[libc++][format] Fixes times before epoch.

The number of days should be rounded down, for both positive and negative times since epoch. The original code truncated, which is correct for positive values, but wrong for negative values. Depends on D138826 Reviewed By: #libc, ldionne Differential Revision: https://reviews.llvm.org/D154865
llvm · Jul 18, 2023 · b9f3d24 · b9f3d24
1 parent 1be4db7
commit b9f3d24
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Showing 4 changed files with 62 additions and 1 deletion.
diff --git a/libcxx/include/__chrono/convert_to_tm.h b/libcxx/include/__chrono/convert_to_tm.h
@@ -78,7 +78,7 @@ _LIBCPP_HIDE_FROM_ABI _Tm __convert_to_tm(const _Date& __date, chrono::weekday _
 
 template <class _Tm, class _Duration>
 _LIBCPP_HIDE_FROM_ABI _Tm __convert_to_tm(const chrono::sys_time<_Duration> __tp) {
-  chrono::sys_days __days = chrono::time_point_cast<chrono::days>(__tp);
+  chrono::sys_days __days = chrono::floor<chrono::days>(__tp);
   chrono::year_month_day __ymd{__days};
 
   _Tm __result = std::__convert_to_tm<_Tm>(chrono::year_month_day{__ymd}, chrono::weekday{__days});

diff --git a/libcxx/test/std/time/time.syn/formatter.file_time.pass.cpp b/libcxx/test/std/time/time.syn/formatter.file_time.pass.cpp
@@ -49,10 +49,30 @@ static void test_no_chrono_specs() {
   std::locale::global(std::locale(LOCALE_fr_FR_UTF_8));
 
   // Non localized output
+
+  // [time.syn]
+  //   using nanoseconds  = duration<signed integer type of at least 64 bits, nano>;
+  //   using microseconds = duration<signed integer type of at least 55 bits, micro>;
+  //   using milliseconds = duration<signed integer type of at least 45 bits, milli>;
+  //   using seconds      = duration<signed integer type of at least 35 bits>;
+  //   using minutes      = duration<signed integer type of at least 29 bits, ratio<  60>>;
+  //   using hours        = duration<signed integer type of at least 23 bits, ratio<3600>>;
+  check(SV("1425-08-04 22:06:56"), SV("{}"), file_seconds(-17'179'869'184s)); // Minimum value for 35 bits.
+  check(SV("1901-12-13 20:45:52"), SV("{}"), file_seconds(-2'147'483'648s));
+
+  check(SV("1969-12-31 00:00:00"), SV("{}"), file_seconds(-24h));
+  check(SV("1969-12-31 06:00:00"), SV("{}"), file_seconds(-18h));
+  check(SV("1969-12-31 12:00:00"), SV("{}"), file_seconds(-12h));
+  check(SV("1969-12-31 18:00:00"), SV("{}"), file_seconds(-6h));
+  check(SV("1969-12-31 23:59:59"), SV("{}"), file_seconds(-1s));
+
   check(SV("1970-01-01 00:00:00"), SV("{}"), file_seconds(0s));
   check(SV("2000-01-01 00:00:00"), SV("{}"), file_seconds(946'684'800s));
   check(SV("2000-01-01 01:02:03"), SV("{}"), file_seconds(946'688'523s));
 
+  check(SV("2038-01-19 03:14:07"), SV("{}"), file_seconds(2'147'483'647s));
+  check(SV("2514-05-30 01:53:03"), SV("{}"), file_seconds(17'179'869'183s)); // Maximum value for 35 bits.
+
   check(SV("2000-01-01 01:02:03.123"), SV("{}"), file_time<std::chrono::milliseconds>(946'688'523'123ms));
 
   std::locale::global(std::locale::classic());

diff --git a/libcxx/test/std/time/time.syn/formatter.local_time.pass.cpp b/libcxx/test/std/time/time.syn/formatter.local_time.pass.cpp
@@ -42,10 +42,31 @@ static void test_no_chrono_specs() {
   std::locale::global(std::locale(LOCALE_fr_FR_UTF_8));
 
