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- fd5f3d7077270ffc5ea74cdb9e18bbae3b9b46aa Fix typo optional -> variant by Abseil Team <absl-team@google.com>

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- 9136c06dfa8dbfdde0a427ad3509e34763d607a6 Fix string_view_test and str_cat_test build under MSVC de... by Derek Mauro <dmauro@google.com>
  - a463820f9441888f4368aa87328599e3209f9b07 Removes constexpr optional<T>::operator->(). This was don... by Abseil Team <absl-team@google.com>
  - 3bf78a7f126daafff329f7815d507422f1ca378d Remove dependencies on external CCTZ project. by Shaindel Schwartz <shaindel@google.com>
  - a4ae574a11b1ddf6e88459af3d638cf79aea7ecd Internal change by Jon Cohen <cohenjon@google.com>

GitOrigin-RevId: fd5f3d7077270ffc5ea74cdb9e18bbae3b9b46aa
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// Copyright 2016 Google Inc. All Rights Reserved.
//
// 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.
#ifndef ABSL_TIME_INTERNAL_CCTZ_CIVIL_TIME_H_
#define ABSL_TIME_INTERNAL_CCTZ_CIVIL_TIME_H_
#include "absl/time/internal/cctz/include/cctz/civil_time_detail.h"
namespace absl {
namespace time_internal {
namespace cctz {
// The term "civil time" refers to the legally recognized human-scale time
// that is represented by the six fields YYYY-MM-DD hh:mm:ss. Modern-day civil
// time follows the Gregorian Calendar and is a time-zone-independent concept.
// A "date" is perhaps the most common example of a civil time (represented in
// this library as cctz::civil_day). This library provides six classes and a
// handful of functions that help with rounding, iterating, and arithmetic on
// civil times while avoiding complications like daylight-saving time (DST).
//
// The following six classes form the core of this civil-time library:
//
// * civil_second
// * civil_minute
// * civil_hour
// * civil_day
// * civil_month
// * civil_year
//
// Each class is a simple value type with the same interface for construction
// and the same six accessors for each of the civil fields (year, month, day,
// hour, minute, and second, aka YMDHMS). These classes differ only in their
// alignment, which is indicated by the type name and specifies the field on
// which arithmetic operates.
//
// Each class can be constructed by passing up to six optional integer
// arguments representing the YMDHMS fields (in that order) to the
// constructor. Omitted fields are assigned their minimum valid value. Hours,
// minutes, and seconds will be set to 0, month and day will be set to 1, and
// since there is no minimum valid year, it will be set to 1970. So, a
// default-constructed civil-time object will have YMDHMS fields representing
// "1970-01-01 00:00:00". Fields that are out-of-range are normalized (e.g.,
// October 32 -> November 1) so that all civil-time objects represent valid
// values.
//
// Each civil-time class is aligned to the civil-time field indicated in the
// class's name after normalization. Alignment is performed by setting all the
// inferior fields to their minimum valid value (as described above). The
// following are examples of how each of the six types would align the fields
// representing November 22, 2015 at 12:34:56 in the afternoon. (Note: the
// std::string format used here is not important; it's just a shorthand way of
// showing the six YMDHMS fields.)
//
// civil_second 2015-11-22 12:34:56
// civil_minute 2015-11-22 12:34:00
// civil_hour 2015-11-22 12:00:00
// civil_day 2015-11-22 00:00:00
// civil_month 2015-11-01 00:00:00
// civil_year 2015-01-01 00:00:00
//
// Each civil-time type performs arithmetic on the field to which it is
// aligned. This means that adding 1 to a civil_day increments the day field
// (normalizing as necessary), and subtracting 7 from a civil_month operates
// on the month field (normalizing as necessary). All arithmetic produces a
// valid civil time. Difference requires two similarly aligned civil-time
// objects and returns the scalar answer in units of the objects' alignment.
// For example, the difference between two civil_hour objects will give an
// answer in units of civil hours.
//
// In addition to the six civil-time types just described, there are
// a handful of helper functions and algorithms for performing common
// calculations. These are described below.
//
// Note: In C++14 and later, this library is usable in a constexpr context.
//
// CONSTRUCTION:
//
// Each of the civil-time types can be constructed in two ways: by directly
// passing to the constructor up to six (optional) integers representing the
// YMDHMS fields, or by copying the YMDHMS fields from a differently aligned
// civil-time type.
//
// civil_day default_value; // 1970-01-01 00:00:00
//
// civil_day a(2015, 2, 3); // 2015-02-03 00:00:00
// civil_day b(2015, 2, 3, 4, 5, 6); // 2015-02-03 00:00:00
// civil_day c(2015); // 2015-01-01 00:00:00
//
// civil_second ss(2015, 2, 3, 4, 5, 6); // 2015-02-03 04:05:06
// civil_minute mm(ss); // 2015-02-03 04:05:00
// civil_hour hh(mm); // 2015-02-03 04:00:00
// civil_day d(hh); // 2015-02-03 00:00:00
// civil_month m(d); // 2015-02-01 00:00:00
// civil_year y(m); // 2015-01-01 00:00:00
//
// m = civil_month(y); // 2015-01-01 00:00:00
// d = civil_day(m); // 2015-01-01 00:00:00
// hh = civil_hour(d); // 2015-01-01 00:00:00
// mm = civil_minute(hh); // 2015-01-01 00:00:00
// ss = civil_second(mm); // 2015-01-01 00:00:00
//
// ALIGNMENT CONVERSION:
//
// The alignment of a civil-time object cannot change, but the object may be
// used to construct a new object with a different alignment. This is referred
// to as "realigning". When realigning to a type with the same or more
// precision (e.g., civil_day -> civil_second), the conversion may be
// performed implicitly since no information is lost. However, if information
// could be discarded (e.g., civil_second -> civil_day), the conversion must
// be explicit at the call site.
//
// void fun(const civil_day& day);
//
// civil_second cs;
// fun(cs); // Won't compile because data may be discarded
// fun(civil_day(cs)); // OK: explicit conversion
//
// civil_day cd;
// fun(cd); // OK: no conversion needed
//
// civil_month cm;
// fun(cm); // OK: implicit conversion to civil_day
//
// NORMALIZATION:
//
// Integer arguments passed to the constructor may be out-of-range, in which
// case they are normalized to produce a valid civil-time object. This enables
// natural arithmetic on constructor arguments without worrying about the
// field's range. Normalization guarantees that there are no invalid
// civil-time objects.
