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 * 
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 * 
 *   http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 * 
 *************************************************************/



// MARKER(update_precomp.py): autogen include statement, do not remove
#include "precompiled_vcl.hxx"

#include "aqua/salmathutils.hxx"

#include <stdlib.h>

// =======================================================================

// =======================================================================

#define Swap( x, y ) { x ^= y; y ^= x; x ^= y; }

// =======================================================================

// =======================================================================

// Storage free swapping using XOR

void CSwap ( char &rX, char &rY )
{
	Swap( rX, rY );
} // CSwap

// -----------------------------------------------------------------------

// Storage free swapping using XOR

void UCSwap ( unsigned char &rX, unsigned char &rY )
{
	Swap( rX, rY );
} // UCSwap

// -----------------------------------------------------------------------

// Storage free swapping using XOR

void SSwap ( short &rX, short &rY )
{
	Swap( rX, rY );
} // SSwap

// -----------------------------------------------------------------------

// Storage free swapping using XOR

void USSwap ( unsigned short &rX, unsigned short &rY )
{
	Swap( rX, rY );
} // USSwap

// -----------------------------------------------------------------------

// Storage free swapping using XOR

void LSwap ( long &rX, long &rY )
{
	Swap( rX, rY );
} // LSwap

// -----------------------------------------------------------------------

// Storage free swapping using XOR

void ULSwap ( unsigned long &rX, unsigned long &rY )
{
	Swap( rX, rY );
} // ULSwap

// =======================================================================

// =======================================================================

// -----------------------------------------------------------------------
//
// This way of measuring distance is also called the "Manhattan distance."
// Manhattan distance takes advantage of the fact that the sum of the 
// lengths of the three components of a 3D vector is a rough approxima-
// tion of the vector's length.
//
// -----------------------------------------------------------------------

unsigned long  Euclidian2Norm ( const LRectCoorVector  pVec )
{
	unsigned long  ndist = 0;
	
	if ( pVec )
	{
		long           nDX  = 0;
		long           nDY  = 0;
		long           nDZ  = 0;
		unsigned long  nMax = 0;
		unsigned long  nMed = 0;
		unsigned long  nMin = 0;
		
		// Find |x'-x|, |y'-y|, and |z'-z| from (x,y,z) and (x',y',z')
		
		nDX = pVec[1].x - pVec[0].x;
		nDY = pVec[1].y - pVec[0].y;
		nDZ = pVec[1].z - pVec[0].z;
			
		nMax = (unsigned long)abs( nDX );
		nMed = (unsigned long)abs( nDY );
		nMin = (unsigned long)abs( nDZ );
		
		// Sort them (3 compares, 0-3 swaps)
		
		if ( nMax < nMed )
		{
			Swap( nMax, nMed );
		} // if
		
		if ( nMax < nMin )
		{
			Swap( nMax, nMin );
		} // if
		
		// Approximate Euclidian distance:
		//
		//    d = max + (11/32)*med + (1/4)*min
		//
		// with +/- 8% error, where the exact formulae for d is
		//
		//  || (x',y',z') - (x,y,z) || = { |x'-x|^2 + |y'-y|^2 + |z'-z|^2 }^(1/2)
		
		ndist = nMax + ( nMin >> 2UL ) 
		             + ( ( ( nMed << 3UL ) + ( nMed << 1UL ) + nMed ) >> 5UL );
	} // if
		
	return ndist;
} // RGBDistance

// =======================================================================

// =======================================================================