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[libc++][chrono] Fixes format output of negative values. #89408

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Merged
merged 2 commits into from
Apr 23, 2024
Merged

[libc++][chrono] Fixes format output of negative values. #89408

merged 2 commits into from
Apr 23, 2024

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@mordante mordante commented Apr 19, 2024 •
edited by ldionne
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When trying to express a time before the epoch (e.g. "one nanosecond before 00:01:40 on 1900-01-01")
the date would be shown as:

1900-01-01 00:01:39.-00000001

After this patch, that time would be correctly shown as:

1900-01-01 00:01:39.999999999

@mordante mordante requested a review from a team as a code owner April 19, 2024 16:09
@llvmbot llvmbot added the libc++ libc++ C++ Standard Library. Not GNU libstdc++. Not libc++abi. label Apr 19, 2024
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llvmbot commented Apr 19, 2024

@llvm/pr-subscribers-libcxx

Author: Mark de Wever (mordante)

Changes

The negative values were shown as

1900-01-01 00:01:39.-00000001

after the changes they are shown as

1900-01-01 00:01:39.999999999

Full diff: https://github.com/llvm/llvm-project/pull/89408.diff

4 Files Affected:

  • (modified) libcxx/include/__chrono/formatter.h (+3)
  • (modified) libcxx/test/std/time/time.clock/time.clock.file/ostream.pass.cpp (+54)
  • (modified) libcxx/test/std/time/time.clock/time.clock.local/ostream.pass.cpp (+54)
  • (modified) libcxx/test/std/time/time.clock/time.clock.system/sys_time.ostream.pass.cpp (+54)
diff --git a/libcxx/include/__chrono/formatter.h b/libcxx/include/__chrono/formatter.h
index 226fccbee6d133..058e9ac97bc941 100644
--- a/libcxx/include/__chrono/formatter.h
+++ b/libcxx/include/__chrono/formatter.h
@@ -88,6 +88,9 @@ __format_sub_seconds(basic_stringstream<_CharT>& __sstr, const chrono::duration<
   using __duration = chrono::duration<_Rep, _Period>;
 
   auto __fraction = __value - chrono::duration_cast<chrono::seconds>(__value);
+  // Converts a negative fraction to its positive value.
+  if (__value < chrono::seconds{0})
+    __fraction += chrono::seconds{1};
   if constexpr (chrono::treat_as_floating_point_v<_Rep>)
     // When the floating-point value has digits itself they are ignored based
     // on the wording in [tab:time.format.spec]
diff --git a/libcxx/test/std/time/time.clock/time.clock.file/ostream.pass.cpp b/libcxx/test/std/time/time.clock/time.clock.file/ostream.pass.cpp
index 18a4506b91566b..99d56002e9c391 100644
--- a/libcxx/test/std/time/time.clock/time.clock.file/ostream.pass.cpp
+++ b/libcxx/test/std/time/time.clock/time.clock.file/ostream.pass.cpp
@@ -71,6 +71,24 @@ template <class CharT>
 static void test_c() {
   using namespace std::literals::chrono_literals;
 
+  assert(stream_c_locale<CharT>(std::chrono::file_time<std::chrono::nanoseconds>{-946'688'523'123'456'789ns}) ==
+         SV("1940-01-01 22:57:56.876543211"));
+
+  assert(stream_c_locale<CharT>(std::chrono::file_time<std::chrono::microseconds>{-946'688'523'123'456us}) ==
+         SV("1940-01-01 22:57:56.876544"));
+
+  assert(stream_c_locale<CharT>(std::chrono::file_time<std::chrono::milliseconds>{-946'688'523'123ms}) ==
+         SV("1940-01-01 22:57:56.877"));
+
+  assert(stream_c_locale<CharT>(std::chrono::file_time<std::chrono::nanoseconds>{-1ns}) ==
+         SV("1969-12-31 23:59:59.999999999"));
+
+  assert(stream_c_locale<CharT>(std::chrono::file_time<std::chrono::nanoseconds>{0ns}) ==
+         SV("1970-01-01 00:00:00.000000000"));
+
+  assert(stream_c_locale<CharT>(std::chrono::file_time<std::chrono::nanoseconds>{1ns}) ==
+         SV("1970-01-01 00:00:00.000000001"));
+
   assert(stream_c_locale<CharT>(file_time<std::chrono::nanoseconds>{946'688'523'123'456'789ns}) ==
          SV("2000-01-01 01:02:03.123456789"));
   assert(stream_c_locale<CharT>(file_time<std::chrono::microseconds>{946'688'523'123'456us}) ==
@@ -107,6 +125,24 @@ template <class CharT>
 static void test_fr_FR() {
   using namespace std::literals::chrono_literals;
 
