https://gcc.gnu.org/g:e52f71b6dd888f0d5548d9f5bd139601dbafb3be
commit r15-9631-ge52f71b6dd888f0d5548d9f5bd139601dbafb3be
Author: Tomasz Kamiński <tkami...@redhat.com>
Date: Mon May 5 16:32:58 2025 +0200
libstdc++: Fix width computation for the chrono formatting [PR120114]
Use `__unicode::_field_width` to compute the field width of the output when
writting
the formatted output for std::chrono::types. This applies both to
characters copied
from format string, and one produced by localized formatting.
We also use _Str_sink::view() instead of get(), which avoids copying the
content of
the buffer to std::string in case of small output.
PR libstdc++/120114
libstdc++-v3/ChangeLog:
* include/bits/chrono_io.h (__formatter_chrono::_M_format): Use
__field_width.
* testsuite/std/time/format/pr120114.cc: New test.
Reviewed-by: Jonathan Wakely <jwak...@redhat.com>
Signed-off-by: Tomasz Kamiński <tkami...@redhat.com>
(cherry picked from commit 52f6ab55051ff43fd1b40ff06d9501043f8ba844)
Diff:
---
libstdc++-v3/include/bits/chrono_io.h | 10 +-
libstdc++-v3/testsuite/std/time/format/pr120114.cc | 125 +++++++++++++++++++++
2 files changed, 133 insertions(+), 2 deletions(-)
diff --git a/libstdc++-v3/include/bits/chrono_io.h
b/libstdc++-v3/include/bits/chrono_io.h
index b7f6f5f49e5e..f5aa8a3e18af 100644
--- a/libstdc++-v3/include/bits/chrono_io.h
+++ b/libstdc++-v3/include/bits/chrono_io.h
@@ -705,8 +705,14 @@ namespace __format
if (__write_direct)
return __out;
- auto __str = std::move(__sink).get();
- return __format::__write_padded_as_spec(__str, __str.size(),
+ auto __span = __sink.view();
+ __string_view __str(__span.data(), __span.size());
+ size_t __width;
+ if constexpr (__unicode::__literal_encoding_is_unicode<_CharT>())
+ __width = __unicode::__field_width(__str);
+ else
+ __width = __str.size();
+ return __format::__write_padded_as_spec(__str, __width,
__fc, _M_spec);
}
diff --git a/libstdc++-v3/testsuite/std/time/format/pr120114.cc
b/libstdc++-v3/testsuite/std/time/format/pr120114.cc
new file mode 100644
index 000000000000..c630bb35a9d0
--- /dev/null
+++ b/libstdc++-v3/testsuite/std/time/format/pr120114.cc
@@ -0,0 +1,125 @@
+// { dg-do run { target c++23 } }
+// { dg-options "-fexec-charset=UTF-8" }
+// { dg-timeout-factor 2 }
+
+#include <algorithm>
+#include <chrono>
+#include <testsuite_hooks.h>
+
+#define WIDEN_(C, S) ::std::__format::_Widen<C>(S, L##S)
+#define WIDEN(S) WIDEN_(_CharT, S)
+
+template<typename _CharT>
+void
+test_from_format_string()
+{
+ std::basic_string<_CharT> res;
+ using namespace std::chrono_literals;
+ auto date = 2025y/std::chrono::May/05d;
+
+ res = std::format(WIDEN("{:+<13%F\U0001f921}"), date);
+ VERIFY( res == WIDEN("2025-05-05\U0001f921+") );
+
+ res = std::format(WIDEN("{:->15%F\U0001f921}"), date);
+ VERIFY( res == WIDEN("---2025-05-05\U0001f921") );
+
+ res = std::format(WIDEN("{:=^20%F\U0001f921}"), date);
+ VERIFY( res == WIDEN("====2025-05-05\U0001f921====") );
+}
+
+template<typename _CharT>
+void
+test_formatted_value()
+{
+ // Custom time_put facet which returns Ideographic Telegraph Symbol
+ // for given month for Om.
+ struct TimePut : std::time_put<_CharT>
+ {
+ using iter_type = std::time_put<_CharT>::iter_type;
+ using char_type = std::time_put<_CharT>::char_type;
+
+ iter_type
+ do_put(iter_type out, std::ios_base& io, char_type fill, const tm* t,
+ char format, char modifier) const override
+ {
+ if (format != 'm' && modifier != 'm')
+ return std::time_put<_CharT>::do_put(out, io, fill, t, format,
modifier);
+ std::basic_string_view<_CharT> str;
+ switch (t->tm_mon)
+ {
+ case 0:
+ str = WIDEN("\u32C0");
+ break;
+ case 1:
+ str = WIDEN("\u32C1");
+ break;
+ case 2:
+ str = WIDEN("\u32C2");
+ break;
+ case 3:
+ str = WIDEN("\u32C3");
+ break;
+ case 4:
+ str = WIDEN("\u32C4");
+ break;
+ case 5:
+ str = WIDEN("\u32C5");
+ break;
+ case 6:
+ str = WIDEN("\u32C6");
+ break;
+ case 7:
+ str = WIDEN("\u32C7");
+ break;
+ case 8:
+ str = WIDEN("\u32C8");
+ break;
+ case 9:
+ str = WIDEN("\u32C9");
+ break;
+ case 10:
+ str = WIDEN("\u32CA");
+ break;
+ case 11:
+ str = WIDEN("\u32CB");
+ break;
+ };
+ return std::copy(str.begin(), str.end(), out);
+ }
+ };
+ const std::locale loc(std::locale::classic(), new TimePut);
+
+ std::basic_string<_CharT> res;
+
+ res = std::format(loc, WIDEN("{:<1L%Om}"), std::chrono::January);
+ VERIFY( res == WIDEN("\u32C0") );
+
+ res = std::format(loc, WIDEN("{:>2L%Om}"), std::chrono::February);
+ VERIFY( res == WIDEN("\u32C1") );
+
+ res = std::format(loc, WIDEN("{:<3L%Om}"), std::chrono::March);
+ VERIFY( res == WIDEN("\u32C2 ") );
+
+ res = std::format(loc, WIDEN("{:^4L%Om}"), std::chrono::April);
+ VERIFY( res == WIDEN(" \u32C3 ") );
+
+ res = std::format(loc, WIDEN("{:>5L%Om}"), std::chrono::May);
+ VERIFY( res == WIDEN(" \u32C4") );
+
+ res = std::format(loc, WIDEN("{:+<6L%Om}"), std::chrono::June);
+ VERIFY( res == WIDEN("\u32C5++++") );
+
+ res = std::format(loc, WIDEN("{:=^7L%Om}"), std::chrono::July);
+ VERIFY( res == WIDEN("==\u32C6===") );
+
+ res = std::format(loc, WIDEN("{:->8L%Om}"), std::chrono::August);
+ VERIFY( res == WIDEN("------\u32C7") );
+}
+
+int main()
+{
+ test_from_format_string<char>();
+ test_from_format_string<wchar_t>();
+ test_formatted_value<char>();
+ test_formatted_value<wchar_t>();
+}
