DwmFFIVar.hh

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//===========================================================================
// @(#) $DwmPath$
//===========================================================================
//  Copyright (c) Daniel W. McRobb 2012, 2023
//  All rights reserved.
//
//  Redistribution and use in source and binary forms, with or without
//  modification, are permitted provided that the following conditions
//  are met:
//
//  1. Redistributions of source code must retain the above copyright
//     notice, this list of conditions and the following disclaimer.
//  2. Redistributions in binary form must reproduce the above copyright
//     notice, this list of conditions and the following disclaimer in the
//     documentation and/or other materials provided with the distribution.
//  3. The names of the authors and copyright holders may not be used to
//     endorse or promote products derived from this software without
//     specific prior written permission.
//
//  IN NO EVENT SHALL DANIEL W. MCROBB BE LIABLE TO ANY PARTY FOR
//  DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES,
//  INCLUDING LOST PROFITS, ARISING OUT OF THE USE OF THIS SOFTWARE,
//  EVEN IF DANIEL W. MCROBB HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH
//  DAMAGE.
//
//  THE SOFTWARE PROVIDED HEREIN IS ON AN "AS IS" BASIS, AND
//  DANIEL W. MCROBB HAS NO OBLIGATION TO PROVIDE MAINTENANCE, SUPPORT,
//  UPDATES, ENHANCEMENTS, OR MODIFICATIONS. DANIEL W. MCROBB MAKES NO
//  REPRESENTATIONS AND EXTENDS NO WARRANTIES OF ANY KIND, EITHER
//  IMPLIED OR EXPRESS, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
//  WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE,
//  OR THAT THE USE OF THIS SOFTWARE WILL NOT INFRINGE ANY PATENT,
//  TRADEMARK OR OTHER RIGHTS.
//===========================================================================
 
//---------------------------------------------------------------------------
//---------------------------------------------------------------------------
 
#ifndef _DWMFFIVAR_HH_
#define _DWMFFIVAR_HH_
 
#include <cassert>
#include <type_traits>
 
namespace Dwm {
 
  //--------------------------------------------------------------------------
  //--------------------------------------------------------------------------
  
  //==========================================================================
 
  //--------------------------------------------------------------------------
  //--------------------------------------------------------------------------
  template<class T, class Enable = void>
  class FFIVar {};
 
  //--------------------------------------------------------------------------
  //--------------------------------------------------------------------------
  template <typename T>
  class FFIVar<T,typename std::enable_if<std::is_integral<T>::value>::type>
  {
  public:
    //------------------------------------------------------------------------
    //------------------------------------------------------------------------
    FFIVar()
        :  _value(0), _invertedValue((T)(~(T)0))
    { }
 
    //------------------------------------------------------------------------
    //------------------------------------------------------------------------
    ~FFIVar()
    {
      _value = 0;
      _invertedValue = 0;
    }
 
    //------------------------------------------------------------------------
    //------------------------------------------------------------------------
    FFIVar(const FFIVar & v) = default;
 
    //------------------------------------------------------------------------
    //------------------------------------------------------------------------
    FFIVar(const T & t)
        : _value(t), _invertedValue(~_value)
    {}
  
    //------------------------------------------------------------------------
    //------------------------------------------------------------------------
    FFIVar(FFIVar && v) = default;
 
    //------------------------------------------------------------------------
    //------------------------------------------------------------------------
    FFIVar(T && t)
        : _value(t), _invertedValue(~_value)
    {}
  
    //------------------------------------------------------------------------
    //------------------------------------------------------------------------
    FFIVar & operator = (const FFIVar & v) = default;
 
    //------------------------------------------------------------------------
    //------------------------------------------------------------------------
    FFIVar & operator = (const T & t)
    {
      _value = t;
      _invertedValue = ~_value;
      return *this;
    }
 
    //------------------------------------------------------------------------
    //------------------------------------------------------------------------
    FFIVar & operator = (FFIVar &&) = default;
 
