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src/tsl/ordered_map.h

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+/**
+ * MIT License
+ *
+ * Copyright (c) 2017 Thibaut Goetghebuer-Planchon <tessil@gmx.com>
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+#ifndef TSL_ORDERED_MAP_H
+#define TSL_ORDERED_MAP_H
+
+#include <cstddef>
+#include <cstdint>
+#include <deque>
+#include <functional>
+#include <initializer_list>
+#include <memory>
+#include <type_traits>
+#include <utility>
+#include <vector>
+
+#include "ordered_hash.h"
+
+namespace tsl {
+
+/**
+ * Implementation of an hash map using open addressing with robin hood with
+ * backshift delete to resolve collisions.
+ *
+ * The particularity of this hash map is that it remembers the order in which
+ * the elements were added and provide a way to access the structure which
+ * stores these values through the 'values_container()' method. The used
+ * container is defined by ValueTypeContainer, by default a std::deque is used
+ * (grows faster) but a std::vector may be used. In this case the map provides a
+ * 'data()' method which give a direct access to the memory used to store the
+ * values (which can be useful to communicate with C API's).
+ *
+ * The Key and T must be copy constructible and/or move constructible. To use
+ * `unordered_erase` they both must be swappable.
+ *
+ * The behaviour of the hash map is undefined if the destructor of Key or T
+ * throws an exception.
+ *
+ * By default the maximum size of a map is limited to 2^32 - 1 values, if needed
+ * this can be changed through the IndexType template parameter. Using an
+ * `uint64_t` will raise this limit to 2^64 - 1 values but each bucket will use
+ * 16 bytes instead of 8 bytes in addition to the space needed to store the
+ * values.
+ *
+ * Iterators invalidation:
+ *  - clear, operator=, reserve, rehash: always invalidate the iterators (also
+ * invalidate end()).
+ *  - insert, emplace, emplace_hint, operator[]: when a std::vector is used as
+ * ValueTypeContainer and if size() < capacity(), only end(). Otherwise all the
+ * iterators are invalidated if an insert occurs.
+ *  - erase, unordered_erase: when a std::vector is used as ValueTypeContainer
+ * invalidate the iterator of the erased element and all the ones after the
+ * erased element (including end()). Otherwise all the iterators are invalidated
+ * if an erase occurs.
+ */
+template <class Key, class T, class Hash = std::hash<Key>,
+          class KeyEqual = std::equal_to<Key>,
+          class Allocator = std::allocator<std::pair<Key, T>>,
+          class ValueTypeContainer = std::deque<std::pair<Key, T>, Allocator>,
+          class IndexType = std::uint_least32_t>
+class ordered_map {
+ private:
+  template <typename U>
+  using has_is_transparent = tsl::detail_ordered_hash::has_is_transparent<U>;
+
+  class KeySelect {
+   public:
+    using key_type = Key;
+
+    const key_type& operator()(
+        const std::pair<Key, T>& key_value) const noexcept {
+      return key_value.first;
+    }
+
+    key_type& operator()(std::pair<Key, T>& key_value) noexcept {
+      return key_value.first;
+    }
+  };
+
+  class ValueSelect {
+   public:
+    using value_type = T;
+
+    const value_type& operator()(
+        const std::pair<Key, T>& key_value) const noexcept {
+      return key_value.second;
+    }
+
+    value_type& operator()(std::pair<Key, T>& key_value) noexcept {
+      return key_value.second;
+    }
+  };
+
+  using ht =
+      detail_ordered_hash::ordered_hash<std::pair<Key, T>, KeySelect,
+                                        ValueSelect, Hash, KeyEqual, Allocator,
+                                        ValueTypeContainer, IndexType>;
+
+ public:
+  using key_type = typename ht::key_type;
+  using mapped_type = T;
+  using value_type = typename ht::value_type;
+  using size_type = typename ht::size_type;
+  using difference_type = typename ht::difference_type;
+  using hasher = typename ht::hasher;
+  using key_equal = typename ht::key_equal;
+  using allocator_type = typename ht::allocator_type;
+  using reference = typename ht::reference;
+  using const_reference = typename ht::const_reference;
+  using pointer = typename ht::pointer;
+  using const_pointer = typename ht::const_pointer;
+  using iterator = typename ht::iterator;
+  using const_iterator = typename ht::const_iterator;
+  using reverse_iterator = typename ht::reverse_iterator;
+  using const_reverse_iterator = typename ht::const_reverse_iterator;
+
+  using values_container_type = typename ht::values_container_type;
+
+  /*
+   * Constructors
+   */
+  ordered_map() : ordered_map(ht::DEFAULT_INIT_BUCKETS_SIZE) {}
+
+  explicit ordered_map(size_type bucket_count, const Hash& hash = Hash(),
+                       const KeyEqual& equal = KeyEqual(),
+                       const Allocator& alloc = Allocator())
+      : m_ht(bucket_count, hash, equal, alloc, ht::DEFAULT_MAX_LOAD_FACTOR) {}
+
+  ordered_map(size_type bucket_count, const Allocator& alloc)
+      : ordered_map(bucket_count, Hash(), KeyEqual(), alloc) {}
+
+  ordered_map(size_type bucket_count, const Hash& hash, const Allocator& alloc)
+      : ordered_map(bucket_count, hash, KeyEqual(), alloc) {}
+
+  explicit ordered_map(const Allocator& alloc)
+      : ordered_map(ht::DEFAULT_INIT_BUCKETS_SIZE, alloc) {}
+
+  template <class InputIt>
+  ordered_map(InputIt first, InputIt last,
+              size_type bucket_count = ht::DEFAULT_INIT_BUCKETS_SIZE,
+              const Hash& hash = Hash(), const KeyEqual& equal = KeyEqual(),
+              const Allocator& alloc = Allocator())
+      : ordered_map(bucket_count, hash, equal, alloc) {
+    insert(first, last);
+  }
+
+  template <class InputIt>
+  ordered_map(InputIt first, InputIt last, size_type bucket_count,
+              const Allocator& alloc)
+      : ordered_map(first, last, bucket_count, Hash(), KeyEqual(), alloc) {}
+
+  template <class InputIt>
+  ordered_map(InputIt first, InputIt last, size_type bucket_count,
+              const Hash& hash, const Allocator& alloc)
+      : ordered_map(first, last, bucket_count, hash, KeyEqual(), alloc) {}
+
+  ordered_map(std::initializer_list<value_type> init,
+              size_type bucket_count = ht::DEFAULT_INIT_BUCKETS_SIZE,
+              const Hash& hash = Hash(), const KeyEqual& equal = KeyEqual(),
+              const Allocator& alloc = Allocator())
+      : ordered_map(init.begin(), init.end(), bucket_count, hash, equal,
+                    alloc) {}
+
+  ordered_map(std::initializer_list<value_type> init, size_type bucket_count,
+              const Allocator& alloc)
+      : ordered_map(init.begin(), init.end(), bucket_count, Hash(), KeyEqual(),
+                    alloc) {}
+
+  ordered_map(std::initializer_list<value_type> init, size_type bucket_count,
+              const Hash& hash, const Allocator& alloc)
+      : ordered_map(init.begin(), init.end(), bucket_count, hash, KeyEqual(),
+                    alloc) {}
+
+  ordered_map& operator=(std::initializer_list<value_type> ilist) {
+    m_ht.clear();
+
+    m_ht.reserve(ilist.size());
+    m_ht.insert(ilist.begin(), ilist.end());
+
+    return *this;
+  }
+
+  allocator_type get_allocator() const { return m_ht.get_allocator(); }
+
+  /*
+   * Iterators
+   */
+  iterator begin() noexcept { return m_ht.begin(); }
+  const_iterator begin() const noexcept { return m_ht.begin(); }
+  const_iterator cbegin() const noexcept { return m_ht.cbegin(); }
+
+  iterator end() noexcept { return m_ht.end(); }
+  const_iterator end() const noexcept { return m_ht.end(); }
+  const_iterator cend() const noexcept { return m_ht.cend(); }
+
