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// Copyright (c) 1999,2007 Utrecht University (The Netherlands),
// ETH Zurich (Switzerland), Freie Universitaet Berlin (Germany),
// INRIA Sophia-Antipolis (France), Martin-Luther-University Halle-Wittenberg
// (Germany), Max-Planck-Institute Saarbruecken (Germany), RISC Linz (Austria),
// and Tel-Aviv University (Israel). 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; version 2.1 of the License.
// See the file LICENSE.LGPL distributed with CGAL.
//
// 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: svn+ssh://scm.gforge.inria.fr/svn/cgal/branches/CGAL-3.5-branch/Number_types/include/CGAL/double.h $
// $Id: double.h 44911 2008-08-12 13:09:51Z spion $
//
//
// Author(s) : Geert-Jan Giezeman, Michael Hemmer
#ifndef CGAL_DOUBLE_H
#define CGAL_DOUBLE_H
#include <CGAL/number_type_basic.h>
#include <utility>
#include <cmath>
#include <math.h> // for nextafter
#include <limits>
#ifdef _MSC_VER
#include <cfloat>
#endif
#ifdef CGAL_CFG_IEEE_754_BUG
# include <CGAL/IEEE_754_unions.h>
#endif
CGAL_BEGIN_NAMESPACE
#ifdef CGAL_CFG_IEEE_754_BUG
#define CGAL_EXPONENT_DOUBLE_MASK 0x7ff00000
#define CGAL_MANTISSA_DOUBLE_MASK 0x000fffff
inline
bool
is_finite_by_mask_double(unsigned int h)
{
unsigned int e = h & CGAL_EXPONENT_DOUBLE_MASK;
return ( ( e ^ CGAL_EXPONENT_DOUBLE_MASK ) != 0 );
}
inline
bool
is_nan_by_mask_double(unsigned int h, unsigned int l)
{
if ( is_finite_by_mask_double(h) )
return false;
return (( h & CGAL_MANTISSA_DOUBLE_MASK ) != 0) || (( l & 0xffffffff ) != 0);
}
template<>
class Is_valid< double >
: public std::unary_function< double, bool > {
public :
bool operator()( const double& x ) const{
double d = x;
IEEE_754_double* p = reinterpret_cast<IEEE_754_double*>(&d);
return ! ( is_nan_by_mask_double( p->c.H, p->c.L ));
}
};
#else
template<>
class Is_valid< double >
: public std::unary_function< double, bool > {
public :
bool operator()( const double& x ) const {
#ifdef _MSC_VER
return ! _isnan(x);
#else
return (x == x);
#endif
}
};
#endif
template <> class Algebraic_structure_traits< double >
: public Algebraic_structure_traits_base< double,
Field_with_kth_root_tag > {
public:
typedef Tag_false Is_exact;
typedef Tag_true Is_numerical_sensitive;
class Sqrt
: public std::unary_function< Type, Type > {
public:
Type operator()( const Type& x ) const {
return std::sqrt( x );
}
};
class Kth_root
: public std::binary_function<int, Type, Type> {
public:
Type operator()( int k,
const Type& x) const {
CGAL_precondition_msg( k > 0, "'k' must be positive for k-th roots");
return std::pow(x, 1.0 / double(k));
}
};
};
template <> class Real_embeddable_traits< double >
: public INTERN_RET::Real_embeddable_traits_base< double , CGAL::Tag_true> {
public:
// GCC is faster with std::fabs().
#ifdef __GNUG__
class Abs
: public std::unary_function< Type, Type > {
public:
Type operator()( const Type& x ) const {
return std::fabs( x );
}
};
#endif
// Is_finite depends on platform
class Is_finite
: public std::unary_function< Type, bool > {
public :
bool operator()( const Type& x ) const {
#ifdef CGAL_CFG_IEEE_754_BUG
Type d = x;
IEEE_754_double* p = reinterpret_cast<IEEE_754_double*>(&d);
return is_finite_by_mask_double( p->c.H );
#elif defined CGAL_CFG_NUMERIC_LIMITS_BUG
return (x == x) && (is_valid(x-x));
#else
return (x != std::numeric_limits<Type>::infinity())
&& (-x != std::numeric_limits<Type>::infinity())
&& is_valid(x);
#endif
}
};
};
inline
double
nextafter(double d1, double d2)
{
#ifdef CGAL_CFG_NO_NEXTAFTER
return _nextafter(d1, d2); // works at least for VC++-7.1
#else
return ::nextafter(d1,d2);
#endif
}
inline
bool
is_integer(double d)
{
return CGAL::is_finite(d) && (std::ceil(d) == d);
}
// Returns a pair of integers <num,den> such that d == num/den.
inline
std::pair<double, double>
split_numerator_denominator(double d)
{
// Note that it could probably be optimized.
double num = d;
double den = 1.0;
while (std::ceil(num) != num)
{
num *= 2.0;
den *= 2.0;
}
CGAL_postcondition(d == num/den);
return std::make_pair(num, den);
}
CGAL_END_NAMESPACE
#endif // CGAL_DOUBLE_H
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