src/base/orderedset.h

   1 /*
   2  * Bittorrent Client using Qt and libtorrent.
   3  * Copyright (C) 2021  Mike Tzou (Chocobo1)
   4  *
   5  * This program is free software; you can redistribute it and/or
   6  * modify it under the terms of the GNU General Public License
   7  * as published by the Free Software Foundation; either version 2
   8  * of the License, or (at your option) any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License
  16  * along with this program; if not, write to the Free Software
  17  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
  18  *
  19  * In addition, as a special exception, the copyright holders give permission to
  20  * link this program with the OpenSSL project's "OpenSSL" library (or with
  21  * modified versions of it that use the same license as the "OpenSSL" library),
  22  * and distribute the linked executables. You must obey the GNU General Public
  23  * License in all respects for all of the code used other than "OpenSSL".  If you
  24  * modify file(s), you may extend this exception to your version of the file(s),
  25  * but you are not obligated to do so. If you do not wish to do so, delete this
  26  * exception statement from your version.
  27  */
  28
  29 #pragma once
  30
  31 #include <functional>
  32 #include <set>
  33 #include <type_traits>
  34
  35 #include "algorithm.h"
  36
  37 template <typename T, typename Compare = std::less<T>>
  38 class OrderedSet : public std::set<T, Compare>
  39 {
  40     using ThisType = OrderedSet<T, Compare>;
  41
  42 public:
  43     using BaseType = std::set<T, Compare>;
  44
  45     using key_type = typename BaseType::key_type;
  46     using value_type = typename BaseType::value_type;
  47
  48     using BaseType::BaseType;
  49     using BaseType::operator=;
  50
  51     // The following are custom functions that are in line with Qt API interface, such as `QSet`
  52
  53 #if __cplusplus < 202002L
  54     bool contains(const key_type &value) const
  55     {
  56         return (BaseType::find(value) != BaseType::cend());
  57     }
  58 #endif
  59
  60     int count() const
  61     {
  62         return static_cast<int>(BaseType::size());
  63     }
  64
  65     ThisType &intersect(const ThisType &other)
  66     {
  67         Algorithm::removeIf(*this, [&other](const value_type &value) -> bool
  68         {
  69             return !other.contains(value);
  70         });
  71         return *this;
  72     }
  73
  74     bool isEmpty() const
  75     {
  76         return BaseType::empty();
  77     }
  78
  79     template <typename std::enable_if_t<std::is_same_v<value_type, QString>, int> = 0>
  80     QString join(const QString &separator) const
  81     {
  82         auto iter = BaseType::cbegin();
  83         if (iter == BaseType::cend())
  84             return {};
  85
  86         QString ret = *iter;
  87         ++iter;
  88
  89         while (iter != BaseType::cend())
  90         {
  91             ret.push_back(separator + *iter);
  92             ++iter;
  93         }
  94
  95         return ret;
  96     }
  97
  98     bool remove(const key_type &value)
  99     {
 100         return (BaseType::erase(value) > 0);
 101     }
 102
 103     ThisType &unite(const ThisType &other)
 104     {
 105         BaseType::insert(other.cbegin(), other.cend());
 106         return *this;
 107     }
 108 };