source: trunk/minix/commands/simple/expand.c@ 10

/*  expand - expand tabs to spaces      Author: Terrence W. Holm */

/*  Usage:  expand  [ -tab1,tab2,tab3,... ]  [ file ... ]  */

#include <stddef.h>
#include <string.h>
#include <stdlib.h>
#include <stdio.h>

#define MAX_TABS 32

int column = 0;                 /* Current column, retained between files  */

_PROTOTYPE(int main, (int argc, char **argv));
_PROTOTYPE(void Expand, (FILE *f, int tab_index, int tabs []));

int main(argc, argv)
int argc;
char *argv[];
{
  int tabs[MAX_TABS];
  int tab_index = 0;            /* Default one tab   */
  int i;
  FILE *f;

  tabs[0] = 8;                  /* Default tab stop  */

  if (argc > 1 && argv[1][0] == '-') {
        char *p = argv[1];
        int last_tab_stop = 0;

        for (tab_index = 0; tab_index < MAX_TABS; ++tab_index) {
                if ((tabs[tab_index] = atoi(p + 1)) <= last_tab_stop) {
                        fprintf(stderr, "Bad tab stop spec\n");
                        exit(1);
                }
                last_tab_stop = tabs[tab_index];

                if ((p = strchr(p + 1, ',')) == NULL) break;
        }

        --argc;
        ++argv;
  }
  if (argc == 1)
        Expand(stdin, tab_index, tabs);
  else
        for (i = 1; i < argc; ++i) {
                if ((f = fopen(argv[i], "r")) == NULL) {
                        perror(argv[i]);
                        exit(1);
                }
                Expand(f, tab_index, tabs);
                fclose(f);
        }

  return(0);
}


void Expand(f, tab_index, tabs)
FILE *f;
int tab_index;
int tabs[];
{
  int next;
  int c;
  int i;

  while ((c = getc(f)) != EOF) {
        if (c == '\t') {
                if (tab_index == 0)
                        next = (column / tabs[0] + 1) * tabs[0];
                else {
                        for (i = 0; i <= tab_index && tabs[i] <= column; ++i);

                        if (i > tab_index)
                                next = column + 1;
                        else
                                next = tabs[i];
                }

                do {
                        ++column;
                        putchar(' ');
                } while (column < next);

                continue;
        }
        if (c == '\b')
                column = column > 0 ? column - 1 : 0;
        else if (c == '\n' || c == '\r')
                column = 0;
        else
                ++column;

        putchar(c);
  }
}