@ -0,0 +1,107 @@ | |||||
.\" 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); | |||||
} |