+  assert(stream_fr_FR_locale<CharT>(std::chrono::file_time<std::chrono::nanoseconds>{-946'688'523'123'456'789ns}) ==
+         SV("1940-01-01 22:57:56,876543211"));
+
+  assert(stream_fr_FR_locale<CharT>(std::chrono::file_time<std::chrono::microseconds>{-946'688'523'123'456us}) ==
+         SV("1940-01-01 22:57:56,876544"));
+
+  assert(stream_fr_FR_locale<CharT>(std::chrono::file_time<std::chrono::milliseconds>{-946'688'523'123ms}) ==
+         SV("1940-01-01 22:57:56,877"));
+
+  assert(stream_fr_FR_locale<CharT>(std::chrono::file_time<std::chrono::nanoseconds>{-1ns}) ==
+         SV("1969-12-31 23:59:59,999999999"));
+
+  assert(stream_fr_FR_locale<CharT>(std::chrono::file_time<std::chrono::nanoseconds>{0ns}) ==
+         SV("1970-01-01 00:00:00,000000000"));
+
+  assert(stream_fr_FR_locale<CharT>(std::chrono::file_time<std::chrono::nanoseconds>{1ns}) ==
+         SV("1970-01-01 00:00:00,000000001"));
+
   assert(stream_fr_FR_locale<CharT>(file_time<std::chrono::nanoseconds>{946'688'523'123'456'789ns}) ==
          SV("2000-01-01 01:02:03,123456789"));
   assert(stream_fr_FR_locale<CharT>(file_time<std::chrono::microseconds>{946'688'523'123'456us}) ==
@@ -144,6 +180,24 @@ template <class CharT>
 static void test_ja_JP() {
   using namespace std::literals::chrono_literals;
 
+  assert(stream_ja_JP_locale<CharT>(std::chrono::file_time<std::chrono::nanoseconds>{-946'688'523'123'456'789ns}) ==
+         SV("1940-01-01 22:57:56.876543211"));
+
+  assert(stream_ja_JP_locale<CharT>(std::chrono::file_time<std::chrono::microseconds>{-946'688'523'123'456us}) ==
+         SV("1940-01-01 22:57:56.876544"));
+
+  assert(stream_ja_JP_locale<CharT>(std::chrono::file_time<std::chrono::milliseconds>{-946'688'523'123ms}) ==
+         SV("1940-01-01 22:57:56.877"));
+
+  assert(stream_ja_JP_locale<CharT>(std::chrono::file_time<std::chrono::nanoseconds>{-1ns}) ==
+         SV("1969-12-31 23:59:59.999999999"));
+
+  assert(stream_ja_JP_locale<CharT>(std::chrono::file_time<std::chrono::nanoseconds>{0ns}) ==
+         SV("1970-01-01 00:00:00.000000000"));
+
+  assert(stream_ja_JP_locale<CharT>(std::chrono::file_time<std::chrono::nanoseconds>{1ns}) ==
+         SV("1970-01-01 00:00:00.000000001"));
+
   assert(stream_ja_JP_locale<CharT>(file_time<std::chrono::nanoseconds>{946'688'523'123'456'789ns}) ==
          SV("2000-01-01 01:02:03.123456789"));
   assert(stream_ja_JP_locale<CharT>(file_time<std::chrono::microseconds>{946'688'523'123'456us}) ==
diff --git a/libcxx/test/std/time/time.clock/time.clock.local/ostream.pass.cpp b/libcxx/test/std/time/time.clock/time.clock.local/ostream.pass.cpp
index 9fdef8d5adc782..6ec63a14fbbd33 100644
--- a/libcxx/test/std/time/time.clock/time.clock.local/ostream.pass.cpp
+++ b/libcxx/test/std/time/time.clock/time.clock.local/ostream.pass.cpp
@@ -64,6 +64,24 @@ template <class CharT>
 static void test_c() {
   using namespace std::literals::chrono_literals;
 
