src/corelib/tools/qvsnprintf.cpp
author Alex Gilkes <alex.gilkes@nokia.com>
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/****************************************************************************
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**
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** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies).
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** All rights reserved.
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** Contact: Nokia Corporation (qt-info@nokia.com)
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**
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** This file is part of the QtCore module of the Qt Toolkit.
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**
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** $QT_BEGIN_LICENSE:LGPL$
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** No Commercial Usage
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** This file contains pre-release code and may not be distributed.
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** You may use this file in accordance with the terms and conditions
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** contained in the Technology Preview License Agreement accompanying
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** this package.
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**
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** GNU Lesser General Public License Usage
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** Alternatively, this file may be used under the terms of the GNU Lesser
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** General Public License version 2.1 as published by the Free Software
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** Foundation and appearing in the file LICENSE.LGPL included in the
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** packaging of this file.  Please review the following information to
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** ensure the GNU Lesser General Public License version 2.1 requirements
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** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
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**
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** In addition, as a special exception, Nokia gives you certain additional
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** rights.  These rights are described in the Nokia Qt LGPL Exception
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** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
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**
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** If you have questions regarding the use of this file, please contact
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** Nokia at qt-info@nokia.com.
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**
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**
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**
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**
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**
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**
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**
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**
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** $QT_END_LICENSE$
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**
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****************************************************************************/
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#include "qplatformdefs.h"
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#include "qbytearray.h"
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#include "qstring.h"
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#include "string.h"
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QT_BEGIN_NAMESPACE
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#ifndef QT_VSNPRINTF
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/*!
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    \relates QByteArray
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    A portable \c vsnprintf() function. Will call \c ::vsnprintf(), \c
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    ::_vsnprintf(), or \c ::vsnprintf_s depending on the system, or
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    fall back to an internal version.
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    \a fmt is the \c printf() format string. The result is put into
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    \a str, which is a buffer of at least \a n bytes.
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    The caller is responsible to call \c va_end() on \a ap.
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    \warning Since vsnprintf() shows different behavior on certain
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    platforms, you should not rely on the return value or on the fact
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    that you will always get a 0 terminated string back.
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    Ideally, you should never call this function but use QString::sprintf()
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    instead.
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    \sa qsnprintf(), QString::sprintf()
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*/
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int qvsnprintf(char *str, size_t n, const char *fmt, va_list ap)
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{
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    if (!str || !fmt)
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        return -1;
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    QString buf;
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    buf.vsprintf(fmt, ap);
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    QByteArray ba = buf.toLocal8Bit();
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    if (n > 0) {
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        size_t blen = qMin(size_t(ba.length()), size_t(n - 1));
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        memcpy(str, ba.constData(), blen);
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        str[blen] = '\0'; // make sure str is always 0 terminated
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    }
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    return ba.length();
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}
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#else
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QT_BEGIN_INCLUDE_NAMESPACE
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#include <stdio.h>
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QT_END_INCLUDE_NAMESPACE
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int qvsnprintf(char *str, size_t n, const char *fmt, va_list ap)
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{
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    return QT_VSNPRINTF(str, n, fmt, ap);
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}
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#endif
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/*!
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    \relates QByteArray
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    A portable snprintf() function, calls qvsnprintf.
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    \a fmt is the \c printf() format string. The result is put into
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    \a str, which is a buffer of at least \a n bytes.
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    \warning Call this function only when you know what you are doing
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    since it shows different behavior on certain platforms.
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    Use QString::sprintf() to format a string instead.
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    \sa qvsnprintf(), QString::sprintf()
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*/
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int qsnprintf(char *str, size_t n, const char *fmt, ...)
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{
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    va_list ap;
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    va_start(ap, fmt);
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    int ret = qvsnprintf(str, n, fmt, ap);
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    va_end(ap);
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    return ret;
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}
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QT_END_NAMESPACE