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authorLexi Winter <lexi@le-fay.org>2025-06-29 19:25:29 +0100
committerLexi Winter <lexi@le-fay.org>2025-06-29 19:25:29 +0100
commitbc524d70253a4ab2fe40c3ca3e5666e267c0a4d1 (patch)
tree1e629e7b46b1d9972a973bc93fd100bcebd395be /src/catch2/matchers/catch_matchers_floating_point.cpp
downloadnihil-548ea226e1944e077d3ff305df43ef6b366b03f4.tar.gz
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Diffstat (limited to 'src/catch2/matchers/catch_matchers_floating_point.cpp')
-rw-r--r--src/catch2/matchers/catch_matchers_floating_point.cpp226
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diff --git a/src/catch2/matchers/catch_matchers_floating_point.cpp b/src/catch2/matchers/catch_matchers_floating_point.cpp
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+
+// Copyright Catch2 Authors
+// Distributed under the Boost Software License, Version 1.0.
+// (See accompanying file LICENSE.txt or copy at
+// https://www.boost.org/LICENSE_1_0.txt)
+
+// SPDX-License-Identifier: BSL-1.0
+#include <catch2/matchers/catch_matchers_floating_point.hpp>
+#include <catch2/internal/catch_enforce.hpp>
+#include <catch2/internal/catch_polyfills.hpp>
+#include <catch2/internal/catch_to_string.hpp>
+#include <catch2/catch_tostring.hpp>
+#include <catch2/internal/catch_floating_point_helpers.hpp>
+
+#include <algorithm>
+#include <cmath>
+#include <cstdlib>
+#include <cstdint>
+#include <sstream>
+#include <iomanip>
+#include <limits>
+
+
+namespace Catch {
+namespace {
+
+ template <typename FP>
+ bool almostEqualUlps(FP lhs, FP rhs, uint64_t maxUlpDiff) {
+ // Comparison with NaN should always be false.
+ // This way we can rule it out before getting into the ugly details
+ if (Catch::isnan(lhs) || Catch::isnan(rhs)) {
+ return false;
+ }
+
+ // This should also handle positive and negative zeros, infinities
+ const auto ulpDist = ulpDistance(lhs, rhs);
+
+ return ulpDist <= maxUlpDiff;
+ }
+
+
+template <typename FP>
+FP step(FP start, FP direction, uint64_t steps) {
+ for (uint64_t i = 0; i < steps; ++i) {
+ start = Catch::nextafter(start, direction);
+ }
+ return start;
+}
+
+// Performs equivalent check of std::fabs(lhs - rhs) <= margin
+// But without the subtraction to allow for INFINITY in comparison
+bool marginComparison(double lhs, double rhs, double margin) {
+ return (lhs + margin >= rhs) && (rhs + margin >= lhs);
+}
+
+template <typename FloatingPoint>
+void write(std::ostream& out, FloatingPoint num) {
+ out << std::scientific
+ << std::setprecision(std::numeric_limits<FloatingPoint>::max_digits10 - 1)
+ << num;
+}
+
+} // end anonymous namespace
+
+namespace Matchers {
+namespace Detail {
+
+ enum class FloatingPointKind : uint8_t {
+ Float,
+ Double
+ };
+
+} // end namespace Detail
+
+
+ WithinAbsMatcher::WithinAbsMatcher(double target, double margin)
+ :m_target{ target }, m_margin{ margin } {
+ CATCH_ENFORCE(margin >= 0, "Invalid margin: " << margin << '.'
