text: /*-
   * Copyright 2012-2015 Matthew Endsley
   * All rights reserved
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted providing that the following conditions
   * are met:
   * 1. Redistributions of source code must retain the above copyright
   *    notice, this list of conditions and the following disclaimer.
   * 2. Redistributions in binary form must reproduce the above copyright
   *    notice, this list of conditions and the following disclaimer in the
   *    documentation and/or other materials provided with the distribution.
   *
   * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
   * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
   * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
   * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
   * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
   * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
   * POSSIBILITY OF SUCH DAMAGE.
   */
  
  #ifndef TINYSTL_HASH_BASE_H
  #define TINYSTL_HASH_BASE_H
  
  #include "stddef.h"
  
  namespace tinystl {
      template<typename Key, typename Value>
      struct pair {
          pair();
          pair(const Key& key, const Value& value);
  
          Key first;
          Value second;
      };
  
      template<typename Key, typename Value>
      pair<Key, Value>::pair() {
      }
  
      template<typename Key, typename Value>
      pair<Key, Value>::pair(const Key& key, const Value& value)
          : first(key)
          , second(value)
      {
      }
  
      template<typename Key, typename Value>
      static inline pair<Key, Value> make_pair(const Key& key, const Value& value) {
          return pair<Key, Value>(key, value);
      }
  
      template<typename Key, typename Value>
      struct unordered_hash_node {
          unordered_hash_node(const Key& key, const Value& value);
  
          const Key first;
          Value second;
          unordered_hash_node* next;
          unordered_hash_node* prev;
  
      private:
          unordered_hash_node& operator=(const unordered_hash_node&);
      };
  
      template<typename Key, typename Value>
      unordered_hash_node<Key, Value>::unordered_hash_node(const Key& key, const Value& value)
          : first(key)
          , second(value)
      {
      }
  
      template <typename Key>
      struct unordered_hash_node<Key, void> {
          unordered_hash_node(const Key& key);
  
          const Key first;
          unordered_hash_node* next;
          unordered_hash_node* prev;
  
      private:
          unordered_hash_node& operator=(const unordered_hash_node&);
      };
  
      template<typename Key>
      unordered_hash_node<Key, void>::unordered_hash_node(const Key& key)
          : first(key)
      {
      }
  
      template<typename Key, typename Value>
      static void unordered_hash_node_insert(unordered_hash_node<Key, Value>* node, size_t hash, unordered_hash_node<Key, Value>** buckets, size_t nbuckets) {
          size_t bucket = hash & (nbuckets - 1);
  
          unordered_hash_node<Key, Value>* it = buckets[bucket + 1];
          node->next = it;
          if (it) {
              node->prev = it->prev;
              it->prev = node;
              if (node->prev)
                  node->prev->next = node;
          }
          else {
              size_t newbucket = bucket;
              while (newbucket && !buckets[newbucket])
                  --newbucket;
  
              unordered_hash_node<Key, Value>* prev = buckets[newbucket];
              while (prev && prev->next)
                  prev = prev->next;
  
              node->prev = prev;
              if (prev)
                  prev->next = node;
          }
  
          // propagate node through buckets
          for (; it == buckets[bucket]; --bucket) {
              buckets[bucket] = node;
              if (!bucket)
                  break;
          }
      }
  
      template<typename Key, typename Value>
      static inline void unordered_hash_node_erase(const unordered_hash_node<Key, Value>* where, size_t hash, unordered_hash_node<Key, Value>** buckets, size_t nbuckets) {
          size_t bucket = hash & (nbuckets - 1);
  
          unordered_hash_node<Key, Value>* next = where->next;
          for (; buckets[bucket] == where; --bucket) {
              buckets[bucket] = next;
              if (!bucket)
                  break;
          }
  
          if (where->prev)
          where->prev->next = where->next;
          if (next)
              next->prev = where->prev;
      }
  
      template<typename Node>
      struct unordered_hash_iterator {
          Node* operator->() const;
          Node& operator*() const;
          Node* node;
      };
  
      template<typename Node>
      struct unordered_hash_iterator<const Node> {
          unordered_hash_iterator() {}
          unordered_hash_iterator(unordered_hash_iterator<Node> other)
              : node(other.node)
          {
          }
  
          const Node* operator->() const;
          const Node& operator*() const;
          const Node* node;
      };
  
      template<typename Key>
      struct unordered_hash_iterator<const unordered_hash_node<Key, void> > {
          const Key* operator->() const;
          const Key& operator*() const;
          unordered_hash_node<Key, void>* node;
      };
  
      template<typename LNode, typename RNode>
      static inline bool operator==(const unordered_hash_iterator<LNode>& lhs, const unordered_hash_iterator<RNode>& rhs) {
          return lhs.node == rhs.node;
      }
  
      template<typename LNode, typename RNode>
      static inline bool operator!=(const unordered_hash_iterator<LNode>& lhs, const unordered_hash_iterator<RNode>& rhs) {
          return lhs.node != rhs.node;
      }
  
      template<typename Node>
      static inline void operator++(unordered_hash_iterator<Node>& lhs) {
          lhs.node = lhs.node->next;
      }
  
      template<typename Node>
      inline Node* unordered_hash_iterator<Node>::operator->() const {
          return node;
      }
  
      template<typename Node>
      inline Node& unordered_hash_iterator<Node>::operator*() const {
          return *node;
      }
  
      template<typename Node>
      inline const Node* unordered_hash_iterator<const Node>::operator->() const {
          return node;
      }
  
      template<typename Node>
      inline const Node& unordered_hash_iterator<const Node>::operator*() const {
          return *node;
      }
  
      template<typename Key>
      inline const Key* unordered_hash_iterator<const unordered_hash_node<Key, void> >::operator->() const {
          return &node->first;
      }
  
      template<typename Key>
      inline const Key& unordered_hash_iterator<const unordered_hash_node<Key, void> >::operator*() const {
          return node->first;
      }
  
      template<typename Node, typename Key>
      static inline Node unordered_hash_find(const Key& key, Node* buckets, size_t nbuckets) {
          const size_t bucket = hash(key) & (nbuckets - 2);
          for (Node it = buckets[bucket], end = buckets[bucket + 1]; it != end; it = it->next)
              if (it->first == key)
                  return it;
  
          return 0;
      }
  }
  #endif
  