+  reverse_iterator rbegin() noexcept { return m_ht.rbegin(); }
+  const_reverse_iterator rbegin() const noexcept { return m_ht.rbegin(); }
+  const_reverse_iterator rcbegin() const noexcept { return m_ht.rcbegin(); }
+
+  reverse_iterator rend() noexcept { return m_ht.rend(); }
+  const_reverse_iterator rend() const noexcept { return m_ht.rend(); }
+  const_reverse_iterator rcend() const noexcept { return m_ht.rcend(); }
+
+  /*
+   * Capacity
+   */
+  bool empty() const noexcept { return m_ht.empty(); }
+  size_type size() const noexcept { return m_ht.size(); }
+  size_type max_size() const noexcept { return m_ht.max_size(); }
+
+  /*
+   * Modifiers
+   */
+  void clear() noexcept { m_ht.clear(); }
+
+  std::pair<iterator, bool> insert(const value_type& value) {
+    return m_ht.insert(value);
+  }
+
+  template <class P, typename std::enable_if<std::is_constructible<
+                         value_type, P&&>::value>::type* = nullptr>
+  std::pair<iterator, bool> insert(P&& value) {
+    return m_ht.emplace(std::forward<P>(value));
+  }
+
+  std::pair<iterator, bool> insert(value_type&& value) {
+    return m_ht.insert(std::move(value));
+  }
+
+  iterator insert(const_iterator hint, const value_type& value) {
+    return m_ht.insert_hint(hint, value);
+  }
+
+  template <class P, typename std::enable_if<std::is_constructible<
+                         value_type, P&&>::value>::type* = nullptr>
+  iterator insert(const_iterator hint, P&& value) {
+    return m_ht.emplace_hint(hint, std::forward<P>(value));
+  }
+
+  iterator insert(const_iterator hint, value_type&& value) {
+    return m_ht.insert_hint(hint, std::move(value));
+  }
+
+  template <class InputIt>
+  void insert(InputIt first, InputIt last) {
+    m_ht.insert(first, last);
+  }
+  void insert(std::initializer_list<value_type> ilist) {
+    m_ht.insert(ilist.begin(), ilist.end());
+  }
+
+  template <class M>
+  std::pair<iterator, bool> insert_or_assign(const key_type& k, M&& obj) {
+    return m_ht.insert_or_assign(k, std::forward<M>(obj));
+  }
+
+  template <class M>
+  std::pair<iterator, bool> insert_or_assign(key_type&& k, M&& obj) {
+    return m_ht.insert_or_assign(std::move(k), std::forward<M>(obj));
+  }
+
+  template <class M>
+  iterator insert_or_assign(const_iterator hint, const key_type& k, M&& obj) {
+    return m_ht.insert_or_assign(hint, k, std::forward<M>(obj));
+  }
+
+  template <class M>
+  iterator insert_or_assign(const_iterator hint, key_type&& k, M&& obj) {
+    return m_ht.insert_or_assign(hint, std::move(k), std::forward<M>(obj));
+  }
+
+  /**
+   * Due to the way elements are stored, emplace will need to move or copy the
+   * key-value once. The method is equivalent to
+   * insert(value_type(std::forward<Args>(args)...));
+   *
+   * Mainly here for compatibility with the std::unordered_map interface.
+   */
+  template <class... Args>
+  std::pair<iterator, bool> emplace(Args&&... args) {
+    return m_ht.emplace(std::forward<Args>(args)...);
+  }
+
+  /**
+   * Due to the way elements are stored, emplace_hint will need to move or copy
+   * the key-value once. The method is equivalent to insert(hint,
+   * value_type(std::forward<Args>(args)...));
+   *
+   * Mainly here for compatibility with the std::unordered_map interface.
+   */
+  template <class... Args>
+  iterator emplace_hint(const_iterator hint, Args&&... args) {
+    return m_ht.emplace_hint(hint, std::forward<Args>(args)...);
+  }
+
+  template <class... Args>
+  std::pair<iterator, bool> try_emplace(const key_type& k, Args&&... args) {
+    return m_ht.try_emplace(k, std::forward<Args>(args)...);
+  }
+
+  template <class... Args>
+  std::pair<iterator, bool> try_emplace(key_type&& k, Args&&... args) {
+    return m_ht.try_emplace(std::move(k), std::forward<Args>(args)...);
+  }
+
+  template <class... Args>
+  iterator try_emplace(const_iterator hint, const key_type& k, Args&&... args) {
+    return m_ht.try_emplace_hint(hint, k, std::forward<Args>(args)...);
+  }
+
+  template <class... Args>
+  iterator try_emplace(const_iterator hint, key_type&& k, Args&&... args) {
+    return m_ht.try_emplace_hint(hint, std::move(k),
+                                 std::forward<Args>(args)...);
+  }
+
+  /**
+   * When erasing an element, the insert order will be preserved and no holes
+   * will be present in the container returned by 'values_container()'.
+   *
+   * The method is in O(bucket_count()), if the order is not important
+   * 'unordered_erase(...)' method is faster with an O(1) average complexity.
+   */
+  iterator erase(iterator pos) { return m_ht.erase(pos); }
+
+  /**
+   * @copydoc erase(iterator pos)
+   */
+  iterator erase(const_iterator pos) { return m_ht.erase(pos); }
+
+  /**
+   * @copydoc erase(iterator pos)
+   */
+  iterator erase(const_iterator first, const_iterator last) {
+    return m_ht.erase(first, last);
+  }
+
+  /**
+   * @copydoc erase(iterator pos)
+   */
+  size_type erase(const key_type& key) { return m_ht.erase(key); }
+
+  /**
+   * @copydoc erase(iterator pos)
+   *
+   * Use the hash value 'precalculated_hash' instead of hashing the key. The
+   * hash value should be the same as hash_function()(key). Useful to speed-up
+   * the lookup to the value if you already have the hash.
+   */
+  size_type erase(const key_type& key, std::size_t precalculated_hash) {
+    return m_ht.erase(key, precalculated_hash);
+  }
+
+  /**
+   * @copydoc erase(iterator pos)
+   *
+   * This overload only participates in the overload resolution if the typedef
+   * KeyEqual::is_transparent exists. If so, K must be hashable and comparable
+   * to Key.
+   */
+  template <
+      class K, class KE = KeyEqual,
+      typename std::enable_if<has_is_transparent<KE>::value>::type* = nullptr>
+  size_type erase(const K& key) {
+    return m_ht.erase(key);
+  }
+
+  /**
+   * @copydoc erase(const key_type& key, std::size_t precalculated_hash)
+   *
+   * This overload only participates in the overload resolution if the typedef
+   * KeyEqual::is_transparent exists. If so, K must be hashable and comparable
+   * to Key.
+   */
+  template <
+      class K, class KE = KeyEqual,
+      typename std::enable_if<has_is_transparent<KE>::value>::type* = nullptr>
+  size_type erase(const K& key, std::size_t precalculated_hash) {
+    return m_ht.erase(key, precalculated_hash);
+  }
+
+  void swap(ordered_map& other) { other.m_ht.swap(m_ht); }
+
+  /*
+   * Lookup
+   */
+  T& at(const Key& key) { return m_ht.at(key); }
+
+  /**
+   * Use the hash value 'precalculated_hash' instead of hashing the key. The
+   * hash value should be the same as hash_function()(key). Useful to speed-up
+   * the lookup if you already have the hash.
+   */
+  T& at(const Key& key, std::size_t precalculated_hash) {
+    return m_ht.at(key, precalculated_hash);
+  }
+
+  const T& at(const Key& key) const { return m_ht.at(key); }
+
+  /**
+   * @copydoc at(const Key& key, std::size_t precalculated_hash)
+   */
+  const T& at(const Key& key, std::size_t precalculated_hash) const {
+    return m_ht.at(key, precalculated_hash);
+  }
+
+  /**
+   * This overload only participates in the overload resolution if the typedef
+   * KeyEqual::is_transparent exists. If so, K must be hashable and comparable
+   * to Key.
+   */
+  template <
+      class K, class KE = KeyEqual,
+      typename std::enable_if<has_is_transparent<KE>::value>::type* = nullptr>
+  T& at(const K& key) {
+    return m_ht.at(key);
+  }
+
+  /**
+   * @copydoc at(const K& key)
+   *
+   * Use the hash value 'precalculated_hash' instead of hashing the key. The
+   * hash value should be the same as hash_function()(key). Useful to speed-up
+   * the lookup if you already have the hash.
