xref: /dragonfly/usr.bin/rev/rev.c (revision 333227be)
1 /*-
2  * Copyright (c) 1987, 1992, 1993
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  * @(#) Copyright (c) 1987, 1992, 1993 The Regents of the University of California.  All rights reserved.
34  * @(#)rev.c	8.3 (Berkeley) 5/4/95
35  * $DragonFly: src/usr.bin/rev/rev.c,v 1.4 2003/11/03 19:31:32 eirikn Exp $
36  */
37 
38 #include <sys/types.h>
39 
40 #include <err.h>
41 #include <errno.h>
42 #include <stdio.h>
43 #include <stdlib.h>
44 #include <string.h>
45 #include <unistd.h>
46 
47 void usage(void);
48 
49 int
50 main(argc, argv)
51 	int argc;
52 	char *argv[];
53 {
54 	register char *filename, *p, *t;
55 	FILE *fp;
56 	size_t len;
57 	int ch, rval;
58 
59 	while ((ch = getopt(argc, argv, "")) != -1)
60 		switch(ch) {
61 		case '?':
62 		default:
63 			usage();
64 		}
65 
66 	argc -= optind;
67 	argv += optind;
68 
69 	fp = stdin;
70 	filename = "stdin";
71 	rval = 0;
72 	do {
73 		if (*argv) {
74 			if ((fp = fopen(*argv, "r")) == NULL) {
75 				warn("%s", *argv);
76 				rval = 1;
77 				++argv;
78 				continue;
79 			}
80 			filename = *argv++;
81 		}
82 		while ((p = fgetln(fp, &len)) != NULL) {
83 			if (p[len - 1] == '\n')
84 				--len;
85 			t = p + len - 1;
86 			for (t = p + len - 1; t >= p; --t)
87 				putchar(*t);
88 			putchar('\n');
89 		}
90 		if (ferror(fp)) {
91 			warn("%s", filename);
92 			rval = 1;
93 		}
94 		(void)fclose(fp);
95 	} while(*argv);
96 	exit(rval);
97 }
98 
99 void
100 usage()
101 {
102 	(void)fprintf(stderr, "usage: rev [file ...]\n");
103 	exit(1);
104 }
105