    //------------------------------------------------------------------------
    //------------------------------------------------------------------------
    FFIVar & operator = (T && t)
    {
      _value = t;
      _invertedValue = ~_value;
      return *this;
    }
 
    //------------------------------------------------------------------------
    //------------------------------------------------------------------------
    operator T() const
    {
      assert(IsFFI());
      return _value;
    }
 
    //------------------------------------------------------------------------
    //------------------------------------------------------------------------
    bool operator <= (const FFIVar & v) const
    {
      assert(IsFFI() & v.IsFFI());
      return (_value <= v._value);
    }
 
    //------------------------------------------------------------------------
    //------------------------------------------------------------------------
    bool operator >= (const FFIVar & v) const
    {
      assert(IsFFI() & v.IsFFI());
      return (_value >= v._value);
    }
 
    //------------------------------------------------------------------------
    //------------------------------------------------------------------------
    bool operator < (const FFIVar & v) const
    {
      assert(IsFFI() & v.IsFFI());
      return (! (_value >= v._value));
    }
 
    //------------------------------------------------------------------------
    //------------------------------------------------------------------------
    bool operator > (const FFIVar & v) const
    {
      assert(IsFFI() & v.IsFFI());
      return (! (_value <= v._value));
    }
    
    //------------------------------------------------------------------------
    //------------------------------------------------------------------------
    template <typename IT>
    requires std::is_integral<IT>::value
    bool operator == (const IT & it) const
    {
      assert(IsFFI());
      return (it == _value);
    }
  
    //------------------------------------------------------------------------
    //------------------------------------------------------------------------
    bool operator == (const FFIVar & v) const
    {
      assert(v.IsFFI() && IsFFI());
      return(_value == v._value);
    }
 
    //------------------------------------------------------------------------
    //------------------------------------------------------------------------
    FFIVar operator ++ (int)
    {
      assert(IsFFI());
      T  rc = *this;
      ++_value;
      _invertedValue = ~_value;
      return rc;
    }
 
    //------------------------------------------------------------------------
    //------------------------------------------------------------------------
    FFIVar & operator ++ ()
    {
      assert(IsFFI());
      ++_value;
      _invertedValue = ~_value;
      return *this;
    }
 
    //------------------------------------------------------------------------
    //------------------------------------------------------------------------
    FFIVar operator -- (int)
    {
      assert(IsFFI());
      T  rc = *this;
      --_value;
      _invertedValue = ~_value;
      return rc;
    }
 
    //------------------------------------------------------------------------
    //------------------------------------------------------------------------
    FFIVar & operator -- ()
    {
      assert(IsFFI());
      --_value;
      _invertedValue = ~_value;
      return *this;
    }
 
    //------------------------------------------------------------------------
    //------------------------------------------------------------------------
    FFIVar & operator += (const FFIVar & v)
    {
      assert(v.IsFFI());
      _value += v._value;
      _invertedValue = ~_value;
      return *this;
    }
 
    //------------------------------------------------------------------------
    //------------------------------------------------------------------------
    FFIVar & operator -= (const FFIVar & v)
    {
      assert(v.IsFFI());
      _value -= v._value;
      _invertedValue = ~_value;
      return *this;
    }
 
    //------------------------------------------------------------------------
    //------------------------------------------------------------------------
    FFIVar & operator *= (const FFIVar & v)
    {
      assert(v.IsFFI());
      _value *= v._value;
      _invertedValue = ~_value;
      return *this;
    }
 
    //------------------------------------------------------------------------
    //------------------------------------------------------------------------
    FFIVar & operator /= (const FFIVar & v)
    {
      assert(v.IsFFI());
      assert(v._value);
      _value /= v._value;
      _invertedValue = ~_value;
      return *this;
    }
 
    //------------------------------------------------------------------------
    //------------------------------------------------------------------------
    FFIVar & operator %= (const FFIVar & v)
    {
      assert(v.IsFFI());
      assert(v._value);
      _value %= v._value;
      _invertedValue = ~_value;
      return *this;
    }
    
