128 lines
3.7 KiB
C++
128 lines
3.7 KiB
C++
// Copyright (c) 2006-2008 Fernando Luis Cacciola Carballal. All rights reserved.
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//
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// This file is part of CGAL (www.cgal.org)
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//
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// $URL: https://github.com/CGAL/cgal/blob/v5.1/Straight_skeleton_2/include/CGAL/certified_quotient_predicates.h $
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// $Id: certified_quotient_predicates.h 0779373 2020-03-26T13:31:46+01:00 Sébastien Loriot
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// SPDX-License-Identifier: LGPL-3.0-or-later OR LicenseRef-Commercial
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//
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// Author(s) : Fernando Cacciola <fernando_cacciola@ciudad.com.ar>
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//
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#ifndef CGAL_CERTIFIED_QUOTIENT_PREDICATES_H
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#define CGAL_CERTIFIED_QUOTIENT_PREDICATES_H
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#include <CGAL/certified_numeric_predicates.h>
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#include <CGAL/Quotient.h>
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namespace CGAL {
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template <class NT>
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inline Uncertain<bool> certified_quotient_is_positive(const Quotient<NT>& x)
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{
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Uncertain<Sign> signum = CGAL_NTS certified_sign(x.num) ;
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Uncertain<Sign> sigden = CGAL_NTS certified_sign(x.den) ;
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Uncertain<Sign> zero(ZERO);
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return ( signum != zero ) & ( signum == sigden );
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}
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template <class NT>
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inline Uncertain<bool> certified_quotient_is_negative(const Quotient<NT>& x)
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{
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Uncertain<Sign> signum = CGAL_NTS certified_sign(x.num) ;
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Uncertain<Sign> sigden = CGAL_NTS certified_sign(x.den) ;
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Uncertain<Sign> zero(ZERO);
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return ( signum != zero ) & ( signum != sigden );
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}
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template <class NT>
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inline Uncertain<bool> certified_quotient_is_zero(const Quotient<NT>& x)
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{
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return CGAL_NTS certified_is_zero(x.num) ;
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}
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template <class NT>
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CGAL_MEDIUM_INLINE
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Uncertain<Sign> certified_quotient_sign(const Quotient<NT>& x)
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{
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// No assumptions on the sign of den are made
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return CGAL_NTS certified_sign(x.num) * CGAL_NTS certified_sign(x.den);
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}
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template <class NT1, class NT2>
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CGAL_MEDIUM_INLINE
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Uncertain<Comparison_result> certified_quotient_compare(const Quotient<NT1>& x, const Quotient<NT2>& y)
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{
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Uncertain<Comparison_result> r = Uncertain<Comparison_result>::indeterminate();
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// No assumptions on the sign of den are made
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// code assumes that SMALLER == - 1;
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CGAL_precondition( SMALLER == static_cast<Comparison_result>(-1) );
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Uncertain<Sign> xnumsign = CGAL_NTS certified_sign(x.num) ;
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Uncertain<Sign> xdensign = CGAL_NTS certified_sign(x.den) ;
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Uncertain<Sign> ynumsign = CGAL_NTS certified_sign(y.num) ;
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Uncertain<Sign> ydensign = CGAL_NTS certified_sign(y.den) ;
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if ( is_certain(xnumsign)
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&& is_certain(xdensign)
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&& is_certain(ynumsign)
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&& is_certain(ydensign)
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)
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{
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int xsign = xnumsign * xdensign ;
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int ysign = ynumsign * ydensign ;
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if (xsign == 0) return static_cast<Comparison_result>(-ysign);
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if (ysign == 0) return static_cast<Comparison_result>(xsign);
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// now (x != 0) && (y != 0)
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int diff = xsign - ysign;
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if (diff == 0)
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{
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int msign = xdensign * ydensign;
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NT1 leftop = x.num * y.den * msign;
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NT1 rightop = y.num * x.den * msign;
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r = certified_compare(leftop, rightop);
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}
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else
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{
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r = (xsign < ysign) ? SMALLER : LARGER;
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}
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}
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return r ;
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}
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template <class NT>
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inline Uncertain<bool> certified_is_zero(const Quotient<NT>& n)
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{
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return certified_quotient_is_zero(n);
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}
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template <class NT>
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inline Uncertain<bool> certified_is_positive(const Quotient<NT>& n)
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{
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return certified_quotient_is_positive(n);
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}
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template <class NT>
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inline Uncertain<bool> certified_is_negative(const Quotient<NT>& n)
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{
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return certified_quotient_is_negative(n);
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}
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template <class NT>
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inline Uncertain<Sign> certified_sign(const Quotient<NT>& n)
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{
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return certified_quotient_sign(n);
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}
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template <class NT1, class NT2>
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inline Uncertain<Comparison_result> certified_compare(const Quotient<NT1>& n1, const Quotient<NT2>& n2)
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{
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return certified_quotient_compare(n1,n2);
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}
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} // end namespace CGAL
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#endif // CGAL_CERTIFIED_QUOTIENT_PREDICATES_H
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