《STL源码剖析》---stl_slist.h阅读笔记

标签：c++   stl   源码   slist   单向链表   

slist(single linked list)是单向链表。它不是STL的标准，它与标准list的主要不同在于迭代器。slist的迭代器是Forward iterator，而list的迭代器是Bidirectional iterator，所以slist有着更多的限制。从另一方面看，slist消耗空间更小，一些操作更快。由于slist是单向的，所以在查找迭代器的前一个结点时比较麻烦，要从头开始找。也就是说slist在头结点插入和删除，在其他位置操作代价都比较大。

G++ 2.91.57，cygnus\cygwin-b20\include\g++\stl_slist.h 完整列表
/*
 * Copyright (c) 1997
 * 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.
 *
 */

/* NOTE: This is an internal header file, included by other STL headers.
 *   You should not attempt to use it directly.
 */

#ifndef __SGI_STL_INTERNAL_SLIST_H
#define __SGI_STL_INTERNAL_SLIST_H


__STL_BEGIN_NAMESPACE 

#if defined(__sgi) && !defined(__GNUC__) && (_MIPS_SIM != _MIPS_SIM_ABI32)
#pragma set woff 1174
#endif

// 单向结点的结构
struct __slist_node_base
{
  __slist_node_base* next;
};

//全局函数：在prev_node后插入new_node
inline __slist_node_base* __slist_make_link(__slist_node_base* prev_node,
                                            __slist_node_base* new_node)
{

  new_node->next = prev_node->next;  
  prev_node->next = new_node;		
  return new_node;
}


//全局函数，找出某一个结点的前面的结点。由于是单向链表，需要从头往后找。
//找不到的话返回最后一个节点的next，即NULL
inline __slist_node_base* __slist_previous(__slist_node_base* head,
                                           const __slist_node_base* node)
{
  while (head && head->next != node)	// 在單向串列中，只能採用循序搜尋法
    head = head->next;
  return head;
}


inline const __slist_node_base* __slist_previous(const __slist_node_base* head,
                                                 const __slist_node_base* node)
{
  while (head && head->next != node)
    head = head->next;
  return head;
}

/*
把(before_first before_last]插入到pos后面，不包括before_first，包括before_last
(before_first before_last]在原有链表上移除
*/
inline void __slist_splice_after(__slist_node_base* pos,
                                 __slist_node_base* before_first,
                                 __slist_node_base* before_last)
{
	//pos==before_first的话操作无意义（操作前后不变化）
	//pos==before_last的话会形成环。难道不能形成环？
  if (pos != before_first && pos != before_last) {
    __slist_node_base* first = before_first->next;
    __slist_node_base* after = pos->next;
	
	//(before_first before_last]在原有链表上移除
    before_first->next = before_last->next;
	//插入到pos后面
    pos->next = first;
    before_last->next = after;
  }
}


//单向链表反转，反转node后面的结点（包括node）反转后node为尾结点
inline __slist_node_base* __slist_reverse(__slist_node_base* node)
{
  __slist_node_base* result = node;
  node = node->next;
  result->next = 0;//node成为尾结点了
  /*非递归反转单向链表。维护两个指针node和result，node在前，result在后
    node->next = result;使两个结点反转。依次移动指针直到末尾。
  */
  while(node) {
    __slist_node_base* next = node->next;
    node->next = result;//反转
	//下面两步完成指针后移
    result = node;
    node = next;
  }
  return result;
}

// 单向链表结点的结构。继承了__slist_node_base，其中有next指针
//next指针是__slist_node_base*类型，基类指针可以指向派生类对象
template <class T>
struct __slist_node : public __slist_node_base
{
  T data;
};

//单向链表的迭代器的基类
struct __slist_iterator_base
{
  typedef size_t size_type;
  typedef ptrdiff_t difference_type;
  typedef forward_iterator_tag iterator_category;	// 注意，是单向的

  __slist_node_base* node;	// 指向结点的指针
	
	//构造函数，用指针类初始化
  __slist_iterator_base(__slist_node_base* x) : node(x) {}
	//迭代器前进一个位置
  void incr() { node = node->next; }
	//判断迭代器是否相等
  bool operator==(const __slist_iterator_base& x) const {
    return node == x.node;
  }
  bool operator!=(const __slist_iterator_base& x) const {
    return node != x.node;
  }
};

