stl_deque.h
stl_deque.h // Filename: stl_deque.h // Comment By: 凝霜 // E-mail: mdl2009@vip.qq.com // Blog: http://blog.csdn.net/mdl13412 // 如果vector能满足你的需求, 那么就使用vector // 如果不得不使用deque, 那么在进行一算法(尤其是sort)操作时 // 应该先把deque中的元素复制到vector中 // 执行完算法再复制回去 // 这样的效率往往要高于直接使用算法的效率 /* * * 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. * * * 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_DEQUE_H #define __SGI_STL_INTERNAL_DEQUE_H // 特性: // 对于任何的非奇异(nonsingular)的迭代器i // i.node是map array中的某元素的地址. i.node的内容是一个指向某个结点的头的指针 // i.first == *(i.node) // i.last == i.first + node_size // i.cur是一个指向[i.first, i.last)之间的指针 // 注意: 这意味着i.cur永远是一个可以解引用的指针, // 即使其是一个指向结尾后元素的迭代器 // // 起点和终点总是非奇异(nonsingular)的迭代器. // 注意: 这意味着空deque一定有一个node, 而一个具有N个元素的deque // (N是Buffer Size)一定有有两个nodes // // 对于除了start.node和finish.node之外的每一个node, 每一个node中的元素 // 都是一个初始化过的对象. 如果start.node == finish.node, // 那么[start.cur, finish.cur)都是未初始化的空间. // 否则, [start.cur, start.last)和[finish.first, finish.cur)都是初始化的对象, // 而[start.first, start.cur)和[finish.cur, finish.last)是未初始化的空间 // // [map, map + map_size)是一个合法的非空区间 // [start.node, finish.node]是内含在[map, map + map_size)区间的合法区间 // 一个在[map, map + map_size)区间内的指针指向一个分配过的node, // 当且仅当此指针在[start.node, finish.node]区间内 // 在前一个版本的deque中, node_size被设定为定植. // 然而在这个版本中, 用户可以自定义node_size的大小. // deque有三个模板参数, 第三个参数为size_t类型, 代表每个结点内的元素数目. // 如果第三个参数被设定为0(默认值), deque使用默认结点大小 // // 使用不同结点大小的唯一理由是, 你的程序需要不同的效率, 并愿意为此付出代价, // 例如, 如果你的程序中有许多deque, 但是每个deque都只包含很少的元素, // 那么你可以使用较小的node_size来进行管理, 但是会对访问操作带来效率损失 // // 不幸的是, 一些编译器不能正确处理non-type template parameters; // 如果这样, 在<stl_config.h>会定义__STL_NON_TYPE_TMPL_PARAM_BUG // 如果你的编译器不幸在列, 你只能使用默认的大小, 而不能更改 __STL_BEGIN_NAMESPACE #if defined(__sgi) && !defined(__GNUC__) && (_MIPS_SIM != _MIPS_SIM_ABI32) #pragma set woff 1174 #endif // 这个函数是为了防止不同编译器在处理常量表达式时的Bug // 如果n != 0, 那么就返回n, 表示buffer size为使用者自定义 // 如果n ==0, 就返回默认值表示buffer size,默认值计算方法如下 // 如果sz(元素类型大小sizeof(type))小于512, 返回512 / sz // 否则返回1 inline size_t __deque_buf_size(size_t n, size_t sz) { return n != 0 ? n : (sz < 512 ? size_t(512 / sz) : size_t(1)); } // 注意这里未继承自std::iterator #ifndef __STL_NON_TYPE_TMPL_PARAM_BUG template <class T, class Ref, class Ptr, size_t BufSiz> struct __deque_iterator { typedef __deque_iterator<T, T&, T*, BufSiz> iterator; typedef __deque_iterator<T, const T&, const T*, BufSiz> const_iterator; static size_t buffer_size() {return __deque_buf_size(BufSiz, sizeof(T)); } #else /* __STL_NON_TYPE_TMPL_PARAM_BUG */ template <class T, class Ref, class Ptr> struct __deque_iterator { typedef __deque_iterator<T, T&, T*> iterator; typedef __deque_iterator<T, const T&, const T*> const_iterator; static size_t buffer_size() {return __deque_buf_size(0, sizeof(T)); } #endif typedef random_access_iterator_tag iterator_category; // STL标准强制要求 typedef T value_type; // STL标准强制要求 typedef Ptr pointer; // STL标准强制要求 typedef Ref reference; // STL标准强制要求 typedef size_t size_type; typedef ptrdiff_t difference_type; // STL标准强制要求 typedef T** map_pointer; typedef __deque_iterator self; // 保存容器中的结点 T* cur; // 指向当前缓冲区中的元素 T* first; // 当前缓冲区的起点 T* last; // 当前缓冲区的终点 //////////////////////////////////////////////////////////////////////////////// // 这个是deque内存管理的关键, 其模型如下 //////////////////////////////////////////////////////////////////////////////// // // --------------------------------------------- // map-->| | | | | | | ..... | | | |<------------------ // --------------------------------------------- | // | | // | | // | node | // | 缓冲区buffer, 这里实际存储元素 | // | --------------------------------------------- | // --->| | | | | | | ..... | | | X | | // --------------------------------------------- | // ↑ ↑ ↑ | // ------ | | | // | | | | // | ----------- --------------------------- | // ----|----- | | // | | | | // | | | | // | | | | // --------------------------- | // | cur | first | end | map |------------------------------ // --------------------------- // 迭代器, 其内部维护着一个缓冲区状态 //////////////////////////////////////////////////////////////////////////////// map_pointer node; __deque_iterator(T* x, map_pointer y) : cur(x), first(*y), last(*y + buffer_size()), node(y) {} __deque_iterator() : cur(0), first(0), last(0), node(0) {} __deque_iterator(const iterator& x) : cur(x.cur), first(x.first), last(x.last), node(x.node) {} reference operator*() const { return *cur; } #ifndef __SGI_STL_NO_ARROW_OPERATOR // 如果编译器支持'->'则重载, 详细见我在<stl_list.h>中的剖析 pointer operator->() const { return &(operator*()); } #endif /* __SGI_STL_NO_ARROW_OPERATOR */ // 判断两个迭代器间的距离 difference_type operator-(const self& x) const { return difference_type(buffer_size()) * (node - x.node - 1) + (cur - first) + (x.last - x.cur); } //////////////////////////////////////////////////////////////////////////////// // 下面重载的这些是运算符是让deque从外界看上去维护的是一段连续空间的关键!!! //////////////////////////////////////////////////////////////////////////////// //////////////////////////////////////////////////////////////////////////////// // 前缀自增 //////////////////////////////////////////////////////////////////////////////// // 如果当前迭代器指向元素是当前缓冲区的最后一个元素, // 则将迭代器状态调整为下一个缓冲区的第一个元素 //////////////////////////////////////////////////////////////////////////////// // 不是当前缓冲区最后一个元素 // // 执行前缀自增前的状态 // first cur end // ↓ ↓ ↓ // --------------------------------------------- // | | | | | | | ..... | | | X | <----- 当前缓冲区 // --------------------------------------------- // // 执行完成后的状态 // first cur end // ↓ ↓ ↓ // --------------------------------------------- // | | | | | | | ..... | | | X | <----- 当前缓冲区 // --------------------------------------------- // //////////////////////////////////////////////////////////////////////////////// // 当前元素为当前缓冲区的最后一个元素 // // 执行前缀自增前的状态 // first cur end // ↓ ↓ ↓ // --------------------------------------------- // | | | | | | | ..... | | | X | <----- 当前缓冲区 // --------------------------------------------- // // 执行完成后的状态 // first end // ↓ ↓ // --------------------------------------------- // | | | | | | | ..... | | | X | <----- 下一缓冲区 // --------------------------------------------- // ↑ // cur // //////////////////////////////////////////////////////////////////////////////// self& operator++() { ++cur; if (cur == last) { set_node(node + 1); cur = first; } return *this; } // 后缀自增 // 返回当前迭代器的一个副本, 并调用前缀自增运算符实现迭代器自身的自增 self operator++(int) { self tmp = *this; ++*this; return tmp; } // 前缀自减, 处理方式类似于前缀自增 // 如果当前迭代器指向元素是当前缓冲区的第一个元素 // 则将迭代器状态调整为前一个缓冲区的最后一个元素 self& operator--() { if (cur == first) { set_node(node - 1); cur = last; } --cur; return *this; } self operator--(int) { self tmp = *this; --*this; return tmp; } //////////////////////////////////////////////////////////////////////////////// // 将迭代器向前移动n个元素, n可以为负 //////////////////////////////////////////////////////////////////////////////// // operator+=(difference_type n) // ↓ // offset = n + (cur - first) // | // |---------- offset > 0 ? && // | 移动后是否超出当前缓冲区? // ---------------------------- // No | | Yes // | | // ↓ |---------- offset > 0? // cur += n; | // ---------------------------- // Yes | | No // | | // ↓ | // 计算要向后移动多少个缓冲区 | // node_offset = | // offset / difference_type | // (buffer_size()); ↓ // | 计算要向前移动多少个缓冲区 // | node_offset = -difference_type // | ((-offset - 1) / buffer_size()) - 1; // | | // ---------------------------- // | // | // ↓ // 调整缓冲区 // set_node(node + node_offset); // 计算并调整cur指针 //////////////////////////////////////////////////////////////////////////////// self& operator+=(difference_type n) { difference_type offset = n + (cur - first); if (offset >= 0 && offset < difference_type(buffer_size())) cur += n; else { difference_type node_offset = offset > 0 ? offset / difference_type(buffer_size()) : -difference_type((-offset - 1) / buffer_size()) - 1; set_node(node + node_offset); cur = first + (offset - node_offset * difference_type(buffer_size())); } return *this; } self operator+(difference_type n) const { self tmp = *this; // 这里调用了operator +=()可以自动调整指针状态 return tmp += n; } // :-), 将n变为-n就可以使用operator +=()了, // 初等数学是神奇的, 还记得我们刚学编程时求绝对值是怎么写的吗? :P self& operator-=(difference_type n) { return *this += -n; } self operator-(difference_type n) const { self tmp = *this; return tmp -= n; } reference operator[](difference_type n) const { return *(*this + n); } bool operator==(const self& x) const { return cur == x.cur; } bool operator!=(const self& x) const { return !(*this == x); } bool operator<(const self& x) const { return (node == x.node) ? (cur < x.cur) : (node < x.node); } void set_node(map_pointer new_node) { node = new_node; first = *new_node; last = first + difference_type(buffer_size()); } }; #ifndef __STL_CLASS_PARTIAL_SPECIALIZATION #ifndef __STL_NON_TYPE_TMPL_PARAM_BUG template <class T, class Ref, class Ptr, size_t BufSiz> inline random_access_iterator_tag iterator_category(const __deque_iterator<T, Ref, Ptr, BufSiz>&) { return random_access_iterator_tag(); } template <class T, class Ref, class Ptr, size_t BufSiz> inline T* value_type(const __deque_iterator<T, Ref, Ptr, BufSiz>&) { return 0; } template <class T, class Ref, class Ptr, size_t BufSiz> inline ptrdiff_t* distance_type(const __deque_iterator<T, Ref, Ptr, BufSiz>&) { return 0; } #else /* __STL_NON_TYPE_TMPL_PARAM_BUG */ template <class T, class Ref, class Ptr> inline random_access_iterator_tag iterator_category(const __deque_iterator<T, Ref, Ptr>&) { return random_access_iterator_tag(); } template <class T, class Ref, class Ptr> inline T* value_type(const __deque_iterator<T, Ref, Ptr>&) { return 0; } template <class T, class Ref, class Ptr> inline ptrdiff_t* distance_type(const __deque_iterator<T, Ref, Ptr>&) { return 0; } #endif /* __STL_NON_TYPE_TMPL_PARAM_BUG */ // 其实剖析到这里就没有什么难的了, deque的运算符才是核心 #endif /* __STL_CLASS_PARTIAL_SPECIALIZATION */ // See __deque_buf_size(). The only reason that the default value is 0 // is as a workaround for bugs in the way that some compilers handle // constant expressions. template <class T, class Alloc = alloc, size_t BufSiz = 0> class deque { public: // Basic types 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; public: // Iterators #ifndef __STL_NON_TYPE_TMPL_PARAM_BUG typedef __deque_iterator<T, T&, T*, BufSiz> iterator; typedef __deque_iterator<T, const T&, const T&, BufSiz> const_iterator; #else /* __STL_NON_TYPE_TMPL_PARAM_BUG */ typedef __deque_iterator<T, T&, T*> iterator; typedef __deque_iterator<T, const T&, const T*> const_iterator; #endif /* __STL_NON_TYPE_TMPL_PARAM_BUG */ #ifdef __STL_CLASS_PARTIAL_SPECIALIZATION typedef reverse_iterator<const_iterator> const_reverse_iterator; typedef reverse_iterator<iterator> reverse_iterator; #else /* __STL_CLASS_PARTIAL_SPECIALIZATION */ typedef reverse_iterator<const_iterator, value_type, const_reference, difference_type> const_reverse_iterator; typedef reverse_iterator<iterator, value_type, reference, difference_type> reverse_iterator; #endif /* __STL_CLASS_PARTIAL_SPECIALIZATION */ protected: // Internal typedefs typedef