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  • Algorithm
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  • 🐧 How Linux Works (notes)
  • 🐧 Linux Kernel Comments (notes)
  • 🐧 Linux Kernel Development (notes)
  • 🐤 μc/OS-II Source Code (notes)
  • ☕ Understanding the JVM (notes)
  • ⛸️ Redis Implementation (notes)
  • 🗜️ Understanding Nginx (notes)
  • ⚙️ Netty in Action (notes)
  • ☁️ Spring Microservices (notes)
  • ⚒️ The Annotated STL Sources (notes)
  • ☕ Java Development Kit 8
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  • ⚒️ The Annotated STL Sources
    • Chapter 1 - STL 概论与版本简介

      • Chapter 1 - STL 概论与版本简介
    • Chapter 2 - 空间分配器 allocator

      • Chapter 2.1 - SGI 空间分配器
      • Chapter 2.2 - SGI 特殊的空间分配器
      • Chapter 2.3 - 内存基本处理工具
    • Chapter 3 - 迭代器概念与 traits 编程方法

      • Chapter 3.1-3.5 - 迭代器设计思维
      • Chapter 3.6 - iterator 源代码完整重列
      • Chapter 3.7 - SGI STL 的私房菜:__type_traits
    • Chapter 4 - 序列式容器

      • Chapter 4.2 - vector
      • Chapter 4.3 - list
      • Chapter 4.4 - deque
      • Chapter 4.5 - stack
      • Chapter 4.6 - queue
      • Chapter 4.7 - heap
      • Chapter 4.8 - priority_queue
      • Chapter 4.9 - slist
    • Chapter 5 - 关联式容器

      • Chapter 5.2 - RB-Tree
      • Chapter 5.3 - set & multiset
      • Chapter 5.3 - map & multimap
      • Chapter 5.7 - hashtable
      • Chapter 5.8 - hash_set
      • Chapter 5.8 - hash_map
      • Chapter 5.10 - hash_multiset
      • Chapter 5.11 - hash_multimap
    • Chapter 6 - 算法

      • Chapter 6.1-6.3 - 数值算法
      • Chapter 6.4 - 基本算法
      • Chapter 6.5 - set 相关算法
      • Chapter 6.7.1 - 数据处理算法
      • Chapter 6.7.2 - lower_bound
      • Chapter 6.7.3 - upper_bound
      • Chapter 6.7.5 - permutation
      • Chapter 6.7.7 - random_shuffle
      • Chapter 6.7.8 - partial_sort / partial_sort_copy
      • Chapter 6.7.9 - sort
      • Chapter 6.7.12 - nth_element
    • Chapter 7 - 仿函数 functors

      • Chapter 7 - 仿函数 functors
    • Chapter 8 - 适配器

      • Chapter 8.1-8.2 - Container Adapters
      • Chapter 8.3 - Iterator Adapters
      • Chapter 8.4 - Function Adapters

Chapter 5.8 - hash_set

Created by : Mr Dk.

2021 / 04 / 06 23:31

Nanjing, Jiangsu, China


SGI STL 的 hash_set 使用 hashtable 作为底层机制。几乎所有 hash_set 的操作都是转而调用 hashtable 的操作。hash_set 和 set 的区别是 无序性。

template <class _Value,
          class _HashFcn  __STL_DEPENDENT_DEFAULT_TMPL(hash<_Value>),
          class _EqualKey __STL_DEPENDENT_DEFAULT_TMPL(equal_to<_Value>),
          class _Alloc =  __STL_DEFAULT_ALLOCATOR(_Value) >
class hash_set;

底层结构为 hashtable:

template <class _Value, class _HashFcn, class _EqualKey, class _Alloc>
class hash_set
{
  // requirements:

  __STL_CLASS_REQUIRES(_Value, _Assignable);
  __STL_CLASS_UNARY_FUNCTION_CHECK(_HashFcn, size_t, _Value);
  __STL_CLASS_BINARY_FUNCTION_CHECK(_EqualKey, bool, _Value, _Value);

private:
  typedef hashtable<_Value, _Value, _HashFcn, _Identity<_Value>,
                    _EqualKey, _Alloc> _Ht;
  _Ht _M_ht; // hashtable

public:
  typedef typename _Ht::key_type key_type;
  typedef typename _Ht::value_type value_type;
  typedef typename _Ht::hasher hasher;
  typedef typename _Ht::key_equal key_equal;

  typedef typename _Ht::size_type size_type;
  typedef typename _Ht::difference_type difference_type;
  typedef typename _Ht::const_pointer pointer;
  typedef typename _Ht::const_pointer const_pointer;
  typedef typename _Ht::const_reference reference;
  typedef typename _Ht::const_reference const_reference;

  typedef typename _Ht::const_iterator iterator;
  typedef typename _Ht::const_iterator const_iterator;

  typedef typename _Ht::allocator_type allocator_type;

  hasher hash_funct() const { return _M_ht.hash_funct(); }
  key_equal key_eq() const { return _M_ht.key_eq(); }
  allocator_type get_allocator() const { return _M_ht.get_allocator(); }

