Tested aarch64-linux. Pushed to trunk.
Backport to gcc-13 would be good too, I think.
-- >8 --
Currently trying to use std::format with certain specializations of
std::chrono::time_point is ill-formed, due to one member function of the
__formatter_chrono type which tries to write a time_point to an ostream.
For sys_time<floating-point> or sys_time with a period greater than days
there is no operator<< that can be used.
That operator<< is only needed when using an empty chrono-specs in the
format string, like "{}", but the ill-formed expression gives an error
even if not actually used. This means it's not possible to format some
other specializations of chrono::time_point, even when using a non-empty
chrono-specs.
This fixes it by avoiding using 'os << t' for all chrono::time_point
specializations, and instead using std::format("{:L%F %T}", t). So that
we continue to reject std::format("{}", sys_time{1.0s}) a check for
empty chrono-specs is added to the formatter<sys_time<D>, C>
specialization.
While testing this I noticed that the output for %S with a
floating-point duration was incorrect, as the subseconds part was being
appended to the seconds without a decimal point, and without the correct
number of leading zeros.
libstdc++-v3/ChangeLog:
PR libstdc++/113500
* include/bits/chrono_io.h (__formatter_chrono::_M_S): Fix
printing of subseconds with floating-point rep.
(__formatter_chrono::_M_format_to_ostream): Do not write
time_point specializations directly to the ostream.
(formatter<chrono::sys_time<D>, C>::parse): Do not allow an
empty chrono-spec if the type fails to meet the constraints for
writing to an ostream with operator<<.
* testsuite/std/time/clock/file/io.cc: Check formatting
non-integral times with empty chrono-specs.
* testsuite/std/time/clock/gps/io.cc: Likewise.
* testsuite/std/time/clock/utc/io.cc: Likewise.
* testsuite/std/time/hh_mm_ss/io.cc: Likewise.
---
libstdc++-v3/include/bits/chrono_io.h | 71 +++++++++++++------
.../testsuite/std/time/clock/file/io.cc | 17 +++++
.../testsuite/std/time/clock/gps/io.cc | 27 +++++++
.../testsuite/std/time/clock/utc/io.cc | 4 ++
.../testsuite/std/time/hh_mm_ss/io.cc | 28 +++++++-
5 files changed, 124 insertions(+), 23 deletions(-)
diff --git a/libstdc++-v3/include/bits/chrono_io.h
b/libstdc++-v3/include/bits/chrono_io.h
index 7b5876b24e6..82f2d39ec44 100644
--- a/libstdc++-v3/include/bits/chrono_io.h
+++ b/libstdc++-v3/include/bits/chrono_io.h
@@ -681,6 +681,7 @@ namespace __format
return __fc.locale();
}
+ // Format for empty chrono-specs, e.g. "{}" (C++20 [time.format] p6).
// TODO: consider moving body of every operator<< into this function
// and use std::format("{}", t) to implement those operators. That
// would avoid std::format("{}", t) calling operator<< which calls
@@ -702,6 +703,22 @@ namespace __format
if constexpr (__is_specialization_of<_Tp, __utc_leap_second>)
__os << __t._M_date << ' ' << __t._M_time;
+ else if constexpr (chrono::__is_time_point_v<_Tp>)
+ {
+ // Need to be careful here because not all specializations
+ // of chrono::sys_time can be written to an ostream.
