mapbuilder.h

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// SPDX-FileCopyrightText: Copyright (C) 2021 swift Project Community / Contributors
// SPDX-License-Identifier: GPL-3.0-or-later OR LicenseRef-swift-pilot-client-1
 
 
#ifndef SWIFT_MISC_MAPBUILDER_H
#define SWIFT_MISC_MAPBUILDER_H
 
#include <algorithm>
#include <iterator>
#include <map>
 
#include <QHash>
#include <QList>
#include <QMap>
 
#include "misc/range.h"
 
namespace swift::misc
{
    template <typename K, typename V>
    class CMapBuilder
    {
    public:
        template <typename... Ts>
        void insert(Ts &&...keyAndValue)
        {
            m_list.push_back(std::make_pair(std::forward<Ts>(keyAndValue)...));
        }
 
        bool isEmpty() const { return m_list.isEmpty(); }
 
        operator QMap<K, V>() const & { return convertToMap(sortAndDeduplicate(m_list)); }
        operator QMap<K, V>() && { return convertToMap(sortAndDeduplicate(std::move(m_list))); }
        operator QHash<K, V>() const & { return convertTo<QHash>(sortAndDeduplicate(m_list)); }
        operator QHash<K, V>() && { return convertTo<QHash>(sortAndDeduplicate(std::move(m_list))); }
        operator std::map<K, V>() const & { return convertTo<std::map>(sortAndDeduplicate(m_list)); }
        operator std::map<K, V>() && { return convertTo<std::map>(sortAndDeduplicate(std::move(m_list))); }
 
    private:
        QList<std::pair<K, V>> m_list;
 
        static QList<std::pair<K, V>> sortAndDeduplicate(QList<std::pair<K, V>> list)
        {
            std::sort(list.begin(), list.end(), [](auto &&a, auto &&b) { return std::less<>()(a.first, b.first); });
            list.erase(std::unique(list.begin(), list.end(), [](auto &&a, auto &&b) { return a.first == b.first; }),
                       list.end());
            return list;
        }
 
        template <template <typename...> class C>
        static C<K, V> convertTo(QList<std::pair<K, V>> &&list)
        {
            return C<K, V>(std::make_move_iterator(list.begin()), std::make_move_iterator(list.end()));
        }
 
        static QMap<K, V> convertToMap(QList<std::pair<K, V>> &&list)
        {
            QMap<K, V> map;
            for (auto &pair : makeRange(list).reverse())
            {
                map.insert(map.cbegin(), std::move(pair.first), std::move(pair.second));
            }
            return map;
        }
    };
} // namespace swift::misc
 
#endif // SWIFT_MISC_MAPBUILDER_H