Creation of LTS branch "lts_2018_12_18"20181200

  - 44b0fafc62d9b8f192e8180cbe9c4b806b339d57 Export of internal Abseil changes. by Abseil Team <absl-team@google.com>
  - 926bfeb9fff223429c12224b7514243886323e8d Export of internal Abseil changes. by Abseil Team <absl-team@google.com>
  - 13327debebc5c2d1d4991b69fe50450e340e50e4 Export of internal Abseil changes. by Abseil Team <absl-team@google.com>
  - 3088e76c597e068479e82508b1770a7ad0c806b6 Export of internal Abseil changes. by Abseil Team <absl-team@google.com>
  - f6ae816808cd913e0e2b3e2af14f328fa1071af0 Export of internal Abseil changes. by Abseil Team <absl-team@google.com>
  - a06c4a1d9093137b7217a5aaba8920d62e835dc0 Export of internal Abseil changes. by Abseil Team <absl-team@google.com>
  - 7b46e1d31a6b08b1c6da2a13e7b151a20446fa07 Export of internal Abseil changes. by Abseil Team <absl-team@google.com>
  - 070f6e47b33a2909d039e620c873204f78809492 Export of internal Abseil changes. by Abseil Team <absl-team@google.com>
  - 7990fd459e9339467814ddb95000c87cb1e4d945 Export of internal Abseil changes. by Abseil Team <absl-team@google.com>
  - f95179062eb65ce40895cc76f1398cce25394369 Export of internal Abseil changes. by Abseil Team <absl-team@google.com>
  - cc8dcd307b76a575d2e3e0958a4fe4c7193c2f68 Export of internal Abseil changes. by Abseil Team <absl-team@google.com>
  - a705aa78dc76fc5c79d501e61dcc077eca68a8a4 Merge pull request #194 from Mizux/windows by Xiaoyi Zhang <zhangxy988@gmail.com>
  - a4c3ffff11eec0ee45742f915c255e9f870b7e0f Export of internal Abseil changes. by Abseil Team <absl-team@google.com>
  - 01174578651b73021d9b8c3820f6fea707dacdf0 Merge pull request #201 from ccawley2011/fix-byteswap by Matt Calabrese <38107210+mattcalabrese-google@users.noreply.github.com>
  - f86f9413856b65afdd61fea938d684b8ab73115a Export of internal Abseil changes. by Abseil Team <absl-team@google.com>
  - 94c298e2a0ae409e283cab96c954a685bd865a70 Export of internal Abseil changes. by Abseil Team <absl-team@google.com>
  - 0884a6a04e4497d11b1b398cc0e422b118bf977a Export of internal Abseil changes. by Abseil Team <absl-team@google.com>
  - c16d5557cd05119b5b7b1318ef778ebe3195b4a1 Export of internal Abseil changes. by Abseil Team <absl-team@google.com>
  - 45221ccc4ed643e4209b0cc5798e97203f108fa8 Export of internal Abseil changes. by Abseil Team <absl-team@google.com>
  - 2019e17a520575ab365b2b5134d71068182c70b8 Export of internal Abseil changes. by Abseil Team <absl-team@google.com>
  - 5b70a8910b2e6fb0ce5193a41873139a126d2f7f Export of internal Abseil changes. by Abseil Team <absl-team@google.com>
  - a00bdd176d66ef0b417d9576052a19091fbdf891 Export of internal Abseil changes. by Abseil Team <absl-team@google.com>
  - f340f773edab951656b19b6f1a77c964a78ec4c2 Export of internal Abseil changes. by Abseil Team <absl-team@google.com>
  - 445998d7ac4e5d3c50411d377e3b50e960d2d6c2 Export of internal Abseil changes. by Abseil Team <absl-team@google.com>
  - e821380d69a549dc64900693942789d21aa4df5e Export of internal Abseil changes. by Abseil Team <absl-team@google.com>
