IEquatable< Type > Class Template Reference

Allows Type to be hashable, use operator==, and use operator!=. More...

#include <IEquatable.hxx>

Collaboration diagram for IEquatable< Type >:

Public Member Functions
	IEquatable ()
	Create an Equatable type. More...
constexpr bool	operator!= (const IEquatable< Type > &other) const noexcept
bool	operator== (const IEquatable< Type > &other) const noexcept

Protected Member Functions
void	onHashChanged (std::size_t hash) noexcept
	Call when the hash has changed. More...
void	onHashChanged () noexcept
	Call when the hash has changed. More...

Private Attributes
std::size_t	m_Hash

Detailed Description

template<typename Type>
class IEquatable< Type >

Allows Type to be hashable, use operator==, and use operator!=.

First, Type should implement std::size_t Hash() const noexcept. Whenever your data is mutated, including at constructor-time, you must call onHashChanged(). If you are concerned with hash conflicts, then Type should implement bool Equals(const Type& other) const noexcept and operator== will also verify for strong equality. Otherwise, it will only compare hashes. This abstraction is especially efficient for compound types.

Template Parameters

Type	the data type that must be Equatable

Definition at line 28 of file IEquatable.hxx.

Constructor & Destructor Documentation

IEquatable()

template<typename Type >

IEquatable< Type >::IEquatable

Create an Equatable type.

Definition at line 2 of file IEquatable.inl.hxx.

{
  using FunctorType = typename GetMemberType<decltype(&Type::Hash)>::type;
  static_assert(std::is_same_v<FunctorType, std::size_t() const noexcept>,
                "You must implement std::size_t Hash() const noexcept and make it accessible to IEquatable");
}

Member Function Documentation

onHashChanged() [1/2]

template<typename Type >

void IEquatable< Type >::onHashChanged

protectednoexcept

Call when the hash has changed.

Definition at line 27 of file IEquatable.inl.hxx.

{ m_Hash = static_cast<Type &>(*this).Hash(); }

onHashChanged() [2/2]

template<typename Type >

void IEquatable< Type >::onHashChanged ( std::size_t  hash )

protectednoexcept

Call when the hash has changed.

Parameters

hash	the new hash

Definition at line 26 of file IEquatable.inl.hxx.

{ m_Hash = hash; }

operator!=()

template<typename Type >

constexpr bool IEquatable< Type >::operator!= ( const IEquatable< Type > &  other ) const

constexprnoexcept

Returns

true if not equal

Definition at line 9 of file IEquatable.inl.hxx.

{
  return m_Hash != other.m_Hash;
}

operator==()

template<typename Type >

bool IEquatable< Type >::operator== ( const IEquatable< Type > &  other ) const

noexcept

Returns

true if equal

Definition at line 14 of file IEquatable.inl.hxx.

{
  if constexpr (is_strong_equatable_type<Type>::value)
  {
    return m_Hash == other.m_Hash && Type::Equals(other);
  }
  else
  {
    return m_Hash == other.m_Hash;
  }
}

Member Data Documentation

m_Hash

template<typename Type >

std::size_t IEquatable< Type >::m_Hash

private

Definition at line 32 of file IEquatable.hxx.

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The documentation for this class was generated from the following files:

• src/util/IEquatable.hxx
• src/util/IEquatable.inl.hxx