#ifndef _SpatialEdge_h
#define _SpatialEdge_h
/*
//#     Filename:       SpatialEdge.h
//#
//#     SpatialEdge is a helper class for the spatial index at construction
//#     time.
//#
//#
//#     Author:         Peter Z. Kunszt, based on A. Szalay's code
//#     
//#     Date:           October 15, 1998
//#
//#
//#
//# (c) Copyright The Johns Hopkins University 1998
//# All Rights Reserved
//#
//# The software and information contained herein are proprietary to The
//# Johns Hopkins University, Copyright 1998.  This software is furnished
//# pursuant to a written license agreement and may be used, copied,
//# transmitted, and stored only in accordance with the terms of such
//# license and with the inclusion of the above copyright notice.  This
//# software and information or any other copies thereof may not be
//# provided or otherwise made available to any other person.
//#
//#
*/
#include "SpatialIndex.h"

/*
//########################################################################
//
// <GROUP>
// <SUMMARY>Class declarations</SUMMARY>
// 

//########################################################################
//
// <SUMMARY> Spatial Edge class </SUMMARY>
//
// The Edges are needed at construction time of the spatial index. 
// They are used to generate the midpoints of the nodes in a certain layer.
// The interface is simple: construct a class giving it the SpatialIndex
// and the layer number. Then call makeMidPoints. The SpatialIndex will
// then have its midpoint constructed in every QuadNode.
*/

typedef struct {
  size_t	start_;		/* starting vertex index of edge */
  size_t	end_;		/* index of end */
  size_t 	mid_;		/* index of center */
} Edge;

typedef struct {
  SpatialIndex *	tree_;		/* reference to the tree class */
  size_t		layerindex_;	/* index of the layer */
  Edge ** 		lTab_;		/* Edges lookup table */
  Edge *  		edges_;		/* Edges array */
  size_t		index_;		/* index of the vertex that is built */
} SpatialEdge;

/* Constructor : give the tree and its layer */
SpatialEdge * spatialEdgeNew(SpatialIndex * tree, size_t layerindex );

/* Destructor */
void spatialEdgeDelete( SpatialEdge * );

/* Interface to class: generate midpoints. */
void spatialEdgeMakeMidPoints( SpatialEdge * );

/* Make a new edge, in the temporary edges_ at emindex, at node_[index]
 * using the k'th side. Since every edge belongs to two faces, we have]
 * to check wether an edge has been already processed or not (i.e. the
 * midpoint has been constructed or not). We have a lookup table for
 * this purpose. Every edge is stored at lTab[start_]. There may be
 * up to 6 edges in every vertex[start_] so if that table place is occupied,
 * store it in the next table position (and so on). So we only have to
 * look up 6 positions at most.
 */
size_t spatialEdgeNewEdge( SpatialEdge *, size_t emindex, size_t index, int k);

/* insert the edge em into the lookup table */
void spatialEdgeInsertLookup( SpatialEdge *, Edge *em );

/* lookup the edge em in the lookup table */
Edge * spatialEdgeEdgeMatch( SpatialEdge *, Edge *em );

/* generate a new vertex, which is the midpoint of the current edge. */
size_t spatialEdgeGetMidPoint( SpatialEdge *, Edge * em );

#endif