deque C++实现

模仿源代码。对deque进行了实现。

deque是vector和list的折中。与其说deque是stl中的一个组件不如说是一种设计思想。代码例如以下，虽凝视较少但简单易懂。

/*copyright(c):2014-2020.written by zx 2014.5  
*/

#include<iostream>
#include<algorithm>
#include<type_traits>
using namespace std;

/*buffer size set*/
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));
}

/*一些空间配置器里面的函数*/
struct __false_type{};
struct __true_type{};  
struct input_iterator_tag {};

template<class T,class Ref,class Ptr,size_t BufSiz>

class Deque_iterator{
public:
	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));}
	//5个主要的迭代器型别
	typedef random_access_iterator_tag iterator_category; 
    typedef T value_type;  
    typedef T* pointer;  
    typedef T& reference;  
    typedef size_t size_type;  
    typedef ptrdiff_t difference_type; 
	typedef T** map_pointer;

	typedef Deque_iterator self;
	T* cur; //訪问缓冲区
	T* first ; //指向缓冲区头
	T* last; // 指向缓冲区尾
	map_pointer node; //map中控器
	Deque_iterator():first(0),cur(0),last(0),node(0){}
	Deque_iterator(T* x,map_pointer y):cur(x),first(*y),last(*y+buff_size()),node(y){}
	Deque_iterator(const Deque_iterator& x ):
	cur(x.cur),first(x.first),last(x.last),node(x.node){}	
	void set_node(map_pointer new_node){
		node = new_node;
		first = *new_node;
		last = first + difference_type(buffer_size());
	}
	reference operator*()const{return *cur;}
	pointer operator->()const{return &(operator*());}
	difference_type operator -(const self& x)const{ //量迭代器之间的距离
		return difference_type(buffer_size())*(node-x.node-1)+(cur-first)+(x.last-x.cur);
	}
	self& operator++(){
		++cur;
		if(cur == last){
			set_node(node+1); //切换至下一节点
			cur = first;
		}
		return *this;
	}
	self operator++(int){
		self tmp = *this;
		++*this;
		return tmp;
	}
	self& operator--(){
		if(cur==first){
			set_node(node -1);
			cur = last;
		}
		--cur;
		return *this;
	}
	self operator--(int){
		self tmp = *this;
		--*this;
		return tmp;
	}
	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){
		self tmp = *this;
		return tmp+= n ;
	}
	self& operator-=(difference_type n){return *this+= -n ;}
	self operator-(difference_type n)const{
		self tmp = *this;
		return tmp+= -n;
	}
	bool operator==(const self& x)const{return (cur == x.cur);}
	bool operator!=(const self& x)const{return (cur != x.cur);}
	bool operator<(const self& x)const{//同一个节点或者不同节点
		return node == x.node?(cur<x.cur):(node<x.node);
	}
	reference operator[](difference_type n) const { return *(*this + n); }
};

template<class T,size_t BufSize = 0>
class Deque{
public:
	typedef T value_type;
	typedef value_type* pointer;
	typedef value_type& reference;
	typedef size_t size_type;
	typedef ptrdiff_t difference_type;
public:
	typedef Deque_iterator<T,T&,T*,BufSize> iterator;
protected:
	typedef pointer* map_pointer; // 中控器
	static size_type buffer_size(){
		return _deque_buf_size(BufSize,sizeof(value_type));
	}
	static size_type initial_map_size() { return 8; }  
protected:
	iterator start;
	iterator finish;
	map_pointer map;
	size_type map_size; // map容量
private:
	inline void destroy(iterator first1, iterator last1)  
	{  
		__destroy(first1, last1, pointer(0));  
	}
	inline void __destroy(iterator first, iterator last, T*)  
	{  
		//typedef typename __type_traits<T>::has_trivial_destructor trivial_destructor;  
		//__destroy_aux(first, last, __false_type);  
		__destroy_aux(first, last); 
	}  
	inline void  __destroy_aux(iterator first, iterator last)  
	{  
		for ( ; first < last; ++first)  
			destroy(&*first);  
	}  
	inline void destroy(pointer first,pointer last){
		for(;first<last;++first)
			destroy(first);
	}
	inline void destroy(T* pointer)  
	{  
		pointer->~T();  
	}
public:
	iterator begin(){return start;}
	iterator end(){return  finish;}
	reference operator[](size_type n) { return start[difference_type(n)]; }  
    reference front() { return *start; }  
    reference back()  
    {  
        iterator tmp = finish;  
        --tmp;  
        return *tmp;  
    } 
	size_type size() const { return finish - start; }  
    size_type max_size() const { return size_type(-1); } 
	bool empty() const { return finish == start; }  
private:
	void construct(pointer p, const value_type& value) {new (p) value_type(value);}
	void push_back_aux(const value_type& t){
		value_type t_copy = t;
		reserve_map_at_back();
		*(finish.node + 1) = allocate_node(buffer_size());
		try{
			construct(finish.cur, t_copy);
			finish.set_node(finish.node + 1);
			finish.cur = finish.first;
		}
		catch(...){
			deallocate_node(*(finish.node + 1));
			cout<<"node add failed."<<endl;
			throw;
		}
		