+  assert(stream_c_locale<CharT>(std::chrono::local_time<std::chrono::nanoseconds>{-946'688'523'123'456'789ns}) ==
+         SV("1940-01-01 22:57:56.876543211"));
+
+  assert(stream_c_locale<CharT>(std::chrono::local_time<std::chrono::microseconds>{-946'688'523'123'456us}) ==
+         SV("1940-01-01 22:57:56.876544"));
+
+  assert(stream_c_locale<CharT>(std::chrono::local_time<std::chrono::milliseconds>{-946'688'523'123ms}) ==
+         SV("1940-01-01 22:57:56.877"));
+
+  assert(stream_c_locale<CharT>(std::chrono::local_time<std::chrono::nanoseconds>{-1ns}) ==
+         SV("1969-12-31 23:59:59.999999999"));
+
+  assert(stream_c_locale<CharT>(std::chrono::local_time<std::chrono::nanoseconds>{0ns}) ==
+         SV("1970-01-01 00:00:00.000000000"));
+
+  assert(stream_c_locale<CharT>(std::chrono::local_time<std::chrono::nanoseconds>{1ns}) ==
+         SV("1970-01-01 00:00:00.000000001"));
+
   assert(stream_c_locale<CharT>(std::chrono::local_time<std::chrono::nanoseconds>{946'688'523'123'456'789ns}) ==
          SV("2000-01-01 01:02:03.123456789"));
   assert(stream_c_locale<CharT>(std::chrono::local_time<std::chrono::microseconds>{946'688'523'123'456us}) ==
@@ -97,6 +115,24 @@ template <class CharT>
 static void test_fr_FR() {
   using namespace std::literals::chrono_literals;
 
+  assert(stream_fr_FR_locale<CharT>(std::chrono::local_time<std::chrono::nanoseconds>{-946'688'523'123'456'789ns}) ==
+         SV("1940-01-01 22:57:56,876543211"));
+
+  assert(stream_fr_FR_locale<CharT>(std::chrono::local_time<std::chrono::microseconds>{-946'688'523'123'456us}) ==
+         SV("1940-01-01 22:57:56,876544"));
+
+  assert(stream_fr_FR_locale<CharT>(std::chrono::local_time<std::chrono::milliseconds>{-946'688'523'123ms}) ==
+         SV("1940-01-01 22:57:56,877"));
+
+  assert(stream_fr_FR_locale<CharT>(std::chrono::local_time<std::chrono::nanoseconds>{-1ns}) ==
+         SV("1969-12-31 23:59:59,999999999"));
+
+  assert(stream_fr_FR_locale<CharT>(std::chrono::local_time<std::chrono::nanoseconds>{0ns}) ==
+         SV("1970-01-01 00:00:00,000000000"));
+
+  assert(stream_fr_FR_locale<CharT>(std::chrono::local_time<std::chrono::nanoseconds>{1ns}) ==
+         SV("1970-01-01 00:00:00,000000001"));
+
   assert(stream_fr_FR_locale<CharT>(std::chrono::local_time<std::chrono::nanoseconds>{946'688'523'123'456'789ns}) ==
          SV("2000-01-01 01:02:03,123456789"));
   assert(stream_fr_FR_locale<CharT>(std::chrono::local_time<std::chrono::microseconds>{946'688'523'123'456us}) ==
@@ -131,6 +167,24 @@ template <class CharT>
 static void test_ja_JP() {
   using namespace std::literals::chrono_literals;
 
