boost/test/floating_point_comparison.hpp
// (C) Copyright Gennadiy Rozental 2001-2005.
// Distributed under the Boost Software License, Version 1.0.
// (See accompanying file LICENSE_1_0.txt or copy at
// http://www.boost.org/LICENSE_1_0.txt)
// See http://www.boost.org/libs/test for the library home page.
//
// File : $RCSfile: floating_point_comparison.hpp,v $
//
// Version : $Revision: 1.26.2.2 $
//
// Description : defines algoirthms for comparing 2 floating point values
// ***************************************************************************
#ifndef BOOST_TEST_FLOATING_POINT_COMPARISON_HPP_071894GER
#define BOOST_TEST_FLOATING_POINT_COMPARISON_HPP_071894GER
#include <boost/limits.hpp> // for std::numeric_limits
#include <boost/test/utils/class_properties.hpp>
#include <boost/test/detail/suppress_warnings.hpp>
//____________________________________________________________________________//
namespace boost {
namespace test_tools {
using unit_test::readonly_property;
// ************************************************************************** //
// ************** floating_point_comparison_type ************** //
// ************************************************************************** //
enum floating_point_comparison_type {
FPC_STRONG, // "Very close" - equation 1' in docs, the default
FPC_WEAK // "Close enough" - equation 2' in docs.
};
// ************************************************************************** //
// ************** details ************** //
// ************************************************************************** //
namespace tt_detail {
// FPT is Floating-Point type, float, double, long double or User-Defined.
template<typename FPT>
inline FPT
fpt_abs( FPT arg )
{
return arg < static_cast<FPT>(0) ? -arg : arg;
}
//____________________________________________________________________________//
// both f1 and f2 are unsigned here
template<typename FPT>
inline FPT
safe_fpt_division( FPT f1, FPT f2 )
{
// Avoid overflow.
if( f2 < static_cast<FPT>(1) && f1 > f2 * (std::numeric_limits<FPT>::max)() )
return (std::numeric_limits<FPT>::max)();
// Avoid underflow.
if( f1 == static_cast<FPT>(0) ||
f2 > static_cast<FPT>(1) && f1 < f2 * (std::numeric_limits<FPT>::min)() )
return static_cast<FPT>(0);
return f1/f2;
}
//____________________________________________________________________________//
} // namespace tt_detail
// ************************************************************************** //
// ************** tolerance presentation types ************** //
// ************************************************************************** //
template<typename FPT>
struct percent_tolerance_t {
explicit percent_tolerance_t( FPT v ) : m_value( v ) {}
FPT m_value;
};
//____________________________________________________________________________//
template<typename Out,typename FPT>
Out& operator<<( Out& out, percent_tolerance_t<FPT> t )
{
return out << t.m_value;
}
//____________________________________________________________________________//
template<typename FPT>
inline percent_tolerance_t<FPT>
percent_tolerance( FPT v )
{
return percent_tolerance_t<FPT>( v );
}
//____________________________________________________________________________//
template<typename FPT>
struct fraction_tolerance_t {
explicit fraction_tolerance_t( FPT v ) : m_value( v ) {}
FPT m_value;
};
//____________________________________________________________________________//
template<typename Out,typename FPT>
Out& operator<<( Out& out, fraction_tolerance_t<FPT> t )
{
return out << t.m_value;
}
//____________________________________________________________________________//
template<typename FPT>
inline fraction_tolerance_t<FPT>
fraction_tolerance( FPT v )
{
return fraction_tolerance_t<FPT>( v );
}
//____________________________________________________________________________//
// ************************************************************************** //
// ************** close_at_tolerance ************** //
// ************************************************************************** //
template<typename FPT>
class close_at_tolerance {
public:
// Public typedefs
typedef bool result_type;
// Constructor
template<typename ToleranceBaseType>
explicit close_at_tolerance( percent_tolerance_t<ToleranceBaseType> tolerance,
