diff -r 8873e6835f7b -r dd83586b62d6 crypto/weakcrypto/source/bigint/bigint.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/crypto/weakcrypto/source/bigint/bigint.cpp	Fri Jun 11 15:32:35 2010 +0300
@@ -0,0 +1,1166 @@
+/*
+* 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 <euserext.h>
+#include <securityerr.h>
+#include "words.h"
+#include "algorithms.h"
+#include "windowslider.h"
+#include "stackinteger.h"
+#include "mont.h"
+
+
+/**
+* Creates a new buffer containing the big-endian binary representation of this
+* integer.
+*
+* Note that it does not support the exporting of negative integers.
+*
+* @return	The new buffer.
+* 
+* @leave KErrNegativeExportNotSupported	If this instance is a negative integer.
+*
+*/
+EXPORT_C HBufC8* TInteger::BufferLC() const
+	{
+	if(IsNegative())
+		{
+		User::Leave(KErrNegativeExportNotSupported);
+		}
+	TUint bytes = ByteCount();
+	HBufC8* buf = HBufC8::NewMaxLC(bytes);
+	TUint8* bufPtr = (TUint8*)(buf->Ptr());
+	TUint8* regPtr = (TUint8*)Ptr();
+
+	// we internally store the number little endian, as a string we want it big
+	// endian
+	for(TUint i=0,j=bytes-1; i<bytes; )
+		{
+		bufPtr[i++] = regPtr[j--];
+		}
+	return buf;
+	}
+
+EXPORT_C HBufC8* TInteger::BufferWithNoTruncationLC() const
+ 	{
+ 	if(IsNegative())
+ 		{
+ 		User::Leave(KErrNegativeExportNotSupported);
+ 		}
+ 	
+ 	TUint wordCount = Size();
+ 	TUint bytes = (wordCount)*WORD_SIZE;
+     
+  	HBufC8* buf = HBufC8::NewMaxLC(bytes);
+ 	TUint8* bufPtr = (TUint8*)(buf->Ptr());
+	TUint8* regPtr = (TUint8*)Ptr();
+	for(TUint i=0,j=bytes-1; i<bytes; )
+ 		{
+ 		bufPtr[i++] = regPtr[j--];
+ 		}
+  
+	return buf;
+	}
+
+/** 
+* Gets the number of words required to represent this RInteger.
+* 
+* @return	The size of the integer in words.
+*
+*/
+EXPORT_C TUint TInteger::WordCount() const
+	{
+	return CountWords(Ptr(), Size());
+	}
+
+/**
+* Gets the number of bytes required to represent this RInteger.
+* 
+* @return	The size of the integer in bytes.
+* 
+*/
+EXPORT_C TUint TInteger::ByteCount() const
+	{
+	TUint wordCount = WordCount();
+	if(wordCount)
+		{
+		return (wordCount-1)*WORD_SIZE + BytePrecision((Ptr())[wordCount-1]);
+		}
+	else 
+		{
+		return 0;
+		}
+	}
+
+/** 
+* Get the number of bits required to represent this RInteger.
+* 
+* @return	The size of the integer in bits.
+* 
+*/
+EXPORT_C TUint TInteger::BitCount() const
+	{
+	TUint wordCount = WordCount();
+	if(wordCount)
+		{
+		return (wordCount-1)*WORD_BITS + BitPrecision(Ptr()[wordCount-1]);
+		}
+	else 
+		{
+		return 0;
+		}
+	}
+
+
+//These 3 declarations instantiate a constant 0, 1, 2 for ease of use and
+//quick construction elsewhere in the code.  Note that the functions
+//returning references to this static data return const references as you can't
+//modify the ROM ;)
+//word 0: Size of storage in words
+//word 1: Pointer to storage
+//word 2: LSW of storage
+//word 3: MSW of storage
+//Note that the flag bits in word 1 (Ptr()) are zero in the case of a positive
+//stack based integer (SignBit == 0, IsHeapBasedBit == 0)
+const TUint KBigintZero[4] = {2, (TUint)(KBigintZero+2), 0, 0};
+const TUint KBigintOne[4] = {2, (TUint)(KBigintOne+2), 1, 0};
+const TUint KBigintTwo[4] = {2, (TUint)(KBigintTwo+2), 2, 0};
+
+/** 
+ * Gets the TInteger that represents zero
+ *
+ * @return	The TInteger representing zero
+ */
+EXPORT_C const TInteger& TInteger::Zero(void)
+	{
+	return *reinterpret_cast<const TStackInteger64*>(KBigintZero);
+	}
+
+/** 
