Export of internal Abseil changes.

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86b1c997fac1f77b0eacfab788659b5a89a6096e by Abseil Team <absl-team@google.com>:

Import of CCTZ from GitHub.

PiperOrigin-RevId: 211654320

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299b70e1247df768454a76eb957a184de9706f61 by Chris Kennelly <ckennelly@google.com>:

Avoid creating a misaligned reference to int.

PiperOrigin-RevId: 211505883

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c8fad4357ad0bfb3c5ad197c505509bc087072c9 by Abseil Team <absl-team@google.com>:

Import of CCTZ from GitHub.

PiperOrigin-RevId: 211458539

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0613feffcd36466c3e53a50758d7e8f17c001dce by Greg Falcon <gfalcon@google.com>:

Refactor a string unit test into a template function for internal purposes.

PiperOrigin-RevId: 211100748
GitOrigin-RevId: 86b1c997fac1f77b0eacfab788659b5a89a6096e
Change-Id: Ic6a932b6c27c6762dcdb3b0127f1e2be782418c1

4 files changed, 32 insertions, 36 deletions

diff --git a/absl/time/internal/cctz/include/cctz/civil_time_detail.h b/absl/time/internal/cctz/include/cctz/civil_time_detail.h
index f831258..5fe0967 100644
--- a/absl/time/internal/cctz/include/cctz/civil_time_detail.h
+++ b/absl/time/internal/cctz/include/cctz/civil_time_detail.h
@@ -508,12 +508,8 @@ CONSTEXPR_F weekday get_weekday(const civil_day& cd) noexcept {
   CONSTEXPR_D int k_weekday_offsets[1 + 12] = {
       -1, 0, 3, 2, 5, 0, 3, 5, 1, 4, 6, 2, 4,
   };
-  year_t wd = cd.year() - (cd.month() < 3);
-  if (wd >= 0) {
-    wd += wd / 4 - wd / 100 + wd / 400;
-  } else {
-    wd += (wd - 3) / 4 - (wd - 99) / 100 + (wd - 399) / 400;
-  }
+  year_t wd = 2400 + (cd.year() % 400) - (cd.month() < 3);
+  wd += wd / 4 - wd / 100 + wd / 400;
   wd += k_weekday_offsets[cd.month()] + cd.day();
   return k_weekday_by_sun_off[(wd % 7 + 7) % 7];
 }
diff --git a/absl/time/internal/cctz/src/cctz_benchmark.cc b/absl/time/internal/cctz/src/cctz_benchmark.cc
index c97df78..4498d7d 100644
--- a/absl/time/internal/cctz/src/cctz_benchmark.cc
+++ b/absl/time/internal/cctz/src/cctz_benchmark.cc
@@ -778,13 +778,13 @@ void BM_Zone_UTCTimeZone(benchmark::State& state) {
 }
 BENCHMARK(BM_Zone_UTCTimeZone);
 
-// In each "ToDateTime" benchmark we switch between two instants
-// separated by at least one transition in order to defeat any
-// internal caching of previous results (e.g., see local_time_hint_).
+// In each "ToCivil" benchmark we switch between two instants separated
+// by at least one transition in order to defeat any internal caching of
+// previous results (e.g., see local_time_hint_).
 //
 // The "UTC" variants use UTC instead of the Google/local time zone.
 
-void BM_Time_ToDateTime_CCTZ(benchmark::State& state) {
+void BM_Time_ToCivil_CCTZ(benchmark::State& state) {
   const cctz::time_zone tz = TestTimeZone();
   std::chrono::system_clock::time_point tp =
       std::chrono::system_clock::from_time_t(1384569027);
@@ -796,9 +796,9 @@ void BM_Time_ToDateTime_CCTZ(benchmark::State& state) {
     benchmark::DoNotOptimize(cctz::convert(tp, tz));
   }
 }
-BENCHMARK(BM_Time_ToDateTime_CCTZ);
+BENCHMARK(BM_Time_ToCivil_CCTZ);
 
