(Fget_byte): Fix and make it faster for unibyte target.

src/ChangeLog

+2008-11-10  Kenichi Handa  <handa@m17n.org>
+
+	* character.c (Fget_byte): Fix and make it faster for unibyte
+	target.
+
 2008-11-08  Chong Yidong  <cyd@stupidchicken.com>
 	* dired.c (file_name_completion): If completion_ignore_case is

src/character.c

@@ -1058,6 +1058,8 @@ character is not ASCII nor 8-bit character, an error is signalled.  */)
 	  pos = XFASTINT (position);
 	  p = CHAR_POS_ADDR (pos);
 	}
+      if (NILP (current_buffer->enable_multibyte_characters))
+	return make_number (*p);
     }
   else
     {
@@ -1074,6 +1076,8 @@ character is not ASCII nor 8-bit character, an error is signalled.  */)
 	  pos = XFASTINT (position);
 	  p = SDATA (string) + string_char_to_byte (string, pos);
 	}
+      if (! STRING_MULTIBYTE (string))
+	return make_number (*p);
     }
   c = STRING_CHAR (p, 0);
   if (CHAR_BYTE8_P (c))