src/Pure/System/utf8.scala

   val charset: Charset = Charset.forName(charset_name)
   def codec(): Codec = Codec(charset)
 
   def bytes(s: String): Array[Byte] = s.getBytes(charset)
 
-  def bytes_length(s: String): Int =
-    (0 /: Codepoint.iterator(s)) {
-      case (n, i) =>
-        if (i < 0x80) n + 1
-        else if (i < 0x800) n + 2
-        else if (i < 0x10000) n + 3
-        else n + 4
-    }
-
-  object Length extends Line.Length { def apply(s: String): Int = bytes_length(s) }
+  object Length extends Codepoint.Length
+  {
+    override def codepoint_length(c: Int): Int =
+      if (c < 0x80) 1
+      else if (c < 0x800) 2
+      else if (c < 0x10000) 3
+      else 4
+  }
 
 
   /* permissive UTF-8 decoding */
 
   // see also http://en.wikipedia.org/wiki/UTF-8#Description

   {
     require(0 <= start && start <= end && end <= buffer.length)
     new Decode_Chars(decode, buffer, start, end)
   }
 }
-