//
// Copyright (C) 2004 Tanguy Fautré.
// For conditions of distribution and use,
// see copyright notice in tri_stripper.h
//
//////////////////////////////////////////////////////////////////////
// SVN: $Id: graph_array.h 93 2009-11-24 20:01:19Z gpsnoopy $
//////////////////////////////////////////////////////////////////////

#ifndef TRI_STRIPPER_HEADER_GUARD_GRAPH_ARRAY_H
#define TRI_STRIPPER_HEADER_GUARD_GRAPH_ARRAY_H

#include <cassert>
#include <algorithm>
#include <functional>
#include <limits>
#include <vector>




namespace triangle_stripper {

	namespace detail {




// graph_array main class
template <class nodetype>
class graph_array 
{
public:

	class arc;
	class node;

	// New types
	typedef size_t											nodeid;
	typedef nodetype										value_type;
	typedef std::vector<node>								node_vector;
	typedef typename node_vector::iterator					node_iterator;
	typedef typename node_vector::const_iterator			const_node_iterator;
	typedef typename node_vector::reverse_iterator			node_reverse_iterator;
	typedef typename node_vector::const_reverse_iterator	const_node_reverse_iterator;

	typedef graph_array<nodetype> graph_type;
	

	// graph_array::arc class
	class arc
	{
	public:
		node_iterator terminal() const;

	protected:
		friend class graph_array<nodetype>;

		arc(node_iterator Terminal);
	
		node_iterator	m_Terminal;
	};


	// New types
	typedef std::vector<arc>					arc_list;
	typedef typename arc_list::iterator			out_arc_iterator;
	typedef typename arc_list::const_iterator	const_out_arc_iterator;


	// graph_array::node class
	class node
	{
	public:
		void mark();
		void unmark();
		bool marked() const;

		bool out_empty() const;
		size_t out_size() const;

		out_arc_iterator out_begin();
		out_arc_iterator out_end();
		const_out_arc_iterator out_begin() const;
		const_out_arc_iterator out_end() const;

		value_type & operator * ();
		value_type * operator -> ();
		const value_type & operator * () const;
		const value_type * operator -> () const;

		value_type & operator = (const value_type & Elem);

	protected:
		friend class graph_array<nodetype>;
		friend class std::vector<node>;

		node(arc_list & Arcs);

		arc_list &		m_Arcs;
		size_t			m_Begin;
		size_t			m_End;

		value_type		m_Elem;
		bool			m_Marker;
	};


	graph_array();
	explicit graph_array(size_t NbNodes);

	// Node related member functions
	bool empty() const;
	size_t size() const;

	node & operator [] (nodeid i);
	const node & operator [] (nodeid i) const;

	node_iterator begin();
	node_iterator end();
	const_node_iterator begin() const;
	const_node_iterator end() const;

	node_reverse_iterator rbegin();
	node_reverse_iterator rend();
	const_node_reverse_iterator rbegin() const;
	const_node_reverse_iterator rend() const;

	// Arc related member functions
	out_arc_iterator insert_arc(nodeid Initial, nodeid Terminal);
	out_arc_iterator insert_arc(node_iterator Initial, node_iterator Terminal);

	// Optimized (overloaded) functions
	void swap(graph_type & Right);
	friend void swap(graph_type & Left, graph_type & Right)										{ Left.swap(Right); }

protected:
	graph_array(const graph_type &);
	graph_type & operator = (const graph_type &);

	node_vector		m_Nodes;
	arc_list		m_Arcs;
};



// Additional "low level", graph related, functions
template <class nodetype>
void unmark_nodes(graph_array<nodetype> & G);





//////////////////////////////////////////////////////////////////////////
// graph_array::arc inline functions
//////////////////////////////////////////////////////////////////////////

template <class N>
inline graph_array<N>::arc::arc(node_iterator Terminal)
	: m_Terminal(Terminal) { }


template <class N>
inline typename graph_array<N>::node_iterator graph_array<N>::arc::terminal() const
{
	return m_Terminal;
}



//////////////////////////////////////////////////////////////////////////
// graph_array::node inline functions
//////////////////////////////////////////////////////////////////////////

template <class N>
inline graph_array<N>::node::node(arc_list & Arcs)
	: m_Arcs(Arcs),
	  m_Begin((std::numeric_limits<size_t>::max)()),
	  m_End((std::numeric_limits<size_t>::max)()),
	  m_Marker(false)
{