  - f21d187b80e3b7f08fb279775ea9c8b48c636030 Export of internal Abseil changes. by Abseil Team <absl-team@google.com>
  - 5441bbe1db5d0f2ca24b5b60166367b0966790af Fix code snippet in comment (#174) by Loo Rong Jie <loorongjie@gmail.com>
  - 5aae0cffae8ffaacab965756169b34e511b353df Fix CMake build (#173) by Stephan Dollberg <stephan.dollberg@gmail.com>
  - 48cd2c3f351ff188bc85684b84a91b6e6d17d896 Export of internal Abseil changes. by Abseil Team <absl-team@google.com>
  - e291c279e458761e77a69b09b129d3d1e81f1e80 Export of internal Abseil changes. by Abseil Team <absl-team@google.com>
  - e01d95528ea2137a4a27a88d1f57c6cb260aafed Export of internal Abseil changes. by Abseil Team <absl-team@google.com>
  - 8ff1374008259719b54a8cb128ef951c02da164c Export of internal Abseil changes. by Abseil Team <absl-team@google.com>
  - 02451914b9ad5320f81f56a89f3eef1f8683227c Export of internal Abseil changes. by Abseil Team <absl-team@google.com>
  - 921fd5cf02ec0d665439a790148d59faa7d4a72c Merge pull request #166 from rongjiecomputer/cmake-test by Gennadiy Civil <gennadiycivil@users.noreply.github.com>
  - fb462224c058487763f263b7995d70efd0242c17 Export of internal Abseil changes. by Abseil Team <absl-team@google.com>
  - c075ad321696fa5072e097f0a51e4fe76a6fe13e Export of internal Abseil changes. by Abseil Team <absl-team@google.com>
  - 0f4bc966754ec6cd28d5f03467d56f1efdc598e3 Export of internal Abseil changes. by Abseil Team <absl-team@google.com>
  - 6c7e5ffc43decd92f7bdfc510ad8a245a20b6dea Export of internal Abseil changes. by Abseil Team <absl-team@google.com>
  - d6df769173bf0263489f98874b93034db0e479a2 Export of internal Abseil changes. by Abseil Team <absl-team@google.com>
  - 28080f5f050c9530aa9f2b39c60d8217038d64ff Export of internal Abseil changes. by Abseil Team <absl-team@google.com>
  - 9c987f429bba32fb4446280fd3b91e2472d71d4d Export of internal Abseil changes. by Abseil Team <absl-team@google.com>
  - 5e7d459eeca7bc53deab0ee9634601386b53d7c0 Export of internal Abseil changes. by Abseil Team <absl-team@google.com>
  - bed5bd6e185c7e0311f3a1f2dab4c96083dac636 Export of internal Abseil changes. by Abseil Team <absl-team@google.com>
  - fefc83638fb69395d259ed245699310610429064 Export of internal Abseil changes. by Abseil Team <absl-team@google.com>
  - d8cfe9f2a77fbee02c09642491e62a3f3677e0f6 Export of internal Abseil changes. by Abseil Team <absl-team@google.com>
  - ad5c960b2eb914881d1ceba0e996a0a8f3f6ca59 Export of internal Abseil changes. by Abseil Team <absl-team@google.com>
  - 86f0fe93ad9d6d033a319476736a3256369c1f75 Export of internal Abseil changes. by Abseil Team <absl-team@google.com>
  - f0f15c2778b0e4959244dd25e63f445a455870f5 Export of internal Abseil changes. by Abseil Team <absl-team@google.com>
  - 29ff6d4860070bf8fcbd39c8805d0c32d56628a3 Removed "warning treated as error" flag from MSVC (#153) by vocaviking <vocaviking@users.noreply.github.com>
  - 083d04dd4a62ebbf037079b06e49b323c5e1192a Export of internal Abseil changes. by Abseil Team <absl-team@google.com>