pointer* map_pointer; // 这个提供STL标准的allocator接口, 见<stl_alloc.h> typedef simple_alloc<value_type, Alloc> data_allocator; typedef simple_alloc<pointer, Alloc> map_allocator; // 获取缓冲区最大存储元素数量 static size_type buffer_size() { return __deque_buf_size(BufSiz, sizeof(value_type)); } static size_type initial_map_size() { return 8; } protected: // Data members iterator start; // 起始缓冲区 iterator finish; // 最后一个缓冲区 // 指向map, map是一个连续的空间, 其每个元素都是一个指向缓冲区的指针 // 其模型见前面的__deque_iterator map_pointer map; size_type map_size; // map容量 public: // Basic accessors iterator begin() { return start; } iterator end() { return finish; } const_iterator begin() const { return start; } const_iterator end() const { return finish; } reverse_iterator rbegin() { return reverse_iterator(finish); } reverse_iterator rend() { return reverse_iterator(start); } const_reverse_iterator rbegin() const { return const_reverse_iterator(finish); } const_reverse_iterator rend() const { return const_reverse_iterator(start); } // 提供随机访问能力, 其调用的是迭代器重载的operator [] // 其实际地址需要进行一些列的计算, 效率有损失 reference operator[](size_type n) { return start[difference_type(n)]; } const_reference operator[](size_type n) const { return start[difference_type(n)]; } reference front() { return *start; } reference back() { iterator tmp = finish; --tmp; return *tmp; } const_reference front() const { return *start; } const_reference back() const { const_iterator tmp = finish; --tmp; return *tmp; } // 当前容器拥有的元素个数, 调用迭代器重载的operator - size_type size() const { return finish - start;; } size_type max_size() const { return size_type(-1); } // deque为空的时, 只有一个缓冲区 bool empty() const { return finish == start; } public: // Constructor, destructor. deque() : start(), finish(), map(0), map_size(0) { create_map_and_nodes(0); } // 注: commit or rollback deque(const deque& x) : start(), finish(), map(0), map_size(0) { create_map_and_nodes(x.size()); __STL_TRY { uninitialized_copy(x.begin(), x.end(), start); // <stl_uninitialized.h> } __STL_UNWIND(destroy_map_and_nodes()); } deque(size_type n, const value_type& value) : start(), finish(), map(0), map_size(0) { fill_initialize(n, value); } deque(int n, const value_type& value) : start(), finish(), map(0), map_size(0) { fill_initialize(n, value); } deque(long n, const value_type& value) : start(), finish(), map(0), map_size(0) { fill_initialize(n, value); } explicit deque(size_type n) : start(), finish(), map(0), map_size(0) { fill_initialize(n, value_type()); } #ifdef __STL_MEMBER_TEMPLATES template <class InputIterator> deque(InputIterator first, InputIterator last) : start(), finish(), map(0), map_size(0) { range_initialize(first, last, iterator_category(first)); } #else /* __STL_MEMBER_TEMPLATES */ deque(const value_type* first, const value_type* last) : start(), finish(), map(0), map_size(0) { create_map_and_nodes(last - first); __STL_TRY { uninitialized_copy(first, last, start); } __STL_UNWIND(destroy_map_and_nodes()); } deque(const_iterator first, const_iterator last) : start(), finish(), map(0), map_size(0) { create_map_and_nodes(last - first); __STL_TRY { uninitialized_copy(first, last, start); } __STL_UNWIND(destroy_map_and_nodes()); } #endif /* __STL_MEMBER_TEMPLATES */ ~deque() { destroy(start, finish); // <stl_construct.h> destroy_map_and_nodes(); } deque& operator= (const deque& x) { // 其实我觉得把这个操作放在if内效率更高 const size_type len = size(); if (&x != this) { // 当前容器比x容器拥有元素多, 析构多余元素 if (len >= x.size()) erase(copy(x.begin(), x.end(), start), finish); // 将x所有超出部分的元素使用insert()追加进去 else { const_iterator mid = x.begin() + difference_type(len); copy(x.begin(), mid, start); insert(finish, mid, x.end()); } } return *this; } // 其实要交换两个容器, 只需要交换其内部维护的指针即可^_^ void swap(deque& x) { __STD::swap(start, x.start); __STD::swap(finish, x.finish); __STD::swap(map, x.map); __STD::swap(map_size, x.map_size); } public: // push_* and pop_* void push_back(const value_type& t) { // STL使用前闭后开的区间, 所以如果还有剩余容量, // 则直接在finish.cur上构造对象即可, 然后更新迭代器 if (finish.cur != finish.last - 1) { construct(finish.cur, t); ++finish.cur; } // 容量已满就要新申请内存了 else push_back_aux(t); } void push_front(const value_type& t) { if (start.cur != start.first) { construct(start.cur - 1, t); --start.cur; } else push_front_aux(t); } void pop_back() { if (finish.cur != finish.first) { --finish.cur; destroy(finish.cur); } else pop_back_aux(); } void pop_front() { if (start.cur != start.last - 1) { destroy(start.cur); ++start.cur; } else pop_front_aux(); } public: // Insert //////////////////////////////////////////////////////////////////////////////// // 在指定位置前插入元素 //////////////////////////////////////////////////////////////////////////////// // insert(iterator position, const value_type& x) // | // |---------------- 判断插入位置 // | // ----------------------------------------------- // deque.begin() | deque.emd() | | // | | | // ↓ ↓ | // push_front(x); push_back(x); | // ↓ // insert_aux(position, x); // 具体剖析见后面实现 //////////////////////////////////////////////////////////////////////////////// iterator insert(iterator position, const value_type& x) { // 如果是在deque的最前端插入, 那么直接push_front()即可 if (position.cur == start.cur) { push_front(x); return start; } // 如果是在deque的末尾插入, 直接调用push_back() else if (position.cur == finish.cur) { push_back(x); iterator tmp = finish; --tmp; return tmp; } else { return insert_aux(position, x); } } iterator insert(iterator position) { return insert(position, value_type()); } // 详解见实现部分 void insert(iterator pos, size_type n, const