//
// civil_day d(2016, 10, 32); // Out-of-range day; normalized to 2016-11-01
//
// Note: If normalization is undesired, you can signal an error by comparing
// the constructor arguments to the normalized values returned by the YMDHMS
// properties.
//
// PROPERTIES:
//
// All civil-time types have accessors for all six of the civil-time fields:
// year, month, day, hour, minute, and second. Recall that fields inferior to
// the type's aligment will be set to their minimum valid value.
//
// civil_day d(2015, 6, 28);
// // d.year() == 2015
// // d.month() == 6
// // d.day() == 28
// // d.hour() == 0
// // d.minute() == 0
// // d.second() == 0
//
// COMPARISON:
//
// Comparison always considers all six YMDHMS fields, regardless of the type's
// alignment. Comparison between differently aligned civil-time types is
// allowed.
//
// civil_day feb_3(2015, 2, 3); // 2015-02-03 00:00:00
// civil_day mar_4(2015, 3, 4); // 2015-03-04 00:00:00
// // feb_3 < mar_4
// // civil_year(feb_3) == civil_year(mar_4)
//
// civil_second feb_3_noon(2015, 2, 3, 12, 0, 0); // 2015-02-03 12:00:00
// // feb_3 < feb_3_noon
// // feb_3 == civil_day(feb_3_noon)
//
// // Iterates all the days of February 2015.
// for (civil_day d(2015, 2, 1); d < civil_month(2015, 3); ++d) {
// // ...
// }
//
// STREAMING:
//
// Each civil-time type may be sent to an output stream using operator<<().
// The output format follows the pattern "YYYY-MM-DDThh:mm:ss" where fields
// inferior to the type's alignment are omitted.
//
// civil_second cs(2015, 2, 3, 4, 5, 6);
// std::cout << cs << "\n"; // Outputs: 2015-02-03T04:05:06
//
// civil_day cd(cs);
// std::cout << cd << "\n"; // Outputs: 2015-02-03
//
// civil_year cy(cs);
// std::cout << cy << "\n"; // Outputs: 2015
//
// ARITHMETIC:
//
// Civil-time types support natural arithmetic operators such as addition,
// subtraction, and difference. Arithmetic operates on the civil-time field
// indicated in the type's name. Difference requires arguments with the same
// alignment and returns the answer in units of the alignment.
//
// civil_day a(2015, 2, 3);
// ++a; // 2015-02-04 00:00:00
// --a; // 2015-02-03 00:00:00
// civil_day b = a + 1; // 2015-02-04 00:00:00
// civil_day c = 1 + b; // 2015-02-05 00:00:00
// int n = c - a; // n = 2 (civil days)
// int m = c - civil_month(c); // Won't compile: different types.
//
// EXAMPLE: Adding a month to January 31.
//
// One of the classic questions that arises when considering a civil-time
// library (or a date library or a date/time library) is this: "What happens
// when you add a month to January 31?" This is an interesting question
// because there could be a number of possible answers:
//
// 1. March 3 (or 2 if a leap year). This may make sense if the operation
// wants the equivalent of February 31.
// 2. February 28 (or 29 if a leap year). This may make sense if the operation
// wants the last day of January to go to the last day of February.
// 3. Error. The caller may get some error, an exception, an invalid date
// object, or maybe false is returned. This may make sense because there is
// no single unambiguously correct answer to the question.
//
// Practically speaking, any answer that is not what the programmer intended
// is the wrong answer.
//
// This civil-time library avoids the problem by making it impossible to ask
// ambiguous questions. All civil-time objects are aligned to a particular
// civil-field boundary (such as aligned to a year, month, day, hour, minute,
// or second), and arithmetic operates on the field to which the object is
// aligned. This means that in order to "add a month" the object must first be
// aligned to a month boundary, which is equivalent to the first day of that
// month.
//
// Of course, there are ways to compute an answer the question at hand using
// this civil-time library, but they require the programmer to be explicit
// about the answer they expect. To illustrate, let's see how to compute all
// three of the above possible answers to the question of "Jan 31 plus 1
// month":
//
// const civil_day d(2015, 1, 31);
//
// // Answer 1:
// // Add 1 to the month field in the constructor, and rely on normalization.
// const auto ans_normalized = civil_day(d.year(), d.month() + 1, d.day());
// // ans_normalized == 2015-03-03 (aka Feb 31)
//
// // Answer 2:
// // Add 1 to month field, capping to the end of next month.
// const auto next_month = civil_month(d) + 1;
// const auto last_day_of_next_month = civil_day(next_month + 1) - 1;
// const auto ans_capped = std::min(ans_normalized, last_day_of_next_month);
// // ans_capped == 2015-02-28
//
// // Answer 3:
// // Signal an error if the normalized answer is not in next month.
// if (civil_month(ans_normalized) != next_month) {
// // error, month overflow
// }
//
using civil_year = detail::civil_year;
using civil_month = detail::civil_month;
using civil_day = detail::civil_day;
using civil_hour = detail::civil_hour;
using civil_minute = detail::civil_minute;
using civil_second = detail::civil_second;
// An enum class with members monday, tuesday, wednesday, thursday, friday,
// saturday, and sunday. These enum values may be sent to an output stream
// using operator<<(). The result is the full weekday name in English with a
// leading capital letter.
//
// weekday wd = weekday::thursday;
// std::cout << wd << "\n"; // Outputs: Thursday
//
using detail::weekday;
// Returns the weekday for the given civil_day.
//
// civil_day a(2015, 8, 13);
// weekday wd = get_weekday(a); // wd == weekday::thursday
//
using detail::get_weekday;
// Returns the civil_day that strictly follows or precedes the given
// civil_day, and that falls on the given weekday.
//
// For example, given:
//
// August 2015
// Su Mo Tu We Th Fr Sa
// 1
// 2 3 4 5 6 7 8
// 9 10 11 12 13 14 15
// 16 17 18 19 20 21 22
// 23 24 25 26 27 28 29
// 30 31
//
// civil_day a(2015, 8, 13); // get_weekday(a) == weekday::thursday
// civil_day b = next_weekday(a, weekday::thursday); // b = 2015-08-20
// civil_day c = prev_weekday(a, weekday::thursday); // c = 2015-08-06
//
// civil_day d = ...