  - bea85b52733022294eef108a2e42d77b616ddca2 Export of internal Abseil changes. by Abseil Team <absl-team@google.com>
  - 8f96be6ca60d967bd4b37f93d0a03bcff4145200 Export of internal Abseil changes. by Abseil Team <absl-team@google.com>
  - 92e07e5590752d6b8e67f7f2f86c6286561e8cea Merge pull request #152 from clnperez/fix-multi-defines-p... by Derek Mauro <761129+derekmauro@users.noreply.github.com>
  - 2125e6444a9de9e41f21ecdc674dd7d8759c149d Export of internal Abseil changes. by Abseil Team <absl-team@google.com>
  - 9acad869d21731f5bc50430a33fe61cc0ffcbb0b Merge pull request #150 from OlafvdSpek/patch-2 by Jonathan Cohen <cohenjon@google.com>
  - c2e00d341913bf03b4597ade5b056042e23e8c58 Export of internal Abseil changes. by Abseil Team <absl-team@google.com>
  - 9e060686d1c325f34f9806b45fe77bafeed00aee Export of internal Abseil changes. by Abseil Team <absl-team@google.com>
  - 7aa411ceafc1272a28579cca739a97a2fb79055a Export of internal Abseil changes. by Abseil Team <absl-team@google.com>
  - 2c5af55ed34850d8b7dd46177c8ca53fdfda920e Export of internal Abseil changes. by Abseil Team <absl-team@google.com>
  - 44aa275286baf97fc13529aca547a88b180beb08 Merge pull request #143 from rongjiecomputer/kernel by Xiaoyi Zhang <zhangxy988@gmail.com>
  - 42f22a28401c952f1fc5942231c7fdac80811bf5 Export of internal Abseil changes. by Abseil Team <absl-team@google.com>
  - b973bc53ef366f0253b85eeed9a79b241884a843 Merge pull request #139 from siepkes/smartos-support by ahedberg <ahedberg@google.com>
  - e0def7473e52336f58759e11db4cd9467e5e0356 Export of internal Abseil changes. by Abseil Team <absl-team@google.com>
  - f826f1d489b61b64df1d94afbe5981841a82e5fa Merge pull request #138 from edbaunton/remove-deprecated-... by ahedberg <ahedberg@google.com>
  - 7b50a4a94b0c7df68b3a854c850b551aaef0a8b4 Export of internal Abseil changes. by Abseil Team <absl-team@google.com>
  - a5030ca5125b9d557ecfeea8acc8b1a8e49f6d27 Merge pull request #144 from rongjiecomputer/winsock2 by Xiaoyi Zhang <zhangxy988@gmail.com>
  - 02687955b7ca8fc02ada9b14bc247deeb108d341 Export of internal Abseil changes. by Abseil Team <absl-team@google.com>
  - 8f612ebb152fb7e05643a2bcf78cb89a8c0641ad Export of internal Abseil changes. by Abseil Team <absl-team@google.com>
  - 134496a31d8b324f762de3bee9a002658c984456 Export of internal Abseil changes. by Abseil Team <absl-team@google.com>
  - ba8d6cf07766263723e86736f20a51c1c9c67b19 Export of internal Abseil changes. by Abseil Team <absl-team@google.com>
  - be1e84b988fceabcea4fc9e93f899539f0c81901 Export of internal Abseil changes. by Abseil Team <absl-team@google.com>
  - 16ac2ec2e38cdf47f9330a312e319d57da659c10 Merge pull request #134 from rongjiecomputer/cmake by Alex Strelnikov <strel@google.com>
  - 7efd8dc0f1075356e9c7caa950afd1ecf854e8b9 Export of internal Abseil changes. by Abseil Team <absl-team@google.com>
  - 87a4c07856e7dc69958019d47b2f02ae47746ec0 Export of internal Abseil changes. by Abseil Team <absl-team@google.com>
  - 4491d606df34c44efda47b6d17b605262f17e182 Export of internal Abseil changes. by Abseil Team <absl-team@google.com>

