native_integer.h

// Description: Native integer type as a finite integer.

#ifndef PASTELSYS_NATIVE_INTEGER_H
#define PASTELSYS_NATIVE_INTEGER_H

// See concept.txt on why integer_concept.h must not
// be included here.
//#include "pastel/sys/integer/integer_concept.h"

#include "pastel/sys/real/scientific_notation_fwd.h"

#include <limits>
#include <climits>
#include <cmath>
#include <type_traits>

namespace Pastel
{

    // Integer

    template <typename Type>
    requires std::is_unsigned_v<Type>
    bool even(const Type& that)
    {
        return (that & 1) == 0;
    }

    template <typename Type>
    requires std::is_signed_v<Type>
    bool even(const Type& that)
    {
        // This should read the following, but I can not 
        // include twos_complement.h, because that would 
        // create a circular dependency.

        // return even(signedToTwosComplement(that));

        // This is the equivalent code.
        using Unsigned = typename std::make_unsigned<Type>::type;
        return even((Unsigned)that);
    }

    template <typename Type>
    requires std::is_integral_v<Type>
    bool odd(const Type& that)
    {
        return !even(that);
    }

    template <typename Type>
    requires std::is_integral_v<Type>
    ScientificNotation asScientific(const Type& that)
    {
        return ScientificNotation {negative(that), 0, abs(that)};
    }

}

#endif