+   */
+  template <
+      class K, class KE = KeyEqual,
+      typename std::enable_if<has_is_transparent<KE>::value>::type* = nullptr>
+  T& at(const K& key, std::size_t precalculated_hash) {
+    return m_ht.at(key, precalculated_hash);
+  }
+
+  /**
+   * @copydoc at(const K& key)
+   */
+  template <
+      class K, class KE = KeyEqual,
+      typename std::enable_if<has_is_transparent<KE>::value>::type* = nullptr>
+  const T& at(const K& key) const {
+    return m_ht.at(key);
+  }
+
+  /**
+   * @copydoc at(const K& key, std::size_t precalculated_hash)
+   */
+  template <
+      class K, class KE = KeyEqual,
+      typename std::enable_if<has_is_transparent<KE>::value>::type* = nullptr>
+  const T& at(const K& key, std::size_t precalculated_hash) const {
+    return m_ht.at(key, precalculated_hash);
+  }
+
+  T& operator[](const Key& key) { return m_ht[key]; }
+  T& operator[](Key&& key) { return m_ht[std::move(key)]; }
+
+  size_type count(const Key& key) const { return m_ht.count(key); }
+
+  /**
+   * Use the hash value 'precalculated_hash' instead of hashing the key. The
+   * hash value should be the same as hash_function()(key). Useful to speed-up
+   * the lookup if you already have the hash.
+   */
+  size_type count(const Key& key, std::size_t precalculated_hash) const {
+    return m_ht.count(key, precalculated_hash);
+  }
+
+  /**
+   * This overload only participates in the overload resolution if the typedef
+   * KeyEqual::is_transparent exists. If so, K must be hashable and comparable
+   * to Key.
+   */
+  template <
+      class K, class KE = KeyEqual,
+      typename std::enable_if<has_is_transparent<KE>::value>::type* = nullptr>
+  size_type count(const K& key) const {
+    return m_ht.count(key);
+  }
+
+  /**
+   * @copydoc count(const K& key) const
+   *
+   * Use the hash value 'precalculated_hash' instead of hashing the key. The
+   * hash value should be the same as hash_function()(key). Useful to speed-up
+   * the lookup if you already have the hash.
+   */
+  template <
+      class K, class KE = KeyEqual,
+      typename std::enable_if<has_is_transparent<KE>::value>::type* = nullptr>
+  size_type count(const K& key, std::size_t precalculated_hash) const {
+    return m_ht.count(key, precalculated_hash);
+  }
+
+  iterator find(const Key& key) { return m_ht.find(key); }
+
+  /**
+   * Use the hash value 'precalculated_hash' instead of hashing the key. The
+   * hash value should be the same as hash_function()(key). Useful to speed-up
+   * the lookup if you already have the hash.
+   */
+  iterator find(const Key& key, std::size_t precalculated_hash) {
+    return m_ht.find(key, precalculated_hash);
+  }
+
+  const_iterator find(const Key& key) const { return m_ht.find(key); }
+
+  /**
+   * @copydoc find(const Key& key, std::size_t precalculated_hash)
+   */
+  const_iterator find(const Key& key, std::size_t precalculated_hash) const {
+    return m_ht.find(key, precalculated_hash);
+  }
+
+  /**
+   * This overload only participates in the overload resolution if the typedef
+   * KeyEqual::is_transparent exists. If so, K must be hashable and comparable
+   * to Key.
+   */
+  template <
+      class K, class KE = KeyEqual,
+      typename std::enable_if<has_is_transparent<KE>::value>::type* = nullptr>
+  iterator find(const K& key) {
+    return m_ht.find(key);
+  }
+
+  /**
+   * @copydoc find(const K& key)
+   *
+   * Use the hash value 'precalculated_hash' instead of hashing the key. The
+   * hash value should be the same as hash_function()(key). Useful to speed-up
+   * the lookup if you already have the hash.
+   */
+  template <
+      class K, class KE = KeyEqual,
+      typename std::enable_if<has_is_transparent<KE>::value>::type* = nullptr>
+  iterator find(const K& key, std::size_t precalculated_hash) {
+    return m_ht.find(key, precalculated_hash);
+  }
+
+  /**
+   * @copydoc find(const K& key)
+   */
+  template <
+      class K, class KE = KeyEqual,
+      typename std::enable_if<has_is_transparent<KE>::value>::type* = nullptr>
+  const_iterator find(const K& key) const {
+    return m_ht.find(key);
+  }
+
+  /**
+   * @copydoc find(const K& key)
+   *
+   * Use the hash value 'precalculated_hash' instead of hashing the key. The
+   * hash value should be the same as hash_function()(key). Useful to speed-up
+   * the lookup if you already have the hash.
+   */
+  template <
+      class K, class KE = KeyEqual,
+      typename std::enable_if<has_is_transparent<KE>::value>::type* = nullptr>
+  const_iterator find(const K& key, std::size_t precalculated_hash) const {
+    return m_ht.find(key, precalculated_hash);
+  }
+
+  bool contains(const Key& key) const { return m_ht.contains(key); }
+
+  /**
+   * Use the hash value 'precalculated_hash' instead of hashing the key. The
+   * hash value should be the same as hash_function()(key). Useful to speed-up
+   * the lookup if you already have the hash.
+   */
+  bool contains(const Key& key, std::size_t precalculated_hash) const {
+    return m_ht.contains(key, precalculated_hash);
+  }
+
+  /**
+   * This overload only participates in the overload resolution if the typedef
+   * KeyEqual::is_transparent exists. If so, K must be hashable and comparable
+   * to Key.
+   */
+  template <
+      class K, class KE = KeyEqual,
+      typename std::enable_if<has_is_transparent<KE>::value>::type* = nullptr>
+  bool contains(const K& key) const {
+    return m_ht.contains(key);
+  }
+
+  /**
+   * @copydoc contains(const K& key) const
+   *
+   * Use the hash value 'precalculated_hash' instead of hashing the key. The
+   * hash value should be the same as hash_function()(key). Useful to speed-up
+   * the lookup if you already have the hash.
+   */
+  template <
+      class K, class KE = KeyEqual,
+      typename std::enable_if<has_is_transparent<KE>::value>::type* = nullptr>
+  bool contains(const K& key, std::size_t precalculated_hash) const {
+    return m_ht.contains(key, precalculated_hash);
+  }
+
+  std::pair<iterator, iterator> equal_range(const Key& key) {
+    return m_ht.equal_range(key);
+  }
+
+  /**
+   * Use the hash value 'precalculated_hash' instead of hashing the key. The
+   * hash value should be the same as hash_function()(key). Useful to speed-up
+   * the lookup if you already have the hash.
+   */
+  std::pair<iterator, iterator> equal_range(const Key& key,
+                                            std::size_t precalculated_hash) {
+    return m_ht.equal_range(key, precalculated_hash);
+  }
+
+  std::pair<const_iterator, const_iterator> equal_range(const Key& key) const {
+    return m_ht.equal_range(key);
+  }
+
+  /**
+   * @copydoc equal_range(const Key& key, std::size_t precalculated_hash)
+   */
+  std::pair<const_iterator, const_iterator> equal_range(
+      const Key& key, std::size_t precalculated_hash) const {
+    return m_ht.equal_range(key, precalculated_hash);
+  }
+
+  /**
+   * This overload only participates in the overload resolution if the typedef
+   * KeyEqual::is_transparent exists. If so, K must be hashable and comparable
+   * to Key.
+   */
+  template <
+      class K, class KE = KeyEqual,
+      typename std::enable_if<has_is_transparent<KE>::value>::type* = nullptr>
+  std::pair<iterator, iterator> equal_range(const K& key) {
+    return m_ht.equal_range(key);
+  }
+
+  /**
+   * @copydoc equal_range(const K& key)
+   *
+   * Use the hash value 'precalculated_hash' instead of hashing the key. The
+   * hash value should be the same as hash_function()(key). Useful to speed-up
+   * the lookup if you already have the hash.
