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// Copyright 2017 The Abseil Authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
// The implementation of the absl::Time class, which is declared in
// //absl/time.h.
//
// The representation for an absl::Time is an absl::Duration offset from the
// epoch. We use the traditional Unix epoch (1970-01-01 00:00:00 +0000)
// for convenience, but this is not exposed in the API and could be changed.
//
// NOTE: To keep type verbosity to a minimum, the following variable naming
// conventions are used throughout this file.
//
// 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
#include "absl/time/time.h"
#include <cstring>
#include <ctime>
#include <limits>
#include "absl/time/internal/cctz/include/cctz/civil_time.h"
#include "absl/time/internal/cctz/include/cctz/time_zone.h"
namespace cctz = absl::time_internal::cctz;
namespace absl {
namespace {
inline cctz::time_point<cctz::seconds> unix_epoch() {
return std::chrono::time_point_cast<cctz::seconds>(
std::chrono::system_clock::from_time_t(0));
}
// Floors d to the next unit boundary closer to negative infinity.
inline int64_t FloorToUnit(absl::Duration d, absl::Duration unit) {
absl::Duration rem;
int64_t q = absl::IDivDuration(d, unit, &rem);
return (q > 0 ||
rem >= ZeroDuration() ||
q == std::numeric_limits<int64_t>::min()) ? q : q - 1;
}
inline absl::Time::Breakdown InfiniteFutureBreakdown() {
absl::Time::Breakdown bd;
bd.year = std::numeric_limits<int64_t>::max();
bd.month = 12;
bd.day = 31;
bd.hour = 23;
bd.minute = 59;
bd.second = 59;
bd.subsecond = absl::InfiniteDuration();
bd.weekday = 4;
bd.yearday = 365;
bd.offset = 0;
bd.is_dst = false;
bd.zone_abbr = "-00";
return bd;
}
inline absl::Time::Breakdown InfinitePastBreakdown() {
Time::Breakdown bd;
bd.year = std::numeric_limits<int64_t>::min();
bd.month = 1;
bd.day = 1;
bd.hour = 0;
bd.minute = 0;
bd.second = 0;
bd.subsecond = -absl::InfiniteDuration();
bd.weekday = 7;
bd.yearday = 1;
bd.offset = 0;
bd.is_dst = false;
bd.zone_abbr = "-00";
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();
tc.kind = absl::TimeConversion::UNIQUE;
tc.normalized = true;
return tc;
}
inline TimeConversion InfinitePastTimeConversion() {
absl::TimeConversion tc;
tc.pre = tc.trans = tc.post = absl::InfinitePast();
tc.kind = absl::TimeConversion::UNIQUE;
tc.normalized = true;
return tc;
}
// 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::seconds>& sec,
const cctz::civil_second& cs,
const cctz::time_zone& tz,
bool* normalized = nullptr) {
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) {
if (normalized) *normalized = true;
return absl::InfiniteFuture();
}
}
if (sec == min) {
const auto al = tz.lookup(min);
if (cs < al.cs) {
if (normalized) *normalized = true;
return absl::InfinitePast();
}
}
const auto hi = (sec - unix_epoch()).count();
return time_internal::FromUnixDuration(time_internal::MakeDuration(hi));
}
// Returns Mon=1..Sun=7.
inline int MapWeekday(const cctz::weekday& wd) {
switch (wd) {
case cctz::weekday::monday:
return 1;
case cctz::weekday::tuesday:
return 2;
case cctz::weekday::wednesday:
return 3;
case cctz::weekday::thursday:
return 4;
case cctz::weekday::friday:
return 5;
case cctz::weekday::saturday:
return 6;
case cctz::weekday::sunday:
return 7;
}
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 InfiniteFutureBreakdown();
if (*this == absl::InfinitePast()) return InfinitePastBreakdown();
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);
absl::Time::Breakdown bd;
bd.year = cs.year();
bd.month = cs.month();
bd.day = cs.day();
bd.hour = cs.hour();
bd.minute = cs.minute();
bd.second = cs.second();
bd.subsecond = time_internal::MakeDuration(0, time_internal::GetRepLo(rep_));
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;
}
//
// Conversions from/to other time types.