// // Gets the following Thursday if d is not already Thursday
// civil_day thurs1 = prev_weekday(d, weekday::thursday) + 7;
// // Gets the previous Thursday if d is not already Thursday
// civil_day thurs2 = next_weekday(d, weekday::thursday) - 7;
//
using detail::next_weekday;
using detail::prev_weekday;
// Returns the day-of-year for the given civil_day.
//
// civil_day a(2015, 1, 1);
// int yd_jan_1 = get_yearday(a); // yd_jan_1 = 1
// civil_day b(2015, 12, 31);
// int yd_dec_31 = get_yearday(b); // yd_dec_31 = 365
//
using detail::get_yearday;
} // namespace cctz
} // namespace time_internal
} // namespace absl
#endif // ABSL_TIME_INTERNAL_CCTZ_CIVIL_TIME_H_

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// Copyright 2016 Google Inc. All Rights Reserved.
//
// 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.
#ifndef ABSL_TIME_INTERNAL_CCTZ_CIVIL_TIME_DETAIL_H_
#define ABSL_TIME_INTERNAL_CCTZ_CIVIL_TIME_DETAIL_H_
#include <cstdint>
#include <limits>
#include <ostream>
#include <type_traits>
// Disable constexpr support unless we are using clang in C++14 mode.
#if __clang__ && __cpp_constexpr >= 201304
#define CONSTEXPR_D constexpr // data
#define CONSTEXPR_F constexpr // function
#define CONSTEXPR_M constexpr // member
#else
#define CONSTEXPR_D const
#define CONSTEXPR_F inline
#define CONSTEXPR_M
#endif
namespace absl {
namespace time_internal {
namespace cctz {
// Support years that at least span the range of 64-bit time_t values.
using year_t = std::int_fast64_t;
// Type alias that indicates an argument is not normalized (e.g., the
// constructor parameters and operands/results of addition/subtraction).
using diff_t = std::int_fast64_t;
namespace detail {
// Type aliases that indicate normalized argument values.
using month_t = std::int_fast8_t; // [1:12]
using day_t = std::int_fast8_t; // [1:31]
using hour_t = std::int_fast8_t; // [0:23]
using minute_t = std::int_fast8_t; // [0:59]
using second_t = std::int_fast8_t; // [0:59]
// Normalized civil-time fields: Y-M-D HH:MM:SS.
struct fields {
CONSTEXPR_M fields(year_t year, month_t month, day_t day,
hour_t hour, minute_t minute, second_t second)
: y(year), m(month), d(day), hh(hour), mm(minute), ss(second) {}
std::int_least64_t y;
std::int_least8_t m;
std::int_least8_t d;
std::int_least8_t hh;
std::int_least8_t mm;
std::int_least8_t ss;
};
struct second_tag {};
struct minute_tag : second_tag {};
struct hour_tag : minute_tag {};
struct day_tag : hour_tag {};
struct month_tag : day_tag {};
struct year_tag : month_tag {};
////////////////////////////////////////////////////////////////////////
// Field normalization (without avoidable overflow).
namespace impl {
CONSTEXPR_F bool is_leap_year(year_t y) noexcept {
return y % 4 == 0 && (y % 100 != 0 || y % 400 == 0);
}
CONSTEXPR_F int year_index(year_t y, month_t m) noexcept {
return (static_cast<int>((y + (m > 2)) % 400) + 400) % 400;
}
CONSTEXPR_F int days_per_century(year_t y, month_t m) noexcept {
const int yi = year_index(y, m);
return 36524 + (yi == 0 || yi > 300);
}
CONSTEXPR_F int days_per_4years(year_t y, month_t m) noexcept {
const int yi = year_index(y, m);
return 1460 + (yi == 0 || yi > 300 || (yi - 1) % 100 < 96);
}
CONSTEXPR_F int days_per_year(year_t y, month_t m) noexcept {
return is_leap_year(y + (m > 2)) ? 366 : 365;
}
CONSTEXPR_F int days_per_month(year_t y, month_t m) noexcept {
CONSTEXPR_D int k_days_per_month[1 + 12] = {
-1, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 // non leap year
};
return k_days_per_month[m] + (m == 2 && is_leap_year(y));
}
CONSTEXPR_F fields n_day(year_t y, month_t m, diff_t d, diff_t cd,
hour_t hh, minute_t mm, second_t ss) noexcept {
y += (cd / 146097) * 400;
cd %= 146097;
if (cd < 0) {
y -= 400;
cd += 146097;
}
y += (d / 146097) * 400;
d = d % 146097 + cd;
if (d > 0) {
if (d > 146097) {
y += 400;
d -= 146097;
}
} else {
if (d > -365) {
// We often hit the previous year when stepping a civil time backwards,
// so special case it to avoid counting up by 100/4/1-year chunks.
y -= 1;
d += days_per_year(y, m);
} else {
y -= 400;
d += 146097;
}
}
if (d > 365) {
for (int n = days_per_century(y, m); d > n; n = days_per_century(y, m)) {
d -= n;
y += 100;
}
for (int n = days_per_4years(y, m); d > n; n = days_per_4years(y, m)) {
d -= n;
y += 4;
}
for (int n = days_per_year(y, m); d > n; n = days_per_year(y, m)) {
d -= n;
++y;
}
}
if (d > 28) {
for (int n = days_per_month(y, m); d > n; n = days_per_month(y, m)) {
d -= n;
if (++m > 12) {
++y;
m = 1;
}
}
}
return fields(y, m, static_cast<day_t>(d), hh, mm, ss);
}
CONSTEXPR_F fields n_mon(year_t y, diff_t m, diff_t d, diff_t cd,
hour_t hh, minute_t mm, second_t ss) noexcept {
if (m != 12) {
y += m / 12;
m %= 12;
if (m <= 0) {
y -= 1;
m += 12;
}
}
return n_day(y, static_cast<month_t>(m), d, cd, hh, mm, ss);
}
CONSTEXPR_F fields n_hour(year_t y, diff_t m, diff_t d, diff_t cd,
diff_t hh, minute_t mm, second_t ss) noexcept {
cd += hh / 24;
hh %= 24;
if (hh < 0) {
cd -= 1;
hh += 24;
}
return n_mon(y, m, d, cd, static_cast<hour_t>(hh), mm, ss);
}
CONSTEXPR_F fields n_min(year_t y, diff_t m, diff_t d, diff_t hh, diff_t ch,
diff_t mm, second_t ss) noexcept {
ch += mm / 60;
mm %= 60;
if (mm < 0) {
ch -= 1;
mm += 60;
}
return n_hour(y, m, d, hh / 24 + ch / 24, hh % 24 + ch % 24,
static_cast<minute_t>(mm), ss);
}
CONSTEXPR_F fields n_sec(year_t y, diff_t m, diff_t d, diff_t hh, diff_t mm,
diff_t ss) noexcept {
// Optimization for when (non-constexpr) fields are already normalized.
