text: /****************************************************************************
  Copyright (c) 2020 Simdsoft Limited.
  
   Purpose: Make bitmask operators could be use at different namespace.
  
   Permission is hereby granted, free of charge, to any person obtaining a copy
   of this software and associated documentation files (the "Software"), to deal
   in the Software without restriction, including without limitation the rights
   to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
   copies of the Software, and to permit persons to whom the Software is
   furnished to do so, subject to the following conditions:
  
   The above copyright notice and this permission notice shall be included in
   all copies or substantial portions of the Software.
  
   THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
   IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
   FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
   AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
   LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
   OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
   THE SOFTWARE.
   ****************************************************************************/
  #ifndef SIMDSOFT__BITMASK_HPP
  #define SIMDSOFT__BITMASK_HPP
  #pragma once
  
  #include <type_traits>
  
  #if !defined(_STD)
  #  define _STD ::std::
  #endif
  
  // BITMASK OPERATIONS, modified from msvc++ <type_traits> for cross-platform compiling.
  #define SIMDSOFT_ENABLE_BITMASK_OPS(_BITMASK)                                                      \
    constexpr _BITMASK operator&(_BITMASK _Left, _BITMASK _Right) noexcept                           \
    { /* return _Left & _Right */                                                                    \
      using _IntTy = _STD underlying_type<_BITMASK>::type;                                           \
      return static_cast<_BITMASK>(static_cast<_IntTy>(_Left) & static_cast<_IntTy>(_Right));        \
    }                                                                                                \
                                                                                                     \
    constexpr _BITMASK operator|(_BITMASK _Left, _BITMASK _Right) noexcept                           \
    { /* return _Left | _Right */                                                                    \
      using _IntTy = _STD underlying_type<_BITMASK>::type;                                           \
      return static_cast<_BITMASK>(static_cast<_IntTy>(_Left) | static_cast<_IntTy>(_Right));        \
    }                                                                                                \
                                                                                                     \
    constexpr _BITMASK operator^(_BITMASK _Left, _BITMASK _Right) noexcept                           \
    { /* return _Left ^ _Right */                                                                    \
      using _IntTy = _STD underlying_type<_BITMASK>::type;                                           \
      return static_cast<_BITMASK>(static_cast<_IntTy>(_Left) ^ static_cast<_IntTy>(_Right));        \
    }                                                                                                \
                                                                                                     \
    constexpr _BITMASK& operator&=(_BITMASK& _Left, _BITMASK _Right) noexcept                        \
    { /* return _Left &= _Right */                                                                   \
      return _Left = _Left & _Right;                                                                 \
    }                                                                                                \
                                                                                                     \
    constexpr _BITMASK& operator|=(_BITMASK& _Left, _BITMASK _Right) noexcept                        \
    { /* return _Left |= _Right */                                                                   \
      return _Left = _Left | _Right;                                                                 \
    }                                                                                                \
                                                                                                     \
    constexpr _BITMASK& operator^=(_BITMASK& _Left, _BITMASK _Right) noexcept                        \
    { /* return _Left ^= _Right */                                                                   \
      return _Left = _Left ^ _Right;                                                                 \
    }                                                                                                \
                                                                                                     \
    constexpr _BITMASK operator~(_BITMASK _Left) noexcept                                            \
    { /* return ~_Left */                                                                            \
      using _IntTy = _STD underlying_type<_BITMASK>::type;                                           \
      return static_cast<_BITMASK>(~static_cast<_IntTy>(_Left));                                     \
    }                                                                                                \
                                                                                                     \
    constexpr bool _Bitmask_includes(_BITMASK _Left, _BITMASK _Elements) noexcept                    \
    { /* return (_Left & _Elements) != _BITMASK{} */                                                 \
      return (_Left & _Elements) != _BITMASK{};                                                      \
    }                                                                                                \
                                                                                                     \
    constexpr bool _Bitmask_includes_all(_BITMASK _Left, _BITMASK _Elements) noexcept                \
    { /* return (_Left & _Elements) == _Elements */                                                  \
      return (_Left & _Elements) == _Elements;                                                       \
    }
  
  // BITSHIFT OPERATIONS, inspired from msvc++ <type_traits>.
  #define SIMDSOFT_ENABLE_BITSHIFT_OPS(_BITMASK)                                                     \
    constexpr _BITMASK operator>>(_BITMASK _Left, _BITMASK _Right) noexcept                          \
    { /* return _Left & _Right */                                                                    \
      using _IntTy = _STD underlying_type<_BITMASK>::type;                                           \
      return static_cast<_BITMASK>(static_cast<_IntTy>(_Left) >> static_cast<_IntTy>(_Right));       \
    }                                                                                                \
                                                                                                     \
    constexpr _BITMASK operator<<(_BITMASK _Left, _BITMASK _Right) noexcept                          \
    { /* return _Left & _Right */                                                                    \
      using _IntTy = _STD underlying_type<_BITMASK>::type;                                           \
      return static_cast<_BITMASK>(static_cast<_IntTy>(_Left) << static_cast<_IntTy>(_Right));       \
    }
  
  namespace bitmask
  {
  inline bool ispot(int v) { return (v > 0) && ((v & (v - 1)) == 0); }
  } // namespace bitmask
  
  #endif
  