value_type& x); void insert(iterator pos, int n, const value_type& x) { insert(pos, (size_type) n, x); } void insert(iterator pos, long n, const value_type& x) { insert(pos, (size_type) n, x); } #ifdef __STL_MEMBER_TEMPLATES template <class InputIterator> void insert(iterator pos, InputIterator first, InputIterator last) { insert(pos, first, last, iterator_category(first)); } #else /* __STL_MEMBER_TEMPLATES */ void insert(iterator pos, const value_type* first, const value_type* last); void insert(iterator pos, const_iterator first, const_iterator last); #endif /* __STL_MEMBER_TEMPLATES */ // 如果new_size < size(), 那么就析构掉多余的元素, // 否则以x为蓝本进行剩余元素的填充 void resize(size_type new_size, const value_type& x) { const size_type len = size(); if (new_size < len) erase(start + new_size, finish); else insert(finish, new_size - len, x); } void resize(size_type new_size) { resize(new_size, value_type()); } public: // Erase iterator erase(iterator pos) { iterator next = pos; ++next; // 计算待擦除点前的元素个数 difference_type index = pos - start; // 判断待擦除结点前后元素的个数, 哪部分少就移动哪部分 if (index < (size() >> 1)) { // 前面部分的元素少 copy_backward(start, pos, next); // <stl_algobase.h> pop_front(); } // 后面部分的元素少 else { copy(next, finish, pos); // <stl_algobase.h> pop_back(); } return start + index; } // 详解见实现部分 iterator erase(iterator first, iterator last); void clear(); protected: // Internal construction/destruction // 详解见实现部分 void create_map_and_nodes(size_type num_elements); void destroy_map_and_nodes(); void fill_initialize(size_type n, const value_type& value); #ifdef __STL_MEMBER_TEMPLATES template <class InputIterator> void range_initialize(InputIterator first, InputIterator last, input_iterator_tag); template <class ForwardIterator> void range_initialize(ForwardIterator first, ForwardIterator last, forward_iterator_tag); #endif /* __STL_MEMBER_TEMPLATES */ protected: // Internal push_* and pop_* // 详解见实现部分 void push_back_aux(const value_type& t); void push_front_aux(const value_type& t); void pop_back_aux(); void pop_front_aux(); protected: // Internal insert functions #ifdef __STL_MEMBER_TEMPLATES template <class InputIterator> void insert(iterator pos, InputIterator first, InputIterator last, input_iterator_tag); template <class ForwardIterator> void insert(iterator pos, ForwardIterator first, ForwardIterator last, forward_iterator_tag); #endif /* __STL_MEMBER_TEMPLATES */ iterator insert_aux(iterator pos, const value_type& x); void insert_aux(iterator pos, size_type n, const value_type& x); #ifdef __STL_MEMBER_TEMPLATES template <class ForwardIterator> void insert_aux(iterator pos, ForwardIterator first, ForwardIterator last, size_type n); #else /* __STL_MEMBER_TEMPLATES */ void insert_aux(iterator pos, const value_type* first, const value_type* last, size_type n); void insert_aux(iterator pos, const_iterator first, const_iterator last, size_type n); #endif /* __STL_MEMBER_TEMPLATES */ // 在起始缓冲区预留大小为n的空间 // 如果缓冲区不足则重新分配 iterator reserve_elements_at_front(size_type n) { size_type vacancies = start.cur - start.first; if (n > vacancies) new_elements_at_front(n - vacancies); return start - difference_type(n); } iterator reserve_elements_at_back(size_type n) { size_type vacancies = (finish.last - finish.cur) - 1; if (n > vacancies) new_elements_at_back(n - vacancies); return finish + difference_type(n); } void new_elements_at_front(size_type new_elements); void new_elements_at_back(size_type new_elements); void destroy_nodes_at_front(iterator before_start); void destroy_nodes_at_back(iterator after_finish); protected: // Allocation of map and nodes // Makes sure the map has space for new nodes. Does not actually // add the nodes. Can invalidate map pointers. (And consequently, // deque iterators.) void reserve_map_at_back (size_type nodes_to_add = 1) { if (nodes_to_add + 1 > map_size - (finish.node - map)) reallocate_map(nodes_to_add, false); } void reserve_map_at_front (size_type nodes_to_add = 1) { if (nodes_to_add > start.node - map) reallocate_map(nodes_to_add, true); } void reallocate_map(size_type nodes_to_add, bool add_at_front); // 分配内存, 不进行构造 pointer allocate_node() { return data_allocator::allocate(buffer_size()); } // 释放内存, 不进行析构 void deallocate_node(pointer n) { data_allocator::deallocate(n, buffer_size()); } #ifdef __STL_NON_TYPE_TMPL_PARAM_BUG public: bool operator==(const deque<T, Alloc, 0>& x) const { return size() == x.size() && equal(begin(), end(), x.begin()); } bool operator!=(const deque<T, Alloc, 0>& x) const { return size() != x.size() || !equal(begin(), end(), x.begin()); } bool operator<(const deque<T, Alloc, 0>& x) const { return lexicographical_compare(begin(), end(), x.begin(), x.end()); } #endif /* __STL_NON_TYPE_TMPL_PARAM_BUG */ }; //////////////////////////////////////////////////////////////////////////////// // 不进行内联的成员函数 //////////////////////////////////////////////////////////////////////////////// //////////////////////////////////////////////////////////////////////////////// // 在指定位置前插入n个值为x的元素 //////////////////////////////////////////////////////////////////////////////// // insert(iterator pos, size_type n, const value_type& x) // | // |---------------- 判断插入位置 // | // --------------------------------------------------------- // deque.begin() | deque.end() | | // | | | // ↓ | | // reserve_elements_at_front(n); | | // uninitialized_fill(new_start, start, x); | | // ↓ | // reserve_elements_at_back(n); | // uninitialized_fill(finish, new_finish, x); | // ↓ // insert_aux(pos, n, x); // 剖析见后面实现 //////////////////////////////////////////////////////////////////////////////// template <class T, class Alloc, size_t BufSize> void deque<T, Alloc, BufSize>::insert(iterator pos, size_type n, const value_type& x) { if (pos.cur == start.cur) { iterator new_start = reserve_elements_at_front(n); uninitialized_fill(new_start, start, x); start = new_start; } else if (pos.cur == finish.cur) { iterator new_finish = reserve_elements_at_back(n); uninitialized_fill(finish, new_finish, x); finish = new_finish; } else insert_aux(pos, n, x); } // 给不支持成员函数模板的编译器提供支持函数 #ifndef __STL_MEMBER_TEMPLATES template <class T, class Alloc, size_t BufSize> void deque<T, Alloc, BufSize>::insert(iterator pos, const value_type* first, const value_type* last) { size_type n = last - first; if (pos.cur == start.cur) { iterator new_start = reserve_elements_at_front(n); __STL_TRY { uninitialized_copy(first, last, new_start); start = new_start; } __STL_UNWIND(destroy_nodes_at_front(new_start)); } else if (pos.cur == finish.cur) { iterator new_finish = reserve_elements_at_back(n); __STL_TRY { uninitialized_copy(first, last, finish); finish = new_finish; } __STL_UNWIND(destroy_nodes_at_back(new_finish)); } else insert_aux(pos, first, last, n); } template <class T, class Alloc, size_t BufSize> void deque<T, Alloc, BufSize>::insert(iterator pos, const_iterator first, const_iterator last) { size_type n = last - first; if (pos.cur == start.cur) { iterator new_start = reserve_elements_at_front(n); __STL_TRY { uninitialized_copy(first, last, new_start); start = new_start; } __STL_UNWIND(destroy_nodes_at_front(new_start)); } else if (pos.cur == finish.cur) { iterator new_finish = reserve_elements_at_back(n); __STL_TRY { uninitialized_copy(first, last, finish); finish = new_finish; } __STL_UNWIND(destroy_nodes_at_back(new_finish)); } else insert_aux(pos, first, last, n); } #endif /* __STL_MEMBER_TEMPLATES */ //////////////////////////////////////////////////////////////////////////////// // 擦除[first, last)区间的元素 //////////////////////////////////////////////////////////////////////////////// // erase(iterator first, iterator last) // | // |---------------- 是否要删除整个区间? // | // ------------------------------------------ // Yes | | No // | | // ↓ | --- 判断哪侧元素少 // clear(); ↓ // ----------------------------------------------------------------- // 左侧少 | 右侧少 | // | | // ↓ ↓ // copy_backward(start, first, last); copy(last, finish, first); // new_start = start + n; new_finish = finish - n; // 析构多余的元素 析构多余的元素 // destroy(start, new_start); destroy(new_finish, finish); // 释放多余内存空间 释放多余内存空间 // for (...) for (...) // ... ... // 更新map状态 更新map状态 //////////////////////////////////////////////////////////////////////////////// template <class T, class Alloc, size_t BufSize> deque<T, Alloc, BufSize>::iterator deque<T, Alloc, BufSize>::erase(iterator first, iterator last) { if (first == start && last == finish) { clear(); return finish; } else { difference_type n = last - first; difference_type elems_before = first - start; if (elems_before < (size() - n) / 2) { copy_backward(start, first, last); iterator new_start = start + n; destroy(start, new_start); for (map_pointer cur = start.node; cur < new_start.node; ++cur) data_allocator::deallocate(*cur, buffer_size()); start = new_start; } else { copy(last, finish, first); iterator new_finish = finish - n; destroy(new_finish, finish); for (map_pointer cur = new_finish.node + 1; cur <= finish.node; ++cur) data_allocator::deallocate(*cur, buffer_size()); finish = new_finish; } return start + elems_before; } } template <class T, class Alloc, size_t BufSize> void deque<T, Alloc, BufSize>::clear() { // 首先析构除起点和终点的所有元素, 并释放相应空间 for (map_pointer node = start.node + 1; node < finish.node; ++node) { destroy(*node, *node + buffer_size()); data_allocator::deallocate(*node, buffer_size()); } // 如果deque本身不为空, 析构所有对象, 并释放掉结尾的内存 if (start.node != finish.node) { destroy(start.cur, start.last); destroy(finish.first, finish.cur); data_allocator::deallocate(finish.first, buffer_size()); } // 析构所有元素, 但是不释放空间, 因为deque要满足这个前置条件 // 具体的细节见本文件开头'特性' else destroy(start.cur, finish.cur); finish = start; } // 创建内部使用的map template <class T, class Alloc, size_t BufSize> void deque<T, Alloc, BufSize>::create_map_and_nodes(size_type num_elements) { // 需要的结点数, 元素个数 / 每个缓冲区能容纳的元素数 + 1 size_type num_nodes = num_elements / buffer_size() + 1; // map要维护的结点, 这里最小的值为8, 见initial_map_size() map_size = max(initial_map_size(), num_nodes + 2); map = map_allocator::allocate(map_size); // 将[nstart, nfinish)区间设置在map的中间, // 这样就能保证前后增长而尽可能减少map的重新分配次数 map_pointer nstart = map + (map_size - num_nodes) / 2; map_pointer nfinish = nstart + num_nodes - 1; // 分配结点空间 map_pointer cur; __STL_TRY { for (cur = nstart; cur <= nfinish; ++cur) *cur = allocate_node(); } # ifdef __STL_USE_EXCEPTIONS catch(...) { for (map_pointer n = nstart; n < cur; ++n) deallocate_node(*n); map_allocator::deallocate(map, map_size); throw; } # endif /* __STL_USE_EXCEPTIONS */ // 维护指针状态 start.set_node(nstart); finish.set_node(nfinish); start.cur = start.first; finish.cur = finish.first + num_elements % buffer_size(); } // This is only used as a cleanup function in catch clauses. template <class T, class Alloc, size_t BufSize> void deque<T, Alloc, BufSize>::destroy_map_and_nodes() { for (map_pointer cur = start.node; cur <= finish.node; ++cur) deallocate_node(*cur); map_allocator::deallocate(map, map_size); } // 分配n个结点, 