+ * Gets the TInteger that represents one
+ *
+ * @return	The TInteger representing one
+ */
+EXPORT_C const TInteger& TInteger::One(void)
+	{
+	return *reinterpret_cast<const TStackInteger64*>(KBigintOne);
+	}
+	
+/** 
+ * Gets the TInteger that represents two
+ *
+ * @return	The TInteger representing two
+ */
+EXPORT_C const TInteger& TInteger::Two(void)
+	{
+	return *reinterpret_cast<const TStackInteger64*>(KBigintTwo);
+	}
+
+EXPORT_C RInteger TInteger::PlusL(const TInteger& aOperand) const
+	{
+	RInteger sum;
+    if (NotNegative())
+		{
+        if (aOperand.NotNegative())
+            sum = PositiveAddL(*this, aOperand);
+        else
+            sum = PositiveSubtractL(*this, aOperand);
+		}
+    else
+		{
+        if (aOperand.NotNegative())
+            sum = PositiveSubtractL(aOperand, *this);
+        else
+			{
+            sum = PositiveAddL(*this, aOperand);
+			sum.SetSign(TInteger::ENegative);
+			}
+		}
+	return sum;
+	}
+
+EXPORT_C RInteger TInteger::MinusL(const TInteger& aOperand) const
+	{
+	RInteger diff;
+    if (NotNegative())
+		{
+        if (aOperand.NotNegative())
+            diff = PositiveSubtractL(*this, aOperand);
+        else
+            diff = PositiveAddL(*this, aOperand);
+		}
+    else
+		{
+        if (aOperand.NotNegative())
+			{
+            diff = PositiveAddL(*this, aOperand);
+			diff.SetSign(TInteger::ENegative);
+			}
+        else
+            diff = PositiveSubtractL(aOperand, *this);
+		}
+	return diff;
+	}
+
+EXPORT_C RInteger TInteger::TimesL(const TInteger& aOperand) const
+	{
+	RInteger product = PositiveMultiplyL(*this, aOperand);
+
+	if (NotNegative() != aOperand.NotNegative())
+		{
+		product.Negate();
+		}
+	return product;
+	}
+
+EXPORT_C RInteger TInteger::DividedByL(const TInteger& aOperand) const
+	{
+	RInteger quotient;
+	RInteger remainder;
+	DivideL(remainder, quotient, *this, aOperand);
+	remainder.Close();
+	return quotient;
+	}
+
+EXPORT_C RInteger TInteger::DividedByL(TUint aOperand) const
+	{
+	TUint remainder;
+	RInteger quotient;
+	DivideL(remainder, quotient, *this, aOperand);
+	return quotient;
+	}
+
+EXPORT_C RInteger TInteger::ModuloL(const TInteger& aOperand) const
+	{
+	RInteger remainder;
+	RInteger quotient;
+	DivideL(remainder, quotient, *this, aOperand);
+	quotient.Close();
+	return remainder;
+	}
+
+EXPORT_C TUint TInteger::ModuloL(TUint aOperand) const
+	{
+	if(!aOperand)
+		{
+		User::Leave(KErrDivideByZero);
+		}
+	return Modulo(*this, aOperand);
+	}
+
+EXPORT_C RInteger TInteger::SquaredL() const
+	{
+	//PositiveMultiplyL optimises for the squaring case already
+	//Any number squared is positive, no need for negative handling in TimesL
+	return PositiveMultiplyL(*this, *this);
+	}
+
+EXPORT_C RInteger TInteger::ExponentiateL(const TInteger& aExponent) const
+	{
+	//See HAC 14.85
+
+	// 1.1 Precomputation
+	// g1 <- g
+	// g2 <- g^2
+	RInteger g2 = SquaredL();
+	CleanupStack::PushL(g2);
+	RInteger g1 = RInteger::NewL(*this);
+	CleanupStack::PushL(g1);
+	TWindowSlider slider(aExponent);
+
+	// 1.2 
+	// For i from 1 to (2^(k-1) -1) do g2i+1 <- g2i-1 * g2
+	TUint count = (1 << (slider.WindowSize()-1)) - 1; //2^(k-1) -1
+	RRArray<RInteger> powerArray(count+1); //+1 because we append g1
+	User::LeaveIfError(powerArray.Append(g1));
+	CleanupStack::Pop(); //g1
+	CleanupClosePushL(powerArray);
+	for(TUint k=1; k <= count; k++)
+		{
+		RInteger g2iplus1 = g2.TimesL(powerArray[k-1]);
+		//This append can't fail as the granularity is set high enough
