freebsd-dev/lib/libc/stdlib/lsearch.c

65 lines
1.6 KiB
C
Raw Normal View History

/*
* Initial implementation:
* Copyright (c) 2002 Robert Drehmel
* All rights reserved.
*
* As long as the above copyright statement and this notice remain
* unchanged, you can do what ever you want with this file.
*/
#include <sys/types.h>
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#define _SEARCH_PRIVATE
#include <search.h>
#include <stdint.h> /* for uint8_t */
#include <stdlib.h> /* for NULL */
#include <string.h> /* for memcpy() prototype */
static void *lwork(const void *, const void *, size_t *, size_t,
int (*)(const void *, const void *), int);
void *lsearch(const void *key, void *base, size_t *nelp, size_t width,
int (*compar)(const void *, const void *))
{
return (lwork(key, base, nelp, width, compar, 1));
}
void *lfind(const void *key, const void *base, size_t *nelp, size_t width,
int (*compar)(const void *, const void *))
{
return (lwork(key, base, nelp, width, compar, 0));
}
static void *
lwork(const void *key, const void *base, size_t *nelp, size_t width,
int (*compar)(const void *, const void *), int addelem)
{
uint8_t *ep, *endp;
/*
* Cast to an integer value first to avoid the warning for removing
* 'const' via a cast.
*/
ep = (uint8_t *)(uintptr_t)base;
for (endp = (uint8_t *)(ep + width * *nelp); ep < endp; ep += width) {
if (compar(key, ep) == 0)
return (ep);
}
/* lfind() shall return when the key was not found. */
if (!addelem)
return (NULL);
/*
* lsearch() adds the key to the end of the table and increments
* the number of elements.
*/
memcpy(endp, key, width);
++*nelp;
return (endp);
}