File indexing completed on 2024-11-24 05:07:24

 /**
  * 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_ROBIN_SET_H
 #define TSL_ROBIN_SET_H
 
 #include <cstddef>
 #include <functional>
 #include <initializer_list>
 #include <memory>
 #include <type_traits>
 #include <utility>
 
 #include "robin_hash.h"
 
 namespace tsl {
 
 /**
  * Implementation of a hash set using open-addressing and the robin hood hashing
  * algorithm with backward shift deletion.
  *
  * For operations modifying the hash set (insert, erase, rehash, ...), the
  * strong exception guarantee is only guaranteed when the expression
  * `std::is_nothrow_swappable<Key>::value &&
  * std::is_nothrow_move_constructible<Key>::value` is true, otherwise if an
  * exception is thrown during the swap or the move, the hash set may end up in a
  * undefined state. Per the standard a `Key` with a noexcept copy constructor
  * and no move constructor also satisfies the
  * `std::is_nothrow_move_constructible<Key>::value` criterion (and will thus
  * guarantee the strong exception for the set).
  *
  * When `StoreHash` is true, 32 bits of the hash are stored alongside the
  * values. It can improve the performance during lookups if the `KeyEqual`
  * function takes time (or engenders a cache-miss for example) as we then
  * compare the stored hashes before comparing the keys. When
  * `tsl::rh::power_of_two_growth_policy` is used as `GrowthPolicy`, it may also
  * speed-up the rehash process as we can avoid to recalculate the hash. When it
  * is detected that storing the hash will not incur any memory penalty due to
  * alignment (i.e. `sizeof(tsl::detail_robin_hash::bucket_entry<ValueType,
  * true>) == sizeof(tsl::detail_robin_hash::bucket_entry<ValueType, false>)`)
  * and `tsl::rh::power_of_two_growth_policy` is used, the hash will be stored
  * even if `StoreHash` is false so that we can speed-up the rehash (but it will
  * not be used on lookups unless `StoreHash` is true).
  *
  * `GrowthPolicy` defines how the set grows and consequently how a hash value is
  * mapped to a bucket. By default the set uses
  * `tsl::rh::power_of_two_growth_policy`. This policy keeps the number of
  * buckets to a power of two and uses a mask to set the hash to a bucket instead
  * of the slow modulo. Other growth policies are available and you may define
  * your own growth policy, check `tsl::rh::power_of_two_growth_policy` for the
  * interface.
  *
  * `Key` must be swappable.
  *
  * `Key` must be copy and/or move constructible.
  *
  * If the destructor of `Key` throws an exception, the behaviour of the class is
  * undefined.
  *
  * Iterators invalidation:
  *  - clear, operator=, reserve, rehash: always invalidate the iterators.
  *  - insert, emplace, emplace_hint, operator[]: if there is an effective
  * insert, invalidate the iterators.
  *  - erase: always invalidate the iterators.
  */
 template <class Key, class Hash = std::hash<Key>,
           class KeyEqual = std::equal_to<Key>,
           class Allocator = std::allocator<Key>, bool StoreHash = false,
           class GrowthPolicy = tsl::rh::power_of_two_growth_policy<2>>
 class robin_set {
  private:
   template <typename U>
   using has_is_transparent = tsl::detail_robin_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_robin_hash::robin_hash<Key, KeySelect, void, Hash, KeyEqual,
                                            Allocator, StoreHash, GrowthPolicy>;
 
  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;
 
   /*
    * Constructors
    */
   robin_set() : robin_set(ht::DEFAULT_INIT_BUCKETS_SIZE) {}
 
   explicit robin_set(size_type bucket_count, const Hash& hash = Hash(),
                      const KeyEqual& equal = KeyEqual(),
                      const Allocator& alloc = Allocator())
       : m_ht(bucket_count, hash, equal, alloc) {}
 
   robin_set(size_type bucket_count, const Allocator& alloc)
       : robin_set(bucket_count, Hash(), KeyEqual(), alloc) {}
 
   robin_set(size_type bucket_count, const Hash& hash, const Allocator& alloc)
       : robin_set(bucket_count, hash, KeyEqual(), alloc) {}
 
   explicit robin_set(const Allocator& alloc)
       : robin_set(ht::DEFAULT_INIT_BUCKETS_SIZE, alloc) {}
 