+		//plus we've already called Append once which will alloc to the 
+		//set granularity
+		powerArray.Append(g2iplus1);
+		}
+
+	// 2 A <- 1, i <- t
+	RInteger A = RInteger::NewL(One());
+	CleanupStack::PushL(A);
+	TInt i = aExponent.BitCount() - 1;
+
+	// 3 While i>=0 do:
+	while( i>=0 )
+		{
+		// 3.1 If ei == 0 then A <- A^2
+		if(!aExponent.Bit(i))
+			{
+			A *= A;
+			i--;
+			}
+		// 3.2 Find longest bitstring ei,ei-1,...,el s.t. i-l+1<=k and el==1
+		// and do:
+		// A <- (A^2^(i-l+1)) * g[the index indicated by the bitstring value]
+		else
+			{
+			slider.FindNextWindow(i);
+			assert(slider.Length() >= 1);
+			for(TUint j=0; j<slider.Length(); j++)
+				{
+				A *= A;
+				}
+			A *= powerArray[slider.Value()>>1];
+			i -= slider.Length();
+			}
+		}
+	CleanupStack::Pop(&A);
+	CleanupStack::PopAndDestroy(2, &g2); //powerArray, g2
+	return A;
+	}
+
+EXPORT_C RInteger TInteger::ModularMultiplyL(const TInteger& aA, const TInteger& aB,
+	const TInteger& aMod) 
+	{
+	RInteger product = aA.TimesL(aB);
+	CleanupStack::PushL(product);
+	RInteger reduced = product.ModuloL(aMod);
+	CleanupStack::PopAndDestroy(&product); 
+	return reduced;
+	}
+
+EXPORT_C RInteger TInteger::ModularExponentiateL(const TInteger& aBase, 
+	const TInteger& aExp, const TInteger& aMod) 
+	{
+	CMontgomeryStructure* mont = CMontgomeryStructure::NewLC(aMod);
+	RInteger result = RInteger::NewL(mont->ExponentiateL(aBase, aExp));
+	CleanupStack::PopAndDestroy(mont);
+	return result;
+	}
+
+EXPORT_C RInteger TInteger::GCDL(const TInteger& aOperand) const
+	{
+	//Binary GCD algorithm -- see HAC 14.4.1
+	//with a slight variation -- our g counts shifts rather than actually
+	//shifting.  We then do one shift at the end.
+	assert(NotNegative());
+	assert(aOperand.NotNegative());
+
+	RInteger x = RInteger::NewL(*this);
+	CleanupStack::PushL(x);
+	RInteger y = RInteger::NewL(aOperand);
+	CleanupStack::PushL(y);
+
+	// 1 Ensure x >= y
+	if( x < y )
+		{
+		TClassSwap(x, y);
+		}
+
+	TUint g = 0;
+	// 2 while x and y even x <- x/2, y <- y/2
+	while( x.IsEven() && y.IsEven() )
+		{
+		x >>= 1;
+		y >>= 1;
+		++g;
+		}
+	// 3 while x != 0
+	while( x.NotZero() )
+		{
+		// 3.1 while x even x <- x/2
+		while( x.IsEven() )
+			{
+			x >>= 1;
+			}
+		// 3.2 while y even y <- y/2
+		while( y.IsEven() )
+			{
+			y >>= 1;
+			}
+		// 3.3 t <- abs(x-y)/2
+		RInteger t = x.MinusL(y);
+		t >>= 1;
+		t.SetSign(TInteger::EPositive);
+
+		// 3.4 If x>=y then x <- t else y <- t
+		if( x >= y )
+			{
+			x.Set(t);
+			}
+		else 
+			{
+			y.Set(t);
+			}
+		}
+	
+	// 4 Return (g*y) (equiv to y<<=g as our g was counting shifts not actually
+	//shifting)
+	y <<= g;
+	CleanupStack::Pop(&y);
+	CleanupStack::PopAndDestroy(&x); 
+	return y;
+	}
+
+EXPORT_C RInteger TInteger::InverseModL(const TInteger& aMod) const
+	{
+	assert(aMod.NotNegative());
+
+	RInteger result;
+	if(IsNegative() || *this>=aMod)
+		{
+		RInteger temp = ModuloL(aMod);
+		CleanupClosePushL(temp);
+		result = temp.InverseModL(aMod);
+		CleanupStack::PopAndDestroy(&temp);
+		return result;
+		}
+
+	if(aMod.IsEven())
+		{
+		if( !aMod || IsEven() )
+			{
+			return RInteger::NewL(Zero());
+			}
+		if( *this == One() )
+			{
+			return RInteger::NewL(One());
+			}
+		RInteger u = aMod.InverseModL(*this); 
+		CleanupClosePushL(u);
+		if(!u)
+			{
+			result = RInteger::NewL(Zero());
+			}
+		else 
+			{
+			//calculates (aMod*(*this-u)+1)/(*this) 
+			result = MinusL(u);
+			CleanupClosePushL(result);