    //------------------------------------------------------------------------
    //------------------------------------------------------------------------
    FFIVar & operator >>= (const FFIVar & v)
    {
      assert(v.IsFFI());
      assert(v._value <= (sizeof(T) * 8));
      _value >>= v._value;
      _invertedValue = ~_value;
      return *this;
    }
 
    //------------------------------------------------------------------------
    //------------------------------------------------------------------------
    FFIVar & operator <<= (const FFIVar & v)
    {
      assert(v.IsFFI());
      assert(v._value <= (sizeof(T) * 8));
      _value <<= v._value;
      _invertedValue = ~_value;
      return *this;
    }
 
    //------------------------------------------------------------------------
    //------------------------------------------------------------------------
    FFIVar & operator &= (const FFIVar & v)
    {
      assert(v.IsFFI());
      _value &= v._value;
      _invertedValue = ~_value;
      return *this;
    }
 
    //------------------------------------------------------------------------
    //------------------------------------------------------------------------
    FFIVar & operator |= (const FFIVar & v)
    {
      assert(v.IsFFI());
      _value |= v._value;
      _invertedValue = ~_value;
      return *this;
    }
 
    //------------------------------------------------------------------------
    //------------------------------------------------------------------------
    FFIVar & operator ^= (const FFIVar & v)
    {
      assert(v.IsFFI());
      _value ^= v._value;
      _invertedValue = ~_value;
      return *this;
    }
 
    //------------------------------------------------------------------------
    //------------------------------------------------------------------------
    FFIVar operator ~ () const
    {
      return(FFIVar(~_value));
    }
    
    //------------------------------------------------------------------------
    //------------------------------------------------------------------------
    bool IsFFI() const
    {
      return (_value == (T)~(_invertedValue));
    }
 
  private:
    T  _value;
    T  _invertedValue;
  };
 
  //==========================================================================
 
  //--------------------------------------------------------------------------
  //--------------------------------------------------------------------------
  template <typename T>
  class FFIVar<T,typename std::enable_if<std::is_floating_point<T>::value>::type>
  {
  public:
    //------------------------------------------------------------------------
    //------------------------------------------------------------------------
    FFIVar()
        :  _value(0), _copiedValue(0)
    { }
 
    //------------------------------------------------------------------------
    //------------------------------------------------------------------------
    ~FFIVar()
    {
      _value = 0;
      _copiedValue = 1;
    }
 
    //------------------------------------------------------------------------
    //------------------------------------------------------------------------
    FFIVar(const FFIVar & v) = default;
 
    //------------------------------------------------------------------------
    //------------------------------------------------------------------------
    FFIVar(const T & t)
        : _value(t), _copiedValue(t)
    {}
  
    //------------------------------------------------------------------------
    //------------------------------------------------------------------------
    FFIVar(FFIVar && v) = default;
 
    //------------------------------------------------------------------------
    //------------------------------------------------------------------------
    FFIVar(T && t)
        : _value(t), _copiedValue(_value)
    {}
  
    //------------------------------------------------------------------------
    //------------------------------------------------------------------------
    FFIVar & operator = (const FFIVar & v) = default;
 
    //------------------------------------------------------------------------
    //------------------------------------------------------------------------
    FFIVar & operator = (const T & t)
    {
      _value = t;
      _copiedValue = _value;
      return *this;
    }
 
    //------------------------------------------------------------------------
    //------------------------------------------------------------------------
    FFIVar & operator = (FFIVar &&) = default;
 
    //------------------------------------------------------------------------
    //------------------------------------------------------------------------
    FFIVar & operator = (T && t)
    {
      _value = t;
      _copiedValue = _value;
      return *this;
    }
 
    //------------------------------------------------------------------------
    //------------------------------------------------------------------------
    operator T() const
    {
      assert(IsFFI());
      return _value;
    }
 
