ClickHouse/libs/libcommon/include/common/DateLUTImpl.h

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#pragma once
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#include <common/Types.h>
#include <ext/singleton.h>
#include <common/likely.h>
#include <common/strong_typedef.h>
#include <iostream>
#include <vector>
#include <unordered_map>
#include <ctime>
#define DATE_LUT_MIN 0
#define DATE_LUT_MAX (0x7FFFFFFF - 86400)
#define DATE_LUT_MAX_DAY_NUM (0x7FFFFFFF / 86400)
#define DATE_LUT_MIN_YEAR 1970
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#define DATE_LUT_MAX_YEAR 2037 /// Last supported year
#define DATE_LUT_YEARS 68 /// Number of years in lookup table
STRONG_TYPEDEF(UInt16, DayNum_t);
/** Lookup table to conversion of time to date, and to month / year / day of week / day of month and so on.
* First time was implemented for OLAPServer, that needed to do billions of such transformations.
*/
class DateLUTImpl
{
public:
DateLUTImpl(const std::string & time_zone);
public:
struct Values
{
/// Least significat 32 bits from time_t at beginning of the day.
/// Signedness is important to support 1970-01-01 MSK, where time_t == -10800.
/// Change to time_t; change constants above; and recompile the sources if you need to support time after 2038 year.
Int32 date;
/// Properties of the day.
UInt16 year;
UInt8 month;
UInt8 day_of_month;
UInt8 day_of_week;
/// For days, when offset from UTC was changed due to daylight saving time or permanent change, following values could be non zero.
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UInt16 time_at_offset_change; /// In seconds from beginning of the day. Assuming offset never changed close to the end of day (so, value < 65536).
Int16 amount_of_offset_change; /// Usually -3600 or 3600, but look at Lord Howe Island.
};
private:
/// Lookup table is indexed by DayNum.
/// Day nums are the same in all time zones. 1970-01-01 is 0 and so on.
/// Table is relatively large (~30 000 elements), so better not to place object on stack.
/// In comparison to std::vector, plain array is cheaper by one indirection.
Values lut[DATE_LUT_MAX_DAY_NUM + 1];
/// Year number after DATE_LUT_MIN_YEAR -> day num for start of year.
DayNum_t years_lut[DATE_LUT_YEARS];
/// UTC offset at beginning of the Unix epoch.
time_t offset_at_start_of_epoch;
/// Time zone name.
std::string time_zone;
inline size_t findIndex(time_t t) const
{
/// First guess.
size_t guess = t / 86400;
if (guess >= DATE_LUT_MAX_DAY_NUM)
return 0;
if (t >= lut[guess].date && t < lut[guess + 1].date)
return guess;
for (size_t i = 1;; ++i)
{
if (guess + i >= DATE_LUT_MAX_DAY_NUM)
return 0;
if (t >= lut[guess + i].date && t < lut[guess + i + 1].date)
return guess + i;
if (guess < i)
return 0;
if (t >= lut[guess - i].date && t < lut[guess - i + 1].date)
return guess - i;
}
}
inline const Values & find(time_t t) const
{
return lut[findIndex(t)];
}
static inline DayNum_t fixDay(DayNum_t day)
{
return day > DATE_LUT_MAX_DAY_NUM ? static_cast<DayNum_t>(0) : day;
}
public:
const std::string & getTimeZone() const { return time_zone; }
/// всё ниже thread-safe; корректность входных данных не проверяется
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inline time_t toDate(time_t t) const { return find(t).date; }
inline unsigned toMonth(time_t t) const { return find(t).month; }
inline unsigned toYear(time_t t) const { return find(t).year; }
inline unsigned toDayOfWeek(time_t t) const { return find(t).day_of_week; }
inline unsigned toDayOfMonth(time_t t) const { return find(t).day_of_month; }
/// номер недели, начиная с какой-то недели в прошлом; неделя начинается с понедельника
/// (переводим к понедельнику и делим DayNum на 7; будем исходить из допущения,
/// что в области применения этой функции не было и не будет недель, состоящих не из семи дней)
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inline unsigned toRelativeWeekNum(DayNum_t d) const
{
return (d + 8 - lut[d].day_of_week) / 7;
}
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inline unsigned toRelativeWeekNum(time_t t) const
{
size_t index = findIndex(t);
return (index + 8 - lut[index].day_of_week) / 7;
}
/// номер месяца, начиная с какого-то месяца в прошлом (год * 12 + номер месяца в году)
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inline unsigned toRelativeMonthNum(DayNum_t d) const
{
return lut[d].year * 12 + lut[d].month;
}
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inline unsigned toRelativeMonthNum(time_t t) const
