Iterator for query results without entity information. More...

#include <query.hpp>

Inheritance diagram for helios::ecs::details::QueryIterator< Components >:

Public Types
using	ComponentsType = std::conditional_t< AllComponentsConst< Components... >, const details::Components, details::Components >
	Components manager type based on whether all components are const-qualified.

using	iterator_category = std::forward_iterator_tag

using	value_type = std::tuple< ComponentAccessType< Components >... >

using	difference_type = ptrdiff_t

using	pointer = value_type *

using	reference = value_type

Public Member Functions
	QueryIterator (std::span< const std::reference_wrapper< const Archetype > > archetypes, ComponentsType &components, size_t archetype_index=0, size_t entity_index=0)
	Constructs iterator for query results.

	QueryIterator (const QueryIterator &) noexcept=default

	QueryIterator (QueryIterator &&) noexcept=default

	~QueryIterator () noexcept=default

QueryIterator &	operator= (const QueryIterator &) noexcept=default

QueryIterator &	operator= (QueryIterator &&) noexcept=default

QueryIterator &	operator++ ()
	Advances iterator to next matching entity.

QueryIterator	operator++ (int)
	Advances iterator to next matching entity.

QueryIterator &	operator-- ()
	Moves iterator to previous matching entity.

QueryIterator	operator-- (int)
	Moves iterator to previous matching entity.

value_type	operator* () const
	Dereferences iterator to get component tuple.

bool	operator== (const QueryIterator &other) const noexcept
	Compares iterators for equality.

bool	operator!= (const QueryIterator &other) const noexcept
	Compares iterators for inequality.

QueryIterator	begin () const noexcept
	Returns iterator to the beginning.

QueryIterator	end () const noexcept
	Returns iterator to the end.

Detailed Description

template<ComponentTrait... Components>
requires utils::UniqueTypes<Components...>
class helios::ecs::details::QueryIterator< Components >

Iterator for query results without entity information.

Provides forward iteration over entities matching the query criteria, returning tuples of requested component references. Supports const-qualified component access for read-only operations.

Note: Not thread-safe.

Template Parameters

Components Requested component access types (may include const qualifiers)

Definition at line 129 of file query.hpp.

Member Typedef Documentation

◆ ComponentsType

template<ComponentTrait... Components>

using helios::ecs::details::QueryIterator< Components >::ComponentsType = std::conditional_t<AllComponentsConst<Components...>, const details::Components, details::Components>

Components manager type based on whether all components are const-qualified.

Examples: /home/runner/work/HeliosEngine/HeliosEngine/src/core/include/helios/core/ecs/query.hpp.

Definition at line 132 of file query.hpp.

◆ difference_type

template<ComponentTrait... Components>

using helios::ecs::details::QueryIterator< Components >::difference_type = ptrdiff_t

Examples: /home/runner/work/HeliosEngine/HeliosEngine/src/core/include/helios/core/ecs/query.hpp.

Definition at line 138 of file query.hpp.

◆ iterator_category

template<ComponentTrait... Components>

using helios::ecs::details::QueryIterator< Components >::iterator_category = std::forward_iterator_tag

Examples: /home/runner/work/HeliosEngine/HeliosEngine/src/core/include/helios/core/ecs/query.hpp.

Definition at line 136 of file query.hpp.

◆ pointer

template<ComponentTrait... Components>

using helios::ecs::details::QueryIterator< Components >::pointer = value_type*

Examples: /home/runner/work/HeliosEngine/HeliosEngine/src/core/include/helios/core/ecs/query.hpp.

Definition at line 139 of file query.hpp.

◆ reference

template<ComponentTrait... Components>

using helios::ecs::details::QueryIterator< Components >::reference = value_type

Examples: /home/runner/work/HeliosEngine/HeliosEngine/src/core/include/helios/core/ecs/query.hpp.

Definition at line 140 of file query.hpp.

◆ value_type

template<ComponentTrait... Components>

using helios::ecs::details::QueryIterator< Components >::value_type = std::tuple<ComponentAccessType<Components>...>

Examples: /home/runner/work/HeliosEngine/HeliosEngine/src/core/include/helios/core/ecs/query.hpp.

Definition at line 137 of file query.hpp.

