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 && line[len-1] == '\n') {
  16                 if (len == 1)
  17                         return 0;
  18                 do {
  19                         unsigned char c = line[len-2];
  20                         if (!isspace(c))
  21                                 break;
  22                         line[len-2] = '\n';
  23                         len--;
  24                         line[len] = 0;
  25                 } while (len > 1);
  26                 return 0;
  27         }
  28         return 1;
  29 }
  30
  31 int main(int argc, char **argv)
  32 {
  33         int empties = -1;
  34         int incomplete = 0;
  35         char line[1024];
  36
  37         while (fgets(line, sizeof(line), stdin)) {
  38                 incomplete = cleanup(line);
  39
  40                 /* Not just an empty line? */
  41                 if (line[0] != '\n') {
  42                         if (empties > 0)
  43                                 putchar('\n');
  44                         empties = 0;
  45                         fputs(line, stdout);
  46                         continue;
  47                 }
  48                 if (empties < 0)
  49                         continue;
  50                 empties++;
  51         }
  52         if (incomplete)
  53                 putchar('\n');
  54         return 0;
  55 }