//单向链表的迭代器的派生类。派生类没有再定义数据成员，只是实现了几个
//成员函数。
template <class T, class Ref, class Ptr>
struct __slist_iterator : public __slist_iterator_base
{
  typedef __slist_iterator<T, T&, T*>             iterator;
  typedef __slist_iterator<T, const T&, const T*> const_iterator;
  typedef __slist_iterator<T, Ref, Ptr>           self;

  typedef T value_type;
  typedef Ptr pointer;
  typedef Ref reference;
  typedef __slist_node<T> list_node;

	
	//以下几个构造函数都是通过调用基类的构造函数来初始化的
	
	//用指针来初始化，指针类型有转换
  __slist_iterator(list_node* x) : __slist_iterator_base(x) {}
  // 默认构造函数
  __slist_iterator() : __slist_iterator_base(0) {}
  //复制构造函数
  __slist_iterator(const iterator& x) : __slist_iterator_base(x.node) {}

  reference operator*() const { return ((list_node*) node)->data; }
#ifndef __SGI_STL_NO_ARROW_OPERATOR
  pointer operator->() const { return &(operator*()); }
#endif /* __SGI_STL_NO_ARROW_OPERATOR */
	//前进，没有后退
  self& operator++()
  {
    incr();	
    return *this;
  }
  self operator++(int)
  {
    self tmp = *this;
    incr();	
    return tmp;
  }


};

#ifndef __STL_CLASS_PARTIAL_SPECIALIZATION

inline ptrdiff_t*
distance_type(const __slist_iterator_base&)
{
  return 0;
}

inline forward_iterator_tag
iterator_category(const __slist_iterator_base&)
{
  return forward_iterator_tag();
}

template <class T, class Ref, class Ptr> 
inline T* 
value_type(const __slist_iterator<T, Ref, Ptr>&) {
  return 0;
}

#endif /* __STL_CLASS_PARTIAL_SPECIALIZATION */

//全局函数，计算node结点到尾结点的距离，如果node是头结点，就是计算slist长度
inline size_t __slist_size(__slist_node_base* node)
{
  size_t result = 0;
  for ( ; node != 0; node = node->next)
    ++result;		// 累計
  return result;
}

// 单向链表，默认使用alloc空间配置器
template <class T, class Alloc = alloc>
class slist
{
public:
  typedef T value_type;
  typedef value_type* pointer;
  typedef const value_type* const_pointer;
  typedef value_type& reference;
  typedef const value_type& const_reference;
  typedef size_t size_type;
  typedef ptrdiff_t difference_type;

  typedef __slist_iterator<T, T&, T*>             iterator;
  typedef __slist_iterator<T, const T&, const T*> const_iterator;

private:
  typedef __slist_node<T> list_node;
  typedef __slist_node_base list_node_base;
  typedef __slist_iterator_base iterator_base;
  typedef simple_alloc<list_node, Alloc> list_node_allocator;

  //创建一个结点，用x初始化该结点
  static list_node* create_node(const value_type& x) {
    list_node* node = list_node_allocator::allocate();	// 配置空間
    __STL_TRY {
      construct(&node->data, x);		// 在空间上构建元素
      node->next = 0;
    }
	//commit or rollback
    __STL_UNWIND(list_node_allocator::deallocate(node));
    return node;
  }
  
  static void destroy_node(list_node* node) {
    destroy(&node->data);		// 析构
    list_node_allocator::deallocate(node);	// 释放空间
  }
//用n个值为x的结点初始化链表
  void fill_initialize(size_type n, const value_type& x) {
    head.next = 0;//头结点归零
    __STL_TRY {
      _insert_after_fill(&head, n, x);
    }
    __STL_UNWIND(clear());
  }    
//用一段元素初始化链表
#ifdef __STL_MEMBER_TEMPLATES
  template <class InputIterator>
  void range_initialize(InputIterator first, InputIterator last) {
    head.next = 0;
    __STL_TRY {
      _insert_after_range(&head, first, last);
    }
    __STL_UNWIND(clear());
  }
#else /* __STL_MEMBER_TEMPLATES */
  void range_initialize(const value_type* first, const value_type* last) {
    head.next = 0;
    __STL_TRY {
      _insert_after_range(&head, first, last);
    }
    __STL_UNWIND(clear());
  }
  void range_initialize(const_iterator first, const_iterator last) {
    head.next = 0;
    __STL_TRY {
      _insert_after_range(&head, first, last);
    }
    __STL_UNWIND(clear());
  }
#endif /* __STL_MEMBER_TEMPLATES */

private:
  list_node_base head;	 // 头结点，注意：它不是指针 

public:
  slist() { head.next = 0; } 
	//构造函数
  slist(size_type n, const value_type& x) { fill_initialize(n, x); }
  slist(int n, const value_type& x) { fill_initialize(n, x); }
  slist(long n, const value_type& x) { fill_initialize(n, x); }
  //value_type()说明要支持默认构造函数
  explicit slist(size_type n) { fill_initialize(n, value_type()); }

