// 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.

#include <algorithm>
#include <cassert>
#include <chrono>
#include <ctime>
#include <random>
#include <string>
#include <vector>

#include "benchmark/benchmark.h"
#include "absl/time/internal/cctz/include/cctz/civil_time.h"
#include "absl/time/internal/cctz/include/cctz/time_zone.h"
#include "time_zone_impl.h"

namespace {

namespace cctz = absl::time_internal::cctz;

void BM_Difference_Days(benchmark::State& state) {
  const cctz::civil_day c(2014, 8, 22);
  const cctz::civil_day epoch(1970, 1, 1);
  while (state.KeepRunning()) {
    benchmark::DoNotOptimize(c - epoch);
  }
}
BENCHMARK(BM_Difference_Days);

void BM_Step_Days(benchmark::State& state) {
  const cctz::civil_day kStart(2014, 8, 22);
  cctz::civil_day c = kStart;
  while (state.KeepRunning()) {
    benchmark::DoNotOptimize(++c);
  }
}
BENCHMARK(BM_Step_Days);

const char RFC3339_full[] = "%Y-%m-%dT%H:%M:%E*S%Ez";
const char RFC3339_sec[] = "%Y-%m-%dT%H:%M:%S%Ez";

const char RFC1123_full[] = "%a, %d %b %Y %H:%M:%S %z";
const char RFC1123_no_wday[] = "%d %b %Y %H:%M:%S %z";

