QStringBuilder< A, B > Class Template Reference

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

#include <qstringbuilder.h>

Public Functions
	operator ConvertTo () const
	QStringBuilder (const A &a_, const B &b_)
	Constructs a QStringBuilder from a and b. More...
int	size () const
QByteArray	toLatin1 () const
	Returns a Latin-1 representation of the string as a QByteArray. More...

Public Variables
const A &	a
const B &	b

Private Types
typedef QConcatenable< QStringBuilder< A, B > >	Concatenable
typedef Concatenable::ConvertTo	ConvertTo

Private Functions
template<typename T >
T	convertTo () const

Friends
class	QByteArray
class	QString

Detailed Description

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

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

Warning

This function is not part of the public interface.

Note

This class or function is reentrant.

Since

4.6

To build a QString by multiple concatenations, QString::operator+() is typically used. This causes n - 1 reallocations when building a string from n chunks.

QStringBuilder uses expression templates to collect the individual chunks, compute the total size, allocate the required amount of memory for the final QString 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 type QString, QLatin1String, QLatin1Literal, QStringRef, QChar, QCharRef, QLatin1Char, and char.

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

See also

QLatin1Literal, QString

Definition at line 112 of file qstringbuilder.h.

Typedefs

Concatenable

template<typename A, typename B>

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

private

Definition at line 136 of file qstringbuilder.h.

ConvertTo

template<typename A, typename B>

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

private

Definition at line 137 of file qstringbuilder.h.

Constructors and Destructors

QStringBuilder()

template<typename A, typename B>

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

inline

Constructs a QStringBuilder from a and b.

Definition at line 115 of file qstringbuilder.h.

: a(a_), b(b_) {}

Functions

convertTo()

template<typename A, typename B>

template<typename T >

T QStringBuilder< A, B >::convertTo ( ) const

inlineprivate

Definition at line 119 of file qstringbuilder.h.

    {
        const uint len = QConcatenable< QStringBuilder<A, B> >::size(*this);
        T s(len, Qt::Uninitialized);

        typename T::iterator d = s.data();
        typename T::const_iterator const start = d;
        QConcatenable< QStringBuilder<A, B> >::appendTo(*this, d);

        if (!QConcatenable< QStringBuilder<A, B> >::ExactSize && int(len) != d - start) {
            // this resize is necessary since we allocate a bit too much
            // when dealing with variable sized 8-bit encodings
            s.resize(d - start);
        }
        return s;
    }

operator ConvertTo()

template<typename A, typename B>

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

inline

Definition at line 139 of file qstringbuilder.h.

{ return convertTo<ConvertTo>(); }

size()

template<typename A, typename B>

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

inline

Definition at line 142 of file qstringbuilder.h.

{ return Concatenable::size(*this); }

toLatin1()

template<typename A, typename B>

QByteArray QStringBuilder< A, B >::toLatin1 ( ) const

inline

Returns a Latin-1 representation of the string as a QByteArray.

The returned byte array is undefined if the string contains non-Latin1 characters.

Definition at line 141 of file qstringbuilder.h.

Referenced by QStringBuilder< A, B >::toLatin1().

{ return convertTo<QString>().toLatin1(); }

Friends and Related Functions

QByteArray

template<typename A, typename B>

friend class QByteArray

friend

Definition at line 117 of file qstringbuilder.h.

QString

template<typename A, typename B>

friend class QString

friend

Definition at line 118 of file qstringbuilder.h.

Properties

a

template<typename A, typename B>

const A& QStringBuilder< A, B >::a

Definition at line 144 of file qstringbuilder.h.

Referenced by QConcatenable< QStringBuilder< A, B > >::appendTo(), and QConcatenable< QStringBuilder< A, B > >::size().

b

template<typename A, typename B>

const B& QStringBuilder< A, B >::b

Definition at line 145 of file qstringbuilder.h.

Referenced by QConcatenable< QStringBuilder< A, B > >::appendTo(), and QConcatenable< QStringBuilder< A, B > >::size().

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

• /src/corelib/tools/qstringbuilder.h
• /src/corelib/tools/qstringbuilder.cpp