   template <class InputIt>
   robin_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())
       : robin_set(bucket_count, hash, equal, alloc) {
     insert(first, last);
   }
 
   template <class InputIt>
   robin_set(InputIt first, InputIt last, size_type bucket_count,
             const Allocator& alloc)
       : robin_set(first, last, bucket_count, Hash(), KeyEqual(), alloc) {}
 
   template <class InputIt>
   robin_set(InputIt first, InputIt last, size_type bucket_count,
             const Hash& hash, const Allocator& alloc)
       : robin_set(first, last, bucket_count, hash, KeyEqual(), alloc) {}
 
   robin_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())
       : robin_set(init.begin(), init.end(), bucket_count, hash, equal, alloc) {}
 
   robin_set(std::initializer_list<value_type> init, size_type bucket_count,
             const Allocator& alloc)
       : robin_set(init.begin(), init.end(), bucket_count, Hash(), KeyEqual(),
                   alloc) {}
 
   robin_set(std::initializer_list<value_type> init, size_type bucket_count,
             const Hash& hash, const Allocator& alloc)
       : robin_set(init.begin(), init.end(), bucket_count, hash, KeyEqual(),
                   alloc) {}
 
   robin_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(); }
 
   /*
    * 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)...);
   }
 
   iterator erase(iterator pos) { return m_ht.erase(pos); }
   iterator erase(const_iterator pos) { return m_ht.erase(pos); }
   iterator erase(const_iterator first, const_iterator last) {
     return m_ht.erase(first, last);
   }
   size_type erase(const key_type& key) { return m_ht.erase(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 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);
   }
 
   /**
    * 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 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 to the value 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 erase(const K& key, std::size_t precalculated_hash) {
     return m_ht.erase(key, precalculated_hash);
   }
 
   void swap(robin_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 min_load_factor() const { return m_ht.min_load_factor(); }
   float max_load_factor() const { return m_ht.max_load_factor(); }
 
   /**
    * Set the `min_load_factor` to `ml`. When the `load_factor` of the set goes
    * below `min_load_factor` after some erase operations, the set will be
    * shrunk when an insertion occurs. The erase method itself never shrinks
    * the set.
    *
    * The default value of `min_load_factor` is 0.0f, the set never shrinks by
    * default.
    */
   void min_load_factor(float ml) { m_ht.min_load_factor(ml); }
   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);
   }
 
   friend bool operator==(const robin_set& lhs, const robin_set& rhs) {
     if (lhs.size() != rhs.size()) {
       return false;
     }
 
     for (const auto& element_lhs : lhs) {
       const auto it_element_rhs = rhs.find(element_lhs);
       if (it_element_rhs == rhs.cend()) {
         return false;
       }
     }
 
     return true;
   }
 
   /**
    * Serialize the set 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::int16_t`, `std::uint32_t`, `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 call:
    *  - `template<typename U> U operator()();` where the types `std::int16_t`,
    * `std::uint32_t`, `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, KeyEqual and
    * GrowthPolicy must behave the same way than the ones used on the serialized
    * set and the StoreHash must have the same value. The `std::size_t` must also
    * be of the same size as the one on the platform used to serialize the set.
    * 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 `robin_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 robin_set deserialize(Deserializer& deserializer,
                                bool hash_compatible = false) {
     robin_set set(0);
     set.m_ht.deserialize(deserializer, hash_compatible);
 
     return set;
   }
 
   friend bool operator!=(const robin_set& lhs, const robin_set& rhs) {
     return !operator==(lhs, rhs);
   }
 
   friend void swap(robin_set& lhs, robin_set& rhs) { lhs.swap(rhs); }
 
  private:
   ht m_ht;
 };
 
 /**
  * Same as `tsl::robin_set<Key, Hash, KeyEqual, Allocator, StoreHash,
  * tsl::rh::prime_growth_policy>`.
  */
 template <class Key, class Hash = std::hash<Key>,
           class KeyEqual = std::equal_to<Key>,
           class Allocator = std::allocator<Key>, bool StoreHash = false>
 using robin_pg_set = robin_set<Key, Hash, KeyEqual, Allocator, StoreHash,
                                tsl::rh::prime_growth_policy>;
 
 }  // end namespace tsl
 
 #endif