}


template <class N>
inline void graph_array<N>::node::mark()
{
	m_Marker = true;
}


template <class N>
inline void graph_array<N>::node::unmark()
{
	m_Marker = false;
}


template <class N>
inline bool graph_array<N>::node::marked() const
{
	return m_Marker;
}


template <class N>
inline bool graph_array<N>::node::out_empty() const
{
	return (m_Begin == m_End);
}


template <class N>
inline size_t graph_array<N>::node::out_size() const
{
	return (m_End - m_Begin);
}


template <class N>
inline typename graph_array<N>::out_arc_iterator graph_array<N>::node::out_begin()
{
	return (m_Arcs.begin() + m_Begin);
}


template <class N>
inline typename graph_array<N>::out_arc_iterator graph_array<N>::node::out_end()
{
	return (m_Arcs.begin() + m_End);
}


template <class N>
inline typename graph_array<N>::const_out_arc_iterator graph_array<N>::node::out_begin() const
{
	return (m_Arcs.begin() + m_Begin);
}


template <class N>
inline typename graph_array<N>::const_out_arc_iterator graph_array<N>::node::out_end() const
{
	return (m_Arcs.begin() + m_End);
}


template <class N>
inline N & graph_array<N>::node::operator * ()
{
	return m_Elem;
}


template <class N>
inline N * graph_array<N>::node::operator -> ()
{
	return &m_Elem;
}


template <class N>
inline const N & graph_array<N>::node::operator * () const
{
	return m_Elem;
}


template <class N>
inline const N * graph_array<N>::node::operator -> () const
{
	return &m_Elem;
}


template <class N>
inline N & graph_array<N>::node::operator = (const N & Elem)
{
	return (m_Elem = Elem);
}



//////////////////////////////////////////////////////////////////////////
// graph_array inline functions
//////////////////////////////////////////////////////////////////////////

template <class N>
inline graph_array<N>::graph_array() { }


template <class N>
inline graph_array<N>::graph_array(const size_t NbNodes)
	: m_Nodes(NbNodes, node(m_Arcs))
{
	// optimisation: we consider that, averagely, a triangle may have at least 2 neighbours
	// otherwise we are just wasting a bit of memory, but not that much
	m_Arcs.reserve(NbNodes * 2);
}


template <class N>
inline bool graph_array<N>::empty() const
{
	return m_Nodes.empty();
}


template <class N>
inline size_t graph_array<N>::size() const 
{
	return m_Nodes.size();
}


template <class N>
inline typename graph_array<N>::node & graph_array<N>::operator [] (const nodeid i)
{
	assert(i < size());

	return m_Nodes[i];
}


template <class N>
inline const typename graph_array<N>::node & graph_array<N>::operator [] (const nodeid i) const
{
	assert(i < size());

	return m_Nodes[i];
}


template <class N>
inline typename graph_array<N>::node_iterator graph_array<N>::begin()
{
	return m_Nodes.begin();
}


template <class N>
inline typename graph_array<N>::node_iterator graph_array<N>::end()
{
	return m_Nodes.end();
}


template <class N>
inline typename graph_array<N>::const_node_iterator graph_array<N>::begin() const
{
	return m_Nodes.begin();
}


template <class N>
inline typename graph_array<N>::const_node_iterator graph_array<N>::end() const
{
	return m_Nodes.end();
}


template <class N>
inline typename graph_array<N>::node_reverse_iterator graph_array<N>::rbegin()
{
	return m_Nodes.rbegin();
}


template <class N>
inline typename graph_array<N>::node_reverse_iterator graph_array<N>::rend()
{
	return m_Nodes.rend();
}


template <class N>
inline typename graph_array<N>::const_node_reverse_iterator graph_array<N>::rbegin() const
{
	return m_Nodes.rbegin();
}


template <class N>
inline typename graph_array<N>::const_node_reverse_iterator graph_array<N>::rend() const
{
	return m_Nodes.rend();
}


template <class N>
inline typename graph_array<N>::out_arc_iterator graph_array<N>::insert_arc(const nodeid Initial, const nodeid Terminal)
{
	assert(Initial < size());
	assert(Terminal < size());

	return insert_arc(m_Nodes.begin() + Initial, m_Nodes.begin() + Terminal);
}


template <class N>
inline typename graph_array<N>::out_arc_iterator graph_array<N>::insert_arc(const node_iterator Initial, const node_iterator Terminal)
{
	assert((Initial >= begin()) && (Initial < end()));
	assert((Terminal >= begin()) && (Terminal < end()));

	node & Node = * Initial;

	if (Node.out_empty()) {

		Node.m_Begin = m_Arcs.size();
		Node.m_End = m_Arcs.size() + 1;

	} else {

		// we optimise here for make_connectivity_graph()
		// we know all the arcs for a given node are successively and sequentially added
		assert(Node.m_End == m_Arcs.size());
		
		++(Node.m_End);
	}

	m_Arcs.push_back(arc(Terminal));

	out_arc_iterator it = m_Arcs.end();
	return (--it);
}


template <class N>
inline void graph_array<N>::swap(graph_type & Right)
{
	std::swap(m_Nodes, Right.m_Nodes);
	std::swap(m_Arcs, Right.m_Arcs);
}



//////////////////////////////////////////////////////////////////////////
// additional functions
//////////////////////////////////////////////////////////////////////////

template <class N>
inline void unmark_nodes(graph_array<N> & G)
{
	std::for_each(G.begin(), G.end(), std::mem_fun_ref(&graph_array<N>::node::unmark));
}




	} // namespace detail

} // namespace triangle_stripper




#endif // TRI_STRIPPER_HEADER_GUARD_GRAPH_ARRAY_H
