIBC_SCCS and not lint */
#if !defined(lint)
@ -88,21 +88,28 @@ SLIST_HEAD(internal_head, internal_entry);
/* 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;
static struct hsearch_data htable;
int
hcreate(size_t nel)
{
size_t idx;
unsigned int p2;
_DIAGASSERT(htable.table == NULL);
/* Make sure this isn't called when a table already exists. */
_DIAGASSERT(htable == NULL);
if (htable != NULL) {
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)
@ -121,76 +128,108 @@ hcreate(size_t nel)
}
/* Allocate the table. */
htablesize = nel;
htable = malloc(htablesize * sizeof htable[0]);
if (htable == NULL) {
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 < htablesize; idx++)
SLIST_INIT(&htable[idx]);
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;
_DIAGASSERT(htable != NULL);
if (htable == NULL)
if (head == NULL)
return;
for (idx = 0; idx < htablesize; idx++) {
while (!SLIST_EMPTY(&htable[idx])) {
ie = SLIST_FIRST(&htable[idx]);
SLIST_REMOVE_HEAD(&htable[idx], link);
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(htable);
htable = NULL;
free(table);
}
ENTRY *
hsearch(ENTRY item, ACTION action)
{
struct internal_head *head;
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(htable != NULL);
_DIAGASSERT(item.key != NULL);
_DIAGASSERT(action == ENTER || action == FIND);
p = head->table;
table = p;
len = strlen(item.key);
hashval = (*__default_hash)(item.key, len);
head = &htable[hashval & (htablesize - 1)];
ie = SLIST_FIRST(head);
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)
return &ie->ent;
else if (action == FIND)
return NULL;
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 NULL;
return 0;
ie->ent.key = item.key;
ie->ent.data = item.data;
SLIST_INSERT_HEAD(head, ie, link);
return &ie->ent;
SLIST_INSERT_HEAD(chain, ie, link);
*itemp = &ie->ent;
head->filled++;
return 1;
}