并以value为蓝本初始化 template <class T, class Alloc, size_t BufSize> void deque<T, Alloc, BufSize>::fill_initialize(size_type n, const value_type& value) { create_map_and_nodes(n); map_pointer cur; __STL_TRY { for (cur = start.node; cur < finish.node; ++cur) uninitialized_fill(*cur, *cur + buffer_size(), value); uninitialized_fill(finish.first, finish.cur, value); } # ifdef __STL_USE_EXCEPTIONS catch(...) { for (map_pointer n = start.node; n < cur; ++n) destroy(*n, *n + buffer_size()); destroy_map_and_nodes(); throw; } # endif /* __STL_USE_EXCEPTIONS */ } #ifdef __STL_MEMBER_TEMPLATES template <class T, class Alloc, size_t BufSize> template <class InputIterator> void deque<T, Alloc, BufSize>::range_initialize(InputIterator first, InputIterator last, input_iterator_tag) { create_map_and_nodes(0); for ( ; first != last; ++first) push_back(*first); } template <class T, class Alloc, size_t BufSize> template <class ForwardIterator> void deque<T, Alloc, BufSize>::range_initialize(ForwardIterator first, ForwardIterator last, forward_iterator_tag) { size_type n = 0; distance(first, last, n); create_map_and_nodes(n); __STL_TRY { uninitialized_copy(first, last, start); } __STL_UNWIND(destroy_map_and_nodes()); } #endif /* __STL_MEMBER_TEMPLATES */ // 仅当finish.cur == finish.last - 1才调用 // 即最后一个缓冲区没有空间才调用 template <class T, class Alloc, size_t BufSize> void deque<T, Alloc, BufSize>::push_back_aux(const value_type& t) { value_type t_copy = t; reserve_map_at_back(); *(finish.node + 1) = allocate_node(); __STL_TRY { construct(finish.cur, t_copy); finish.set_node(finish.node + 1); finish.cur = finish.first; } __STL_UNWIND(deallocate_node(*(finish.node + 1))); } // Called only if start.cur == start.first. template <class T, class Alloc, size_t BufSize> void deque<T, Alloc, BufSize>::push_front_aux(const value_type& t) { value_type t_copy = t; reserve_map_at_front(); *(start.node - 1) = allocate_node(); __STL_TRY { start.set_node(start.node - 1); start.cur = start.last - 1; construct(start.cur, t_copy); } # ifdef __STL_USE_EXCEPTIONS catch(...) { start.set_node(start.node + 1); start.cur = start.first; deallocate_node(*(start.node - 1)); throw; } # endif /* __STL_USE_EXCEPTIONS */ } // Called only if finish.cur == finish.first. template <class T, class Alloc, size_t BufSize> void deque<T, Alloc, BufSize>:: pop_back_aux() { deallocate_node(finish.first); finish.set_node(finish.node - 1); finish.cur = finish.last - 1; destroy(finish.cur); } // Called only if start.cur == start.last - 1. Note that if the deque // has at least one element (a necessary precondition for this member // function), and if start.cur == start.last, then the deque must have // at least two nodes. template <class T, class Alloc, size_t BufSize> void deque<T, Alloc, BufSize>::pop_front_aux() { destroy(start.cur); deallocate_node(start.first); start.set_node(start.node + 1); start.cur = start.first; } #ifdef __STL_MEMBER_TEMPLATES // 将[first, last)区间元素插入到pos前 template <class T, class Alloc, size_t BufSize> template <class InputIterator> void deque<T, Alloc, BufSize>::insert(iterator pos, InputIterator first, InputIterator last, input_iterator_tag) { // 由于是Input Iterator, 则使用通用的inserter完成插入操作 copy(first, last, inserter(*this, pos)); } template <class T, class Alloc, size_t BufSize> template <class ForwardIterator> void deque<T, Alloc, BufSize>::insert(iterator pos, ForwardIterator first, ForwardIterator last, forward_iterator_tag) { size_type n = 0; distance(first, last, n); if (pos.cur == start.cur) { iterator new_start = reserve_elements_at_front(n); __STL_TRY { uninitialized_copy(first, last, new_start); start = new_start; } __STL_UNWIND(destroy_nodes_at_front(new_start)); } else if (pos.cur == finish.cur) { iterator new_finish = reserve_elements_at_back(n); __STL_TRY { uninitialized_copy(first, last, finish); finish = new_finish; } __STL_UNWIND(destroy_nodes_at_back(new_finish)); } else insert_aux(pos, first, last, n); } #endif /* __STL_MEMBER_TEMPLATES */ //////////////////////////////////////////////////////////////////////////////// // 在指定位置前插入元素 //////////////////////////////////////////////////////////////////////////////// // insert_aux(iterator pos, const value_type& x) // | // |----------- 判断pos前端元素少还是后端元素少 // | // ----------------------------------------------- // 前端少 | 后端少 | // | | // ↓ | // 进行相关操作 进行相关操作 //////////////////////////////////////////////////////////////////////////////// // 下面以pos前面元素少的情形进行说明, 为了简化, 假设操作不会超过一个缓冲区区间 // // 插入前状态 // start pos end // ↓ ↓ ↓ // --------------------------------------------------------------------- // | | | | | | | | | | | | | | | | | X | // --------------------------------------------------------------------- // // 需要进行操作的区间 // 需要拷贝的区间 // ------------- // start | | end // ↓ ↓ ↓ ↓ // --------------------------------------------------------------------- // | | | | | | | | | | | | | | | | | X | // --------------------------------------------------------------------- // ↑ ↑ ↑ ↑ // front1 | | | // | | | // front2 | | // | | // pos | // | // pos1 // 拷贝操作完成后 // // 这是[front2, pos1) // ------------- --------- 这里是给待插入元素预留的空间 // start | | | end // ↓ ↓ ↓ ↓ ↓ // --------------------------------------------------------------------- // | | | | | | | | | | | | | | | | | X | // --------------------------------------------------------------------- // ↑ // 这里存储的是原来的front() // //////////////////////////////////////////////////////////////////////////////// template <class T, class