// Description: implementation of sweep status structure function object and utility classes

// Revision history: 5/8/99/LY

	

#include "decl.h"

#include "sweep.h"

	

bool SweepKeyCmp::operator() (const SweepElementKey& sw_lhs, const SweepElementKey& sw_rhs) const

{	

	// if sw_lhs is farther down the screen than sw_rhs

	if (sw_lhs.upper.second > sw_rhs.upper.second)

	{	// find x-coord of sw_rhs at sw_lhs.upper.second

		double x = sw_rhs.upper.first + ((sw_lhs.upper.second - sw_rhs.upper.second)*sw_rhs.slope);

		return sw_lhs.upper.first <= x;

	}

	// if sw_rhs is farther down the screen than sw_lhs

	else if (sw_rhs.upper.second > sw_lhs.upper.second)

	{	// find x-coord of sw_lhs at sw_rhs.upper.second

		double x = sw_lhs.upper.first + ((sw_rhs.upper.second - sw_lhs.upper.second)*sw_lhs.slope);

		return x < sw_rhs.upper.first;

	}

	// if sw_rhs and sw_lhs share the same upper endpoint (y-coordinate equality is implied at this juncture)

	else if (sw_rhs.upper.first == sw_lhs.upper.first)

	{	return sw_lhs.slope < sw_rhs.slope;	}

	// if sw_lhs and sw_rhs share upper endpoint y-coordinate but not x-coordinate

	else return sw_lhs < sw_rhs;

}