builtin-stripspace.c

   1 #include <stdio.h>
   2 #include <string.h>
   3 #include <ctype.h>
   4 #include "builtin.h"
   5
   6 /*
   7  * Remove empty lines from the beginning and end.
   8  *
   9  * Turn multiple consecutive empty lines into just one
  10  * empty line.  Return true if it is an incomplete line.
  11  */
  12 static int cleanup(char *line)
  13 {
  14         int len = strlen(line);
  15
  16         if (len && line[len-1] == '\n') {
  17                 if (len == 1)
  18                         return 0;
  19                 do {
  20                         unsigned char c = line[len-2];
  21                         if (!isspace(c))
  22                                 break;
  23                         line[len-2] = '\n';
  24                         len--;
  25                         line[len] = 0;
  26                 } while (len > 1);
  27                 return 0;
  28         }
  29         return 1;
  30 }
  31
  32 void stripspace(FILE *in, FILE *out)
  33 {
  34         int empties = -1;
  35         int incomplete = 0;
  36         char line[1024];
  37
  38         while (fgets(line, sizeof(line), in)) {
  39                 incomplete = cleanup(line);
  40
  41                 /* Not just an empty line? */
  42                 if (line[0] != '\n') {
  43                         if (empties > 0)
  44                                 fputc('\n', out);
  45                         empties = 0;
  46                         fputs(line, out);
  47                         continue;
  48                 }
  49                 if (empties < 0)
  50                         continue;
  51                 empties++;
  52         }
  53         if (incomplete)
  54                 fputc('\n', out);
  55 }
  56
  57 int cmd_stripspace(int argc, const char **argv, char **envp)
  58 {
  59         stripspace(stdin, stdout);
  60         return 0;
  61 }