1 // Copyright (c) 2004-2009 Nokia Corporation and/or its subsidiary(-ies).

     2 // All rights reserved.

     3 // This component and the accompanying materials are made available

     4 // under the terms of the License "Eclipse Public License v1.0"

     5 // which accompanies this distribution, and is available

     6 // at the URL "http://www.eclipse.org/legal/epl-v10.html".

     7 //

     8 // Initial Contributors:

     9 // Nokia Corporation - initial contribution.

    10 //

    11 // Contributors:

    12 //

    13 // Description:

    14 // Utility functions for the Mass Storage file system.

    15 // 

    16 //

    17 

    18 /**

    19  @file

    20  @internalTechnology

    21 */

    22 

    23 #include <e32std.h>

    24 #include <e32std_private.h>

    25 

    26 /**

    27 Returns ETrue if aNum is a power of two

    28 */

    29 GLDEF_C TBool IsPowerOfTwo(TInt aNum)

    30 	{

    31 

    32 	if (aNum==0)

    33 		return(EFalse);

    34 

    35 	while(aNum)

    36 		{

    37 		if (aNum & 0x01)

    38 			{

    39 			if (aNum>>1) 

    40 				return EFalse;

    41 			break;

    42 			}

    43 		aNum>>=1;

    44 		}

    45 	return ETrue;

    46 	}

    47 

    48 /**

    49 Returns the position of the highest bit in aNum or -1 if aNum == 0

    50 */

    51 GLDEF_C TInt Log2(TInt aNum)

    52 	{

    53 

    54 	TInt res=-1;

    55 	while(aNum)

    56 		{

    57 		res++;

    58 		aNum>>=1;

    59 		}

    60 	return(res);

    61 	}

    62