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Implement isnan

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This commit is contained in:
Victor Zverovich
2022-03-14 20:37:46 -07:00
parent a204b8dde7
commit ed18ca3eae
3 changed files with 28 additions and 24 deletions
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9
include/fmt/chrono.h
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@@ -1388,15 +1388,6 @@ struct chrono_format_checker : null_chrono_spec_handler<chrono_format_checker> {
FMT_CONSTEXPR void on_duration_unit() {} FMT_CONSTEXPR void on_duration_unit() {}
}; };
template <typename T, FMT_ENABLE_IF(std::is_integral<T>::value)>
inline bool isnan(T) {
return false;
}
template <typename T, FMT_ENABLE_IF(std::is_floating_point<T>::value)>
inline bool isnan(T value) {
return std::isnan(value);
}
template <typename T, FMT_ENABLE_IF(std::is_integral<T>::value)> template <typename T, FMT_ENABLE_IF(std::is_integral<T>::value)>
inline bool isfinite(T) { inline bool isfinite(T) {
return true; return true;

22
include/fmt/format.h
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@@ -1905,11 +1905,11 @@ FMT_CONSTEXPR auto write(OutputIt out, const Char* s,
} }
template <typename Char, typename OutputIt> template <typename Char, typename OutputIt>
FMT_CONSTEXPR20 auto write_nonfinite(OutputIt out, bool isinf, FMT_CONSTEXPR20 auto write_nonfinite(OutputIt out, bool isnan,
basic_format_specs<Char> specs, basic_format_specs<Char> specs,
const float_specs& fspecs) -> OutputIt { const float_specs& fspecs) -> OutputIt {
auto str = auto str =
isinf ? (fspecs.upper ? "INF" : "inf") : (fspecs.upper ? "NAN" : "nan"); isnan ? (fspecs.upper ? "NAN" : "nan") : (fspecs.upper ? "INF" : "inf");
constexpr size_t str_size = 3; constexpr size_t str_size = 3;
auto sign = fspecs.sign; auto sign = fspecs.sign;
auto size = str_size + (sign ? 1 : 0); auto size = str_size + (sign ? 1 : 0);
@@ -2182,16 +2182,8 @@ constexpr bool isfinite(T value) {
return value - value == 0; // std::isfinite doesn't support __float128. return value - value == 0; // std::isfinite doesn't support __float128.
} }
template <typename T, FMT_ENABLE_IF(std::is_floating_point<T>::value && template <typename T> constexpr bool isnan(T value) {
!is_float128<T>::value)> return value != value; // std::isnan doesn't support __float128.
FMT_CONSTEXPR20 bool isinf(T value) {
if (is_constant_evaluated()) return !isfinite(value) && value == value;
return std::isinf(value);
}
template <typename T, FMT_ENABLE_IF(is_float128<T>::value)>
constexpr bool isinf(T value) {
// std::isinf doesn't support __float128.
return !isfinite(value) && value == value;
} }
template <typename T, FMT_ENABLE_IF(std::is_floating_point<T>::value)> template <typename T, FMT_ENABLE_IF(std::is_floating_point<T>::value)>
@@ -2200,7 +2192,7 @@ FMT_INLINE FMT_CONSTEXPR bool signbit(T value) {
#ifdef __cpp_if_constexpr #ifdef __cpp_if_constexpr
if constexpr (std::numeric_limits<double>::is_iec559) { if constexpr (std::numeric_limits<double>::is_iec559) {
auto bits = detail::bit_cast<uint64_t>(static_cast<double>(value)); auto bits = detail::bit_cast<uint64_t>(static_cast<double>(value));
return (bits & (uint64_t(1) << (num_bits<uint64_t>() - 1))) != 0; return (bits >> (num_bits<uint64_t>() - 1)) != 0;
} }
#endif #endif
} }
@@ -2223,7 +2215,7 @@ FMT_CONSTEXPR20 auto write(OutputIt out, T value,
} }
if (!detail::isfinite(value)) if (!detail::isfinite(value))
return write_nonfinite(out, detail::isinf(value), specs, fspecs); return write_nonfinite(out, detail::isnan(value), specs, fspecs);
if (specs.align == align::numeric && fspecs.sign) { if (specs.align == align::numeric && fspecs.sign) {
auto it = reserve(out, 1); auto it = reserve(out, 1);
@@ -2279,7 +2271,7 @@ FMT_CONSTEXPR20 auto write(OutputIt out, T value) -> OutputIt {
constexpr auto specs = basic_format_specs<Char>(); constexpr auto specs = basic_format_specs<Char>();
uint mask = exponent_mask<floaty>(); uint mask = exponent_mask<floaty>();
if ((bits & mask) == mask) if ((bits & mask) == mask)
return write_nonfinite(out, std::isinf(value), specs, fspecs); return write_nonfinite(out, std::isnan(value), specs, fspecs);
auto dec = dragonbox::to_decimal(static_cast<floaty>(value)); auto dec = dragonbox::to_decimal(static_cast<floaty>(value));
return write_float(out, dec, specs, fspecs, {}); return write_float(out, dec, specs, fspecs, {});

21
test/format-test.cc
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@@ -87,6 +87,27 @@ TEST(float_test, isfinite) {
#endif #endif
} }
template <typename Float> void check_isnan() {
using fmt::detail::isnan;
EXPECT_FALSE(isnan(Float(0.0)));
EXPECT_FALSE(isnan(Float(42.0)));
EXPECT_FALSE(isnan(Float(-42.0)));
EXPECT_FALSE(isnan(Float(fmt::detail::max_value<double>())));
// Use double because std::numeric_limits is broken for __float128.
using limits = std::numeric_limits<double>;
EXPECT_FALSE(isnan(Float(limits::infinity())));
EXPECT_FALSE(isnan(Float(-limits::infinity())));
EXPECT_TRUE(isnan(Float(limits::quiet_NaN())));
EXPECT_TRUE(isnan(Float(-limits::quiet_NaN())));
}
TEST(float_test, isnan) {
check_isnan<double>();
#ifdef __SIZEOF_FLOAT128__
check_isnan<fmt::detail::float128>();
#endif
}
struct uint32_pair { struct uint32_pair {
uint32_t u[2]; uint32_t u[2];
}; };