Home | History | Annotate | Line # | Download | only in expand 
      1 /*	$NetBSD: expand.c,v 1.14 2016/09/05 00:40:28 sevan Exp $	*/
      2 
      3 /*
      4  * Copyright (c) 1980, 1993
      5  *	The Regents of the University of California.  All rights reserved.
      6  *
      7  * Redistribution and use in source and binary forms, with or without
      8  * modification, are permitted provided that the following conditions
      9  * are met:
     10  * 1. Redistributions of source code must retain the above copyright
     11  *    notice, this list of conditions and the following disclaimer.
     12  * 2. Redistributions in binary form must reproduce the above copyright
     13  *    notice, this list of conditions and the following disclaimer in the
     14  *    documentation and/or other materials provided with the distribution.
     15  * 3. Neither the name of the University nor the names of its contributors
     16  *    may be used to endorse or promote products derived from this software
     17  *    without specific prior written permission.
     18  *
     19  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     29  * SUCH DAMAGE.
     30  */
     31 
     32 #include <sys/cdefs.h>
     33 #ifndef lint
     34 __COPYRIGHT("@(#) Copyright (c) 1980, 1993\
     35  The Regents of the University of California.  All rights reserved.");
     36 #endif /* not lint */
     37 
     38 #ifndef lint
     39 #if 0
     40 static char sccsid[] = "@(#)expand.c	8.1 (Berkeley) 6/9/93";
     41 #endif
     42 __RCSID("$NetBSD: expand.c,v 1.14 2016/09/05 00:40:28 sevan Exp $");
     43 #endif /* not lint */
     44 
     45 #include <stdio.h>
     46 #include <stdlib.h>
     47 #include <ctype.h>
     48 #include <unistd.h>
     49 #include <err.h>
     50 
     51 /*
     52  * expand - expand tabs to equivalent spaces
     53  */
     54 size_t	nstops;
     55 size_t	tabstops[100];
     56 
     57 static	void	getstops(const char *);
     58 static	void	usage(void) __dead;
     59 
     60 int
     61 main(int argc, char *argv[])
     62 {
     63 	int c;
     64 	size_t n, column;
     65 
     66 	setprogname(argv[0]);
     67 
     68 	/* handle obsolete syntax */
     69 	while (argc > 1 &&
     70 	    argv[1][0] == '-' && isdigit((unsigned char)argv[1][1])) {
     71 		getstops(&argv[1][1]);
     72 		argc--; argv++;
     73 	}
     74 
     75 	while ((c = getopt (argc, argv, "t:")) != -1) {
     76 		switch (c) {
     77 		case 't':
     78 			getstops(optarg);
     79 			break;
     80 		case '?':
     81 		default:
     82 			usage();
     83 			/* NOTREACHED */
     84 		}
     85 	}
     86 	argc -= optind;
     87 	argv += optind;
     88 
     89 	do {
     90 		if (argc > 0) {
     91 			if (freopen(argv[0], "r", stdin) == NULL)
     92 				err(EXIT_FAILURE, "Cannot open `%s'", argv[0]);
     93 			argc--, argv++;
     94 		}
     95 		column = 0;
     96 		while ((c = getchar()) != EOF) {
     97 			switch (c) {
     98 			case '\t':
     99 				if (nstops == 0) {
    100 					do {
    101 						putchar(' ');
    102 						column++;
    103 					} while (column & 07);
    104 					continue;
    105 				}
    106 				if (nstops == 1) {
    107 					do {
    108 						putchar(' ');
    109 						column++;
    110 					} while (((column - 1) % tabstops[0])
    111 					    != (tabstops[0] - 1));
    112 					continue;
    113 				}
    114 				for (n = 0; n < nstops; n++)
    115 					if (tabstops[n] > column)
    116 						break;
    117 				if (n == nstops) {
    118 					putchar(' ');
    119 					column++;
    120 					continue;
    121 				}
    122 				while (column < tabstops[n]) {
    123 					putchar(' ');
    124 					column++;
    125 				}
    126 				continue;
    127 
    128 			case '\b':
    129 				if (column)
    130 					column--;
    131 				putchar('\b');
    132 				continue;
    133 
    134 			default:
    135 				putchar(c);
    136 				column++;
    137 				continue;
    138 
    139 			case '\n':
    140 				putchar(c);
    141 				column = 0;
    142 				continue;
    143 			}
    144 		}
    145 	} while (argc > 0);
    146 	return EXIT_SUCCESS;
    147 }
    148 
    149 static void
    150 getstops(const char *spec)
    151 {
    152 	int i;
    153 	const char *cp = spec;
    154 
    155 	nstops = 0;
    156 	for (;;) {
    157 		i = 0;
    158 		while (*cp >= '0' && *cp <= '9')
    159 			i = i * 10 + *cp++ - '0';
    160 		if (i <= 0 || i > 256)
    161 			errx(EXIT_FAILURE, "Too large tab stop spec `%d'", i);
    162 		if (nstops > 0 && (size_t)i <= tabstops[nstops-1])
    163 			errx(EXIT_FAILURE, "Out of order tabstop spec `%d'", i);
    164 		if (nstops == sizeof(tabstops) / sizeof(tabstops[0]) - 1)
    165 			errx(EXIT_FAILURE, "Too many tabstops");
    166 		tabstops[nstops++] = i;
    167 		if (*cp == '\0')
    168 			break;
    169 		if (*cp != ',' && *cp != ' ')
    170 			errx(EXIT_FAILURE, "Illegal tab stop spec `%s'", spec);
    171 		cp++;
    172 	}
    173 }
    174 
    175 static void
    176 usage(void)
    177 {
    178 
    179 	(void)fprintf(stderr, "Usage: %s [-t tablist] [file ...]\n",
    180 	    getprogname());
    181 	exit(EXIT_FAILURE);
    182 }
    183