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.\" Copyright (c) 1989, 1991, 1993 | |||
.\" The Regents of the University of California. 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 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. | |||
.\" | |||
.\" @(#)lsearch.3 8.1 (Berkeley) 6/4/93 | |||
.\" | |||
.Dd June 4, 1993 | |||
.Dt LSEARCH 3 | |||
.Os | |||
.Sh NAME | |||
.Nm lsearch , | |||
.Nm lfind | |||
.Nd linear searching routines | |||
.Sh SYNOPSIS | |||
.Ft char * | |||
.Fn lsearch "const void *key" "const void *base" "size_t *nelp" "size_t width" "int (*compar)(void *, void *)" | |||
.Ft char * | |||
.Fn lfind "const void *key" "const void *base" "size_t *nelp" "size_t width" "int (*compar)(void *, void *)" | |||
.Sh DESCRIPTION | |||
The functions | |||
.Fn lsearch , | |||
and | |||
.Fn lfind | |||
provide basic linear searching functionality. | |||
.Pp | |||
.Fa base | |||
is the pointer to the beginning of an array. | |||
The argument | |||
.Fa nelp | |||
is the current number of elements in the array, where each element | |||
is | |||
.Fa width | |||
bytes long. | |||
The | |||
.Fa compar | |||
function | |||
is a comparison routine which is used to compare two elements. | |||
It takes two arguments which point to the | |||
.Fa key | |||
object and to an array member, in that order, and must return an integer | |||
less than, equivalent to, or greater than zero if the | |||
.Fa key | |||
object is considered, respectively, to be less than, equal to, or greater | |||
than the array member. | |||
.Pp | |||
The | |||
.Fn lsearch | |||
and | |||
.Fn lfind | |||
functions | |||
return a pointer into the array referenced by | |||
.Fa base | |||
where | |||
.Fa key | |||
is located. | |||
If | |||
.Fa key | |||
does not exist, | |||
.Fn lfind | |||
will return a null pointer and | |||
.Fn lsearch | |||
will add it to the array. | |||
When an element is added to the array by | |||
.Fn lsearch | |||
the location referenced by the argument | |||
.Fa nelp | |||
is incremented by one. | |||
.Sh SEE ALSO | |||
.Xr bsearch 3 , | |||
.Xr db 3 | |||
.Sh STANDARDS | |||
The | |||
.Fn lsearch | |||
and | |||
.Fn lfind | |||
functions conform to the | |||
.St -p1003.1-01 | |||
and | |||
.St -xpg4.3 . | |||
specifications. |
@ -0,0 +1,90 @@ | |||
/* | |||
* Copyright (c) 1989, 1993 | |||
* The Regents of the University of California. All rights reserved. | |||
* | |||
* This code is derived from software contributed to Berkeley by | |||
* Roger L. Snyder. | |||
* | |||
* 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. | |||
*/ | |||
#if defined(LIBC_SCCS) && !defined(lint) | |||
static char sccsid[] = "@(#)lsearch.c 8.1 (Berkeley) 6/4/93"; | |||
#endif /* LIBC_SCCS and not lint */ | |||
#include <sys/types.h> | |||
#include <string.h> | |||
#include <search.h> | |||
typedef int (*cmp_fn_t)(const void *, const void *); | |||
static void *linear_base(const void *, const void *, size_t *, size_t, | |||
cmp_fn_t, int); | |||
void * | |||
lsearch(const void *key, const void *base, size_t *nelp, size_t width, | |||
cmp_fn_t compar) | |||
{ | |||
return(linear_base(key, base, nelp, width, compar, 1)); | |||
} | |||
void * | |||
lfind(const void *key, const void *base, size_t *nelp, size_t width, | |||
cmp_fn_t compar) | |||
{ | |||
return(linear_base(key, base, nelp, width, compar, 0)); | |||
} | |||
static void * | |||
linear_base(const void *key, const void *base, size_t *nelp, size_t width, | |||
cmp_fn_t compar, int add_flag) | |||
{ | |||
const char *element, *end; | |||
end = (const char *)base + *nelp * width; | |||
for (element = base; element < end; element += width) | |||
if (!compar(key, element)) /* key found */ | |||
return((void *)element); | |||
if (!add_flag) /* key not found */ | |||
return(NULL); | |||
/* | |||
* The UNIX System User's Manual, 1986 edition claims that | |||
* a NULL pointer is returned by lsearch with errno set | |||
* appropriately, if there is not enough room in the table | |||
* to add a new item. This can't be done as none of these | |||
* routines have any method of determining the size of the | |||
* table. This comment isn't in the 1986-87 System V | |||
* manual. | |||
*/ | |||
++*nelp; | |||
memcpy((void *)end, key, width); | |||
return((void *)end); | |||
} |