Fixes a bug in UnsafeBuffer.wrap with raw memory address.

The wrapAdjustment isn't reset when calling with a raw
memory address.

The consequence is that you access memory at the wrong
position because the wrapAdjustment still has the value
of an earlier wrap.

Author: pveentjer

agrona/src/main/java/org/agrona/concurrent/UnsafeBuffer.java

@@ -321,6 +321,7 @@ public void wrap(final long address, final int length)
         addressOffset = address;
         byteArray = null;
         byteBuffer = null;
+        wrapAdjustment = 0;
     }
 
     /**

agrona/src/test/java/org/agrona/concurrent/UnsafeBufferTest.java

@@ -15,6 +15,7 @@
  */
 package org.agrona.concurrent;
 
+import org.agrona.BufferUtil;
 import org.agrona.DirectBuffer;
 import org.agrona.ExpandableArrayBuffer;
 import org.agrona.ExpandableDirectByteBuffer;
@@ -325,4 +326,22 @@ private static List<DirectBuffer> directBuffers()
             new UnsafeBuffer(ByteBuffer.allocate(64)),
             mockBuffer);
     }
+
+    @Test
+    public void wrapForRawMemoryAddressShouldResetWrapAdjustment()
+    {
+        final UnsafeBuffer buffer = new UnsafeBuffer();
+
+        // first we set a non zero wrap adjustment
+        final byte[] array = new byte[100];
+        buffer.wrap(array, 25, 50);
+
+        // now a wrap is done with a raw memory address which should reset the wrap adjustment.
+        final ByteBuffer directBuffer = ByteBuffer.allocateDirect(64);
+        final long address = BufferUtil.address(directBuffer);
+        buffer.wrap(address, 64);
+
+        assertEquals(0, buffer.wrapAdjustment());
+    }
+
 }