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# highlighter.cpp Example File
richtext/syntaxhighlighter/highlighter.cpp

        /****************************************************************************
        **
        ** Copyright (C) 2005-2006 Trolltech ASA. All rights reserved.
        **
        ** This file is part of the example classes of the Qt Toolkit.
        **
        ** Licensees holding valid Qt Preview licenses may use this file in
        ** accordance with the Qt Preview License Agreement provided with the
        ** Software.
        **
        ** See http://www.trolltech.com/pricing.html or email sales@trolltech.com for
        ** information about Qt Commercial License Agreements.
        **
        ** Contact info@trolltech.com if any conditions of this licensing are
        ** not clear to you.
        **
        ** This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
        ** WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
        **
        ****************************************************************************/

        #include <QtGui>

        #include "highlighter.h"

        Highlighter::Highlighter(QTextDocument *parent)
            : QSyntaxHighlighter(parent)
        {
            HighlightingRule rule;

            keywordFormat.setForeground(Qt::darkBlue);
            keywordFormat.setFontWeight(QFont::Bold);
            QStringList keywordPatterns;
            keywordPatterns << "\\bchar\\b" << "\\bclass\\b" << "\\bconst\\b"
                            << "\\bdouble\\b" << "\\benum\\b" << "\\bexplicit\\b"
                            << "\\bfriend\\b" << "\\binline\\b" << "\\bint\\b"
                            << "\\blong\\b" << "\\bnamespace\\b" << "\\boperator\\b"
                            << "\\bprivate\\b" << "\\bprotected\\b" << "\\bpublic\\b"
                            << "\\bshort\\b" << "\\bsignals\\b" << "\\bsigned\\b"
                            << "\\bslots\\b" << "\\bstatic\\b" << "\\bstruct\\b"
                            << "\\btemplate\\b" << "\\btypedef\\b" << "\\btypename\\b"
                            << "\\bunion\\b" << "\\bunsigned\\b" << "\\bvirtual\\b"
                            << "\\bvoid\\b" << "\\bvolatile\\b";
            foreach (QString pattern, keywordPatterns) {
                rule.pattern = QRegExp(pattern);
                rule.format = keywordFormat;
                highlightingRules.append(rule);
            }

            classFormat.setFontWeight(QFont::Bold);
            classFormat.setForeground(Qt::darkMagenta);
            rule.pattern = QRegExp("\\bQ[A-Za-z]+\\b");
            rule.format = classFormat;
            highlightingRules.append(rule);

            singleLineCommentFormat.setForeground(Qt::red);
            rule.pattern = QRegExp("//[^\n]*");
            rule.format = singleLineCommentFormat;
            highlightingRules.append(rule);

            multiLineCommentFormat.setForeground(Qt::red);

            quotationFormat.setForeground(Qt::darkGreen);
            rule.pattern = QRegExp("\".*\"");
            rule.format = quotationFormat;
            highlightingRules.append(rule);

            functionFormat.setFontItalic(true);
            functionFormat.setForeground(Qt::blue);
            rule.pattern = QRegExp("\\b[A-Za-z0-9_]+(?=\\()");
            rule.format = functionFormat;
            highlightingRules.append(rule);

            commentStartExpression = QRegExp("/\\*");
            commentEndExpression = QRegExp("\\*/");
        }

        void Highlighter::highlightBlock(const QString &text)
        {
            foreach (HighlightingRule rule, highlightingRules) {
                QRegExp expression(rule.pattern);
                int index = text.indexOf(expression);
                while (index >= 0) {
                    int length = expression.matchedLength();
                    setFormat(index, length, rule.format);
                    index = text.indexOf(expression, index + length);
                }
            }
            setCurrentBlockState(0);

            int startIndex = 0;
            if (previousBlockState() != 1)
                startIndex = text.indexOf(commentStartExpression);

            while (startIndex >= 0) {
               int endIndex = text.indexOf(commentEndExpression, startIndex);
               int commentLength;
               if (endIndex == -1) {
                   setCurrentBlockState(1);
                   commentLength = text.length() - startIndex;
               } else {
                   commentLength = endIndex - startIndex
                                   + commentEndExpression.matchedLength();
               }
               setFormat(startIndex, commentLength, multiLineCommentFormat);
               startIndex = text.indexOf(commentStartExpression,
                                                       startIndex + commentLength);
            }
        }