#ifdef __STL_MEMBER_TEMPLATES
  template <class InputIterator>
  slist(InputIterator first, InputIterator last) {
    range_initialize(first, last);
  }

#else /* __STL_MEMBER_TEMPLATES */
  slist(const_iterator first, const_iterator last) {
    range_initialize(first, last);
  }
  slist(const value_type* first, const value_type* last) {
    range_initialize(first, last);
  }
#endif /* __STL_MEMBER_TEMPLATES */
//用一个链表来初始化本链表
  slist(const slist& L) { range_initialize(L.begin(), L.end()); }
//用链表L给本链表赋值
  slist& operator= (const slist& L);
//析构
  ~slist() { clear(); }

public:
	//begin()是返回指向第一个结点的迭代器，head对外不可见
  iterator begin() { return iterator((list_node*)head.next); }
  const_iterator begin() const { return const_iterator((list_node*)head.next);}
	//end返回空迭代器，即最后一个结点的下一个位置
  iterator end() { return iterator(0); }
  const_iterator end() const { return const_iterator(0); }
//slist大小
  size_type size() const { return __slist_size(head.next); }
  //无意义吧？
  size_type max_size() const { return size_type(-1); }

  bool empty() const { return head.next == 0; }

  //两个slist互换，只是交换head的next指针而已
  void swap(slist& L)
  {
    list_node_base* tmp = head.next;
    head.next = L.head.next;
    L.head.next = tmp;
  }

public:
//友元函数
  friend bool operator== __STL_NULL_TMPL_ARGS(const slist<T, Alloc>& L1,
                                              const slist<T, Alloc>& L2);

public:

  // 取头部元素
  reference front() { return ((list_node*) head.next)->data; }
  const_reference front() const { return ((list_node*) head.next)->data; }

  //插入元素，注意：这是在头部插入元素
  void push_front(const value_type& x)   {
    __slist_make_link(&head, create_node(x));
  }

  // 注意，沒有 push_back()

  //从头部取走元素（删除）。
  void pop_front() {
    list_node* node = (list_node*) head.next;
	//没有判断node是否为空指针
    head.next = node->next;
    destroy_node(node);
  }
//找pos前面的迭代器
  iterator previous(const_iterator pos) {
    return iterator((list_node*) __slist_previous(&head, pos.node));
  }
  const_iterator previous(const_iterator pos) const {
    return const_iterator((list_node*) __slist_previous(&head, pos.node));
  }

  //在pos后面插入元素（一个或多个）
private:
  list_node* _insert_after(list_node_base* pos, const value_type& x) {
    return (list_node*) (__slist_make_link(pos, create_node(x)));
  }

  void _insert_after_fill(list_node_base* pos,
                          size_type n, const value_type& x) {
    for (size_type i = 0; i < n; ++i)
      pos = __slist_make_link(pos, create_node(x));
  }

  //在pos后面插入一段元素
#ifdef __STL_MEMBER_TEMPLATES
  template <class InIter>
  void _insert_after_range(list_node_base* pos, InIter first, InIter last) {
    while (first != last) {
      pos = __slist_make_link(pos, create_node(*first));
      ++first;
    }
  }
#else /* __STL_MEMBER_TEMPLATES */
  void _insert_after_range(list_node_base* pos,
                           const_iterator first, const_iterator last) {
    while (first != last) {
      pos = __slist_make_link(pos, create_node(*first));
      ++first;
    }
  }
  void _insert_after_range(list_node_base* pos,
                           const value_type* first, const value_type* last) {
    while (first != last) {
      pos = __slist_make_link(pos, create_node(*first));
      ++first;
    }
  }
#endif /* __STL_MEMBER_TEMPLATES */

