--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/crypto/weakcryptospi/source/bigint/windowslider.h	Fri Nov 06 13:21:00 2009 +0200
@@ -0,0 +1,62 @@
+/*
+* Copyright (c) 2003-2009 Nokia Corporation and/or its subsidiary(-ies).
+* All rights reserved.
+* This component and the accompanying materials are made available
+* under the terms of the License "Eclipse Public License v1.0"
+* which accompanies this distribution, and is available
+* at the URL "http://www.eclipse.org/legal/epl-v10.html".
+*
+* Initial Contributors:
+* Nokia Corporation - initial contribution.
+*
+* Contributors:
+*
+* Description: 
+* TWindowSlider class implementation
+*
+*/
+
+
+/**
+ @file 
+ @internalComponent
+*/
+ 
+#ifndef __WINDOWSLIDER_H__
+#define __WINDOWSLIDER_H__
+
+#include <e32std.h>
+
+class TInteger; 
+/** Utility class used by our fast exponentiation routines.\n\n
+ * See HAC 14.85 for an explanation of how window sliding helps speed things up.
+ * @internalComponent
+ */
+class TWindowSlider
+{
+public:
+	/** 
+	 * @param aExp The exponent you are using.
+	 * @param aWindowSize The window size.  Leave as default value for the
+	 * constructor to pick a window size appropriate for the given aExp
+	 * @internalComponent
+	 */
+	TWindowSlider(const TInteger& aExp, TUint aWindowSize=0);
+	/**
+	 * Finds the next "window" as defined by HAC 14.85.  The actual bitstring
+	 * value is in iValue and it's length in iLength.  These remain valid until
+	 * the next call to FindNextWindow()
+	 */
+	void FindNextWindow(TUint aBegin);
+	inline TUint WindowSize(void) {return iSize;}
+	inline TUint Value(void) {return iValue;}
+	inline TUint Length(void) {return iLength;}
+
+private:
+	const TInteger& iExp; ///the exponent all this is being calculated on
+	TUint iSize;  ///The size of the sliding window
+	TUint iValue; ///the value found by the most recent FindNextWindow() call
+	TUint iLength;///the bit length of the iValue
+};
+
+#endif