stripspace.c

   1 #include <stdio.h>
   2 #include <string.h>
   3 #include <ctype.h>
   4
   5 /*
   6  * Remove empty lines from the beginning and end.
   7  *
   8  * Turn multiple consecutive empty lines into just one
   9  * empty line.
  10  */
  11 static void cleanup(char *line)
  12 {
  13         int len = strlen(line);
  14
  15         if (len > 1 && line[len-1] == '\n') {
  16                 do {
  17                         unsigned char c = line[len-2];
  18                         if (!isspace(c))
  19                                 break;
  20                         line[len-2] = '\n';
  21                         len--;
  22                         line[len] = 0;
  23                 } while (len > 1);
  24         }
  25 }
  26
  27 int main(int argc, char **argv)
  28 {
  29         int empties = -1;
  30         char line[1024];
  31
  32         while (fgets(line, sizeof(line), stdin)) {
  33                 cleanup(line);
  34
  35                 /* Not just an empty line? */
  36                 if (line[0] != '\n') {
  37                         if (empties > 0)
  38                                 putchar('\n');
  39                         empties = 0;
  40                         fputs(line, stdout);
  41                         continue;
  42                 }
  43                 if (empties < 0)
  44                         continue;
  45                 empties++;
  46         }
  47         return 0;
  48 }