  //删除pos的下一个元素，并返回新的下一个元素
  list_node_base* erase_after(list_node_base* pos) {
    list_node* next = (list_node*) (pos->next);	// 下一个元素
    list_node_base* next_next = next->next;		// 下下个元素
    pos->next = next_next;	// 串接
    destroy_node(next);	// 刪除
    return next_next;		// 返回
  }
   //删除(before_first last_node)，不包括这两个结点
  list_node_base* erase_after(list_node_base* before_first,
                              list_node_base* last_node) {
    list_node* cur = (list_node*) (before_first->next);
    while (cur != last_node) {
      list_node* tmp = cur;
      cur = (list_node*) cur->next;
      destroy_node(tmp);
    }
    before_first->next = last_node;
    return last_node;
  }


public:
//在pos后面插入一个或者多个或者一段元素
  iterator insert_after(iterator pos, const value_type& x) {
    return iterator(_insert_after(pos.node, x));
  }

  iterator insert_after(iterator pos) {
    return insert_after(pos, value_type());
  }

  void insert_after(iterator pos, size_type n, const value_type& x) {
    _insert_after_fill(pos.node, n, x);
  }
  void insert_after(iterator pos, int n, const value_type& x) {
    _insert_after_fill(pos.node, (size_type) n, x);
  }
  void insert_after(iterator pos, long n, const value_type& x) {
    _insert_after_fill(pos.node, (size_type) n, x);
  }

#ifdef __STL_MEMBER_TEMPLATES
  template <class InIter>
  void insert_after(iterator pos, InIter first, InIter last) {
    _insert_after_range(pos.node, first, last);
  }
#else /* __STL_MEMBER_TEMPLATES */
  void insert_after(iterator pos, const_iterator first, const_iterator last) {
    _insert_after_range(pos.node, first, last);
  }
  void insert_after(iterator pos,
                    const value_type* first, const value_type* last) {
    _insert_after_range(pos.node, first, last);
  }
#endif /* __STL_MEMBER_TEMPLATES */
//在pos前面插入元素。在插入之前首先要找到pos前面的结点
  iterator insert(iterator pos, const value_type& x) {
    return iterator(_insert_after(__slist_previous(&head, pos.node), x));
  }

  iterator insert(iterator pos) {
    return iterator(_insert_after(__slist_previous(&head, pos.node),
                                  value_type()));
  }

  void insert(iterator pos, size_type n, const value_type& x) {
    _insert_after_fill(__slist_previous(&head, pos.node), n, x);
  } 
  void insert(iterator pos, int n, const value_type& x) {
    _insert_after_fill(__slist_previous(&head, pos.node), (size_type) n, x);
  } 
  void insert(iterator pos, long n, const value_type& x) {
    _insert_after_fill(__slist_previous(&head, pos.node), (size_type) n, x);
  } 
    
#ifdef __STL_MEMBER_TEMPLATES
  template <class InIter>
  void insert(iterator pos, InIter first, InIter last) {
    _insert_after_range(__slist_previous(&head, pos.node), first, last);
  }
#else /* __STL_MEMBER_TEMPLATES */
  void insert(iterator pos, const_iterator first, const_iterator last) {
    _insert_after_range(__slist_previous(&head, pos.node), first, last);
  }
  void insert(iterator pos, const value_type* first, const value_type* last) {
    _insert_after_range(__slist_previous(&head, pos.node), first, last);
  }
#endif /* __STL_MEMBER_TEMPLATES */


public:
//擦除pos后面的元素（一个或多个）
  iterator erase_after(iterator pos) {
    return iterator((list_node*)erase_after(pos.node));
  }
  iterator erase_after(iterator before_first, iterator last) {
    return iterator((list_node*)erase_after(before_first.node, last.node));
  }

  iterator erase(iterator pos) {
    return (list_node*) erase_after(__slist_previous(&head, pos.node));
  }
  //擦出一段元素
  iterator erase(iterator first, iterator last) {
    return (list_node*) erase_after(__slist_previous(&head, first.node),
                                    last.node);
  }
//设置slist的大小，初始化为x或默认值T()（要支持默认构造函数）
  void resize(size_type new_size, const T& x);
  void resize(size_type new_size) { resize(new_size, T()); }
  void clear() { erase_after(&head, 0); }

public:

  //把[before_first + 1, before_last + 1)添加到pos后面。时间复杂度为O(n)
  void splice_after(iterator pos, 
                    iterator before_first, iterator before_last)
  {
    if (before_first != before_last) 
      __slist_splice_after(pos.node, before_first.node, before_last.node);
  }

  
  //在pos后面插入prev
  void splice_after(iterator pos, iterator prev)
  {
    __slist_splice_after(pos.node, prev.node, prev.node->next);
  }


  // Linear in distance(begin(), pos), and linear in L.size().
  //在pos前面插入slist L
  void splice(iterator pos, slist& L) {
    if (L.head.next)
      __slist_splice_after(__slist_previous(&head, pos.node),
                           &L.head,
                           __slist_previous(&L.head, 0));
  }