    //------------------------------------------------------------------------
    //------------------------------------------------------------------------
    bool operator <= (const FFIVar & v) const
    {
      assert(IsFFI() & v.IsFFI());
      return (_value <= v._value);
    }
 
    //------------------------------------------------------------------------
    //------------------------------------------------------------------------
    bool operator >= (const FFIVar & v) const
    {
      assert(IsFFI() & v.IsFFI());
      return (_value >= v._value);
    }
 
    //------------------------------------------------------------------------
    //------------------------------------------------------------------------
    bool operator < (const FFIVar & v) const
    {
      assert(IsFFI() & v.IsFFI());
      return (! (_value >= v._value));
    }
 
    //------------------------------------------------------------------------
    //------------------------------------------------------------------------
    bool operator > (const FFIVar & v) const
    {
      assert(IsFFI() & v.IsFFI());
      return (! (_value <= v._value));
    }
    
    //------------------------------------------------------------------------
    //------------------------------------------------------------------------
    template <typename IT>
    bool operator == (const IT & it) const
    {
      assert(IsFFI());
      return (it == _value);
    }
  
    //------------------------------------------------------------------------
    //------------------------------------------------------------------------
    bool operator == (const FFIVar & v) const
    {
      assert(v.IsFFI() && IsFFI());
      return(_value == v._value);
    }
 
    //------------------------------------------------------------------------
    //------------------------------------------------------------------------
    FFIVar & operator += (const FFIVar & v)
    {
      assert(v.IsFFI());
      _value += v._value;
      _copiedValue = _value;
      return *this;
    }
 
    //------------------------------------------------------------------------
    //------------------------------------------------------------------------
    FFIVar & operator -= (const FFIVar & v)
    {
      assert(v.IsFFI());
      _value -= v._value;
      _copiedValue = _value;
      return *this;
    }
 
    //------------------------------------------------------------------------
    //------------------------------------------------------------------------
    FFIVar & operator *= (const FFIVar & v)
    {
      assert(v.IsFFI());
      _value *= v._value;
      _copiedValue = _value;
      return *this;
    }
 
    //------------------------------------------------------------------------
    //------------------------------------------------------------------------
    FFIVar & operator /= (const FFIVar & v)
    {
      assert(v.IsFFI());
      assert(v._value);
      _value /= v._value;
      _copiedValue = _value;
      return *this;
    }
 
    //------------------------------------------------------------------------
    //------------------------------------------------------------------------
    bool IsFFI() const
    {
      return (_value == _copiedValue);
    }
 
  private:
    T  _value;
    T  _copiedValue;
  };
 
  //==========================================================================
 
  //--------------------------------------------------------------------------
  //--------------------------------------------------------------------------
  template <typename T>
  class FFIVar<T,typename std::enable_if<std::is_pointer<T>::value>::type>
  {
  public:
    //------------------------------------------------------------------------
    //------------------------------------------------------------------------
    FFIVar()
        :  _value(nullptr)
    {
      SetFlippedValue();
    }
 
    //------------------------------------------------------------------------
    //------------------------------------------------------------------------
    ~FFIVar()
    {
      _value = nullptr;
      _flippedValue = nullptr;
    }
 
    //------------------------------------------------------------------------
    //------------------------------------------------------------------------
    FFIVar(const FFIVar & v) = default;
 
    //------------------------------------------------------------------------
    //------------------------------------------------------------------------
    FFIVar(const T & t)
        : _value(t)
    {
      SetFlippedValue();
    }
  
    //------------------------------------------------------------------------
    //------------------------------------------------------------------------
    FFIVar(FFIVar && v) = default;
 
    //------------------------------------------------------------------------
    //------------------------------------------------------------------------
    FFIVar(T && t)
        : _value(t)
    {
      SetFlippedValue();
    }
  
    //------------------------------------------------------------------------
    //------------------------------------------------------------------------
    FFIVar & operator = (const FFIVar & v) = default;
 
    //------------------------------------------------------------------------
    //------------------------------------------------------------------------
    FFIVar & operator = (const T & t)
    {
      _value = t;
      SetFlippedValue();
      return *this;
    }
 
