usr.bin/rev/rev.c

   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 1.7 2006/07/30 06:49:39 dillon 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()
  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 }