GitOrigin-RevId: 44b0fafc62d9b8f192e8180cbe9c4b806b339d57
Change-Id: I2c427b5b41b2d34101922048b00f3d9dafcb498d

1 files changed, 219 insertions, 119 deletions

diff --git a/absl/time/time.cc b/absl/time/time.cc
index 76ce12c9..e60857e2 100644
--- a/absl/time/time.cc
+++ b/absl/time/time.cc
@@ -22,13 +22,14 @@
 // NOTE: To keep type verbosity to a minimum, the following variable naming
 // conventions are used throughout this file.
 //
-// cz: A cctz::time_zone
 // tz: An absl::TimeZone
+// ci: An absl::TimeZone::CivilInfo
+// ti: An absl::TimeZone::TimeInfo
+// cd: An absl::CivilDay or a cctz::civil_day
+// cs: An absl::CivilSecond or a cctz::civil_second
+// bd: An absl::Time::Breakdown
 // cl: A cctz::time_zone::civil_lookup
 // al: A cctz::time_zone::absolute_lookup
-// cd: A cctz::civil_day
-// cs: A cctz::civil_second
-// bd: An absl::Time::Breakdown
 
 #include "absl/time/time.h"
 
@@ -41,12 +42,12 @@
 
 namespace cctz = absl::time_internal::cctz;
 namespace absl {
-inline namespace lts_2018_06_20 {
+inline namespace lts_2018_12_18 {
 
 namespace {
 
-inline cctz::time_point<cctz::sys_seconds> unix_epoch() {
-  return std::chrono::time_point_cast<cctz::sys_seconds>(
+inline cctz::time_point<cctz::seconds> unix_epoch() {
+  return std::chrono::time_point_cast<cctz::seconds>(
       std::chrono::system_clock::from_time_t(0));
 }
 
@@ -76,7 +77,7 @@ inline absl::Time::Breakdown InfiniteFutureBreakdown() {
   return bd;
 }
 
-inline Time::Breakdown InfinitePastBreakdown() {
+inline absl::Time::Breakdown InfinitePastBreakdown() {
   Time::Breakdown bd;
   bd.year = std::numeric_limits<int64_t>::min();
   bd.month = 1;
@@ -93,6 +94,26 @@ inline Time::Breakdown InfinitePastBreakdown() {
   return bd;
 }
 
+inline absl::TimeZone::CivilInfo InfiniteFutureCivilInfo() {
+  TimeZone::CivilInfo ci;
+  ci.cs = CivilSecond::max();
+  ci.subsecond = InfiniteDuration();
+  ci.offset = 0;
+  ci.is_dst = false;
+  ci.zone_abbr = "-00";
+  return ci;
+}
+
+inline absl::TimeZone::CivilInfo InfinitePastCivilInfo() {
+  TimeZone::CivilInfo ci;
+  ci.cs = CivilSecond::min();
+  ci.subsecond = -InfiniteDuration();
+  ci.offset = 0;
+  ci.is_dst = false;
+  ci.zone_abbr = "-00";
+  return ci;
+}
+
 inline absl::TimeConversion InfiniteFutureTimeConversion() {
   absl::TimeConversion tc;
   tc.pre = tc.trans = tc.post = absl::InfiniteFuture();
@@ -111,12 +132,12 @@ inline TimeConversion InfinitePastTimeConversion() {
 
 // Makes a Time from sec, overflowing to InfiniteFuture/InfinitePast as
 // necessary. If sec is min/max, then consult cs+tz to check for overlow.
-Time MakeTimeWithOverflow(const cctz::time_point<cctz::sys_seconds>& sec,
+Time MakeTimeWithOverflow(const cctz::time_point<cctz::seconds>& sec,
                           const cctz::civil_second& cs,
                           const cctz::time_zone& tz,
                           bool* normalized = nullptr) {
-  const auto max = cctz::time_point<cctz::sys_seconds>::max();
-  const auto min = cctz::time_point<cctz::sys_seconds>::min();
+  const auto max = cctz::time_point<cctz::seconds>::max();
+  const auto min = cctz::time_point<cctz::seconds>::min();
   if (sec == max) {
     const auto al = tz.lookup(max);
     if (cs > al.cs) {
@@ -135,19 +156,6 @@ Time MakeTimeWithOverflow(const cctz::time_point<cctz::sys_seconds>& sec,
   return time_internal::FromUnixDuration(time_internal::MakeDuration(hi));
 }
 