+			result *= aMod;
+			++result;
+			result /= *this;
+			CleanupStack::Pop(&result); 
+			}
+		CleanupStack::PopAndDestroy(&u);
+		return result;
+		}
+
+	result = RInteger::NewEmptyL(aMod.Size());
+	CleanupClosePushL(result);
+	RInteger workspace = RInteger::NewEmptyL(aMod.Size() * 4);
+	TUint k = AlmostInverse(result.Ptr(), workspace.Ptr(), Ptr(), Size(),
+		aMod.Ptr(), aMod.Size());
+	DivideByPower2Mod(result.Ptr(), result.Ptr(), k, aMod.Ptr(), aMod.Size());
+	workspace.Close();
+	CleanupStack::Pop(&result);
+
+	return result;
+	}
+
+EXPORT_C TInteger& TInteger::operator+=(const TInteger& aOperand)
+	{
+	this->Set(PlusL(aOperand));
+    return *this;
+	}
+
+EXPORT_C TInteger& TInteger::operator-=(const TInteger& aOperand)
+	{
+	this->Set(MinusL(aOperand));
+    return *this;
+	}
+
+EXPORT_C TInteger& TInteger::operator*=(const TInteger& aOperand)
+	{
+	this->Set(TimesL(aOperand));
+	return *this;
+	}
+
+EXPORT_C TInteger& TInteger::operator/=(const TInteger& aOperand)
+	{
+	this->Set(DividedByL(aOperand));
+	return *this;
+	}
+
+EXPORT_C TInteger& TInteger::operator%=(const TInteger& aOperand)
+	{
+	this->Set(ModuloL(aOperand));
+	return *this;
+	}
+
+EXPORT_C TInteger& TInteger::operator+=(TInt aOperand)
+	{
+	TStackInteger64 operand(aOperand);
+	*this += operand;
+	return *this;
+	}
+
+EXPORT_C TInteger& TInteger::operator-=(TInt aOperand)
+	{
+	TStackInteger64 operand(aOperand);
+	*this -= operand;
+	return *this;
+	}
+
+EXPORT_C TInteger& TInteger::operator*=(TInt aOperand)
+	{
+	TStackInteger64 operand(aOperand);
+	*this *= operand;
+	return *this;
+	}
+
+EXPORT_C TInteger& TInteger::operator/=(TInt aOperand)
+	{
+	TStackInteger64 operand(aOperand);
+	*this /= operand;
+	return *this;
+	}
+
+EXPORT_C TInteger& TInteger::operator%=(TInt aOperand)
+	{
+	TStackInteger64 operand(aOperand);
+	assert(operand.NotNegative());
+	*this %= operand;
+	return *this;
+	}
+
+EXPORT_C TInteger& TInteger::operator--()
+	{
+    if (IsNegative())
+		{
+        if (Increment(Ptr(), Size()))
+			{
+            CleanGrowL(2*Size());
+            (Ptr())[Size()/2]=1;
+			}
+		}
+    else
+		{
+        if (Decrement(Ptr(), Size()))
+			{
+			this->CopyL(-1);
+			}
+		}
+    return *this;	
+	}
+
+EXPORT_C TInteger& TInteger::operator++()
+	{
+	if(NotNegative())
+		{
+		if(Increment(Ptr(), Size()))
+			{
+			CleanGrowL(2*Size());
+			(Ptr())[Size()/2]=1;
+			}
+		}
+	else
+		{
+		DecrementNoCarry(Ptr(), Size());
+		if(WordCount()==0)
+			{
+			this->CopyL(Zero());
+			}
+		}
+	return *this;
+	}
+
+EXPORT_C TInteger& TInteger::operator <<=(TUint aBits)
+	{
+	const TUint wordCount = WordCount();
+	const TUint shiftWords = aBits / WORD_BITS;
+	const TUint shiftBits = aBits % WORD_BITS;
+
+	CleanGrowL(wordCount+BitsToWords(aBits));
+	ShiftWordsLeftByWords(Ptr(), wordCount + shiftWords, shiftWords);
+	ShiftWordsLeftByBits(Ptr()+shiftWords, wordCount + BitsToWords(shiftBits), 
+		shiftBits);
+	return *this;
+	}
+
+EXPORT_C TInteger& TInteger::operator >>=(TUint aBits)
+	{
+	const TUint wordCount = WordCount();
+	const TUint shiftWords = aBits / WORD_BITS;
+	const TUint shiftBits = aBits % WORD_BITS;
+
+	ShiftWordsRightByWords(Ptr(), wordCount, shiftWords);
+	if(wordCount > shiftWords)
+		{
+		ShiftWordsRightByBits(Ptr(), wordCount - shiftWords, shiftBits);
+		}
+	if(IsNegative() && WordCount()==0) // avoid negative 0
+		{
+		SetSign(EPositive);
+		}
+	return *this;
+	}
+
+EXPORT_C TInt TInteger::UnsignedCompare(const TInteger& aThat) const
