/* This file is part of Raul.
 * Copyright (C) 2007-2009 David Robillard <http://drobilla.net>
 *
 * Raul is free software; you can redistribute it and/or modify it under the
 * terms of the GNU General Public License as published by the Free Software
 * Foundation; either version 2 of the License, or (at your option) any later
 * version.
 *
 * Raul is distributed in the hope that it will be useful, but WITHOUT ANY
 * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
 * FOR A PARTICULAR PURPOSE.  See the GNU General Public License for details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
 */

#ifndef RAUL_LIST_IMPL_HPP
#define RAUL_LIST_IMPL_HPP

namespace Raul {


template <typename T>
List<T>::~List<T>()
{
	clear();
}


/** Clear the list, deleting all Nodes contained (but NOT their contents!)
 *
 * Not realtime safe.
 */
template <typename T>
void
List<T>::clear()
{
	Node* node = _head.get();
	Node* next = NULL;

	while (node) {
		next = node->next();
		delete node;
		node = next;
	}

	_head = 0;
	_tail = 0;
	_size = 0;
}


/** Add an element to the list.
 *
 * Thread safe (may be called while another thread is reading the list).
 * Realtime safe.
 */
template <typename T>
void
List<T>::push_back(Node* const ln)
{
	assert(ln);

	ln->next(NULL);

	if ( ! _head.get()) { // empty
		ln->prev(NULL);
		_tail = ln;
		_head = ln;
	} else {
		ln->prev(_tail.get());
		_tail.get()->next(ln);
		_tail = ln;
	}
	++_size;
}


/** Add an element to the list.
 *
 * Thread safe (may be called while another thread is reading the list).
 * NOT realtime safe (a Node is allocated).
 */
template <typename T>
void
List<T>::push_back(T& elem)
{
	Node* const ln = new Node(elem);

	assert(ln);

	ln->next(NULL);

	if ( ! _head.get()) { // empty
		ln->prev(NULL);
		_tail = ln;
		_head = ln;
	} else {
		ln->prev(_tail.get());
		_tail.get()->next(ln);
		_tail = ln;
	}
	++_size;
}


/** Append a list to this list.
 *
 * This operation is fast ( O(1) ).
 * The appended list is not safe to use concurrently with this call.
 * The appended list will be empty after this call.
 *
 * Thread safe (may be called while another thread is reading the list).
 * Realtime safe.
 */
template <typename T>
void
List<T>::append(List<T>& list)
{
	Node* const my_head    = _head.get();
	Node* const my_tail    = _tail.get();
	Node* const other_head = list._head.get();
	Node* const other_tail = list._tail.get();

	assert((my_head && my_tail) || (!my_head && !my_tail));
	assert((other_head && other_tail) || (!other_head && !other_tail));

	// Appending to an empty list
	if (my_head == NULL && my_tail == NULL) {
		_tail = other_tail;
		_head = other_head;
		_size = list._size;
	} else if (other_head != NULL && other_tail != NULL) {

		other_head->prev(my_tail);

		// FIXME: atomicity an issue? _size < true size is probably fine...
		// no guarantee an iteration runs exactly size times though.  verify/document this.
		// assuming comment above that says tail is writer only, this is fine
		my_tail->next(other_head);
		_tail = other_tail;
		_size += list.size();
	}

	list._head = NULL;
	list._tail = NULL;
	list._size = 0;
}


/** Find an element in the list.
 *
 * This will return the first element equal to @a val found in the list.
 */
template <typename T>
typename List<T>::iterator
List<T>::find(const T& val)
{
	for (iterator i = begin(); i != end(); ++i)
		if (*i == val)
			return i;

	return end();
}


/** Remove an element from the list using an iterator.
 *
 * This function is realtime safe - it is the caller's responsibility to
 * delete the returned Node, or there will be a leak.
 * Thread safe (safe to call while another thread reads the list).
 * @a iter is invalid immediately following this call.
 */
template <typename T>
typename List<T>::Node*
List<T>::erase(const iterator iter)
{
	assert((_head.get() && _tail.get()) || (!_head.get() && !_tail.get()));

	Node* const n = iter._listnode;

	if (n) {
		Node* const prev = n->prev();
		Node* const next = n->next();

