/// <summary>Returns a number that expresses this number minus
/// another.</summary>
/// <param name='b'>The second operand to the subtraction.</param>
/// <returns>A CBOR number that expresses this number minus the given
/// number.</returns>
/// <exception cref='ArgumentNullException'>The parameter <paramref
/// name='b'/> is null.</exception>
public CBORNumber Subtract(CBORNumber b)
{
if (b == null)
{
throw new ArgumentNullException(nameof(b));
}
CBORNumber a = this;
object objA = a.value;
object objB = b.value;
Kind typeA = a.kind;
Kind typeB = b.kind;
if (typeA == Kind.Integer && typeB == Kind.Integer)
{
var valueA = (long)objA;
var valueB = (long)objB;
if ((valueB < 0 && Int64.MaxValue + valueB < valueA) ||
(valueB > 0 && Int64.MinValue + valueB > valueA))
{
// would overflow, convert to EInteger
return(CBORNumber.FromObject(
EInteger.FromInt64(valueA).Subtract(EInteger.FromInt64(valueB))));
}
return(new CBORNumber(Kind.Integer, valueA - valueB));
}
if (typeA == Kind.ERational || typeB == Kind.ERational)
{
ERational e1 = GetNumberInterface(typeA).AsExtendedRational(objA);
ERational e2 = GetNumberInterface(typeB).AsExtendedRational(objB);
return(new CBORNumber(Kind.ERational, e1.Subtract(e2)));
}
if (typeA == Kind.EDecimal || typeB == Kind.EDecimal)
{
EDecimal e1 = GetNumberInterface(typeA).AsExtendedDecimal(objA);
EDecimal e2 = GetNumberInterface(typeB).AsExtendedDecimal(objB);
return(new CBORNumber(Kind.EDecimal, e1.Subtract(e2)));
}
if (typeA == Kind.EFloat || typeB == Kind.EFloat ||
typeA == Kind.Double || typeB == Kind.Double)
{
EFloat e1 = GetNumberInterface(typeA).AsExtendedFloat(objA);
EFloat e2 = GetNumberInterface(typeB).AsExtendedFloat(objB);
return(new CBORNumber(Kind.EFloat, e1.Subtract(e2)));
}
else
{
EInteger b1 = GetNumberInterface(typeA).AsEInteger(objA);
EInteger b2 = GetNumberInterface(typeB).AsEInteger(objB);
return(new CBORNumber(Kind.EInteger, b1 - (EInteger)b2));
}
}
public static CBORObject Subtract(CBORObject a, CBORObject b)
{
if (a == null)
{
throw new ArgumentNullException("a");
}
if (b == null)
{
throw new ArgumentNullException("b");
}
if (a.Type != CBORType.Number)
{
throw new ArgumentException("a.Type (" + a.Type +
") is not equal to " + CBORType.Number);
}
if (b.Type != CBORType.Number)
{
throw new ArgumentException("b.Type (" + b.Type +
") is not equal to " + CBORType.Number);
}
object objA = a.ThisItem;
object objB = b.ThisItem;
int typeA = a.ItemType;
int typeB = b.ItemType;
if (typeA == CBORObject.CBORObjectTypeInteger && typeB ==
CBORObject.CBORObjectTypeInteger)
{
var valueA = (long)objA;
var valueB = (long)objB;
if ((valueB < 0 && Int64.MaxValue + valueB < valueA) ||
(valueB > 0 && Int64.MinValue + valueB > valueA))
{
// would overflow, convert to EInteger
return(CBORObject.FromObject(((EInteger)valueA) -
(EInteger)valueB));
}
return(CBORObject.FromObject(valueA - valueB));
}
if (typeA == CBORObject.CBORObjectTypeExtendedRational ||
typeB == CBORObject.CBORObjectTypeExtendedRational)
{
ERational e1 =
CBORObject.GetNumberInterface(typeA).AsExtendedRational(objA);
ERational e2 =
CBORObject.GetNumberInterface(typeB).AsExtendedRational(objB);
return(CBORObject.FromObject(e1.Subtract(e2)));
}
if (typeA == CBORObject.CBORObjectTypeExtendedDecimal ||
typeB == CBORObject.CBORObjectTypeExtendedDecimal)
{
EDecimal e1 =
CBORObject.GetNumberInterface(typeA).AsExtendedDecimal(objA);
EDecimal e2 =
CBORObject.GetNumberInterface(typeB).AsExtendedDecimal(objB);
return(CBORObject.FromObject(e1.Subtract(e2)));
}
if (typeA == CBORObject.CBORObjectTypeExtendedFloat || typeB ==
CBORObject.CBORObjectTypeExtendedFloat ||
typeA == CBORObject.CBORObjectTypeDouble || typeB ==
CBORObject.CBORObjectTypeDouble ||
typeA == CBORObject.CBORObjectTypeSingle || typeB ==
CBORObject.CBORObjectTypeSingle)
{
EFloat e1 =
CBORObject.GetNumberInterface(typeA).AsExtendedFloat(objA);
EFloat e2 = CBORObject.GetNumberInterface(typeB).AsExtendedFloat(objB);
return(CBORObject.FromObject(e1.Subtract(e2)));
}
else
{
EInteger b1 = CBORObject.GetNumberInterface(typeA).AsEInteger(objA);
EInteger b2 = CBORObject.GetNumberInterface(typeB).AsEInteger(objB);
return(CBORObject.FromObject(b1 - (EInteger)b2));
}
}