+	{
+	TUint size = WordCount();
+	TUint thatSize = aThat.WordCount();
+
+	if( size == thatSize )
+		return Compare(Ptr(), aThat.Ptr(), size);
+	else
+		return size > thatSize ? 1 : -1;
+	}
+
+EXPORT_C TInt TInteger::SignedCompare(const TInteger& aThat) const
+	{
+    if (NotNegative())
+		{
+        if (aThat.NotNegative())
+            return UnsignedCompare(aThat);
+        else
+            return 1;
+		}
+    else
+		{
+        if (aThat.NotNegative())
+            return -1;
+        else
+            return -UnsignedCompare(aThat);
+		}
+	}
+
+EXPORT_C TBool TInteger::operator!() const
+	{
+	//Ptr()[0] is just a quick way of weeding out non-zero numbers without
+	//doing a full WordCount() == 0.  Very good odds that a non-zero number
+	//will have a bit set in the least significant word
+	return IsNegative() ? EFalse : (Ptr()[0]==0 && WordCount()==0);
+	}
+
+EXPORT_C TInt TInteger::SignedCompare(TInt aInteger) const
+	{
+	TStackInteger64 temp(aInteger);
+	return SignedCompare(temp);
+	}
+
+/* TBool IsPrimeL(void) const 
+ * and all primality related functions are implemented in primes.cpp */
+
+EXPORT_C TBool TInteger::Bit(TUint aBitPos) const
+	{
+	if( aBitPos/WORD_BITS >= Size() )
+		{
+		return 0;
+		}
+	else 
+		{
+		return (((Ptr())[aBitPos/WORD_BITS] >> (aBitPos % WORD_BITS)) & 1);
+		}
+	}
+
+EXPORT_C void TInteger::SetBit(TUint aBitPos) 
+	{
+	if( aBitPos/WORD_BITS < Size() )
+		{
+		ArraySetBit(Ptr(), aBitPos);
+		}
+	}
+
+EXPORT_C void TInteger::Negate() 
+	{
+	if(!!(*this)) //don't flip sign if *this==0
+		{
+		SetSign(TSign((~Sign())&KSignMask));
+		}
+	}
+
+EXPORT_C TInt TInteger::ConvertToLongL(void) const
+	{
+	if(!IsConvertableToLong())
+		{
+		User::Leave(KErrTotalLossOfPrecision);
+		}
+	return ConvertToLong();
+	}
+
+EXPORT_C void TInteger::CopyL(const TInteger& aInteger, TBool aAllowShrink)
+	{
+	if(aAllowShrink)
+		{
+		CleanResizeL(aInteger.Size());
+		}
+	else
+		{
+		CleanGrowL(aInteger.Size());
+		}
+	Construct(aInteger);
+	}
+
+EXPORT_C void TInteger::CopyL(TInt aInteger, TBool aAllowShrink)
+	{
+	if(aAllowShrink)
+		{
+		CleanResizeL(2);
+		}
+	else
+		{
+		CleanGrowL(2);
+		}
+	Construct(aInteger);
+	}
+
+EXPORT_C void TInteger::Set(const RInteger& aInteger)
+	{
+	assert(IsHeapBased());
+	Mem::FillZ(Ptr(), WordsToBytes(Size()));
+	User::Free(Ptr());
+	iPtr = aInteger.iPtr;
+	iSize = aInteger.iSize;
+	}
+
+RInteger TInteger::PositiveAddL(const TInteger &aA, const TInteger& aB) const
+	{
+	RInteger sum = RInteger::NewEmptyL(CryptoMax(aA.Size(), aB.Size()));
+	const word aSize = aA.Size();
+	const word bSize = aB.Size();
+	const word* const aReg = aA.Ptr();
+	const word* const bReg = aB.Ptr();
+	word* const sumReg = sum.Ptr();
+
+	word carry;
+	if (aSize == bSize)
+		carry = Add(sumReg, aReg, bReg, aSize);
+	else if (aSize > bSize)
+		{
+		carry = Add(sumReg, aReg, bReg, bSize);
+		CopyWords(sumReg+bSize, aReg+bSize, aSize-bSize);
+		carry = Increment(sumReg+bSize, aSize-bSize, carry);
+		}
+	else
+		{
+		carry = Add(sumReg, aReg, bReg, aSize);
+		CopyWords(sumReg+aSize, bReg+aSize, bSize-aSize);
+		carry = Increment(sumReg+aSize, bSize-aSize, carry);
+		}
+
+	if (carry)
+		{
+		CleanupStack::PushL(sum);
+		sum.CleanGrowL(2*sum.Size());
+		CleanupStack::Pop(&sum);
+		sum.Ptr()[sum.Size()/2] = 1;
+		}
+	sum.SetSign(TInteger::EPositive);
+	return sum;
+	}
+
+RInteger TInteger::PositiveSubtractL(const TInteger &aA, const TInteger& aB) const
+	{
+	RInteger diff = RInteger::NewEmptyL(CryptoMax(aA.Size(), aB.Size()));