// A list of known time-zone names.
// TODO: Refactor with src/time_zone_lookup_test.cc.
const char* const kTimeZoneNames[] = {
  "Africa/Abidjan",
  "Africa/Accra",
  "Africa/Addis_Ababa",
  "Africa/Algiers",
  "Africa/Asmara",
  "Africa/Asmera",
  "Africa/Bamako",
  "Africa/Bangui",
  "Africa/Banjul",
  "Africa/Bissau",
  "Africa/Blantyre",
  "Africa/Brazzaville",
  "Africa/Bujumbura",
  "Africa/Cairo",
  "Africa/Casablanca",
  "Africa/Ceuta",
  "Africa/Conakry",
  "Africa/Dakar",
  "Africa/Dar_es_Salaam",
  "Africa/Djibouti",
  "Africa/Douala",
  "Africa/El_Aaiun",
  "Africa/Freetown",
  "Africa/Gaborone",
  "Africa/Harare",
  "Africa/Johannesburg",
  "Africa/Juba",
  "Africa/Kampala",
  "Africa/Khartoum",
  "Africa/Kigali",
  "Africa/Kinshasa",
  "Africa/Lagos",
  "Africa/Libreville",
  "Africa/Lome",
  "Africa/Luanda",
  "Africa/Lubumbashi",
  "Africa/Lusaka",
  "Africa/Malabo",
  "Africa/Maputo",
  "Africa/Maseru",
  "Africa/Mbabane",
  "Africa/Mogadishu",
  "Africa/Monrovia",
  "Africa/Nairobi",
  "Africa/Ndjamena",
  "Africa/Niamey",
  "Africa/Nouakchott",
  "Africa/Ouagadougou",
  "Africa/Porto-Novo",
  "Africa/Sao_Tome",
  "Africa/Timbuktu",
  "Africa/Tripoli",
  "Africa/Tunis",
  "Africa/Windhoek",
  "America/Adak",
  "America/Anchorage",
  "America/Anguilla",
  "America/Antigua",
  "America/Araguaina",
  "America/Argentina/Buenos_Aires",
  "America/Argentina/Catamarca",
  "America/Argentina/ComodRivadavia",
  "America/Argentina/Cordoba",
  "America/Argentina/Jujuy",
  "America/Argentina/La_Rioja",
  "America/Argentina/Mendoza",
  "America/Argentina/Rio_Gallegos",
  "America/Argentina/Salta",
  "America/Argentina/San_Juan",
  "America/Argentina/San_Luis",
  "America/Argentina/Tucuman",
  "America/Argentina/Ushuaia",
  "America/Aruba",
  "America/Asuncion",
  "America/Atikokan",
  "America/Atka",
  "America/Bahia",
  "America/Bahia_Banderas",
  "America/Barbados",
  "America/Belem",
  "America/Belize",
  "America/Blanc-Sablon",
  "America/Boa_Vista",
  "America/Bogota",
  "America/Boise",
  "America/Buenos_Aires",
  "America/Cambridge_Bay",
  "America/Campo_Grande",
  "America/Cancun",
  "America/Caracas",
  "America/Catamarca",
  "America/Cayenne",
  "America/Cayman",
  "America/Chicago",
  "America/Chihuahua",
  "America/Coral_Harbour",
  "America/Cordoba",
  "America/Costa_Rica",
  "America/Creston",
  "America/Cuiaba",
  "America/Curacao",
  "America/Danmarkshavn",
  "America/Dawson",
  "America/Dawson_Creek",
  "America/Denver",
  "America/Detroit",
  "America/Dominica",
  "America/Edmonton",
  "America/Eirunepe",
  "America/El_Salvador",
  "America/Ensenada",
  "America/Fort_Nelson",
  "America/Fort_Wayne",
  "America/Fortaleza",
  "America/Glace_Bay",
  "America/Godthab",
  "America/Goose_Bay",
  "America/Grand_Turk",
  "America/Grenada",
  "America/Guadeloupe",
  "America/Guatemala",
  "America/Guayaquil",
  "America/Guyana",
  "America/Halifax",
  "America/Havana",
  "America/Hermosillo",
  "America/Indiana/Indianapolis",
  "America/Indiana/Knox",
