scm_take_locale_stringn using realloc

[Kevin Ryde]

In scm_take_locale_stringn, how about using realloc to add a null
terminator to the block being acquired?  That should usually be better
than the current code doing malloc+copy+free.

Something like the following,


SCM
scm_take_locale_stringn (char *str, size_t len)
{
  SCM buf, res;

  if (len == (size_t)-1)
    len = strlen (str);
  else
    {
      /* Ensure STR is null terminated.  A realloc for 1 extra byte should
         often be satisfied from the alignment padding after the block, with
         no actual data movement.  */
      str = scm_realloc (str, len+1);
      str[len] = '\0';
    }

  buf = scm_double_cell (STRINGBUF_TAG, (scm_t_bits) str,
                         (scm_t_bits) len, (scm_t_bits) 0);
  res = scm_double_cell (STRING_TAG,
                         SCM_UNPACK (buf),
                         (scm_t_bits) 0, (scm_t_bits) len);
  scm_gc_register_collectable_memory (str, len+1, "string");
  return res;
}

SCM
scm_take_locale_string (char *str)
{
  return scm_take_locale_stringn (str, -1);
}