+  assert(stream_ja_JP_locale<CharT>(std::chrono::local_time<std::chrono::nanoseconds>{-946'688'523'123'456'789ns}) ==
+         SV("1940-01-01 22:57:56.876543211"));
+
+  assert(stream_ja_JP_locale<CharT>(std::chrono::local_time<std::chrono::microseconds>{-946'688'523'123'456us}) ==
+         SV("1940-01-01 22:57:56.876544"));
+
+  assert(stream_ja_JP_locale<CharT>(std::chrono::local_time<std::chrono::milliseconds>{-946'688'523'123ms}) ==
+         SV("1940-01-01 22:57:56.877"));
+
+  assert(stream_ja_JP_locale<CharT>(std::chrono::local_time<std::chrono::nanoseconds>{-1ns}) ==
+         SV("1969-12-31 23:59:59.999999999"));
+
+  assert(stream_ja_JP_locale<CharT>(std::chrono::local_time<std::chrono::nanoseconds>{0ns}) ==
+         SV("1970-01-01 00:00:00.000000000"));
+
+  assert(stream_ja_JP_locale<CharT>(std::chrono::local_time<std::chrono::nanoseconds>{1ns}) ==
+         SV("1970-01-01 00:00:00.000000001"));
+
   assert(stream_ja_JP_locale<CharT>(std::chrono::local_time<std::chrono::nanoseconds>{946'688'523'123'456'789ns}) ==
          SV("2000-01-01 01:02:03.123456789"));
   assert(stream_ja_JP_locale<CharT>(std::chrono::local_time<std::chrono::microseconds>{946'688'523'123'456us}) ==
diff --git a/libcxx/test/std/time/time.clock/time.clock.system/sys_time.ostream.pass.cpp b/libcxx/test/std/time/time.clock/time.clock.system/sys_time.ostream.pass.cpp
index 78d8da57c150a6..e596ddefde51d9 100644
--- a/libcxx/test/std/time/time.clock/time.clock.system/sys_time.ostream.pass.cpp
+++ b/libcxx/test/std/time/time.clock/time.clock.system/sys_time.ostream.pass.cpp
@@ -64,6 +64,24 @@ template <class CharT>
 static void test_c() {
   using namespace std::literals::chrono_literals;
 
+  assert(stream_c_locale<CharT>(std::chrono::sys_time<std::chrono::nanoseconds>{-946'688'523'123'456'789ns}) ==
+         SV("1940-01-01 22:57:56.876543211"));
+
+  assert(stream_c_locale<CharT>(std::chrono::sys_time<std::chrono::microseconds>{-946'688'523'123'456us}) ==
+         SV("1940-01-01 22:57:56.876544"));
+
+  assert(stream_c_locale<CharT>(std::chrono::sys_time<std::chrono::milliseconds>{-946'688'523'123ms}) ==
+         SV("1940-01-01 22:57:56.877"));
+
+  assert(stream_c_locale<CharT>(std::chrono::sys_time<std::chrono::nanoseconds>{-1ns}) ==
+         SV("1969-12-31 23:59:59.999999999"));
+
+  assert(stream_c_locale<CharT>(std::chrono::sys_time<std::chrono::nanoseconds>{0ns}) ==
+         SV("1970-01-01 00:00:00.000000000"));
+
+  assert(stream_c_locale<CharT>(std::chrono::sys_time<std::chrono::nanoseconds>{1ns}) ==
+         SV("1970-01-01 00:00:00.000000001"));
+
   assert(stream_c_locale<CharT>(std::chrono::sys_time<std::chrono::nanoseconds>{946'688'523'123'456'789ns}) ==
          SV("2000-01-01 01:02:03.123456789"));
   assert(stream_c_locale<CharT>(std::chrono::sys_time<std::chrono::microseconds>{946'688'523'123'456us}) ==
@@ -92,6 +110,24 @@ template <class CharT>
 static void test_fr_FR() {
   using namespace std::literals::chrono_literals;
 
