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/*=========================================================================
*
* Copyright NumFOCUS
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* https://www.apache.org/licenses/LICENSE-2.0.txt
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
*=========================================================================*/
// First include the header file to be tested:
#include "itkNumberToString.h"
#include <gtest/gtest.h>
#include <cmath> // For std::pow.
namespace
{
template <typename>
constexpr const char * floatingPointTypeName = "unspecified type";
template <>
constexpr const char * floatingPointTypeName<float> = "float";
template <>
constexpr const char * floatingPointTypeName<double> = "double";
template <typename TValue>
void
Test_all_digits()
{
const itk::NumberToString<TValue> numberToString{};
for (auto i = 9; i >= 0; --i)
{
EXPECT_EQ(numberToString(i), std::to_string(i));
}
}
template <typename TValue>
void
Test_non_finite_special_floating_point_values()
{
using NumericLimitsType = std::numeric_limits<TValue>;
const itk::NumberToString<TValue> numberToString{};
const auto message = std::string("Floating point type: ") + floatingPointTypeName<TValue>;
EXPECT_EQ(numberToString(NumericLimitsType::quiet_NaN()), "NaN") << message;
EXPECT_EQ(numberToString(NumericLimitsType::infinity()), "Infinity") << message;
EXPECT_EQ(numberToString(-NumericLimitsType::infinity()), "-Infinity") << message;
}
template <typename TValue>
void
Test_round_trip_of_finite_numeric_limits()
{
using NumericLimitsType = std::numeric_limits<TValue>;
const itk::NumberToString<TValue> numberToString{};
const auto message = std::string("Floating point type: ") + floatingPointTypeName<TValue>;
for (const TValue expectedValue : { NumericLimitsType::lowest(),
NumericLimitsType::epsilon(),
NumericLimitsType::round_error(),
NumericLimitsType::denorm_min(),
NumericLimitsType::min(),
NumericLimitsType::max() })
{
std::istringstream inputStream{ numberToString(expectedValue) };
EXPECT_FALSE(inputStream.eof()) << message;
TValue actualValue;
inputStream >> actualValue;
EXPECT_TRUE(inputStream.eof()) << message;
EXPECT_EQ(actualValue, expectedValue) << message;
}
}
template <typename TValue>
void
Test_decimal_notation_supports_up_to_twentyone_digits()
{
const itk::NumberToString<TValue> numberToString{};
const auto message = std::string("Floating point type: ") + floatingPointTypeName<TValue>;
for (int8_t exponent{ 20 }; exponent > 0; --exponent)
{
const TValue power_of_ten{ std::pow(TValue{ 10 }, static_cast<TValue>(exponent)) };
// Test +/- 10 ^ exponent
EXPECT_EQ(numberToString(power_of_ten), '1' + std::string(exponent, '0')) << message;
EXPECT_EQ(numberToString(-power_of_ten), "-1" + std::string(exponent, '0')) << message;
}
for (int8_t exponent{ -6 }; exponent < 0; ++exponent)
{
const TValue power_of_ten{ std::pow(TValue{ 10 }, static_cast<TValue>(exponent)) };
// Test +/- 10 ^ exponent
EXPECT_EQ(numberToString(power_of_ten), "0." + std::string(-1 - exponent, '0') + '1') << message;
EXPECT_EQ(numberToString(-power_of_ten), "-0." + std::string(-1 - exponent, '0') + '1') << message;
}
}
template <typename TValue>
void
Test_default_specialization_of_NumberToString()
{
using NumericLimitsType = std::numeric_limits<TValue>;
for (const TValue value : { NumericLimitsType::lowest(),
NumericLimitsType::denorm_min(),
TValue(),
NumericLimitsType::epsilon(),
NumericLimitsType::min(),
NumericLimitsType::max(),
NumericLimitsType::infinity(),
NumericLimitsType::quiet_NaN() })
{
// Expect the same string from the default specialization `NumberToString<>` as from the TValue specific
// `NumberToString<TValue>`.
EXPECT_EQ(itk::NumberToString<>()(value), itk::NumberToString<TValue>()(value));
}
}
template <typename TValue>
void
Test_ConvertNumberToString()
{
using NumericLimitsType = std::numeric_limits<TValue>;
for (const TValue value : { NumericLimitsType::lowest(),
NumericLimitsType::denorm_min(),
TValue(),
NumericLimitsType::epsilon(),
NumericLimitsType::min(),
NumericLimitsType::max(),
NumericLimitsType::infinity(),
NumericLimitsType::quiet_NaN() })
{
// Expect the same string from `ConvertNumberToString` as from `NumberToString<TValue>`.
EXPECT_EQ(itk::ConvertNumberToString(value), itk::NumberToString<TValue>()(value));
}
}
} // namespace
// Tests NumberToString for 0 to 9.
TEST(NumberToString, SupportsAllDigits)
{
Test_all_digits<int>();
Test_all_digits<float>();
Test_all_digits<double>();
}
// Tests that the function object returns a unique string for both positive and negative zero.
TEST(NumberToString, HasUniqueZeroString)
{
const std::string expectedZeroString = "0";
EXPECT_EQ(itk::NumberToString<int>{}(0), expectedZeroString);
EXPECT_EQ(itk::NumberToString<float>{}(+0.0f), expectedZeroString);
EXPECT_EQ(itk::NumberToString<float>{}(-0.0f), expectedZeroString);
EXPECT_EQ(itk::NumberToString<double>{}(+0.0), expectedZeroString);
EXPECT_EQ(itk::NumberToString<double>{}(-0.0), expectedZeroString);
}
TEST(NumberToString, NonFiniteSpecialFloatingPointValues)
{
Test_non_finite_special_floating_point_values<float>();
Test_non_finite_special_floating_point_values<double>();
}
TEST(NumberToString, RoundTripOfFiniteFloatingPointNumericLimits)
{
Test_round_trip_of_finite_numeric_limits<float>();
Test_round_trip_of_finite_numeric_limits<double>();
}
TEST(NumberToString, DecimalNotationUpTo21Digits)
{
Test_decimal_notation_supports_up_to_twentyone_digits<float>();
Test_decimal_notation_supports_up_to_twentyone_digits<double>();
}
TEST(NumberToString, DefaultSpecialization)
{
Test_default_specialization_of_NumberToString<int8_t>();
Test_default_specialization_of_NumberToString<uint8_t>();
Test_default_specialization_of_NumberToString<intmax_t>();
Test_default_specialization_of_NumberToString<uintmax_t>();
Test_default_specialization_of_NumberToString<float>();
Test_default_specialization_of_NumberToString<double>();
}
TEST(NumberToString, ConvertNumberToString)
{
Test_ConvertNumberToString<int8_t>();
Test_ConvertNumberToString<uint8_t>();
Test_ConvertNumberToString<intmax_t>();
Test_ConvertNumberToString<uintmax_t>();
Test_ConvertNumberToString<float>();
Test_ConvertNumberToString<double>();
}
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