Importing upstream Jetty jetty-9.2.1.v20140609

[gigi.git] / lib / jetty / org / eclipse / jetty / util / MemoryUtils.java

diff --git a/lib/jetty/org/eclipse/jetty/util/MemoryUtils.java b/lib/jetty/org/eclipse/jetty/util/MemoryUtils.java
new file mode 100644 (file)
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+++ b/lib/jetty/org/eclipse/jetty/util/MemoryUtils.java
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+//
+//  ========================================================================
+//  Copyright (c) 1995-2014 Mort Bay Consulting Pty. Ltd.
+//  ------------------------------------------------------------------------
+//  All rights reserved. This program and the accompanying materials
+//  are made available under the terms of the Eclipse Public License v1.0
+//  and Apache License v2.0 which accompanies this distribution.
+//
+//      The Eclipse Public License is available at
+//      http://www.eclipse.org/legal/epl-v10.html
+//
+//      The Apache License v2.0 is available at
+//      http://www.opensource.org/licenses/apache2.0.php
+//
+//  You may elect to redistribute this code under either of these licenses.
+//  ========================================================================
+//
+
+package org.eclipse.jetty.util;
+
+import java.security.AccessController;
+import java.security.PrivilegedAction;
+
+/**
+ * {@link MemoryUtils} provides an abstraction over memory properties and operations.
+ * <p />
+ */
+public class MemoryUtils
+{
+    private static final int cacheLineBytes;
+    static
+    {
+        final int defaultValue = 64;
+        int value = defaultValue;
+        try
+        {
+            value = Integer.parseInt(AccessController.doPrivileged(new PrivilegedAction<String>()
+            {
+                @Override
+                public String run()
+                {
+                    return System.getProperty("org.eclipse.jetty.util.cacheLineBytes", String.valueOf(defaultValue));
+                }
+            }));
+        }
+        catch (Exception ignored)
+        {
+        }
+        cacheLineBytes = value;
+    }
+
+    private MemoryUtils()
+    {
+    }
+
+    public static int getCacheLineBytes()
+    {
+        return cacheLineBytes;
+    }
+
+    public static int getIntegersPerCacheLine()
+    {
+        return getCacheLineBytes() >> 2;
+    }
+
+    public static int getLongsPerCacheLine()
+    {
+        return getCacheLineBytes() >> 3;
+    }
+
+}