lsearch.c revision 105250 
1/*
2 * Initial implementation:
3 * Copyright (c) 2002 Robert Drehmel
4 * All rights reserved.
5 *
6 * As long as the above copyright statement and this notice remain
7 * unchanged, you can do what ever you want with this file.
8 */
9#include <sys/types.h>
10#include <sys/cdefs.h>
11__FBSDID("$FreeBSD: head/lib/libc/stdlib/lsearch.c 105250 2002-10-16 14:29:23Z robert $");
12
13#define	_SEARCH_PRIVATE
14#include <search.h>
15#include <stdint.h>	/* for uint8_t */
16#include <stdlib.h>	/* for NULL */
17#include <string.h>	/* for memcpy() prototype */
18
19static void *lwork(const void *, const void *, size_t *, size_t,
20    int (*)(const void *, const void *), int);
21
22void *lsearch(const void *key, void *base, size_t *nelp, size_t width,
23    int (*compar)(const void *, const void *))
24{
25
26	return (lwork(key, base, nelp, width, compar, 1));
27}
28
29void *lfind(const void *key, const void *base, size_t *nelp, size_t width,
30    int (*compar)(const void *, const void *))
31{
32
33	return (lwork(key, base, nelp, width, compar, 0));
34}
35
36static void *
37lwork(const void *key, const void *base, size_t *nelp, size_t width,
38    int (*compar)(const void *, const void *), int addelem)
39{
40	uint8_t *ep, *endp;
41
42	/*
43	 * Cast to an integer value first to avoid the warning for removing
44	 * 'const' via a cast.
45	 */
46	ep = (uint8_t *)(uintptr_t)base;
47	for (endp = (uint8_t *)(ep + width * *nelp); ep < endp; ep += width) {
48		if (compar(key, ep) == 0)
49			return (ep);
50	}
51
52	/* lfind() shall return when the key was not found. */
53	if (!addelem)
54		return (NULL);
55
56	/*
57	 * lsearch() adds the key to the end of the table and increments
58	 * the number of elements.
59	 */
60	memcpy(endp, key, width);
61	++*nelp;
62
63	return (endp);
64}
65