mirror of
https://github.com/TrinityCore/TrinityCore.git
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245 lines
8.8 KiB
C++
245 lines
8.8 KiB
C++
/*
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* Copyright (C) 2008-2017 TrinityCore <http://www.trinitycore.org/>
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License as published by the
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* Free Software Foundation; either version 2 of the License, or (at your
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* option) any later version.
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*
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* This program is distributed in the hope that it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
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* more details.
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*
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* You should have received a copy of the GNU General Public License along
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* with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#ifndef TRINITY_CONTAINERS_H
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#define TRINITY_CONTAINERS_H
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#include "Define.h"
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#include "Random.h"
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#include <algorithm>
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#include <utility>
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#include <vector>
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namespace Trinity
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{
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template<class T>
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constexpr inline T* AddressOrSelf(T* ptr)
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{
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return ptr;
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}
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template<class T>
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constexpr inline T* AddressOrSelf(T& not_ptr)
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{
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return std::addressof(not_ptr);
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}
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namespace Containers
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{
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// replace with std::size in C++17
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template<class C>
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constexpr inline std::size_t Size(C const& container)
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{
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return container.size();
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}
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template<class T, std::size_t size>
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constexpr inline std::size_t Size(T const(&)[size]) noexcept
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{
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return size;
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}
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// resizes <container> to have at most <requestedSize> elements
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// if it has more than <requestedSize> elements, the elements to keep are selected randomly
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template<class C>
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void RandomResize(C& container, std::size_t requestedSize)
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{
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static_assert(std::is_base_of<std::forward_iterator_tag, typename std::iterator_traits<typename C::iterator>::iterator_category>::value, "Invalid container passed to Trinity::Containers::RandomResize");
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if (Size(container) <= requestedSize)
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return;
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auto keepIt = std::begin(container), curIt = std::begin(container);
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uint32 elementsToKeep = requestedSize, elementsToProcess = Size(container);
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while (elementsToProcess)
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{
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// this element has chance (elementsToKeep / elementsToProcess) of being kept
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if (urand(1, elementsToProcess) <= elementsToKeep)
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{
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*keepIt = std::move(*curIt);
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++keepIt;
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--elementsToKeep;
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}
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++curIt;
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--elementsToProcess;
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}
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container.erase(keepIt, std::end(container));
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}
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template<class C, class Predicate>
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void RandomResize(C& container, Predicate&& predicate, std::size_t requestedSize)
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{
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//! First use predicate filter
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C containerCopy;
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std::copy_if(std::begin(container), std::end(container), std::inserter(containerCopy, std::end(containerCopy)), predicate);
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if (requestedSize)
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RandomResize(containerCopy, requestedSize);
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container = std::move(containerCopy);
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}
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/*
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* Select a random element from a container.
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*
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* Note: container cannot be empty
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*/
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template<class C>
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inline auto SelectRandomContainerElement(C const& container) -> typename std::add_const<decltype(*std::begin(container))>::type&
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{
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auto it = std::begin(container);
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std::advance(it, urand(0, uint32(Size(container)) - 1));
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return *it;
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}
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/*
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* Select a random element from a container where each element has a different chance to be selected.
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*
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* @param container Container to select an element from
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* @param weights Chances of each element to be selected, must be in the same order as elements in container.
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* Caller is responsible for checking that sum of all weights is greater than 0.
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*
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* Note: container cannot be empty
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*/
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template<class C>
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inline auto SelectRandomWeightedContainerElement(C const& container, std::vector<double> weights) -> decltype(std::begin(container))
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{
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auto it = std::begin(container);
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std::advance(it, urandweighted(weights.size(), weights.data()));
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return it;
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}
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/*
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* Select a random element from a container where each element has a different chance to be selected.
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*
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* @param container Container to select an element from
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* @param weightExtractor Function retrieving chance of each element in container, expected to take an element of the container and returning a double
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*
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* Note: container cannot be empty
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*/
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template<class C, class Fn>
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auto SelectRandomWeightedContainerElement(C const& container, Fn weightExtractor) -> decltype(std::begin(container))
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{
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std::vector<double> weights;
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weights.reserve(Size(container));
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double weightSum = 0.0;
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for (auto& val : container)
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{
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double weight = weightExtractor(val);
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weights.push_back(weight);
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weightSum += weight;
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}
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if (weightSum <= 0.0)
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weights.assign(Size(container), 1.0);
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return SelectRandomWeightedContainerElement(container, weights);
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}
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/**
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* @fn void Trinity::Containers::RandomShuffle(C& container)
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*
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* @brief Reorder the elements of the container randomly.
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*
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* @param container Container to reorder
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*/
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template<class C>
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inline void RandomShuffle(C& container)
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{
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std::shuffle(std::begin(container), std::end(container), SFMTEngine::Instance());
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}
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/**
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* @fn bool Trinity::Containers::Intersects(Iterator first1, Iterator last1, Iterator first2, Iterator last2)
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*
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* @brief Checks if two SORTED containers have a common element
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*
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* @param first1 Iterator pointing to start of the first container
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* @param last1 Iterator pointing to end of the first container
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* @param first2 Iterator pointing to start of the second container
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* @param last2 Iterator pointing to end of the second container
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*
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* @return true if containers have a common element, false otherwise.
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*/
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template<class Iterator1, class Iterator2>
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bool Intersects(Iterator1 first1, Iterator1 last1, Iterator2 first2, Iterator2 last2)
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{
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while (first1 != last1 && first2 != last2)
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{
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if (*first1 < *first2)
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++first1;
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else if (*first2 < *first1)
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++first2;
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else
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return true;
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}
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return false;
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}
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/**
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* Returns a pointer to mapped value (or the value itself if map stores pointers)
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*/
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template<class M>
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inline auto MapGetValuePtr(M& map, typename M::key_type const& key) -> decltype(AddressOrSelf(map.find(key)->second))
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{
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auto itr = map.find(key);
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return itr != map.end() ? AddressOrSelf(itr->second) : nullptr;
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}
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/**
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* @class IteratorPair
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*
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* @brief Utility class to enable range for loop syntax for multimap.equal_range uses
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*/
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template<class iterator>
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class IteratorPair
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{
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public:
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IteratorPair() : _iterators() { }
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IteratorPair(iterator first, iterator second) : _iterators(first, second) { }
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IteratorPair(std::pair<iterator, iterator> iterators) : _iterators(iterators) { }
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iterator begin() const { return _iterators.first; }
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iterator end() const { return _iterators.second; }
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private:
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std::pair<iterator, iterator> _iterators;
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};
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template<class M>
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inline auto MapEqualRange(M& map, typename M::key_type const& key) -> IteratorPair<decltype(map.begin())>
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{
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return { map.equal_range(key) };
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}
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template<class K, class V, template<class, class, class...> class M, class... Rest>
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void MultimapErasePair(M<K, V, Rest...>& multimap, K const& key, V const& value)
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{
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auto range = multimap.equal_range(key);
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for (auto itr = range.first; itr != range.second;)
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{
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if (itr->second == value)
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itr = multimap.erase(itr);
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else
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++itr;
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}
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}
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}
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//! namespace Containers
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}
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//! namespace Trinity
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#endif //! #ifdef TRINITY_CONTAINERS_H
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