+ // For the specializations of time_point that can be
+ // formatted with an empty chrono-specs, either it's a
+ // sys_time with period greater or equal to days:
+ if constexpr (is_convertible_v<_Tp, chrono::sys_days>)
+ __os << _S_date(__t);
+ else // Or it's formatted as "{:L%F %T}":
+ {
+ auto __days = chrono::floor<chrono::days>(__t);
+ __os << chrono::year_month_day(__days) << ' '
+ << chrono::hh_mm_ss(__t - __days);
+ }
+ }
else
{
if constexpr (chrono::__is_duration_v<_Tp>)
@@ -1122,39 +1139,43 @@ namespace __format
'S', 'O');
}
- __out = __format::__write(std::move(__out),
- _S_two_digits(__hms.seconds().count()));
- if constexpr (__hms.fractional_width != 0)
+ if constexpr (__hms.fractional_width == 0)
+ __out = __format::__write(std::move(__out),
+ _S_two_digits(__hms.seconds().count()));
+ else
{
locale __loc = _M_locale(__ctx);
+ auto __s = __hms.seconds();
auto __ss = __hms.subseconds();
using rep = typename decltype(__ss)::rep;
if constexpr (is_floating_point_v<rep>)
{
+ chrono::duration<rep> __fs = __s + __ss;
__out = std::format_to(std::move(__out), __loc,
- _GLIBCXX_WIDEN("{:.{}Lg}"),
- __ss.count(),
- __hms.fractional_width);
- }
- else if constexpr (is_integral_v<rep>)
- {
- const auto& __np
- = use_facet<numpunct<_CharT>>(__loc);
- __out = std::format_to(std::move(__out),
- _GLIBCXX_WIDEN("{}{:0{}}"),
- __np.decimal_point(),
- __ss.count(),
+ _GLIBCXX_WIDEN("{:#0{}.{}Lf}"),
+ __fs.count(),
+ 3 + __hms.fractional_width,
__hms.fractional_width);
}
else
{
const auto& __np
= use_facet<numpunct<_CharT>>(__loc);
+ __out = __format::__write(std::move(__out),
+ _S_two_digits(__s.count()));
*__out++ = __np.decimal_point();
- auto __str = std::format(_S_empty_spec, __ss.count());
- __out = std::format_to(_GLIBCXX_WIDEN("{:0>{}s}"),
- __str,
- __hms.fractional_width);
+ if constexpr (is_integral_v<rep>)
+ __out = std::format_to(std::move(__out),
+ _GLIBCXX_WIDEN("{:0{}}"),
+ __ss.count(),
+ __hms.fractional_width);
+ else
+ {
+ auto __str = std::format(_S_empty_spec, __ss.count());
+ __out = std::format_to(_GLIBCXX_WIDEN("{:0>{}s}"),
+ __str,
+ __hms.fractional_width);
+ }
}
}
return __out;
@@ -1911,7 +1932,13 @@ namespace __format
template<typename _ParseContext>
constexpr typename _ParseContext::iterator
parse(_ParseContext& __pc)
- { return _M_f._M_parse(__pc, __format::_ZonedDateTime); }
+ {
+ auto __next = _M_f._M_parse(__pc, __format::_ZonedDateTime);
+ if constexpr (!__stream_insertable)
+ if (_M_f._M_spec._M_chrono_specs.empty())
+ __format::__invalid_chrono_spec(); // chrono-specs can't be empty
+ return __next;
+ }
template<typename _FormatContext>
typename _FormatContext::iterator
@@ -1920,6 +1947,10 @@ namespace __format
{ return _M_f._M_format(__t, __fc); }
private:
+ static constexpr bool __stream_insertable
+ = requires (basic_ostream<_CharT>& __os,
+ chrono::sys_time<_Duration> __t) { __os << __t; };
+
__format::__formatter_chrono<_CharT> _M_f;
};
diff --git a/libstdc++-v3/testsuite/std/time/clock/file/io.cc
b/libstdc++-v3/testsuite/std/time/clock/file/io.cc
index 39eb0dbcf51..3eee6bf5cc2 100644
--- a/libstdc++-v3/testsuite/std/time/clock/file/io.cc
