QFuture< T >::const_iterator Class Reference

The QFuture::const_iterator class provides an STL-style const iterator for QFuture. More...

#include <qfuture.h>

Public Types
typedef qptrdiff	difference_type
	Typedef for ptrdiff_t. More...
typedef std::bidirectional_iterator_tag	iterator_category
	Typedef for std::bidirectional_iterator_tag. More...
typedef const T *	pointer
	Typedef for const T *. More...
typedef const T &	reference
	Typedef for const T &. More...
typedef T	value_type
	Typedef for T. More...

Public Functions
	const_iterator ()
	Constructs an uninitialized iterator. More...
	const_iterator (QFuture const *const _future, int _index)
	const_iterator (const const_iterator &o)
	Constructs a copy of other. More...
bool	operator!= (const const_iterator &other) const
	Returns true if other points to a different result than this iterator; otherwise returns false. More...
const T &	operator* () const
	Returns the current result. More...
const_iterator	operator+ (int j) const
	Returns an iterator to the results at j positions forward from this iterator. More...
const_iterator &	operator++ ()
	The prefix ++ operator (++it) advances the iterator to the next result in the future and returns an iterator to the new current result. More...
const_iterator	operator++ (int)
	The postfix ++ operator (it++) advances the iterator to the next result in the future and returns an iterator to the previously current result. More...
const_iterator &	operator+= (int j)
	Advances the iterator by j results. More...
const_iterator	operator- (int j) const
	Returns an iterator to the result at j positions backward from this iterator. More...
const_iterator &	operator-- ()
	The prefix – operator (–it) makes the preceding result current and returns an iterator to the new current result. More...
const_iterator	operator-- (int)
	The postfix – operator (it–) makes the preceding result current and returns an iterator to the previously current result. More...
const_iterator &	operator-= (int j)
	Makes the iterator go back by j results. More...
const T *	operator-> () const
	Returns a pointer to the current result. More...
const_iterator &	operator= (const const_iterator &o)
	Assigns other to this iterator. More...
bool	operator== (const const_iterator &o) const
	Returns true if other points to the same result as this iterator; otherwise returns false. More...

Properties
QFuture const *	future
int	index

Detailed Description

template<typename T>
class QFuture< T >::const_iterator

The QFuture::const_iterator class provides an STL-style const iterator for QFuture.

Note

This class or function is reentrant.

Since

4.4

QFuture provides both STL-style iterators and Java-style iterators. The STL-style iterators are more low-level and more cumbersome to use; on the other hand, they are slightly faster and, for developers who already know STL, have the advantage of familiarity.

The default QFuture::const_iterator constructor creates an uninitialized iterator. You must initialize it using a QFuture function like QFuture::constBegin() or QFuture::constEnd() before you start iterating. Here's a typical loop that prints all the results available in a future:

QFuture<QString> future = ...;

QFuture<QString>::const_iterator i;
for (i = future.constBegin(); i != future.constEnd(); ++i)
    cout << *i << endl;

See also

QFutureIterator, QFuture

Definition at line 110 of file qfuture.h.

Typedefs

difference_type

template<typename T>

QFuture< T >::const_iterator::difference_type

Typedef for ptrdiff_t.

Provided for STL compatibility.

Definition at line 114 of file qfuture.h.

iterator_category

template<typename T>

QFuture< T >::const_iterator::iterator_category

Typedef for std::bidirectional_iterator_tag.

Provided for STL compatibility.

Definition at line 113 of file qfuture.h.

pointer

template<typename T>

QFuture< T >::const_iterator::pointer

Typedef for const T *.

Provided for STL compatibility.

Definition at line 116 of file qfuture.h.

reference

template<typename T>

QFuture< T >::const_iterator::reference

Typedef for const T &.

Provided for STL compatibility.

Definition at line 117 of file qfuture.h.

value_type

template<typename T>

QFuture< T >::const_iterator::value_type

Typedef for T.

Provided for STL compatibility.

Definition at line 115 of file qfuture.h.

Constructors and Destructors

const_iterator() [1/3]

template<typename T>

QFuture< T >::const_iterator::const_iterator ( )

inline

Constructs an uninitialized iterator.

Functions like operator*() and operator++() should not be called on an uninitialized iterartor. Use operator=() to assign a value to it before using it.

See also

QFuture::constBegin() QFuture::constEnd()

Definition at line 119 of file qfuture.h.

Referenced by QFuture< T >::begin(), QFuture< T >::constBegin(), QFuture< T >::constEnd(), QFuture< T >::end(), QFuture< T >::const_iterator::operator+(), and QFuture< T >::const_iterator::operator-().

{}

const_iterator() [2/3]

template<typename T>

QFuture< T >::const_iterator::const_iterator ( QFuture const *const  future, int  index  )

inline

Warning

This function is not part of the public interface.

Definition at line 120 of file qfuture.h.

: future(_future), index(_index) {}

const_iterator() [3/3]

template<typename T>

QFuture< T >::const_iterator::const_iterator ( const const_iterator &  o )

inline

Constructs a copy of other.

Definition at line 121 of file qfuture.h.

: future(o.future), index(o.index)  {}

Functions

operator!=()

template<typename T>

bool QFuture< T >::const_iterator::operator!= ( const const_iterator &  other ) const

inline

Returns true if other points to a different result than this iterator; otherwise returns false.

