helios::ecs::ConsumableMessageReader< T > Class Template Reference

Type-safe, zero-copy reader for consumable messages with consume support. More...

#include <reader.hpp>

Inheritance diagram for helios::ecs::ConsumableMessageReader< T >:

Public Types
using	value_type = ConsumableMessageWrapper<T>
using	size_type = MessageManager::size_type
using	const_iterator = ConsumableMessageWrapperIter<T>
using	iterator = const_iterator
Public Types inherited from helios::ecs::MessageReaderBase< ConsumableMessageReader< T >, T, ConsumableMessageWrapperIter< T > >
using	value_type
using	size_type
using	iterator
using	const_iterator

Public Member Functions
constexpr	ConsumableMessageReader (std::span< const T > previous, std::span< const T > current, ConsumedMessagesRegistry<> &consumed_registry) noexcept
	Constructs a ConsumableMessageReader from explicit spans and a consumed registry.
constexpr	ConsumableMessageReader (const MessageManager &manager, ConsumedMessagesRegistry<> &consumed_registry) noexcept
	Constructs a ConsumableMessageReader from the message manager and a per-system consumed registry.
	ConsumableMessageReader (ConsumableMessageReader &)=delete
constexpr	ConsumableMessageReader (ConsumableMessageReader &&) noexcept=default
constexpr	~ConsumableMessageReader () noexcept=default
ConsumableMessageReader &	operator= (ConsumableMessageReader &)=delete
constexpr ConsumableMessageReader &	operator= (ConsumableMessageReader &&) noexcept=default
constexpr void	ConsumeAll () const
	Marks all messages as consumed.
template<typename Pred> requires std::predicate<Pred, const T&>
constexpr size_type	ConsumeIf (const Pred &predicate) const
	Marks all messages matching a predicate as consumed.
constexpr auto	PreviousMessages () const noexcept -> std::span< const T >
	Gets the messages from the previous frame.
constexpr auto	CurrentMessages () const noexcept -> std::span< const T >
	Gets the messages from the current frame.
constexpr const_iterator	begin () const noexcept
	Returns a const iterator to the first message in the combined view.
constexpr const_iterator	end () const noexcept
	Returns a const iterator past the last message in the combined view.
template<typename Pred> requires std::predicate<Pred, const T&>
constexpr auto	ConsumeIf (const Pred &predicate) const -> size_type
Public Member Functions inherited from helios::ecs::MessageReaderBase< ConsumableMessageReader< T >, T, ConsumableMessageWrapperIter< T > >
constexpr	MessageReaderBase () noexcept=default
constexpr	~MessageReaderBase () noexcept=default
MessageReaderBase &	operator= (const MessageReaderBase &)=delete
constexpr void	ForEach (const Action &action) const
	Applies an action to every message (unwrapped const T&).
constexpr auto	Collect () const -> std::vector< T >
	Collects all messages (previous + current) into a vector of raw T values.
constexpr auto	CollectWith (const Alloc &alloc) const -> std::vector< T, Alloc >
	Collects all messages into a vector of raw T values using a custom allocator.
constexpr void	ReadInto (OutIt out) const
	Reads all messages into an output iterator.
constexpr auto	Filter (Pred predicate) const noexcept(noexcept(GetDerived().begin().Filter(std::move(predicate)))) -> utils::FilterAdapter< iterator, Pred >
	Returns a lazy filter adapter over the wrapped message sequence.
constexpr auto	Map (Func transform) const noexcept(noexcept(GetDerived().begin().Map(std::move(transform)))) -> utils::MapAdapter< iterator, Func >
	Returns a lazy map adapter over the wrapped message sequence.
constexpr auto	Take (size_t count) const noexcept(noexcept(GetDerived().begin().Take(count))) -> utils::TakeAdapter< iterator >
	Returns a lazy adapter yielding at most count wrappers.
constexpr auto	Skip (size_t count) const noexcept(noexcept(GetDerived().begin().Skip(count))) -> utils::SkipAdapter< iterator >
	Returns a lazy adapter that skips the first count wrappers.
constexpr auto	TakeWhile (Pred predicate) const noexcept(noexcept(GetDerived().begin().TakeWhile(std::move(predicate)))) -> utils::TakeWhileAdapter< iterator, Pred >
	Returns a lazy adapter that yields wrappers while predicate is true.
constexpr auto	SkipWhile (Pred predicate) const noexcept(noexcept(GetDerived().begin().SkipWhile(std::move(predicate)))) -> utils::SkipWhileAdapter< iterator, Pred >
	Returns a lazy adapter that skips wrappers while predicate is true.
constexpr auto	Enumerate () const noexcept(noexcept(GetDerived().begin().Enumerate())) -> utils::EnumerateAdapter< iterator >
	Returns a lazy adapter that pairs each wrapper with its zero-based index.
constexpr auto	Inspect (Func inspector) const noexcept(noexcept(GetDerived().begin().Inspect(std::move(inspector)))) -> utils::InspectAdapter< iterator, Func >
	Returns a lazy adapter that calls inspector on each wrapper as a side-effect.
constexpr auto	StepBy (size_t step) const noexcept(noexcept(GetDerived().begin().StepBy(step))) -> utils::StepByAdapter< iterator >
	Returns a lazy adapter that yields every step-th wrapper.
constexpr auto	Chain (Iter first, Iter last) const noexcept(noexcept(GetDerived().begin().Chain(std::move(first), std::move(last)))) -> utils::ChainAdapter< iterator, Iter >
	Returns a lazy adapter that chains another range of wrappers.
constexpr auto	Reverse () const noexcept(noexcept(GetDerived().begin().Reverse())) -> utils::ReverseAdapter< iterator >
	Returns a lazy adapter that yields wrappers in reverse order.
constexpr auto	Slide (size_t window_size) const noexcept(noexcept(GetDerived().begin().Slide(window_size))) -> utils::SlideAdapter< iterator >
	Returns a lazy adapter that yields windows of window_size wrappers.
constexpr auto	Stride (size_t stride) const noexcept(noexcept(GetDerived().begin().Stride(stride))) -> utils::StrideAdapter< iterator >
	Returns a lazy adapter that yields every stride-th wrapper.
constexpr auto	Zip (Iter first, Iter last) const noexcept(noexcept(GetDerived().begin().Zip(std::move(first), std::move(last)))) -> utils::ZipAdapter< iterator, Iter >
	Returns a lazy adapter that yields pairs of wrappers from two ranges.
constexpr Acc	Fold (Acc init, const Folder &folder) const
	Left-folds all messages with an accumulator.
constexpr auto	Find (const Pred &predicate) const -> std::optional< value_type >
	Returns a pointer to the first message matching a predicate.
constexpr size_type	CountIf (const Pred &predicate) const
	Counts messages matching a predicate.
constexpr auto	Partition (const Pred &predicate) const -> std::pair< std::vector< value_type >, std::vector< value_type > >
	Partitions wrapped messages into matching and non-matching groups.
constexpr auto	MaxBy (const KeyFunc &key_func) const -> std::optional< value_type >
	Finds the wrapped message with the maximum extracted key.
constexpr auto	MinBy (const KeyFunc &key_func) const -> std::optional< value_type >
	Finds the wrapped message with the minimum extracted key.
constexpr auto	GroupBy (const KeyFunc &key_func) const -> std::unordered_map< std::decay_t< std::invoke_result_t< KeyFunc, const value_type & > >, std::vector< value_type > >
	Groups wrapped messages by a key extracted from each wrapper.
constexpr bool	Any (const Pred &predicate) const
	Checks if any message matches a predicate.
constexpr bool	All (const Pred &predicate) const
	Checks if all messages match a predicate.
constexpr bool	None (const Pred &predicate) const
	Checks if no messages match a predicate.
constexpr bool	Empty () const noexcept
	Checks if there are no messages.
constexpr size_type	Count () const noexcept
	Returns the total number of messages (previous + current).

