STL源码剖析 容器 stl_set.h

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set

struct ltstr
{
  bool operator()(const char* s1, const char* s2) const
  {
    return strcmp(s1, s2) < 0;
  }
};


int main()
{
  const int N = 6;
  const char* a[N] = {"isomer", "ephemeral", "prosaic", 
                      "nugatory", "artichoke", "serif"};
  const char* b[N] = {"flat", "this", "artichoke",
                      "frigate", "prosaic", "isomer"};


  set<const char*, ltstr> A(a, a + N);
  set<const char*, ltstr> B(b, b + N);
  set<const char*, ltstr> C;


  cout << "Set A: ";
  copy(A.begin(), A.end(), ostream_iterator<const char*>(cout, " "));
  cout << endl;
  cout << "Set B: ";
  copy(B.begin(), B.end(), ostream_iterator<const char*>(cout, " "));   
  cout << endl;


  cout << "Union: ";
  set_union(A.begin(), A.end(), B.begin(), B.end(),
            ostream_iterator<const char*>(cout, " "),
            ltstr());   
  cout << endl;


  cout << "Intersection: ";
  set_intersection(A.begin(), A.end(), B.begin(), B.end(),
                   ostream_iterator<const char*>(cout, " "),
                   ltstr());    
  cout << endl;


  set_difference(A.begin(), A.end(), B.begin(), B.end(),
                 inserter(C, C.begin()),
                 ltstr());
  cout << "Set C (difference of A and B): ";
  copy(C.begin(), C.end(), ostream_iterator<const char*>(cout, " "));
  cout << endl;
}

#ifndef __SGI_STL_INTERNAL_SET_H
#define __SGI_STL_INTERNAL_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
template <class Key, class Compare = less<Key>, class Alloc = alloc>
#else
template <class Key, class Compare, class Alloc = alloc>
#endif
class set {
public:
  // typedefs:
  //key_type 和 value_type 的类型是一样的
  typedef Key key_type;
  typedef Key value_type;
  //key_compare 和 value_compare 也用到了同一个比较函数
  typedef Compare key_compare;
  typedef Compare value_compare;
private:
  //底层采用红黑树来实现 set --> 参见 Effective C++ ，这是利用了 Composition 的 is-implimented-in-terms-of 的功能
  typedef rb_tree<key_type, value_type, 
                  identity<value_type>, key_compare, Alloc> rep_type;
  rep_type t;  // red-black tree representing set
public:
  typedef typename rep_type::const_pointer pointer;
  typedef typename rep_type::const_pointer const_pointer;
  typedef typename rep_type::const_reference reference;
  typedef typename rep_type::const_reference const_reference;
  //set 的 iterator 定义为红黑树的 const_iterator，这表示 set 的迭代器无法执行写入操作。
  //这是因为 set 的元素有一定次序安排，不允许用户在任意处进行写入操作
  typedef typename rep_type::const_iterator iterator;
  typedef typename rep_type::const_iterator const_iterator;
  typedef typename rep_type::const_reverse_iterator reverse_iterator;
  typedef typename rep_type::const_reverse_iterator const_reverse_iterator;
  typedef typename rep_type::size_type size_type;
  typedef typename rep_type::difference_type difference_type;


  // allocation/deallocation
  // set 一定要使用 RB-tree 的 insert-unique() ，这样当要插入
  //已经存在的键值时，会选择忽略
  
  set() : t(Compare()) {}  // 传递 Compare() 产生的函数对象给底层的红黑树作为初始化时设定的比较函数
  explicit set(const Compare& comp) : t(comp) {}


#ifdef __STL_MEMBER_TEMPLATES
  template <class InputIterator>
  set(InputIterator first, InputIterator last)
    : t(Compare()) { t.insert_unique(first, last); }


  template <class InputIterator>
  set(InputIterator first, InputIterator last, const Compare& comp)
    : t(comp) { t.insert_unique(first, last); }
#else
  set(const value_type* first, const value_type* last) 
    : t(Compare()) { t.insert_unique(first, last); }
  set(const value_type* first, const value_type* last, const Compare& comp)
    : t(comp) { t.insert_unique(first, last); }


  set(const_iterator first, const_iterator last)
    : t(Compare()) { t.insert_unique(first, last); }
  set(const_iterator first, const_iterator last, const Compare& comp)
    : t(comp) { t.insert_unique(first, last); }
#endif /* __STL_MEMBER_TEMPLATES */


  set(const set<Key, Compare, Alloc>& x) : t(x.t) {}
  set<Key, Compare, Alloc>& operator=(const set<Key, Compare, Alloc>& x) { 
    t = x.t;     // 调用了底层红黑树的 operator= 函数
    return *this;
  }