  "America/Indiana/Marengo",
  "America/Indiana/Petersburg",
  "America/Indiana/Tell_City",
  "America/Indiana/Vevay",
  "America/Indiana/Vincennes",
  "America/Indiana/Winamac",
  "America/Indianapolis",
  "America/Inuvik",
  "America/Iqaluit",
  "America/Jamaica",
  "America/Jujuy",
  "America/Juneau",
  "America/Kentucky/Louisville",
  "America/Kentucky/Monticello",
  "America/Knox_IN",
  "America/Kralendijk",
  "America/La_Paz",
  "America/Lima",
  "America/Los_Angeles",
  "America/Louisville",
  "America/Lower_Princes",
  "America/Maceio",
  "America/Managua",
  "America/Manaus",
  "America/Marigot",
  "America/Martinique",
  "America/Matamoros",
  "America/Mazatlan",
  "America/Mendoza",
  "America/Menominee",
  "America/Merida",
  "America/Metlakatla",
  "America/Mexico_City",
  "America/Miquelon",
  "America/Moncton",
  "America/Monterrey",
  "America/Montevideo",
  "America/Montreal",
  "America/Montserrat",
  "America/Nassau",
  "America/New_York",
  "America/Nipigon",
  "America/Nome",
  "America/Noronha",
  "America/North_Dakota/Beulah",
  "America/North_Dakota/Center",
  "America/North_Dakota/New_Salem",
  "America/Ojinaga",
  "America/Panama",
  "America/Pangnirtung",
  "America/Paramaribo",
  "America/Phoenix",
  "America/Port-au-Prince",
  "America/Port_of_Spain",
  "America/Porto_Acre",
  "America/Porto_Velho",
  "America/Puerto_Rico",
  "America/Punta_Arenas",
  "America/Rainy_River",
  "America/Rankin_Inlet",
  "America/Recife",
  "America/Regina",
  "America/Resolute",
  "America/Rio_Branco",
  "America/Rosario",
  "America/Santa_Isabel",
  "America/Santarem",
  "America/Santiago",
  "America/Santo_Domingo",
  "America/Sao_Paulo",
  "America/Scoresbysund",
  "America/Shiprock",
  "America/Sitka",
  "America/St_Barthelemy",
  "America/St_Johns",
  "America/St_Kitts",
  "America/St_Lucia",
  "America/St_Thomas",
  "America/St_Vincent",
  "America/Swift_Current",
  "America/Tegucigalpa",
  "America/Thule",
  "America/Thunder_Bay",
  "America/Tijuana",
  "America/Toronto",
  "America/Tortola",
  "America/Vancouver",
  "America/Virgin",
  "America/Whitehorse",
  "America/Winnipeg",
  "America/Yakutat",
  "America/Yellowknife",
  "Antarctica/Casey",
  "Antarctica/Davis",
  "Antarctica/DumontDUrville",
  "Antarctica/Macquarie",
  "Antarctica/Mawson",
  "Antarctica/McMurdo",
  "Antarctica/Palmer",
  "Antarctica/Rothera",
  "Antarctica/South_Pole",
  "Antarctica/Syowa",
  "Antarctica/Troll",
  "Antarctica/Vostok",
  "Arctic/Longyearbyen",
  "Asia/Aden",
  "Asia/Almaty",
  "Asia/Amman",
  "Asia/Anadyr",
  "Asia/Aqtau",
  "Asia/Aqtobe",
  "Asia/Ashgabat",
  "Asia/Ashkhabad",
  "Asia/Atyrau",
  "Asia/Baghdad",
  "Asia/Bahrain",
  "Asia/Baku",
  "Asia/Bangkok",
  "Asia/Barnaul",
  "Asia/Beirut",
  "Asia/Bishkek",
  "Asia/Brunei",
  "Asia/Calcutta",
  "Asia/Chita",
  "Asia/Choibalsan",
  "Asia/Chongqing",
  "Asia/Chungking",
  "Asia/Colombo",
  "Asia/Dacca",
  "Asia/Damascus",
  "Asia/Dhaka",
  "Asia/Dili",
  "Asia/Dubai",
  "Asia/Dushanbe",
  "Asia/Famagusta",