-void BM_Time_ToDateTime_Libc(benchmark::State& state) {
+void BM_Time_ToCivil_Libc(benchmark::State& state) {
   // No timezone support, so just use localtime.
   time_t t = 1384569027;
   time_t t2 = 1418962578;
@@ -813,9 +813,9 @@ void BM_Time_ToDateTime_Libc(benchmark::State& state) {
 #endif
   }
 }
-BENCHMARK(BM_Time_ToDateTime_Libc);
+BENCHMARK(BM_Time_ToCivil_Libc);
 
-void BM_Time_ToDateTimeUTC_CCTZ(benchmark::State& state) {
+void BM_Time_ToCivilUTC_CCTZ(benchmark::State& state) {
   const cctz::time_zone tz = cctz::utc_time_zone();
   std::chrono::system_clock::time_point tp =
       std::chrono::system_clock::from_time_t(1384569027);
@@ -824,9 +824,9 @@ void BM_Time_ToDateTimeUTC_CCTZ(benchmark::State& state) {
     benchmark::DoNotOptimize(cctz::convert(tp, tz));
   }
 }
-BENCHMARK(BM_Time_ToDateTimeUTC_CCTZ);
+BENCHMARK(BM_Time_ToCivilUTC_CCTZ);
 
-void BM_Time_ToDateTimeUTC_Libc(benchmark::State& state) {
+void BM_Time_ToCivilUTC_Libc(benchmark::State& state) {
   time_t t = 1384569027;
   struct tm tm;
   while (state.KeepRunning()) {
@@ -838,16 +838,16 @@ void BM_Time_ToDateTimeUTC_Libc(benchmark::State& state) {
 #endif
   }
 }
-BENCHMARK(BM_Time_ToDateTimeUTC_Libc);
+BENCHMARK(BM_Time_ToCivilUTC_Libc);
 
-// In each "FromDateTime" benchmark we switch between two YMDhms
-// values separated by at least one transition in order to defeat any
-// internal caching of previous results (e.g., see time_local_hint_).
+// In each "FromCivil" benchmark we switch between two YMDhms values
+// separated by at least one transition in order to defeat any internal
+// caching of previous results (e.g., see time_local_hint_).
 //
 // The "UTC" variants use UTC instead of the Google/local time zone.
 // The "Day0" variants require normalization of the day of month.
 
-void BM_Time_FromDateTime_CCTZ(benchmark::State& state) {
+void BM_Time_FromCivil_CCTZ(benchmark::State& state) {
   const cctz::time_zone tz = TestTimeZone();
   int i = 0;
   while (state.KeepRunning()) {
@@ -860,9 +860,9 @@ void BM_Time_FromDateTime_CCTZ(benchmark::State& state) {
     }
   }
 }
-BENCHMARK(BM_Time_FromDateTime_CCTZ);
+BENCHMARK(BM_Time_FromCivil_CCTZ);
 
-void BM_Time_FromDateTime_Libc(benchmark::State& state) {
+void BM_Time_FromCivil_Libc(benchmark::State& state) {
   // No timezone support, so just use localtime.
   int i = 0;
   while (state.KeepRunning()) {
@@ -886,20 +886,20 @@ void BM_Time_FromDateTime_Libc(benchmark::State& state) {
     benchmark::DoNotOptimize(mktime(&tm));
   }
 }
-BENCHMARK(BM_Time_FromDateTime_Libc);
+BENCHMARK(BM_Time_FromCivil_Libc);
 
-void BM_Time_FromDateTimeUTC_CCTZ(benchmark::State& state) {
+void BM_Time_FromCivilUTC_CCTZ(benchmark::State& state) {
   const cctz::time_zone tz = cctz::utc_time_zone();
   while (state.KeepRunning()) {
     benchmark::DoNotOptimize(
         cctz::convert(cctz::civil_second(2014, 12, 18, 20, 16, 18), tz));
   }
 }
-BENCHMARK(BM_Time_FromDateTimeUTC_CCTZ);
+BENCHMARK(BM_Time_FromCivilUTC_CCTZ);
 
-// There is no BM_Time_FromDateTimeUTC_Libc.
+// There is no BM_Time_FromCivilUTC_Libc.
 
