ClickHouse/libs/libcommon/include/common/LocalDateTime.h
2018-07-18 22:04:01 +03:00

195 lines
5.5 KiB
C++

#pragma once
#include <string>
#include <iomanip>
#include <exception>
#include <common/DateLUT.h>
#include <common/LocalDate.h>
/** Stores calendar date and time in broken-down form.
* Could be initialized from date and time in text form like '2011-01-01 00:00:00' or from time_t.
* Could be implicitly casted to time_t.
* NOTE: Transforming between time_t and LocalDate is done in local time zone!
*
* When local time was shifted backwards (due to daylight saving time or whatever reason)
* - then to resolve the ambiguity of transforming to time_t, lowest of two possible values is selected.
*/
class LocalDateTime
{
private:
unsigned short m_year;
unsigned char m_month;
unsigned char m_day;
unsigned char m_hour;
unsigned char m_minute;
unsigned char m_second;
/// For struct to fill 8 bytes and for safe invocation of memcmp.
/// NOTE We may use attribute packed instead, but it is less portable.
unsigned char pad = 0;
void init(time_t time)
{
if (unlikely(time > DATE_LUT_MAX || time == 0))
{
m_year = 0;
m_month = 0;
m_day = 0;
m_hour = 0;
m_minute = 0;
m_second = 0;
return;
}
const auto & date_lut = DateLUT::instance();
const auto & values = date_lut.getValues(time);
m_year = values.year;
m_month = values.month;
m_day = values.day_of_month;
m_hour = date_lut.toHour(time);
m_minute = date_lut.toMinute(time);
m_second = date_lut.toSecond(time);
(void)pad; /// Suppress unused private field warning.
}
void init(const char * s, size_t length)
{
if (length < 19)
throw std::runtime_error("Cannot parse LocalDateTime: " + std::string(s, length));
m_year = (s[0] - '0') * 1000 + (s[1] - '0') * 100 + (s[2] - '0') * 10 + (s[3] - '0');
m_month = (s[5] - '0') * 10 + (s[6] - '0');
m_day = (s[8] - '0') * 10 + (s[9] - '0');
m_hour = (s[11] - '0') * 10 + (s[12] - '0');
m_minute = (s[14] - '0') * 10 + (s[15] - '0');
m_second = (s[17] - '0') * 10 + (s[18] - '0');
(void)pad;
}
public:
explicit LocalDateTime(time_t time)
{
init(time);
}
LocalDateTime(unsigned short year_, unsigned char month_, unsigned char day_,
unsigned char hour_, unsigned char minute_, unsigned char second_)
: m_year(year_), m_month(month_), m_day(day_), m_hour(hour_), m_minute(minute_), m_second(second_)
{
}
explicit LocalDateTime(const std::string & s)
{
if (s.size() < 19)
throw std::runtime_error("Cannot parse LocalDateTime: " + s);
init(s.data(), s.size());
}
LocalDateTime() : m_year(0), m_month(0), m_day(0), m_hour(0), m_minute(0), m_second(0)
{
}
LocalDateTime(const char * data, size_t length)
{
init(data, length);
}
LocalDateTime(const LocalDateTime &) noexcept = default;
LocalDateTime & operator= (const LocalDateTime &) noexcept = default;
LocalDateTime & operator= (time_t time)
{
init(time);
return *this;
}
operator time_t() const
{
return m_year == 0
? 0
: DateLUT::instance().makeDateTime(m_year, m_month, m_day, m_hour, m_minute, m_second);
}
unsigned short year() const { return m_year; }
unsigned char month() const { return m_month; }
unsigned char day() const { return m_day; }
unsigned char hour() const { return m_hour; }
unsigned char minute() const { return m_minute; }
unsigned char second() const { return m_second; }
void year(unsigned short x) { m_year = x; }
void month(unsigned char x) { m_month = x; }
void day(unsigned char x) { m_day = x; }
void hour(unsigned char x) { m_hour = x; }
void minute(unsigned char x) { m_minute = x; }
void second(unsigned char x) { m_second = x; }
LocalDate toDate() const { return LocalDate(m_year, m_month, m_day); }
LocalDateTime toStartOfDate() { return LocalDateTime(m_year, m_month, m_day, 0, 0, 0); }
bool operator< (const LocalDateTime & other) const
{
return 0 > memcmp(this, &other, sizeof(*this));
}
bool operator> (const LocalDateTime & other) const
{
return 0 < memcmp(this, &other, sizeof(*this));
}
bool operator<= (const LocalDateTime & other) const
{
return 0 >= memcmp(this, &other, sizeof(*this));
}
bool operator>= (const LocalDateTime & other) const
{
return 0 <= memcmp(this, &other, sizeof(*this));
}
bool operator== (const LocalDateTime & other) const
{
return 0 == memcmp(this, &other, sizeof(*this));
}
bool operator!= (const LocalDateTime & other) const
{
return !(*this == other);
}
};
static_assert(sizeof(LocalDateTime) == 8);
inline std::ostream & operator<< (std::ostream & ostr, const LocalDateTime & datetime)
{
ostr << std::setfill('0') << std::setw(4) << datetime.year();
ostr << '-' << (datetime.month() / 10) << (datetime.month() % 10)
<< '-' << (datetime.day() / 10) << (datetime.day() % 10)
<< ' ' << (datetime.hour() / 10) << (datetime.hour() % 10)
<< ':' << (datetime.minute() / 10) << (datetime.minute() % 10)
<< ':' << (datetime.second() / 10) << (datetime.second() % 10);
return ostr;
}
namespace std
{
inline string to_string(const LocalDateTime & datetime)
{
stringstream str;
str << datetime;
return str.str();
}
}