helios::utils::TakeAdapter< Iter > Class Template Reference

Iterator adapter that yields only the first N elements. More...

#include <functional_adapters.hpp>

Inheritance diagram for helios::utils::TakeAdapter< Iter >:

Public Types
using	iterator_concept = details::adapter_iterator_concept_t<Iter>
using	iterator_category = details::adapter_iterator_category_t<Iter>
using	value_type = std::iter_value_t<Iter>
using	reference = value_type
using	pointer = void
using	difference_type = std::iter_difference_t<Iter>

Public Member Functions
constexpr	TakeAdapter (Iter begin, Iter end, size_t count) noexcept(std::is_nothrow_move_constructible_v< Iter > &&std::is_nothrow_copy_constructible_v< Iter >)
	Constructs a take adapter with the given iterator range and count.
template<ExternalRange R> requires TakeAdapterRequirements<std::ranges::iterator_t<R>>
constexpr	TakeAdapter (R &range, size_t count) noexcept(noexcept(TakeAdapter(std::ranges::begin(range), std::ranges::end(range), count)))
	Constructs a take adapter from a range and count.
template<ExternalRange R> requires TakeAdapterRequirements<std::ranges::iterator_t<const R>>
constexpr	TakeAdapter (const R &range, size_t count) noexcept(noexcept(TakeAdapter(std::ranges::cbegin(range), std::ranges::cend(range), count)))
	Constructs a map adapter from a const range and count.
constexpr	TakeAdapter (const TakeAdapter &) noexcept(std::is_nothrow_copy_constructible_v< Iter >)=default
constexpr	TakeAdapter (TakeAdapter &&) noexcept(std::is_nothrow_move_constructible_v< Iter >)=default
constexpr	~TakeAdapter () noexcept(std::is_nothrow_destructible_v< Iter >)=default
constexpr TakeAdapter &	operator= (const TakeAdapter &) noexcept(std::is_nothrow_copy_assignable_v< Iter >)=default
constexpr TakeAdapter &	operator= (TakeAdapter &&) noexcept(std::is_nothrow_move_assignable_v< Iter >)=default
constexpr TakeAdapter &	operator++ () noexcept(noexcept(++std::declval< Iter & >()))
constexpr TakeAdapter	operator++ (int) noexcept(std::is_nothrow_copy_constructible_v< TakeAdapter > &&noexcept(++std::declval< TakeAdapter & >()))
constexpr reference	operator* () const noexcept(noexcept(*std::declval< const Iter & >()))
pointer	operator-> () const =delete
constexpr bool	operator== (const TakeAdapter &other) const noexcept(noexcept(std::declval< const Iter & >()==std::declval< const Iter & >()))
constexpr bool	operator!= (const TakeAdapter &other) const noexcept(noexcept(std::declval< const TakeAdapter & >()==std::declval< const TakeAdapter & >()))
constexpr bool	IsAtEnd () const noexcept(noexcept(std::declval< const Iter & >()==std::declval< const Iter & >()))
	Checks if the iterator has reached the end.
constexpr TakeAdapter	begin () const noexcept(std::is_nothrow_copy_constructible_v< TakeAdapter >)
constexpr TakeAdapter	end () const noexcept(std::is_nothrow_copy_constructible_v< TakeAdapter >)
Public Member Functions inherited from helios::utils::FunctionalAdapterBase< TakeAdapter< Iter > >
constexpr auto	Filter (Pred predicate) const noexcept(noexcept(FilterAdapter< TakeAdapter< Iter >, Pred >(GetDerived().begin(), GetDerived().end(), std::move(predicate))))
	Chains another filter operation on top of this iterator.
constexpr auto	Map (Func transform) const noexcept(noexcept(MapAdapter< TakeAdapter< Iter >, Func >(GetDerived().begin(), GetDerived().end(), std::move(transform))))
	Transforms each element using the given function.
constexpr auto	Take (size_t count) const noexcept(noexcept(TakeAdapter< Derived >(GetDerived().begin(), GetDerived().end(), count)))
	Limits the number of elements to at most count.
constexpr auto	Skip (size_t count) const noexcept(noexcept(SkipAdapter< TakeAdapter< Iter > >(GetDerived().begin(), GetDerived().end(), count)))
	Skips the first count elements.
constexpr auto	TakeWhile (Pred predicate) const noexcept(noexcept(TakeWhileAdapter< TakeAdapter< Iter >, Pred >(GetDerived().begin(), GetDerived().end(), std::move(predicate))))
	Takes elements while a predicate is true.
constexpr auto	SkipWhile (Pred predicate) const noexcept(noexcept(SkipWhileAdapter< TakeAdapter< Iter >, Pred >(GetDerived().begin(), GetDerived().end(), std::move(predicate))))
	Skips elements while a predicate is true.
constexpr auto	Enumerate () const noexcept(noexcept(EnumerateAdapter< TakeAdapter< Iter > >(GetDerived().begin(), GetDerived().end())))
	Adds an index to each element.
constexpr auto	Inspect (Func inspector) const noexcept(noexcept(InspectAdapter< TakeAdapter< Iter >, Func >(GetDerived().begin(), GetDerived().end(), std::move(inspector))))
	Observes each element without modifying it.
constexpr auto	StepBy (size_t step) const noexcept(noexcept(StepByAdapter< TakeAdapter< Iter > >(GetDerived().begin(), GetDerived().end(), step)))
	Takes every Nth element.
constexpr auto	Chain (OtherIter begin, OtherIter end) const noexcept(noexcept(ChainAdapter< TakeAdapter< Iter >, OtherIter >(GetDerived().begin(), GetDerived().end(), std::move(begin), std::move(end))))
	Chains another range after this one.
constexpr auto	Reverse () const noexcept(noexcept(ReverseAdapter< TakeAdapter< Iter > >(GetDerived().begin(), GetDerived().end())))
	Reverses the order of elements.
constexpr auto	Slide (size_t window_size) const noexcept(noexcept(SlideAdapter< TakeAdapter< Iter > >(GetDerived().begin(), GetDerived().end(), window_size)))
	Creates sliding windows over elements.
constexpr auto	Stride (size_t stride) const noexcept(noexcept(StrideAdapter< TakeAdapter< Iter > >(GetDerived().begin(), GetDerived().end(), stride)))
	Takes every Nth element with stride.
constexpr auto	Zip (OtherIter begin, OtherIter end) const noexcept(noexcept(ZipAdapter< TakeAdapter< Iter >, OtherIter >(GetDerived().begin(), GetDerived().end(), std::move(begin), std::move(end))))
	Zips another range with this one.
constexpr void	ForEach (const Action &action) const
	Terminal operation: applies an action to each element.
constexpr T	Fold (T init, const Folder &folder) const
	Terminal operation: reduces elements to a single value using a folder function.
constexpr auto	Find (const Pred &predicate) const
	Terminal operation: finds the first element satisfying a predicate.
constexpr size_t	CountIf (const Pred &predicate) const
	Terminal operation: counts elements satisfying a predicate.
constexpr auto	Partition (const Pred &predicate) const
	Terminal operation: partitions elements into two groups based on a predicate.
constexpr auto	PartitionWith (const Pred &predicate, Allocator allocator) const
	Terminal operation: partitions elements with a custom allocator.
constexpr auto	MaxBy (const KeyFunc &key_func) const
	Terminal operation: finds the element with the maximum value according to a key function.
constexpr auto	MinBy (const KeyFunc &key_func) const
	Terminal operation: finds the element with the minimum value according to a key function.
constexpr auto	GroupBy (const KeyFunc &key_func) const
	Terminal operation: groups elements by a key function.
constexpr auto	GroupByWith (const KeyFunc &key_func, MapAllocator map_allocator, ValueAllocator value_allocator) const
	Terminal operation: groups elements by key with custom allocators.
constexpr auto	Collect () const
	Terminal operation: collects all elements into a vector.
constexpr auto	CollectWith (Allocator allocator={}) const
	Terminal operation: collects all elements into a vector with a custom allocator.
constexpr void	Into (OutIt out) const
	Terminal operation: writes all elements into an output iterator.
constexpr bool	Any (const Pred &predicate) const
	Terminal operation: checks if any element satisfies a predicate.
constexpr bool	All (const Pred &predicate) const
	Terminal operation: checks if all elements satisfy a predicate.
constexpr bool	None (const Pred &predicate) const
	Terminal operation: checks if no elements satisfy a predicate.