  // Linear in distance(begin(), pos), and in distance(L.begin(), i).
  //在pos前面插入slist L的一段元素(L.begin(), i)
  void splice(iterator pos, slist& L, iterator i) {
    __slist_splice_after(__slist_previous(&head, pos.node),
                         __slist_previous(&L.head, i.node),
                         i.node);
  }

  // Linear in distance(begin(), pos), in distance(L.begin(), first),
  // and in distance(first, last).
  //在pos前面插入slist L的一段元素(first, last)
  void splice(iterator pos, slist& L, iterator first, iterator last)
  {
    if (first != last)
      __slist_splice_after(__slist_previous(&head, pos.node),
                           __slist_previous(&L.head, first.node),
                           __slist_previous(first.node, last.node));
  }

public:
	//反转
  void reverse() { if (head.next) head.next = __slist_reverse(head.next); }
//移除值为val的元素
  void remove(const T& val); 
  void unique(); 
  void merge(slist& L);
  void sort();     

#ifdef __STL_MEMBER_TEMPLATES
  template <class Predicate> void remove_if(Predicate pred);
  template <class BinaryPredicate> void unique(BinaryPredicate pred); 
  template <class StrictWeakOrdering> void merge(slist&, StrictWeakOrdering); 
  template <class StrictWeakOrdering> void sort(StrictWeakOrdering comp); 
#endif /* __STL_MEMBER_TEMPLATES */
};

template <class T, class Alloc>
slist<T, Alloc>& slist<T,Alloc>::operator=(const slist<T, Alloc>& L)
{
  if (&L != this) {//防止自身赋值
    list_node_base* p1 = &head;
    list_node* n1 = (list_node*) head.next;
    const list_node* n2 = (const list_node*) L.head.next;
    while (n1 && n2) {//前面的公共长度部分用值赋值
      n1->data = n2->data;
      p1 = n1;
      n1 = (list_node*) n1->next;
      n2 = (const list_node*) n2->next;
    }
    if (n2 == 0)//this链表比L长，擦出this多出的部分
      erase_after(p1, 0);
    else//this链表比L短，在后面插入L多出的部分
      _insert_after_range(p1,
                          const_iterator((list_node*)n2), const_iterator(0));
  }
  return *this;
} 
//判断两个链表是否相等。相等是指长度相同，且对应位置结点的值相等
template <class T, class Alloc>
bool operator==(const slist<T, Alloc>& L1, const slist<T, Alloc>& L2)
{
  typedef typename slist<T,Alloc>::list_node list_node;
  list_node* n1 = (list_node*) L1.head.next;
  list_node* n2 = (list_node*) L2.head.next;
  while (n1 && n2 && n1->data == n2->data) {
    n1 = (list_node*) n1->next;
    n2 = (list_node*) n2->next;
  }
  return n1 == 0 && n2 == 0;
}
//比较两个slist。lexicographical_compare为STL算法
template <class T, class Alloc>
inline bool operator<(const slist<T, Alloc>& L1, const slist<T, Alloc>& L2)
{
  return lexicographical_compare(L1.begin(), L1.end(), L2.begin(), L2.end());
}

#ifdef __STL_FUNCTION_TMPL_PARTIAL_ORDER
//交换两个slist
template <class T, class Alloc>
inline void swap(slist<T, Alloc>& x, slist<T, Alloc>& y) {
  x.swap(y);
}

#endif /* __STL_FUNCTION_TMPL_PARTIAL_ORDER */

//重新定义slist的大小。
template <class T, class Alloc>
void slist<T, Alloc>::resize(size_type len, const T& x)
{
  list_node_base* cur = &head;
  while (cur->next != 0 && len > 0) {
    --len;
    cur = cur->next;
  }
  if (cur->next) //如果slist长度大于len，擦除多余的
    erase_after(cur, 0);
  else//如果slist长度小于len，在后面插入x
    _insert_after_fill(cur, len, x);
}
//移除值为val的结点
template <class T, class Alloc>
void slist<T,Alloc>::remove(const T& val)
{
  list_node_base* cur = &head;
  //由于是单向的，所以移除时，移除的是next->next
  while (cur && cur->next) {
    if (((list_node*) cur->next)->data == val)
      erase_after(cur);
    else
      cur = cur->next;
  }
}
//相邻结点值相同的话，移除后面那个
template <class T, class Alloc> 
void slist<T,Alloc>::unique()
{
  list_node_base* cur = head.next;
  if (cur) {
    while (cur->next) {
      if (((list_node*)cur)->data == ((list_node*)(cur->next))->data)
        erase_after(cur);
      else
        cur = cur->next;
    }
  }
}

