QSyntaxHighlighter

#include <QtGui>

#include "highlighter.h"

Highlighter::Highlighter(QTextDocument *parent, FileMode mode)
    : QSyntaxHighlighter(parent)
{
    this->filemode = mode;
    HighlightingRule rule;

    keywordFormat.setForeground(QColor(0x80, 0x80, 0x00));
    QStringList keywordPatterns;
    keywordPatterns << "\\bclass\\b" << "\\bconst\\b" << "\\bexplicit\\b"
                    << "\\bfriend\\b" << "\\binline\\b" << "\\bnamespace\\b"
                    << "\\bprivate\\b" << "\\bprotected\\b" << "\\bpublic\\b"
                    << "\\bsignals\\b" << "\\bslots\\b" << "\\bstatic\\b"
                    << "\\btypename\\b" << "\\bvolatile\\b" << "\\bnew\\b"
                    << "\\bdelete\\b" << "\\btrue\\b" << "\\bfalse\\b"
                    << "\\bdouble\\b" << "\\bchar\\b" << "\\bthis\\b"
                    << "\\blong\\b" << "\\bshort\\b" << "\\bsigned\\b"
                    << "\\bstruct\\b" << "\\bvoid\\b" << "\\bunion\\b"
                    << "\\bvirtual\\b" << "\\btypedef\\b" << "\\bunsigned\\b"
                    << "\\benum\\b" << "\\bint\\b" << "\\boperator\\b"
                    << "\\btemplate\\b" << "\\bfunction\\b" << "\\busing\\b"
                    << "\\bif\\b" << "\\belse\\b" << "\\belseif\\b"
                    << "\\bswitch\\b" << "\\bcase\\b" << "\\bbreak\\b"
                    << "\\bcontinue\\b" << "\\bfor\\b" << "\\bwhile\\b"
                    << "\\bforever\\b" << "\\btry\\b" << "\\bcatch\\b"
                    << "\\bfinally\\b" << "\\breturn\\n" << "\\btypeof\\b"
                    << "\\binstanceof\\b" << "\\binclude\\b" << "\\brequire\\b";
    foreach(const QString &pattern, keywordPatterns){
        rule.pattern = QRegExp(pattern);
        rule.format = keywordFormat;
        highlightingRules.append(rule);
    }

    numberFormat.setForeground(QColor(0x00, 0x00, 0x80));
    rule.pattern = QRegExp("\\b(?:0x)?[0-9]+\\b");
    rule.format = numberFormat;
    highlightingRules.append(rule);

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

    quotationFormat.setForeground(Qt::darkGreen);

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

    precompileFormat.setForeground(Qt::darkBlue);
    rule.pattern = QRegExp("\\b#[a-z]+\\b");
    rule.format = precompileFormat;
    highlightingRules.append(rule);

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

    multiLineCommentFormat.setForeground(Qt::darkGreen);

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

void Highlighter::highlightBlock(const QString &text)
{
    foreach(const HighlightingRule &rule, highlightingRules){
        QRegExp expression(rule.pattern);
        int index = expression.indexIn(text);
        int length = expression.matchedLength();

        while (index >= 0) {
            setFormat(index, length, rule.format);
            index = expression.indexIn(text, index + length);
        }
    }

    int quotationStart = 0, quotationEnd = 0;
    QChar edge = '"';
    bool inQuotation = false;
    for(int i = 0; i < text.length(); i++){
        if(inQuotation && text.at(i) == '\\'){
            i++;
            continue;
        }

        if(!inQuotation){
            if(text.at(i) == '"' || text.at(i) == '\'' || text.at(i) == '`'){
                quotationStart = i;
                inQuotation = true;
                edge = text.at(i);
            }

        }else{
            if(text.at(i) == edge){
                quotationEnd = i;
                inQuotation = false;
                setFormat(quotationStart, quotationEnd - quotationStart + 1, quotationFormat);
            }
        }
    }

    setCurrentBlockState(0);
    int startIndex = 0;
    if(previousBlockState() != 1){
        startIndex = commentStartExpression.indexIn(text);
    }

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


Highlighter::FileMode Highlighter::fileMode() const{
    return filemode;
}

void Highlighter::setFileMode(FileMode mode){
    this->filemode = mode;
}