   // Non localized output
+
+  // [time.syn]
+  //   using nanoseconds  = duration<signed integer type of at least 64 bits, nano>;
+  //   using microseconds = duration<signed integer type of at least 55 bits, micro>;
+  //   using milliseconds = duration<signed integer type of at least 45 bits, milli>;
+  //   using seconds      = duration<signed integer type of at least 35 bits>;
+  //   using minutes      = duration<signed integer type of at least 29 bits, ratio<  60>>;
+  //   using hours        = duration<signed integer type of at least 23 bits, ratio<3600>>;
+  check(
+      SV("1425-08-04 22:06:56"), SV("{}"), std::chrono::local_seconds(-17'179'869'184s)); // Minimum value for 35 bits.
+  check(SV("1901-12-13 20:45:52"), SV("{}"), std::chrono::local_seconds(-2'147'483'648s));
+
+  check(SV("1969-12-31 00:00:00"), SV("{}"), std::chrono::local_seconds(-24h));
+  check(SV("1969-12-31 06:00:00"), SV("{}"), std::chrono::local_seconds(-18h));
+  check(SV("1969-12-31 12:00:00"), SV("{}"), std::chrono::local_seconds(-12h));
+  check(SV("1969-12-31 18:00:00"), SV("{}"), std::chrono::local_seconds(-6h));
+  check(SV("1969-12-31 23:59:59"), SV("{}"), std::chrono::local_seconds(-1s));
+
   check(SV("1970-01-01 00:00:00"), SV("{}"), std::chrono::local_seconds(0s));
   check(SV("2000-01-01 00:00:00"), SV("{}"), std::chrono::local_seconds(946'684'800s));
   check(SV("2000-01-01 01:02:03"), SV("{}"), std::chrono::local_seconds(946'688'523s));
 
+  check(SV("2038-01-19 03:14:07"), SV("{}"), std::chrono::local_seconds(2'147'483'647s));
+  check(SV("2514-05-30 01:53:03"), SV("{}"), std::chrono::local_seconds(17'179'869'183s)); // Maximum value for 35 bits.
+
   check(SV("2000-01-01 01:02:03.123"), SV("{}"), std::chrono::local_time<std::chrono::milliseconds>(946'688'523'123ms));
 
   std::locale::global(std::locale::classic());

diff --git a/libcxx/test/std/time/time.syn/formatter.sys_time.pass.cpp b/libcxx/test/std/time/time.syn/formatter.sys_time.pass.cpp
@@ -42,10 +42,30 @@ static void test_no_chrono_specs() {
   std::locale::global(std::locale(LOCALE_fr_FR_UTF_8));
 
   // Non localized output
+
+  // [time.syn]
+  //   using nanoseconds  = duration<signed integer type of at least 64 bits, nano>;
+  //   using microseconds = duration<signed integer type of at least 55 bits, micro>;
+  //   using milliseconds = duration<signed integer type of at least 45 bits, milli>;
+  //   using seconds      = duration<signed integer type of at least 35 bits>;
+  //   using minutes      = duration<signed integer type of at least 29 bits, ratio<  60>>;
+  //   using hours        = duration<signed integer type of at least 23 bits, ratio<3600>>;
+  check(SV("1425-08-04 22:06:56"), SV("{}"), std::chrono::sys_seconds(-17'179'869'184s)); // Minimum value for 35 bits.
+  check(SV("1901-12-13 20:45:52"), SV("{}"), std::chrono::sys_seconds(-2'147'483'648s));
+
+  check(SV("1969-12-31 00:00:00"), SV("{}"), std::chrono::sys_seconds(-24h));
+  check(SV("1969-12-31 06:00:00"), SV("{}"), std::chrono::sys_seconds(-18h));
+  check(SV("1969-12-31 12:00:00"), SV("{}"), std::chrono::sys_seconds(-12h));
+  check(SV("1969-12-31 18:00:00"), SV("{}"), std::chrono::sys_seconds(-6h));
+  check(SV("1969-12-31 23:59:59"), SV("{}"), std::chrono::sys_seconds(-1s));
+
   check(SV("1970-01-01 00:00:00"), SV("{}"), std::chrono::sys_seconds(0s));
   check(SV("2000-01-01 00:00:00"), SV("{}"), std::chrono::sys_seconds(946'684'800s));
   check(SV("2000-01-01 01:02:03"), SV("{}"), std::chrono::sys_seconds(946'688'523s));
 
+  check(SV("2038-01-19 03:14:07"), SV("{}"), std::chrono::sys_seconds(2'147'483'647s));
+  check(SV("2514-05-30 01:53:03"), SV("{}"), std::chrono::sys_seconds(17'179'869'183s)); // Maximum value for 35 bits.
+
   check(SV("2000-01-01 01:02:03.123"), SV("{}"), std::chrono::sys_time<std::chrono::milliseconds>(946'688'523'123ms));
 
   std::locale::global(std::locale::classic());