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dirname.c revision 1.1.1.3 
      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 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 char sccsid[] = "@(#)dirname.c	8.4 (Berkeley) 5/4/95";
     42 #endif /* not lint */
     43 
     44 #include <stdio.h>
     45 #include <stdlib.h>
     46 #include <unistd.h>
     47 
     48 void usage __P((void));
     49 
     50 int
     51 main(argc, argv)
     52 	int argc;
     53 	char **argv;
     54 {
     55 	char *p;
     56 	int ch;
     57 
     58 	while ((ch = getopt(argc, argv, "")) != EOF)
     59 		switch(ch) {
     60 		case '?':
     61 		default:
     62 			usage();
     63 		}
     64 	argc -= optind;
     65 	argv += optind;
     66 
     67 	if (argc != 1)
     68 		usage();
     69 
     70 	/*
     71 	 * (1) If string is //, skip steps (2) through (5).
     72 	 * (2) If string consists entirely of slash characters, string
     73 	 *     shall be set to a single slash character.  In this case,
     74 	 *     skip steps (3) through (8).
     75 	 */
     76 	for (p = *argv;; ++p) {
     77 		if (!*p) {
     78 			if (p > *argv)
     79 				(void)printf("/\n");
     80 			else
     81 				(void)printf(".\n");
     82 			exit(0);
     83 		}
     84 		if (*p != '/')
     85 			break;
     86 	}
     87 
     88 	/*
     89 	 * (3) If there are any trailing slash characters in string, they
     90 	 *     shall be removed.
     91 	 */
     92 	for (; *p; ++p);
     93 	while (*--p == '/')
     94 		continue;
     95 	*++p = '\0';
     96 
     97 	/*
     98 	 * (4) If there are no slash characters remaining in string,
     99 	 *     string shall be set to a single period character.  In this
    100 	 *     case skip steps (5) through (8).
    101 	 *
    102 	 * (5) If there are any trailing nonslash characters in string,
    103 	 *     they shall be removed.
    104 	 */
    105 	while (--p >= *argv)
    106 		if (*p == '/')
    107 			break;
    108 	++p;
    109 	if (p == *argv) {
    110 		(void)printf(".\n");
    111 		exit(0);
    112 	}
    113 
    114 	/*
    115 	 * (6) If the remaining string is //, it is implementation defined
    116 	 *     whether steps (7) and (8) are skipped or processed.
    117 	 *
    118 	 * This case has already been handled, as part of steps (1) and (2).
    119 	 */
    120 
    121 	/*
    122 	 * (7) If there are any trailing slash characters in string, they
    123 	 *     shall be removed.
    124 	 */
    125 	while (--p >= *argv)
    126 		if (*p != '/')
    127 			break;
    128 	++p;
    129 
    130 	/*
    131 	 * (8) If the remaining string is empty, string shall be set to
    132 	 *     a single slash character.
    133 	 */
    134 	*p = '\0';
    135 	(void)printf("%s\n", p == *argv ? "/" : *argv);
    136 	exit(0);
    137 }
    138 
    139 void
    140 usage()
    141 {
    142 
    143 	(void)fprintf(stderr, "usage: dirname path\n");
    144 	exit(1);
    145 }
    146