protected internal override BigNum Ceiling()
{
// using the identity ceil(x) == -floor(-x)
BigFloat floored = (BigFloat)Negate().Floor();
return(floored.Negate());
}
private static BigFloat Subtract(BigFloat a, BigFloat b, Boolean normalise)
{
a.Normalise();
b.Normalise();
a = (BigFloat)a.Clone();
b = (BigFloat)b.Clone();
if (a.IsZero && b.IsZero)
{
return(a);
}
if (a.Sign && !b.Sign)
{
b._sign = true;
return(Add(a, b, normalise));
}
if (!a.Sign && b.Sign)
{
a._sign = true;
BigFloat added = Add(a, b, normalise);
return((BigFloat)added.Negate());
}
BigFloat result = new BigFloat();
a.AlignExponent(b);
b.AlignExponent(a);
result._exp = a._exp;
Boolean wasSwapped = false;
if (b.Length > a.Length) // then switch them around
{
BigFloat temp = a;
a = b;
b = temp;
wasSwapped = true;
}
else
{
// if same length, check magnitude
BigFloat a1 = (BigFloat)a.Absolute();
BigFloat b1 = (BigFloat)b.Absolute();
if (a1 < b1)
{
BigFloat temp = a;
a = b;
b = temp;
wasSwapped = true;
}
else if (!(a1 > b1)) // i.e. equal
{
return(new BigFloat()); // return zero
}
}
// Do work
// it's a sad day when the preparation for an operation is just as long as the operation itself
SByte digit = 0;
SByte take = 0;
for (int i = 0; i < b.Length; i++)
{
digit = (SByte)(a[i] - b[i] - take);
if (digit < 0)
{
take = 1;
digit = (SByte)(10 + digit);
}
else
{
take = 0;
}
result._data.Add(digit);
}
for (int i = b.Length; i < a.Length; i++)
{
digit = (SByte)(a[i] - take);
if (digit < 0)
{
take = 1;
digit = (SByte)(10 + digit);
}
else
{
take = 0;
}
result._data.Add(digit);
}
result._sign = a.Sign && b.Sign ? !wasSwapped : wasSwapped;
/* if(normalise)
* result.Normalise(); */
return(result);
}