-inline absl::TimeConversion::Kind MapKind(
-    const cctz::time_zone::civil_lookup::civil_kind& kind) {
-  switch (kind) {
-    case cctz::time_zone::civil_lookup::UNIQUE:
-      return absl::TimeConversion::UNIQUE;
-    case cctz::time_zone::civil_lookup::SKIPPED:
-      return absl::TimeConversion::SKIPPED;
-    case cctz::time_zone::civil_lookup::REPEATED:
-      return absl::TimeConversion::REPEATED;
-  }
-  return absl::TimeConversion::UNIQUE;
-}
-
 // Returns Mon=1..Sun=7.
 inline int MapWeekday(const cctz::weekday& wd) {
   switch (wd) {
@@ -169,14 +177,31 @@ inline int MapWeekday(const cctz::weekday& wd) {
   return 1;
 }
 
+bool FindTransition(const cctz::time_zone& tz,
+                    bool (cctz::time_zone::*find_transition)(
+                        const cctz::time_point<cctz::seconds>& tp,
+                        cctz::time_zone::civil_transition* trans) const,
+                    Time t, TimeZone::CivilTransition* trans) {
+  // Transitions are second-aligned, so we can discard any fractional part.
+  const auto tp = unix_epoch() + cctz::seconds(ToUnixSeconds(t));
+  cctz::time_zone::civil_transition tr;
+  if (!(tz.*find_transition)(tp, &tr)) return false;
+  trans->from = CivilSecond(tr.from);
+  trans->to = CivilSecond(tr.to);
+  return true;
+}
+
 }  // namespace
 
+//
+// Time
+//
+
 absl::Time::Breakdown Time::In(absl::TimeZone tz) const {
-  if (*this == absl::InfiniteFuture()) return absl::InfiniteFutureBreakdown();
-  if (*this == absl::InfinitePast()) return absl::InfinitePastBreakdown();
+  if (*this == absl::InfiniteFuture()) return InfiniteFutureBreakdown();
+  if (*this == absl::InfinitePast()) return InfinitePastBreakdown();
 
-  const auto tp =
-      unix_epoch() + cctz::sys_seconds(time_internal::GetRepHi(rep_));
+  const auto tp = unix_epoch() + cctz::seconds(time_internal::GetRepHi(rep_));
   const auto al = cctz::time_zone(tz).lookup(tp);
   const auto cs = al.cs;
   const auto cd = cctz::civil_day(cs);
@@ -189,92 +214,18 @@ absl::Time::Breakdown Time::In(absl::TimeZone tz) const {
   bd.minute = cs.minute();
   bd.second = cs.second();
   bd.subsecond = time_internal::MakeDuration(0, time_internal::GetRepLo(rep_));
-  bd.weekday = MapWeekday(get_weekday(cd));
-  bd.yearday = get_yearday(cd);
+  bd.weekday = MapWeekday(cctz::get_weekday(cd));
+  bd.yearday = cctz::get_yearday(cd);
   bd.offset = al.offset;
   bd.is_dst = al.is_dst;
   bd.zone_abbr = al.abbr;
   return bd;
 }
 