  "Asia/Gaza",
  "Asia/Harbin",
  "Asia/Hebron",
  "Asia/Ho_Chi_Minh",
  "Asia/Hong_Kong",
  "Asia/Hovd",
  "Asia/Irkutsk",
  "Asia/Istanbul",
  "Asia/Jakarta",
  "Asia/Jayapura",
  "Asia/Jerusalem",
  "Asia/Kabul",
  "Asia/Kamchatka",
  "Asia/Karachi",
  "Asia/Kashgar",
  "Asia/Kathmandu",
  "Asia/Katmandu",
  "Asia/Khandyga",
  "Asia/Kolkata",
  "Asia/Krasnoyarsk",
  "Asia/Kuala_Lumpur",
  "Asia/Kuching",
  "Asia/Kuwait",
  "Asia/Macao",
  "Asia/Macau",
  "Asia/Magadan",
  "Asia/Makassar",
  "Asia/Manila",
  "Asia/Muscat",
  "Asia/Nicosia",
  "Asia/Novokuznetsk",
  "Asia/Novosibirsk",
  "Asia/Omsk",
  "Asia/Oral",
  "Asia/Phnom_Penh",
  "Asia/Pontianak",
  "Asia/Pyongyang",
  "Asia/Qatar",
  "Asia/Qyzylorda",
  "Asia/Rangoon",
  "Asia/Riyadh",
  "Asia/Saigon",
  "Asia/Sakhalin",
  "Asia/Samarkand",
  "Asia/Seoul",
  "Asia/Shanghai",
  "Asia/Singapore",
  "Asia/Srednekolymsk",
  "Asia/Taipei",
  "Asia/Tashkent",
  "Asia/Tbilisi",
  "Asia/Tehran",
  "Asia/Tel_Aviv",
  "Asia/Thimbu",
  "Asia/Thimphu",
  "Asia/Tokyo",
  "Asia/Tomsk",
  "Asia/Ujung_Pandang",
  "Asia/Ulaanbaatar",
  "Asia/Ulan_Bator",
  "Asia/Urumqi",
  "Asia/Ust-Nera",
  "Asia/Vientiane",
  "Asia/Vladivostok",
  "Asia/Yakutsk",
  "Asia/Yangon",
  "Asia/Yekaterinburg",
  "Asia/Yerevan",
  "Atlantic/Azores",
  "Atlantic/Bermuda",
  "Atlantic/Canary",
  "Atlantic/Cape_Verde",
  "Atlantic/Faeroe",
  "Atlantic/Faroe",
  "Atlantic/Jan_Mayen",
  "Atlantic/Madeira",
  "Atlantic/Reykjavik",
  "Atlantic/South_Georgia",
  "Atlantic/St_Helena",
  "Atlantic/Stanley",
  "Australia/ACT",
  "Australia/Adelaide",
  "Australia/Brisbane",
  "Australia/Broken_Hill",
  "Australia/Canberra",
  "Australia/Currie",
  "Australia/Darwin",
  "Australia/Eucla",
  "Australia/Hobart",
  "Australia/LHI",
  "Australia/Lindeman",
  "Australia/Lord_Howe",
  "Australia/Melbourne",
  "Australia/NSW",
  "Australia/North",
  "Australia/Perth",
  "Australia/Queensland",
  "Australia/South",
  "Australia/Sydney",
  "Australia/Tasmania",
  "Australia/Victoria",
  "Australia/West",
  "Australia/Yancowinna",
  "Brazil/Acre",
  "Brazil/DeNoronha",
  "Brazil/East",
  "Brazil/West",
  "CET",
  "CST6CDT",
  "Canada/Atlantic",
  "Canada/Central",
  "Canada/Eastern",
  "Canada/Mountain",
  "Canada/Newfoundland",
  "Canada/Pacific",
  "Canada/Saskatchewan",
  "Canada/Yukon",
  "Chile/Continental",
  "Chile/EasterIsland",
  "Cuba",
  "EET",
  "EST",
  "EST5EDT",
  "Egypt",
  "Eire",
  "Etc/GMT",
  "Etc/GMT+0",
  "Etc/GMT+1",
  "Etc/GMT+10",
  "Etc/GMT+11",
  "Etc/GMT+12",
  "Etc/GMT+2",
  "Etc/GMT+3",
  "Etc/GMT+4",
  "Etc/GMT+5",
  "Etc/GMT+6",
  "Etc/GMT+7",
  "Etc/GMT+8",
  "Etc/GMT+9",
  "Etc/GMT-0",
  "Etc/GMT-1",
  "Etc/GMT-10",
  "Etc/GMT-11",
  "Etc/GMT-12",
  "Etc/GMT-13",
  "Etc/GMT-14",
  "Etc/GMT-2",
  "Etc/GMT-3",
  "Etc/GMT-4",
  "Etc/GMT-5",
  "Etc/GMT-6",
  "Etc/GMT-7",
  "Etc/GMT-8",
  "Etc/GMT-9",
  "Etc/GMT0",
  "Etc/Greenwich",
  "Etc/UCT",
  "Etc/UTC",
  "Etc/Universal",
  "Etc/Zulu",
  "Europe/Amsterdam",
  "Europe/Andorra",
  "Europe/Astrakhan",