+   */
+  template <
+      class K, class KE = KeyEqual,
+      typename std::enable_if<has_is_transparent<KE>::value>::type* = nullptr>
+  std::pair<iterator, iterator> equal_range(const K& key,
+                                            std::size_t precalculated_hash) {
+    return m_ht.equal_range(key, precalculated_hash);
+  }
+
+  /**
+   * @copydoc equal_range(const K& key)
+   */
+  template <
+      class K, class KE = KeyEqual,
+      typename std::enable_if<has_is_transparent<KE>::value>::type* = nullptr>
+  std::pair<const_iterator, const_iterator> equal_range(const K& key) const {
+    return m_ht.equal_range(key);
+  }
+
+  /**
+   * @copydoc equal_range(const K& key, std::size_t precalculated_hash)
+   */
+  template <
+      class K, class KE = KeyEqual,
+      typename std::enable_if<has_is_transparent<KE>::value>::type* = nullptr>
+  std::pair<const_iterator, const_iterator> equal_range(
+      const K& key, std::size_t precalculated_hash) const {
+    return m_ht.equal_range(key, precalculated_hash);
+  }
+
+  /*
+   * Bucket interface
+   */
+  size_type bucket_count() const { return m_ht.bucket_count(); }
+  size_type max_bucket_count() const { return m_ht.max_bucket_count(); }
+
+  /*
+   * Hash policy
+   */
+  float load_factor() const { return m_ht.load_factor(); }
+  float max_load_factor() const { return m_ht.max_load_factor(); }
+  void max_load_factor(float ml) { m_ht.max_load_factor(ml); }
+
+  void rehash(size_type count) { m_ht.rehash(count); }
+  void reserve(size_type count) { m_ht.reserve(count); }
+
+  /*
+   * Observers
+   */
+  hasher hash_function() const { return m_ht.hash_function(); }
+  key_equal key_eq() const { return m_ht.key_eq(); }
+
+  /*
+   * Other
+   */
+
+  /**
+   * Convert a const_iterator to an iterator.
+   */
+  iterator mutable_iterator(const_iterator pos) {
+    return m_ht.mutable_iterator(pos);
+  }
+
+  /**
+   * Requires index <= size().
+   *
+   * Return an iterator to the element at index. Return end() if index ==
+   * size().
+   */
+  iterator nth(size_type index) { return m_ht.nth(index); }
+
+  /**
+   * @copydoc nth(size_type index)
+   */
+  const_iterator nth(size_type index) const { return m_ht.nth(index); }
+
+  /**
+   * Return const_reference to the first element. Requires the container to not
+   * be empty.
+   */
+  const_reference front() const { return m_ht.front(); }
+
+  /**
+   * Return const_reference to the last element. Requires the container to not
+   * be empty.
+   */
+  const_reference back() const { return m_ht.back(); }
+
+  /**
+   * Only available if ValueTypeContainer is a std::vector. Same as calling
+   * 'values_container().data()'.
+   */
+  template <class U = values_container_type,
+            typename std::enable_if<
+                tsl::detail_ordered_hash::is_vector<U>::value>::type* = nullptr>
+  const typename values_container_type::value_type* data() const noexcept {
+    return m_ht.data();
+  }
+
+  /**
+   * Return the container in which the values are stored. The values are in the
+   * same order as the insertion order and are contiguous in the structure, no
+   * holes (size() == values_container().size()).
+   */
+  const values_container_type& values_container() const noexcept {
+    return m_ht.values_container();
+  }
+
+  /**
+   * Release the container in which the values are stored.
+   *
+   * The map is empty after this operation.
+   */
+  values_container_type release() { return m_ht.release(); }
+
+  template <class U = values_container_type,
+            typename std::enable_if<
+                tsl::detail_ordered_hash::is_vector<U>::value>::type* = nullptr>
+  size_type capacity() const noexcept {
+    return m_ht.capacity();
+  }
+
+  void shrink_to_fit() { m_ht.shrink_to_fit(); }
+
+  /**
+   * Insert the value before pos shifting all the elements on the right of pos
+   * (including pos) one position to the right.
+   *
+   * O(bucket_count()) runtime complexity.
+   */
+  std::pair<iterator, bool> insert_at_position(const_iterator pos,
+                                               const value_type& value) {
+    return m_ht.insert_at_position(pos, value);
+  }
+
+  /**
+   * @copydoc insert_at_position(const_iterator pos, const value_type& value)
+   */
+  std::pair<iterator, bool> insert_at_position(const_iterator pos,
+                                               value_type&& value) {
+    return m_ht.insert_at_position(pos, std::move(value));
+  }
+
+  /**
+   * @copydoc insert_at_position(const_iterator pos, const value_type& value)
+   *
+   * Same as insert_at_position(pos, value_type(std::forward<Args>(args)...),
+   * mainly here for coherence.
+   */
+  template <class... Args>
+  std::pair<iterator, bool> emplace_at_position(const_iterator pos,
+                                                Args&&... args) {
+    return m_ht.emplace_at_position(pos, std::forward<Args>(args)...);
+  }
+
+  /**
+   * @copydoc insert_at_position(const_iterator pos, const value_type& value)
+   */
+  template <class... Args>
+  std::pair<iterator, bool> try_emplace_at_position(const_iterator pos,
+                                                    const key_type& k,
+                                                    Args&&... args) {
+    return m_ht.try_emplace_at_position(pos, k, std::forward<Args>(args)...);
+  }
+
+  /**
+   * @copydoc insert_at_position(const_iterator pos, const value_type& value)
+   */
+  template <class... Args>
+  std::pair<iterator, bool> try_emplace_at_position(const_iterator pos,
+                                                    key_type&& k,
+                                                    Args&&... args) {
+    return m_ht.try_emplace_at_position(pos, std::move(k),
+                                        std::forward<Args>(args)...);
+  }
+
+  void pop_back() { m_ht.pop_back(); }
+
+  /**
+   * Faster erase operation with an O(1) average complexity but it doesn't
+   * preserve the insertion order.
+   *
+   * If an erasure occurs, the last element of the map will take the place of
+   * the erased element.
+   */
+  iterator unordered_erase(iterator pos) { return m_ht.unordered_erase(pos); }
+
+  /**
+   * @copydoc unordered_erase(iterator pos)
+   */
+  iterator unordered_erase(const_iterator pos) {
+    return m_ht.unordered_erase(pos);
+  }
+
+  /**
+   * @copydoc unordered_erase(iterator pos)
+   */
+  size_type unordered_erase(const key_type& key) {
+    return m_ht.unordered_erase(key);
+  }
+
+  /**
+   * @copydoc unordered_erase(iterator pos)
+   *
+   * Use the hash value 'precalculated_hash' instead of hashing the key. The
+   * hash value should be the same as hash_function()(key). Useful to speed-up
+   * the lookup if you already have the hash.
+   */
+  size_type unordered_erase(const key_type& key,
+                            std::size_t precalculated_hash) {
+    return m_ht.unordered_erase(key, precalculated_hash);
+  }
+
+  /**
+   * @copydoc unordered_erase(iterator pos)
+   *
+   * This overload only participates in the overload resolution if the typedef
+   * KeyEqual::is_transparent exists. If so, K must be hashable and comparable
+   * to Key.
+   */
+  template <
+      class K, class KE = KeyEqual,
+      typename std::enable_if<has_is_transparent<KE>::value>::type* = nullptr>
+  size_type unordered_erase(const K& key) {
+    return m_ht.unordered_erase(key);
+  }
+
+  /**
+   * @copydoc unordered_erase(const K& key)
+   *
+   * Use the hash value 'precalculated_hash' instead of hashing the key. The
+   * hash value should be the same as hash_function()(key). Useful to speed-up
+   * the lookup if you already have the hash.
+   */
+  template <
+      class K, class KE = KeyEqual,
+      typename std::enable_if<has_is_transparent<KE>::value>::type* = nullptr>
+  size_type unordered_erase(const K& key, std::size_t precalculated_hash) {
+    return m_ht.unordered_erase(key, precalculated_hash);
+  }
+
+  /**
+   * Serialize the map through the `serializer` parameter.
