mysort.cpp

#include <QStringList>
#include <QPair>
#include <QVariant>

namespace MySort {

typedef QPair<QList<QVariant>,int> Item; //(int|string)* sequence, value index
typedef bool (*lessThan)(const Item&, const Item&);

template <class T> class Helper {
public:
    Helper(QStringList& keys, QList<T>& values) :  m_values(values) { initKeys(keys); }
    Helper(QList<Item>& keys, QList<T>& values) : m_keys(keys), m_values(values) {}
    void initKeys(const QStringList& keys) {
        int n = keys.size();
        // foreach keys
        for(int i=0;i<n;i++) {
            QString key = keys.at(i);
            QList<QVariant> item;
            QString intPart;
            QString charPart;
            int l = key.size();
            // char-by-char parse
            for (int j=0;j<l;j++) {
                QChar c = key.at(j);
                if (c.isDigit()) {
                    intPart.append(c);
                    if (!charPart.isEmpty()) {
                        item.append(charPart);
                        charPart = QString();
                    }
                } else {
                    charPart.append(c);
                    if (!intPart.isEmpty()) {
                        item.append(intPart.toInt());
                        intPart = QString();
                    }
                }
            }
            // flush
            if (!charPart.isEmpty())
                item.append(charPart);
            if (!intPart.isEmpty())
                item.append(intPart.toInt());
            m_keys.append(Item(item,i));
        }
    }
    void sort(lessThan theLessThan) {
        qSort(m_keys.begin(),m_keys.end(),theLessThan);
        QList<T> m_sortedValues;
        Item item;
        foreach(item,m_keys) {
            int index = item.second;
            m_sortedValues.append(m_values.at(index));
        }
        m_values = m_sortedValues; // hmmm...
    }

private:
    QList<Item> m_keys;
    QList<T>& m_values;
};


bool firstPartLessThan(const Item& item1, const Item& item2) {
    if (item1.first.size()<1)
        return true;
    if (item2.first.size()<1)
        return false;
    const QVariant& v1 = item1.first.at(0);
    const QVariant& v2 = item2.first.at(0);
    if (v1.type() == QVariant::Int && v2.type() == QVariant::Int) {
        return v1.toInt() < v2.toInt();
    } else if (v1.type() == QVariant::String && v2.type() == QVariant::String) {
        return v1.toString() < v2.toString();
    } else if (v1.type() == QVariant::Int) {
        return true;
    } else if (v2.type() == QVariant::Int) {
        return false;
    }
    return false;
}

}

#include <QDebug>
#include <time.h>

int main(int,char**) {

    qsrand(time(0));

    QStringList values;
    QStringList keys;

    QString chars = "01234567890abcdefgh";
    int chars_size = chars.size();

    //generate 20 random strings
    for (int i=0;i<20;i++) {
        QString key;
        // length 5..10
        int l = qrand() % 5 + 5;
        for (int j=0;j<l;j++)
            key.append(chars.at(qrand() % chars_size));
        keys << key;
        values << key;
    }

    MySort::Helper<QString> helper(keys,values);
    helper.sort(&MySort::firstPartLessThan);

    QString value;
    foreach (value,values) {
        qDebug() << value;
    }

}