SyntaxHighlighter.cpp

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// ======================================================================
//  SyntaxHighlighter.cpp
// ======================================================================
//                   This file is a part of the book 
//             "Qt 5.10 Professional programming with C++"
//                       http://qt-book.com
// ======================================================================
//  Copyright (c) 2017 by Max Schlee
// ======================================================================

#include <QtGui>
#include "SyntaxHighlighter.h"

// ----------------------------------------------------------------------
SyntaxHighlighter::SyntaxHighlighter(QTextDocument* parent/*= 0*/) 
    : QSyntaxHighlighter(parent)
{
    m_lstKeywords 
       << "foreach"   << "bool"    << "int"    << "void"    << "double"
       << "float"     << "char"    << "delete" << "class"   << "const"
       << "virtual"   << "mutable" << "this"   << "struct"  << "union"
       << "throw"     << "for"     << "if"     << "else"    << "false"
       << "namespace" << "switch"  << "case"   << "public"  << "private"
       << "protected" << "new"     << "return" << "using"   << "true"
       << "->"        << ">>"      << "<<"     << ">"       << "<"
       << "("         << ")"       << "{"      << "}"       << "["
       << "]"         << "+"       << "-"      << "*"       << "/"
       << "="         << "!"       << "."      << ","       << ";"
       << ":"         << "&"       << "emit"   << "connect" << "SIGNAL"
       << "|"         << "SLOT"    << "slots"  << "signals";
}

// ----------------------------------------------------------------------
/*virtual*/ void SyntaxHighlighter::highlightBlock(const QString& str)
{
    int nState = previousBlockState();
    int nStart = 0; 
    for (int i = 0; i < str.length(); ++i) {
        if (nState == InsideCStyleComment) {
            if (str.mid(i, 2) == "*/") {
                nState = NormalState;
                setFormat(nStart, i - nStart + 2, Qt::darkGray);
                i++;
            }
        } 
        else if (nState == InsideCString) {
            if (str.mid(i, 1) == "\"" || str.mid(i, 1) == "\'") {
                if (str.mid(i - 1, 2) != "\\\""  
                    && str.mid(i - 1, 2) != "\\\'"
                   ) {
                    nState = NormalState;
                    setFormat(nStart, i - nStart + 1, Qt::cyan);
                }
            }
        }
        else {
            if (str.mid(i, 2) == "//") {
                setFormat(i, str.length() - i, Qt::darkGray);
                break;
            }
            else if (str.mid(i, 1) == "#") {
                setFormat(i, str.length() - i, Qt::green);
                break;
            }
            else if (str.at(i).isNumber()) {
                setFormat(i, 1, Qt::cyan);
            } 
            else if (str.mid(i, 2) == "/*") {
                nStart = i;
                nState = InsideCStyleComment;
            }
            else if (str.mid(i, 1) == "\"" || str.mid(i, 1) == "\'") {
                nStart = i;
                nState = InsideCString;
            }
            else {
                QString strKeyword = getKeyword(i, str);
                if (!strKeyword.isEmpty()) {
                    setFormat(i, strKeyword.length(), Qt::white);
                    i += strKeyword.length() - 1;
                }
            } 
        }
    }
    if (nState == InsideCStyleComment) {
        setFormat(nStart, str.length() - nStart, Qt::darkGray);
    }
    if (nState == InsideCString) {
        setFormat(nStart, str.length() - nStart, Qt::cyan);
    }
 
    setCurrentBlockState(nState);
}

// ----------------------------------------------------------------------
QString SyntaxHighlighter::getKeyword(int nPos, const QString& str) const
{   
    QString strTemp = "";

    foreach (QString strKeyword, m_lstKeywords) {
        if (str.mid(nPos, strKeyword.length()) == strKeyword) {
            strTemp = strKeyword;
            break;
        }
    }

    return strTemp;
}