STL关联式容器-hashset
目录
STL 只规范复杂度与接口,并不规范实现方法,但是STL set多半以RB-tree为底层实现机制,SGI则是STL标准规定之外另又提供了一个所谓的hash_set, 以hashtable为底层机制。
RB-tree有自动排序功能而hashtable没有。
hash_multiset 与 hash_set 使用起来相同,只是 hash_multiset 中允许键值重复
在源码中,hash_multiset 调用的是 insert_equal (),而 hash_set 调用的是 insert_unique ()
1. 数据结构
#ifndef __STL_LIMITED_DEFAULT_TEMPLATES
template <class Value, class HashFcn = hash<Value>,
class EqualKey = equal_to<Value>,
class Alloc = alloc>
#else
template <class Value, class HashFcn, class EqualKey, class Alloc = alloc>
#endif
class hash_set
{
private:
typedef hashtable<Value, Value, HashFcn, identity<Value>,
EqualKey, Alloc> ht;
ht rep;
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;
hasher hash_funct() const { return rep.hash_funct(); }
key_equal key_eq() const { return rep.key_eq(); }
public:
hash_set() : rep(100, hasher(), key_equal()) {}
explicit hash_set(size_type n) : rep(n, hasher(), key_equal()) {}
hash_set(size_type n, const hasher& hf) : rep(n, hf, key_equal()) {}
hash_set(size_type n, const hasher& hf, const key_equal& eql)
: rep(n, hf, eql) {}
#ifdef __STL_MEMBER_TEMPLATES
template <class InputIterator>
hash_set(InputIterator f, InputIterator l)
: rep(100, hasher(), key_equal()) { rep.insert_unique(f, l); }
template <class InputIterator>
hash_set(InputIterator f, InputIterator l, size_type n)
: rep(n, hasher(), key_equal()) { rep.insert_unique(f, l); }
template <class InputIterator>
hash_set(InputIterator f, InputIterator l, size_type n,
const hasher& hf)
: rep(n, hf, key_equal()) { rep.insert_unique(f, l); }
template <class InputIterator>
hash_set(InputIterator f, InputIterator l, size_type n,
const hasher& hf, const key_equal& eql)
: rep(n, hf, eql) { rep.insert_unique(f, l); }
#else
hash_set(const value_type* f, const value_type* l)
: rep(100, hasher(), key_equal()) { rep.insert_unique(f, l); }
hash_set(const value_type* f, const value_type* l, size_type n)
: rep(n, hasher(), key_equal()) { rep.insert_unique(f, l); }
hash_set(const value_type* f, const value_type* l, size_type n,
const hasher& hf)
: rep(n, hf, key_equal()) { rep.insert_unique(f, l); }
hash_set(const value_type* f, const value_type* l, size_type n,
const hasher& hf, const key_equal& eql)
: rep(n, hf, eql) { rep.insert_unique(f, l); }
hash_set(const_iterator f, const_iterator l)
: rep(100, hasher(), key_equal()) { rep.insert_unique(f, l); }
hash_set(const_iterator f, const_iterator l, size_type n)
: rep(n, hasher(), key_equal()) { rep.insert_unique(f, l); }
hash_set(const_iterator f, const_iterator l, size_type n,
const hasher& hf)
: rep(n, hf, key_equal()) { rep.insert_unique(f, l); }
hash_set(const_iterator f, const_iterator l, size_type n,
const hasher& hf, const key_equal& eql)
: rep(n, hf, eql) { rep.insert_unique(f, l); }
#endif /*__STL_MEMBER_TEMPLATES */
public:
size_type size() const { return rep.size(); }
size_type max_size() const { return rep.max_size(); }
bool empty() const { return rep.empty(); }
void swap(hash_set& hs) { rep.swap(hs.rep); }
friend bool operator== __STL_NULL_TMPL_ARGS (const hash_set&,
const hash_set&);
iterator begin() const { return rep.begin(); }
iterator end() const { return rep.end(); }
public:
pair<iterator, bool> insert(const value_type& obj)
{
pair<typename ht::iterator, bool> p = rep.insert_unique(obj);
return pair<iterator, bool>(p.first, p.second);
}
#ifdef __STL_MEMBER_TEMPLATES
template <class InputIterator>
void insert(InputIterator f, InputIterator l) { rep.insert_unique(f,l); }
#else
void insert(const value_type* f, const value_type* l) {
rep.insert_unique(f,l);
}
void insert(const_iterator f, const_iterator l) {rep.insert_unique(f, l); }
#endif /*__STL_MEMBER_TEMPLATES */
pair<iterator, bool> insert_noresize(const value_type& obj)
{
pair<typename ht::iterator, bool> p = rep.insert_unique_noresize(obj);
return pair<iterator, bool>(p.first, p.second);
}
iterator find(const key_type& key) const { return rep.find(key); }
size_type count(const key_type& key) const { return rep.count(key); }
pair<iterator, iterator> equal_range(const key_type& key) const
{ return rep.equal_range(key); }
size_type erase(const key_type& key) {return rep.erase(key); }
void erase(iterator it) { rep.erase(it); }
void erase(iterator f, iterator l) { rep.erase(f, l); }
void clear() { rep.clear(); }
public:
void resize(size_type hint) { rep.resize(hint); }
size_type bucket_count() const { return rep.bucket_count(); }
size_type max_bucket_count() const { return rep.max_bucket_count(); }
size_type elems_in_bucket(size_type n) const
{ return rep.elems_in_bucket(n); }
};