bithelper.h

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#pragma once

#include "datatypes.h"
#include <climits>
#include <limits>
#include <type_traits>

BEGIN_NAMESPACE_DATATYPES

class BitHelper
{
public:
    template <typename T = uint32_t, typename UT = typename std::make_unsigned<T>::type>
    constexpr static UT lsbMask(int N);

    template <typename T = uint32_t, typename UT = typename std::make_unsigned<T>::type>
    constexpr static UT lsbInvMask(int N);

    template <typename T = uint32_t, typename UT = typename std::make_unsigned<T>::type>
    constexpr static UT msbMask(int N);

    template <typename T = uint32_t, typename UT = typename std::make_unsigned<T>::type>
    constexpr static UT msbInvMask(int N);

    template <typename T>
    constexpr static T reverseBitOrder(T N);
};

template <typename T, typename UT>
constexpr UT BitHelper::lsbMask(int N)
{
    using SignedSize = std::make_signed_t<std::size_t>;

    if (((SignedSize) sizeof(UT) * 8) <= N)
        return (std::numeric_limits<UT>::max)();

    return UT(~((std::numeric_limits<UT>::max)() << N));
}

template <typename T, typename UT>
constexpr UT BitHelper::lsbInvMask(int N)
{
    return ~lsbMask<T, UT>(N);
}

template <typename T, typename UT>
constexpr UT BitHelper::msbMask(int N)
{
    using SignedSize = std::make_signed_t<std::size_t>;

    if (((SignedSize) sizeof(UT) * 8) <= N)
        return (std::numeric_limits<UT>::max)();

    return UT(~((std::numeric_limits<UT>::max)() >> N));
}

template <typename T, typename UT>
constexpr UT BitHelper::msbInvMask(int N)
{
    return ~msbMask<T, UT>(N);
}

template <typename T>
constexpr T BitHelper::reverseBitOrder(T N)
{
    T reverseValue = 0;
    int numberOfBits = sizeof(N) * CHAR_BIT;
    for (int i = 0; i < numberOfBits; i++)
    {
        reverseValue = (reverseValue << 1) | (N & 1);
        N >>= 1;
    }
    return reverseValue;
}

END_NAMESPACE_DATATYPES