{
size_t index = findIndex(t);
return lut[index].year * 12 + lut[index].month;
}
/// делим unix timestamp на 3600;
/// (таким образом, учитываются прошедшие интервалы времени длительностью в час, не зависимо от перевода стрелок;
/// поддерживаются только часовые пояса, в которых перевод стрелок осуществлялся только на целое число часов)
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inline time_t toRelativeHourNum(time_t t) const
{
return t / 3600;
}
/// делим unix timestamp на 60
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inline time_t toRelativeMinuteNum(time_t t) const
{
return t / 60;
}
/// округление вниз до понедельника
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inline time_t toFirstDayOfWeek(time_t t) const
{
size_t index = findIndex(t);
return lut[index - (lut[index].day_of_week - 1)].date;
}
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inline DayNum_t toFirstDayNumOfWeek(DayNum_t d) const
{
return DayNum_t(d - (lut[d].day_of_week - 1));
}
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inline DayNum_t toFirstDayNumOfWeek(time_t t) const
{
size_t index = findIndex(t);
return DayNum_t(index - (lut[index].day_of_week - 1));
}
/// округление вниз до первого числа месяца
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inline time_t toFirstDayOfMonth(time_t t) const
{
size_t index = findIndex(t);
return lut[index - (lut[index].day_of_month - 1)].date;
}
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inline DayNum_t toFirstDayNumOfMonth(DayNum_t d) const
{
return DayNum_t(d - (lut[fixDay(d)].day_of_month - 1));
}
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inline DayNum_t toFirstDayNumOfMonth(time_t t) const
{
size_t index = findIndex(t);
return DayNum_t(index - (lut[index].day_of_month - 1));
}
/// округление до первого числа квартала
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inline time_t toFirstDayOfQuarter(time_t t) const
{
size_t index = findIndex(t);
switch (lut[index].month % 3)
{
case 0:
index = index - lut[index].day_of_month;
case 2:
index = index - lut[index].day_of_month;
case 1:
index = index - lut[index].day_of_month + 1;
}
return DayNum_t(index);
}
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inline DayNum_t toFirstDayNumOfQuarter(DayNum_t d) const
{
size_t index = fixDay(d);
switch (lut[index].month % 3)
{
case 0:
index = index - lut[index].day_of_month;
case 2:
index = index - lut[index].day_of_month;
case 1:
index = index - lut[index].day_of_month + 1;
}
return DayNum_t(index);
}
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inline DayNum_t toFirstDayNumOfQuarter(time_t t) const
{
size_t index = findIndex(t);
switch (lut[index].month % 3)
{
case 0:
index = index - lut[index].day_of_month;
case 2:
index = index - lut[index].day_of_month;
case 1:
index = index - lut[index].day_of_month + 1;
}
return DayNum_t(index);
}
/// округление вниз до первого числа года
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inline time_t toFirstDayOfYear(time_t t) const
{
return lut[years_lut[lut[findIndex(t)].year - DATE_LUT_MIN_YEAR]].date;
}
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inline DayNum_t toFirstDayNumOfYear(DayNum_t d) const
{
return years_lut[lut[fixDay(d)].year - DATE_LUT_MIN_YEAR];
}
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inline time_t toFirstDayNumOfYear(time_t t) const
{
return lut[years_lut[lut[findIndex(t)].year - DATE_LUT_MIN_YEAR]].date;
}
/// первое число следующего месяца
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inline time_t toFirstDayOfNextMonth(time_t t) const
{
size_t index = findIndex(t);
index += 32 - lut[index].day_of_month;
return lut[index - (lut[index].day_of_month - 1)].date;
}
/// первое число предыдущего месяца
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inline time_t toFirstDayOfPrevMonth(time_t t) const
{
size_t index = findIndex(t);
index -= lut[index].day_of_month;
return lut[index - (lut[index].day_of_month - 1)].date;
}
/// количество дней в месяце
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inline size_t daysInMonth(time_t t) const
{
size_t today = findIndex(t);
size_t start_of_month = today - (lut[today].day_of_month - 1);
size_t next_month = start_of_month + 31;
size_t start_of_next_month = next_month - (lut[next_month].day_of_month - 1);
return start_of_next_month - start_of_month;
}
/** Округление до даты; затем сдвиг на указанное количество дней.