+   *
+   * The `serializer` parameter must be a function object that supports the
+   * following call:
+   *  - `template<typename U> void operator()(const U& value);` where the types
+   * `std::uint64_t`, `float` and `std::pair<Key, T>` must be supported for U.
+   *
+   * The implementation leaves binary compatibility (endianness, IEEE 754 for
+   * floats, ...) of the types it serializes in the hands of the `Serializer`
+   * function object if compatibility is required.
+   */
+  template <class Serializer>
+  void serialize(Serializer& serializer) const {
+    m_ht.serialize(serializer);
+  }
+
+  /**
+   * Deserialize a previously serialized map through the `deserializer`
+   * parameter.
+   *
+   * The `deserializer` parameter must be a function object that supports the
+   * following calls:
+   *  - `template<typename U> U operator()();` where the types `std::uint64_t`,
+   * `float` and `std::pair<Key, T>` must be supported for U.
+   *
+   * If the deserialized hash map type is hash compatible with the serialized
+   * map, the deserialization process can be sped up by setting
+   * `hash_compatible` to true. To be hash compatible, the Hash and KeyEqual
+   * must behave the same way than the ones used on the serialized map. The
+   * `std::size_t` must also be of the same size as the one on the platform used
+   * to serialize the map, the same apply for `IndexType`. If these criteria are
+   * not met, the behaviour is undefined with `hash_compatible` sets to true.
+   *
+   * The behaviour is undefined if the type `Key` and `T` of the `ordered_map`
+   * are not the same as the types used during serialization.
+   *
+   * The implementation leaves binary compatibility (endianness, IEEE 754 for
+   * floats, size of int, ...) of the types it deserializes in the hands of the
+   * `Deserializer` function object if compatibility is required.
+   */
+  template <class Deserializer>
+  static ordered_map deserialize(Deserializer& deserializer,
+                                 bool hash_compatible = false) {
+    ordered_map map(0);
+    map.m_ht.deserialize(deserializer, hash_compatible);
+
+    return map;
+  }
+
+  friend bool operator==(const ordered_map& lhs, const ordered_map& rhs) {
+    return lhs.m_ht == rhs.m_ht;
+  }
+  friend bool operator!=(const ordered_map& lhs, const ordered_map& rhs) {
+    return lhs.m_ht != rhs.m_ht;
+  }
+  friend bool operator<(const ordered_map& lhs, const ordered_map& rhs) {
+    return lhs.m_ht < rhs.m_ht;
+  }
+  friend bool operator<=(const ordered_map& lhs, const ordered_map& rhs) {
+    return lhs.m_ht <= rhs.m_ht;
+  }
+  friend bool operator>(const ordered_map& lhs, const ordered_map& rhs) {
+    return lhs.m_ht > rhs.m_ht;
+  }
+  friend bool operator>=(const ordered_map& lhs, const ordered_map& rhs) {
+    return lhs.m_ht >= rhs.m_ht;
+  }
+
+  friend void swap(ordered_map& lhs, ordered_map& rhs) { lhs.swap(rhs); }
+
+ private:
+  ht m_ht;
+};
+
+}  // end namespace tsl
+
+#endif

src/tsl/ordered_set.h

@@ -0,0 +1,817 @@
+/**
+ * MIT License
+ *
+ * Copyright (c) 2017 Thibaut Goetghebuer-Planchon <tessil@gmx.com>
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+#ifndef TSL_ORDERED_SET_H
+#define TSL_ORDERED_SET_H
+
+#include <cstddef>
+#include <cstdint>
+#include <deque>
+#include <functional>
+#include <initializer_list>
+#include <memory>
+#include <type_traits>
+#include <utility>
+#include <vector>
+
+#include "ordered_hash.h"
+
+namespace tsl {
+
+/**
+ * Implementation of an hash set using open addressing with robin hood with
+ * backshift delete to resolve collisions.
+ *
+ * The particularity of this hash set is that it remembers the order in which
+ * the elements were added and provide a way to access the structure which
+ * stores these values through the 'values_container()' method. The used
+ * container is defined by ValueTypeContainer, by default a std::deque is used
+ * (grows faster) but a std::vector may be used. In this case the set provides a
+ * 'data()' method which give a direct access to the memory used to store the
+ * values (which can be useful to communicate with C API's).
+ *
+ * The Key must be copy constructible and/or move constructible. To use
+ * `unordered_erase` it also must be swappable.
+ *
+ * The behaviour of the hash set is undefined if the destructor of Key throws an
+ * exception.
+ *
+ * By default the maximum size of a set is limited to 2^32 - 1 values, if needed
+ * this can be changed through the IndexType template parameter. Using an
+ * `uint64_t` will raise this limit to 2^64 - 1 values but each bucket will use
+ * 16 bytes instead of 8 bytes in addition to the space needed to store the
+ * values.
+ *
+ * Iterators invalidation:
+ *  - clear, operator=, reserve, rehash: always invalidate the iterators (also
+ * invalidate end()).
+ *  - insert, emplace, emplace_hint, operator[]: when a std::vector is used as
+ * ValueTypeContainer and if size() < capacity(), only end(). Otherwise all the
+ * iterators are invalidated if an insert occurs.
+ *  - erase, unordered_erase: when a std::vector is used as ValueTypeContainer
+ * invalidate the iterator of the erased element and all the ones after the
+ * erased element (including end()). Otherwise all the iterators are invalidated
+ * if an erase occurs.
+ */
+template <class Key, class Hash = std::hash<Key>,
+          class KeyEqual = std::equal_to<Key>,
+          class Allocator = std::allocator<Key>,
+          class ValueTypeContainer = std::deque<Key, Allocator>,
+          class IndexType = std::uint_least32_t>
+class ordered_set {
+ private:
+  template <typename U>
+  using has_is_transparent = tsl::detail_ordered_hash::has_is_transparent<U>;
+
+  class KeySelect {
+   public:
+    using key_type = Key;
+
+    const key_type& operator()(const Key& key) const noexcept { return key; }
+
+    key_type& operator()(Key& key) noexcept { return key; }
+  };
+
+  using ht = detail_ordered_hash::ordered_hash<Key, KeySelect, void, Hash,
+                                               KeyEqual, Allocator,
+                                               ValueTypeContainer, IndexType>;
+
+ public:
+  using key_type = typename ht::key_type;
+  using value_type = typename ht::value_type;
+  using size_type = typename ht::size_type;
+  using difference_type = typename ht::difference_type;
+  using hasher = typename ht::hasher;
+  using key_equal = typename ht::key_equal;
+  using allocator_type = typename ht::allocator_type;
+  using reference = typename ht::reference;
+  using const_reference = typename ht::const_reference;
+  using pointer = typename ht::pointer;
+  using const_pointer = typename ht::const_pointer;
+  using iterator = typename ht::iterator;
+  using const_iterator = typename ht::const_iterator;
+  using reverse_iterator = typename ht::reverse_iterator;
+  using const_reverse_iterator = typename ht::const_reverse_iterator;
+
+  using values_container_type = typename ht::values_container_type;
+
+  /*
+   * Constructors
+   */
+  ordered_set() : ordered_set(ht::DEFAULT_INIT_BUCKETS_SIZE) {}
+
+  explicit ordered_set(size_type bucket_count, const Hash& hash = Hash(),
+                       const KeyEqual& equal = KeyEqual(),
+                       const Allocator& alloc = Allocator())
+      : m_ht(bucket_count, hash, equal, alloc, ht::DEFAULT_MAX_LOAD_FACTOR) {}
+
+  ordered_set(size_type bucket_count, const Allocator& alloc)
+      : ordered_set(bucket_count, Hash(), KeyEqual(), alloc) {}
+
+  ordered_set(size_type bucket_count, const Hash& hash, const Allocator& alloc)
+      : ordered_set(bucket_count, hash, KeyEqual(), alloc) {}
+
+  explicit ordered_set(const Allocator& alloc)
+      : ordered_set(ht::DEFAULT_INIT_BUCKETS_SIZE, alloc) {}
+
+  template <class InputIt>
+  ordered_set(InputIt first, InputIt last,