Additional Inherited Members
Protected Member Functions inherited from helios::utils::FunctionalAdapterBase< TakeAdapter< Iter > >
constexpr TakeAdapter< Iter > &	GetDerived () noexcept
	Gets reference to derived class instance.

Detailed Description

template<typename Iter>
requires TakeAdapterRequirements<Iter>
class helios::utils::TakeAdapter< Iter >

Iterator adapter that yields only the first N elements.

This adapter limits the number of elements yielded by the underlying iterator to at most the specified count. Once the count is reached or the underlying iterator reaches its end, iteration stops.

Note

This adapter maintains forward iterator semantics.

The adapter is constexpr-compatible for compile-time evaluation.

Template Parameters

Iter	Underlying iterator type that satisfies IteratorLike concept

// Get only the first 5 entities
auto first_five = query.Take(5);

Definition at line 856 of file functional_adapters.hpp.

Member Typedef Documentation

difference_type

template<typename Iter>

using helios::utils::TakeAdapter< Iter >::difference_type = std::iter_difference_t<Iter>

Definition at line 863 of file functional_adapters.hpp.

iterator_category

template<typename Iter>

using helios::utils::TakeAdapter< Iter >::iterator_category = details::adapter_iterator_category_t<Iter>

Definition at line 859 of file functional_adapters.hpp.

iterator_concept

template<typename Iter>

using helios::utils::TakeAdapter< Iter >::iterator_concept = details::adapter_iterator_concept_t<Iter>

Definition at line 858 of file functional_adapters.hpp.

pointer

template<typename Iter>

using helios::utils::TakeAdapter< Iter >::pointer = void

Definition at line 862 of file functional_adapters.hpp.

reference

template<typename Iter>

using helios::utils::TakeAdapter< Iter >::reference = value_type

Definition at line 861 of file functional_adapters.hpp.

value_type

template<typename Iter>

using helios::utils::TakeAdapter< Iter >::value_type = std::iter_value_t<Iter>

Definition at line 860 of file functional_adapters.hpp.

