builtin-stripspace.c

   1 #include "builtin.h"
   2 #include "cache.h"
   3
   4 /*
   5  * Remove trailing spaces from a line.
   6  *
   7  * If the line ends with newline, it will be removed too.
   8  * Returns the new length of the string.
   9  */
  10 static int cleanup(char *line, int len)
  11 {
  12         if (len) {
  13                 if (line[len - 1] == '\n')
  14                         len--;
  15
  16                 while (len) {
  17                         unsigned char c = line[len - 1];
  18                         if (!isspace(c))
  19                                 break;
  20                         len--;
  21                 }
  22                 line[len] = 0;
  23         }
  24         return len;
  25 }
  26
  27 /*
  28  * Remove empty lines from the beginning and end
  29  * and also trailing spaces from every line.
  30  *
  31  * Turn multiple consecutive empty lines between paragraphs
  32  * into just one empty line.
  33  *
  34  * If the input has only empty lines and spaces,
  35  * no output will be produced.
  36  *
  37  * Enable skip_comments to skip every line starting with "#".
  38  */
  39 void stripspace(FILE *in, FILE *out, int skip_comments)
  40 {
  41         int empties = -1;
  42         int alloc = 1024;
  43         char *line = xmalloc(alloc);
  44
  45         while (fgets(line, alloc, in)) {
  46                 int len = strlen(line);
  47
  48                 while (len == alloc - 1 && line[len - 1] != '\n') {
  49                         alloc = alloc_nr(alloc);
  50                         line = xrealloc(line, alloc);
  51                         fgets(line + len, alloc - len, in);
  52                         len += strlen(line + len);
  53                 }
  54
  55                 if (skip_comments && line[0] == '#')
  56                         continue;
  57                 len = cleanup(line, len);
  58
  59                 /* Not just an empty line? */
  60                 if (len) {
  61                         if (empties > 0)
  62                                 fputc('\n', out);
  63                         empties = 0;
  64                         fputs(line, out);
  65                         fputc('\n', out);
  66                         continue;
  67                 }
  68                 if (empties < 0)
  69                         continue;
  70                 empties++;
  71         }
  72         free(line);
  73 }
  74
  75 int cmd_stripspace(int argc, const char **argv, const char *prefix)
  76 {
  77         stripspace(stdin, stdout, 0);
  78         return 0;
  79 }