	}
	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 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;
		try {
			for (i = 1; i <= new_nodes; ++i)
			 *(start.node - i) = allocate_node(buffer_size());
		}
		catch(...) {
			for (size_type j = 1; j < i; ++j)
			deallocate_node(*(start.node - j));      
			throw;
		}
	}
	void 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;
		try {
			for (i = 1; i <= new_nodes; ++i)
				*(finish.node + i) = allocate_node(buffer_size());
		}
		catch(...) {
			for (size_type j = 1; j < i; ++j)
			deallocate_node(*(finish.node + j));      
			throw;
		}
	}
	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 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 = allocate_map(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);
			deallocate_map(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);
	}
	void push_front_aux(const value_type& t){
		value_type t_copy = t;
		reserve_map_at_front();
		*(start.node - 1) = allocate_node(buffer_size());
		try {
			start.set_node(start.node - 1);
			start.cur = start.last - 1;
			construct(start.cur, t_copy);
		}
		catch(...) {
			start.set_node(start.node + 1);
			start.cur = start.first;
			deallocate_node(*(start.node - 1));
			throw;
		}
	}
	void  pop_back_aux() {
		deallocate_node(finish.first);
		finish.set_node(finish.node - 1);
		finish.cur = finish.last - 1;
		destroy(finish.cur);
	}
	void pop_front_aux() {
		destroy(start.cur);
		deallocate_node(start.first);
		start.set_node(start.node + 1);
		start.cur = start.first;
	}
	iterator insert_aux(iterator pos, const value_type& x) { //随机插入须要移动数据，效率非常低
		difference_type index = pos - start;
		value_type x_copy = x;
		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;
	}
	void 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;
			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);
				}

