mirror of
https://github.com/ClickHouse/ClickHouse.git
synced 2024-11-22 07:31:57 +00:00
2d03d330bc
The Year 1925 is a starting point because most of the timezones switched to saner (mostly 15-minutes based) offsets somewhere during 1924 or before. And that significantly simplifies implementation. 2238 is to simplify arithmetics for sanitizing LUT index access; there are less than 0x1ffff days from 1925. * Extended DateLUTImpl internal LUT to 0x1ffff items, some of which represent negative (pre-1970) time values. As a collateral benefit, Date now correctly supports dates up to 2149 (instead of 2106). * Added a new strong typedef ExtendedDayNum, which represents dates pre-1970 and post 2149. * Functions that used to return DayNum now return ExtendedDayNum. * Refactored DateLUTImpl to untie DayNum from the dual role of being a value and an index (due to negative time). Index is now a different type LUTIndex with explicit conversion functions from DatNum, time_t, and ExtendedDayNum. * Updated DateLUTImpl to properly support values close to epoch start (1970-01-01 00:00), including negative ones. * Reduced resolution of DateLUTImpl::Values::time_at_offset_change to multiple of 15-minutes to allow storing 64-bits of time_t in DateLUTImpl::Value while keeping same size. * Minor performance updates to DateLUTImpl when building month LUT by skipping non-start-of-month days. * Fixed extractTimeZoneFromFunctionArguments to work correctly with DateTime64. * New unit-tests and stateless integration tests for both DateTime and DateTime64.
58 lines
1.6 KiB
C++
58 lines
1.6 KiB
C++
#pragma once
|
|
|
|
#include "DateLUTImpl.h"
|
|
|
|
#include "defines.h"
|
|
|
|
#include <boost/noncopyable.hpp>
|
|
|
|
#include <atomic>
|
|
#include <memory>
|
|
#include <mutex>
|
|
#include <unordered_map>
|
|
|
|
|
|
/// This class provides lazy initialization and lookup of singleton DateLUTImpl objects for a given timezone.
|
|
class DateLUT : private boost::noncopyable
|
|
{
|
|
public:
|
|
/// Return singleton DateLUTImpl instance for the default time zone.
|
|
static ALWAYS_INLINE const DateLUTImpl & instance()
|
|
{
|
|
const auto & date_lut = getInstance();
|
|
return *date_lut.default_impl.load(std::memory_order_acquire);
|
|
}
|
|
|
|
/// Return singleton DateLUTImpl instance for a given time zone.
|
|
static ALWAYS_INLINE const DateLUTImpl & instance(const std::string & time_zone)
|
|
{
|
|
const auto & date_lut = getInstance();
|
|
if (time_zone.empty())
|
|
return *date_lut.default_impl.load(std::memory_order_acquire);
|
|
|
|
return date_lut.getImplementation(time_zone);
|
|
}
|
|
static void setDefaultTimezone(const std::string & time_zone)
|
|
{
|
|
auto & date_lut = getInstance();
|
|
const auto & impl = date_lut.getImplementation(time_zone);
|
|
date_lut.default_impl.store(&impl, std::memory_order_release);
|
|
}
|
|
|
|
protected:
|
|
DateLUT();
|
|
|
|
private:
|
|
static DateLUT & getInstance();
|
|
|
|
const DateLUTImpl & getImplementation(const std::string & time_zone) const;
|
|
|
|
using DateLUTImplPtr = std::unique_ptr<DateLUTImpl>;
|
|
|
|
/// Time zone name -> implementation.
|
|
mutable std::unordered_map<std::string, DateLUTImplPtr> impls;
|
|
mutable std::mutex mutex;
|
|
|
|
std::atomic<const DateLUTImpl *> default_impl;
|
|
};
|