Friends
class	MessageReaderBase< ConsumableMessageReader< T >, T, ConsumableMessageWrapperIter< T > >

Detailed Description

template<ConsumableMessageTrait T>
class helios::ecs::ConsumableMessageReader< T >

Type-safe, zero-copy reader for consumable messages with consume support.

Provides a read-only view over the combined (previous + current) message queues for a specific message type. Messages are accessed via spans directly into the underlying TypedBuffer storage — no copying is performed.

Consumed messages are not filtered during iteration within the same frame. They are removed at the next MessageManager::Update call.

Note

Thread-safe, but beware that ConsumableMessageWrapper's Consume() method is NOT thread-safe.

Template Parameters

T	Message type satisfying ConsumableMessageTrait

// Wrapper iteration — with consume support
for (auto wrapper : reader) {
  if ((*wrapper).priority > 5) {
    wrapper.Consume();
  }
}
 
// Lazy adapter chaining — operates on ConsumableMessageWrapper<T>
reader.Filter([](const auto& w) { return (*w).amount > 10; })
      .ForEach([](const auto& w) { w.Consume(); });
 
// Direct span access
auto prev = reader.PreviousMessages();
auto curr = reader.CurrentMessages();

Definition at line 875 of file reader.hpp.

Member Typedef Documentation

const_iterator

template<ConsumableMessageTrait T>

using helios::ecs::ConsumableMessageReader< T >::const_iterator = ConsumableMessageWrapperIter<T>

Definition at line 884 of file reader.hpp.

iterator

template<ConsumableMessageTrait T>

using helios::ecs::ConsumableMessageReader< T >::iterator = const_iterator

Definition at line 885 of file reader.hpp.

size_type

template<ConsumableMessageTrait T>

using helios::ecs::ConsumableMessageReader< T >::size_type = MessageManager::size_type

Definition at line 883 of file reader.hpp.

value_type

template<ConsumableMessageTrait T>

using helios::ecs::ConsumableMessageReader< T >::value_type = ConsumableMessageWrapper<T>

Definition at line 882 of file reader.hpp.

