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Diffstat (limited to 'src/corelib/tools/qstringbuilder.cpp')
| -rw-r--r-- | src/corelib/tools/qstringbuilder.cpp | 193 |
1 files changed, 193 insertions, 0 deletions
diff --git a/src/corelib/tools/qstringbuilder.cpp b/src/corelib/tools/qstringbuilder.cpp new file mode 100644 index 0000000000..a5dff88f43 --- /dev/null +++ b/src/corelib/tools/qstringbuilder.cpp @@ -0,0 +1,193 @@ +/**************************************************************************** +** +** Copyright (C) 2011 Nokia Corporation and/or its subsidiary(-ies). +** All rights reserved. +** Contact: Nokia Corporation (qt-info@nokia.com) +** +** This file is part of the QtCore module of the Qt Toolkit. +** +** $QT_BEGIN_LICENSE:LGPL$ +** No Commercial Usage +** This file contains pre-release code and may not be distributed. +** You may use this file in accordance with the terms and conditions +** contained in the Technology Preview License Agreement accompanying +** this package. +** +** GNU Lesser General Public License Usage +** Alternatively, this file may be used under the terms of the GNU Lesser +** General Public License version 2.1 as published by the Free Software +** Foundation and appearing in the file LICENSE.LGPL included in the +** packaging of this file. Please review the following information to +** ensure the GNU Lesser General Public License version 2.1 requirements +** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html. +** +** In addition, as a special exception, Nokia gives you certain additional +** rights. These rights are described in the Nokia Qt LGPL Exception +** version 1.1, included in the file LGPL_EXCEPTION.txt in this package. +** +** If you have questions regarding the use of this file, please contact +** Nokia at qt-info@nokia.com. +** +** +** +** +** +** +** +** +** $QT_END_LICENSE$ +** +****************************************************************************/ + +#include "qstringbuilder.h" +#include <QtCore/qtextcodec.h> + +QT_BEGIN_NAMESPACE + +/*! + \class QLatin1Literal + \internal + \reentrant + \since 4.6 + + \brief The QLatin1Literal class provides a thin wrapper around string + literals used in source code. + + \ingroup tools + \ingroup shared + \ingroup string-processing + + + Unlike \c QLatin1String, a \c QLatin1Literal can retrieve its size + without iterating over the literal. + + The main use of \c QLatin1Literal is in conjunction with \c QStringBuilder + to reduce the number of reallocations needed to build up a string from + smaller chunks. + + \sa QStringBuilder, QLatin1String, QString, QStringRef +*/ + +/*! \fn int QLatin1Literal::size() const + + Returns the number of characters in the literal \e{excluding} the trailing + NULL char. +*/ + +/*! \fn QLatin1Literal::QLatin1Literal(const char str) + + Constructs a new literal from the string \a str. +*/ + +/*! \fn const char *QLatin1Literal::data() const + + Returns a pointer to the first character of the string literal. + The string literal is terminated by a NUL character. +*/ + +/*! + \class QStringBuilder + \internal + \reentrant + \since 4.6 + + \brief The QStringBuilder class is a template class that provides a facility to build up QStrings 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} reallocations when building + a string from \e{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 \c char. + + Concatenating strings with operator%() generally yields better + performance then using \c QString::operator+() on the same chunks + if there are three or more of them, and performs equally well in other + cases. + + \sa QLatin1Literal, QString +*/ + +/*! \fn QStringBuilder::QStringBuilder(const A &a, const B &b) + Constructs a QStringBuilder from \a a and \a b. + */ + +/* \fn QStringBuilder::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 QLatin1Literal, \c QStringRef, + \c QChar, \c QCharRef, \c QLatin1Char, and \c char. +*/ + +/*! \fn QByteArray QStringBuilder::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 QStringBuilder::operator QString() const + + Converts the \c QLatin1Literal into a \c QString object. +*/ + +/*! \internal + Note: The len contains the ending \0 + */ +void QAbstractConcatenable::convertFromAscii(const char *a, int len, QChar *&out) +{ +#ifndef QT_NO_TEXTCODEC + if (QString::codecForCStrings && len) { + QString tmp = QString::fromAscii(a, len > 0 ? len - 1 : -1); + memcpy(out, reinterpret_cast<const char *>(tmp.constData()), sizeof(QChar) * tmp.size()); + out += tmp.length(); + return; + } +#endif + if (len == -1) { + while (*a) + *out++ = QLatin1Char(*a++); + } else { + for (int i = 0; i < len - 1; ++i) + *out++ = QLatin1Char(a[i]); + } +} + +/*! \internal */ +void QAbstractConcatenable::convertToAscii(const QChar* a, int len, char*& out) +{ +#ifndef QT_NO_TEXTCODEC + if (QString::codecForCStrings) { + QByteArray tmp = QString::codecForCStrings->fromUnicode(a, len); + memcpy(out, tmp.constData(), tmp.size()); + out += tmp.length(); + return; + } +#endif + if (len == -1) { + while (a->unicode()) + convertToLatin1(*a++, out); + } else { + for (int i = 0; i < len; ++i) + convertToLatin1(a[i], out); + } +} + + +QT_END_NAMESPACE |