  "Europe/Athens",
  "Europe/Belfast",
  "Europe/Belgrade",
  "Europe/Berlin",
  "Europe/Bratislava",
  "Europe/Brussels",
  "Europe/Bucharest",
  "Europe/Budapest",
  "Europe/Busingen",
  "Europe/Chisinau",
  "Europe/Copenhagen",
  "Europe/Dublin",
  "Europe/Gibraltar",
  "Europe/Guernsey",
  "Europe/Helsinki",
  "Europe/Isle_of_Man",
  "Europe/Istanbul",
  "Europe/Jersey",
  "Europe/Kaliningrad",
  "Europe/Kiev",
  "Europe/Kirov",
  "Europe/Lisbon",
  "Europe/Ljubljana",
  "Europe/London",
  "Europe/Luxembourg",
  "Europe/Madrid",
  "Europe/Malta",
  "Europe/Mariehamn",
  "Europe/Minsk",
  "Europe/Monaco",
  "Europe/Moscow",
  "Europe/Nicosia",
  "Europe/Oslo",
  "Europe/Paris",
  "Europe/Podgorica",
  "Europe/Prague",
  "Europe/Riga",
  "Europe/Rome",
  "Europe/Samara",
  "Europe/San_Marino",
  "Europe/Sarajevo",
  "Europe/Saratov",
  "Europe/Simferopol",
  "Europe/Skopje",
  "Europe/Sofia",
  "Europe/Stockholm",
  "Europe/Tallinn",
  "Europe/Tirane",
  "Europe/Tiraspol",
  "Europe/Ulyanovsk",
  "Europe/Uzhgorod",
  "Europe/Vaduz",
  "Europe/Vatican",
  "Europe/Vienna",
  "Europe/Vilnius",
  "Europe/Volgograd",
  "Europe/Warsaw",
  "Europe/Zagreb",
  "Europe/Zaporozhye",
  "Europe/Zurich",
  "GB",
  "GB-Eire",
  "GMT",
  "GMT+0",
  "GMT-0",
  "GMT0",
  "Greenwich",
  "HST",
  "Hongkong",
  "Iceland",
  "Indian/Antananarivo",
  "Indian/Chagos",
  "Indian/Christmas",
  "Indian/Cocos",
  "Indian/Comoro",
  "Indian/Kerguelen",
  "Indian/Mahe",
  "Indian/Maldives",
  "Indian/Mauritius",
  "Indian/Mayotte",
  "Indian/Reunion",
  "Iran",
  "Israel",
  "Jamaica",
  "Japan",
  "Kwajalein",
  "Libya",
  "MET",
  "MST",
  "MST7MDT",
  "Mexico/BajaNorte",
  "Mexico/BajaSur",
  "Mexico/General",
  "NZ",
  "NZ-CHAT",
  "Navajo",
  "PRC",
  "PST8PDT",
  "Pacific/Apia",
  "Pacific/Auckland",
  "Pacific/Bougainville",
  "Pacific/Chatham",
  "Pacific/Chuuk",
  "Pacific/Easter",
  "Pacific/Efate",
  "Pacific/Enderbury",
  "Pacific/Fakaofo",
  "Pacific/Fiji",
  "Pacific/Funafuti",
  "Pacific/Galapagos",
  "Pacific/Gambier",
  "Pacific/Guadalcanal",
  "Pacific/Guam",
  "Pacific/Honolulu",
  "Pacific/Johnston",
  "Pacific/Kiritimati",
  "Pacific/Kosrae",
  "Pacific/Kwajalein",
  "Pacific/Majuro",
  "Pacific/Marquesas",
  "Pacific/Midway",
  "Pacific/Nauru",
  "Pacific/Niue",
  "Pacific/Norfolk",
  "Pacific/Noumea",
  "Pacific/Pago_Pago",
  "Pacific/Palau",
  "Pacific/Pitcairn",
  "Pacific/Pohnpei",
  "Pacific/Ponape",
  "Pacific/Port_Moresby",
  "Pacific/Rarotonga",
  "Pacific/Saipan",
  "Pacific/Samoa",
  "Pacific/Tahiti",
  "Pacific/Tarawa",
  "Pacific/Tongatapu",
  "Pacific/Truk",
  "Pacific/Wake",
  "Pacific/Wallis",
  "Pacific/Yap",
  "Poland",
  "Portugal",
  "ROC",
  "ROK",
  "Singapore",
  "Turkey",
  "UCT",
  "US/Alaska",
  "US/Aleutian",
  "US/Arizona",
  "US/Central",
  "US/East-Indiana",
  "US/Eastern",
  "US/Hawaii",
  "US/Indiana-Starke",
  "US/Michigan",
  "US/Mountain",
  "US/Pacific",
  "US/Samoa",
  "UTC",
  "Universal",
  "W-SU",
  "WET",
  "Zulu",
  nullptr
};

