src/base/orderedset.h

   1 /*
   2  * Bittorrent Client using Qt and libtorrent.
   3  * Copyright (C) 2023  Vladimir Golovnev <glassez@yandex.ru>
   4  * Copyright (C) 2021  Mike Tzou (Chocobo1)
   5  *
   6  * This program is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU General Public License
   8  * as published by the Free Software Foundation; either version 2
   9  * of the License, or (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * along with this program; if not, write to the Free Software
  18  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
  19  *
  20  * In addition, as a special exception, the copyright holders give permission to
  21  * link this program with the OpenSSL project's "OpenSSL" library (or with
  22  * modified versions of it that use the same license as the "OpenSSL" library),
  23  * and distribute the linked executables. You must obey the GNU General Public
  24  * License in all respects for all of the code used other than "OpenSSL".  If you
  25  * modify file(s), you may extend this exception to your version of the file(s),
  26  * but you are not obligated to do so. If you do not wish to do so, delete this
  27  * exception statement from your version.
  28  */
  29
  30 #pragma once
  31
  32 #include <functional>
  33 #include <set>
  34
  35 template <typename T, typename Compare = std::less<T>>
  36 class OrderedSet : public std::set<T, Compare>
  37 {
  38     using ThisType = OrderedSet<T, Compare>;
  39
  40 public:
  41     using BaseType = std::set<T, Compare>;
  42
  43     using key_type = typename BaseType::key_type;
  44     using value_type = typename BaseType::value_type;
  45
  46     using BaseType::BaseType;
  47     using BaseType::operator=;
  48
  49     // The following are custom functions that are in line with Qt API interface, such as `QSet`
  50
  51     int count() const
  52     {
  53         return static_cast<int>(BaseType::size());
  54     }
  55
  56     ThisType &intersect(const ThisType &other)
  57     {
  58         std::erase_if(*this, [&other](const value_type &value) -> bool
  59         {
  60             return !other.contains(value);
  61         });
  62         return *this;
  63     }
  64
  65     bool isEmpty() const
  66     {
  67         return BaseType::empty();
  68     }
  69
  70     bool remove(const key_type &value)
  71     {
  72         return (BaseType::erase(value) > 0);
  73     }
  74
  75     template <typename Set>
  76     ThisType &unite(const Set &other)
  77     {
  78         BaseType::insert(other.cbegin(), other.cend());
  79         return *this;
  80     }
  81
  82     template <typename Set>
  83     ThisType united(const Set &other) const
  84     {
  85         ThisType result = *this;
  86         result.unite(other);
  87         return result;
  88     }
  89 };