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/****************************************************************************
**
** Copyright (C) 2021 The Qt Company Ltd.
** Contact: https://www.qt.io/licensing/
**
** This file is part of the QtCore module of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:COMM$
**
** Commercial License Usage
** Licensees holding valid commercial Qt licenses may use this file in
** accordance with the commercial license agreement provided with the
** Software or, alternatively, in accordance with the terms contained in
** a written agreement between you and The Qt Company. For licensing terms
** and conditions see https://www.qt.io/terms-conditions. For further
** information use the contact form at https://www.qt.io/contact-us.
**
** $QT_END_LICENSE$
**
**
**
**
**
**
**
**
**
**
**
**
**
**
**
**
**
**
**
****************************************************************************/
#include "qstringbuilder.h"
#include <private/qutfcodec_p.h>
QT_BEGIN_NAMESPACE
/*!
\class QStringBuilder
\inmodule QtCore
\internal
\reentrant
\since 4.6
\brief The QStringBuilder class is a template class that provides a facility to build up QStrings and QByteArrays from smaller chunks.
\ingroup tools
\ingroup shared
\ingroup string-processing
To build a QString by multiple concatenations, QString::operator+()
is typically used. This causes \e{n - 1} allocations when building
a string from \e{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
\li QString, QStringRef, (since 5.10:) QStringView
\li QChar, QCharRef, QLatin1Char, (since 5.10:) \c char16_t,
\li QLatin1String,
\li (since 5.10:) \c{const char16_t[]} (\c{u"foo"}),
\li QByteArray, \c char, \c{const char[]}.
\endlist
The types in the last list point are only available when
\c QT_NO_CAST_FROM_ASCII is not defined.
For building QByteArrays:
\list
\li QByteArray, \c char, \c{const char[]}.
\endlist
Concatenating strings with operator%() generally yields better
performance than using \c QString::operator+() on the same chunks
if there are three or more of them, and performs equally well in other
cases.
\sa QLatin1String, QString
*/
/*! \fn template <typename A, typename B> QStringBuilder<A, B>::QStringBuilder(const A &a, const B &b)
Constructs a QStringBuilder from \a a and \a b.
*/
/* \fn template <typename A, typename B> QStringBuilder<A, B>::operator%(const A &a, const B &b)
Returns a \c QStringBuilder object that is converted to a QString object
when assigned to a variable of QString type or passed to a function that
takes a QString parameter.
This function is usable with arguments of type \c QString,
\c QLatin1String, \c QStringRef,
\c QChar, \c QCharRef, \c QLatin1Char, and \c char.
*/
/* \fn template <typename A, typename B> QByteArray QStringBuilder<A, B>::toLatin1() const
Returns a Latin-1 representation of the string as a QByteArray. The
returned byte array is undefined if the string contains non-Latin1
characters.
*/
/* \fn template <typename A, typename B> QByteArray QStringBuilder<A, B>::toUtf8() const
Returns a UTF-8 representation of the string as a QByteArray.
*/
/*!
\internal
*/
void QAbstractConcatenable::convertFromAscii(const char *a, int len, QChar *&out) noexcept
{
if (Q_UNLIKELY(len == -1)) {
if (!a)
return;
len = int(strlen(a));
}
out = QUtf8::convertToUnicode(out, a, len);
}
QT_END_NAMESPACE
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