//
absl::Time FromUDate(double udate) {
return time_internal::FromUnixDuration(absl::Milliseconds(udate));
}
absl::Time FromUniversal(int64_t universal) {
return absl::UniversalEpoch() + 100 * absl::Nanoseconds(universal);
}
int64_t ToUnixNanos(Time t) {
if (time_internal::GetRepHi(time_internal::ToUnixDuration(t)) >= 0 &&
time_internal::GetRepHi(time_internal::ToUnixDuration(t)) >> 33 == 0) {
return (time_internal::GetRepHi(time_internal::ToUnixDuration(t)) *
1000 * 1000 * 1000) +
(time_internal::GetRepLo(time_internal::ToUnixDuration(t)) / 4);
}
return FloorToUnit(time_internal::ToUnixDuration(t), absl::Nanoseconds(1));
}
int64_t ToUnixMicros(Time t) {
if (time_internal::GetRepHi(time_internal::ToUnixDuration(t)) >= 0 &&
time_internal::GetRepHi(time_internal::ToUnixDuration(t)) >> 43 == 0) {
return (time_internal::GetRepHi(time_internal::ToUnixDuration(t)) *
1000 * 1000) +
(time_internal::GetRepLo(time_internal::ToUnixDuration(t)) / 4000);
}
return FloorToUnit(time_internal::ToUnixDuration(t), absl::Microseconds(1));
}
int64_t ToUnixMillis(Time t) {
if (time_internal::GetRepHi(time_internal::ToUnixDuration(t)) >= 0 &&
time_internal::GetRepHi(time_internal::ToUnixDuration(t)) >> 53 == 0) {
return (time_internal::GetRepHi(time_internal::ToUnixDuration(t)) * 1000) +
(time_internal::GetRepLo(time_internal::ToUnixDuration(t)) /
(4000 * 1000));
}
return FloorToUnit(time_internal::ToUnixDuration(t), absl::Milliseconds(1));
}
int64_t ToUnixSeconds(Time t) {
return time_internal::GetRepHi(time_internal::ToUnixDuration(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);
if (!time_internal::IsInfiniteDuration(d)) {
ts.tv_sec = time_internal::GetRepHi(d);
if (ts.tv_sec == time_internal::GetRepHi(d)) { // no time_t narrowing
ts.tv_nsec = time_internal::GetRepLo(d) / 4; // floor
return ts;
}
}
if (d >= absl::ZeroDuration()) {
ts.tv_sec = std::numeric_limits<time_t>::max();
ts.tv_nsec = 1000 * 1000 * 1000 - 1;
} else {
ts.tv_sec = std::numeric_limits<time_t>::min();
ts.tv_nsec = 0;
}
return ts;
}
timeval ToTimeval(Time t) {
timeval tv;
timespec ts = absl::ToTimespec(t);
tv.tv_sec = ts.tv_sec;
if (tv.tv_sec != ts.tv_sec) { // narrowing
if (ts.tv_sec < 0) {
tv.tv_sec = std::numeric_limits<decltype(tv.tv_sec)>::min();
tv.tv_usec = 0;
} else {
tv.tv_sec = std::numeric_limits<decltype(tv.tv_sec)>::max();
tv.tv_usec = 1000 * 1000 - 1;
}
return tv;
}
tv.tv_usec = static_cast<int>(ts.tv_nsec / 1000); // suseconds_t
return tv;
}
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)));
}
std::chrono::system_clock::time_point ToChronoTime(absl::Time t) {
using D = std::chrono::system_clock::duration;
auto d = time_internal::ToUnixDuration(t);
if (d < ZeroDuration()) d = Floor(d, FromChrono(D{1}));
return std::chrono::system_clock::from_time_t(0) +
time_internal::ToChronoDuration<D>(d);
}
//
// 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;
}
} // namespace absl