See also

operator==()

Definition at line 127 of file qfuture.h.

Referenced by QFutureInterface< T >::future(), and QFuture< T >::const_iterator::operator==().

        {
            if (index == -1 && other.index == -1) // comparing end != end?
                return false;
            if (other.index == -1)
                return (future->isRunning() || (index < future->resultCount()));
            return (index != other.index);
        }

operator*()

template<typename T>

const T & QFuture< T >::const_iterator::operator* ( ) const

inline

Returns the current result.

Definition at line 124 of file qfuture.h.

{ return future->d.resultReference(index); }

operator+()

template<typename T>

QFuture::const_iterator QFuture< T >::const_iterator::operator+ ( int  j ) const

inline

Returns an iterator to the results at j positions forward from this iterator.

(If j is negative, the iterator goes backward.)

See also

operator-(), operator+=()

Definition at line 141 of file qfuture.h.

{ return const_iterator(future, index + j); }

operator++() [1/2]

template<typename T>

QFuture::const_iterator & QFuture< T >::const_iterator::operator++ ( )

inline

The prefix ++ operator (++it) advances the iterator to the next result in the future and returns an iterator to the new current result.

Calling this function on QFuture::constEnd() leads to undefined results.

See also

operator--()

Definition at line 137 of file qfuture.h.

{ ++index; return *this; }

operator++() [2/2]

template<typename T>

QFuture::const_iterator QFuture< T >::const_iterator::operator++ ( int  )

inline

The postfix ++ operator (it++) advances the iterator to the next result in the future and returns an iterator to the previously current result.

This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.

Definition at line 138 of file qfuture.h.

{ const_iterator r = *this; ++index; return r; }

operator+=()

template<typename T>

QFuture::const_iterator & QFuture< T >::const_iterator::operator+= ( int  j )

inline

Advances the iterator by j results.

(If j is negative, the iterator goes backward.)

See also

operator-=(), operator+()

Definition at line 143 of file qfuture.h.

{ index += j; return *this; }

operator-()

template<typename T>

QFuture::const_iterator QFuture< T >::const_iterator::operator- ( int  j ) const

inline

Returns an iterator to the result at j positions backward from this iterator.

(If j is negative, the iterator goes forward.)

See also

operator+(), operator-=()

Definition at line 142 of file qfuture.h.

{ return const_iterator(future, index - j); }

operator--() [1/2]

template<typename T>

QFuture::const_iterator & QFuture< T >::const_iterator::operator-- ( )

inline

The prefix – operator (–it) makes the preceding result current and returns an iterator to the new current result.

Calling this function on QFuture::constBegin() leads to undefined results.

See also

operator++()

Definition at line 139 of file qfuture.h.

{ --index; return *this; }

operator--() [2/2]

template<typename T>

QFuture::const_iterator QFuture< T >::const_iterator::operator-- ( int  )

inline

The postfix – operator (it–) makes the preceding result current and returns an iterator to the previously current result.

This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.

Definition at line 140 of file qfuture.h.

{ const_iterator r = *this; --index; return r; }

operator-=()

template<typename T>

QFuture::const_iterator & QFuture< T >::const_iterator::operator-= ( int  j )

inline

Makes the iterator go back by j results.

(If j is negative, the iterator goes forward.)

See also

operator+=(), operator-()

Definition at line 144 of file qfuture.h.

{ index -= j; return *this; }

operator->()

template<typename T>

const T * QFuture< T >::const_iterator::operator-> ( ) const

inline

Returns a pointer to the current result.

Definition at line 125 of file qfuture.h.

{ return future->d.resultPointer(index); }

operator=()

template<typename T>

QFuture::const_iterator & QFuture< T >::const_iterator::operator= ( const const_iterator &  o )

inline

Assigns other to this iterator.

Definition at line 122 of file qfuture.h.

Referenced by QFutureInterface< T >::future().

        { future = o.future; index = o.index; return *this; }

operator==()

template<typename T>

bool QFuture< T >::const_iterator::operator== ( const const_iterator &  other ) const

inline

Returns true if other points to the same result as this iterator; otherwise returns false.

See also

operator!=()

Definition at line 136 of file qfuture.h.

Referenced by QFutureInterface< T >::future().

{ return !operator!=(o); }

Properties

future

template<typename T>

QFuture const* QFuture< T >::const_iterator::future

private

Definition at line 146 of file qfuture.h.

Referenced by QFuture< T >::const_iterator::operator!=(), QFuture< T >::const_iterator::operator*(), QFuture< T >::const_iterator::operator+(), QFuture< T >::const_iterator::operator-(), QFuture< T >::const_iterator::operator->(), and QFuture< T >::const_iterator::operator=().

index

template<typename T>

int QFuture< T >::const_iterator::index

private

Definition at line 147 of file qfuture.h.

Referenced by QFuture< T >::const_iterator::operator!=(), QFuture< T >::const_iterator::operator++(), QFuture< T >::const_iterator::operator--(), and QFuture< T >::const_iterator::operator=().

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

• /src/corelib/concurrent/qfuture.h
• /src/corelib/concurrent/qfuture.cpp