			}
			catch(...){
				destroy_nodes_at_front(new_start);
				throw;
			}
		}
		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;
			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);
				}
			}
			catch(...){
				destroy_nodes_at_back(new_finish);
				throw;
			}
		}
	}
	iterator __uninitialized_fill_copy(iterator result, iterator mid,
							const value_type& x,
                           iterator first, iterator last) {
		uninitialized_fill(result, mid, x);
		try {
			return uninitialized_copy(first, last, mid);
		}
		catch(...){
			destroy(result, mid);
			throw;
		}
	}
	void __uninitialized_copy_fill(iterator first1, iterator last1,
                           iterator first2, iterator last2,
                           const value_type& x) {
		iterator mid2 = uninitialized_copy(first1, last1, first2);
		try{
			uninitialized_fill(mid2, last2, x);
		}
		catch(...){
			destroy(first2, mid2);
			throw;
		}
	}
	void destroy_nodes_at_front(iterator before_start) {
		for (map_pointer n = before_start.node; n < start.node; ++n)
			deallocate_node(*n);
	}
	void destroy_nodes_at_back(iterator after_finish) {
		for (map_pointer n = after_finish.node; n > finish.node; --n)
			deallocate_node(*n);
	}
	void deallocate(pointer p,size_type n){
		::operator delete(p);
	}
	/*template <class InputIterator>
	void insert(iterator pos,InputIterator first, InputIterator last,
                                       input_iterator_tag) {
		copy(first, last, inserter(*this, pos));
	}
	template <class Container, class Iterator>
	inline insert_iterator<Container> inserter(Container& x, Iterator i) {
		typedef typename Container::iterator iter;
		return insert_iterator<Container>(x, iter(i));
	}*/
	void creat_map_and_nodes(size_type num_elements){
		size_type num_nodes = num_elements/buffer_size() + 1;
		//在map的前后各预留一个节点。以备扩充
		map_size = max(initial_map_size(),num_nodes+2);
		map = allocate_map(map_size);
		map_pointer nstart = map + (map_size-num_nodes)/2;
		map_pointer nfinish = nstart + num_nodes - 1;
		map_pointer cur;
		try{
			for(cur=nstart;cur<=nfinish;++cur) //为map中的每一个节点配置缓冲区
				*cur = allocate_node(buffer_size());
		}
		catch(...){ //若不成功，回滚
			for (map_pointer ptr = nstart; ptr < cur; ++ptr)  
				deallocate_node(*ptr);  
			deallocate_map(map,map_size);
			throw;
		}
		start.set_node(nstart);
		finish.set_node(nfinish);
		start.cur = start.first;
		finish.cur = finish.first + num_elements % buffer_size();
	}
	void deallocate_map(map_pointer tmp,size_type n){
		::operator delete(tmp);
	}
	void deallocate_node(pointer tmp){
		::operator delete(tmp);
	}
	inline pointer allocate_node(ptrdiff_t size){
		set_new_handler(0);
		pointer tmp = (pointer)(::operator new((size_t)(size*sizeof(value_type))));
		if(tmp == 0){
			cout<<"out of memory"<<endl;
			exit(1);
		}
		return tmp;
	}
	inline map_pointer allocate_map(ptrdiff_t size){
		set_new_handler(0);
		map_pointer tmp = (map_pointer)(::operator new((size_t)(size*sizeof(pointer))));
		if(tmp == 0){
			cout<<"out of memory"<<endl;
			exit(1);
		}
		return tmp;
	}
	void fill_initialize(size_type n,const value_type& value){
		creat_map_and_nodes(n);
		map_pointer cur;
		try{
			for(cur=start.node;cur<finish.node;++cur)
				uninitialized_fill(*cur,*cur+buffer_size(),value);
			uninitialized_fill(finish.first,finish.cur,value);
		}
		catch(...){
			for(map_pointer p=start.node;p<cur;++p)
				deallocate_node(*p); 
			deallocate_map(map,map_size);
			throw;
		}
	}
	void destroy_map_and_nodes() {
		for (map_pointer curr = start.node; curr <= finish.node; ++curr){
			deallocate_node(*curr);
		}
		deallocate_map(map, map_size);
	}
public:
	Deque():start(),finish(),map(0),map_size(0){creat_map_and_nodes(0);}
	Deque(size_type 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());
	}
	Deque(Deque& x): start(), finish(), map(0), map_size(0)
	{
		creat_map_and_nodes(x.size());
		try{
			uninitialized_copy(x.begin(), x.end(), start);
		}
		catch(...){
			cout<<"copy failed."<<endl;
			destroy_map_and_nodes();
			throw;
		}
		
	}
	~Deque(){
		destroy(start,finish);
		destroy_map_and_nodes();
	}
	void push_back(const value_type& t){
		if(finish.cur != finish.last-1){
			construct(finish.cur,t);
			++finish.cur;
		}
		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();
	}
	iterator insert(iterator position, const value_type& x) {
		if (position.cur == start.cur) { //头部插入
			push_front(x);
			return start;
		}
		else if (position.cur == finish.cur) { //尾部插入
			push_back(x);
			iterator tmp = finish;
			--tmp;
			return tmp;
		}
		else {
			return insert_aux(position, x);
		}
	}
	void  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);
	}
	void insert(iterator pos, iterator first, iterator last) {
		//insert(pos, first, last, iterator_category(first));
		iterator tmp = pos; //这样易于实现，可是效率极低
		while(first!=last){
			insert(tmp,(*first));
			++first;
			++tmp;
		}
	}
	iterator erase(iterator pos) { //将要删除的对象移动到队首或者队尾。然后pop
		iterator next = pos;
		++next;
		difference_type index = pos - start;
		if (index < (size() >> 1)) {
			copy_backward(start, pos, next);
			pop_front();
		}
		else {
			copy(next, finish, pos);
			pop_back();
		}
		return start + index;
	}
	iterator 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)
					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)
					deallocate(*cur, buffer_size());
				finish = new_finish;
			}
			return start + elems_before;
		}
	}
	void clear() {
		for (map_pointer node = start.node + 1; node < finish.node; ++node) {
			destroy(*node, *node + buffer_size());
			deallocate(*node, buffer_size());
		}
		if (start.node != finish.node) {
			destroy(start.cur, start.last);
			destroy(finish.first, finish.cur);
			deallocate(finish.first, buffer_size());
		}
		else
			destroy(start.cur, finish.cur);
 
		finish = start;
	}
}; 


void test1(){ // 存储数据类型測试
	Deque<int> dequeInt1;
	Deque<int> dequeInt2(10);
	Deque<int> dequeInt3(10,9);
	for(Deque<int>::iterator iteInt=dequeInt3.begin();iteInt!=dequeInt3.end();++iteInt)
		cout<<*iteInt<<" ";
	cout<<endl;
	Deque<int> dequeInt4(dequeInt3);
	for(Deque<int>::iterator iteInt=dequeInt4.begin();iteInt!=dequeInt4.end();++iteInt)
		cout<<*iteInt<<" ";
	cout<<endl;

