mirror of https://github.com/CGAL/cgal
60 lines
1.6 KiB
C++
60 lines
1.6 KiB
C++
// Copyright (c) 2001-2004 ENS of Paris (France).
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// All rights reserved.
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//
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// This file is part of CGAL (www.cgal.org); you may redistribute it under
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// the terms of the Q Public License version 1.0.
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// See the file LICENSE.QPL distributed with CGAL.
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//
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// Licensees holding a valid commercial license may use this file in
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// accordance with the commercial license agreement provided with the software.
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//
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// This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
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// WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
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//
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// $URL$
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// $Id$
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//
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//
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// Author(s) : Pierre Angelier, Michel Pocchiola
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#ifndef CGAL_SIGN_UTILS_H
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#define CGAL_SIGN_UTILS_H
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#include <utility>
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#include <CGAL/basic.h>
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CGAL_BEGIN_NAMESPACE
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Sign
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operator *(Sign s, Sign t)
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{
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if ((s == POSITIVE && t == POSITIVE) ||
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(s == NEGATIVE && t == NEGATIVE)) return POSITIVE;
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else if ((s == POSITIVE && t == NEGATIVE) ||
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(s == NEGATIVE && t == POSITIVE)) return NEGATIVE;
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return ZERO;
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}
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// is s and t have the same sign (or one or both are ZERO) the first element of
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// the pair is true and the sign is the sign of the sum.
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// Otherwise the first element of the pair if false and the second is the sign
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// of s.
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std::pair<bool,Sign>
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sign_of_sum(Sign s, Sign t)
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{
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typedef std::pair<bool,Sign> p;
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if (s == POSITIVE) {
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if (t == POSITIVE || t == ZERO) return p(true,POSITIVE);
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else return p(false,POSITIVE);
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}
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else if (s == NEGATIVE) {
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if (t == NEGATIVE || t == ZERO) return p(true,NEGATIVE);
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else return p(false,NEGATIVE);
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}
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return p(true,t);
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}
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CGAL_END_NAMESPACE
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#endif // SIGN_UTILS_H
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