+              size_type bucket_count = ht::DEFAULT_INIT_BUCKETS_SIZE,
+              const Hash& hash = Hash(), const KeyEqual& equal = KeyEqual(),
+              const Allocator& alloc = Allocator())
+      : ordered_set(bucket_count, hash, equal, alloc) {
+    insert(first, last);
+  }
+
+  template <class InputIt>
+  ordered_set(InputIt first, InputIt last, size_type bucket_count,
+              const Allocator& alloc)
+      : ordered_set(first, last, bucket_count, Hash(), KeyEqual(), alloc) {}
+
+  template <class InputIt>
+  ordered_set(InputIt first, InputIt last, size_type bucket_count,
+              const Hash& hash, const Allocator& alloc)
+      : ordered_set(first, last, bucket_count, hash, KeyEqual(), alloc) {}
+
+  ordered_set(std::initializer_list<value_type> init,
+              size_type bucket_count = ht::DEFAULT_INIT_BUCKETS_SIZE,
+              const Hash& hash = Hash(), const KeyEqual& equal = KeyEqual(),
+              const Allocator& alloc = Allocator())
+      : ordered_set(init.begin(), init.end(), bucket_count, hash, equal,
+                    alloc) {}
+
+  ordered_set(std::initializer_list<value_type> init, size_type bucket_count,
+              const Allocator& alloc)
+      : ordered_set(init.begin(), init.end(), bucket_count, Hash(), KeyEqual(),
+                    alloc) {}
+
+  ordered_set(std::initializer_list<value_type> init, size_type bucket_count,
+              const Hash& hash, const Allocator& alloc)
+      : ordered_set(init.begin(), init.end(), bucket_count, hash, KeyEqual(),
+                    alloc) {}
+
+  ordered_set& operator=(std::initializer_list<value_type> ilist) {
+    m_ht.clear();
+
+    m_ht.reserve(ilist.size());
+    m_ht.insert(ilist.begin(), ilist.end());
+
+    return *this;
+  }
+
+  allocator_type get_allocator() const { return m_ht.get_allocator(); }
+
+  /*
+   * Iterators
+   */
+  iterator begin() noexcept { return m_ht.begin(); }
+  const_iterator begin() const noexcept { return m_ht.begin(); }
+  const_iterator cbegin() const noexcept { return m_ht.cbegin(); }
+
+  iterator end() noexcept { return m_ht.end(); }
+  const_iterator end() const noexcept { return m_ht.end(); }
+  const_iterator cend() const noexcept { return m_ht.cend(); }
+
+  reverse_iterator rbegin() noexcept { return m_ht.rbegin(); }
+  const_reverse_iterator rbegin() const noexcept { return m_ht.rbegin(); }
+  const_reverse_iterator rcbegin() const noexcept { return m_ht.rcbegin(); }
+
+  reverse_iterator rend() noexcept { return m_ht.rend(); }
+  const_reverse_iterator rend() const noexcept { return m_ht.rend(); }
+  const_reverse_iterator rcend() const noexcept { return m_ht.rcend(); }
+
+  /*
+   * Capacity
+   */
+  bool empty() const noexcept { return m_ht.empty(); }
+  size_type size() const noexcept { return m_ht.size(); }
+  size_type max_size() const noexcept { return m_ht.max_size(); }
+
+  /*
+   * Modifiers
+   */
+  void clear() noexcept { m_ht.clear(); }
+
+  std::pair<iterator, bool> insert(const value_type& value) {
+    return m_ht.insert(value);
+  }
+  std::pair<iterator, bool> insert(value_type&& value) {
+    return m_ht.insert(std::move(value));
+  }
+
+  iterator insert(const_iterator hint, const value_type& value) {
+    return m_ht.insert_hint(hint, value);
+  }
+
+  iterator insert(const_iterator hint, value_type&& value) {
+    return m_ht.insert_hint(hint, std::move(value));
+  }
+
+  template <class InputIt>
+  void insert(InputIt first, InputIt last) {
+    m_ht.insert(first, last);
+  }
+  void insert(std::initializer_list<value_type> ilist) {
+    m_ht.insert(ilist.begin(), ilist.end());
+  }
+
+  /**
+   * Due to the way elements are stored, emplace will need to move or copy the
+   * key-value once. The method is equivalent to
+   * insert(value_type(std::forward<Args>(args)...));
+   *
+   * Mainly here for compatibility with the std::unordered_map interface.
+   */
+  template <class... Args>
+  std::pair<iterator, bool> emplace(Args&&... args) {
+    return m_ht.emplace(std::forward<Args>(args)...);
+  }
+
+  /**
+   * Due to the way elements are stored, emplace_hint will need to move or copy
+   * the key-value once. The method is equivalent to insert(hint,
+   * value_type(std::forward<Args>(args)...));
+   *
+   * Mainly here for compatibility with the std::unordered_map interface.
+   */
+  template <class... Args>
+  iterator emplace_hint(const_iterator hint, Args&&... args) {
+    return m_ht.emplace_hint(hint, std::forward<Args>(args)...);
+  }
+
+  /**
+   * When erasing an element, the insert order will be preserved and no holes
+   * will be present in the container returned by 'values_container()'.
+   *
+   * The method is in O(bucket_count()), if the order is not important
+   * 'unordered_erase(...)' method is faster with an O(1) average complexity.
+   */
+  iterator erase(iterator pos) { return m_ht.erase(pos); }
+
+  /**
+   * @copydoc erase(iterator pos)
+   */
+  iterator erase(const_iterator pos) { return m_ht.erase(pos); }
+
+  /**
+   * @copydoc erase(iterator pos)
+   */
+  iterator erase(const_iterator first, const_iterator last) {
+    return m_ht.erase(first, last);
+  }
+
+  /**
+   * @copydoc erase(iterator pos)
+   */
+  size_type erase(const key_type& key) { return m_ht.erase(key); }
+
+  /**
+   * @copydoc erase(iterator pos)
+   *
+   * Use the hash value 'precalculated_hash' instead of hashing the key. The
+   * hash value should be the same as hash_function()(key). Useful to speed-up
+   * the lookup to the value if you already have the hash.
+   */
+  size_type erase(const key_type& key, std::size_t precalculated_hash) {
+    return m_ht.erase(key, precalculated_hash);
+  }
+
+  /**
+   * @copydoc erase(iterator pos)
+   *
+   * This overload only participates in the overload resolution if the typedef
+   * KeyEqual::is_transparent exists. If so, K must be hashable and comparable
+   * to Key.
+   */
+  template <
+      class K, class KE = KeyEqual,
+      typename std::enable_if<has_is_transparent<KE>::value>::type* = nullptr>
+  size_type erase(const K& key) {
+    return m_ht.erase(key);
+  }
+
+  /**
+   * @copydoc erase(const key_type& key, std::size_t precalculated_hash)
+   *
+   * This overload only participates in the overload resolution if the typedef
+   * KeyEqual::is_transparent exists. If so, K must be hashable and comparable
+   * to Key.
+   */
+  template <
+      class K, class KE = KeyEqual,
+      typename std::enable_if<has_is_transparent<KE>::value>::type* = nullptr>
+  size_type erase(const K& key, std::size_t precalculated_hash) {
+    return m_ht.erase(key, precalculated_hash);
+  }
+
+  void swap(ordered_set& other) { other.m_ht.swap(m_ht); }
+
+  /*
+   * Lookup
+   */
+  size_type count(const Key& key) const { return m_ht.count(key); }
+
+  /**
+   * Use the hash value 'precalculated_hash' instead of hashing the key. The
+   * hash value should be the same as hash_function()(key). Useful to speed-up
+   * the lookup if you already have the hash.
+   */
+  size_type count(const Key& key, std::size_t precalculated_hash) const {
+    return m_ht.count(key, precalculated_hash);
+  }
+
+  /**
+   * This overload only participates in the overload resolution if the typedef
+   * KeyEqual::is_transparent exists. If so, K must be hashable and comparable
+   * to Key.
+   */
+  template <
+      class K, class KE = KeyEqual,
+      typename std::enable_if<has_is_transparent<KE>::value>::type* = nullptr>
+  size_type count(const K& key) const {
+    return m_ht.count(key);
+  }
+
+  /**
+   * @copydoc count(const K& key) const
+   *
+   * Use the hash value 'precalculated_hash' instead of hashing the key. The
+   * hash value should be the same as hash_function()(key). Useful to speed-up
+   * the lookup if you already have the hash.