if (0 <= ss && ss < 60) {
const second_t nss = static_cast<second_t>(ss);
if (0 <= mm && mm < 60) {
const minute_t nmm = static_cast<minute_t>(mm);
if (0 <= hh && hh < 24) {
const hour_t nhh = static_cast<hour_t>(hh);
if (1 <= d && d <= 28 && 1 <= m && m <= 12) {
const day_t nd = static_cast<day_t>(d);
const month_t nm = static_cast<month_t>(m);
return fields(y, nm, nd, nhh, nmm, nss);
}
return n_mon(y, m, d, 0, nhh, nmm, nss);
}
return n_hour(y, m, d, hh / 24, hh % 24, nmm, nss);
}
return n_min(y, m, d, hh, mm / 60, mm % 60, nss);
}
diff_t cm = ss / 60;
ss %= 60;
if (ss < 0) {
cm -= 1;
ss += 60;
}
return n_min(y, m, d, hh, mm / 60 + cm / 60, mm % 60 + cm % 60,
static_cast<second_t>(ss));
}
} // namespace impl
////////////////////////////////////////////////////////////////////////
// Increments the indicated (normalized) field by "n".
CONSTEXPR_F fields step(second_tag, fields f, diff_t n) noexcept {
return impl::n_sec(f.y, f.m, f.d, f.hh, f.mm + n / 60, f.ss + n % 60);
}
CONSTEXPR_F fields step(minute_tag, fields f, diff_t n) noexcept {
return impl::n_min(f.y, f.m, f.d, f.hh + n / 60, 0, f.mm + n % 60, f.ss);
}
CONSTEXPR_F fields step(hour_tag, fields f, diff_t n) noexcept {
return impl::n_hour(f.y, f.m, f.d + n / 24, 0, f.hh + n % 24, f.mm, f.ss);
}
CONSTEXPR_F fields step(day_tag, fields f, diff_t n) noexcept {
return impl::n_day(f.y, f.m, f.d, n, f.hh, f.mm, f.ss);
}
CONSTEXPR_F fields step(month_tag, fields f, diff_t n) noexcept {
return impl::n_mon(f.y + n / 12, f.m + n % 12, f.d, 0, f.hh, f.mm, f.ss);
}
CONSTEXPR_F fields step(year_tag, fields f, diff_t n) noexcept {
return fields(f.y + n, f.m, f.d, f.hh, f.mm, f.ss);
}
////////////////////////////////////////////////////////////////////////
namespace impl {
// Returns (v * f + a) but avoiding intermediate overflow when possible.
CONSTEXPR_F diff_t scale_add(diff_t v, diff_t f, diff_t a) noexcept {
return (v < 0) ? ((v + 1) * f + a) - f : ((v - 1) * f + a) + f;
}
// Map a (normalized) Y/M/D to the number of days before/after 1970-01-01.
// Probably overflows for years outside [-292277022656:292277026595].
CONSTEXPR_F diff_t ymd_ord(year_t y, month_t m, day_t d) noexcept {
const diff_t eyear = (m <= 2) ? y - 1 : y;
const diff_t era = (eyear >= 0 ? eyear : eyear - 399) / 400;
const diff_t yoe = eyear - era * 400;
const diff_t doy = (153 * (m + (m > 2 ? -3 : 9)) + 2) / 5 + d - 1;
const diff_t doe = yoe * 365 + yoe / 4 - yoe / 100 + doy;
return era * 146097 + doe - 719468;
}
// Returns the difference in days between two normalized Y-M-D tuples.
// ymd_ord() will encounter integer overflow given extreme year values,
// yet the difference between two such extreme values may actually be
// small, so we take a little care to avoid overflow when possible by
// exploiting the 146097-day cycle.
CONSTEXPR_F diff_t day_difference(year_t y1, month_t m1, day_t d1,
year_t y2, month_t m2, day_t d2) noexcept {
const diff_t a_c4_off = y1 % 400;
const diff_t b_c4_off = y2 % 400;
diff_t c4_diff = (y1 - a_c4_off) - (y2 - b_c4_off);
diff_t delta = ymd_ord(a_c4_off, m1, d1) - ymd_ord(b_c4_off, m2, d2);
if (c4_diff > 0 && delta < 0) {
delta += 2 * 146097;
c4_diff -= 2 * 400;
} else if (c4_diff < 0 && delta > 0) {
delta -= 2 * 146097;
c4_diff += 2 * 400;
}
return (c4_diff / 400 * 146097) + delta;
}
} // namespace impl
// Returns the difference between fields structs using the indicated unit.
CONSTEXPR_F diff_t difference(year_tag, fields f1, fields f2) noexcept {
return f1.y - f2.y;
}
CONSTEXPR_F diff_t difference(month_tag, fields f1, fields f2) noexcept {
return impl::scale_add(difference(year_tag{}, f1, f2), 12, (f1.m - f2.m));
}
CONSTEXPR_F diff_t difference(day_tag, fields f1, fields f2) noexcept {
return impl::day_difference(f1.y, f1.m, f1.d, f2.y, f2.m, f2.d);
}
CONSTEXPR_F diff_t difference(hour_tag, fields f1, fields f2) noexcept {
return impl::scale_add(difference(day_tag{}, f1, f2), 24, (f1.hh - f2.hh));
}
CONSTEXPR_F diff_t difference(minute_tag, fields f1, fields f2) noexcept {
return impl::scale_add(difference(hour_tag{}, f1, f2), 60, (f1.mm - f2.mm));
}
CONSTEXPR_F diff_t difference(second_tag, fields f1, fields f2) noexcept {
return impl::scale_add(difference(minute_tag{}, f1, f2), 60, f1.ss - f2.ss);
}
////////////////////////////////////////////////////////////////////////
// Aligns the (normalized) fields struct to the indicated field.
