/*

* 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: 

*

*/

#include <bigint.h>

#include <e32std.h>

#include <random.h>

#include "../common/inlines.h"

/** 

 * Copy constructor

 *

 * This function performs a shallow copy, 

 * i.e. the memory holding the integer is not copied.

 */

EXPORT_C RInteger::RInteger(const RInteger& aInteger)

	{

	*this = aInteger;

	}

/** 

 * Assignment operator

 * 

 * This function performs a shallow copy, 

 * i.e. the memory holding the integer is not copied.

 */

EXPORT_C RInteger& RInteger::operator=(const RInteger& aInteger)

	{

	iSize = aInteger.iSize;

	iPtr = aInteger.iPtr;

	return *this;

	}

/** 

 * Creates a new integer representing 0.

 * 

 * @return	An RInteger by value.

 */

EXPORT_C RInteger RInteger::NewL(void)

	{

	return NewL(TInteger::Zero());

	}

/** 

 * Creates a new integer object representing a specified value.

 * 

 * @param aValue	A descriptor containing the big-endian binary

 * 					representation of the value.

 * @return			An RInteger object representing the value.

 */

EXPORT_C RInteger RInteger::NewL(const TDesC8& aValue)

	{

	RInteger self;

	//Construct zero's memory beyond the size of aValue after construction

	self.CreateNewL(BytesToWords(aValue.Size()));

	self.Construct(aValue);

	return self;

	}

/** 

 * Creates an exact copy of an \c aInteger object.

 * 

 * @param aInteger	The integer you wish to copy

 * @return			An RInteger object representing an exact copy of 

 *					aInteger by value.

 */

EXPORT_C RInteger RInteger::NewL(const TInteger& aInteger)

	{

	RInteger self;

	//don't need to CleanNewL as we'll copy straight from aInteger

	self.CreateNewL(aInteger.Size());

	self.Construct(aInteger);

	return self;

	}

/** 

 * Creates a random integer uniformly distributed over [0, 2^aBits].

 * 

 * @param aBits	The number of bits you wish to randomly select.

 * @param aAttr	Enum specifying whether specific bits in the random number should

 *				be set.  See TRandomAttribute for more information.

 * @return		A random RInteger object in the range specified.

 */

EXPORT_C RInteger RInteger::NewRandomL(TUint aBits, TRandomAttribute aAttr)

	{

	RInteger self;

	self.CleanNewL(BitsToWords(aBits));

	CleanupStack::PushL(self);

	self.RandomizeL(aBits, aAttr);

	CleanupStack::Pop(&self); 

	return self;

	}

/** 

 * Creates a random integer uniformly distributed over [x | min <= x <= max].

 * 

 * @param aMin	The smallest possible value for the random integer (inclusive).

 * @param aMax	The largest possible value for the random integer (inclusive).

 * @return		A random RInteger object in the range specified.

 */

EXPORT_C RInteger RInteger::NewRandomL(const TInteger& aMin,

	const TInteger& aMax)

	{

	RInteger self;

	self.CleanNewL(aMax.Size());

	CleanupStack::PushL(self);

	self.RandomizeL(aMin, aMax);

	CleanupStack::Pop(&self);

	return self;

	}

/** 

 * Finds a random prime integer in the range of [2, 2^aBits].

 *

 * This is done by picking a random integer and using that as a starting point

 * for a sequential search for a prime.  To verify the primality of number, 

 * this algorithm uses a probablistic primality test.  This means that it is

 * possible, although extremely improbable, that the number returned is a pseudoprime.

 *

 * @param aBits	The number of bits you wish to randomly select your prime from.

 * @param aAttr	Enum specifying whether specific bits in the random number should

 *				be set.  See TRandomAttribute for more information.

 * @return		A random RInteger representing a probable prime (with very high

 *				probablity) in the range specified.

 */

EXPORT_C RInteger RInteger::NewPrimeL(TUint aBits, TRandomAttribute aAttr)

	{

	RInteger self;

	self.CleanNewL(BitsToWords(aBits));

	CleanupStack::PushL(self);

	self.PrimeRandomizeL(aBits, aAttr);

	CleanupStack::Pop(&self);

	return self;

	}

/** 

 * Creates a new integer from the value represented by \c aInteger.

 * 

 * @param aInteger	A signed word sized integer.

 * @return			An RInteger representation of aInteger by value.

 */

EXPORT_C RInteger RInteger::NewL(TInt aInteger)

	{

	RInteger self;

	self.CreateNewL(2);

	self.Construct(aInteger);

	return self;

	}

/** 

 * Creates a new integer from the value represented by \c aInteger.

 *

 * @param aInteger	An unsigned word sized integer.

 * @return			An RInteger representation of aInteger by value.

 */

EXPORT_C RInteger RInteger::NewL(TUint aInteger)

	{

	RInteger self;

	self.CreateNewL(2);

	self.Construct(aInteger);

	return self;

	}

/** 

 * Creates a new integer with a preallocated internal storage of \c aNumWords all

 * initialised to zero.

 *

 * The resulting RInteger object is logically equivalent to RInteger::NewL(0).

 * The only difference is that the internal storage requirements have been 

 * specified to be larger than the default. This is useful if you are about 

 * to perform an operation on this integer, that you know the resulting size

 * requirements of, and wish to avoid a heap resize.

 *

 * @param aNumWords	The number of words for to preallocated and zero fill.

 * @return			An RInteger object representing 0 with a preallocated 

 *					zero-filled internal storage of aNumWords.

 */

EXPORT_C RInteger RInteger::NewEmptyL(TUint aNumWords)

	{

	RInteger self;

	self.CleanNewL(aNumWords);

	//There's no construct as there isn't anything to do

	return self;

	}

/**

 * Creates an RInteger object with no associated internal (heap) storage.

 * 

 * All data members are initialised to zero.  It is safe (although not strictly necessary)

 * to push such an RInteger object onto the CleanupStack.  This is useful, for example, if

 * you want to pass an RInteger object by reference into a function and have it create

 * the representation of the actual integer for you.  

 *

 * Note that performing any operation on such an RInteger object other than the default

 * assignment operator or copy constructor will panic your code.

 * 

 * @return	A stack based class that has no associated internal storage and thus

 *			does not represent any number.

 */

EXPORT_C RInteger::RInteger(void)  

	{

	}

/** 

 * An overloaded TCleanupItem() allowing the RIntegers to be pushed,

 * popped, and destroyed via the CleanupStack like any other CBase derived object.

 */

EXPORT_C RInteger::operator TCleanupItem(void)

	{

	return TCleanupItem(&RInteger::CallClose, this);

	}

/** 

 * Helper function registered with the cleanup stack that just calls Close() for

 * this RInteger object.

 * 

 * @param aPtr	A pointer to the object for which clean-up is to be performed. 

 */

EXPORT_C void RInteger::CallClose(TAny* aPtr)

	{

	((RInteger*)aPtr)->Close();	

	}

/** 

 * Zeros and then frees any memory owned by this RInteger object.

 *  

 * An RInteger object that has been closed can safely fall off the stack.

 */

EXPORT_C void RInteger::Close(void)

	{

	if (iPtr)

		{

		Mem::FillZ(Ptr(), Size()*4);

		User::Free(Ptr());

		iSize = 0;

		iPtr = NULL;

		}

	}