* Замечание: результат сдвига должен находиться в пределах LUT.
*/
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inline time_t toDateAndShift(time_t t, int days = 1) const
{
return lut[findIndex(t) + days].date;
}
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inline time_t toTime(time_t t) const
{
size_t index = findIndex(t);
time_t res = t - lut[index].date;
if (res >= lut[index].time_at_offset_change)
res += lut[index].amount_of_offset_change;
return res - offset_at_start_of_epoch; /// Отсчёт от 1970-01-01 00:00:00 по локальному времени
}
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inline unsigned toHour(time_t t) const
{
size_t index = findIndex(t);
time_t res = t - lut[index].date;
if (res >= lut[index].time_at_offset_change)
res += lut[index].amount_of_offset_change;
return res / 3600;
}
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inline unsigned toMinute(time_t t) const { return ((t - find(t).date) % 3600) / 60; }
inline unsigned toSecond(time_t t) const { return (t - find(t).date) % 60; }
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inline unsigned toStartOfMinute(time_t t) const
{
time_t date = find(t).date;
return date + (t - date) / 60 * 60;
}
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inline unsigned toStartOfHour(time_t t) const
{
time_t date = find(t).date;
return date + (t - date) / 3600 * 3600;
}
/** Только для часовых поясов, отличающихся от UTC на значение, кратное часу и без перевода стрелок не значение не кратное часу */
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inline unsigned toMinuteInaccurate(time_t t) const { return (t / 60) % 60; }
inline unsigned toSecondInaccurate(time_t t) const { return t % 60; }
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inline unsigned toStartOfMinuteInaccurate(time_t t) const { return t / 60 * 60; }
inline unsigned toStartOfFiveMinuteInaccurate(time_t t) const { return t / 300 * 300; }
inline unsigned toStartOfHourInaccurate(time_t t) const { return t / 3600 * 3600; }
/// Номер дня в пределах UNIX эпохи (и немного больше) - позволяет хранить дату в двух байтах
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inline DayNum_t toDayNum(time_t t) const { return static_cast<DayNum_t>(findIndex(t)); }
inline time_t fromDayNum(DayNum_t d) const { return lut[fixDay(d)].date; }
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inline time_t toDate(DayNum_t d) const { return lut[fixDay(d)].date; }
inline unsigned toMonth(DayNum_t d) const { return lut[fixDay(d)].month; }
inline unsigned toYear(DayNum_t d) const { return lut[fixDay(d)].year; }
inline unsigned toDayOfWeek(DayNum_t d) const { return lut[fixDay(d)].day_of_week; }
inline unsigned toDayOfMonth(DayNum_t d) const { return lut[fixDay(d)].day_of_month; }
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inline const Values & getValues(DayNum_t d) const { return lut[fixDay(d)]; }
inline const Values & getValues(time_t t) const { return lut[findIndex(t)]; }
/// получает DayNum_t из года, месяца, дня
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inline DayNum_t makeDayNum(short year, char month, char day_of_month) const
{
if (unlikely(year < DATE_LUT_MIN_YEAR || year > DATE_LUT_MAX_YEAR || month < 1 || month > 12 || day_of_month < 1 || day_of_month > 31))
return DayNum_t(0);
DayNum_t any_day_of_month(years_lut[year - DATE_LUT_MIN_YEAR] + 31 * (month - 1));
return DayNum_t(any_day_of_month - toDayOfMonth(any_day_of_month) + day_of_month);
}
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inline time_t makeDate(short year, char month, char day_of_month) const
{
return lut[makeDayNum(year, month, day_of_month)].date;
}
/** Does not accept daylight saving time as argument: in case of ambiguity, it choose greater timestamp.