+++ b/libstdc++-v3/testsuite/std/time/clock/file/io.cc
@@ -17,6 +17,23 @@ test_ostream()
VERIFY( ss1.str() == ss2.str() );
}
+void
+test_format()
+{
+ using namespace std::chrono;
+ auto t = file_clock::now();
+
+ auto s = std::format("{}", t);
+ std::ostringstream ss;
+ ss << t;
+ VERIFY( s == ss.str() );
+
+ // PR libstdc++/113500
+ auto ft = clock_cast<file_clock>(sys_days(2024y/January/21)) + 0ms + 2.5s;
+ s = std::format("{}", ft);
+ VERIFY( s == "2024-01-17 00:00:02.500");
+}
+
void
test_parse()
{
diff --git a/libstdc++-v3/testsuite/std/time/clock/gps/io.cc
b/libstdc++-v3/testsuite/std/time/clock/gps/io.cc
index 6f4544fcd97..5d15713c69d 100644
--- a/libstdc++-v3/testsuite/std/time/clock/gps/io.cc
+++ b/libstdc++-v3/testsuite/std/time/clock/gps/io.cc
@@ -3,6 +3,7 @@
#include <chrono>
#include <format>
+#include <sstream>
#include <testsuite_hooks.h>
void
@@ -16,6 +17,32 @@ test_ostream()
auto s = format("{0:%F %T %Z} == {1:%F %T %Z}", st, gt);
VERIFY( s == "2000-01-01 00:00:00 UTC == 2000-01-01 00:00:13 GPS" );
+
+ std::ostringstream ss;
+ ss << gt;
+ VERIFY( ss.str() == "2000-01-01 00:00:13" );
+
+ gps_time<duration<float>> gtf = gt;
+ ss.str("");
+ ss.clear();
+ ss << (gps_time<duration<long double>>(gt) + 20ms);
+ VERIFY( ss.str() == "2000-01-01 00:00:13.020" );
+}
+
+void
+test_format()
+{
+ using std::format;
+ using namespace std::chrono;
+
+ auto st = sys_days{2000y/January/1};
+ auto gt = clock_cast<gps_clock>(st);
+ auto s = std::format("{}", gt);
+ VERIFY( s == "2000-01-01 00:00:13" );
+
+ // PR libstdc++/113500
+ s = std::format("{}", gt + 150ms + 10.5s);
+ VERIFY( s == "2000-01-01 00:00:35.650" );
}
void
diff --git a/libstdc++-v3/testsuite/std/time/clock/utc/io.cc
b/libstdc++-v3/testsuite/std/time/clock/utc/io.cc
index 58e358f3dbf..55c53dc4057 100644
--- a/libstdc++-v3/testsuite/std/time/clock/utc/io.cc
+++ b/libstdc++-v3/testsuite/std/time/clock/utc/io.cc
@@ -112,6 +112,10 @@ test_format()
s = std::format("{:%T}", leap + 1s);
VERIFY( s == "00:00:00" );
+
+ // PR libstdc++/113500
+ s = std::format("{}", leap + 100ms + 2.5s);
+ VERIFY( s == "2017-01-01 00:00:01.600");
}
void
diff --git a/libstdc++-v3/testsuite/std/time/hh_mm_ss/io.cc
b/libstdc++-v3/testsuite/std/time/hh_mm_ss/io.cc
index 8eb80422e6e..d651dfbcdc8 100644
--- a/libstdc++-v3/testsuite/std/time/hh_mm_ss/io.cc
+++ b/libstdc++-v3/testsuite/std/time/hh_mm_ss/io.cc
@@ -35,9 +35,31 @@ test_ostream()
VERIFY( out.str() == "18:15:45.123" );
}
- ostringstream out;
- out << hh_mm_ss{65745s};
- VERIFY( out.str() == "18:15:45" );
+ {
+ ostringstream out;
+ out << hh_mm_ss{65745s};
+ VERIFY( out.str() == "18:15:45" );
+ }
+
+ {
+ ostringstream out;
+ out << hh_mm_ss{0.020s};
+ // hh_mm_ss<duration<long double>>::fractional_width == 0 so no subseconds:
+ VERIFY( out.str() == "00:00:00" );
+ }
+
+ {
+ ostringstream out;
+ out << hh_mm_ss<std::chrono::duration<long double, std::nano>>{0.020s};
+ // hh_mm_ss<duration<long double, nano>>::fractional_width == 9:
+ VERIFY( out.str() == "00:00:00.020000000" );
+ }
+
+ {
+ ostringstream out;
+ out << hh_mm_ss{65745s + 20ms};
+ VERIFY( out.str() == "18:15:45.020" );
+ }
}
void
--
2.43.0
