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jviottijviotti
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Add Decimal float/double constructors (#2036)
Signed-off-by: Juan Cruz Viotti <jv@jviotti.com>
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‎src/lang/numeric/decimal.cc‎

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@@ -16,6 +16,17 @@
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#include <mpdecimal.h> // mpd_*
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namespace {
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template <typename FloatingPointType>
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requires std::is_floating_point_v<FloatingPointType>
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auto floating_point_to_string(const FloatingPointType value) -> std::string {
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std::ostringstream oss;
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oss << std::setprecision(std::numeric_limits<FloatingPointType>::max_digits10)
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<< value;
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return oss.str();
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}
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} // namespace
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namespace sourcemeta::core {
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struct Decimal::Data {
@@ -248,6 +259,12 @@ Decimal::Decimal(const std::uint64_t integral_value) {
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}
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}
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Decimal::Decimal(const float floating_point_value)
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: Decimal{floating_point_to_string(floating_point_value)} {}
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Decimal::Decimal(const double floating_point_value)
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: Decimal{floating_point_to_string(floating_point_value)} {}
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Decimal::Decimal(const char *const string_value) {
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new (this->storage) Data{};
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this->data()->value.flags = MPD_STATIC | MPD_STATIC_DATA;

‎src/lang/numeric/include/sourcemeta/core/numeric_decimal.h‎

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@@ -48,6 +48,12 @@ class SOURCEMETA_CORE_NUMERIC_EXPORT Decimal {
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/// Construct a decimal number from a 64-bit unsigned integer
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Decimal(std::uint64_t value);
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/// Construct a decimal number from a 32-bit float
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explicit Decimal(float value);
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/// Construct a decimal number from a 64-bit double
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explicit Decimal(double value);
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/// Construct a decimal number from a C-string
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explicit Decimal(const char *const value);
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‎test/numeric/numeric_decimal_test.cc‎