		// Removing the head (or the only element)
		if (n == _head.get())
			_head = next;

		// Removing the tail (or the only element)
		if (n == _tail.get())
			_tail = _tail.get()->prev();

		if (prev)
			n->prev()->next(next);

		if (next)
			n->next()->prev(prev);

		--_size;
	}

	assert((_head.get() && _tail.get()) || (!_head.get() && !_tail.get()));
	return n;
}


template <typename T>
void
List<T>::chop_front(List<T>& front, size_t front_size, Node* front_tail)
{
	assert(front_tail);
	assert((front._head.get() && front._tail.get()) || (!front._head.get() && !front._tail.get()));
	assert((_head.get() && _tail.get()) || (!_head.get() && !_tail.get()));
	front._size = front_size;
	front._head = _head;
	front._tail = front_tail;
	Node* new_head = front_tail->next();
	if (new_head) {
		new_head->prev(NULL);
		_head = new_head;
	} else {
		// FIXME: race?
		_head = NULL;
		_tail = NULL;
	}
	_size -= front_size;
	front_tail->next(NULL);
	assert((front._head.get() && front._tail.get()) || (!front._head.get() && !front._tail.get()));
	assert((_head.get() && _tail.get()) || (!_head.get() && !_tail.get()));
}


//// Iterator stuff ////

template <typename T>
List<T>::iterator::iterator(List<T>* list)
: _list(list),
  _listnode(NULL)
{
}


template <typename T>
T&
List<T>::iterator::operator*()
{
	assert(_listnode);
	return _listnode->elem();
}


template <typename T>
T*
List<T>::iterator::operator->()
{
	assert(_listnode);
	return &_listnode->elem();
}


template <typename T>
inline typename List<T>::iterator&
List<T>::iterator::operator++()
{
	assert(_listnode);
	_listnode = _listnode->next();

	return *this;
}


template <typename T>
inline bool
List<T>::iterator::operator!=(const iterator& iter) const
{
	return (_listnode != iter._listnode);
}


template <typename T>
inline bool
List<T>::iterator::operator!=(const const_iterator& iter) const
{
	return (_listnode != iter._listnode);
}


template <typename T>
inline bool
List<T>::iterator::operator==(const iterator& iter) const
{
	return (_listnode == iter._listnode);
}


template <typename T>
inline bool
List<T>::iterator::operator==(const const_iterator& iter) const
{
	return (_listnode == iter._listnode);
}


template <typename T>
inline typename List<T>::iterator
List<T>::begin()
{
	typename List<T>::iterator iter(this);

	iter._listnode = _head.get();

	return iter;
}


template <typename T>
inline const typename List<T>::iterator
List<T>::end() const
{
	return _end_iter;
}



/// const_iterator stuff ///


template <typename T>
List<T>::const_iterator::const_iterator(const List<T>* const list)
: _list(list),
  _listnode(NULL)
{
}


template <typename T>
const T&
List<T>::const_iterator::operator*()
{
	assert(_listnode);
	return _listnode->elem();
}


template <typename T>
const T*
List<T>::const_iterator::operator->()
{
	assert(_listnode);
	return &_listnode->elem();
}


template <typename T>
inline typename List<T>::const_iterator&
List<T>::const_iterator::operator++()
{
	assert(_listnode);
	_listnode = _listnode->next();

	return *this;
}


template <typename T>
inline bool
List<T>::const_iterator::operator!=(const const_iterator& iter) const
{
	return (_listnode != iter._listnode);
}


template <typename T>
inline bool
List<T>::const_iterator::operator!=(const iterator& iter) const
{
	return (_listnode != iter._listnode);
}


template <typename T>
inline bool
List<T>::const_iterator::operator==(const const_iterator& iter) const
{
	return (_listnode == iter._listnode);
}


template <typename T>
inline bool
List<T>::const_iterator::operator==(const iterator& iter) const
{
	return (_listnode == iter._listnode);
}

template <typename T>
inline typename List<T>::const_iterator
List<T>::begin() const
{
	typename List<T>::const_iterator iter(this);
	iter._listnode = _head.get();
	return iter;
}


} // namespace Raul


#endif // RAUL_LIST_IMPL_HPP