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.  Return true if it is an incomplete line.
  10  */
  11 static int 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                 return 0;
  25         }
  26         return 1;
  27 }
  28
  29 int main(int argc, char **argv)
  30 {
  31         int empties = -1;
  32         int incomplete = 0;
  33         char line[1024];
  34
  35         while (fgets(line, sizeof(line), stdin)) {
  36                 incomplete = cleanup(line);
  37
  38                 /* Not just an empty line? */
  39                 if (line[0] != '\n') {
  40                         if (empties > 0)
  41                                 putchar('\n');
  42                         empties = 0;
  43                         fputs(line, stdout);
  44                         continue;
  45                 }
  46                 if (empties < 0)
  47                         continue;
  48                 empties++;
  49         }
  50         if (incomplete)
  51                 putchar('\n');
  52         return 0;
  53 }