xref: /freebsd/usr.bin/basename/basename.c (revision a79b71281cd63ad7a6cc43a6d5673a2510b51630)
1 /*-
2  * Copyright (c) 1991, 1993, 1994
3  *	The Regents of the University of California.  All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  * 3. All advertising materials mentioning features or use of this software
14  *    must display the following acknowledgement:
15  *	This product includes software developed by the University of
16  *	California, Berkeley and its contributors.
17  * 4. Neither the name of the University nor the names of its contributors
18  *    may be used to endorse or promote products derived from this software
19  *    without specific prior written permission.
20  *
21  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31  * SUCH DAMAGE.
32  */
33 
34 #ifndef lint
35 static const char copyright[] =
36 "@(#) Copyright (c) 1991, 1993, 1994\n\
37 	The Regents of the University of California.  All rights reserved.\n";
38 #endif /* not lint */
39 
40 #ifndef lint
41 static const char sccsid[] = "@(#)basename.c	8.4 (Berkeley) 5/4/95";
42 #endif /* not lint */
43 
44 #include <stdio.h>
45 #include <stdlib.h>
46 #include <string.h>
47 #include <unistd.h>
48 
49 void usage __P((void));
50 
51 int
52 main(argc, argv)
53 	int argc;
54 	char **argv;
55 {
56 	char *p;
57 	int ch;
58 
59 	while ((ch = getopt(argc, argv, "")) != -1)
60 		switch(ch) {
61 		case '?':
62 		default:
63 			usage();
64 		}
65 	argc -= optind;
66 	argv += optind;
67 
68 	if (argc != 1 && argc != 2)
69 		usage();
70 
71 	/*
72 	 * (1) If string is // it is implementation defined whether steps (2)
73 	 *     through (5) are skipped or processed.
74 	 *
75 	 * (2) If string consists entirely of slash characters, string shall
76 	 *     be set to a single slash character.  In this case, skip steps
77 	 *     (3) through (5).
78 	 */
79 	for (p = *argv;; ++p) {
80 		if (!*p) {
81 			if (p > *argv)
82 				(void)printf("/\n");
83 			else
84 				(void)printf("\n");
85 			exit(0);
86 		}
87 		if (*p != '/')
88 			break;
89 	}
90 
91 	/*
92 	 * (3) If there are any trailing slash characters in string, they
93 	 *     shall be removed.
94 	 */
95 	for (; *p; ++p)
96 		continue;
97 	while (*--p == '/')
98 		continue;
99 	*++p = '\0';
100 
101 	/*
102 	 * (4) If there are any slash characters remaining in string, the
103 	 *     prefix of string up to an including the last slash character
104 	 *     in string shall be removed.
105 	 */
106 	while (--p >= *argv)
107 		if (*p == '/')
108 			break;
109 	++p;
110 
111 	/*
112 	 * (5) If the suffix operand is present, is not identical to the
113 	 *     characters remaining in string, and is identical to a suffix
114 	 *     of the characters remaining in string, the suffix suffix
115 	 *     shall be removed from string.
116 	 */
117 	if (*++argv) {
118 		int suffixlen, stringlen, off;
119 
120 		suffixlen = strlen(*argv);
121 		stringlen = strlen(p);
122 
123 		if (suffixlen < stringlen) {
124 			off = stringlen - suffixlen;
125 			if (!strcmp(p + off, *argv))
126 				p[off] = '\0';
127 		}
128 	}
129 	(void)printf("%s\n", p);
130 	exit(0);
131 }
132 
133 void
134 usage()
135 {
136 
137 	(void)fprintf(stderr, "usage: basename string [suffix]\n");
138 	exit(1);
139 }
140