floating_point_comparison_type fpc_type = FPC_STRONG )
: p_fraction_tolerance( tt_detail::fpt_abs( static_cast<FPT>(0.01)*tolerance.m_value ) )
, p_strong_or_weak( fpc_type == FPC_STRONG )
{}
template<typename ToleranceBaseType>
explicit close_at_tolerance( fraction_tolerance_t<ToleranceBaseType> tolerance,
floating_point_comparison_type fpc_type = FPC_STRONG )
: p_fraction_tolerance( tt_detail::fpt_abs( tolerance.m_value ) )
, p_strong_or_weak( fpc_type == FPC_STRONG )
{}
bool operator()( FPT left, FPT right ) const
{
FPT diff = tt_detail::fpt_abs( left - right );
FPT d1 = tt_detail::safe_fpt_division( diff, tt_detail::fpt_abs( right ) );
FPT d2 = tt_detail::safe_fpt_division( diff, tt_detail::fpt_abs( left ) );
return p_strong_or_weak
? (d1 <= p_fraction_tolerance && d2 <= p_fraction_tolerance)
: (d1 <= p_fraction_tolerance || d2 <= p_fraction_tolerance);
}
// Public properties
readonly_property<FPT> p_fraction_tolerance;
readonly_property<bool> p_strong_or_weak;
};
//____________________________________________________________________________//
// ************************************************************************** //
// ************** check_is_close ************** //
// ************************************************************************** //
struct BOOST_TEST_DECL check_is_close_t {
// Public typedefs
typedef bool result_type;
template<typename FPT, typename ToleranceBaseType>
bool
operator()( FPT left, FPT right, percent_tolerance_t<ToleranceBaseType> tolerance,
floating_point_comparison_type fpc_type = FPC_STRONG )
{
close_at_tolerance<FPT> pred( tolerance, fpc_type );
return pred( left, right );
}
template<typename FPT, typename ToleranceBaseType>
bool
operator()( FPT left, FPT right, fraction_tolerance_t<ToleranceBaseType> tolerance,
floating_point_comparison_type fpc_type = FPC_STRONG )
{
close_at_tolerance<FPT> pred( tolerance, fpc_type );
return pred( left, right );
}
};
namespace {
check_is_close_t check_is_close;
}
//____________________________________________________________________________//
// ************************************************************************** //
// ************** check_is_small ************** //
// ************************************************************************** //
struct BOOST_TEST_DECL check_is_small_t {
// Public typedefs
typedef bool result_type;
template<typename FPT>
bool
operator()( FPT fpv, FPT tolerance )
{
return tt_detail::fpt_abs( fpv ) < tt_detail::fpt_abs( tolerance );
}
};
namespace {
check_is_small_t check_is_small;
}
//____________________________________________________________________________//
} // namespace test_tools
} // namespace boost
//____________________________________________________________________________//
#include <boost/test/detail/enable_warnings.hpp>
// ***************************************************************************
// Revision History :
//
// $Log: floating_point_comparison.hpp,v $
// Revision 1.26.2.2 2006/11/30 14:41:21 jhunold
// Merge from HEAD: Remove unnecessary export makro.
//
// Revision 1.26.2.1 2006/05/22 17:39:12 johnmaddock
// Fix min/max guidelines violation.
//
// Revision 1.26 2006/03/16 07:31:06 vladimir_prus
// Fix compile error on MSVC due to max and min being defined as macros.
//
// Revision 1.25 2006/03/13 18:28:25 rogeeff
// warnings eliminated
//
// Revision 1.24 2005/12/14 05:07:28 rogeeff
// introduced an ability to test on closeness based on either percentage dirven tolerance or fraction driven one
//
// Revision 1.23 2005/05/29 08:54:57 rogeeff
// allow bind usage
//
// Revision 1.22 2005/02/21 10:21:40 rogeeff
// check_is_small implemented
// check functions implemented as function objects
//
// Revision 1.21 2005/02/20 08:27:05 rogeeff
// This a major update for Boost.Test framework. See release docs for complete list of fixes/updates
//
// Revision 1.20 2005/02/01 06:40:06 rogeeff
// copyright update
// old log entries removed
// minor stilistic changes
// depricated tools removed
//
// Revision 1.19 2005/01/22 19:22:12 rogeeff
// implementation moved into headers section to eliminate dependency of included/minimal component on src directory
//
// ***************************************************************************
#endif // BOOST_FLOATING_POINT_COMAPARISON_HPP_071894GER