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expand.c revision 1.1 
      1 /*
      2  * Copyright (c) 1980 The Regents of the University of California.
      3  * 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 char copyright[] =
     36 "@(#) Copyright (c) 1980 The Regents of the University of California.\n\
     37  All rights reserved.\n";
     38 #endif /* not lint */
     39 
     40 #ifndef lint
     41 static char sccsid[] = "@(#)expand.c	5.3 (Berkeley) 6/1/90";
     42 #endif /* not lint */
     43 
     44 #include <stdio.h>
     45 /*
     46  * expand - expand tabs to equivalent spaces
     47  */
     48 int	nstops;
     49 int	tabstops[100];
     50 
     51 main(argc, argv)
     52 	int argc;
     53 	char *argv[];
     54 {
     55 	register int c, column;
     56 	register int n;
     57 
     58 	argc--, argv++;
     59 	do {
     60 		while (argc > 0 && argv[0][0] == '-') {
     61 			getstops(argv[0]);
     62 			argc--, argv++;
     63 		}
     64 		if (argc > 0) {
     65 			if (freopen(argv[0], "r", stdin) == NULL) {
     66 				perror(argv[0]);
     67 				exit(1);
     68 			}
     69 			argc--, argv++;
     70 		}
     71 		column = 0;
     72 		for (;;) {
     73 			c = getc(stdin);
     74 			if (c == -1)
     75 				break;
     76 			switch (c) {
     77 
     78 			case '\t':
     79 				if (nstops == 0) {
     80 					do {
     81 						putchar(' ');
     82 						column++;
     83 					} while (column & 07);
     84 					continue;
     85 				}
     86 				if (nstops == 1) {
     87 					do {
     88 						putchar(' ');
     89 						column++;
     90 					} while (((column - 1) % tabstops[0]) != (tabstops[0] - 1));
     91 					continue;
     92 				}
     93 				for (n = 0; n < nstops; n++)
     94 					if (tabstops[n] > column)
     95 						break;
     96 				if (n == nstops) {
     97 					putchar(' ');
     98 					column++;
     99 					continue;
    100 				}
    101 				while (column < tabstops[n]) {
    102 					putchar(' ');
    103 					column++;
    104 				}
    105 				continue;
    106 
    107 			case '\b':
    108 				if (column)
    109 					column--;
    110 				putchar('\b');
    111 				continue;
    112 
    113 			default:
    114 				putchar(c);
    115 				column++;
    116 				continue;
    117 
    118 			case '\n':
    119 				putchar(c);
    120 				column = 0;
    121 				continue;
    122 			}
    123 		}
    124 	} while (argc > 0);
    125 	exit(0);
    126 }
    127 
    128 getstops(cp)
    129 	register char *cp;
    130 {
    131 	register int i;
    132 
    133 	nstops = 0;
    134 	cp++;
    135 	for (;;) {
    136 		i = 0;
    137 		while (*cp >= '0' && *cp <= '9')
    138 			i = i * 10 + *cp++ - '0';
    139 		if (i <= 0 || i > 256) {
    140 bad:
    141 			fprintf(stderr, "Bad tab stop spec\n");
    142 			exit(1);
    143 		}
    144 		if (nstops > 0 && i <= tabstops[nstops-1])
    145 			goto bad;
    146 		tabstops[nstops++] = i;
    147 		if (*cp == 0)
    148 			break;
    149 		if (*cp++ != ',')
    150 			goto bad;
    151 	}
    152 }
    153