《STL源码剖析》---stl_hash_set.h阅读笔记
STL只规定接口和复杂度，对于具体实现不作要求。set大多以红黑树实现，但STL在标准规格之外提供了一个所谓的hash_set，以hash table实现。hash_set的接口，hash_table都提供了，所以几乎所有的hash_set操作都是直接调用hash_table的函数而已。
除了hash_set，还有hash_multiset，它们两个的关系就像set和multiset的关系，一个不允许键值重复，另外一个允许键值重复。其他实现一样。
G++ 2.91.57，cygnus\cygwin-b20\include\g++\stl_hash_set.h 完整列表
/*
* Copyright (c) 1996
* Silicon Graphics Computer Systems, Inc.
*
* Permission to use, copy, modify, distribute and sell this software
* and its documentation for any purpose is hereby granted without fee,
* provided that the above copyright notice appear in all copies and
* that both that copyright notice and this permission notice appear
* in supporting documentation. Silicon Graphics makes no
* representations about the suitability of this software for any
* purpose. It is provided "as is" without express or implied warranty.
*
*
* Copyright (c) 1994
* Hewlett-Packard Company
*
* Permission to use, copy, modify, distribute and sell this software
* and its documentation for any purpose is hereby granted without fee,
* provided that the above copyright notice appear in all copies and
* that both that copyright notice and this permission notice appear
* in supporting documentation. Hewlett-Packard Company makes no
* representations about the suitability of this software for any
* purpose. It is provided "as is" without express or implied warranty.
*
*/
/* NOTE: This is an internal header file, included by other STL headers.
* You should not attempt to use it directly.
*/
#ifndef __SGI_STL_INTERNAL_HASH_SET_H
#define __SGI_STL_INTERNAL_HASH_SET_H
__STL_BEGIN_NAMESPACE
#if defined(__sgi) && !defined(__GNUC__) && (_MIPS_SIM != _MIPS_SIM_ABI32)
#pragma set woff 1174
#endif
#ifndef __STL_LIMITED_DEFAULT_TEMPLATES
// hash<>是个 function object，定义于 <stl_hash_fun.h>中
//例：hash<int>::operator()(intx)const{return x;}
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:
// 以下使用的 identity<> 定义于 <stl_function.h> 中。
typedef hashtable<Value, Value, HashFcn, identity<Value>,
EqualKey, Alloc> ht;
ht rep; // 底层机制以 hash table 完成
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:
//预设使用大小为100的vector buckets。将会自动调整为比100大的质数
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) {}
// 插入全部调用 insert_unique()，不允许键值重复
#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:
// 所有操作几乎都是调用 hash table的函数。
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); }
};
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.rep == hs2.rep;
}
#ifdef __STL_FUNCTION_TMPL_PARTIAL_ORDER
template <class Val, class HashFcn, class EqualKey, class Alloc>
inline void swap(hash_set<Val, HashFcn, EqualKey, Alloc>& hs1,
hash_set<Val, HashFcn, EqualKey, Alloc>& hs2) {
hs1.swap(hs2);
}
#endif /* __STL_FUNCTION_TMPL_PARTIAL_ORDER */
//hash_multiset允许键值重复，其他与hash_set一样
#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_multiset
{
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_multiset() : rep(100, hasher(), key_equal()) {}
explicit hash_multiset(size_type n) : rep(n, hasher(), key_equal()) {}
hash_multiset(size_type n, const hasher& hf) : rep(n, hf, key_equal()) {}
hash_multiset(size_type n, const hasher& hf, const key_equal& eql)
: rep(n, hf, eql) {}
// 以下，插入全部使用 insert_equal()，允许键值重复
#ifdef __STL_MEMBER_TEMPLATES
template <class InputIterator>
hash_multiset(InputIterator f, InputIterator l)
: rep(100, hasher(), key_equal()) { rep.insert_equal(f, l); }
template <class InputIterator>
hash_multiset(InputIterator f, InputIterator l, size_type n)
: rep(n, hasher(), key_equal()) { rep.insert_equal(f, l); }
template <class InputIterator>
hash_multiset(InputIterator f, InputIterator l, size_type n,
const hasher& hf)
: rep(n, hf, key_equal()) { rep.insert_equal(f, l); }
template <class InputIterator>
hash_multiset(InputIterator f, InputIterator l, size_type n,
const hasher& hf, const key_equal& eql)
: rep(n, hf, eql) { rep.insert_equal(f, l); }
#else
hash_multiset(const value_type* f, const value_type* l)
: rep(100, hasher(), key_equal()) { rep.insert_equal(f, l); }
hash_multiset(const value_type* f, const value_type* l, size_type n)
: rep(n, hasher(), key_equal()) { rep.insert_equal(f, l); }
hash_multiset(const value_type* f, const value_type* l, size_type n,
const hasher& hf)
: rep(n, hf, key_equal()) { rep.insert_equal(f, l); }
hash_multiset(const value_type* f, const value_type* l, size_type n,
const hasher& hf, const key_equal& eql)
: rep(n, hf, eql) { rep.insert_equal(f, l); }
hash_multiset(const_iterator f, const_iterator l)
: rep(100, hasher(), key_equal()) { rep.insert_equal(f, l); }
hash_multiset(const_iterator f, const_iterator l, size_type n)
: rep(n, hasher(), key_equal()) { rep.insert_equal(f, l); }
hash_multiset(const_iterator f, const_iterator l, size_type n,
const hasher& hf)
: rep(n, hf, key_equal()) { rep.insert_equal(f, l); }
hash_multiset(const_iterator f, const_iterator l, size_type n,
const hasher& hf, const key_equal& eql)
: rep(n, hf, eql) { rep.insert_equal(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_multiset& hs) { rep.swap(hs.rep); }
friend bool operator== __STL_NULL_TMPL_ARGS (const hash_multiset&,
const hash_multiset&);
iterator begin() const { return rep.begin(); }
iterator end() const { return rep.end(); }
public:
iterator insert(const value_type& obj) { return rep.insert_equal(obj); }
#ifdef __STL_MEMBER_TEMPLATES
template <class InputIterator>
void insert(InputIterator f, InputIterator l) { rep.insert_equal(f,l); }
#else
void insert(const value_type* f, const value_type* l) {
rep.insert_equal(f,l);
}
void insert(const_iterator f, const_iterator l) { rep.insert_equal(f, l); }
#endif /*__STL_MEMBER_TEMPLATES */
iterator insert_noresize(const value_type& obj)
{ return rep.insert_equal_noresize(obj); }
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); }
};
template <class Val, class HashFcn, class EqualKey, class Alloc>
inline bool operator==(const hash_multiset<Val, HashFcn, EqualKey, Alloc>& hs1,
const hash_multiset<Val, HashFcn, EqualKey, Alloc>& hs2)
{
return hs1.rep == hs2.rep;
}
#ifdef __STL_FUNCTION_TMPL_PARTIAL_ORDER
template <class Val, class HashFcn, class EqualKey, class Alloc>
inline void swap(hash_multiset<Val, HashFcn, EqualKey, Alloc>& hs1,
hash_multiset<Val, HashFcn, EqualKey, Alloc>& hs2)
{
hs1.swap(hs2);
}
#endif /* __STL_FUNCTION_TMPL_PARTIAL_ORDER */
#if defined(__sgi) && !defined(__GNUC__) && (_MIPS_SIM != _MIPS_SIM_ABI32)
#pragma reset woff 1174
#endif
__STL_END_NAMESPACE
#endif /* __SGI_STL_INTERNAL_HASH_SET_H */
// Local Variables:
// mode:C++
// End: