--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/graal/com.oracle.truffle.api/src/com/oracle/truffle/api/source/BytesDecoder.java	Mon Sep 08 22:21:21 2014 +0100
@@ -0,0 +1,66 @@
+/*
+ * Copyright (c) 2014, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.  Oracle designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Oracle in the LICENSE file that accompanied this code.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+package com.oracle.truffle.api.source;
+
+import java.nio.charset.*;
+import java.util.*;
+
+/**
+ * For a language where strings do not map into Java strings, provides utilities to find line
+ * endings and to decode raw bytes into an approximate representation for tools to display.
+ * <p>
+ * See {@link Source#fromBytes}.
+ */
+public interface BytesDecoder {
+
+    String decode(byte[] bytes, int byteIndex, int length);
+
+    void decodeLines(byte[] bytes, int byteIndex, int length, LineMarker lineMarker);
+
+    public interface LineMarker {
+
+        void markLine(int index);
+
+    }
+
+    public static class UTF8BytesDecoder implements BytesDecoder {
+
+        @Override
+        public String decode(byte[] bytes, int byteIndex, int length) {
+            return new String(Arrays.copyOfRange(bytes, byteIndex, byteIndex + length), StandardCharsets.UTF_8);
+        }
+
+        @Override
+        public void decodeLines(byte[] bytes, int byteIndex, int length, LineMarker lineMarker) {
+            for (int n = byteIndex; n < byteIndex + length; n++) {
+                if (bytes[n] == '\n') {
+                    lineMarker.markLine(n + 1);
+                }
+            }
+        }
+
+    }
+
+}