+	unsigned aSize = aA.WordCount();
+	aSize += aSize%2;
+	unsigned bSize = aB.WordCount();
+	bSize += bSize%2;
+	const word* const aReg = aA.Ptr();
+	const word* const bReg = aB.Ptr();
+	word* const diffReg = diff.Ptr();
+
+	if (aSize == bSize)
+		{
+		if (Compare(aReg, bReg, aSize) >= 0)
+			{
+			Subtract(diffReg, aReg, bReg, aSize);
+			diff.SetSign(TInteger::EPositive);
+			}
+		else
+			{
+			Subtract(diffReg, bReg, aReg, aSize);
+			diff.SetSign(TInteger::ENegative);
+			}
+		}
+	else if (aSize > bSize)
+		{
+		word borrow = Subtract(diffReg, aReg, bReg, bSize);
+		CopyWords(diffReg+bSize, aReg+bSize, aSize-bSize);
+		borrow = Decrement(diffReg+bSize, aSize-bSize, borrow);
+		assert(!borrow);
+		diff.SetSign(TInteger::EPositive);
+		}
+	else
+		{
+		word borrow = Subtract(diffReg, bReg, aReg, aSize);
+		CopyWords(diffReg+aSize, bReg+aSize, bSize-aSize);
+		borrow = Decrement(diffReg+aSize, bSize-aSize, borrow);
+		assert(!borrow);
+		diff.SetSign(TInteger::ENegative);
+		}
+	return diff;
+	}
+
+RInteger TInteger::PositiveMultiplyL(const TInteger &aA, const TInteger &aB) const
+	{
+	unsigned aSize = RoundupSize(aA.WordCount());
+	unsigned bSize = RoundupSize(aB.WordCount());
+
+	RInteger product = RInteger::NewEmptyL(aSize+bSize);
+	CleanupClosePushL(product);
+
+	RInteger workspace = RInteger::NewEmptyL(aSize + bSize);
+	AsymmetricMultiply(product.Ptr(), workspace.Ptr(), aA.Ptr(), aSize, aB.Ptr(), 
+		bSize);
+	workspace.Close();
+	CleanupStack::Pop(&product);
+	return product;
+	}
+
+TUint TInteger::Modulo(const TInteger& aDividend, TUint aDivisor) const
+	{
+	assert(aDivisor);
+	TUint i = aDividend.WordCount();
+	TUint remainder = 0;
+	while(i--)
+		{
+		remainder = TUint(MAKE_DWORD(aDividend.Ptr()[i], remainder) % aDivisor);
+		}
+	return remainder;
+	}
+
+void TInteger::PositiveDivide(TUint& aRemainder, TInteger& aQuotient, 
+	const TInteger& aDividend, TUint aDivisor) const
+	{
+	assert(aDivisor);
+
+	TUint i = aDividend.WordCount();
+	assert(aQuotient.Size() >= RoundupSize(i));
+	assert(aQuotient.Sign() == TInteger::EPositive);
+	aRemainder = 0;
+	while(i--)
+		{
+		aQuotient.Ptr()[i] = 
+			TUint(MAKE_DWORD(aDividend.Ptr()[i], aRemainder) / aDivisor);
+		aRemainder = 
+			TUint(MAKE_DWORD(aDividend.Ptr()[i], aRemainder) % aDivisor);
+		}
+	}
+
+void TInteger::DivideL(TUint& aRemainder, RInteger& aQuotient,
+	const TInteger& aDividend, TUint aDivisor) const
+	{
+	if(!aDivisor)
+		{
+		User::Leave(KErrDivideByZero);
+		}
+	
+	TUint i = aDividend.WordCount();
+	aQuotient.CleanNewL(RoundupSize(i));
+	PositiveDivide(aRemainder, aQuotient, aDividend, aDivisor);
+
+	if(aDividend.NotNegative())
+		{
+		aQuotient.SetSign(TInteger::EPositive);
+		}
+	else
+		{
+		aQuotient.SetSign(TInteger::ENegative);
+		if(aRemainder)
+			{
+			--aQuotient;
+			aRemainder = aDivisor = aRemainder;
+			}
+		}
+	}
+
+void TInteger::PositiveDivideL(RInteger &aRemainder, RInteger &aQuotient,
+	const TInteger &aDividend, const TInteger &aDivisor) const
+	{
+	unsigned dividendSize = aDividend.WordCount();
+	unsigned divisorSize = aDivisor.WordCount();
+
+	if (!divisorSize)
+		{
+		User::Leave(KErrDivideByZero);
+		}
+
+	if (aDividend.UnsignedCompare(aDivisor) == -1)
+		{
+		aRemainder.CreateNewL(aDividend.Size());
+		CleanupStack::PushL(aRemainder);
+		aRemainder.CopyL(aDividend); //set remainder to a
+		aRemainder.SetSign(TInteger::EPositive);
+		aQuotient.CleanNewL(2); //Set quotient to zero
