// $Revision: 1.5 $

    // Copyright (C) 1994-1995 Taligent, Inc. All rights reserved.

#ifndef TaligentSamples_ADDITIONIMPLEMENTATION
#include "AdditionImplementation.h"
#endif

#ifndef _H_LIMITS
#include <limits.h>
#endif


//---- TAdditionImplementation -----------------------------------------------------------

TaligentTypeExtensionMacro(TAdditionImplementation)

TAdditionImplementation::TAdditionImplementation()
{
}

TAdditionImplementation::TAdditionImplementation(const TAdditionImplementation& source)
{
}

TAdditionImplementation::~TAdditionImplementation()
{
}

TAdditionImplementation&
TAdditionImplementation::operator=(const TAdditionImplementation& source)
{
    return *this;
}

TStream&
TAdditionImplementation::operator>>=(TStream& toStream) const
{
    short version(kOriginalVersion);
    version >>= toStream;
    return toStream;
}

TStream&
TAdditionImplementation::operator<<=(TStream& fromStream)
{
    short version;
    version <<= fromStream;
    return fromStream;
}

long
TAdditionImplementation::Add(long num1, long num2)
{
    TestForOverflowAndUnderflow(num1, num2);
    return num1 + num2;
}

void
TAdditionImplementation::AddOne(long& num)
{
    if (num == LONG_MAX) {
        throw TMathException(TMathException::kOverflow);
    }
    ++num;
}

void
TAdditionImplementation::TestForOverflowAndUnderflow(long num1, long num2)
{
    long absoluteValue = Abs(num1);
    long amountLeftUntilOverOrUnderflow = LONG_MAX - absoluteValue;
    
    if (num1 < 0 && num2 < 0) {         // Possible underflow
        if (Abs(num2) > amountLeftUntilOverOrUnderflow) {
            throw TMathException(TMathException::kUnderflow);
        }
    }
    else if (num1 > 0 && num2 > 0) {    // Possible overflow
        if (num2 > amountLeftUntilOverOrUnderflow) {
            throw TMathException(TMathException::kOverflow);
        }
    }
}