+   */
+  template <
+      class K, class KE = KeyEqual,
+      typename std::enable_if<has_is_transparent<KE>::value>::type* = nullptr>
+  size_type count(const K& key, std::size_t precalculated_hash) const {
+    return m_ht.count(key, precalculated_hash);
+  }
+
+  iterator find(const Key& key) { return m_ht.find(key); }
+
+  /**
+   * Use the hash value 'precalculated_hash' instead of hashing the key. The
+   * hash value should be the same as hash_function()(key). Useful to speed-up
+   * the lookup if you already have the hash.
+   */
+  iterator find(const Key& key, std::size_t precalculated_hash) {
+    return m_ht.find(key, precalculated_hash);
+  }
+
+  const_iterator find(const Key& key) const { return m_ht.find(key); }
+
+  /**
+   * @copydoc find(const Key& key, std::size_t precalculated_hash)
+   */
+  const_iterator find(const Key& key, std::size_t precalculated_hash) const {
+    return m_ht.find(key, precalculated_hash);
+  }
+
+  /**
+   * This overload only participates in the overload resolution if the typedef
+   * KeyEqual::is_transparent exists. If so, K must be hashable and comparable
+   * to Key.
+   */
+  template <
+      class K, class KE = KeyEqual,
+      typename std::enable_if<has_is_transparent<KE>::value>::type* = nullptr>
+  iterator find(const K& key) {
+    return m_ht.find(key);
+  }
+
+  /**
+   * @copydoc find(const K& key)
+   *
+   * Use the hash value 'precalculated_hash' instead of hashing the key. The
+   * hash value should be the same as hash_function()(key). Useful to speed-up
+   * the lookup if you already have the hash.
+   */
+  template <
+      class K, class KE = KeyEqual,
+      typename std::enable_if<has_is_transparent<KE>::value>::type* = nullptr>
+  iterator find(const K& key, std::size_t precalculated_hash) {
+    return m_ht.find(key, precalculated_hash);
+  }
+
+  /**
+   * @copydoc find(const K& key)
+   */
+  template <
+      class K, class KE = KeyEqual,
+      typename std::enable_if<has_is_transparent<KE>::value>::type* = nullptr>
+  const_iterator find(const K& key) const {
+    return m_ht.find(key);
+  }
+
+  /**
+   * @copydoc find(const K& key)
+   *
+   * Use the hash value 'precalculated_hash' instead of hashing the key. The
+   * hash value should be the same as hash_function()(key). Useful to speed-up
+   * the lookup if you already have the hash.
+   */
+  template <
+      class K, class KE = KeyEqual,
+      typename std::enable_if<has_is_transparent<KE>::value>::type* = nullptr>
+  const_iterator find(const K& key, std::size_t precalculated_hash) const {
+    return m_ht.find(key, precalculated_hash);
+  }
+
+  bool contains(const Key& key) const { return m_ht.contains(key); }
+
+  /**
+   * Use the hash value 'precalculated_hash' instead of hashing the key. The
+   * hash value should be the same as hash_function()(key). Useful to speed-up
+   * the lookup if you already have the hash.
+   */
+  bool contains(const Key& key, std::size_t precalculated_hash) const {
+    return m_ht.contains(key, precalculated_hash);
+  }
+
+  /**
+   * This overload only participates in the overload resolution if the typedef
+   * KeyEqual::is_transparent exists. If so, K must be hashable and comparable
+   * to Key.
+   */
+  template <
+      class K, class KE = KeyEqual,
+      typename std::enable_if<has_is_transparent<KE>::value>::type* = nullptr>
+  bool contains(const K& key) const {
+    return m_ht.contains(key);
+  }
+
+  /**
+   * @copydoc contains(const K& key) const
+   *
+   * Use the hash value 'precalculated_hash' instead of hashing the key. The
+   * hash value should be the same as hash_function()(key). Useful to speed-up
+   * the lookup if you already have the hash.
+   */
+  template <
+      class K, class KE = KeyEqual,
+      typename std::enable_if<has_is_transparent<KE>::value>::type* = nullptr>
+  bool contains(const K& key, std::size_t precalculated_hash) const {
+    return m_ht.contains(key, precalculated_hash);
+  }
+
+  std::pair<iterator, iterator> equal_range(const Key& key) {
+    return m_ht.equal_range(key);
+  }
+
+  /**
+   * Use the hash value 'precalculated_hash' instead of hashing the key. The
+   * hash value should be the same as hash_function()(key). Useful to speed-up
+   * the lookup if you already have the hash.
+   */
+  std::pair<iterator, iterator> equal_range(const Key& key,
+                                            std::size_t precalculated_hash) {
+    return m_ht.equal_range(key, precalculated_hash);
+  }
+
+  std::pair<const_iterator, const_iterator> equal_range(const Key& key) const {
+    return m_ht.equal_range(key);
+  }
+
+  /**
+   * @copydoc equal_range(const Key& key, std::size_t precalculated_hash)
+   */
+  std::pair<const_iterator, const_iterator> equal_range(
+      const Key& key, std::size_t precalculated_hash) const {
+    return m_ht.equal_range(key, precalculated_hash);
+  }
+
+  /**
+   * This overload only participates in the overload resolution if the typedef
+   * KeyEqual::is_transparent exists. If so, K must be hashable and comparable
+   * to Key.
+   */
+  template <
+      class K, class KE = KeyEqual,
+      typename std::enable_if<has_is_transparent<KE>::value>::type* = nullptr>
+  std::pair<iterator, iterator> equal_range(const K& key) {
+    return m_ht.equal_range(key);
+  }
+
+  /**
+   * @copydoc equal_range(const K& key)
+   *
+   * Use the hash value 'precalculated_hash' instead of hashing the key. The
+   * hash value should be the same as hash_function()(key). Useful to speed-up
+   * the lookup if you already have the hash.
+   */
+  template <
+      class K, class KE = KeyEqual,
+      typename std::enable_if<has_is_transparent<KE>::value>::type* = nullptr>
+  std::pair<iterator, iterator> equal_range(const K& key,
+                                            std::size_t precalculated_hash) {
+    return m_ht.equal_range(key, precalculated_hash);
+  }
+
+  /**
+   * @copydoc equal_range(const K& key)
+   */
+  template <
+      class K, class KE = KeyEqual,
+      typename std::enable_if<has_is_transparent<KE>::value>::type* = nullptr>
+  std::pair<const_iterator, const_iterator> equal_range(const K& key) const {
+    return m_ht.equal_range(key);
+  }
+
+  /**
+   * @copydoc equal_range(const K& key, std::size_t precalculated_hash)
+   */
+  template <
+      class K, class KE = KeyEqual,
+      typename std::enable_if<has_is_transparent<KE>::value>::type* = nullptr>
+  std::pair<const_iterator, const_iterator> equal_range(
+      const K& key, std::size_t precalculated_hash) const {
+    return m_ht.equal_range(key, precalculated_hash);
+  }
+
+  /*
+   * Bucket interface
+   */
+  size_type bucket_count() const { return m_ht.bucket_count(); }
+  size_type max_bucket_count() const { return m_ht.max_bucket_count(); }
+
+  /*
+   *  Hash policy
+   */
+  float load_factor() const { return m_ht.load_factor(); }
+  float max_load_factor() const { return m_ht.max_load_factor(); }
+  void max_load_factor(float ml) { m_ht.max_load_factor(ml); }
+
+  void rehash(size_type count) { m_ht.rehash(count); }
+  void reserve(size_type count) { m_ht.reserve(count); }
+
+  /*
+   * Observers
+   */
+  hasher hash_function() const { return m_ht.hash_function(); }
+  key_equal key_eq() const { return m_ht.key_eq(); }
+
+  /*
+   * Other
+   */
+
+  /**
+   * Convert a const_iterator to an iterator.
+   */
+  iterator mutable_iterator(const_iterator pos) {
+    return m_ht.mutable_iterator(pos);
+  }
+
+  /**
+   * Requires index <= size().
+   *
+   * Return an iterator to the element at index. Return end() if index ==
+   * size().