Alloc, size_t BufSize> typename deque<T, Alloc, BufSize>::iterator deque<T, Alloc, BufSize>::insert_aux(iterator pos, const value_type& x) { difference_type index = pos - start; value_type x_copy = x; // 前面的时候用的移位操作, 这里怎么不用了呢^_^? if (index < size() / 2) { push_front(front()); iterator front1 = start; ++front1; iterator front2 = front1; ++front2; pos = start + index; iterator pos1 = pos; ++pos1; copy(front2, pos1, front1); } else { push_back(back()); iterator back1 = finish; --back1; iterator back2 = back1; --back2; pos = start + index; copy_backward(pos, back2, back1); } *pos = x_copy; return pos; } //////////////////////////////////////////////////////////////////////////////// // 在pos前插入n个值为x的元素 //////////////////////////////////////////////////////////////////////////////// // insert_aux(iterator pos, size_type n, const value_type& x) // ↓ // elems_before = pos - start; // length = size(); // | // |---------- elems_before < length / 2 ? // | 判断哪侧元素少, 就对哪侧进行操作 // --------------------------------------- // Yes | | No // | | // ↓ ↓ // reserve_elements_at_front(n); reserve_elements_at_back(n); // 根据具体情况进行元素的拷贝操作 根据具体情况进行元素的拷贝操作 //////////////////////////////////////////////////////////////////////////////// template <class T, class Alloc, size_t BufSize> void deque<T, Alloc, BufSize>::insert_aux(iterator pos, size_type n, const value_type& x) { const difference_type elems_before = pos - start; size_type length = size(); value_type x_copy = x; if (elems_before < length / 2) { iterator new_start = reserve_elements_at_front(n); iterator old_start = start; pos = start + elems_before; __STL_TRY { if (elems_before >= difference_type(n)) { iterator start_n = start + difference_type(n); uninitialized_copy(start, start_n, new_start); start = new_start; copy(start_n, pos, old_start); fill(pos - difference_type(n), pos, x_copy); } else { __uninitialized_copy_fill(start, pos, new_start, start, x_copy); start = new_start; fill(old_start, pos, x_copy); } } __STL_UNWIND(destroy_nodes_at_front(new_start)); } else { iterator new_finish = reserve_elements_at_back(n); iterator old_finish = finish; const difference_type elems_after = difference_type(length) - elems_before; pos = finish - elems_after; __STL_TRY { if (elems_after > difference_type(n)) { iterator finish_n = finish - difference_type(n); uninitialized_copy(finish_n, finish, finish); finish = new_finish; copy_backward(pos, finish_n, old_finish); fill(pos, pos + difference_type(n), x_copy); } else { __uninitialized_fill_copy(finish, pos + difference_type(n), x_copy, pos, finish); finish = new_finish; fill(pos, old_finish, x_copy); } } __STL_UNWIND(destroy_nodes_at_back(new_finish)); } } #ifdef __STL_MEMBER_TEMPLATES // 供给insert(iterator pos, ForwardIterator first, ForwardIterator last,) // 处理通用情况 template <class T, class Alloc, size_t BufSize> template <class ForwardIterator> void deque<T, Alloc, BufSize>::insert_aux(iterator pos, ForwardIterator first, ForwardIterator last, size_type n) { const difference_type elems_before = pos - start; size_type length = size(); if (elems_before < length / 2) { iterator new_start = reserve_elements_at_front(n); iterator old_start = start; pos = start + elems_before; __STL_TRY { if (elems_before >= difference_type(n)) { iterator start_n = start + difference_type(n); uninitialized_copy(start, start_n, new_start); start = new_start; copy(start_n, pos, old_start); copy(first, last, pos - difference_type(n)); } else { ForwardIterator mid = first; advance(mid, difference_type(n) - elems_before); __uninitialized_copy_copy(start, pos, first, mid, new_start); start = new_start; copy(mid, last, old_start); } } __STL_UNWIND(destroy_nodes_at_front(new_start)); } else { iterator new_finish = reserve_elements_at_back(n); iterator old_finish = finish; const difference_type elems_after = difference_type(length) - elems_before; pos = finish - elems_after; __STL_TRY { if (elems_after > difference_type(n)) { iterator finish_n = finish - difference_type(n); uninitialized_copy(finish_n, finish, finish); finish = new_finish; copy_backward(pos, finish_n, old_finish); copy(first, last, pos); } else { ForwardIterator mid = first; advance(mid, elems_after); __uninitialized_copy_copy(mid, last, pos, finish, finish); finish = new_finish; copy(first, mid, pos); } } __STL_UNWIND(destroy_nodes_at_back(new_finish)); } } #else /* __STL_MEMBER_TEMPLATES */ template <class T, class Alloc, size_t BufSize> void deque<T, Alloc, BufSize>::insert_aux(iterator pos, const value_type* first, const value_type* last, size_type n) { const difference_type elems_before = pos - start; size_type length = size(); if (elems_before < length / 2) { iterator new_start = reserve_elements_at_front(n); iterator old_start = start; pos = start + elems_before; __STL_TRY { if (elems_before >= difference_type(n)) { iterator start_n = start + difference_type(n); uninitialized_copy(start, start_n, new_start); start = new_start; copy(start_n, pos, old_start); copy(first, last, pos - difference_type(n)); } else { const value_type* mid = first + (difference_type(n) - elems_before); __uninitialized_copy_copy(start, pos, first, mid, new_start); start = new_start; copy(mid, last, old_start); } } __STL_UNWIND(destroy_nodes_at_front(new_start)); } else { iterator new_finish = reserve_elements_at_back(n); iterator old_finish = finish; const difference_type elems_after = difference_type(length) - elems_before; pos = finish - elems_after; __STL_TRY { if (elems_after > difference_type(n)) { iterator finish_n = finish - difference_type(n); uninitialized_copy(finish_n, finish, finish); finish = new_finish; copy_backward(pos, finish_n, old_finish); copy(first, last, pos); } else { const value_type* mid = first + elems_after; __uninitialized_copy_copy(mid, last, pos, finish, finish); finish = new_finish; copy(first, mid, pos); } } __STL_UNWIND(destroy_nodes_at_back(new_finish)); } } template <class T, class Alloc, size_t BufSize> void deque<T, Alloc, BufSize>::insert_aux(iterator pos, const_iterator first, const_iterator last, size_type n) { const difference_type elems_before = pos - start; size_type length = size(); if (elems_before < length / 2) { iterator new_start = reserve_elements_at_front(n); iterator old_start = start; pos = start + elems_before; __STL_TRY { if (elems_before >= n) { iterator start_n = start + n; uninitialized_copy(start, start_n, new_start); start = new_start; copy(start_n, pos, old_start); copy(first, last, pos - difference_type(n)); } else { const_iterator mid = first + (n - elems_before); __uninitialized_copy_copy(start, pos, first, mid, new_start); start = new_start; copy(mid, last, old_start); } } __STL_UNWIND(destroy_nodes_at_front(new_start)); } else { iterator new_finish = reserve_elements_at_back(n); iterator old_finish = finish; const difference_type elems_after = length - elems_before; pos = finish - elems_after; __STL_TRY { if (elems_after > n) { iterator finish_n = finish - difference_type(n); uninitialized_copy(finish_n, finish, finish); finish = new_finish; copy_backward(pos, finish_n, old_finish); copy(first, last, pos); } else { const_iterator mid = first + elems_after; __uninitialized_copy_copy(mid, last, pos, finish, finish); finish = new_finish; copy(first, mid, pos); } } __STL_UNWIND(destroy_nodes_at_back(new_finish)); } } #endif /* __STL_MEMBER_TEMPLATES */ // 在deque前端分配新结点 template <class T, class Alloc, size_t BufSize> void deque<T, Alloc, BufSize>::new_elements_at_front(size_type new_elements) { size_type new_nodes = (new_elements + buffer_size() - 1) / buffer_size(); reserve_map_at_front(new_nodes); size_type i; __STL_TRY { for (i = 1; i <= new_nodes; ++i) *(start.node - i) = allocate_node(); } # ifdef __STL_USE_EXCEPTIONS catch(...) { for (size_type j = 1; j < i; ++j) deallocate_node(*(start.node - j)); throw; } # endif /* __STL_USE_EXCEPTIONS */ } // 在deque末尾分配新结点 template <class T, class Alloc, size_t BufSize> void deque<T, Alloc, BufSize>::new_elements_at_back(size_type new_elements) { size_type new_nodes = (new_elements + buffer_size() - 1) / buffer_size(); reserve_map_at_back(new_nodes); size_type i; __STL_TRY { for (i = 1; i <= new_nodes; ++i) *(finish.node + i) = allocate_node(); } # ifdef __STL_USE_EXCEPTIONS catch(...) { for (size_type j = 1; j < i; ++j) deallocate_node(*(finish.node + j)); throw; } # endif /* __STL_USE_EXCEPTIONS */ } // 释放[before_start.node, start.node)的结点 template <class T, class Alloc, size_t BufSize> void deque<T, Alloc, BufSize>::destroy_nodes_at_front(iterator before_start) { for (map_pointer n = before_start.node; n < start.node; ++n) deallocate_node(*n); } // 释放(finish.node, after_finish.node]的结点 template <class T, class Alloc, size_t BufSize> void deque<T, Alloc, BufSize>::destroy_nodes_at_back(iterator after_finish) { for (map_pointer n = after_finish.node; n > finish.node; --n) deallocate_node(*n); } // 重新配置map, 不会对缓冲区进行操作, map维护的是指向缓冲区的指针 template <class T, class Alloc, size_t BufSize> void deque<T, Alloc, BufSize>::reallocate_map(size_type nodes_to_add, bool add_at_front) { size_type old_num_nodes = finish.node - start.node + 1; size_type new_num_nodes = old_num_nodes + nodes_to_add; map_pointer new_nstart; if (map_size > 2 * new_num_nodes) { new_nstart = map + (map_size - new_num_nodes) / 2 + (add_at_front ? nodes_to_add : 0); if (new_nstart < start.node) copy(start.node, finish.node + 1, new_nstart); else copy_backward(start.node, finish.node + 1, new_nstart + old_num_nodes); } else { size_type new_map_size = map_size + max(map_size, nodes_to_add) + 2; map_pointer new_map = map_allocator::allocate(new_map_size); new_nstart = new_map + (new_map_size - new_num_nodes) / 2 + (add_at_front ? nodes_to_add : 0); copy(start.node, finish.node + 1, new_nstart); map_allocator::deallocate(map, map_size); map = new_map; map_size = new_map_size; } start.set_node(new_nstart); finish.set_node(new_nstart + old_num_nodes - 1); } // Nonmember functions. #ifndef __STL_NON_TYPE_TMPL_PARAM_BUG template <class T, class Alloc, size_t BufSiz> bool operator==(const deque<T, Alloc, BufSiz>& x, const deque<T, Alloc, BufSiz>& y) { return x.size() == y.size() && equal(x.begin(), x.end(), y.begin()); } template <class T, class Alloc, size_t BufSiz> bool operator<(const deque<T, Alloc, BufSiz>& x, const deque<T, Alloc, BufSiz>& y) { return lexicographical_compare(x.begin(), x.end(), y.begin(), y.end()); } #endif /* __STL_NON_TYPE_TMPL_PARAM_BUG */ #if defined(__STL_FUNCTION_TMPL_PARTIAL_ORDER) && \ !defined(__STL_NON_TYPE_TMPL_PARAM_BUG) template <class T, class Alloc, size_t BufSiz> inline void swap(deque<T, Alloc, BufSiz>& x, deque<T, Alloc, BufSiz>& y) { x.swap(y); } #endif #if defined(__sgi) && !defined(__GNUC__) && (_MIPS_SIM != _MIPS_SIM_ABI32) #pragma reset woff 1174 #endif __STL_END_NAMESPACE #endif /* __SGI_STL_INTERNAL_DEQUE_H */ // Local Variables: // mode:C++ // End:
posted on 2015-11-23 11:22 zyz913614263 阅读(477) 评论(0) 编辑 收藏 举报