+  assert(stream_fr_FR_locale<CharT>(std::chrono::sys_time<std::chrono::nanoseconds>{-946'688'523'123'456'789ns}) ==
+         SV("1940-01-01 22:57:56,876543211"));
+
+  assert(stream_fr_FR_locale<CharT>(std::chrono::sys_time<std::chrono::microseconds>{-946'688'523'123'456us}) ==
+         SV("1940-01-01 22:57:56,876544"));
+
+  assert(stream_fr_FR_locale<CharT>(std::chrono::sys_time<std::chrono::milliseconds>{-946'688'523'123ms}) ==
+         SV("1940-01-01 22:57:56,877"));
+
+  assert(stream_fr_FR_locale<CharT>(std::chrono::sys_time<std::chrono::nanoseconds>{-1ns}) ==
+         SV("1969-12-31 23:59:59,999999999"));
+
+  assert(stream_fr_FR_locale<CharT>(std::chrono::sys_time<std::chrono::nanoseconds>{0ns}) ==
+         SV("1970-01-01 00:00:00,000000000"));
+
+  assert(stream_fr_FR_locale<CharT>(std::chrono::sys_time<std::chrono::nanoseconds>{1ns}) ==
+         SV("1970-01-01 00:00:00,000000001"));
+
   assert(stream_fr_FR_locale<CharT>(std::chrono::sys_time<std::chrono::nanoseconds>{946'688'523'123'456'789ns}) ==
          SV("2000-01-01 01:02:03,123456789"));
   assert(stream_fr_FR_locale<CharT>(std::chrono::sys_time<std::chrono::microseconds>{946'688'523'123'456us}) ==
@@ -120,6 +156,24 @@ template <class CharT>
 static void test_ja_JP() {
   using namespace std::literals::chrono_literals;
 
+  assert(stream_ja_JP_locale<CharT>(std::chrono::sys_time<std::chrono::nanoseconds>{-946'688'523'123'456'789ns}) ==
+         SV("1940-01-01 22:57:56.876543211"));
+
+  assert(stream_ja_JP_locale<CharT>(std::chrono::sys_time<std::chrono::microseconds>{-946'688'523'123'456us}) ==
+         SV("1940-01-01 22:57:56.876544"));
+
+  assert(stream_ja_JP_locale<CharT>(std::chrono::sys_time<std::chrono::milliseconds>{-946'688'523'123ms}) ==
+         SV("1940-01-01 22:57:56.877"));
+
+  assert(stream_ja_JP_locale<CharT>(std::chrono::sys_time<std::chrono::nanoseconds>{-1ns}) ==
+         SV("1969-12-31 23:59:59.999999999"));
+
+  assert(stream_ja_JP_locale<CharT>(std::chrono::sys_time<std::chrono::nanoseconds>{0ns}) ==
+         SV("1970-01-01 00:00:00.000000000"));
+
+  assert(stream_ja_JP_locale<CharT>(std::chrono::sys_time<std::chrono::nanoseconds>{1ns}) ==
+         SV("1970-01-01 00:00:00.000000001"));
+
   assert(stream_ja_JP_locale<CharT>(std::chrono::sys_time<std::chrono::nanoseconds>{946'688'523'123'456'789ns}) ==
          SV("2000-01-01 01:02:03.123456789"));
   assert(stream_ja_JP_locale<CharT>(std::chrono::sys_time<std::chrono::microseconds>{946'688'523'123'456us}) ==

Base automatically changed from users/mordante/tzdb_renames_incomplete to main April 20, 2024 10:09
@mordante
[libc++][chrono] Fixes format output of negative values.
d37de3b 
The negative values were shown as

  1900-01-01 00:01:39.-00000001

after the changes they are shown as

  1900-01-01 00:01:39.999999999
@mordante mordante force-pushed the users/mordante/fixes_formatting_timepoints_before_epoch branch from 11fa6e8 to d37de3b Compare April 20, 2024 10:10
@ldionne ldionne self-assigned this Apr 23, 2024
@mordante mordante merged commit 579d301 into main Apr 23, 2024
@mordante mordante deleted the users/mordante/fixes_formatting_timepoints_before_epoch branch April 23, 2024 17:42
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@ldionne ldionne ldionne approved these changes

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