QStringBuilder< A, B > Class Template Reference

\inmodule QtCore More...

#include <qstringbuilder.h>

Inheritance diagram for QStringBuilder< A, B >:

Collaboration diagram for QStringBuilder< A, B >:

Public Types
typedef Concatenable::ConvertTo	ConvertTo

Public Member Functions
	QStringBuilder (A &&a_, B &&b_)
	QStringBuilder (QStringBuilder &&)=default
	QStringBuilder (const QStringBuilder &)=default
	~QStringBuilder ()=default
	operator ConvertTo () const
qsizetype	size () const
bool	isNull () const
Public Member Functions inherited from QStringBuilderCommon< Builder, T >
T	toUpper () const
T	toLower () const

Public Attributes
A	a
B	b

Friends
class	QByteArray
class	QString

Additional Inherited Members
Protected Member Functions inherited from QStringBuilderCommon< Builder, T >
T	resolved () const

Detailed Description

template<typename A, typename B>
class QStringBuilder< A, B >

\inmodule QtCore

\reentrant

Since

4.6

The QStringBuilder class is a template class that provides a facility to build up QStrings and QByteArrays from smaller chunks.

To build a QString by multiple concatenations, QString::operator+() is typically used. This causes {n - 1} allocations when building a string from {n} chunks. The same is true for QByteArray.

QStringBuilder uses expression templates to collect the individual chunks, compute the total size, allocate the required amount of memory for the final string object, and copy the chunks into the allocated memory.

The QStringBuilder class is not to be used explicitly in user code. Instances of the class are created as return values of the operator%() function, acting on objects of the following types:

For building QStrings:

\list

• QString, (since 5.10:) QStringView
• QChar, QLatin1Char, (since 5.10:) char16_t,
• QLatin1StringView,
• (since 5.10:) {const char16_t[]} ({u"foo"}),
• QByteArray, char, {const char[]}. \endlist

The types in the last list point are only available when QT_NO_CAST_FROM_ASCII is not defined.

For building QByteArrays:

\list

• QByteArray, char, {const char[]}. \endlist

Concatenating strings with operator%() generally yields better performance than using QString::operator+() on the same chunks if there are three or more of them, and performs equally well in other cases.

Note

Defining QT_USE_QSTRINGBUILDER at build time (this is the default when building Qt libraries and tools), will make using {'+'} when concatenating strings work the same way as operator%().

See also

QLatin1StringView, QString

Definition at line 78 of file qstringbuilder.h.

Member Typedef Documentation

ConvertTo

template<typename A , typename B >

typedef Concatenable::ConvertTo QStringBuilder< A, B >::ConvertTo

Definition at line 122 of file qstringbuilder.h.

Constructor & Destructor Documentation

QStringBuilder() [1/3]

template<typename A , typename B >

QStringBuilder< A, B >::QStringBuilder ( A &&  a_, B &&  b_  )

inline

Definition at line 86 of file qstringbuilder.h.

QStringBuilder() [2/3]

template<typename A , typename B >

QStringBuilder< A, B >::QStringBuilder ( QStringBuilder< A, B > &&  )

default

QStringBuilder() [3/3]

template<typename A , typename B >

QStringBuilder< A, B >::QStringBuilder ( const QStringBuilder< A, B > &  )

default

~QStringBuilder()

template<typename A , typename B >

QStringBuilder< A, B >::~QStringBuilder ( )

default

Member Function Documentation

isNull()

template<typename A , typename B >

bool QStringBuilder< A, B >::isNull ( ) const

inline

Definition at line 127 of file qstringbuilder.h.

References QtStringBuilder::isNull().

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operator ConvertTo()

template<typename A , typename B >

QStringBuilder< A, B >::operator ConvertTo ( ) const

inline

Definition at line 123 of file qstringbuilder.h.

size()

template<typename A , typename B >

qsizetype QStringBuilder< A, B >::size ( ) const

inline

Definition at line 125 of file qstringbuilder.h.

References QConcatenable< QStringBuilder< A, B > >::size().

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Friends And Related Symbol Documentation

QByteArray

template<typename A , typename B >

friend class QByteArray

friend

Definition at line 93 of file qstringbuilder.h.

QString

template<typename A , typename B >

friend class QString

friend

Definition at line 94 of file qstringbuilder.h.

Member Data Documentation

a

template<typename A , typename B >

A QStringBuilder< A, B >::a

Definition at line 132 of file qstringbuilder.h.

b

template<typename A , typename B >

B QStringBuilder< A, B >::b

Definition at line 133 of file qstringbuilder.h.

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

• qtbase/src/corelib/text/qstringbuilder.h