std::vector<std::string> AllTimeZoneNames() {
  std::vector<std::string> names;
  for (const char* const* namep = kTimeZoneNames; *namep != nullptr; ++namep) {
    names.push_back(std::string("file:") + *namep);
  }
  assert(!names.empty());

  std::mt19937 urbg(42);  // a UniformRandomBitGenerator with fixed seed
  std::shuffle(names.begin(), names.end(), urbg);
  return names;
}

cctz::time_zone TestTimeZone() {
  cctz::time_zone tz;
  cctz::load_time_zone("America/Los_Angeles", &tz);
  return tz;
}

void BM_Zone_LoadUTCTimeZoneFirst(benchmark::State& state) {
  cctz::time_zone tz;
  cctz::load_time_zone("UTC", &tz);  // in case we're first
  cctz::time_zone::Impl::ClearTimeZoneMapTestOnly();
  while (state.KeepRunning()) {
    benchmark::DoNotOptimize(cctz::load_time_zone("UTC", &tz));
  }
}
BENCHMARK(BM_Zone_LoadUTCTimeZoneFirst);

void BM_Zone_LoadUTCTimeZoneLast(benchmark::State& state) {
  cctz::time_zone tz;
  for (const auto& name : AllTimeZoneNames()) {
    cctz::load_time_zone(name, &tz);  // prime cache
  }
  while (state.KeepRunning()) {
    benchmark::DoNotOptimize(cctz::load_time_zone("UTC", &tz));
  }
}
BENCHMARK(BM_Zone_LoadUTCTimeZoneLast);

void BM_Zone_LoadTimeZoneFirst(benchmark::State& state) {
  cctz::time_zone tz = cctz::utc_time_zone();  // in case we're first
  const std::string name = "file:America/Los_Angeles";
  while (state.KeepRunning()) {
    state.PauseTiming();
    cctz::time_zone::Impl::ClearTimeZoneMapTestOnly();
    state.ResumeTiming();
    benchmark::DoNotOptimize(cctz::load_time_zone(name, &tz));
  }
}
BENCHMARK(BM_Zone_LoadTimeZoneFirst);

void BM_Zone_LoadTimeZoneCached(benchmark::State& state) {
  cctz::time_zone tz = cctz::utc_time_zone();  // in case we're first
  cctz::time_zone::Impl::ClearTimeZoneMapTestOnly();
  const std::string name = "file:America/Los_Angeles";
  cctz::load_time_zone(name, &tz);  // prime cache
  while (state.KeepRunning()) {
    benchmark::DoNotOptimize(cctz::load_time_zone(name, &tz));
  }
}
BENCHMARK(BM_Zone_LoadTimeZoneCached);

void BM_Zone_LoadLocalTimeZoneCached(benchmark::State& state) {
  cctz::utc_time_zone();  // in case we're first
  cctz::time_zone::Impl::ClearTimeZoneMapTestOnly();
  cctz::local_time_zone();  // prime cache
  while (state.KeepRunning()) {
    benchmark::DoNotOptimize(cctz::local_time_zone());
  }
}
BENCHMARK(BM_Zone_LoadLocalTimeZoneCached);

void BM_Zone_LoadAllTimeZonesFirst(benchmark::State& state) {
  cctz::time_zone tz;
  const std::vector<std::string> names = AllTimeZoneNames();
  for (auto index = names.size(); state.KeepRunning(); ++index) {
    if (index == names.size()) {
      index = 0;
    }
    if (index == 0) {
      state.PauseTiming();
      cctz::time_zone::Impl::ClearTimeZoneMapTestOnly();
      state.ResumeTiming();
    }
    benchmark::DoNotOptimize(cctz::load_time_zone(names[index], &tz));
  }
}
BENCHMARK(BM_Zone_LoadAllTimeZonesFirst);

void BM_Zone_LoadAllTimeZonesCached(benchmark::State& state) {
  cctz::time_zone tz;
  const std::vector<std::string> names = AllTimeZoneNames();
  for (const auto& name : names) {
    cctz::load_time_zone(name, &tz);  // prime cache
  }
  for (auto index = names.size(); state.KeepRunning(); ++index) {
    if (index == names.size()) {
      index = 0;
    }
    benchmark::DoNotOptimize(cctz::load_time_zone(names[index], &tz));
  }
}
BENCHMARK(BM_Zone_LoadAllTimeZonesCached);

