Filtering processors

Description

Processors for filtering events.

Functions
template<typename GatedEventList, typename OpenEvent, typename CloseEvent, typename Downstream>
auto	tcspc::gate (arg::initially_open< bool > initially_open, Downstream downstream)
	Create a processor that gates events depending on current state.
template<typename EventList, typename Downstream>
auto	tcspc::select (Downstream downstream)
	Create a processor that passes a given set of events and discards others.
template<typename Downstream>
auto	tcspc::select_all (Downstream downstream)
	Create a processor that passes all events.
template<typename Downstream>
auto	tcspc::select_none (Downstream downstream)
	Create a processor that passes no events.
template<typename EventList, typename Downstream>
auto	tcspc::select_not (Downstream downstream)
	Create a processor that discards a given set of events and passes others.

Function Documentation

gate()

template<typename GatedEventList, typename OpenEvent, typename CloseEvent, typename Downstream>

auto tcspc::gate	(	arg::initially_open< bool >	initially_open,
		Downstream	downstream )

Create a processor that gates events depending on current state.

The processor keeps an internal boolean state: the gate. The initial state of the gate is determined by initially_open. When an OpenEvent is received, the gate is opened. When a CloseEvent is received, the gate is closed.

Events belonging to GatedEventList are gated: they are passed through if and only if the gate is currently open.

All events not in GatedEventList are passed through (including OpenEvent and CloseEvent).

Template Parameters

GatedEventList	event types to gate
OpenEvent	event type that opens the gate
CloseEvent	event type that closes the gate
Downstream	downstream processor type

Parameters

initially_open	whether the gate is open before the first OpenEvent or CloseEvent event is received
downstream	downstream processor

Returns

processor

Events handled

• OpenEvent: open the gate; pass through
• CloseEvent: close the gate; pass through
• Types in GatedEventList: pass through if gate open; otherwise no action
• All other types: pass through with no action
• Flush: pass through with no action

select()

template<typename EventList, typename Downstream>

auto tcspc::select

(

Downstream

downstream

)

Create a processor that passes a given set of events and discards others.

Template Parameters

EventList	event types to pass
Downstream	downstream processor type

Parameters

downstream

downstream processor

Returns

processor

Events handled

• Types in EventList: pass through with no action
• Types not in EventList: ignore
• Flush: pass through with no action

select_all()

template<typename Downstream>

auto tcspc::select_all

(

Downstream

downstream

)

Create a processor that passes all events.

In other words, this is a no-op processor.

Template Parameters

Downstream

downstream processor type

Parameters

downstream

downstream processor

Returns

processor

Events handled

• All types: pass through with no action
• Flush: pass through with no action

select_none()

template<typename Downstream>

auto tcspc::select_none

(

Downstream

downstream

)

Create a processor that passes no events.

The processor does pass end-of-stream, so can be used as a way to detect the end of the stream.

Template Parameters

Downstream

downstream processor type

Parameters

downstream

downstream processor

Returns

processor

Events handled

• All types: ignore
• Flush: pass through with no action

select_not()

template<typename EventList, typename Downstream>

auto tcspc::select_not

(

Downstream

downstream

)

Create a processor that discards a given set of events and passes others.

Template Parameters

EventList	event types to discard
Downstream	downstream processor type

Parameters

downstream

downstream processor

Returns

processor

Events handled

• Types in EventList: ignore
• Types not in EventList: pass through with no action
• Flush: pass through with no action