--- old/src/share/classes/java/util/zip/CRC32.java	2013-05-30 12:42:14.000000000 -0400
+++ new/src/share/classes/java/util/zip/CRC32.java	2013-05-30 12:42:14.000000000 -0400
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 1996, 2011, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1996, 2013, 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
@@ -55,7 +55,10 @@
      * @param b the byte to update the checksum with
      */
     public void update(int b) {
-        crc = update(crc, b);
+        int c = ~ crc;
+        b = timesXtoThe32[(b ^ c) & 0xFF];
+        b = b ^ (c >>> 8);
+        crc = ~b;
     }
 
     /**
@@ -68,7 +71,12 @@
         if (off < 0 || len < 0 || off > b.length - len) {
             throw new ArrayIndexOutOfBoundsException();
         }
-        crc = updateBytes(crc, b, off, len);
+
+        if (len < javaCRCIfSmallerThan) {
+            crc = updateBytesSimple(crc, b, off, len);
+        } else {
+            crc = updateBytes(crc, b, off, len);
+        }
     }
 
     /**
@@ -131,4 +139,44 @@
 
     private native static int updateByteBuffer(int adler, long addr,
                                                int off, int len);
+
+    /**
+     *  Simple byte-at-a-time CRC for avoiding the overhead of native call.
+     *  Breakeven ranges between 60 and 100 bytes.
+     */
+    private static int updateBytesSimple(int crc, byte[] b, int off, int len) {
+        int[] a = timesXtoThe32;
+        if (a.length < 256)
+            throw new ArrayIndexOutOfBoundsException();
+        int c = ~crc;
+        for (int i = 0; i < len; i++ ) {
+            int x0 = b[i + off];
+            x0 = a[(x0 ^ c) & 0xFF];
+            c = x0 ^ (c >>> 8);
+        }
+        return ~c;
+    }
+
+    /**
+     * Returns true if CLMUL is both requested and supported.
+     */
+    private native static boolean init(int[] timesXtoThe32, boolean try_use_clmul);
+
+    /**
+     * timesXtoThe32[a] = rep(poly(a)*x**32)
+     */
+    static int[] timesXtoThe32;
+
+    /**
+     * Estimated CRC size below which the JNI overhead is too large.
+     * May be modified depending on platform properties.
+     */
+    static int javaCRCIfSmallerThan = 80;
+
+    static {
+      timesXtoThe32 = new int[256];
+      boolean try_use_clmul =
+           "true".equals(sun.misc.VM.getSavedProperty("sun.zip.clmulSupported"));
+      init(timesXtoThe32, try_use_clmul);
+    }
 }