void BM_Zone_TimeZoneImplGetImplicit(benchmark::State& state) {
  cctz::time_zone tz;  // implicit UTC
  cctz::time_zone::Impl::get(tz);
  while (state.KeepRunning()) {
    cctz::time_zone::Impl::get(tz);
  }
}
BENCHMARK(BM_Zone_TimeZoneImplGetImplicit);

void BM_Zone_TimeZoneImplGetExplicit(benchmark::State& state) {
  cctz::time_zone tz = cctz::utc_time_zone();  // explicit UTC
  cctz::time_zone::Impl::get(tz);
  while (state.KeepRunning()) {
    cctz::time_zone::Impl::get(tz);
  }
}
BENCHMARK(BM_Zone_TimeZoneImplGetExplicit);

void BM_Zone_UTCTimeZone(benchmark::State& state) {
  cctz::time_zone tz;
  while (state.KeepRunning()) {
    benchmark::DoNotOptimize(cctz::utc_time_zone());
  }
}
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_).
//
// The "UTC" variants use UTC instead of the Google/local time zone.

void BM_Time_ToDateTime_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);
  std::chrono::system_clock::time_point tp2 =
      std::chrono::system_clock::from_time_t(1418962578);
  while (state.KeepRunning()) {
    std::swap(tp, tp2);
    tp += std::chrono::seconds(1);
    benchmark::DoNotOptimize(cctz::convert(tp, tz));
  }
}
BENCHMARK(BM_Time_ToDateTime_CCTZ);

void BM_Time_ToDateTime_Libc(benchmark::State& state) {
  // No timezone support, so just use localtime.
  time_t t = 1384569027;
  time_t t2 = 1418962578;
  struct tm tm;
  while (state.KeepRunning()) {
    std::swap(t, t2);
    t += 1;
#if defined(_WIN32) || defined(_WIN64)
    benchmark::DoNotOptimize(localtime_s(&tm, &t));
#else
    benchmark::DoNotOptimize(localtime_r(&t, &tm));
#endif
  }
}
BENCHMARK(BM_Time_ToDateTime_Libc);

void BM_Time_ToDateTimeUTC_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);
  while (state.KeepRunning()) {
    tp += std::chrono::seconds(1);
    benchmark::DoNotOptimize(cctz::convert(tp, tz));
  }
}
BENCHMARK(BM_Time_ToDateTimeUTC_CCTZ);

void BM_Time_ToDateTimeUTC_Libc(benchmark::State& state) {
  time_t t = 1384569027;
  struct tm tm;
  while (state.KeepRunning()) {
    t += 1;
#if defined(_WIN32) || defined(_WIN64)
    benchmark::DoNotOptimize(gmtime_s(&tm, &t));
#else
    benchmark::DoNotOptimize(gmtime_r(&t, &tm));
#endif
  }
}
BENCHMARK(BM_Time_ToDateTimeUTC_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_).
//
// 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) {
  const cctz::time_zone tz = TestTimeZone();
  int i = 0;
  while (state.KeepRunning()) {
    if ((i++ & 1) == 0) {
      benchmark::DoNotOptimize(
          cctz::convert(cctz::civil_second(2014, 12, 18, 20, 16, 18), tz));
    } else {
      benchmark::DoNotOptimize(
          cctz::convert(cctz::civil_second(2013, 11, 15, 18, 30, 27), tz));
    }
  }
}
BENCHMARK(BM_Time_FromDateTime_CCTZ);

