commands/expand/expand.c

   1 /*  expand - expand tabs to spaces      Author: Terrence W. Holm */
   2
   3 /*  Usage:  expand  [ -tab1,tab2,tab3,... ]  [ file ... ]  */
   4
   5 #include <stddef.h>
   6 #include <string.h>
   7 #include <stdlib.h>
   8 #include <stdio.h>
   9
  10 #define MAX_TABS 32
  11
  12 int column = 0;                 /* Current column, retained between files  */
  13
  14 int main(int argc, char **argv);
  15 void Expand(FILE *f, int tab_index, int tabs []);
  16
  17 int main(argc, argv)
  18 int argc;
  19 char *argv[];
  20 {
  21   int tabs[MAX_TABS];
  22   int tab_index = 0;            /* Default one tab   */
  23   int i;
  24   FILE *f;
  25
  26   tabs[0] = 8;                  /* Default tab stop  */
  27
  28   if (argc > 1 && argv[1][0] == '-') {
  29         char *p = argv[1];
  30         int last_tab_stop = 0;
  31
  32         for (tab_index = 0; tab_index < MAX_TABS; ++tab_index) {
  33                 if ((tabs[tab_index] = atoi(p + 1)) <= last_tab_stop) {
  34                         fprintf(stderr, "Bad tab stop spec\n");
  35                         exit(1);
  36                 }
  37                 last_tab_stop = tabs[tab_index];
  38
  39                 if ((p = strchr(p + 1, ',')) == NULL) break;
  40         }
  41
  42         --argc;
  43         ++argv;
  44   }
  45   if (argc == 1)
  46         Expand(stdin, tab_index, tabs);
  47   else
  48         for (i = 1; i < argc; ++i) {
  49                 if ((f = fopen(argv[i], "r")) == NULL) {
  50                         perror(argv[i]);
  51                         exit(1);
  52                 }
  53                 Expand(f, tab_index, tabs);
  54                 fclose(f);
  55         }
  56
  57   return(0);
  58 }
  59
  60
  61 void Expand(f, tab_index, tabs)
  62 FILE *f;
  63 int tab_index;
  64 int tabs[];
  65 {
  66   int next;
  67   int c;
  68   int i;
  69
  70   while ((c = getc(f)) != EOF) {
  71         if (c == '\t') {
  72                 if (tab_index == 0)
  73                         next = (column / tabs[0] + 1) * tabs[0];
  74                 else {
  75                         for (i = 0; i <= tab_index && tabs[i] <= column; ++i);
  76
  77                         if (i > tab_index)
  78                                 next = column + 1;
  79                         else
  80                                 next = tabs[i];
  81                 }
  82
  83                 do {
  84                         ++column;
  85                         putchar(' ');
  86                 } while (column < next);
  87
  88                 continue;
  89         }
  90         if (c == '\b')
  91                 column = column > 0 ? column - 1 : 0;
  92         else if (c == '\n' || c == '\r')
  93                 column = 0;
  94         else
  95                 ++column;
  96
  97         putchar(c);
  98   }
  99 }