Constructor & Destructor Documentation

ConsumableMessageReader() [1/4]

template<ConsumableMessageTrait T>

helios::ecs::ConsumableMessageReader< T >::ConsumableMessageReader ( std::span< const T > previous, std::span< const T > current, ConsumedMessagesRegistry<> & consumed_registry )

inlineconstexprnoexcept

Constructs a ConsumableMessageReader from explicit spans and a consumed registry.

Parameters

previous	Span of messages from the previous frame
current	Span of messages from the current frame
consumed_registry	Mutable reference to the per-system consumed messages registry

Definition at line 895 of file reader.hpp.

ConsumableMessageReader() [2/4]

template<ConsumableMessageTrait T>

helios::ecs::ConsumableMessageReader< T >::ConsumableMessageReader ( const MessageManager & manager, ConsumedMessagesRegistry<> & consumed_registry )

inlineconstexprnoexcept

Constructs a ConsumableMessageReader from the message manager and a per-system consumed registry.

Parameters

manager	Const reference to the message manager
consumed_registry	Mutable reference to the per-system consumed messages registry

Definition at line 907 of file reader.hpp.

ConsumableMessageReader() [3/4]

template<ConsumableMessageTrait T>

helios::ecs::ConsumableMessageReader< T >::ConsumableMessageReader ( ConsumableMessageReader< T > & )

delete

ConsumableMessageReader() [4/4]

template<ConsumableMessageTrait T>

helios::ecs::ConsumableMessageReader< T >::ConsumableMessageReader ( ConsumableMessageReader< T > && )

constexprdefaultnoexcept

~ConsumableMessageReader()

template<ConsumableMessageTrait T>

helios::ecs::ConsumableMessageReader< T >::~ConsumableMessageReader ( )

constexprdefaultnoexcept

Member Function Documentation

begin()

template<ConsumableMessageTrait T>

const_iterator helios::ecs::ConsumableMessageReader< T >::begin ( ) const

inlinenodiscardconstexprnoexcept

Returns a const iterator to the first message in the combined view.

Returns

Const iterator to the beginning

Definition at line 958 of file reader.hpp.

ConsumeAll()

template<ConsumableMessageTrait T>

void helios::ecs::ConsumableMessageReader< T >::ConsumeAll ( ) const

constexpr

Marks all messages as consumed.

Definition at line 1024 of file reader.hpp.

ConsumeIf() [1/2]

template<ConsumableMessageTrait T>

template<typename Pred>
requires std::predicate<Pred, const T&>

size_type helios::ecs::ConsumableMessageReader< T >::ConsumeIf ( const Pred & predicate ) const

constexpr

Marks all messages matching a predicate as consumed.

Template Parameters

Pred	Predicate type (const T&) -> bool

Parameters

predicate

Predicate function

Returns

Number of messages marked as consumed

ConsumeIf() [2/2]

template<ConsumableMessageTrait T>

template<typename Pred>
requires std::predicate<Pred, const T&>

auto helios::ecs::ConsumableMessageReader< T >::ConsumeIf ( const Pred & predicate ) const -> size_type

constexpr

Definition at line 1035 of file reader.hpp.

CurrentMessages()

template<ConsumableMessageTrait T>

auto helios::ecs::ConsumableMessageReader< T >::CurrentMessages ( ) const -> std::span< const T >

inlinenodiscardconstexprnoexcept

Gets the messages from the current frame.

Returns

Span of const messages from the current queue

Definition at line 949 of file reader.hpp.

end()

template<ConsumableMessageTrait T>

const_iterator helios::ecs::ConsumableMessageReader< T >::end ( ) const

inlinenodiscardconstexprnoexcept

Returns a const iterator past the last message in the combined view.

Returns

Const iterator to the end

Definition at line 966 of file reader.hpp.

operator=() [1/2]

template<ConsumableMessageTrait T>

ConsumableMessageReader & helios::ecs::ConsumableMessageReader< T >::operator= ( ConsumableMessageReader< T > && )

constexprdefaultnoexcept

operator=() [2/2]

template<ConsumableMessageTrait T>

ConsumableMessageReader & helios::ecs::ConsumableMessageReader< T >::operator= ( ConsumableMessageReader< T > & )

delete

PreviousMessages()

template<ConsumableMessageTrait T>

auto helios::ecs::ConsumableMessageReader< T >::PreviousMessages ( ) const -> std::span< const T >

inlinenodiscardconstexprnoexcept

Gets the messages from the previous frame.

Returns

Span of const messages from the previous queue

Definition at line 940 of file reader.hpp.

Friends And Related Symbol Documentation

MessageReaderBase< ConsumableMessageReader< T >, T, ConsumableMessageWrapperIter< T > >

template<ConsumableMessageTrait T>

friend class MessageReaderBase< ConsumableMessageReader< T >, T, ConsumableMessageWrapperIter< T > >

friend

Definition at line 840 of file reader.hpp.