void BM_Time_FromDateTime_Libc(benchmark::State& state) {
  // No timezone support, so just use localtime.
  int i = 0;
  while (state.KeepRunning()) {
    struct tm tm;
    if ((i++ & 1) == 0) {
      tm.tm_year = 2014 - 1900;
      tm.tm_mon = 12 - 1;
      tm.tm_mday = 18;
      tm.tm_hour = 20;
      tm.tm_min = 16;
      tm.tm_sec = 18;
    } else {
      tm.tm_year = 2013 - 1900;
      tm.tm_mon = 11 - 1;
      tm.tm_mday = 15;
      tm.tm_hour = 18;
      tm.tm_min = 30;
      tm.tm_sec = 27;
    }
    tm.tm_isdst = -1;
    benchmark::DoNotOptimize(mktime(&tm));
  }
}
BENCHMARK(BM_Time_FromDateTime_Libc);

void BM_Time_FromDateTimeUTC_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);

// There is no BM_Time_FromDateTimeUTC_Libc.

void BM_Time_FromDateTimeDay0_CCTZ(benchmark::State& state) {
  const cctz::time_zone tz = TestTimeZone();
  int i = 0;
  while (state.KeepRunning()) {
    if ((i++ & 1) == 0) {
      benchmark::DoNotOptimize(
          cctz::convert(cctz::civil_second(2014, 12, 0, 20, 16, 18), tz));
    } else {
      benchmark::DoNotOptimize(
          cctz::convert(cctz::civil_second(2013, 11, 0, 18, 30, 27), tz));
    }
  }
}
BENCHMARK(BM_Time_FromDateTimeDay0_CCTZ);

void BM_Time_FromDateTimeDay0_Libc(benchmark::State& state) {
  // No timezone support, so just use localtime.
  int i = 0;
  while (state.KeepRunning()) {
    struct tm tm;
    if ((i++ & 1) == 0) {
      tm.tm_year = 2014 - 1900;
      tm.tm_mon = 12 - 1;
      tm.tm_mday = 0;
      tm.tm_hour = 20;
      tm.tm_min = 16;
      tm.tm_sec = 18;
    } else {
      tm.tm_year = 2013 - 1900;
      tm.tm_mon = 11 - 1;
      tm.tm_mday = 0;
      tm.tm_hour = 18;
      tm.tm_min = 30;
      tm.tm_sec = 27;
    }
    tm.tm_isdst = -1;
    benchmark::DoNotOptimize(mktime(&tm));
  }
}
BENCHMARK(BM_Time_FromDateTimeDay0_Libc);

const char* const kFormats[] = {
    RFC1123_full,         // 0
    RFC1123_no_wday,      // 1
    RFC3339_full,         // 2
    RFC3339_sec,          // 3
    "%Y-%m-%dT%H:%M:%S",  // 4
    "%Y-%m-%d",           // 5
};
const int kNumFormats = sizeof(kFormats) / sizeof(kFormats[0]);

void BM_Format_FormatTime(benchmark::State& state) {
  const std::string fmt = kFormats[state.range(0)];
  state.SetLabel(fmt);
  const cctz::time_zone tz = TestTimeZone();
  const std::chrono::system_clock::time_point tp =
      cctz::convert(cctz::civil_second(1977, 6, 28, 9, 8, 7), tz) +
      std::chrono::microseconds(1);
  while (state.KeepRunning()) {
    benchmark::DoNotOptimize(cctz::format(fmt, tp, tz));
  }
}
BENCHMARK(BM_Format_FormatTime)->DenseRange(0, kNumFormats - 1);

void BM_Format_ParseTime(benchmark::State& state) {
  const std::string fmt = kFormats[state.range(0)];
  state.SetLabel(fmt);
  const cctz::time_zone tz = TestTimeZone();
  std::chrono::system_clock::time_point tp =
      cctz::convert(cctz::civil_second(1977, 6, 28, 9, 8, 7), tz) +
      std::chrono::microseconds(1);
  const std::string when = cctz::format(fmt, tp, tz);
  while (state.KeepRunning()) {
    benchmark::DoNotOptimize(cctz::parse(fmt, when, tz, &tp));
  }
}
BENCHMARK(BM_Format_ParseTime)->DenseRange(0, kNumFormats - 1);

}  // namespace