-absl::Time FromTM(const struct tm& tm, absl::TimeZone tz) {
-  const auto cz = cctz::time_zone(tz);
-  const auto cs =
-      cctz::civil_second(tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday,
-                         tm.tm_hour, tm.tm_min, tm.tm_sec);
-  const auto cl = cz.lookup(cs);
-  const auto tp = tm.tm_isdst == 0 ? cl.post : cl.pre;
-  return MakeTimeWithOverflow(tp, cs, cz);
-}
-
-struct tm ToTM(absl::Time t, absl::TimeZone tz) {
-  const absl::Time::Breakdown bd = t.In(tz);
-  struct tm tm;
-  std::memset(&tm, 0, sizeof(tm));
-  tm.tm_sec = bd.second;
-  tm.tm_min = bd.minute;
-  tm.tm_hour = bd.hour;
-  tm.tm_mday = bd.day;
-  tm.tm_mon = bd.month - 1;
-
-  // Saturates tm.tm_year in cases of over/underflow, accounting for the fact
-  // that tm.tm_year is years since 1900.
-  if (bd.year < std::numeric_limits<int>::min() + 1900) {
-    tm.tm_year = std::numeric_limits<int>::min();
-  } else if (bd.year > std::numeric_limits<int>::max()) {
-    tm.tm_year = std::numeric_limits<int>::max() - 1900;
-  } else {
-    tm.tm_year = static_cast<int>(bd.year - 1900);
-  }
-
-  tm.tm_wday = bd.weekday % 7;
-  tm.tm_yday = bd.yearday - 1;
-  tm.tm_isdst = bd.is_dst ? 1 : 0;
-
-  return tm;
-}
-
 //
-// Factory functions.
+// Conversions from/to other time types.
 //
 
-absl::TimeConversion ConvertDateTime(int64_t year, int mon, int day, int hour,
-                                     int min, int sec, TimeZone tz) {
-  // Avoids years that are too extreme for civil_second to normalize.
-  if (year > 300000000000) return InfiniteFutureTimeConversion();
-  if (year < -300000000000) return InfinitePastTimeConversion();
-  const auto cz = cctz::time_zone(tz);
-  const auto cs = cctz::civil_second(year, mon, day, hour, min, sec);
-  absl::TimeConversion tc;
-  tc.normalized = year != cs.year() || mon != cs.month() || day != cs.day() ||
-                  hour != cs.hour() || min != cs.minute() || sec != cs.second();
-  const auto cl = cz.lookup(cs);
-  // Converts the civil_lookup struct to a TimeConversion.
-  tc.pre = MakeTimeWithOverflow(cl.pre, cs, cz, &tc.normalized);
-  tc.trans = MakeTimeWithOverflow(cl.trans, cs, cz, &tc.normalized);
-  tc.post = MakeTimeWithOverflow(cl.post, cs, cz, &tc.normalized);
-  tc.kind = MapKind(cl.kind);
-  return tc;
-}
-
-absl::Time FromDateTime(int64_t year, int mon, int day, int hour, int min,
-                        int sec, TimeZone tz) {
-  if (year > 300000000000) return InfiniteFuture();
-  if (year < -300000000000) return InfinitePast();
-  const auto cz = cctz::time_zone(tz);
-  const auto cs = cctz::civil_second(year, mon, day, hour, min, sec);
-  const auto cl = cz.lookup(cs);
-  return MakeTimeWithOverflow(cl.pre, cs, cz);
-}
-
-absl::Time TimeFromTimespec(timespec ts) {
-  return time_internal::FromUnixDuration(absl::DurationFromTimespec(ts));
-}
-
-absl::Time TimeFromTimeval(timeval tv) {
-  return time_internal::FromUnixDuration(absl::DurationFromTimeval(tv));
-}
-
 absl::Time FromUDate(double udate) {
   return time_internal::FromUnixDuration(absl::Milliseconds(udate));
 }
@@ -283,10 +234,6 @@ absl::Time FromUniversal(int64_t universal) {
   return absl::UniversalEpoch() + 100 * absl::Nanoseconds(universal);
 }
 