    //------------------------------------------------------------------------
    //------------------------------------------------------------------------
    FFIVar & operator = (FFIVar &&) = default;
 
    //------------------------------------------------------------------------
    //------------------------------------------------------------------------
    FFIVar & operator = (T && t)
    {
      _value = t;
      SetFlippedValue();
      return *this;
    }
 
    //------------------------------------------------------------------------
    //------------------------------------------------------------------------
    operator T() const
    {
      assert(IsFFI());
      return _value;
    }
 
    //------------------------------------------------------------------------
    //------------------------------------------------------------------------
    template <typename IT>
    bool operator == (const IT & it) const
    {
      assert(IsFFI());
      return (it == _value);
    }
  
    //------------------------------------------------------------------------
    //------------------------------------------------------------------------
    bool operator == (const FFIVar & v) const
    {
      assert(v.IsFFI() && IsFFI());
      return(_value == v._value);
    }
 
    //------------------------------------------------------------------------
    //------------------------------------------------------------------------
    FFIVar operator ++ (int)
    {
      assert(IsFFI());
      T  rc = *this;
      ++_value;
      SetFlippedValue();
      return rc;
    }
 
    //------------------------------------------------------------------------
    //------------------------------------------------------------------------
    FFIVar & operator ++ ()
    {
      assert(IsFFI());
      ++_value;
      SetFlippedValue();
      return *this;
    }
 
    //------------------------------------------------------------------------
    //------------------------------------------------------------------------
    FFIVar operator -- (int)
    {
      assert(IsFFI());
      T  rc = *this;
      --_value;
      SetFlippedValue();
      return rc;
    }
 
    //------------------------------------------------------------------------
    //------------------------------------------------------------------------
    FFIVar & operator -- ()
    {
      assert(IsFFI());
      --_value;
      SetFlippedValue();
      return *this;
    }
  
    //------------------------------------------------------------------------
    //------------------------------------------------------------------------
    FFIVar & operator += (const FFIVar & v)
    {
      assert(v.IsFFI());
      _value += v._value;
      SetFlippedValue();
      return *this;
    }
 
    //------------------------------------------------------------------------
    //------------------------------------------------------------------------
    FFIVar & operator -= (const FFIVar & v)
    {
      assert(v.IsFFI());
      _value -= v._value;
      SetFlippedValue();
      return *this;
    }
 
    //------------------------------------------------------------------------
    //------------------------------------------------------------------------
    bool IsFFI() const
    {
      static_assert(sizeof(T) == sizeof(size_t));
      const size_t  *pv = (const size_t *)&_value;
      const size_t  *pf = (const size_t *)&_flippedValue;
      return (*pf == (size_t)~(*pv));
    }
  
  private:
    T    _value;
    T    _flippedValue;
 
    //------------------------------------------------------------------------
    //------------------------------------------------------------------------
    void SetFlippedValue()
    {
      static_assert(sizeof(T) == sizeof(size_t));
      const size_t  *ps = (const size_t *)&_value;
      size_t        *pd = (size_t *)&_flippedValue;
      *pd = ~(*ps);
      return;
    }
  };
 
  //==========================================================================
  //==========================================================================
  
  //--------------------------------------------------------------------------
  //--------------------------------------------------------------------------
  template <typename T1, typename T2>
  concept AreFFI_Addable = requires(T1 a, T2 b) {
    { a + b } -> std::same_as<T1>;
  };
 
  //--------------------------------------------------------------------------
  //--------------------------------------------------------------------------
  template <typename T1, typename T2>
  concept AreFFI_Subtractable = requires(T1 a, T2 b) {
    { a - b } -> std::same_as<T1>;
  };
 
  //--------------------------------------------------------------------------
  //--------------------------------------------------------------------------
  template <typename T1, typename T2>
  concept AreFFI_Dividable = requires(T1 a, T2 b) {
    { a / b } -> std::same_as<T1>;
  };
 
