Implement c++20 std::chrono::duration subsecond formatting (#2623)

* Add support for subsecond printing for std::chrono::duration according to the c++20 standard

* Remove assert test that overflows intmax_t

* * Hopefully fix int64_t to int32_t conversion errors.
* Allow proper Duration::rep type to propagate via template argument deduction

* * Hopefully fix int64_t to int32_t conversion errors.
* Allow proper Duration::rep type to propagate via template argument deduction

* Fix sign conversion (-Wsign-conversion) warning treated as error in num_digits()

* Format chrono.h with clang-format

* Remove extra forward slash in doxygen style comment

Co-authored-by: Victor Zverovich <victor.zverovich@gmail.com>

* Apply all suggestions from GitHub, except for replacing the utility subsecond_helper class with a function

* * Move logic of handling subseconds from utility class to function with name write_fractional_seconds()
* Revert write(Rep value, int width) function to previous state

* Fix -Wshadow warning

* Remove unsued get_subseconds() function, its logic has been moved to write_fractional_seconds()

* Change comment from lowercase int to uppercase Int

* Simplify test check

* Integrate suggested changes

* Remove static from detail functions, they are no longer member functions of a class and static is unnecessary.
* Change comment from "amount" to "number"

Co-authored-by: Victor Zverovich <victor.zverovich@gmail.com>
This commit is contained in:
matrackif
2021-12-09 15:45:13 +01:00
committed by GitHub
parent 9d5b9defde
commit 0bbc9708f9
2 changed files with 111 additions and 34 deletions

View File

@@ -543,15 +543,12 @@ TEST(chrono_test, negative_durations) {
}
TEST(chrono_test, special_durations) {
EXPECT_EQ(
"40.",
fmt::format("{:%S}", std::chrono::duration<double>(1e20)).substr(0, 3));
auto value = fmt::format("{:%S}", std::chrono::duration<double>(1e20));
EXPECT_EQ(value, "40");
auto nan = std::numeric_limits<double>::quiet_NaN();
EXPECT_EQ(
"nan nan nan nan nan:nan nan",
fmt::format("{:%I %H %M %S %R %r}", std::chrono::duration<double>(nan)));
(void)fmt::format("{:%S}",
std::chrono::duration<float, std::atto>(1.79400457e+31f));
EXPECT_EQ(fmt::format("{}", std::chrono::duration<float, std::exa>(1)),
"1Es");
EXPECT_EQ(fmt::format("{}", std::chrono::duration<float, std::atto>(1)),
@@ -585,4 +582,44 @@ TEST(chrono_test, weekday) {
}
}
TEST(chrono_test, cpp20_duration_subsecond_support) {
using attoseconds = std::chrono::duration<long long, std::atto>;
// Check that 18 digits of subsecond precision are supported.
EXPECT_EQ(fmt::format("{:%S}", attoseconds{999999999999999999}),
"00.999999999999999999");
EXPECT_EQ(fmt::format("{:%S}", attoseconds{673231113420148734}),
"00.673231113420148734");
EXPECT_EQ(fmt::format("{:%S}", attoseconds{-673231113420148734}),
"-00.673231113420148734");
EXPECT_EQ(fmt::format("{:%S}", std::chrono::nanoseconds{13420148734}),
"13.420148734");
EXPECT_EQ(fmt::format("{:%S}", std::chrono::nanoseconds{-13420148734}),
"-13.420148734");
EXPECT_EQ(fmt::format("{:%S}", std::chrono::milliseconds{1234}), "01.234");
{
// Check that {:%H:%M:%S} is equivalent to {:%T}.
auto dur = std::chrono::milliseconds{3601234};
auto formatted_dur = fmt::format("{:%T}", dur);
EXPECT_EQ(formatted_dur, "01:00:01.234");
EXPECT_EQ(fmt::format("{:%H:%M:%S}", dur), formatted_dur);
}
using nanoseconds_dbl = std::chrono::duration<double, std::nano>;
EXPECT_EQ(fmt::format("{:%S}", nanoseconds_dbl{-123456789}), "-00.123456789");
EXPECT_EQ(fmt::format("{:%S}", nanoseconds_dbl{9123456789}), "09.123456789");
// Verify that only the seconds part is extracted and printed.
EXPECT_EQ(fmt::format("{:%S}", nanoseconds_dbl{99123456789}), "39.123456789");
EXPECT_EQ(fmt::format("{:%S}", nanoseconds_dbl{99123000000}), "39.123000000");
{
// Now the hour is printed, and we also test if negative doubles work.
auto dur = nanoseconds_dbl{-99123456789};
auto formatted_dur = fmt::format("{:%T}", dur);
EXPECT_EQ(formatted_dur, "-00:01:39.123456789");
EXPECT_EQ(fmt::format("{:%H:%M:%S}", dur), formatted_dur);
}
// Check that durations with precision greater than std::chrono::seconds have
// fixed precision, and print zeros even if there is no fractional part.
EXPECT_EQ(fmt::format("{:%S}", std::chrono::microseconds{7000000}),
"07.000000");
}
#endif // FMT_STATIC_THOUSANDS_SEPARATOR