text/flat: FlatText::char_to_byte_index shortcut length_of_char_at if possible

Signed-off-by: Jean Privat <jean@pryen.org>

diff --git a/lib/core/text/flat.nit b/lib/core/text/flat.nit
index 200fdcf..2615304 100644 (file)
--- a/lib/core/text/flat.nit
+++ b/lib/core/text/flat.nit
@@ -55,7 +55,11 @@ redef class FlatText
                var its = _items
 
                if dpos == 1 then
-                       b += _items.length_of_char_at(b)
+                       if its[b] & 0x80u8 == 0x00u8 then
+                               b += 1
+                       else
+                               b += its.length_of_char_at(b)
+                       end
                        _bytepos = b
                        _position = index
                        return b