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@@ -759,6 +759,66 @@ TEST(Numeric_decimal, to_double_negative_infinity) {
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EXPECT_LT(result, 0.0);
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}
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TEST(Numeric_decimal, to_float_not_exactly_representable_gets_rounded) {
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const sourcemeta::core::Decimal value{"3.2"};
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EXPECT_FALSE(value.is_float());
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const float result{value.to_float()};
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EXPECT_FLOAT_EQ(result, 3.2f);
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}
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TEST(Numeric_decimal, to_double_not_exactly_representable_gets_rounded) {
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const sourcemeta::core::Decimal value{"3.2"};
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EXPECT_FALSE(value.is_double());
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const double result{value.to_double()};
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EXPECT_DOUBLE_EQ(result, 3.2);
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}
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TEST(Numeric_decimal, to_float_exceeds_max_float_throws) {
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const sourcemeta::core::Decimal value{"1e100"};
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EXPECT_FALSE(value.is_float());
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EXPECT_THROW(
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{ [[maybe_unused]] const float result = value.to_float(); },
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std::out_of_range);
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}
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TEST(Numeric_decimal, to_double_exceeds_max_double_throws) {
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const sourcemeta::core::Decimal value{"1e500"};
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EXPECT_FALSE(value.is_double());
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EXPECT_THROW(
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{ [[maybe_unused]] const double result = value.to_double(); },
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std::out_of_range);
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}
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TEST(Numeric_decimal, to_float_below_min_float_throws) {
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const sourcemeta::core::Decimal value{"1e-100"};
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EXPECT_FALSE(value.is_float());
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EXPECT_THROW(
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{ [[maybe_unused]] const float result = value.to_float(); },
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std::out_of_range);
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}
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TEST(Numeric_decimal, to_double_below_min_double_throws) {
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const sourcemeta::core::Decimal value{"1e-500"};
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EXPECT_FALSE(value.is_double());
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EXPECT_THROW(
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{ [[maybe_unused]] const double result = value.to_double(); },
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std::out_of_range);
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}
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TEST(Numeric_decimal, to_float_high_precision_gets_rounded) {
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const sourcemeta::core::Decimal value{"1.23456789"};
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EXPECT_FALSE(value.is_float());
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const float result{value.to_float()};
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EXPECT_FLOAT_EQ(result, 1.23456789f);
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}
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TEST(Numeric_decimal, to_double_high_precision_gets_rounded) {
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const sourcemeta::core::Decimal value{"1.234567890123456789"};
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EXPECT_FALSE(value.is_double());
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const double result{value.to_double()};
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EXPECT_DOUBLE_EQ(result, 1.234567890123456789);
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}
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TEST(Numeric_decimal, divisible_by_integer_true) {
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const sourcemeta::core::Decimal dividend{10};
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const sourcemeta::core::Decimal divisor{5};
@@ -1222,6 +1282,7 @@ TEST(Numeric_decimal, is_uint64_false_too_large) {
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const sourcemeta::core::Decimal value{"18446744073709551616"};
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EXPECT_FALSE(value.is_uint64());
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}
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TEST(Numeric_decimal, exception_conversion_syntax_invalid_string) {
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EXPECT_THROW(
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{ const sourcemeta::core::Decimal value{"not_a_number"}; },
@@ -1455,3 +1516,105 @@ TEST(Numeric_decimal, negative_zero_preserves_sign) {
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EXPECT_TRUE(copy.is_signed());
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EXPECT_TRUE(copy.is_zero());
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}
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TEST(Numeric_decimal, construct_from_float_simple) {
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const float value{3.5f};
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const sourcemeta::core::Decimal decimal{value};
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EXPECT_TRUE(decimal.is_float());
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EXPECT_TRUE(decimal.is_double());
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EXPECT_EQ(decimal.to_float(), 3.5f);
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EXPECT_EQ(decimal.to_double(), 3.5);
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EXPECT_EQ(decimal.to_string(), "3.5");
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}
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TEST(Numeric_decimal, construct_from_float_negative) {
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const float value{-7.25f};
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const sourcemeta::core::Decimal decimal{value};
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EXPECT_TRUE(decimal.is_float());
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EXPECT_TRUE(decimal.is_double());
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EXPECT_EQ(decimal.to_float(), -7.25f);
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EXPECT_EQ(decimal.to_double(), -7.25);
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EXPECT_EQ(decimal.to_string(), "-7.25");
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}
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TEST(Numeric_decimal, construct_from_float_zero) {
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const float value{0.0f};
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const sourcemeta::core::Decimal decimal{value};
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EXPECT_TRUE(decimal.is_float());
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EXPECT_TRUE(decimal.is_double());
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EXPECT_TRUE(decimal.is_zero());
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EXPECT_EQ(decimal.to_float(), 0.0f);
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EXPECT_EQ(decimal.to_double(), 0.0);
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}
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TEST(Numeric_decimal, construct_from_float_very_small) {
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const float value{0.125f};
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const sourcemeta::core::Decimal decimal{value};
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EXPECT_TRUE(decimal.is_float());
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EXPECT_TRUE(decimal.is_double());
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EXPECT_EQ(decimal.to_float(), 0.125f);
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EXPECT_EQ(decimal.to_double(), 0.125);
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EXPECT_EQ(decimal.to_string(), "0.125");
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}
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TEST(Numeric_decimal, construct_from_double_simple) {
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const double value{3.5};
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const sourcemeta::core::Decimal decimal{value};
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EXPECT_TRUE(decimal.is_double());
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EXPECT_EQ(decimal.to_double(), 3.5);
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EXPECT_EQ(decimal.to_string(), "3.5");
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}
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TEST(Numeric_decimal, construct_from_double_negative) {
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const double value{-7.25};
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const sourcemeta::core::Decimal decimal{value};
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EXPECT_TRUE(decimal.is_double());
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EXPECT_EQ(decimal.to_double(), -7.25);
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EXPECT_EQ(decimal.to_string(), "-7.25");
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}
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TEST(Numeric_decimal, construct_from_double_zero) {
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const double value{0.0};
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const sourcemeta::core::Decimal decimal{value};
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EXPECT_TRUE(decimal.is_double());
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EXPECT_TRUE(decimal.is_zero());
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EXPECT_EQ(decimal.to_double(), 0.0);
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}
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TEST(Numeric_decimal, construct_from_double_very_small) {
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const double value{0.125};
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const sourcemeta::core::Decimal decimal{value};
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EXPECT_TRUE(decimal.is_double());
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EXPECT_EQ(decimal.to_double(), 0.125);
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EXPECT_EQ(decimal.to_string(), "0.125");
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}
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TEST(Numeric_decimal, construct_from_double_roundtrip) {
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const double value{3.2};
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const sourcemeta::core::Decimal decimal{value};
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EXPECT_TRUE(decimal.is_double());
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const double roundtrip{decimal.to_double()};
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EXPECT_EQ(roundtrip, value);
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}
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TEST(Numeric_decimal, construct_from_float_roundtrip) {
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const float value{3.2f};
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const sourcemeta::core::Decimal decimal{value};
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EXPECT_TRUE(decimal.is_float());
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const float roundtrip{decimal.to_float()};
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EXPECT_EQ(roundtrip, value);
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}
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TEST(Numeric_decimal, construct_from_double_high_precision) {
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const double value{1.234567890123456};
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const sourcemeta::core::Decimal decimal{value};
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const double roundtrip{decimal.to_double()};
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EXPECT_EQ(roundtrip, value);
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}
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TEST(Numeric_decimal, construct_from_float_high_precision) {
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const float value{1.234567f};
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const sourcemeta::core::Decimal decimal{value};
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const float roundtrip{decimal.to_float()};
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EXPECT_EQ(roundtrip, value);
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}

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