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AK: Add FixedPoint cast operator for up/downcasting to other sizes

This enables casting between different size FixedPoint variables or
constructing them from other sized FixedPoint values.
This commit is contained in:
Tom 2022-01-20 21:31:13 -07:00 committed by Linus Groh
parent 06fc72ca0c
commit c468a9cc2d
2 changed files with 61 additions and 0 deletions

View file

@ -20,6 +20,9 @@ class FixedPoint {
using This = FixedPoint<precision, Underlying>;
constexpr static Underlying radix_mask = (static_cast<Underlying>(1) << precision) - 1;
template<size_t P, typename U>
friend class FixedPoint;
public:
constexpr FixedPoint() = default;
template<Integral I>
@ -34,6 +37,12 @@ public:
{
}
template<size_t P, typename U>
explicit constexpr FixedPoint(FixedPoint<P, U> const& other)
: m_value(other.template cast_to<precision, Underlying>().m_value)
{
}
template<FloatingPoint F>
explicit ALWAYS_INLINE operator F() const
{
@ -304,7 +313,27 @@ public:
template<FloatingPoint F>
bool operator<=(F other) const { return *this <= (This)other; }
template<size_t P, typename U>
operator FixedPoint<P, U>() const
{
return cast_to<P, U>();
}
private:
template<size_t P, typename U>
constexpr FixedPoint<P, U> cast_to() const
{
U raw_value = static_cast<U>(m_value >> precision) << P;
if constexpr (precision > P)
raw_value |= (m_value & radix_mask) >> (precision - P);
else if constexpr (precision < P)
raw_value |= static_cast<U>(m_value & radix_mask) << (P - precision);
else
raw_value |= m_value & radix_mask;
return FixedPoint<P, U>::create_raw(raw_value);
}
static This create_raw(Underlying value)
{
This t {};