ID.hpp

#pragma once
 
#include <cstdint>
#include <limits>
 
namespace PixelBullet
{
    class ID
    {
    public:
        using ValueType = uint32_t;
 
        static constexpr uint32_t IndexBits = 24;
        static constexpr uint32_t VersionBits = 8;
        static constexpr ValueType IndexMask = (1u << IndexBits) - 1;
        static constexpr ValueType VersionMask = (1u << VersionBits) - 1;
 
        constexpr ID() noexcept
            : m_Value(Invalid().m_Value)
        {
        }
        constexpr ID(uint32_t index, uint32_t version) noexcept
            : m_Value((version << IndexBits) | (index & IndexMask))
        {
        }
 
        static constexpr ID Invalid() noexcept
        {
            return ID(std::numeric_limits<ValueType>::max());
        }
 
        static constexpr ID FromRaw(ValueType raw) noexcept
        {
            return ID(raw);
        }
 
        [[nodiscard]] constexpr uint32_t Index() const noexcept
        {
            return m_Value & IndexMask;
        }
 
        [[nodiscard]] constexpr uint32_t Version() const noexcept
        {
            return (m_Value >> IndexBits) & VersionMask;
        }
 
        [[nodiscard]] constexpr ValueType Raw() const noexcept
        {
            return m_Value;
        }
 
        constexpr bool operator==(const ID& other) const noexcept = default;
        constexpr bool operator!=(const ID& other) const noexcept = default;
 
        constexpr explicit operator bool() const noexcept
        {
            return m_Value != Invalid().m_Value;
        }
 
    private:
        explicit constexpr ID(ValueType raw) noexcept
            : m_Value(raw)
        {
        }
        ValueType m_Value;
    };
} // namespace PixelBullet