5071718: (bf) Add ByteBuffer.slice(int offset, int length)

Reviewed-by: alanb, bchristi, darcy, rriggs

src/java.base/share/classes/java/nio/ByteBufferAs-X-Buffer.java.template

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2000, 2016, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2000, 2019, 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
@@ -27,9 +27,9 @@
 
 package java.nio;
 
+import java.util.Objects;
 import jdk.internal.misc.Unsafe;
 
-
 class ByteBufferAs$Type$Buffer$RW$$BO$                  // package-private
     extends {#if[ro]?ByteBufferAs}$Type$Buffer{#if[ro]?$BO$}
 {
@@ -85,6 +85,18 @@ class ByteBufferAs$Type$Buffer$RW$$BO$                  // package-private
         return new ByteBufferAs$Type$Buffer$RW$$BO$(bb, -1, 0, rem, rem, addr);
     }
 
+    @Override
+    public $Type$Buffer slice(int index, int length) {
+        Objects.checkIndex(index, limit() + 1);
+        Objects.checkIndex(length, limit() - index + 1);
+        return new ByteBufferAs$Type$Buffer$RW$$BO$(bb,
+                                                    -1,
+                                                    0,
+                                                    length,
+                                                    length,
+                                                    byteOffset(index));
+    }
+
     public $Type$Buffer duplicate() {
         return new ByteBufferAs$Type$Buffer$RW$$BO$(bb,
                                                     this.markValue(),