IterAdapter< POS, CON > Class Template Reference

#include "lib/iter-adapter.hpp"

Description

template<class POS, class CON>
class lib::IterAdapter< POS, CON >

Adapter for building an implementation of the »Lumiera Forward Iterator« concept.

The "current position" is represented as an opaque element (usually a nested iterator), with callbacks into the controlling container instance to manage this position. This allows to influence and customise the iteration process to a large extent. Basically such an IterAdapter behaves like the similar concept from STL, but

• it is not just a disguised pointer (meaning, it's more expensive)
• it checks validity on every operation and may throw
• it has a distinct back-link to the source container
• the source container needs to support checkPoint() and iterNext() free functions.
• we may need friendship to implement those extension points on the container
• the end-of-iteration can be detected by bool check

  Note

  it is possible to "hide" a smart-ptr within the CON template parameter.

  Template Parameters

  POS	pointer or similar mutable link to the current value. Will be bool() checked to detect iteration end, end else dereferenced.
  CON	type of the backing container, which needs to implement two extension point functions for iteration control

  Stipulations

• POS refers to the current position within the data source of this iterator.
  1. it should be default constructible
  2. it should be copy constructible
  3. when IterAdapter is supposed to be assignable, then POS should be
  4. it should provide embedded typedefs for pointer, reference and value_type, or alternatively resolve these types through specialisation of meta::ValueTypeBinding.
  5. it should be convertible to the pointer type it declares
  6. dereferencing should yield a type that is convertible to the reference type
• CON points to the data source of this iterator (typically a data container type) We store a pointer-like backlink to invoke a special iteration control API:
  1. checkPoint yields true iff the source has yet more result values to yield
  2. iterNext advances the POS to the next element

Note

• when POS is just a pointer, we use the pointee as value type
• but when POS is a class, we expect the usual STL style nested typedefs value_type, reference and pointer

See also

scoped-ptrvect.hpp usage example

value-type-binding.hpp

iter-adapter-test.cpp

Definition at line 207 of file iter-adapter.hpp.

Public Types
using	value_type = _ValTrait::value_type
using	reference = _ValTrait::reference
using	pointer = _ValTrait::pointer

Public Member Functions
	IterAdapter (CON src, POS const &startpos)
	IterAdapter ()
	operator bool () const
reference	operator* () const
pointer	operator-> () const
IterAdapter &	operator++ ()
bool	isValid () const
bool	empty () const
	ENABLE_USE_IN_STD_RANGE_FOR_LOOPS (IterAdapter)

Friends
template<class P1 , class P2 , class CX >
bool	operator== (IterAdapter< P1, CX > const &, IterAdapter< P2, CX > const &)
	comparison is allowed to access impl iterator

Protected Types
using	ConRef = meta::RefTraits< CON >::Reference

Protected Member Functions
bool	check () const
	ask the controlling container if this position is valid.
void	iterate ()
	ask the controlling container to yield the next position.
ConRef	source ()
	allow derived classes to access backing container
const ConRef	source () const
void	resetPos (POS otherPos)

Private Types
using	_ValTrait = meta::ValueTypeBinding< std::remove_pointer_t< POS > >

Private Member Functions
void	_maybe_throw () const

Private Attributes
CON	source_
POS	pos_

Constructor & Destructor Documentation

IterAdapter() [1/2]

template<class POS , class CON >

IterAdapter ( CON  src, POS const &  startpos  )

inline

Definition at line 220 of file iter-adapter.hpp.

References IterAdapter< POS, CON >::check().

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IterAdapter() [2/2]

template<class POS , class CON >

IterAdapter ( )

inline

Definition at line 227 of file iter-adapter.hpp.

Member Typedef Documentation

_ValTrait

template<class POS , class CON >

using _ValTrait = meta::ValueTypeBinding<std::remove_pointer_t<POS> >

private

Definition at line 212 of file iter-adapter.hpp.

value_type

template<class POS , class CON >

using value_type = _ValTrait::value_type

Definition at line 215 of file iter-adapter.hpp.

reference

template<class POS , class CON >

using reference = _ValTrait::reference

Definition at line 216 of file iter-adapter.hpp.

pointer

template<class POS , class CON >

using pointer = _ValTrait::pointer

Definition at line 217 of file iter-adapter.hpp.

ConRef

template<class POS , class CON >

using ConRef = meta::RefTraits<CON>::Reference

protected

Definition at line 305 of file iter-adapter.hpp.

Member Function Documentation

operator bool()

template<class POS , class CON >

operator bool ( ) const

inlineexplicit

Definition at line 233 of file iter-adapter.hpp.

