159 lines
4.6 KiB
C++
159 lines
4.6 KiB
C++
// Copyright (c) 2005,2007
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// Utrecht University (The Netherlands),
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// ETH Zurich (Switzerland),
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// INRIA Sophia-Antipolis (France),
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// Max-Planck-Institute Saarbruecken (Germany),
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// and Tel-Aviv University (Israel). 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/Number_types/include/CGAL/long_double.h $
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// $Id: long_double.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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//
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// Author(s) : Sylvain Pion, Michael Hemmer
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#ifndef CGAL_LONG_DOUBLE_H
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#define CGAL_LONG_DOUBLE_H
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#include <utility>
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#include <cmath>
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#ifdef CGAL_CFG_IEEE_754_BUG
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# include <CGAL/IEEE_754_unions.h>
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#endif
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// #include <CGAL/FPU.h>
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#include <CGAL/Interval_nt.h>
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#include <CGAL/assertions.h>
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#include <CGAL/functional.h>
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namespace CGAL {
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// Is_valid moved to top, since used by is_finite
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#ifdef CGAL_CFG_IEEE_754_BUG
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#define CGAL_EXPONENT_DOUBLE_MASK 0x7ff00000
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#define CGAL_MANTISSA_DOUBLE_MASK 0x000fffff
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inline
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bool
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is_finite_by_mask_long_double(unsigned int h)
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{
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unsigned int e = h & CGAL_EXPONENT_DOUBLE_MASK;
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return ( ( e ^ CGAL_EXPONENT_DOUBLE_MASK ) != 0 );
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}
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inline
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bool
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is_nan_by_mask_long_double(unsigned int h, unsigned int l)
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{
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if ( is_finite_by_mask_long_double(h) )
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return false;
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return (( h & CGAL_MANTISSA_DOUBLE_MASK ) != 0) || (( l & 0xffffffff ) != 0);
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}
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template<>
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class Is_valid< long double >
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: public CGAL::cpp98::unary_function< long double, bool > {
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public :
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bool operator()( const long double& x ) const {
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double d = x;
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IEEE_754_double* p = reinterpret_cast<IEEE_754_double*>(&d);
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return ! ( is_nan_by_mask_long_double( p->c.H, p->c.L ));
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}
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};
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#else
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template<>
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class Is_valid< long double >
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: public CGAL::cpp98::unary_function< long double, bool > {
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public :
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bool operator()( const long double& x ) const {
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return (x == x);
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}
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};
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#endif
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template <> class Algebraic_structure_traits< long double >
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: public Algebraic_structure_traits_base< long double,
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Field_with_kth_root_tag > {
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public:
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typedef Tag_false Is_exact;
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typedef Tag_true Is_numerical_sensitive;
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class Sqrt
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: public CGAL::cpp98::unary_function< Type, Type > {
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public:
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Type operator()( const Type& x ) const {
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return std::sqrt( x );
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}
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};
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class Kth_root
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:public CGAL::cpp98::binary_function<int, Type, Type > {
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public:
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Type operator()( int k,
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const Type& x) const {
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CGAL_precondition_msg( k > 0,
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"'k' must be positive for k-th roots");
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return std::pow(x, (long double)1.0 / (long double)(k));
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};
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};
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};
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template <> class Real_embeddable_traits< long double >
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: public INTERN_RET::Real_embeddable_traits_base< long double , CGAL::Tag_true > {
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public:
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class To_interval
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: public CGAL::cpp98::unary_function< Type, std::pair< double, double > > {
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public:
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std::pair<double, double> operator()( const Type& x ) const {
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// The conversion long double to double does not always follow the
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// rounding mode (e.g. on MacIntel/g++-4.0.2). So let's do a naive
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// conversion to double, then widen the interval.
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return (Interval_nt<>((double)x)+Interval_nt<>::smallest()).pair();
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#if 0
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// We hope that the long double -> double conversion
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// follows the current rounding mode.
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Protect_FPU_rounding<true> P(CGAL_FE_UPWARD);
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volatile long double mx = -x; // needed otherwise the conversion can
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// get factorized between d and -d...
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if (x>0)
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return std::make_pair(- static_cast<double>(CGAL_IA_FORCE_TO_DOUBLE(mx)),
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static_cast<double>(CGAL_IA_FORCE_TO_DOUBLE(x)));
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else
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return std::make_pair((double) CGAL_IA_FORCE_TO_DOUBLE(x),
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- (double) CGAL_IA_FORCE_TO_DOUBLE(mx));
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#endif
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}
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};
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// Is_finite depends on platform
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class Is_finite
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: public CGAL::cpp98::unary_function< Type, bool > {
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public:
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bool operator()( const Type& x ) const {
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#ifdef CGAL_CFG_IEEE_754_BUG
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Type d = x;
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IEEE_754_double* p = reinterpret_cast<IEEE_754_double*>(&d);
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return is_finite_by_mask_long_double( p->c.H );
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#else
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return (x == x) && (is_valid(x-x));
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#endif
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}
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};
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};
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} //namespace CGAL
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#endif // CGAL_LONG_DOUBLE_H
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