#include "List.H"

List::List() 
	: _n(0), _size(10), _current(0) 
{
	_list = new int [_size];
}

List::~List() 
{
	if (_list != NULL) 
		delete [] _list;

	_current = -1;
	_size = _n = 0;
}

List::List(const List & rhs) 
	: _n(rhs._n), _size(rhs._size), _current(rhs._current) 
{
	_list = new int [_size];
	for (int i=0; i<_n; i++) 
		_list[i] = rhs._list[i];
}

List & 
List::operator =(const List &rhs) 
{
	_n = rhs._n;
	_size = rhs._size;
	_current = rhs._current;

	_list = new int [_size];
        for (int i=0; i<_n; i++) 
                _list[i] = rhs._list[i];

	return *this;
}

bool 
List::insert(int x) {
	//  Since current is the position for 
	//  the next insertion, it pays to know 
	//  a little about it.
	if (_current < 0) 
		return false;	

	if (_current > _n)
		return false;

	//  If we're out of space for new elements, 
	//  allocate some more...
	if (_n == _size) {
		int * tmp = _list;
		_list = new int [2*_size + 1];
		for (int i=0; i<_n; i++)
			_list[i] = tmp[i];
		delete [] tmp;
		_size = 2*_size+1;
	}

	
	for (int i=_n-1; i>=_current; i--) {
		_list[i+1] = _list[i];
	}
	_list[_current] = x;	
	_n++;

	return true;
}

void 
List::remove() 
{
	if (_current < 0 || _current >= _n)
		return;

	for (int i=_current; i<_n; i++)
		_list[i] = _list[i+1];
	_n--;
}
	
void 
List::next() 
{
	if (_current >= _n) 
		_current = _n;
	else 
		_current++;
}

void 
List::previous() 
{
	if (_current <= 0)
		_current = -1;	
	else
		_current--;
}
	
int  
List::current() 
{
	if (_current < 0 || _current >= _n) 
		cerr << "Uh oh." << endl;
	
	return _list[_current];
}

void 
List::reset() 
{
	_current = 0;
}

bool
List::isEmpty()
{
	return _n == 0;
}

bool 
List::isPastEnd() 
{
	return _current >= _n;
}

ostream &
operator <<(ostream & os, List & l) 
{
	int old_current = l._current;

	if (l.isEmpty())
		return os << "()";

	os << "(";

	bool first_pass=true;
	for (l.reset() ; !l.isPastEnd(); l.next()) {
		if (first_pass) {
			os << l.current();
			first_pass = false;
		} else
			os << "," << l.current();
	}

	l._current = old_current;
	os << ")";
	
	return os;
}