Constructor & Destructor Documentation

TakeAdapter() [1/5]

template<typename Iter>

helios::utils::TakeAdapter< Iter >::TakeAdapter ( Iter begin, Iter end, size_t count )

inlineconstexprnoexcept

Constructs a take adapter with the given iterator range and count.

Parameters

begin	Start of the iterator range
end	End of the iterator range
count	Maximum number of elements to yield

Definition at line 871 of file functional_adapters.hpp.

TakeAdapter() [2/5]

template<typename Iter>

template<ExternalRange R>
requires TakeAdapterRequirements<std::ranges::iterator_t<R>>

helios::utils::TakeAdapter< Iter >::TakeAdapter ( R & range, size_t count )

inlineconstexprnoexcept

Constructs a take adapter from a range and count.

Template Parameters

R	The type of the input range

Parameters

range	The input range to adapt
count	The number of elements to take

Definition at line 888 of file functional_adapters.hpp.

TakeAdapter() [3/5]

template<typename Iter>

template<ExternalRange R>
requires TakeAdapterRequirements<std::ranges::iterator_t<const R>>

helios::utils::TakeAdapter< Iter >::TakeAdapter ( const R & range, size_t count )

inlineconstexprnoexcept

Constructs a map adapter from a const range and count.

Template Parameters

R	The type of the input range

Parameters

range	The input range to adapt
count	The number of elements to take

Definition at line 901 of file functional_adapters.hpp.

TakeAdapter() [4/5]

template<typename Iter>

helios::utils::TakeAdapter< Iter >::TakeAdapter ( const TakeAdapter< Iter > & ) const

constexprdefaultnoexcept

TakeAdapter() [5/5]

template<typename Iter>

helios::utils::TakeAdapter< Iter >::TakeAdapter ( TakeAdapter< Iter > && ) const

constexprdefaultnoexcept

~TakeAdapter()

template<typename Iter>

helios::utils::TakeAdapter< Iter >::~TakeAdapter ( )

constexprdefaultnoexcept

Member Function Documentation

begin()

template<typename Iter>

TakeAdapter helios::utils::TakeAdapter< Iter >::begin ( ) const

inlinenodiscardconstexprnoexcept

Definition at line 951 of file functional_adapters.hpp.

end()

template<typename Iter>
requires TakeAdapterRequirements<Iter>

auto helios::utils::TakeAdapter< Iter >::end ( ) const

nodiscardconstexprnoexcept

Definition at line 1014 of file functional_adapters.hpp.

IsAtEnd()

template<typename Iter>

bool helios::utils::TakeAdapter< Iter >::IsAtEnd ( ) const

inlinenodiscardconstexprnoexcept

Checks if the iterator has reached the end.

Returns

True if at end, false otherwise

Definition at line 945 of file functional_adapters.hpp.

operator!=()

template<typename Iter>

bool helios::utils::TakeAdapter< Iter >::operator!= ( const TakeAdapter< Iter > & other ) const

inlinenodiscardconstexprnoexcept

Definition at line 935 of file functional_adapters.hpp.

operator*()

template<typename Iter>

reference helios::utils::TakeAdapter< Iter >::operator* ( ) const

inlinenodiscardconstexprnoexcept

Definition at line 924 of file functional_adapters.hpp.

operator++() [1/2]

template<typename Iter>
requires TakeAdapterRequirements<Iter>

auto helios::utils::TakeAdapter< Iter >::operator++ ( )

constexprnoexcept

Definition at line 975 of file functional_adapters.hpp.

operator++() [2/2]

template<typename Iter>
requires TakeAdapterRequirements<Iter>

auto helios::utils::TakeAdapter< Iter >::operator++ ( int )

nodiscardconstexprnoexcept

Definition at line 986 of file functional_adapters.hpp.

operator->()

template<typename Iter>

pointer helios::utils::TakeAdapter< Iter >::operator-> ( ) const

delete

operator=() [1/2]

template<typename Iter>

TakeAdapter & helios::utils::TakeAdapter< Iter >::operator= ( const TakeAdapter< Iter > & )

constexprdefaultnoexcept

operator=() [2/2]

template<typename Iter>

TakeAdapter & helios::utils::TakeAdapter< Iter >::operator= ( TakeAdapter< Iter > && )

constexprdefaultnoexcept

operator==()

template<typename Iter>
requires TakeAdapterRequirements<Iter>

bool helios::utils::TakeAdapter< Iter >::operator== ( const TakeAdapter< Iter > & other ) const

nodiscardconstexprnoexcept

Definition at line 996 of file functional_adapters.hpp.