jh::pod::optional< T > Struct Template Reference

POD-compatible optional wrapper. More...

#include <jh/pods/optional.h>

Public Types
using	value_type = T
	Alias of contained type.

Public Member Functions
constexpr	optional () noexcept=default
	Default constructor (empty state).
void	store (const T &value) noexcept
	Store a value by copying raw memory.
void	clear () noexcept
	Clear the stored value (set to empty).
T *	get () noexcept
	Get mutable pointer to stored value.
const T *	get () const noexcept
	Get const pointer to stored value.
bool	has () const noexcept
	Whether a value is present.
bool	empty () const noexcept
	Whether the optional is empty.
T &	ref () noexcept
	Access stored value by reference.
const T &	ref () const noexcept
	Access stored value by const reference.
T	value_or (T fallback) const noexcept
	Return stored value or fallback.
constexpr bool	operator== (const optional &rhs) const noexcept
	Equality comparison with another optional.

Public Attributes
std::byte	storage [sizeof(T)]
	Raw storage; flattens type ABI, never access directly.
bool	has_value
	Presence flag (true = has value).

Detailed Description

template<cv_free_pod_like T>
struct jh::pod::optional< T >

POD-compatible optional wrapper.

Stores raw bytes for T and a boolean flag. Provides POD-level semantics similar to std::optional.

Equality Semantics:

• If one has value and the other not → false
• If both are empty → true (ignores raw storage)
• If both have value → compare storage bytes (memcmp)

Usage Model:

• Use .store() to assign
• Check .has() / .empty() before access
• Use .ref() / .get() to access value
• Use .value_or() for fallback

Template Parameters

T	Element type. Must satisfy pod_like<T> and be free of const/volatile qualifiers (i.e. satisfy cv_free_pod_like<T>). Using a cv-qualified type would make the optional itself non-POD due to loss of trivial assignment and standard layout guarantees.

Member Function Documentation

get() [1/2]

template<cv_free_pod_like T>

const T * jh::pod::optional< T >::get ( ) const

inlinenodiscardnoexcept

Get const pointer to stored value.

Returns

Pointer to const T, must check .has() before use.

get() [2/2]

template<cv_free_pod_like T>

T * jh::pod::optional< T >::get ( )

inlinenoexcept

Get mutable pointer to stored value.

Returns

Pointer to T, must check .has() before use.

operator==()

template<cv_free_pod_like T>

bool jh::pod::optional< T >::operator== ( const optional< T > & rhs ) const

inlineconstexprnoexcept

Equality comparison with another optional.

Semantics are aligned with std::optional:

• If one has a value and the other does not → false
• If both are empty → true
• If both have a value → compare the underlying storage bytes

Parameters

rhs	Other optional to compare with.

Returns

true if both optionals have the same state and (if present) identical raw byte content, false otherwise.

Note

This operator does not rely on = default, because the default comparison would also require raw storage equality when has_value == false. That would force meaningless zeroing of storage in .clear(). Instead, we define comparison explicitly: empty optionals are always equal regardless of storage content.

Raw comparison is performed with std::memcmp, ensuring POD-level semantics without invoking T::operator==.

ref() [1/2]

template<cv_free_pod_like T>

const T & jh::pod::optional< T >::ref ( ) const

inlinenodiscardnoexcept

Access stored value by const reference.

Returns

Const reference to T. Undefined if .has() == false.

ref() [2/2]

template<cv_free_pod_like T>

T & jh::pod::optional< T >::ref ( )

inlinenodiscardnoexcept

Access stored value by reference.

Returns

Reference to T. Undefined if .has() == false.

store()

template<cv_free_pod_like T>

void jh::pod::optional< T >::store ( const T & value )

inlinenoexcept

Store a value by copying raw memory.

Parameters

value

Source value to copy.

value_or()

template<cv_free_pod_like T>

T jh::pod::optional< T >::value_or ( T fallback ) const

inlinenodiscardnoexcept

Return stored value or fallback.

Parameters

fallback

Value to return if empty.

Returns

Copy of stored or fallback value.

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The documentation for this struct was generated from the following file:

• include/jh/pods/optional.h