//合并两个slist，此时两个slist已经升序排列好了
template <class T, class Alloc>
void slist<T,Alloc>::merge(slist<T,Alloc>& L)
{
  list_node_base* n1 = &head;
  while (n1->next && L.head.next) {
    if (((list_node*) L.head.next)->data < ((list_node*) n1->next)->data) 
      __slist_splice_after(n1, &L.head, L.head.next);
    n1 = n1->next;
  }
  if (L.head.next) {
    n1->next = L.head.next;
    L.head.next = 0;
  }
}
//按照升序排序。不支持STL sort排序，迭代器不符合要求
//这里是快排，可以参考这里：http://blog.csdn.net/zhizichina/article/details/7538974
template <class T, class Alloc>
void slist<T,Alloc>::sort()
{
  if (head.next && head.next->next) {
    slist carry;
    slist counter[64];
    int fill = 0;
    while (!empty()) {
      __slist_splice_after(&carry.head, &head, head.next);
      int i = 0;
      while (i < fill && !counter[i].empty()) {
        counter[i].merge(carry);
        carry.swap(counter[i]);
        ++i;
      }
      carry.swap(counter[i]);
      if (i == fill)
        ++fill;
    }

    for (int i = 1; i < fill; ++i)
      counter[i].merge(counter[i-1]);
    this->swap(counter[fill-1]);
  }
}

#ifdef __STL_MEMBER_TEMPLATES
//移除符合函数pred的结点
template <class T, class Alloc> 
template <class Predicate> void slist<T,Alloc>::remove_if(Predicate pred)
{
  list_node_base* cur = &head;
  while (cur->next) {
    if (pred(((list_node*) cur->next)->data))//如果pred()为真
      erase_after(cur);
    else
      cur = cur->next;
  }
}
//移除满足pred()的结点
template <class T, class Alloc> template <class BinaryPredicate> 
void slist<T,Alloc>::unique(BinaryPredicate pred)
{
  list_node* cur = (list_node*) head.next;
  if (cur) {
    while (cur->next) {
      if (pred(((list_node*)cur)->data, ((list_node*)(cur->next))->data))
        erase_after(cur);
      else
        cur = (list_node*) cur->next;
    }
  }
}
//按照comp函数来合并两个链表。此时两个slist以按照comp排列好了
template <class T, class Alloc> template <class StrictWeakOrdering>
void slist<T,Alloc>::merge(slist<T,Alloc>& L, StrictWeakOrdering comp)
{
  list_node_base* n1 = &head;
  while (n1->next && L.head.next) {
    if (comp(((list_node*) L.head.next)->data,
             ((list_node*) n1->next)->data))
      __slist_splice_after(n1, &L.head, L.head.next);
    n1 = n1->next;
  }
  if (L.head.next) {
    n1->next = L.head.next;
    L.head.next = 0;
  }
}
//按照comp排序
template <class T, class Alloc> template <class StrictWeakOrdering> 
void slist<T,Alloc>::sort(StrictWeakOrdering comp)
{
  if (head.next && head.next->next) {
    slist carry;
    slist counter[64];
    int fill = 0;
    while (!empty()) {
      __slist_splice_after(&carry.head, &head, head.next);
      int i = 0;
      while (i < fill && !counter[i].empty()) {
        counter[i].merge(carry, comp);
        carry.swap(counter[i]);
        ++i;
      }
      carry.swap(counter[i]);
      if (i == fill)
        ++fill;
    }

    for (int i = 1; i < fill; ++i)
      counter[i].merge(counter[i-1], comp);
    this->swap(counter[fill-1]);
  }
}

#endif /* __STL_MEMBER_TEMPLATES */

#if defined(__sgi) && !defined(__GNUC__) && (_MIPS_SIM != _MIPS_SIM_ABI32)
#pragma reset woff 1174
#endif

__STL_END_NAMESPACE 

#endif /* __SGI_STL_INTERNAL_SLIST_H */

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

《STL源码剖析》---stl_slist.h阅读笔记,布布扣,bubuko.com

《STL源码剖析》---stl_slist.h阅读笔记

标签：c++   stl   源码   slist   单向链表   

原文地址：http://blog.csdn.net/kangroger/article/details/38561817