xref: /freebsd/usr.bin/rev/rev.c (revision 7f3dea244c40159a41ab22da77a434d7c5b5e85a)
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 
34 #ifndef lint
35 static char copyright[] =
36 "@(#) Copyright (c) 1987, 1992, 1993\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[] = "@(#)rev.c	8.3 (Berkeley) 5/4/95";
42 #endif /* not lint */
43 
44 #include <sys/types.h>
45 
46 #include <err.h>
47 #include <errno.h>
48 #include <stdio.h>
49 #include <stdlib.h>
50 #include <string.h>
51 #include <unistd.h>
52 
53 void usage __P((void));
54 
55 int
56 main(argc, argv)
57 	int argc;
58 	char *argv[];
59 {
60 	register char *filename, *p, *t;
61 	FILE *fp;
62 	size_t len;
63 	int ch, rval;
64 
65 	while ((ch = getopt(argc, argv, "")) != -1)
66 		switch(ch) {
67 		case '?':
68 		default:
69 			usage();
70 		}
71 
72 	argc -= optind;
73 	argv += optind;
74 
75 	fp = stdin;
76 	filename = "stdin";
77 	rval = 0;
78 	do {
79 		if (*argv) {
80 			if ((fp = fopen(*argv, "r")) == NULL) {
81 				warn("%s", *argv);
82 				rval = 1;
83 				++argv;
84 				continue;
85 			}
86 			filename = *argv++;
87 		}
88 		while ((p = fgetln(fp, &len)) != NULL) {
89 			if (p[len - 1] == '\n')
90 				--len;
91 			t = p + len - 1;
92 			for (t = p + len - 1; t >= p; --t)
93 				putchar(*t);
94 			putchar('\n');
95 		}
96 		if (ferror(fp)) {
97 			warn("%s", filename);
98 			rval = 1;
99 		}
100 		(void)fclose(fp);
101 	} while(*argv);
102 	exit(rval);
103 }
104 
105 void
106 usage()
107 {
108 	(void)fprintf(stderr, "usage: rev [file ...]\n");
109 	exit(1);
110 }
111