CONSTEXPR_F fields align(second_tag, fields f) noexcept {
return f;
}
CONSTEXPR_F fields align(minute_tag, fields f) noexcept {
return fields{f.y, f.m, f.d, f.hh, f.mm, 0};
}
CONSTEXPR_F fields align(hour_tag, fields f) noexcept {
return fields{f.y, f.m, f.d, f.hh, 0, 0};
}
CONSTEXPR_F fields align(day_tag, fields f) noexcept {
return fields{f.y, f.m, f.d, 0, 0, 0};
}
CONSTEXPR_F fields align(month_tag, fields f) noexcept {
return fields{f.y, f.m, 1, 0, 0, 0};
}
CONSTEXPR_F fields align(year_tag, fields f) noexcept {
return fields{f.y, 1, 1, 0, 0, 0};
}
////////////////////////////////////////////////////////////////////////
template <typename T>
class civil_time {
public:
explicit CONSTEXPR_M civil_time(year_t y, diff_t m = 1, diff_t d = 1,
diff_t hh = 0, diff_t mm = 0,
diff_t ss = 0) noexcept
: civil_time(impl::n_sec(y, m, d, hh, mm, ss)) {}
CONSTEXPR_M civil_time() noexcept : f_{1970, 1, 1, 0, 0, 0} {}
civil_time(const civil_time&) = default;
civil_time& operator=(const civil_time&) = default;
// Conversion between civil times of different alignment. Conversion to
// a more precise alignment is allowed implicitly (e.g., day -> hour),
// but conversion where information is discarded must be explicit
// (e.g., second -> minute).
template <typename U, typename S>
using preserves_data =
typename std::enable_if<std::is_base_of<U, S>::value>::type;
template <typename U>
CONSTEXPR_M civil_time(const civil_time<U>& ct,
preserves_data<T, U>* = nullptr) noexcept
: civil_time(ct.f_) {}
template <typename U>
explicit CONSTEXPR_M civil_time(const civil_time<U>& ct,
preserves_data<U, T>* = nullptr) noexcept
: civil_time(ct.f_) {}
// Factories for the maximum/minimum representable civil_time.
static civil_time max() {
const auto max_year = std::numeric_limits<std::int_least64_t>::max();
return civil_time(max_year, 12, 31, 23, 59, 59);
}
static civil_time min() {
const auto min_year = std::numeric_limits<std::int_least64_t>::min();
return civil_time(min_year, 1, 1, 0, 0, 0);
}
// Field accessors. Note: All but year() return an int.
CONSTEXPR_M year_t year() const noexcept { return f_.y; }
CONSTEXPR_M int month() const noexcept { return f_.m; }
CONSTEXPR_M int day() const noexcept { return f_.d; }
CONSTEXPR_M int hour() const noexcept { return f_.hh; }
CONSTEXPR_M int minute() const noexcept { return f_.mm; }
CONSTEXPR_M int second() const noexcept { return f_.ss; }
// Assigning arithmetic.
CONSTEXPR_M civil_time& operator+=(diff_t n) noexcept {
f_ = step(T{}, f_, n);
return *this;
}
CONSTEXPR_M civil_time& operator-=(diff_t n) noexcept {
if (n != std::numeric_limits<diff_t>::min()) {
f_ = step(T{}, f_, -n);
} else {
f_ = step(T{}, step(T{}, f_, -(n + 1)), 1);
}
return *this;
}
CONSTEXPR_M civil_time& operator++() noexcept {
return *this += 1;
}
CONSTEXPR_M civil_time operator++(int) noexcept {
const civil_time a = *this;
++*this;
return a;
}
CONSTEXPR_M civil_time& operator--() noexcept {
return *this -= 1;
}
CONSTEXPR_M civil_time operator--(int) noexcept {
const civil_time a = *this;
--*this;
return a;
}
// Binary arithmetic operators.
inline friend CONSTEXPR_M civil_time operator+(civil_time a,
diff_t n) noexcept {
return a += n;
}
inline friend CONSTEXPR_M civil_time operator+(diff_t n,
civil_time a) noexcept {
return a += n;
}
inline friend CONSTEXPR_M civil_time operator-(civil_time a,
diff_t n) noexcept {
return a -= n;
}
inline friend CONSTEXPR_M diff_t operator-(const civil_time& lhs,
const civil_time& rhs) noexcept {
return difference(T{}, lhs.f_, rhs.f_);
}
private:
// All instantiations of this template are allowed to call the following
// private constructor and access the private fields member.
template <typename U>
friend class civil_time;
// The designated constructor that all others eventually call.
explicit CONSTEXPR_M civil_time(fields f) noexcept : f_(align(T{}, f)) {}
fields f_;
};
// Disallows difference between differently aligned types.
// auto n = civil_day(...) - civil_hour(...); // would be confusing.
template <typename Tag1, typename Tag2>
CONSTEXPR_F diff_t operator-(civil_time<Tag1>, civil_time<Tag2>) = delete;
using civil_year = civil_time<year_tag>;
using civil_month = civil_time<month_tag>;
using civil_day = civil_time<day_tag>;
using civil_hour = civil_time<hour_tag>;
using civil_minute = civil_time<minute_tag>;
using civil_second = civil_time<second_tag>;
////////////////////////////////////////////////////////////////////////
// Relational operators that work with differently aligned objects.
// Always compares all six fields.