+   */
+  iterator nth(size_type index) { return m_ht.nth(index); }
+
+  /**
+   * @copydoc nth(size_type index)
+   */
+  const_iterator nth(size_type index) const { return m_ht.nth(index); }
+
+  /**
+   * Return const_reference to the first element. Requires the container to not
+   * be empty.
+   */
+  const_reference front() const { return m_ht.front(); }
+
+  /**
+   * Return const_reference to the last element. Requires the container to not
+   * be empty.
+   */
+  const_reference back() const { return m_ht.back(); }
+
+  /**
+   * Only available if ValueTypeContainer is a std::vector. Same as calling
+   * 'values_container().data()'.
+   */
+  template <class U = values_container_type,
+            typename std::enable_if<
+                tsl::detail_ordered_hash::is_vector<U>::value>::type* = nullptr>
+  const typename values_container_type::value_type* data() const noexcept {
+    return m_ht.data();
+  }
+
+  /**
+   * Return the container in which the values are stored. The values are in the
+   * same order as the insertion order and are contiguous in the structure, no
+   * holes (size() == values_container().size()).
+   */
+  const values_container_type& values_container() const noexcept {
+    return m_ht.values_container();
+  }
+
+  /**
+   * Release the container in which the values are stored.
+   *
+   * The set is empty after this operation.
+   */
+  values_container_type release() { return m_ht.release(); }
+
+  template <class U = values_container_type,
+            typename std::enable_if<
+                tsl::detail_ordered_hash::is_vector<U>::value>::type* = nullptr>
+  size_type capacity() const noexcept {
+    return m_ht.capacity();
+  }
+
+  void shrink_to_fit() { m_ht.shrink_to_fit(); }
+
+  /**
+   * Insert the value before pos shifting all the elements on the right of pos
+   * (including pos) one position to the right.
+   *
+   * O(bucket_count()) runtime complexity.
+   */
+  std::pair<iterator, bool> insert_at_position(const_iterator pos,
+                                               const value_type& value) {
+    return m_ht.insert_at_position(pos, value);
+  }
+
+  /**
+   * @copydoc insert_at_position(const_iterator pos, const value_type& value)
+   */
+  std::pair<iterator, bool> insert_at_position(const_iterator pos,
+                                               value_type&& value) {
+    return m_ht.insert_at_position(pos, std::move(value));
+  }
+
+  /**
+   * @copydoc insert_at_position(const_iterator pos, const value_type& value)
+   *
+   * Same as insert_at_position(pos, value_type(std::forward<Args>(args)...),
+   * mainly here for coherence.
+   */
+  template <class... Args>
+  std::pair<iterator, bool> emplace_at_position(const_iterator pos,
+                                                Args&&... args) {
+    return m_ht.emplace_at_position(pos, std::forward<Args>(args)...);
+  }
+
+  void pop_back() { m_ht.pop_back(); }
+
+  /**
+   * Faster erase operation with an O(1) average complexity but it doesn't
+   * preserve the insertion order.
+   *
+   * If an erasure occurs, the last element of the map will take the place of
+   * the erased element.
+   */
+  iterator unordered_erase(iterator pos) { return m_ht.unordered_erase(pos); }
+
+  /**
+   * @copydoc unordered_erase(iterator pos)
+   */
+  iterator unordered_erase(const_iterator pos) {
+    return m_ht.unordered_erase(pos);
+  }
+
+  /**
+   * @copydoc unordered_erase(iterator pos)
+   */
+  size_type unordered_erase(const key_type& key) {
+    return m_ht.unordered_erase(key);
+  }
+
+  /**
+   * @copydoc unordered_erase(iterator pos)
+   *
+   * Use the hash value 'precalculated_hash' instead of hashing the key. The
+   * hash value should be the same as hash_function()(key). Useful to speed-up
+   * the lookup if you already have the hash.
+   */
+  size_type unordered_erase(const key_type& key,
+                            std::size_t precalculated_hash) {
+    return m_ht.unordered_erase(key, precalculated_hash);
+  }
+
+  /**
+   * @copydoc unordered_erase(iterator pos)
+   *
+   * This overload only participates in the overload resolution if the typedef
+   * KeyEqual::is_transparent exists. If so, K must be hashable and comparable
+   * to Key.
+   */
+  template <
+      class K, class KE = KeyEqual,
+      typename std::enable_if<has_is_transparent<KE>::value>::type* = nullptr>
+  size_type unordered_erase(const K& key) {
+    return m_ht.unordered_erase(key);
+  }
+
+  /**
+   * @copydoc unordered_erase(const K& key)
+   *
+   * Use the hash value 'precalculated_hash' instead of hashing the key. The
+   * hash value should be the same as hash_function()(key). Useful to speed-up
+   * the lookup if you already have the hash.
+   */
+  template <
+      class K, class KE = KeyEqual,
+      typename std::enable_if<has_is_transparent<KE>::value>::type* = nullptr>
+  size_type unordered_erase(const K& key, std::size_t precalculated_hash) {
+    return m_ht.unordered_erase(key, precalculated_hash);
+  }
+
+  /**
+   * Serialize the set through the `serializer` parameter.
+   *
+   * The `serializer` parameter must be a function object that supports the
+   * following call:
+   *  - `void operator()(const U& value);` where the types `std::uint64_t`,
+   * `float` and `Key` must be supported for U.
+   *
+   * The implementation leaves binary compatibility (endianness, IEEE 754 for
+   * floats, ...) of the types it serializes in the hands of the `Serializer`
+   * function object if compatibility is required.
+   */
+  template <class Serializer>
+  void serialize(Serializer& serializer) const {
+    m_ht.serialize(serializer);
+  }
+
+  /**
+   * Deserialize a previously serialized set through the `deserializer`
+   * parameter.
+   *
+   * The `deserializer` parameter must be a function object that supports the
+   * following calls:
+   *  - `template<typename U> U operator()();` where the types `std::uint64_t`,
+   * `float` and `Key` must be supported for U.
+   *
+   * If the deserialized hash set type is hash compatible with the serialized
+   * set, the deserialization process can be sped up by setting
+   * `hash_compatible` to true. To be hash compatible, the Hash and KeyEqual
+   * must behave the same way than the ones used on the serialized map. The
+   * `std::size_t` must also be of the same size as the one on the platform used
+   * to serialize the map, the same apply for `IndexType`. If these criteria are
+   * not met, the behaviour is undefined with `hash_compatible` sets to true.
+   *
+   * The behaviour is undefined if the type `Key` of the `ordered_set` is not
+   * the same as the type used during serialization.
+   *
+   * The implementation leaves binary compatibility (endianness, IEEE 754 for
+   * floats, size of int, ...) of the types it deserializes in the hands of the
+   * `Deserializer` function object if compatibility is required.
+   */
+  template <class Deserializer>
+  static ordered_set deserialize(Deserializer& deserializer,
+                                 bool hash_compatible = false) {
+    ordered_set set(0);
+    set.m_ht.deserialize(deserializer, hash_compatible);
+
+    return set;
+  }
+
+  friend bool operator==(const ordered_set& lhs, const ordered_set& rhs) {
+    return lhs.m_ht == rhs.m_ht;
+  }
+  friend bool operator!=(const ordered_set& lhs, const ordered_set& rhs) {
+    return lhs.m_ht != rhs.m_ht;
+  }
+  friend bool operator<(const ordered_set& lhs, const ordered_set& rhs) {
+    return lhs.m_ht < rhs.m_ht;
+  }
+  friend bool operator<=(const ordered_set& lhs, const ordered_set& rhs) {
+    return lhs.m_ht <= rhs.m_ht;
+  }
+  friend bool operator>(const ordered_set& lhs, const ordered_set& rhs) {
+    return lhs.m_ht > rhs.m_ht;
+  }
+  friend bool operator>=(const ordered_set& lhs, const ordered_set& rhs) {
+    return lhs.m_ht >= rhs.m_ht;
+  }
+
+  friend void swap(ordered_set& lhs, ordered_set& rhs) { lhs.swap(rhs); }
+
+ private:
+  ht m_ht;
+};
+
+}  // end namespace tsl
+
+#endif