xref: /original-bsd/usr.bin/basename/basename.c (revision 3413c235)
1 /*-
2  * Copyright (c) 1991, 1993
3  *	The Regents of the University of California.  All rights reserved.
4  *
5  * %sccs.include.redist.c%
6  */
7 
8 #ifndef lint
9 static char copyright[] =
10 "@(#) Copyright (c) 1991, 1993\n\
11 	The Regents of the University of California.  All rights reserved.\n";
12 #endif /* not lint */
13 
14 #ifndef lint
15 static char sccsid[] = "@(#)basename.c	8.2 (Berkeley) 04/01/94";
16 #endif /* not lint */
17 
18 #include <stdio.h>
19 #include <stdlib.h>
20 #include <string.h>
21 
22 void usage __P((void));
23 
24 int
25 main(argc, argv)
26 	int argc;
27 	char **argv;
28 {
29 	char *p;
30 	int ch;
31 
32 	while ((ch = getopt(argc, argv, "")) != EOF)
33 		switch(ch) {
34 		case '?':
35 		default:
36 			usage();
37 		}
38 	argc -= optind;
39 	argv += optind;
40 
41 	if (argc != 1 && argc != 2)
42 		usage();
43 
44 	/*
45 	 * (1) If string is // it is implementation defined whether steps (2)
46 	 *     through (5) are skipped or processed.
47 	 *
48 	 * (2) If string consists entirely of slash characters, string shall
49 	 *     be set to a single slash character.  In this case, skip steps
50 	 *     (3) through (5).
51 	 */
52 	for (p = *argv;; ++p) {
53 		if (!*p) {
54 			if (p > *argv)
55 				(void)printf("/\n");
56 			else
57 				(void)printf("\n");
58 			exit(0);
59 		}
60 		if (*p != '/')
61 			break;
62 	}
63 
64 	/*
65 	 * (3) If there are any trailing slash characters in string, they
66 	 *     shall be removed.
67 	 */
68 	for (; *p; ++p)
69 		continue;
70 	while (*--p == '/')
71 		continue;
72 	*++p = '\0';
73 
74 	/*
75 	 * (4) If there are any slash characters remaining in string, the
76 	 *     prefix of string up to an including the last slash character
77 	 *     in string shall be removed.
78 	 */
79 	while (--p >= *argv)
80 		if (*p == '/')
81 			break;
82 	++p;
83 
84 	/*
85 	 * (5) If the suffix operand is present, is not identical to the
86 	 *     characters remaining in string, and is identical to a suffix
87 	 *     of the characters remaining in string, the suffix suffix
88 	 *     shall be removed from string.
89 	 */
90 	if (*++argv) {
91 		int suffixlen, stringlen, off;
92 
93 		suffixlen = strlen(*argv);
94 		stringlen = strlen(p);
95 
96 		if (suffixlen < stringlen) {
97 			off = stringlen - suffixlen;
98 			if (!strcmp(p + off, *argv))
99 				p[off] = '\0';
100 		}
101 	}
102 	(void)printf("%s\n", p);
103 	exit(0);
104 }
105 
106 void
107 usage()
108 {
109 
110 	(void)fprintf(stderr, "usage: basename string [suffix]\n");
111 	exit(1);
112 }
113