Constructor & Destructor Documentation

◆ QueryIterator() [1/3]

template<ComponentTrait... Components>
requires utils::UniqueTypes<Components...>

helios::ecs::details::QueryIterator< Components >::QueryIterator	(	std::span< const std::reference_wrapper< const Archetype > >	archetypes,
		ComponentsType &	components,
		size_t	archetype_index = `0`,
		size_t	entity_index = `0`
	)

Constructs iterator for query results.

Initializes iterator to point to the first matching entity.

Parameters

archetypes	Span of archetypes matching the query
components	Component manager for accessing component data
archetype_index	Starting archetype index (default: 0)
entity_index	Starting entity index within archetype (default: 0)

Examples: /home/runner/work/HeliosEngine/HeliosEngine/src/core/include/helios/core/ecs/query.hpp.

Definition at line 362 of file query.hpp.

    : archetypes_(archetypes), components_(components), archetype_index_(archetype_index), entity_index_(entity_index) {
  AdvanceToValidEntity();
}

◆ QueryIterator() [2/3]

template<ComponentTrait... Components>

helios::ecs::details::QueryIterator< Components >::QueryIterator ( const QueryIterator< Components > & )

defaultnoexcept

◆ QueryIterator() [3/3]

template<ComponentTrait... Components>

helios::ecs::details::QueryIterator< Components >::QueryIterator ( QueryIterator< Components > && )

defaultnoexcept

◆ ~QueryIterator()

template<ComponentTrait... Components>

helios::ecs::details::QueryIterator< Components >::~QueryIterator ( )

defaultnoexcept

Examples: /home/runner/work/HeliosEngine/HeliosEngine/src/core/include/helios/core/ecs/query.hpp.

Member Function Documentation

◆ begin()

template<ComponentTrait... Components>

QueryIterator helios::ecs::details::QueryIterator< Components >::begin ( ) const

inlinenoexcept

Returns iterator to the beginning.

Returns: Copy of this iterator

Examples: /home/runner/work/HeliosEngine/HeliosEngine/src/core/include/helios/core/ecs/query.hpp.

Definition at line 213 of file query.hpp.

213{ return *this; }

◆ end()

template<ComponentTrait... Components>

QueryIterator helios::ecs::details::QueryIterator< Components >::end ( ) const

inlinenoexcept

Returns iterator to the end.

Returns: End iterator

Examples: /home/runner/work/HeliosEngine/HeliosEngine/src/core/include/helios/core/ecs/query.hpp.

Definition at line 219 of file query.hpp.

219{ return {archetypes_, components_.get(), archetypes_.size(), 0}; }

◆ operator!=()

template<ComponentTrait... Components>

bool helios::ecs::details::QueryIterator< Components >::operator!= ( const QueryIterator< Components > & other ) const

inlinenoexcept

Compares iterators for inequality.

Parameters

other Iterator to compare with

Returns: True if iterators are not equal, false otherwise

Examples: /home/runner/work/HeliosEngine/HeliosEngine/src/core/include/helios/core/ecs/query.hpp.

Definition at line 207 of file query.hpp.

207{ return !(*this == other); }

◆ operator*()

template<ComponentTrait... Components>
requires utils::UniqueTypes<Components...>

auto helios::ecs::details::QueryIterator< Components >::operator* ( ) const

inline

Dereferences iterator to get component tuple.

Returns tuple of component references for the current entity. Handles const-qualified access appropriately.

Warning: Triggers assertion if iterator is at end or in invalid state.

Returns: Tuple of component references with appropriate const qualifiers

Examples: /home/runner/work/HeliosEngine/HeliosEngine/src/core/include/helios/core/ecs/query.hpp.

Definition at line 422 of file query.hpp.

                                                                        {
  HELIOS_ASSERT(!IsAtEnd(), "Cannot dereference end iterator!");
  HELIOS_ASSERT(archetype_index_ < archetypes_.size(), "Archetype index out of bounds!");
  HELIOS_ASSERT(entity_index_ < archetypes_[archetype_index_].get().Entities().size(), "Entity index out of bounds!");
 
  const auto& archetype = archetypes_[archetype_index_].get();
  const Entity entity = archetype.Entities()[entity_index_];
 
  return {[&]<typename ComponentType = ComponentTypeExtractor_t<Components>>() -> ComponentAccessType<Components> {
    return static_cast<ComponentAccessType<Components>>(components_.get().template GetComponent<ComponentType>(entity));
  }()...};
}

◆ operator++() [1/2]

template<ComponentTrait... Components>
requires utils::UniqueTypes<Components...>

auto helios::ecs::details::QueryIterator< Components >::operator++ ( )

inline

Advances iterator to next matching entity.

