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#include <QtCore/QRegExp>
#include <QtCore/QMutexLocker>
#include <QtGui/QTextDocument>

#include "qhelp_global.h"

QString QHelpGlobal::uniquifyConnectionName(const QString &name, void *pointer)
{
    static int counter = 0;
    static QMutex mutex;

    QMutexLocker locker(&mutex);
    if (++counter > 1000)
        counter = 0;

    return QString::fromLatin1("%1-%2-%3").
        arg(name).arg(long(pointer)).arg(counter);
}

QString QHelpGlobal::documentTitle(const QString &content)
{
    QString title = QObject::tr("Untitled");
    if (!content.isEmpty()) {
        int start = content.indexOf(QLatin1String("<title>"), 0, Qt::CaseInsensitive) + 7;
        int end = content.indexOf(QLatin1String("</title>"), 0, Qt::CaseInsensitive);
        if ((end - start) > 0) {
            title = content.mid(start, end - start);
            if (Qt::mightBeRichText(title) || title.contains(QLatin1Char('&'))) {
                QTextDocument doc;
                doc.setHtml(title);
                title = doc.toPlainText();
            }
        }
    }
    return title;
}

QString QHelpGlobal::codecFromData(const QByteArray &data)
{
    QString codec = codecFromXmlData(data);
    if (codec.isEmpty())
        codec = codecFromHtmlData(data);
    return codec.isEmpty() ? QLatin1String("utf-8") : codec;
}

QString QHelpGlobal::codecFromHtmlData(const QByteArray &data)
{
    QString content = QString::fromUtf8(data.constData(), data.size());
    int start = content.indexOf(QLatin1String("<meta"), 0, Qt::CaseInsensitive);
    if (start > 0) {
        int end;
        QRegExp r(QLatin1String("charset=([^\"\\s]+)"));
        while (start != -1) {
            end = content.indexOf(QLatin1Char('>'), start) + 1;
            const QString &meta = content.mid(start, end - start).toLower();
            if (r.indexIn(meta) != -1)
                return r.cap(1);
            start = content.indexOf(QLatin1String("<meta"), end,
                                    Qt::CaseInsensitive);
        }
    }
    return QString();
}

QString QHelpGlobal::codecFromXmlData(const QByteArray &data)
{
    QString content = QString::fromUtf8(data.constData(), data.size());
    const QRegExp encodingExp(QLatin1String("^\\s*<\\?xml version="
        "\"\\d\\.\\d\" encoding=\"([^\"]+)\"\\?>.*"));
    return encodingExp.exactMatch(content) ? encodingExp.cap(1) : QString();
}