-//
-// Conversion to other time types.
-//
-
 int64_t ToUnixNanos(Time t) {
   if (time_internal::GetRepHi(time_internal::ToUnixDuration(t)) >= 0 &&
       time_internal::GetRepHi(time_internal::ToUnixDuration(t)) >> 33 == 0) {
@@ -323,6 +270,23 @@ int64_t ToUnixSeconds(Time t) {
 
 time_t ToTimeT(Time t) { return absl::ToTimespec(t).tv_sec; }
 
+double ToUDate(Time t) {
+  return absl::FDivDuration(time_internal::ToUnixDuration(t),
+                            absl::Milliseconds(1));
+}
+
+int64_t ToUniversal(absl::Time t) {
+  return absl::FloorToUnit(t - absl::UniversalEpoch(), absl::Nanoseconds(100));
+}
+
+absl::Time TimeFromTimespec(timespec ts) {
+  return time_internal::FromUnixDuration(absl::DurationFromTimespec(ts));
+}
+
+absl::Time TimeFromTimeval(timeval tv) {
+  return time_internal::FromUnixDuration(absl::DurationFromTimeval(tv));
+}
+
 timespec ToTimespec(Time t) {
   timespec ts;
   absl::Duration d = time_internal::ToUnixDuration(t);
@@ -361,15 +325,6 @@ timeval ToTimeval(Time t) {
   return tv;
 }
 
-double ToUDate(Time t) {
-  return absl::FDivDuration(time_internal::ToUnixDuration(t),
-                            absl::Milliseconds(1));
-}
-
-int64_t ToUniversal(absl::Time t) {
-  return absl::FloorToUnit(t - absl::UniversalEpoch(), absl::Nanoseconds(100));
-}
-
 Time FromChrono(const std::chrono::system_clock::time_point& tp) {
   return time_internal::FromUnixDuration(time_internal::FromChrono(
       tp - std::chrono::system_clock::from_time_t(0)));
@@ -383,5 +338,150 @@ std::chrono::system_clock::time_point ToChronoTime(absl::Time t) {
          time_internal::ToChronoDuration<D>(d);
 }
 
