xref: /freebsd/lib/libc/gen/basename.c (revision 4b9d605768acabc460aa6dcfe8a1f8db35b16794)
1 /*-
2  * Copyright (c) 2015-2016 Nuxi, https://nuxi.nl/
3  *
4  * Redistribution and use in source and binary forms, with or without
5  * modification, are permitted provided that the following conditions
6  * are met:
7  * 1. Redistributions of source code must retain the above copyright
8  *    notice, this list of conditions and the following disclaimer.
9  * 2. Redistributions in binary form must reproduce the above copyright
10  *    notice, this list of conditions and the following disclaimer in the
11  *    documentation and/or other materials provided with the distribution.
12  *
13  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
14  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
15  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
16  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
17  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
18  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
19  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
20  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
21  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
22  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
23  * SUCH DAMAGE.
24  */
25 
26 #include <libgen.h>
27 #include <string.h>
28 
29 char *
30 (basename)(char *path)
31 {
32 	char *ptr;
33 
34 	/*
35 	 * If path is a null pointer or points to an empty string,
36 	 * basename() shall return a pointer to the string ".".
37 	 */
38 	if (path == NULL || *path == '\0')
39 		return (__DECONST(char *, "."));
40 
41 	/* Find end of last pathname component and null terminate it. */
42 	ptr = path + strlen(path);
43 	while (ptr > path + 1 && *(ptr - 1) == '/')
44 		--ptr;
45 	*ptr-- = '\0';
46 
47 	/* Find beginning of last pathname component. */
48 	while (ptr > path && *(ptr - 1) != '/')
49 		--ptr;
50 	return (ptr);
51 }
52