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/*
* Created by Martin on 07/11/2017.
*
* 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)
*/
#include "catch_matchers_floating.h"
#include "catch_to_string.hpp"
#include "catch_tostring.h"
#include <cstdlib>
#include <cstdint>
#include <cstring>
#include <stdexcept>
namespace Catch {
namespace Matchers {
namespace Floating {
enum class FloatingPointKind : uint8_t {
Float,
Double
};
}
}
}
namespace {
template <typename T>
struct Converter;
template <>
struct Converter<float> {
static_assert(sizeof(float) == sizeof(int32_t), "Important ULP matcher assumption violated");
Converter(float f) {
std::memcpy(&i, &f, sizeof(f));
}
int32_t i;
};
template <>
struct Converter<double> {
static_assert(sizeof(double) == sizeof(int64_t), "Important ULP matcher assumption violated");
Converter(double d) {
std::memcpy(&i, &d, sizeof(d));
}
int64_t i;
};
template <typename T>
auto convert(T t) -> Converter<T> {
return Converter<T>(t);
}
template <typename FP>
bool almostEqualUlps(FP lhs, FP rhs, int maxUlpDiff) {
// Comparison with NaN should always be false.
// This way we can rule it out before getting into the ugly details
if (std::isnan(lhs) || std::isnan(rhs)) {
return false;
}
auto lc = convert(lhs);
auto rc = convert(rhs);
if ((lc.i < 0) != (rc.i < 0)) {
// Potentially we can have +0 and -0
return lhs == rhs;
}
auto ulpDiff = std::abs(lc.i - rc.i);
return ulpDiff <= maxUlpDiff;
}
}
namespace Catch {
namespace Matchers {
namespace Floating {
WithinAbsMatcher::WithinAbsMatcher(double target, double margin)
:m_target{ target }, m_margin{ margin } {
if (m_margin < 0) {
throw std::domain_error("Allowed margin difference has to be >= 0");
}
}
// 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, int ulps, FloatingPointKind baseType)
:m_target{ target }, m_ulps{ ulps }, m_type{ baseType } {
if (m_ulps < 0) {
throw std::domain_error("Allowed ulp difference has to be >= 0");
}
}
bool WithinUlpsMatcher::match(double const& matchee) const {
switch (m_type) {
case FloatingPointKind::Float:
return almostEqualUlps<float>(static_cast<float>(matchee), static_cast<float>(m_target), m_ulps);
case FloatingPointKind::Double:
return almostEqualUlps<double>(matchee, m_target, m_ulps);
default:
throw std::domain_error("Unknown FloatingPointKind value");
}
}
std::string WithinUlpsMatcher::describe() const {
return "is within " + Catch::to_string(m_ulps) + " ULPs of " + ::Catch::Detail::stringify(m_target) + ((m_type == FloatingPointKind::Float)? "f" : "");
}
}// namespace Floating
Floating::WithinUlpsMatcher WithinULP(double target, int maxUlpDiff) {
return Floating::WithinUlpsMatcher(target, maxUlpDiff, Floating::FloatingPointKind::Double);
}
Floating::WithinUlpsMatcher WithinULP(float target, int maxUlpDiff) {
return Floating::WithinUlpsMatcher(target, maxUlpDiff, Floating::FloatingPointKind::Float);
}
Floating::WithinAbsMatcher WithinAbs(double target, double margin) {
return Floating::WithinAbsMatcher(target, margin);
}
} // namespace Matchers
} // namespace Catch
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