*/
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inline time_t makeDateTime(short year, char month, char day_of_month, char hour, char minute, char second) const
{
size_t index = makeDayNum(year, month, day_of_month);
time_t time_offset = hour * 3600 + minute * 60 + second;
if (time_offset >= lut[index].time_at_offset_change)
time_offset -= lut[index].amount_of_offset_change;
return lut[index].date + time_offset;
}
inline UInt32 toNumYYYYMM(time_t t) const
{
const Values & values = find(t);
return values.year * 100 + values.month;
}
inline UInt32 toNumYYYYMM(DayNum_t d) const
{
const Values & values = lut[fixDay(d)];
return values.year * 100 + values.month;
}
inline UInt32 toNumYYYYMMDD(time_t t) const
{
const Values & values = find(t);
return values.year * 10000 + values.month * 100 + values.day_of_month;
}
inline UInt32 toNumYYYYMMDD(DayNum_t d) const
{
const Values & values = lut[fixDay(d)];
return values.year * 10000 + values.month * 100 + values.day_of_month;
}
inline time_t YYYYMMDDToDate(UInt32 num) const
{
return makeDate(num / 10000, num / 100 % 100, num % 100);
}
inline DayNum_t YYYYMMDDToDayNum(UInt32 num) const
{
return makeDayNum(num / 10000, num / 100 % 100, num % 100);
}
inline UInt64 toNumYYYYMMDDhhmmss(time_t t) const
{
const Values & values = find(t);
return
toSecondInaccurate(t)
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+ toMinuteInaccurate(t) * 100
+ toHour(t) * 10000
+ UInt64(values.day_of_month) * 1000000
+ UInt64(values.month) * 100000000
+ UInt64(values.year) * 10000000000;
}
inline time_t YYYYMMDDhhmmssToTime(UInt64 num) const
{
return makeDateTime(
num / 10000000000,
num / 100000000 % 100,
num / 1000000 % 100,
num / 10000 % 100,
num / 100 % 100,
num % 100);
}
inline std::string timeToString(time_t t) const
{
const Values & values = find(t);
std::string s {"0000-00-00 00:00:00"};
s[0] += values.year / 1000;
s[1] += (values.year / 100) % 10;
s[2] += (values.year / 10) % 10;
s[3] += values.year % 10;
s[5] += values.month / 10;
s[6] += values.month % 10;
s[8] += values.day_of_month / 10;
s[9] += values.day_of_month % 10;
auto hour = toHour(t);
auto minute = toMinuteInaccurate(t);
auto second = toSecondInaccurate(t);
s[11] += hour / 10;
s[12] += hour % 10;
s[14] += minute / 10;
s[15] += minute % 10;
s[17] += second / 10;
s[18] += second % 10;
return s;
}
inline std::string dateToString(time_t t) const
{
const Values & values = find(t);
std::string s {"0000-00-00"};
s[0] += values.year / 1000;
s[1] += (values.year / 100) % 10;
s[2] += (values.year / 10) % 10;
s[3] += values.year % 10;
s[5] += values.month / 10;
s[6] += values.month % 10;
s[8] += values.day_of_month / 10;
s[9] += values.day_of_month % 10;
return s;
}
inline std::string dateToString(DayNum_t d) const
{
const Values & values = lut[fixDay(d)];
std::string s {"0000-00-00"};
s[0] += values.year / 1000;
s[1] += (values.year / 100) % 10;
s[2] += (values.year / 10) % 10;
s[3] += values.year % 10;
s[5] += values.month / 10;
s[6] += values.month % 10;
s[8] += values.day_of_month / 10;
s[9] += values.day_of_month % 10;
return s;
}
};