References IterAdapter< POS, CON >::isValid().

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operator*()

template<class POS , class CON >

reference operator* ( ) const

inline

Definition at line 242 of file iter-adapter.hpp.

References IterAdapter< POS, CON >::_maybe_throw(), and IterAdapter< POS, CON >::pos_.

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operator->()

template<class POS , class CON >

pointer operator-> ( ) const

inline

Definition at line 249 of file iter-adapter.hpp.

References IterAdapter< POS, CON >::_maybe_throw(), and IterAdapter< POS, CON >::pos_.

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operator++()

template<class POS , class CON >

IterAdapter & operator++ ( )

inline

Definition at line 256 of file iter-adapter.hpp.

References IterAdapter< POS, CON >::_maybe_throw(), and IterAdapter< POS, CON >::iterate().

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isValid()

template<class POS , class CON >

bool isValid ( ) const

inline

Definition at line 264 of file iter-adapter.hpp.

References IterAdapter< POS, CON >::check().

Referenced by IterAdapter< POS, CON >::_maybe_throw(), IterAdapter< POS, CON >::empty(), and IterAdapter< POS, CON >::operator bool().

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empty()

template<class POS , class CON >

bool empty ( ) const

inline

Definition at line 270 of file iter-adapter.hpp.

References IterAdapter< POS, CON >::isValid().

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check()

template<class POS , class CON >

bool check ( ) const

inlineprotected

ask the controlling container if this position is valid.

Note

this function is called before any operation, thus the container may adjust the position value, for example setting it to a "stop iteration" mark.

Definition at line 284 of file iter-adapter.hpp.

References IterAdapter< POS, CON >::pos_, and IterAdapter< POS, CON >::source_.

Referenced by IterAdapter< POS, CON >::IterAdapter(), IterAdapter< POS, CON >::isValid(), IterAdapter< POS, CON >::iterate(), and IterAdapter< POS, CON >::resetPos().

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iterate()

template<class POS , class CON >

void iterate ( )

inlineprotected

ask the controlling container to yield the next position.

The call is dispatched only if the current position is valid; any new position reached will typically be validated prior to any further access, through invocation of check.

Definition at line 295 of file iter-adapter.hpp.

References IterAdapter< POS, CON >::check(), IterAdapter< POS, CON >::pos_, and IterAdapter< POS, CON >::source_.

Referenced by IterAdapter< POS, CON >::operator++().

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source() [1/2]

template<class POS , class CON >

ConRef source ( )

inlineprotected

allow derived classes to access backing container

Definition at line 308 of file iter-adapter.hpp.

References IterAdapter< POS, CON >::source_.

source() [2/2]

template<class POS , class CON >

const ConRef source ( ) const

inlineprotected

Definition at line 309 of file iter-adapter.hpp.

resetPos()

template<class POS , class CON >

void resetPos ( POS  otherPos )

inlineprotected

Definition at line 312 of file iter-adapter.hpp.

References IterAdapter< POS, CON >::check(), and IterAdapter< POS, CON >::pos_.

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_maybe_throw()

template<class POS , class CON >

void _maybe_throw ( ) const

inlineprivate

Definition at line 320 of file iter-adapter.hpp.

References IterAdapter< POS, CON >::isValid().

Referenced by IterAdapter< POS, CON >::operator*(), IterAdapter< POS, CON >::operator++(), and IterAdapter< POS, CON >::operator->().

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ENABLE_USE_IN_STD_RANGE_FOR_LOOPS()

template<class POS , class CON >

ENABLE_USE_IN_STD_RANGE_FOR_LOOPS

(

IterAdapter< POS, CON >

)

Member Data Documentation

source_

template<class POS , class CON >

CON source_

private

Definition at line 209 of file iter-adapter.hpp.

Referenced by IterAdapter< POS, CON >::check(), IterAdapter< POS, CON >::iterate(), and IterAdapter< POS, CON >::source().

pos_

template<class POS , class CON >

POS pos_

mutableprivate

Definition at line 210 of file iter-adapter.hpp.

Referenced by IterAdapter< POS, CON >::check(), IterAdapter< POS, CON >::iterate(), IterAdapter< POS, CON >::operator*(), IterAdapter< POS, CON >::operator->(), lib::operator==(), and IterAdapter< POS, CON >::resetPos().

Friends And Related Symbol Documentation

operator==

template<class POS , class CON >

template<class P1 , class P2 , class CX >

bool operator== ( IterAdapter< P1, CX > const &  , IterAdapter< P2, CX > const &    )

friend

comparison is allowed to access impl iterator

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

• iter-adapter.hpp