builtin-stripspace.c

   1 #include "builtin.h"
   2 #include "cache.h"
   3
   4 /*
   5  * Returns the length of a line, without trailing spaces.
   6  *
   7  * If the line ends with newline, it will be removed too.
   8  */
   9 static size_t cleanup(char *line, size_t len)
  10 {
  11         while (len) {
  12                 unsigned char c = line[len - 1];
  13                 if (!isspace(c))
  14                         break;
  15                 len--;
  16         }
  17
  18         return len;
  19 }
  20
  21 /*
  22  * Remove empty lines from the beginning and end
  23  * and also trailing spaces from every line.
  24  *
  25  * Note that the buffer will not be NUL-terminated.
  26  *
  27  * Turn multiple consecutive empty lines between paragraphs
  28  * into just one empty line.
  29  *
  30  * If the input has only empty lines and spaces,
  31  * no output will be produced.
  32  *
  33  * If last line does not have a newline at the end, one is added.
  34  *
  35  * Enable skip_comments to skip every line starting with "#".
  36  */
  37 void stripspace(struct strbuf *sb, int skip_comments)
  38 {
  39         int empties = 0;
  40         size_t i, j, len, newlen;
  41         char *eol;
  42
  43         /* We may have to add a newline. */
  44         strbuf_grow(sb, 1);
  45
  46         for (i = j = 0; i < sb->len; i += len, j += newlen) {
  47                 eol = memchr(sb->buf + i, '\n', sb->len - i);
  48                 len = eol ? eol - (sb->buf + i) + 1 : sb->len - i;
  49
  50                 if (skip_comments && len && sb->buf[i] == '#') {
  51                         newlen = 0;
  52                         continue;
  53                 }
  54                 newlen = cleanup(sb->buf + i, len);
  55
  56                 /* Not just an empty line? */
  57                 if (newlen) {
  58                         if (empties > 0 && j > 0)
  59                                 sb->buf[j++] = '\n';
  60                         empties = 0;
  61                         memmove(sb->buf + j, sb->buf + i, newlen);
  62                         sb->buf[newlen + j++] = '\n';
  63                 } else {
  64                         empties++;
  65                 }
  66         }
  67
  68         strbuf_setlen(sb, j);
  69 }
  70
  71 int cmd_stripspace(int argc, const char **argv, const char *prefix)
  72 {
  73         struct strbuf buf = STRBUF_INIT;
  74         int strip_comments = 0;
  75
  76         if (argc > 1 && (!strcmp(argv[1], "-s") ||
  77                                 !strcmp(argv[1], "--strip-comments")))
  78                 strip_comments = 1;
  79
  80         if (strbuf_read(&buf, 0, 1024) < 0)
  81                 die_errno("could not read the input");
  82
  83         stripspace(&buf, strip_comments);
  84
  85         write_or_die(1, buf.buf, buf.len);
  86         strbuf_release(&buf);
  87         return 0;
  88 }