287 lines
9.9 KiB
C++
287 lines
9.9 KiB
C++
// (C) Copyright Gennadiy Rozental 2001-2008.
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// Distributed under the Boost Software License, Version 1.0.
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// (See accompanying file LICENSE_1_0.txt or copy at
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// http://www.boost.org/LICENSE_1_0.txt)
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// See http://www.boost.org/libs/test for the library home page.
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//
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// File : $RCSfile$
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//
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// Version : $Revision: 57992 $
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//
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// Description : defines algoirthms for comparing 2 floating point values
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// ***************************************************************************
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#ifndef BOOST_TEST_FLOATING_POINT_COMPARISON_HPP_071894GER
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#define BOOST_TEST_FLOATING_POINT_COMPARISON_HPP_071894GER
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// Boost.Test
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#include <boost/test/detail/global_typedef.hpp>
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#include <boost/test/utils/class_properties.hpp>
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#include <boost/test/predicate_result.hpp>
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// Boost
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#include <boost/limits.hpp> // for std::numeric_limits
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#include <boost/numeric/conversion/conversion_traits.hpp> // for numeric::conversion_traits
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#include <boost/static_assert.hpp>
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#include <boost/test/detail/suppress_warnings.hpp>
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//____________________________________________________________________________//
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namespace boost {
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namespace test_tools {
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using unit_test::readonly_property;
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// ************************************************************************** //
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// ************** floating_point_comparison_type ************** //
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// ************************************************************************** //
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enum floating_point_comparison_type {
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FPC_STRONG, // "Very close" - equation 1' in docs, the default
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FPC_WEAK // "Close enough" - equation 2' in docs.
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};
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// ************************************************************************** //
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// ************** details ************** //
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// ************************************************************************** //
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namespace tt_detail {
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// FPT is Floating-Point Type: float, double, long double or User-Defined.
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template<typename FPT>
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inline FPT
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fpt_abs( FPT fpv )
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{
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return fpv < static_cast<FPT>(0) ? -fpv : fpv;
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}
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//____________________________________________________________________________//
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template<typename FPT>
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struct fpt_limits {
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static FPT min_value()
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{
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return std::numeric_limits<FPT>::is_specialized
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? (std::numeric_limits<FPT>::min)()
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: 0;
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}
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static FPT max_value()
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{
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return std::numeric_limits<FPT>::is_specialized
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? (std::numeric_limits<FPT>::max)()
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: static_cast<FPT>(1000000); // for the our purpuses it doesn't really matter what value is returned here
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}
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};
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//____________________________________________________________________________//
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// both f1 and f2 are unsigned here
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template<typename FPT>
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inline FPT
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safe_fpt_division( FPT f1, FPT f2 )
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{
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// Avoid overflow.
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if( (f2 < static_cast<FPT>(1)) && (f1 > f2*fpt_limits<FPT>::max_value()) )
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return fpt_limits<FPT>::max_value();
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// Avoid underflow.
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if( (f1 == static_cast<FPT>(0)) ||
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((f2 > static_cast<FPT>(1)) && (f1 < f2*fpt_limits<FPT>::min_value())) )
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return static_cast<FPT>(0);
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return f1/f2;
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}
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//____________________________________________________________________________//
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} // namespace tt_detail
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// ************************************************************************** //
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// ************** tolerance presentation types ************** //
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// ************************************************************************** //
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template<typename FPT>
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struct percent_tolerance_t {
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explicit percent_tolerance_t( FPT v ) : m_value( v ) {}
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FPT m_value;
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};
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//____________________________________________________________________________//
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template<typename Out,typename FPT>
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Out& operator<<( Out& out, percent_tolerance_t<FPT> t )
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{
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return out << t.m_value;
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}
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//____________________________________________________________________________//
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template<typename FPT>
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inline percent_tolerance_t<FPT>
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percent_tolerance( FPT v )
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{
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return percent_tolerance_t<FPT>( v );
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}
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//____________________________________________________________________________//
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template<typename FPT>
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struct fraction_tolerance_t {
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explicit fraction_tolerance_t( FPT v ) : m_value( v ) {}
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FPT m_value;
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};
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//____________________________________________________________________________//
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template<typename Out,typename FPT>
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Out& operator<<( Out& out, fraction_tolerance_t<FPT> t )
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{
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return out << t.m_value;
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}
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//____________________________________________________________________________//
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template<typename FPT>
