// Copyright (c) 2006-2007 Max-Planck-Institute Saarbruecken (Germany).
// All rights reserved.
//
// This file is part of CGAL (www.cgal.org); you can redistribute it and/or
// modify it under the terms of the GNU Lesser General Public License as
// published by the Free Software Foundation; either version 3 of the License,
// or (at your option) any later version.
//
// Licensees holding a valid commercial license may use this file in
// accordance with the commercial license agreement provided with the software.
//
// This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
// WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
//
// $URL$
// $Id$
//
// Author(s)     : Michael Hemmer, Dominik Hülse
//
// ============================================================================

#include <CGAL/basic.h>
#include <CGAL/Arithmetic_kernel.h>
#include <CGAL/Algebraic_structure_traits.h>
#include <cassert>
#include <CGAL/extended_euclidean_algorithm.h>

//#define WITH_OUTPUT 1

template<class Integer>
void test_extended_euclidean_algorithm() {
    Integer a, b, e, u, v;  

    // common factor is 2
    a = Integer(1008);
    b = Integer(4352);
    e = CGAL::extended_euclidean_algorithm(a, b,u ,v );
    assert(Integer(16) == e);
    assert(e == a*u + b*v);


    a = Integer(-1008);
    b = Integer(4352);
    e = CGAL::extended_euclidean_algorithm(a, b,u ,v );
    assert(Integer(16) == e);
    assert(e == a*u + b*v);

    a = Integer(1008);
    b = Integer(-4352);
    e = CGAL::extended_euclidean_algorithm(a, b,u ,v );
    assert(Integer(16) == e);
    assert(e == a*u + b*v);

    a = Integer(-1008);
    b = Integer(-4352);
    e = CGAL::extended_euclidean_algorithm(a, b,u ,v );
    assert(Integer(16) == e);
    assert(e == a*u + b*v);

    a = CGAL::integral_division(a,e);
    b = CGAL::integral_division(b,e);
    e = CGAL::extended_euclidean_algorithm(a, b,u ,v );
    assert(Integer(1) == e);
    assert(e == a*u + b*v);

    // special cases 
    // common factor is 1
    a = Integer(17);
    b = Integer(13);
    e = CGAL::extended_euclidean_algorithm(a, b,u ,v );
    assert(Integer(1) == e);
    assert(e == a*u + b*v);
 
    // one number is 0 
    a = Integer(0);
    b = Integer(13);
    e = CGAL::extended_euclidean_algorithm(a, b,u ,v );
    assert(b == e);
    assert(e == a*u + b*v);

    a = Integer(24);
    b = Integer(0);
    e = CGAL::extended_euclidean_algorithm(a, b,u ,v );
    assert(a == e);
    assert(e == a*u + b*v);

    // both numbers are 0
    a = Integer(0);
    b = Integer(0);
    e = CGAL::extended_euclidean_algorithm(a, b,u ,v );
    assert(b == e);
    assert(e == a*u + b*v);
}

int main(){
    test_extended_euclidean_algorithm<long>();     
    return 0;
}


// EOF