template <typename T1, typename T2>
CONSTEXPR_F bool operator<(const civil_time<T1>& lhs,
const civil_time<T2>& rhs) noexcept {
return (lhs.year() < rhs.year() ||
(lhs.year() == rhs.year() &&
(lhs.month() < rhs.month() ||
(lhs.month() == rhs.month() &&
(lhs.day() < rhs.day() ||
(lhs.day() == rhs.day() &&
(lhs.hour() < rhs.hour() ||
(lhs.hour() == rhs.hour() &&
(lhs.minute() < rhs.minute() ||
(lhs.minute() == rhs.minute() &&
(lhs.second() < rhs.second())))))))))));
}
template <typename T1, typename T2>
CONSTEXPR_F bool operator<=(const civil_time<T1>& lhs,
const civil_time<T2>& rhs) noexcept {
return !(rhs < lhs);
}
template <typename T1, typename T2>
CONSTEXPR_F bool operator>=(const civil_time<T1>& lhs,
const civil_time<T2>& rhs) noexcept {
return !(lhs < rhs);
}
template <typename T1, typename T2>
CONSTEXPR_F bool operator>(const civil_time<T1>& lhs,
const civil_time<T2>& rhs) noexcept {
return rhs < lhs;
}
template <typename T1, typename T2>
CONSTEXPR_F bool operator==(const civil_time<T1>& lhs,
const civil_time<T2>& rhs) noexcept {
return lhs.year() == rhs.year() && lhs.month() == rhs.month() &&
lhs.day() == rhs.day() && lhs.hour() == rhs.hour() &&
lhs.minute() == rhs.minute() && lhs.second() == rhs.second();
}
template <typename T1, typename T2>
CONSTEXPR_F bool operator!=(const civil_time<T1>& lhs,
const civil_time<T2>& rhs) noexcept {
return !(lhs == rhs);
}
////////////////////////////////////////////////////////////////////////
enum class weekday {
monday,
tuesday,
wednesday,
thursday,
friday,
saturday,
sunday,
};
CONSTEXPR_F weekday get_weekday(const civil_day& cd) noexcept {
CONSTEXPR_D weekday k_weekday_by_sun_off[7] = {
weekday::sunday, weekday::monday, weekday::tuesday,
weekday::wednesday, weekday::thursday, weekday::friday,
weekday::saturday,
};
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;
}
wd += k_weekday_offsets[cd.month()] + cd.day();
return k_weekday_by_sun_off[(wd % 7 + 7) % 7];
}
////////////////////////////////////////////////////////////////////////
CONSTEXPR_F civil_day next_weekday(civil_day cd, weekday wd) noexcept {
do { cd += 1; } while (get_weekday(cd) != wd);
return cd;
}
CONSTEXPR_F civil_day prev_weekday(civil_day cd, weekday wd) noexcept {
do { cd -= 1; } while (get_weekday(cd) != wd);
return cd;
}
CONSTEXPR_F int get_yearday(const civil_day& cd) noexcept {
CONSTEXPR_D int k_month_offsets[1 + 12] = {
-1, 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334,
};
const int feb29 = (cd.month() > 2 && impl::is_leap_year(cd.year()));
return k_month_offsets[cd.month()] + feb29 + cd.day();
}
////////////////////////////////////////////////////////////////////////
std::ostream& operator<<(std::ostream& os, const civil_year& y);
std::ostream& operator<<(std::ostream& os, const civil_month& m);
std::ostream& operator<<(std::ostream& os, const civil_day& d);
std::ostream& operator<<(std::ostream& os, const civil_hour& h);
std::ostream& operator<<(std::ostream& os, const civil_minute& m);
std::ostream& operator<<(std::ostream& os, const civil_second& s);
std::ostream& operator<<(std::ostream& os, weekday wd);
} // namespace detail
} // namespace cctz
} // namespace time_internal
} // namespace absl
#undef CONSTEXPR_M
#undef CONSTEXPR_F
#undef CONSTEXPR_D
#endif // ABSL_TIME_INTERNAL_CCTZ_CIVIL_TIME_DETAIL_H_

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// Copyright 2016 Google Inc. All Rights Reserved.
//
// 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.
// A library for translating between absolute times (represented by
// std::chrono::time_points of the std::chrono::system_clock) and civil
// times (represented by cctz::civil_second) using the rules defined by
// a time zone (cctz::time_zone).
#ifndef ABSL_TIME_INTERNAL_CCTZ_TIME_ZONE_H_
#define ABSL_TIME_INTERNAL_CCTZ_TIME_ZONE_H_
#include <chrono>
#include <cstdint>
#include <string>
#include <utility>
#include "absl/time/internal/cctz/include/cctz/civil_time.h"
namespace absl {
namespace time_internal {
namespace cctz {
// Convenience aliases. Not intended as public API points.
template <typename D>
using time_point = std::chrono::time_point<std::chrono::system_clock, D>;
using sys_seconds = std::chrono::duration<std::int_fast64_t>;
namespace detail {
template <typename D>
inline std::pair<time_point<sys_seconds>, D>
split_seconds(const time_point<D>& tp) {
auto sec = std::chrono::time_point_cast<sys_seconds>(tp);
auto sub = tp - sec;
if (sub.count() < 0) {
sec -= sys_seconds(1);
sub += sys_seconds(1);
}
return {sec, std::chrono::duration_cast<D>(sub)};
}
inline std::pair<time_point<sys_seconds>, sys_seconds>
split_seconds(const time_point<sys_seconds>& tp) {
return {tp, sys_seconds(0)};
}
} // namespace detail
// cctz::time_zone is an opaque, small, value-type class representing a
// geo-political region within which particular rules are used for mapping
// between absolute and civil times. Time zones are named using the TZ
// identifiers from the IANA Time Zone Database, such as "America/Los_Angeles"
// or "Australia/Sydney". Time zones are created from factory functions such
// as load_time_zone(). Note: strings like "PST" and "EDT" are not valid TZ
// identifiers.
//
// Example:
// cctz::time_zone utc = cctz::utc_time_zone();
// cctz::time_zone pst = cctz::fixed_time_zone(std::chrono::hours(-8));
// cctz::time_zone loc = cctz::local_time_zone();
// cctz::time_zone lax;
// if (!cctz::load_time_zone("America/Los_Angeles", &lax)) { ... }
//
// See also:
// - http://www.iana.org/time-zones
// - http://en.wikipedia.org/wiki/Zoneinfo
class time_zone {
public:
time_zone() : time_zone(nullptr) {} // Equivalent to UTC
time_zone(const time_zone&) = default;
time_zone& operator=(const time_zone&) = default;
std::string name() const;
// An absolute_lookup represents the civil time (cctz::civil_second) within
// this time_zone at the given absolute time (time_point). There are
// additionally a few other fields that may be useful when working with
// older APIs, such as std::tm.
//
// Example:
// const cctz::time_zone tz = ...
