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list.h
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list.h
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#ifndef LIST_H
#define LIST_H
#include "generic.h"
namespace algo {
template <typename Object>
class List {
private:
class ListNode {
public:
ListNode( const Object & obj = Object{ },
ListNode *pNext = nullptr,
ListNode *pPrev = nullptr )
: element{ obj }, next { pNext }, prev { pPrev } { }
ListNode( const Object && obj,
ListNode *pNext = nullptr,
ListNode *pPrev = nullptr )
: element( std::move( obj ) ), next ( pNext ), prev ( pPrev ) { }
private:
Object element;
ListNode* next;
ListNode* prev;
friend class List<Object>;
}; //end of class ListNode
public:
class const_iterator {
public:
const_iterator( ) : current{ nullptr }
{ }
const Object& operator* ( ) const
{
return retrieve( );
}
const_iterator& operator++ ( )
{
current = current->next;
return *this;
}
const_iterator operator++ ( int )
{
const_iterator old = *this;
++ ( *this );
return old;
}
const_iterator & operator-- ( )
{
current = current->prev;
return *this;
}
const_iterator operator-- ( int )
{
const_iterator old = *this;
--( *this );
return old;
}
bool operator== ( const const_iterator& rhs ) const
{
return ( current == rhs.current );
}
bool operator!= ( const const_iterator& rhs ) const
{
return ( current != rhs.current );
}
protected:
ListNode *current;
Object& retrieve ( ) const
{
return current->element;
}
const_iterator( ListNode *p )
: current{ p } { }
friend class List<Object>;
}; //end of class const_iterator
class iterator : public const_iterator {
public:
iterator( ) { }
Object & operator*( )
{
return const_iterator::retrieve( );
}
const Object & operator*( ) const
{
return const_iterator::operator*( );
}
iterator & operator++( )
{
this->current = this->current->next;
return *this;
}
iterator operator++ ( int )
{
iterator old = *this;
++ ( *this );
return old;
}
iterator & operator--( )
{
this->current = this->current->prev;
return *this;
}
iterator operator-- ( int )
{
iterator old = *this;
-- ( *this );
return old;
}
protected:
iterator( ListNode* node ) : const_iterator { node }
{ }
friend class List<Object>;
}; //end of class iterator
public:
List( )
{
initialize( );
}
~List( )
{
clear( );
delete _head;
delete _tail;
}
List( const List& rhs )
{
initialize( );
for (auto & elem : rhs ) {
push_back( elem );
}
}
List ( List && rhs )
: _size( rhs._size ), _head( rhs._head ), _tail( rhs._tail )
{
rhs._size = 0;
rhs._head = rhs._tail = nullptr;
}
List& operator= ( const List & rhs )
{
List copy = rhs;
algo::swap( copy, *this );
return *this;
}
List& operator= ( List && rhs )
{
algo::swap( _size, rhs._size );
algo::swap( _head, rhs._head );
algo::swap( _tail, rhs._tail );
return *this;
}
iterator begin( )
{
return iterator( _head->next );
}
const_iterator begin( ) const
{
return const_iterator( _head->next );
}
iterator end( )
{
return iterator( _tail );
}
const_iterator end( ) const
{
return const_iterator( _tail );
}
int size( ) const
{
return _size;
}
bool empty( ) const
{
return ( _size == 0 );
}
void clear( )
{
while ( !empty( ) )
pop_front( );
}
Object& front( )
{
return (*begin( ) );
}
const Object& front( ) const
{
return (*begin( ) );
}
Object& back( )
{
return (*--end( ) );
}
const Object& back( ) const
{
return (*--end( ) );
}
void push_front( const Object& obj )
{
insert( obj, begin( ) );
}
void push_front( Object && obj )
{
insert( std::move( obj ), begin( ) );
}
void push_back( const Object & obj )
{
insert( obj, end( ) );
}
void push_back ( Object && obj )
{
insert( std::move( obj ), end( ) );
}
void pop_front( )
{
erase( begin( ) );
}
void pop_back( )
{
erase( --end( ) );
}
iterator insert( const Object & obj, iterator it )
{
ListNode *currNode = it.current;
ListNode *newNode = new ListNode{ obj, currNode, currNode->prev };
currNode->prev->next = newNode;
currNode->prev = newNode;
++_size;
return iterator( newNode );
}
iterator erase( iterator it )
{
ListNode* currNode = it.current;
iterator returnItr( currNode->next );
currNode->prev->next = currNode->next;
currNode->next->prev = currNode->prev;
delete currNode;
--_size;
return returnItr;
}
iterator erase( iterator from, iterator to )
{
for( iterator it = from; it != to; ) {
it = erase( it );
}
return to;
}
private:
int _size;
ListNode *_head;
ListNode *_tail;
void initialize( )
{
_size = 0;
_head = new ListNode;
_tail = new ListNode;
_head->next = _tail;
_tail->prev = _head;
}
}; //end of class List
} //end of namespace algo
#endif