+		CleanupStack::Pop(&aRemainder);
+		return;
+		}
+
+	dividendSize += dividendSize%2;	// round up to next even number
+	divisorSize += divisorSize%2;
+
+	aRemainder.CleanNewL(divisorSize);
+	CleanupStack::PushL(aRemainder);
+	aQuotient.CleanNewL(dividendSize-divisorSize+2);
+	CleanupStack::PushL(aQuotient);
+
+	RInteger T = RInteger::NewEmptyL(dividendSize+2*divisorSize+4);
+	Divide(aRemainder.Ptr(), aQuotient.Ptr(), T.Ptr(), aDividend.Ptr(), 
+		dividendSize, aDivisor.Ptr(), divisorSize);
+	T.Close();
+	CleanupStack::Pop(2, &aRemainder); //aQuotient, aRemainder
+	}
+
+void TInteger::DivideL(RInteger& aRemainder, RInteger& aQuotient, 
+	const TInteger& aDividend, const TInteger& aDivisor) const
+    {
+    PositiveDivideL(aRemainder, aQuotient, aDividend, aDivisor);
+
+    if (aDividend.IsNegative())
+        {
+        aQuotient.Negate();
+        if (aRemainder.NotZero())
+            {
+            --aQuotient;
+			assert(aRemainder.Size() <= aDivisor.Size());
+			Subtract(aRemainder.Ptr(), aDivisor.Ptr(), aRemainder.Ptr(), 
+				aRemainder.Size());
+            }
+        }
+
+    if (aDivisor.IsNegative())
+        aQuotient.Negate();
+    }
+
+TInt TInteger::ConvertToLong(void) const
+	{
+	TUint value = ConvertToUnsignedLong();
+	return Sign() == EPositive ? value : -(static_cast<TInt>(value));
+	}
+
+TBool TInteger::IsConvertableToLong(void) const
+	{
+	if(WordCount() > 1)
+		{
+		return EFalse;
+		}
+	TUint value = (Ptr())[0];
+	if(Sign() == EPositive)
+		{
+		return static_cast<TInt>(value) >= 0;
+		}
+	else
+		{
+		return -(static_cast<TInt>(value)) < 0;
+		}
+	}
+
+void TInteger::RandomizeL(TUint aBits, TRandomAttribute aAttr)
+	{
+	if(!aBits)
+		{
+		return;
+		}
+	const TUint bytes = BitsToBytes(aBits);
+	const TUint words = BitsToWords(aBits);
+	CleanGrowL(words);
+	TPtr8 buf((TUint8*)(Ptr()), bytes, WordsToBytes(Size()));
+	TUint bitpos = aBits % BYTE_BITS;
+	GenerateRandomBytesL(buf);
+	//mask with 0 all bits above the num requested in the most significant byte
+	if(bitpos)
+		{
+		buf[bytes-1] = TUint8( buf[bytes-1] & ((1L << bitpos) - 1) );
+		}
+	//set most significant (top) bit 
+	if(aAttr == ETopBitSet || aAttr == ETop2BitsSet)
+		{
+		SetBit(aBits-1); //Set bit counts from 0
+		assert(BitCount() == aBits);
+		assert(Bit(aBits-1));
+		}
+	//set 2nd bit from top
+	if(aAttr == ETop2BitsSet)
+		{
+		SetBit(aBits-2); //Set bit counts from 0
+		assert(BitCount() == aBits);
+		assert(Bit(aBits-1));
+		assert(Bit(aBits-2));
+		}
+	}
+
+void TInteger::RandomizeL(const TInteger& aMin, const TInteger& aMax)
+	{
+	assert(aMax > aMin);
+	assert(aMin.NotNegative());
+	RInteger range = RInteger::NewL(aMax);
+	CleanupStack::PushL(range);
+	range -= aMin;
+	const TUint bits = range.BitCount();
+
+	//if we find a number < range then aMin+range < aMax 
+	do
+		{
+		RandomizeL(bits, EAllBitsRandom);
+		} 
+	while(*this > range);
+
+	*this += aMin;
+	CleanupStack::PopAndDestroy(&range);
+	}
+
+/* void PrimeRandomizeL(TUint aBits, TRandomAttribute aAttr)
+ * and all primality related functions are implemented in primes.cpp */
+
+void TInteger::CreateNewL(TUint aNewSize)
+	{
+	//should only be called on construction
+	assert(!iPtr);
+	
+	TUint newSize = RoundupSize(aNewSize);
+	SetPtr((TUint*)User::AllocL(WordsToBytes(newSize)));
+	SetSize(newSize);
+	SetHeapBased();
+	}
+
+void TInteger::CleanNewL(TUint aNewSize)
+	{
+	CreateNewL(aNewSize);
+	Mem::FillZ(Ptr(), WordsToBytes(Size())); //clear integer storage
+	}
+