	Deque<double> dequeDou1;
	Deque<double> dequeDou2(10);
	Deque<double> dequeDou3(10,2.3);
	for(Deque<double>::iterator iteDou=dequeDou3.begin();iteDou!=dequeDou3.end();++iteDou)
		cout<<*iteDou<<" ";
	cout<<endl;
	Deque<double> dequeDou4(dequeDou3);
	for(Deque<double>::iterator iteDou=dequeDou4.begin();iteDou!=dequeDou4.end();++iteDou)
		cout<<*iteDou<<" ";
	cout<<endl;

	class A{
		int data;
	public:
		A(int a=0):data(a){}
		operator int(){
			return data;
		}
	};
	A a(7);
	Deque<A> dequeA1;
	Deque<A> dequeA2(10);
	Deque<A> dequeA3(10,a);
	for(Deque<A>::iterator iteA=dequeA3.begin();iteA!=dequeA3.end();++iteA)
		cout<<*iteA<<" ";
	cout<<endl;
	Deque<A> dequeA4(dequeA3);
	for(Deque<A>::iterator iteA=dequeA4.begin();iteA!=dequeA4.end();++iteA)
		cout<<*iteA<<" ";
	cout<<endl;
}

void test2(){ //部分功能測试
	Deque<int> dequeInt(10,9);
	for(Deque<int>::iterator iteInt=dequeInt.begin();iteInt!=dequeInt.end();++iteInt)
		cout<<*iteInt<<" ";
	cout<<endl;
	dequeInt.push_back(10);
	for(Deque<int>::iterator iteInt=dequeInt.begin();iteInt!=dequeInt.end();++iteInt)
		cout<<*iteInt<<" ";
	cout<<endl;
	dequeInt.push_front(10);
	for(Deque<int>::iterator iteInt=dequeInt.begin();iteInt!=dequeInt.end();++iteInt)
		cout<<*iteInt<<" ";
	cout<<endl;
	dequeInt.pop_back();
	dequeInt.pop_front();
	for(Deque<int>::iterator iteInt=dequeInt.begin();iteInt!=dequeInt.end();++iteInt)
		cout<<*iteInt<<" ";
	cout<<endl;
	dequeInt.insert(--dequeInt.end(),12);
	for(Deque<int>::iterator iteInt=dequeInt.begin();iteInt!=dequeInt.end();++iteInt)
		cout<<*iteInt<<" ";
	cout<<endl;
	dequeInt.insert(--dequeInt.end(),3,11);
	for(Deque<int>::iterator iteInt=dequeInt.begin();iteInt!=dequeInt.end();++iteInt)
		cout<<*iteInt<<" ";
	cout<<endl;
	Deque<int> dequeInt1(10,0);
	Deque<int>::iterator tmp = dequeInt.end();
	dequeInt.insert(----tmp,dequeInt1.begin(),dequeInt1.end());
	for(Deque<int>::iterator iteInt=dequeInt.begin();iteInt!=dequeInt.end();++iteInt)
		cout<<*iteInt<<" ";
	cout<<endl;
}

void test3(){ //擦除測试
	Deque<int> dequeInt(10,9);
	Deque<int>::iterator iteInt;
	for(iteInt=dequeInt.begin();iteInt!=dequeInt.end();++iteInt)
		cout<<*iteInt<<" ";
	cout<<endl;
	dequeInt.erase(--iteInt);
	for(iteInt=dequeInt.begin();iteInt!=dequeInt.end();++iteInt)
		cout<<*iteInt<<" ";
	cout<<endl;
	Deque<int>::iterator iteInt1 = dequeInt.begin();
	Deque<int>::iterator iteInt2 = dequeInt.end();
	dequeInt.erase(++iteInt1,--iteInt2);
	for(iteInt=dequeInt.begin();iteInt!=dequeInt.end();++iteInt)
		cout<<*iteInt<<" ";
	cout<<endl;
	dequeInt.erase(dequeInt.begin(),dequeInt.end());
	for(iteInt=dequeInt.begin();iteInt!=dequeInt.end();++iteInt)
		cout<<*iteInt<<" ";
	cout<<endl;
}


int main(){
	cout<<"---------data type test-------------"<<endl;
	test1();
	cout<<"---------function  test-------------"<<endl;
	test2();
	cout<<"---------- erase  test--------------"<<endl;
	test3();
}