-void BM_Time_FromDateTimeDay0_CCTZ(benchmark::State& state) {
+void BM_Time_FromCivilDay0_CCTZ(benchmark::State& state) {
   const cctz::time_zone tz = TestTimeZone();
   int i = 0;
   while (state.KeepRunning()) {
@@ -912,9 +912,9 @@ void BM_Time_FromDateTimeDay0_CCTZ(benchmark::State& state) {
     }
   }
 }
-BENCHMARK(BM_Time_FromDateTimeDay0_CCTZ);
+BENCHMARK(BM_Time_FromCivilDay0_CCTZ);
 
-void BM_Time_FromDateTimeDay0_Libc(benchmark::State& state) {
+void BM_Time_FromCivilDay0_Libc(benchmark::State& state) {
   // No timezone support, so just use localtime.
   int i = 0;
   while (state.KeepRunning()) {
@@ -938,7 +938,7 @@ void BM_Time_FromDateTimeDay0_Libc(benchmark::State& state) {
     benchmark::DoNotOptimize(mktime(&tm));
   }
 }
-BENCHMARK(BM_Time_FromDateTimeDay0_Libc);
+BENCHMARK(BM_Time_FromCivilDay0_Libc);
 
 const char* const kFormats[] = {
     RFC1123_full,         // 0
diff --git a/absl/time/internal/cctz/src/time_zone_format.cc b/absl/time/internal/cctz/src/time_zone_format.cc
index d971409..a02b1e3 100644
--- a/absl/time/internal/cctz/src/time_zone_format.cc
+++ b/absl/time/internal/cctz/src/time_zone_format.cc
@@ -743,7 +743,7 @@ bool parse(const std::string& format, const std::string& input,
     data = ParseTM(data, spec.c_str(), &tm);
 
     // If we successfully parsed %p we need to remember whether the result
-    // was AM or PM so that we can adjust tm_hour before ConvertDateTime().
+    // was AM or PM so that we can adjust tm_hour before time_zone::lookup().
     // So reparse the input with a known AM hour, and check if it is shifted
     // to a PM hour.
     if (spec == "%p" && data != nullptr) {
diff --git a/absl/time/internal/cctz/src/time_zone_format_test.cc b/absl/time/internal/cctz/src/time_zone_format_test.cc
index a90dda7..6b9928e 100644
--- a/absl/time/internal/cctz/src/time_zone_format_test.cc
+++ b/absl/time/internal/cctz/src/time_zone_format_test.cc
@@ -669,13 +669,13 @@ TEST(Parse, WithTimeZone) {
                     utc_time_zone(), &tp));
   ExpectTime(tp, tz, 2013, 6, 28, 19 - 8 - 7, 8, 9, -7 * 60 * 60, true, "PDT");
 
-  // Check a skipped time (a Spring DST transition).  parse() returns
-  // the preferred-offset result, as defined for ConvertDateTime().
+  // Check a skipped time (a Spring DST transition). parse() uses the
+  // pre-transition offset.
   EXPECT_TRUE(parse("%Y-%m-%d %H:%M:%S", "2011-03-13 02:15:00", tz, &tp));
   ExpectTime(tp, tz, 2011, 3, 13, 3, 15, 0, -7 * 60 * 60, true, "PDT");
 
-  // Check a repeated time (a Fall DST transition).  parse() returns
-  // the preferred-offset result, as defined for ConvertDateTime().
+  // Check a repeated time (a Fall DST transition).  parse() uses the
+  // pre-transition offset.
   EXPECT_TRUE(parse("%Y-%m-%d %H:%M:%S", "2011-11-06 01:15:00", tz, &tp));
   ExpectTime(tp, tz, 2011, 11, 6, 1, 15, 0, -7 * 60 * 60, true, "PDT");
 }