builtin-stripspace.c

   1 #include "builtin.h"
   2
   3 /*
   4  * Remove empty lines from the beginning and end.
   5  *
   6  * Turn multiple consecutive empty lines into just one
   7  * empty line.  Return true if it is an incomplete line.
   8  */
   9 static int cleanup(char *line)
  10 {
  11         int len = strlen(line);
  12
  13         if (len && line[len-1] == '\n') {
  14                 if (len == 1)
  15                         return 0;
  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 static void stripspace(FILE *in, FILE *out)
  30 {
  31         int empties = -1;
  32         int incomplete = 0;
  33         char line[1024];
  34
  35         while (fgets(line, sizeof(line), in)) {
  36                 incomplete = cleanup(line);
  37
  38                 /* Not just an empty line? */
  39                 if (line[0] != '\n') {
  40                         if (empties > 0)
  41                                 fputc('\n', out);
  42                         empties = 0;
  43                         fputs(line, out);
  44                         continue;
  45                 }
  46                 if (empties < 0)
  47                         continue;
  48                 empties++;
  49         }
  50         if (incomplete)
  51                 fputc('\n', out);
  52 }
  53
  54 int cmd_stripspace(int argc, const char **argv, const char *prefix)
  55 {
  56         stripspace(stdin, stdout);
  57         return 0;
  58 }