+ << " Margin has to be non-negative.");
+ }
+
+ // Performs equivalent check of std::fabs(lhs - rhs) <= margin
+ // But without the subtraction to allow for INFINITY in comparison
+ bool WithinAbsMatcher::match(double const& matchee) const {
+ return (matchee + m_margin >= m_target) && (m_target + m_margin >= matchee);
+ }
+
+ std::string WithinAbsMatcher::describe() const {
+ return "is within " + ::Catch::Detail::stringify(m_margin) + " of " + ::Catch::Detail::stringify(m_target);
+ }
+
+
+ WithinUlpsMatcher::WithinUlpsMatcher(double target, uint64_t ulps, Detail::FloatingPointKind baseType)
+ :m_target{ target }, m_ulps{ ulps }, m_type{ baseType } {
+ CATCH_ENFORCE(m_type == Detail::FloatingPointKind::Double
+ || m_ulps < (std::numeric_limits<uint32_t>::max)(),
+ "Provided ULP is impossibly large for a float comparison.");
+ CATCH_ENFORCE( std::numeric_limits<double>::is_iec559,
+ "WithinUlp matcher only supports platforms with "
+ "IEEE-754 compatible floating point representation" );
+ }
+
+#if defined(__clang__)
+#pragma clang diagnostic push
+// Clang <3.5 reports on the default branch in the switch below
+#pragma clang diagnostic ignored "-Wunreachable-code"
+#endif
+
+ bool WithinUlpsMatcher::match(double const& matchee) const {
+ switch (m_type) {
+ case Detail::FloatingPointKind::Float:
+ return almostEqualUlps<float>(static_cast<float>(matchee), static_cast<float>(m_target), m_ulps);
+ case Detail::FloatingPointKind::Double:
+ return almostEqualUlps<double>(matchee, m_target, m_ulps);
+ default:
+ CATCH_INTERNAL_ERROR( "Unknown Detail::FloatingPointKind value" );
+ }
+ }
+
+#if defined(__clang__)
+#pragma clang diagnostic pop
+#endif
+
+ std::string WithinUlpsMatcher::describe() const {
+ std::stringstream ret;
+
+ ret << "is within " << m_ulps << " ULPs of ";
+
+ if (m_type == Detail::FloatingPointKind::Float) {
+ write(ret, static_cast<float>(m_target));
+ ret << 'f';
+ } else {
+ write(ret, m_target);
+ }
+
+ ret << " ([";
+ if (m_type == Detail::FloatingPointKind::Double) {
+ write( ret,
+ step( m_target,
+ -std::numeric_limits<double>::infinity(),
+ m_ulps ) );
+ ret << ", ";
+ write( ret,
+ step( m_target,
+ std::numeric_limits<double>::infinity(),
+ m_ulps ) );
+ } else {
+ // We have to cast INFINITY to float because of MinGW, see #1782
+ write( ret,
+ step( static_cast<float>( m_target ),
+ -std::numeric_limits<float>::infinity(),
+ m_ulps ) );
+ ret << ", ";
+ write( ret,
+ step( static_cast<float>( m_target ),
+ std::numeric_limits<float>::infinity(),
+ m_ulps ) );
+ }
+ ret << "])";
+
+ return ret.str();
+ }
+
+ WithinRelMatcher::WithinRelMatcher(double target, double epsilon):
+ m_target(target),
+ m_epsilon(epsilon){
+ CATCH_ENFORCE(m_epsilon >= 0., "Relative comparison with epsilon < 0 does not make sense.");
+ CATCH_ENFORCE(m_epsilon < 1., "Relative comparison with epsilon >= 1 does not make sense.");
+ }
+
+ bool WithinRelMatcher::match(double const& matchee) const {
+ const auto relMargin = m_epsilon * (std::max)(std::fabs(matchee), std::fabs(m_target));
+ return marginComparison(matchee, m_target,
+ std::isinf(relMargin)? 0 : relMargin);
+ }
+
+ std::string WithinRelMatcher::describe() const {
+ Catch::ReusableStringStream sstr;
+ sstr << "and " << ::Catch::Detail::stringify(m_target) << " are within " << m_epsilon * 100. << "% of each other";
+ return sstr.str();
+ }
+
+
+WithinUlpsMatcher WithinULP(double target, uint64_t maxUlpDiff) {
+ return WithinUlpsMatcher(target, maxUlpDiff, Detail::FloatingPointKind::Double);
+}
+
+WithinUlpsMatcher WithinULP(float target, uint64_t maxUlpDiff) {
+ return WithinUlpsMatcher(target, maxUlpDiff, Detail::FloatingPointKind::Float);
+}
+
+WithinAbsMatcher WithinAbs(double target, double margin) {
+ return WithinAbsMatcher(target, margin);
+}
+
+WithinRelMatcher WithinRel(double target, double eps) {
+ return WithinRelMatcher(target, eps);
+}
+
+WithinRelMatcher WithinRel(double target) {
+ return WithinRelMatcher(target, std::numeric_limits<double>::epsilon() * 100);
+}
+
+WithinRelMatcher WithinRel(float target, float eps) {
+ return WithinRelMatcher(target, eps);
+}
+
+WithinRelMatcher WithinRel(float target) {
+ return WithinRelMatcher(target, std::numeric_limits<float>::epsilon() * 100);
+}
+
+
+
+bool IsNaNMatcher::match( double const& matchee ) const {
+ return std::isnan( matchee );
+}
+
+std::string IsNaNMatcher::describe() const {
+ using namespace std::string_literals;
+ return "is NaN"s;
+}
+
+IsNaNMatcher IsNaN() { return IsNaNMatcher(); }
+
+ } // namespace Matchers
+} // namespace Catch