libstdc++: Format empty chrono-spec for the sys_info and local_info directly.

This patch change implementation of the formatters for sys_info and local_info,
so they no longer delegate to operator<< for ostream in case of empty spec.
As this types may be only formatted with chrono-spec containing only %%, %t, %n
specifiers and fill characters, we use a separate __formatter_chrono_info formatter.

For empty chron-spec __formatter_chrono_info formats sys_info using format_to call
with format specifier extracted from corresponding operator<<, that now delegates
to format with empty spec. For local_info we replicate functionality of the operator<<.
The alignment and padding is handled using an _Padding_sink.

For non-empty spec, we delegate to __formatter_chrono::_M_format. As non-of the
format specifiers depends on the formatted object, we pass chrono::day to avoid
triggering additional specializations.

libstdc++-v3/ChangeLog:

	* include/bits/chrono_io.h (__format::__formatter_chrono_info)
	[_GLIBCXX_USE_CXX11_ABI || ! _GLIBCXX_USE_DUAL_ABI]: Define.
	(std::formatter<chrono::sys_info, _CharT>)
	(std::formatter<chrono::local_inf, _CharT>): Delegate to
	__format::__formatter_chrono_info.
	(std::operator<<(basic_ostream<_CharT, _Traits>& const sys_info&)):
	Use format on sys_info with empty format spec.

Reviewed-by: Jonathan Wakely <jwakely@redhat.com>
Signed-off-by: Tomasz Kamiński <tkaminsk@redhat.com>

0 files changed, 0 insertions, 0 deletions