// const auto tp = std::chrono::system_clock::now();
// const cctz::time_zone::absolute_lookup al = tz.lookup(tp);
struct absolute_lookup {
civil_second cs;
// Note: The following fields exist for backward compatibility with older
// APIs. Accessing these fields directly is a sign of imprudent logic in
// the calling code. Modern time-related code should only access this data
// indirectly by way of cctz::format().
int offset; // civil seconds east of UTC
bool is_dst; // is offset non-standard?
const char* abbr; // time-zone abbreviation (e.g., "PST")
};
absolute_lookup lookup(const time_point<sys_seconds>& tp) const;
template <typename D>
absolute_lookup lookup(const time_point<D>& tp) const {
return lookup(detail::split_seconds(tp).first);
}
// A civil_lookup represents the absolute time(s) (time_point) that
// correspond to the given civil time (cctz::civil_second) within this
// time_zone. Usually the given civil time represents a unique instant
// in time, in which case the conversion is unambiguous. However,
// within this time zone, the given civil time may be skipped (e.g.,
// during a positive UTC offset shift), or repeated (e.g., during a
// negative UTC offset shift). To account for these possibilities,
// civil_lookup is richer than just a single time_point.
//
// In all cases the civil_lookup::kind enum will indicate the nature
// of the given civil-time argument, and the pre, trans, and post
// members will give the absolute time answers using the pre-transition
// offset, the transition point itself, and the post-transition offset,
// respectively (all three times are equal if kind == UNIQUE). If any
// of these three absolute times is outside the representable range of a
// time_point<sys_seconds> the field is set to its maximum/minimum value.
//
// Example:
// cctz::time_zone lax;
// if (!cctz::load_time_zone("America/Los_Angeles", &lax)) { ... }
//
// // A unique civil time.
// auto jan01 = lax.lookup(cctz::civil_second(2011, 1, 1, 0, 0, 0));
// // jan01.kind == cctz::time_zone::civil_lookup::UNIQUE
// // jan01.pre is 2011/01/01 00:00:00 -0800
// // jan01.trans is 2011/01/01 00:00:00 -0800
// // jan01.post is 2011/01/01 00:00:00 -0800
//
// // A Spring DST transition, when there is a gap in civil time.
// auto mar13 = lax.lookup(cctz::civil_second(2011, 3, 13, 2, 15, 0));
// // mar13.kind == cctz::time_zone::civil_lookup::SKIPPED
// // mar13.pre is 2011/03/13 03:15:00 -0700
// // mar13.trans is 2011/03/13 03:00:00 -0700
// // mar13.post is 2011/03/13 01:15:00 -0800
//
// // A Fall DST transition, when civil times are repeated.
// auto nov06 = lax.lookup(cctz::civil_second(2011, 11, 6, 1, 15, 0));
// // nov06.kind == cctz::time_zone::civil_lookup::REPEATED
// // nov06.pre is 2011/11/06 01:15:00 -0700
// // nov06.trans is 2011/11/06 01:00:00 -0800
// // nov06.post is 2011/11/06 01:15:00 -0800
struct civil_lookup {
enum civil_kind {
UNIQUE, // the civil time was singular (pre == trans == post)
SKIPPED, // the civil time did not exist (pre >= trans > post)
REPEATED, // the civil time was ambiguous (pre < trans <= post)
} kind;
time_point<sys_seconds> pre; // uses the pre-transition offset
time_point<sys_seconds> trans; // instant of civil-offset change
time_point<sys_seconds> post; // uses the post-transition offset
};
civil_lookup lookup(const civil_second& cs) const;
class Impl;
private:
explicit time_zone(const Impl* impl) : impl_(impl) {}
const Impl* impl_;
};
// Relational operators.
bool operator==(time_zone lhs, time_zone rhs);
inline bool operator!=(time_zone lhs, time_zone rhs) { return !(lhs == rhs); }
// Loads the named time zone. May perform I/O on the initial load.
// If the name is invalid, or some other kind of error occurs, returns
// false and "*tz" is set to the UTC time zone.
bool load_time_zone(const std::string& name, time_zone* tz);
// Returns a time_zone representing UTC. Cannot fail.
time_zone utc_time_zone();
// Returns a time zone that is a fixed offset (seconds east) from UTC.
// Note: If the absolute value of the offset is greater than 24 hours
// you'll get UTC (i.e., zero offset) instead.
time_zone fixed_time_zone(const sys_seconds& offset);
// Returns a time zone representing the local time zone. Falls back to UTC.
time_zone local_time_zone();
// Returns the civil time (cctz::civil_second) within the given time zone at
// the given absolute time (time_point). Since the additional fields provided
// by the time_zone::absolute_lookup struct should rarely be needed in modern
// code, this convert() function is simpler and should be preferred.
template <typename D>
inline civil_second convert(const time_point<D>& tp, const time_zone& tz) {
return tz.lookup(tp).cs;
}
// Returns the absolute time (time_point) that corresponds to the given civil
// time within the given time zone. If the civil time is not unique (i.e., if
// it was either repeated or non-existent), then the returned time_point is
// the best estimate that preserves relative order. That is, this function
// guarantees that if cs1 < cs2, then convert(cs1, tz) <= convert(cs2, tz).
inline time_point<sys_seconds> convert(const civil_second& cs,
const time_zone& tz) {
const time_zone::civil_lookup cl = tz.lookup(cs);
if (cl.kind == time_zone::civil_lookup::SKIPPED) return cl.trans;
return cl.pre;
}
namespace detail {
using femtoseconds = std::chrono::duration<std::int_fast64_t, std::femto>;
std::string format(const std::string&, const time_point<sys_seconds>&,
const femtoseconds&, const time_zone&);
bool parse(const std::string&, const std::string&, const time_zone&,
time_point<sys_seconds>*, femtoseconds*, std::string* err = nullptr);
} // namespace detail
// Formats the given time_point in the given cctz::time_zone according to
// the provided format std::string. Uses strftime()-like formatting options,
// with the following extensions:
//
// - %Ez - RFC3339-compatible numeric UTC offset (+hh:mm or -hh:mm)
// - %E*z - Full-resolution numeric UTC offset (+hh:mm:ss or -hh:mm:ss)
// - %E#S - Seconds with # digits of fractional precision
// - %E*S - Seconds with full fractional precision (a literal '*')
// - %E#f - Fractional seconds with # digits of precision
// - %E*f - Fractional seconds with full precision (a literal '*')
// - %E4Y - Four-character years (-999 ... -001, 0000, 0001 ... 9999)
//
// Note that %E0S behaves like %S, and %E0f produces no characters. In
// contrast %E*f always produces at least one digit, which may be '0'.
//
// Note that %Y produces as many characters as it takes to fully render the
// year. A year outside of [-999:9999] when formatted with %E4Y will produce
// more than four characters, just like %Y.