Returns: Reference to this iterator after advancement

Examples: /home/runner/work/HeliosEngine/HeliosEngine/src/core/include/helios/core/ecs/query.hpp.

Definition at line 370 of file query.hpp.

                                                                       {
  ++entity_index_;
  AdvanceToValidEntity();
  return *this;
}

◆ operator++() [2/2]

template<ComponentTrait... Components>
requires utils::UniqueTypes<Components...>

auto helios::ecs::details::QueryIterator< Components >::operator++ ( int )

inline

Advances iterator to next matching entity.

Returns: Copy of iterator before advancement

Definition at line 378 of file query.hpp.

                                                                         {
  auto copy = *this;
  ++(*this);
  return copy;
}

◆ operator--() [1/2]

template<ComponentTrait... Components>
requires utils::UniqueTypes<Components...>

auto helios::ecs::details::QueryIterator< Components >::operator-- ( )

inline

Moves iterator to previous matching entity.

Returns: Reference to this iterator after moving backward

Examples: /home/runner/work/HeliosEngine/HeliosEngine/src/core/include/helios/core/ecs/query.hpp.

Definition at line 386 of file query.hpp.

                                                                       {
  // If at end or beginning of current archetype, need to go back
  while (true) {
    if (entity_index_ > 0) {
      --entity_index_;
      return *this;
    }
 
    // Need to move to previous archetype
    if (archetype_index_ == 0) {
      // Already at beginning, can't go back further
      return *this;
    }
 
    --archetype_index_;
    // Move to last entity in previous archetype
    if (archetype_index_ < archetypes_.size()) {
      entity_index_ = archetypes_[archetype_index_].get().EntityCount();
      if (entity_index_ > 0) {
        --entity_index_;
        return *this;
      }
    }
  }
}

◆ operator--() [2/2]

template<ComponentTrait... Components>
requires utils::UniqueTypes<Components...>

auto helios::ecs::details::QueryIterator< Components >::operator-- ( int )

inline

Moves iterator to previous matching entity.

Returns: Copy of iterator before moving backward

Definition at line 414 of file query.hpp.

                                                                         {
  auto copy = *this;
  --(*this);
  return copy;
}

◆ operator=() [1/2]

template<ComponentTrait... Components>

QueryIterator & helios::ecs::details::QueryIterator< Components >::operator= ( const QueryIterator< Components > & )

defaultnoexcept

Examples: /home/runner/work/HeliosEngine/HeliosEngine/src/core/include/helios/core/ecs/query.hpp.

◆ operator=() [2/2]

template<ComponentTrait... Components>

QueryIterator & helios::ecs::details::QueryIterator< Components >::operator= ( QueryIterator< Components > && )

defaultnoexcept

◆ operator==()

template<ComponentTrait... Components>

bool helios::ecs::details::QueryIterator< Components >::operator== ( const QueryIterator< Components > & other ) const

inlinenoexcept

Compares iterators for equality.

Two iterators are equal if they point to the same archetype and entity indices.

Parameters

other Iterator to compare with

Returns: True if iterators are equal, false otherwise

Examples: /home/runner/work/HeliosEngine/HeliosEngine/src/core/include/helios/core/ecs/query.hpp.

Definition at line 198 of file query.hpp.

                                                                           {
    return archetype_index_ == other.archetype_index_ && entity_index_ == other.entity_index_;
  }

	Helios Engine 0.1.0 A modular ECS based data-oriented C++23 game engine

Public Types

Public Member Functions

Detailed Description

Member Typedef Documentation

◆ ComponentsType

◆ difference_type

◆ iterator_category

◆ pointer

◆ reference

◆ value_type

Constructor & Destructor Documentation

◆ QueryIterator() [1/3]

◆ QueryIterator() [2/3]

◆ QueryIterator() [3/3]

◆ ~QueryIterator()

Member Function Documentation

◆ begin()

◆ end()

◆ operator!=()

◆ operator*()

◆ operator++() [1/2]

◆ operator++() [2/2]

◆ operator--() [1/2]

◆ operator--() [2/2]

◆ operator=() [1/2]

◆ operator=() [2/2]

◆ operator==()