+void TInteger::CleanGrowL(TUint aNewSize)
+	{
+	assert(IsHeapBased());
+	TUint newSize = RoundupSize(aNewSize);
+	TUint oldSize = Size();
+	if(newSize > oldSize)
+		{
+		TUint* oldPtr = Ptr();
+		//1) allocate new memory and set ptr and size
+		SetPtr((TUint*)User::AllocL(WordsToBytes(newSize)));
+		SetSize(newSize);
+		//2) copy old mem to new mem
+		Mem::Copy(Ptr(), oldPtr, WordsToBytes(oldSize));
+		//3) zero all old memory
+		Mem::FillZ(oldPtr, WordsToBytes(oldSize));
+		//4) give back old memory
+		User::Free(oldPtr);
+		//5) zero new memory from end of copy to end of growth
+		Mem::FillZ(Ptr() + oldSize, WordsToBytes(newSize-oldSize));
+		}
+	}
+
+void TInteger::CleanResizeL(TUint aNewSize)
+	{
+	assert(IsHeapBased());
+	TUint newSize = RoundupSize(aNewSize);
+	TUint oldSize = Size();
+	if(newSize > oldSize)
+		{
+		CleanGrowL(aNewSize);
+		}
+	else if(newSize < oldSize)
+		{
+		TUint* oldPtr = Ptr();
+		//1) zero memory above newsize
+		Mem::FillZ(oldPtr+WordsToBytes(aNewSize),WordsToBytes(oldSize-newSize));
+		//2) ReAlloc cell.  Since our newsize is less than oldsize, it is
+		//guarenteed not to move.  Thus this is just freeing part of our old
+		//cell to the heap for other uses.
+		SetPtr((TUint*)User::ReAllocL(Ptr(), WordsToBytes(newSize)));
+		SetSize(newSize);
+		}
+	}
+
+TInteger::TInteger() : iSize(0), iPtr(0)
+	{
+	}
+
+void TInteger::Construct(const TDesC8& aValue)
+	{
+	assert(Size() >= BytesToWords(aValue.Size()));
+	if(aValue.Size() > 0)
+		{
+		//People write numbers with the most significant digits first (big
+		//endian) but we store our numbers in little endian.  Hence we need to
+		//reverse the string by bytes.
+
+		TUint bytes = aValue.Size();
+		TUint8* i = (TUint8*)Ptr();
+		TUint8* j = (TUint8*)aValue.Ptr() + bytes;
+
+		//Swap the endianess of the number itself
+		// (msb) 01 02 03 04 05 06 (lsb) becomes ->
+		// (lsb) 06 05 04 03 02 01 (msb)
+		while( j != (TUint8*)aValue.Ptr() )
+			{
+			*i++ = *--j;
+			}
+		Mem::FillZ((TUint8*)Ptr() + bytes, WordsToBytes(Size()) - bytes);
+		}
+	else
+		{
+		//if size is zero, we zero the whole register
+		Mem::FillZ((TUint8*)Ptr(), WordsToBytes(Size()));
+		}
+	SetSign(EPositive);
+	}
+
+void TInteger::Construct(const TInteger& aInteger)
+	{
+	assert(Size() >= aInteger.Size());
+	CopyWords(Ptr(), aInteger.Ptr(), aInteger.Size());
+	if(Size() > aInteger.Size())
+		{
+		Mem::FillZ(Ptr()+aInteger.Size(), WordsToBytes(Size()-aInteger.Size()));
+		}
+	SetSign(aInteger.Sign());
+	}
+
+void TInteger::Construct(TInt aInteger)
+	{
+	Construct((TUint)aInteger);
+	if(aInteger < 0)
+		{
+		SetSign(ENegative);
+		Ptr()[0] = -aInteger;
+		}
+	}
+
+void TInteger::Construct(TUint aInteger)
+	{
+	assert(Size() >= 2);
+	SetSign(EPositive);
+	Ptr()[0] = aInteger;
+	Mem::FillZ(Ptr()+1, WordsToBytes(Size()-1));
+	}
+
+void TInteger::ConstructStack(TUint aWords, TUint aInteger)
+	{
+	SetPtr((TUint*)(this)+2);
+	//SetStackBased(); //Not strictly needed as stackbased is a 0 at bit 1
+	SetSize(aWords);
+	assert(Size() >= 2);
+	Ptr()[0] = aInteger;
+	Mem::FillZ(&(Ptr()[1]), WordsToBytes(Size()-1));
+	}
+
+void TInteger::ConstructStack(TUint aWords, const TInteger& aInteger)
+	{
+	SetPtr((TUint*)(this)+2);
+	//SetStackBased(); //Not strictly needed as stackbased is a 0 at bit 1
+	SetSize(aWords);
+	assert( Size() >= RoundupSize(aInteger.WordCount()) );
+	CopyWords(Ptr(), aInteger.Ptr(), aInteger.Size());
+	Mem::FillZ(Ptr()+aInteger.Size(), WordsToBytes(Size()-aInteger.Size()));
+	}
+