xref: /dragonfly/usr.bin/rev/rev.c (revision ab709bfb)
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 1.8 2008/10/16 01:52:33 swildner Exp $
36  */
37 
38 #include <sys/types.h>
39 
40 #include <err.h>
41 #include <stdio.h>
42 #include <stdlib.h>
43 #include <unistd.h>
44 
45 static void	usage(void);
46 static int	dorev(FILE *, const char *);
47 
48 int
49 main(int argc, char **argv)
50 {
51 	FILE *fp;
52 	int ch, i, rval;
53 
54 	rval = 0;
55 
56 	while ((ch = getopt(argc, argv, "")) != -1)
57 		switch(ch) {
58 		case '?':
59 		default:
60 			usage();
61 		}
62 
63 	argc -= optind;
64 	argv += optind;
65 
66 	if (argc == 0)
67 		rval += dorev(stdin, "stdin");
68 
69 	for (i = 0; i < argc; ++i) {
70 		if ((fp = fopen(argv[i], "r")) != NULL) {
71 			rval += dorev(fp, argv[i]);
72 			fclose(fp);
73 		} else {
74 			warn("failed to open %s", argv[i]);
75 			rval++ ;
76 		}
77 	}
78 
79 	exit(rval != 0 ? 1 : 0);
80 }
81 
82 static void
83 usage(void)
84 {
85 	fprintf(stderr, "usage: rev [file ...]\n");
86 	exit(1);
87 }
88 
89 static int
90 dorev(FILE *fp, const char *filepath)
91 {
92 	const char *p, *t;
93 	size_t len;
94 
95 	while ((p = fgetln(fp, &len)) != NULL) {
96 			if (p[len - 1] == '\n')
97 				--len;
98 			for (t = p + len - 1; t >= p; --t)
99 				putchar(*t);
100 			putchar('\n');
101 	}
102 
103 	if (ferror(fp)) {
104 		warn("%s", filepath);
105 		/* Reset error indicator */
106 		clearerr(fp);
107 		return(1);
108 	}
109 
110 	return(0);
111 }
112