  //以下所有的 set 操作行为，RB-tree 都已提供，所以 set 只要调用即可
  // accessors:
  
  key_compare key_comp() const { return t.key_comp(); }
  value_compare value_comp() const { return t.key_comp(); }
  iterator begin() const { return t.begin(); }
  iterator end() const { return t.end(); }
  reverse_iterator rbegin() const { return t.rbegin(); } 
  reverse_iterator rend() const { return t.rend(); }
  bool empty() const { return t.empty(); }
  size_type size() const { return t.size(); }
  size_type max_size() const { return t.max_size(); }
  void swap(set<Key, Compare, Alloc>& x) { t.swap(x.t); }


  // insert/erase
  typedef  pair<iterator, bool> pair_iterator_bool; 
  pair<iterator,bool> insert(const value_type& x) { 
    pair<typename rep_type::iterator, bool> p = t.insert_unique(x); 
    return pair<iterator, bool>(p.first, p.second);
  }
  iterator insert(iterator position, const value_type& x) {
    typedef typename rep_type::iterator rep_iterator;
    return t.insert_unique((rep_iterator&)position, x);
  }
#ifdef __STL_MEMBER_TEMPLATES
  template <class InputIterator>
  void insert(InputIterator first, InputIterator last) {
    t.insert_unique(first, last);
  }
#else
  void insert(const_iterator first, const_iterator last) {
    t.insert_unique(first, last);
  }
  void insert(const value_type* first, const value_type* last) {
    t.insert_unique(first, last);
  }
#endif /* __STL_MEMBER_TEMPLATES */
  void erase(iterator position) { 
    typedef typename rep_type::iterator rep_iterator;
    t.erase((rep_iterator&)position); 
  }
  size_type erase(const key_type& x) { 
    return t.erase(x); 
  }
  void erase(iterator first, iterator last) { 
    typedef typename rep_type::iterator rep_iterator;
    t.erase((rep_iterator&)first, (rep_iterator&)last); 
  }
  void clear() { t.clear(); }


  // set operations:


  iterator find(const key_type& x) const { return t.find(x); }
  size_type count(const key_type& x) const { return t.count(x); }
  iterator lower_bound(const key_type& x) const {
    return t.lower_bound(x);
  }
  iterator upper_bound(const key_type& x) const {
    return t.upper_bound(x); 
  }
  pair<iterator,iterator> equal_range(const key_type& x) const {
    return t.equal_range(x);
  }
  friend bool operator== __STL_NULL_TMPL_ARGS (const set&, const set&);
  friend bool operator< __STL_NULL_TMPL_ARGS (const set&, const set&);
};


template <class Key, class Compare, class Alloc>
inline bool operator==(const set<Key, Compare, Alloc>& x, 
                       const set<Key, Compare, Alloc>& y) {
  return x.t == y.t;
}


template <class Key, class Compare, class Alloc>
inline bool operator<(const set<Key, Compare, Alloc>& x, 
                      const set<Key, Compare, Alloc>& y) {
  return x.t < y.t;
}


#ifdef __STL_FUNCTION_TMPL_PARTIAL_ORDER


template <class Key, class Compare, class Alloc>
inline void swap(set<Key, Compare, Alloc>& x, 
                 set<Key, Compare, Alloc>& y) {
  x.swap(y);
}


#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_SET_H */


// Local Variables:
// mode:C++
// End:

STL源码剖析 容器 stl_set.h,布布扣,bubuko.com

STL源码剖析 容器 stl_set.h

标签：style   blog   http   color   使用   os   

原文地址：http://blog.csdn.net/zhengsenlie/article/details/38045005