BSD 4_1_snap release

[unix-history] / usr / src / cmd / expand.c

static char *sccsid = "@(#)expand.c     4.2 (Berkeley) 2/7/81";
#include <stdio.h>
/*
* expand - expand tabs to equivalent spaces
*/
char    obuf[BUFSIZ];
int     nstops;
int     tabstops[100];

main(argc, argv)
       int argc;
       char *argv[];
{
       register int c, column;
       register int n;

       setbuf(stdout, obuf);
       argc--, argv++;
       do {
               while (argc > 0 && argv[0][0] == '-') {
                       getstops(argv[0]);
                       argc--, argv++;
               }
               if (argc > 0) {
                       if (freopen(argv[0], "r", stdin) == NULL) {
                               perror(argv[0]);
                               exit(1);
                       }
                       argc--, argv++;
               }
               column = 0;
               for (;;) {
                       c = getc(stdin);
                       if (c == -1)
                               break;
                       switch (c) {

                       case '\t':
                               if (nstops == 0) {
                                       do {
                                               putchar(' ');
                                               column++;
                                       } while (column & 07);
                                       continue;
                               }
                               if (nstops == 1) {
                                       do {
                                               putchar(' ');
                                               column++;
                                       } while (((column - 1) % tabstops[0]) != (tabstops[0] - 1));
                                       continue;
                               }
                               for (n = 0; n < nstops; n++)
                                       if (tabstops[n] > column)
                                               break;
                               if (n == nstops) {
                                       putchar(' ');
                                       column++;
                                       continue;
                               }
                               while (column < tabstops[n]) {
                                       putchar(' ');
                                       column++;
                               }
                               continue;

                       case '\b':
                               if (column)
                                       column--;
                               putchar('\b');
                               continue;

                       default:
                               putchar(c);
                               column++;
                               continue;

                       case '\n':
                               putchar(c);
                               column = 0;
                               continue;
                       }
               }
       } while (argc > 0);
       exit(0);
}

getstops(cp)
       register char *cp;
{
       register int i;

       nstops = 0;
       cp++;
       for (;;) {
               i = 0;
               while (*cp >= '0' && *cp <= '9')
                       i = i * 10 + *cp++ - '0';
               if (i <= 0 || i > 256) {
bad:
                       fprintf(stderr, "Bad tab stop spec\n");
                       exit(1);
               }
               if (nstops > 0 && i <= tabstops[nstops-1])
                       goto bad;
               tabstops[nstops++] = i;
               if (*cp == 0)
                       break;
               if (*cp++ != ',')
                       goto bad;
       }
}