public:
  // 构造函数
  hash_set()
    : _M_ht(100, hasher(), key_equal(), allocator_type()) {}
  explicit hash_set(size_type __n)
    : _M_ht(__n, hasher(), key_equal(), allocator_type()) {}
  hash_set(size_type __n, const hasher& __hf)
    : _M_ht(__n, __hf, key_equal(), allocator_type()) {}
  hash_set(size_type __n, const hasher& __hf, const key_equal& __eql,
           const allocator_type& __a = allocator_type())
    : _M_ht(__n, __hf, __eql, __a) {}

  hash_set(const value_type* __f, const value_type* __l)
    : _M_ht(100, hasher(), key_equal(), allocator_type())
    { _M_ht.insert_unique(__f, __l); }
  hash_set(const value_type* __f, const value_type* __l, size_type __n)
    : _M_ht(__n, hasher(), key_equal(), allocator_type())
    { _M_ht.insert_unique(__f, __l); }
  hash_set(const value_type* __f, const value_type* __l, size_type __n,
           const hasher& __hf)
    : _M_ht(__n, __hf, key_equal(), allocator_type())
    { _M_ht.insert_unique(__f, __l); }
  hash_set(const value_type* __f, const value_type* __l, size_type __n,
           const hasher& __hf, const key_equal& __eql,
           const allocator_type& __a = allocator_type())
    : _M_ht(__n, __hf, __eql, __a)
    { _M_ht.insert_unique(__f, __l); }

  hash_set(const_iterator __f, const_iterator __l)
    : _M_ht(100, hasher(), key_equal(), allocator_type())
    { _M_ht.insert_unique(__f, __l); }
  hash_set(const_iterator __f, const_iterator __l, size_type __n)
    : _M_ht(__n, hasher(), key_equal(), allocator_type())
    { _M_ht.insert_unique(__f, __l); }
  hash_set(const_iterator __f, const_iterator __l, size_type __n,
           const hasher& __hf)
    : _M_ht(__n, __hf, key_equal(), allocator_type())
    { _M_ht.insert_unique(__f, __l); }
  hash_set(const_iterator __f, const_iterator __l, size_type __n,
           const hasher& __hf, const key_equal& __eql,
           const allocator_type& __a = allocator_type())
    : _M_ht(__n, __hf, __eql, __a)
    { _M_ht.insert_unique(__f, __l); }
#endif /*__STL_MEMBER_TEMPLATES */

public:
  // 容量相关
  size_type size() const { return _M_ht.size(); }
  size_type max_size() const { return _M_ht.max_size(); }
  bool empty() const { return _M_ht.empty(); }
  void swap(hash_set& __hs) { _M_ht.swap(__hs._M_ht); }

  // 迭代器
  iterator begin() const { return _M_ht.begin(); }
  iterator end() const { return _M_ht.end(); }

public:
  // 插入操作
  pair<iterator, bool> insert(const value_type& __obj)
    {
      pair<typename _Ht::iterator, bool> __p = _M_ht.insert_unique(__obj);
      return pair<iterator,bool>(__p.first, __p.second);
    }
  void insert(const value_type* __f, const value_type* __l) {
    _M_ht.insert_unique(__f,__l);
  }
  void insert(const_iterator __f, const_iterator __l)
    {_M_ht.insert_unique(__f, __l); }
  pair<iterator, bool> insert_noresize(const value_type& __obj)
  {
    pair<typename _Ht::iterator, bool> __p =
      _M_ht.insert_unique_noresize(__obj);
    return pair<iterator, bool>(__p.first, __p.second);
  }

  // 查找操作
  iterator find(const key_type& __key) const { return _M_ht.find(__key); }

  // 查找某个 key 出现的次数
  size_type count(const key_type& __key) const { return _M_ht.count(__key); }

  // 查找某个 key 的迭代器范围
  pair<iterator, iterator> equal_range(const key_type& __key) const
    { return _M_ht.equal_range(__key); }

  // 删除操作
  size_type erase(const key_type& __key) {return _M_ht.erase(__key); }
  void erase(iterator __it) { _M_ht.erase(__it); }
  void erase(iterator __f, iterator __l) { _M_ht.erase(__f, __l); }
  void clear() { _M_ht.clear(); }

public:
  // 桶容量相关
  void resize(size_type __hint) { _M_ht.resize(__hint); }
  size_type bucket_count() const { return _M_ht.bucket_count(); }
  size_type max_bucket_count() const { return _M_ht.max_bucket_count(); }
  size_type elems_in_bucket(size_type __n) const
    { return _M_ht.elems_in_bucket(__n); }
};

template <class _Value, class _HashFcn, class _EqualKey, class _Alloc>
inline bool
operator==(const hash_set<_Value,_HashFcn,_EqualKey,_Alloc>& __hs1,
           const hash_set<_Value,_HashFcn,_EqualKey,_Alloc>& __hs2)
{
  return __hs1._M_ht == __hs2._M_ht;
}
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