/// <summary>
/// Returns a type which is able to represent either of two given types without loss of precision
/// </summary>
/// <param name="td1">first given type</param>
/// <param name="td2">second given type</param>
/// <returns></returns>
private static TypeDescriptor GetCommonType(TypeDescriptor td1, TypeDescriptor td2)
{
if (td1.Equals(td2))
return td1;
if (IsSFix(td1) && IsUFix(td2))
{
var fmt1 = SFix.GetFormat(td1);
var fmt2 = UFix.GetFormat(td2);
return SFix.MakeType(
Math.Max(fmt1.IntWidth, fmt2.IntWidth + 1),
Math.Max(fmt1.FracWidth, fmt2.FracWidth));
}
else if (IsUFix(td1) && IsSFix(td2))
{
return GetCommonType(td2, td1);
}
else if (IsSFix(td1) && IsSFix(td2))
{
var fmt1 = SFix.GetFormat(td1);
var fmt2 = SFix.GetFormat(td2);
return SFix.MakeType(
Math.Max(fmt1.IntWidth, fmt2.IntWidth),
Math.Max(fmt1.FracWidth, fmt2.FracWidth));
}
else if (IsUFix(td1) && IsUFix(td2))
{
var fmt1 = UFix.GetFormat(td1);
var fmt2 = UFix.GetFormat(td2);
return UFix.MakeType(
Math.Max(fmt1.IntWidth, fmt2.IntWidth),
Math.Max(fmt1.FracWidth, fmt2.FracWidth));
}
else if (IsSigned(td1))
{
var fmt = SFix.GetFormat(td1);
var td1x = SFix.MakeType(fmt.IntWidth, fmt.FracWidth);
return GetCommonType(td1x, td2);
}
else if (IsSigned(td2))
{
return GetCommonType(td2, td1);
}
else if (IsUnsigned(td1))
{
var fmt = UFix.GetFormat(td1);
var td1x = UFix.MakeType(fmt.IntWidth, fmt.FracWidth);
return GetCommonType(td1x, td2);
}
else if (IsUnsigned(td2))
{
return GetCommonType(td2, td1);
}
else
{
throw new NotSupportedException(
"Cannot determine common type between " +
td1.ToString() + " and " + td2.ToString());
}
}