-}  // inline namespace lts_2018_06_20
+//
+// TimeZone
+//
+
+absl::TimeZone::CivilInfo TimeZone::At(Time t) const {
+  if (t == absl::InfiniteFuture()) return InfiniteFutureCivilInfo();
+  if (t == absl::InfinitePast()) return InfinitePastCivilInfo();
+
+  const auto ud = time_internal::ToUnixDuration(t);
+  const auto tp = unix_epoch() + cctz::seconds(time_internal::GetRepHi(ud));
+  const auto al = cz_.lookup(tp);
+
+  TimeZone::CivilInfo ci;
+  ci.cs = CivilSecond(al.cs);
+  ci.subsecond = time_internal::MakeDuration(0, time_internal::GetRepLo(ud));
+  ci.offset = al.offset;
+  ci.is_dst = al.is_dst;
+  ci.zone_abbr = al.abbr;
+  return ci;
+}
+
+absl::TimeZone::TimeInfo TimeZone::At(CivilSecond ct) const {
+  const cctz::civil_second cs(ct);
+  const auto cl = cz_.lookup(cs);
+
+  TimeZone::TimeInfo ti;
+  switch (cl.kind) {
+    case cctz::time_zone::civil_lookup::UNIQUE:
+      ti.kind = TimeZone::TimeInfo::UNIQUE;
+      break;
+    case cctz::time_zone::civil_lookup::SKIPPED:
+      ti.kind = TimeZone::TimeInfo::SKIPPED;
+      break;
+    case cctz::time_zone::civil_lookup::REPEATED:
+      ti.kind = TimeZone::TimeInfo::REPEATED;
+      break;
+  }
+  ti.pre = MakeTimeWithOverflow(cl.pre, cs, cz_);
+  ti.trans = MakeTimeWithOverflow(cl.trans, cs, cz_);
+  ti.post = MakeTimeWithOverflow(cl.post, cs, cz_);
+  return ti;
+}
+
+bool TimeZone::NextTransition(Time t, CivilTransition* trans) const {
+  return FindTransition(cz_, &cctz::time_zone::next_transition, t, trans);
+}
+
+bool TimeZone::PrevTransition(Time t, CivilTransition* trans) const {
+  return FindTransition(cz_, &cctz::time_zone::prev_transition, t, trans);
+}
+
+//
+// Conversions involving time zones.
+//
+
+absl::TimeConversion ConvertDateTime(int64_t year, int mon, int day, int hour,
+                                     int min, int sec, TimeZone tz) {
+  // Avoids years that are too extreme for CivilSecond to normalize.
+  if (year > 300000000000) return InfiniteFutureTimeConversion();
+  if (year < -300000000000) return InfinitePastTimeConversion();
+
+  const CivilSecond cs(year, mon, day, hour, min, sec);
+  const auto ti = tz.At(cs);
+
+  TimeConversion tc;
+  tc.pre = ti.pre;
+  tc.trans = ti.trans;
+  tc.post = ti.post;
+  switch (ti.kind) {
+    case TimeZone::TimeInfo::UNIQUE:
+      tc.kind = TimeConversion::UNIQUE;
+      break;
+    case TimeZone::TimeInfo::SKIPPED:
+      tc.kind = TimeConversion::SKIPPED;
+      break;
+    case TimeZone::TimeInfo::REPEATED:
+      tc.kind = TimeConversion::REPEATED;
+      break;
+  }
+  tc.normalized = false;
+  if (year != cs.year() || mon != cs.month() || day != cs.day() ||
+      hour != cs.hour() || min != cs.minute() || sec != cs.second()) {
+    tc.normalized = true;
+  }
+  return tc;
+}
+
+absl::Time FromTM(const struct tm& tm, absl::TimeZone tz) {
+  const CivilSecond cs(tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday,
+                       tm.tm_hour, tm.tm_min, tm.tm_sec);
+  const auto ti = tz.At(cs);
+  return tm.tm_isdst == 0 ? ti.post : ti.pre;
+}
+
+struct tm ToTM(absl::Time t, absl::TimeZone tz) {
+  struct tm tm = {};
+
+  const auto ci = tz.At(t);
+  const auto& cs = ci.cs;
+  tm.tm_sec = cs.second();
+  tm.tm_min = cs.minute();
+  tm.tm_hour = cs.hour();
+  tm.tm_mday = cs.day();
+  tm.tm_mon = cs.month() - 1;
+
+  // Saturates tm.tm_year in cases of over/underflow, accounting for the fact
+  // that tm.tm_year is years since 1900.
+  if (cs.year() < std::numeric_limits<int>::min() + 1900) {
+    tm.tm_year = std::numeric_limits<int>::min();
+  } else if (cs.year() > std::numeric_limits<int>::max()) {
+    tm.tm_year = std::numeric_limits<int>::max() - 1900;
+  } else {
+    tm.tm_year = static_cast<int>(cs.year() - 1900);
+  }
+
+  const CivilDay cd(cs);
+  switch (GetWeekday(cd)) {
+    case Weekday::sunday:
+      tm.tm_wday = 0;
+      break;
+    case Weekday::monday:
+      tm.tm_wday = 1;
+      break;
+    case Weekday::tuesday:
+      tm.tm_wday = 2;
+      break;
+    case Weekday::wednesday:
+      tm.tm_wday = 3;
+      break;
+    case Weekday::thursday:
+      tm.tm_wday = 4;
+      break;
+    case Weekday::friday:
+      tm.tm_wday = 5;
+      break;
+    case Weekday::saturday:
+      tm.tm_wday = 6;
+      break;
+  }
+  tm.tm_yday = GetYearDay(cd) - 1;
+  tm.tm_isdst = ci.is_dst ? 1 : 0;
+
+  return tm;
+}
+
+}  // inline namespace lts_2018_12_18
 }  // namespace absl