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inline fraction_tolerance_t<FPT>
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fraction_tolerance( FPT v )
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{
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return fraction_tolerance_t<FPT>( v );
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}
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//____________________________________________________________________________//
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// ************************************************************************** //
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// ************** close_at_tolerance ************** //
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// ************************************************************************** //
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template<typename FPT>
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class close_at_tolerance {
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public:
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// Public typedefs
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typedef bool result_type;
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// Constructor
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template<typename ToleranceBaseType>
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explicit close_at_tolerance( percent_tolerance_t<ToleranceBaseType> tolerance,
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floating_point_comparison_type fpc_type = FPC_STRONG )
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: p_fraction_tolerance( tt_detail::fpt_abs( static_cast<FPT>(0.01)*tolerance.m_value ) )
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, p_strong_or_weak( fpc_type == FPC_STRONG )
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, m_report_modifier( 100. )
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{}
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template<typename ToleranceBaseType>
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explicit close_at_tolerance( fraction_tolerance_t<ToleranceBaseType> tolerance,
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floating_point_comparison_type fpc_type = FPC_STRONG )
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: p_fraction_tolerance( tt_detail::fpt_abs( tolerance.m_value ) )
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, p_strong_or_weak( fpc_type == FPC_STRONG )
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, m_report_modifier( 1. )
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{}
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predicate_result operator()( FPT left, FPT right ) const
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{
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FPT diff = tt_detail::fpt_abs( left - right );
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FPT d1 = tt_detail::safe_fpt_division( diff, tt_detail::fpt_abs( right ) );
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FPT d2 = tt_detail::safe_fpt_division( diff, tt_detail::fpt_abs( left ) );
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predicate_result res( p_strong_or_weak
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? (d1 <= p_fraction_tolerance.get() && d2 <= p_fraction_tolerance.get())
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: (d1 <= p_fraction_tolerance.get() || d2 <= p_fraction_tolerance.get()) );
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if( !res )
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res.message() << (( d1 <= p_fraction_tolerance.get() ? d2 : d1 ) * m_report_modifier);
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return res;
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}
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// Public properties
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readonly_property<FPT> p_fraction_tolerance;
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readonly_property<bool> p_strong_or_weak;
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private:
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// Data members
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FPT m_report_modifier;
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};
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//____________________________________________________________________________//
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// ************************************************************************** //
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// ************** check_is_close ************** //
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// ************************************************************************** //
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struct BOOST_TEST_DECL check_is_close_t {
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// Public typedefs
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typedef bool result_type;
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template<typename FPT1, typename FPT2, typename ToleranceBaseType>
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predicate_result
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operator()( FPT1 left, FPT2 right, percent_tolerance_t<ToleranceBaseType> tolerance,
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floating_point_comparison_type fpc_type = FPC_STRONG ) const
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{
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// deduce "better" type from types of arguments being compared
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// if one type is floating and the second integral we use floating type and
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// value of integral type is promoted to the floating. The same for float and double
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// But we don't want to compare two values of integral types using this tool.
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typedef typename numeric::conversion_traits<FPT1,FPT2>::supertype FPT;
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BOOST_STATIC_ASSERT( !is_integral<FPT>::value );
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close_at_tolerance<FPT> pred( tolerance, fpc_type );
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return pred( left, right );
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}
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template<typename FPT1, typename FPT2, typename ToleranceBaseType>
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predicate_result
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operator()( FPT1 left, FPT2 right, fraction_tolerance_t<ToleranceBaseType> tolerance,
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floating_point_comparison_type fpc_type = FPC_STRONG ) const
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{
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// same as in a comment above
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typedef typename numeric::conversion_traits<FPT1,FPT2>::supertype FPT;
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BOOST_STATIC_ASSERT( !is_integral<FPT>::value );
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close_at_tolerance<FPT> pred( tolerance, fpc_type );
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return pred( left, right );
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}
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};
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namespace {
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check_is_close_t const& check_is_close = unit_test::ut_detail::static_constant<check_is_close_t>::value;
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}
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//____________________________________________________________________________//
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// ************************************************************************** //
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// ************** check_is_small ************** //
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// ************************************************************************** //
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struct BOOST_TEST_DECL check_is_small_t {
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// Public typedefs
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typedef bool result_type;
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template<typename FPT>
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bool
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operator()( FPT fpv, FPT tolerance ) const
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{
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return tt_detail::fpt_abs( fpv ) < tt_detail::fpt_abs( tolerance );
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}
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};
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namespace {
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check_is_small_t const& check_is_small = unit_test::ut_detail::static_constant<check_is_small_t>::value;
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}
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//____________________________________________________________________________//
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} // namespace test_tools
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} // namespace boost
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//____________________________________________________________________________//
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#include <boost/test/detail/enable_warnings.hpp>
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#endif // BOOST_FLOATING_POINT_COMAPARISON_HPP_071894GER
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