Home | History | Annotate | Line # | Download | only in fold
fold.c revision 1.1 
      1 /*-
      2  * Copyright (c) 1990 The Regents of the University of California.
      3  * All rights reserved.
      4  *
      5  * This code is derived from software contributed to Berkeley by
      6  * Kevin Ruddy.
      7  *
      8  * Redistribution and use in source and binary forms, with or without
      9  * modification, are permitted provided that the following conditions
     10  * are met:
     11  * 1. Redistributions of source code must retain the above copyright
     12  *    notice, this list of conditions and the following disclaimer.
     13  * 2. Redistributions in binary form must reproduce the above copyright
     14  *    notice, this list of conditions and the following disclaimer in the
     15  *    documentation and/or other materials provided with the distribution.
     16  * 3. All advertising materials mentioning features or use of this software
     17  *    must display the following acknowledgement:
     18  *	This product includes software developed by the University of
     19  *	California, Berkeley and its contributors.
     20  * 4. Neither the name of the University nor the names of its contributors
     21  *    may be used to endorse or promote products derived from this software
     22  *    without specific prior written permission.
     23  *
     24  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     25  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     26  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     27  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     28  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     29  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     30  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     31  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     32  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     33  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     34  * SUCH DAMAGE.
     35  */
     36 
     37 #ifndef lint
     38 char copyright[] =
     39 "@(#) Copyright (c) 1990 The Regents of the University of California.\n\
     40  All rights reserved.\n";
     41 #endif /* not lint */
     42 
     43 #ifndef lint
     44 static char sccsid[] = "@(#)fold.c	5.5 (Berkeley) 6/1/90";
     45 #endif /* not lint */
     46 
     47 #include <stdio.h>
     48 #include <string.h>
     49 
     50 #define	DEFLINEWIDTH	80
     51 
     52 main(argc, argv)
     53 	int argc;
     54 	char **argv;
     55 {
     56 	extern int errno, optind;
     57 	extern char *optarg;
     58 	register int ch;
     59 	int width;
     60 	char *p;
     61 
     62 	width = -1;
     63 	while ((ch = getopt(argc, argv, "0123456789w:")) != EOF)
     64 		switch (ch) {
     65 		case 'w':
     66 			if ((width = atoi(optarg)) <= 0) {
     67 				(void)fprintf(stderr,
     68 				    "fold: illegal width value.\n");
     69 				exit(1);
     70 			}
     71 			break;
     72 		case '0': case '1': case '2': case '3': case '4':
     73 		case '5': case '6': case '7': case '8': case '9':
     74 			if (width == -1) {
     75 				p = argv[optind - 1];
     76 				if (p[0] == '-' && p[1] == ch && !p[2])
     77 					width = atoi(++p);
     78 				else
     79 					width = atoi(argv[optind] + 1);
     80 			}
     81 			break;
     82 		default:
     83 			(void)fprintf(stderr,
     84 			    "usage: fold [-w width] [file ...]\n");
     85 			exit(1);
     86 		}
     87 	argv += optind;
     88 	argc -= optind;
     89 
     90 	if (width == -1)
     91 		width = DEFLINEWIDTH;
     92 	if (!*argv)
     93 		fold(width);
     94 	else for (; *argv; ++argv)
     95 		if (!freopen(*argv, "r", stdin)) {
     96 			(void)fprintf(stderr,
     97 			    "fold: %s: %s\n", *argv, strerror(errno));
     98 			exit(1);
     99 		} else
    100 			fold(width);
    101 	exit(0);
    102 }
    103 
    104 fold(width)
    105 	register int width;
    106 {
    107 	register int ch, col, new;
    108 
    109 	for (col = 0;;) {
    110 		switch (ch = getchar()) {
    111 		case EOF:
    112 			return;
    113 		case '\b':
    114 			new = col ? col - 1 : 0;
    115 			break;
    116 		case '\n':
    117 		case '\r':
    118 			new = 0;
    119 			break;
    120 		case '\t':
    121 			new = (col + 8) & ~7;
    122 			break;
    123 		default:
    124 			new = col + 1;
    125 			break;
    126 		}
    127 
    128 		if (new > width) {
    129 			putchar('\n');
    130 			col = 0;
    131 		}
    132 		putchar(ch);
    133 
    134 		switch (ch) {
    135 		case '\b':
    136 			if (col > 0)
    137 				--col;
    138 			break;
    139 		case '\n':
    140 		case '\r':
    141 			col = 0;
    142 			break;
    143 		case '\t':
    144 			col += 8;
    145 			col &= ~7;
    146 			break;
    147 		default:
    148 			++col;
    149 			break;
    150 		}
    151 	}
    152 }
    153