  //--------------------------------------------------------------------------
  //--------------------------------------------------------------------------
  template <typename T1, typename T2>
  concept AreFFI_Moduloable = requires(T1 a, T2 b) {
    { a % b } -> std::same_as<T1>;
  };
 
  //--------------------------------------------------------------------------
  //--------------------------------------------------------------------------
  template <typename T1, typename T2>
  concept AreFFI_Multipliable = requires(T1 a, T2 b) {
    { a * b } -> std::same_as<T1>;
  };
  
  //==========================================================================
  //==========================================================================
  
  //--------------------------------------------------------------------------
  //--------------------------------------------------------------------------
  template <typename T1, typename T2,
            typename std::enable_if<AreFFI_Addable<T1,T2>>>
  FFIVar<T1> operator + (FFIVar<T1> lhs, FFIVar<T2> rhs)
  { lhs += rhs;  return lhs; }
 
  //--------------------------------------------------------------------------
  //--------------------------------------------------------------------------
  template <typename T1, typename T2,
            typename std::enable_if<AreFFI_Subtractable<T1,T2>>>
  FFIVar<T1> operator - (FFIVar<T1> lhs, FFIVar<T2> rhs)
  { lhs -= rhs;  return lhs; }
 
  //--------------------------------------------------------------------------
  //--------------------------------------------------------------------------
  template <typename T1, typename T2,
            typename std::enable_if<AreFFI_Multipliable<T1,T2>>>
  FFIVar<T1> operator * (FFIVar<T1> lhs, FFIVar<T2> rhs)
  { lhs *= rhs;  return lhs; }
 
  //--------------------------------------------------------------------------
  //--------------------------------------------------------------------------
  template <typename T1, typename T2,
            typename std::enable_if<AreFFI_Dividable<T1,T2>>>
  FFIVar<T1> operator / (FFIVar<T1> lhs, FFIVar<T2> rhs)
  { lhs /= rhs;  return lhs; }
 
  //--------------------------------------------------------------------------
  //--------------------------------------------------------------------------
  template <typename T1, typename T2,
            typename std::enable_if<AreFFI_Moduloable<T1,T2>>>
  FFIVar<T1> operator % (FFIVar<T1> lhs, FFIVar<T2> rhs)
  { lhs %= rhs;  return lhs; }
 
  //--------------------------------------------------------------------------
  //--------------------------------------------------------------------------
  template <typename T,
            typename std::enable_if<std::is_integral<T>::value>::type>
  FFIVar<T> operator >> (FFIVar<T> lhs, FFIVar<T> rhs)
  { lhs >>= rhs;  return lhs; }
 
  //--------------------------------------------------------------------------
  //--------------------------------------------------------------------------
  template <typename T,
            typename std::enable_if<std::is_integral<T>::value>::type>
  FFIVar<T> operator << (FFIVar<T> lhs, FFIVar<T> rhs)
  { lhs <<= rhs;  return lhs; }
 
  //--------------------------------------------------------------------------
  //--------------------------------------------------------------------------
  template <typename T,
            typename std::enable_if<std::is_integral<T>::value>::type>
  FFIVar<T> operator & (FFIVar<T> lhs, FFIVar<T> rhs)
  { lhs &= rhs;  return lhs; }
 
  //--------------------------------------------------------------------------
  //--------------------------------------------------------------------------
  template <typename T,
            typename std::enable_if<std::is_integral<T>::value>::type>
  FFIVar<T> operator | (FFIVar<T> lhs, FFIVar<T> rhs)
  { lhs |= rhs;  return lhs; }
 
  //--------------------------------------------------------------------------
  //--------------------------------------------------------------------------
  template <typename T,
            typename std::enable_if<std::is_integral<T>::value>::type>
  FFIVar<T> operator ^ (FFIVar<T> lhs, FFIVar<T> rhs)
  { lhs ^= rhs;  return lhs; }
  
 
}  // namespace Dwm
 
#endif  // _DWMFFIVAR_HH_