//
// Tip: Format strings should include the UTC offset (e.g., %z, %Ez, or %E*z)
// so that the resulting std::string uniquely identifies an absolute time.
//
// Example:
// cctz::time_zone lax;
// if (!cctz::load_time_zone("America/Los_Angeles", &lax)) { ... }
// auto tp = cctz::convert(cctz::civil_second(2013, 1, 2, 3, 4, 5), lax);
// std::string f = cctz::format("%H:%M:%S", tp, lax); // "03:04:05"
// f = cctz::format("%H:%M:%E3S", tp, lax); // "03:04:05.000"
template <typename D>
inline std::string format(const std::string& fmt, const time_point<D>& tp,
const time_zone& tz) {
const auto p = detail::split_seconds(tp);
const auto n = std::chrono::duration_cast<detail::femtoseconds>(p.second);
return detail::format(fmt, p.first, n, tz);
}
// Parses an input std::string according to the provided format std::string and
// returns the corresponding time_point. Uses strftime()-like formatting
// options, with the same extensions as cctz::format(), but with the
// exceptions that %E#S is interpreted as %E*S, and %E#f as %E*f. %Ez
// and %E*z also accept the same inputs.
//
// %Y consumes as many numeric characters as it can, so the matching data
// should always be terminated with a non-numeric. %E4Y always consumes
// exactly four characters, including any sign.
//
// Unspecified fields are taken from the default date and time of ...
//
// "1970-01-01 00:00:00.0 +0000"
//
// For example, parsing a std::string of "15:45" (%H:%M) will return a time_point
// that represents "1970-01-01 15:45:00.0 +0000".
//
// Note that parse() returns time instants, so it makes most sense to parse
// fully-specified date/time strings that include a UTC offset (%z, %Ez, or
// %E*z).
//
// Note also that parse() only heeds the fields year, month, day, hour,
// minute, (fractional) second, and UTC offset. Other fields, like weekday (%a
// or %A), while parsed for syntactic validity, are ignored in the conversion.
//
// Date and time fields that are out-of-range will be treated as errors rather
// than normalizing them like cctz::civil_second() would do. For example, it
// is an error to parse the date "Oct 32, 2013" because 32 is out of range.
//
// A second of ":60" is normalized to ":00" of the following minute with
// fractional seconds discarded. The following table shows how the given
// seconds and subseconds will be parsed:
//
// "59.x" -> 59.x // exact
// "60.x" -> 00.0 // normalized
// "00.x" -> 00.x // exact
//
// Errors are indicated by returning false.
//
// Example:
// const cctz::time_zone tz = ...
// std::chrono::system_clock::time_point tp;
// if (cctz::parse("%Y-%m-%d", "2015-10-09", tz, &tp)) {
// ...
// }
template <typename D>
inline bool parse(const std::string& fmt, const std::string& input,
const time_zone& tz, time_point<D>* tpp) {
time_point<sys_seconds> sec;
detail::femtoseconds fs;
const bool b = detail::parse(fmt, input, tz, &sec, &fs);
if (b) {
// TODO: Return false if unrepresentable as a time_point<D>.
*tpp = std::chrono::time_point_cast<D>(sec);
*tpp += std::chrono::duration_cast<D>(fs);
}
return b;
}
} // namespace cctz
} // namespace time_internal
} // namespace absl
#endif // ABSL_TIME_INTERNAL_CCTZ_TIME_ZONE_H_

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// Copyright 2016 Google Inc. All Rights Reserved.
//
// 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.
#ifndef ABSL_TIME_INTERNAL_CCTZ_ZONE_INFO_SOURCE_H_
#define ABSL_TIME_INTERNAL_CCTZ_ZONE_INFO_SOURCE_H_
#include <cstddef>
#include <functional>
#include <memory>
#include <string>
namespace absl {
namespace time_internal {
namespace cctz {
// A stdio-like interface for providing zoneinfo data for a particular zone.
class ZoneInfoSource {
public:
virtual ~ZoneInfoSource();
virtual std::size_t Read(void* ptr, std::size_t size) = 0; // like fread()
virtual int Skip(std::size_t offset) = 0; // like fseek()
};
} // namespace cctz
} // namespace time_internal
} // namespace absl
namespace absl {
namespace time_internal {
namespace cctz_extension {
// A function-pointer type for a factory that returns a ZoneInfoSource
// given the name of a time zone and a fallback factory. Returns null
// when the data for the named zone cannot be found.
using ZoneInfoSourceFactory =
std::unique_ptr<absl::time_internal::cctz::ZoneInfoSource> (*)(
const std::string&,
const std::function<std::unique_ptr<absl::time_internal::cctz::ZoneInfoSource>(
const std::string&)>&);
// The user can control the mapping of zone names to zoneinfo data by
// providing a definition for cctz_extension::zone_info_source_factory.
// For example, given functions my_factory() and my_other_factory() that
// can return a ZoneInfoSource for a named zone, we could inject them into
// cctz::load_time_zone() with:
//
// namespace cctz_extension {
// namespace {
// std::unique_ptr<cctz::ZoneInfoSource> CustomFactory(
// const std::string& name,
// const std::function<std::unique_ptr<cctz::ZoneInfoSource>(
// const std::string& name)>& fallback_factory) {
// if (auto zip = my_factory(name)) return zip;
// if (auto zip = fallback_factory(name)) return zip;
// if (auto zip = my_other_factory(name)) return zip;
// return nullptr;
// }
// } // namespace
// ZoneInfoSourceFactory zone_info_source_factory = CustomFactory;
// } // namespace cctz_extension
//
// This might be used, say, to use zoneinfo data embedded in the program,
// or read from a (possibly compressed) file archive, or both.
//
// cctz_extension::zone_info_source_factory() will be called:
// (1) from the same thread as the cctz::load_time_zone() call,
// (2) only once for any zone name, and
// (3) serially (i.e., no concurrent execution).
//
// The fallback factory obtains zoneinfo data by reading files in ${TZDIR},
// and it is used automatically when no zone_info_source_factory definition
// is linked into the program.
extern ZoneInfoSourceFactory zone_info_source_factory;
} // namespace cctz_extension
} // namespace time_internal
} // namespace absl
#endif // ABSL_TIME_INTERNAL_CCTZ_ZONE_INFO_SOURCE_H_