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Attempt to simplify code

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This commit is contained in:
Alexey Milovidov 2021-03-04 03:35:23 +03:00
parent 9f3760e1e3
commit 31010624d6
1 changed files with 9 additions and 17 deletions
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26
base/common/DateLUTImpl.h
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@ -8,20 +8,23 @@
#include <string>
#define DATE_LUT_MAX (0xFFFFFFFFU - 86400)
#define DATE_LUT_MAX_DAY_NUM (0xFFFFFFFFU / 86400)
/// Table size is bigger than DATE_LUT_MAX_DAY_NUM to fill all indices within UInt16 range: this allows to remove extra check.
#define DATE_LUT_SIZE 0x20000
#define DATE_LUT_MIN_YEAR 1925 /// 1925 since wast majority of timezones changed to 15-minute aligned offsets somewhere in 1924 or earlier.
#define DATE_LUT_MAX_YEAR 2283 /// Last supported year (complete)
#define DATE_LUT_YEARS (1 + DATE_LUT_MAX_YEAR - DATE_LUT_MIN_YEAR) /// Number of years in lookup table
#define DATE_LUT_SIZE 0x20000
#define DATE_LUT_MAX (0xFFFFFFFFU - 86400)
#define DATE_LUT_MAX_DAY_NUM 0xFFFF
#if defined(__PPC__)
#if !__clang__
#pragma GCC diagnostic ignored "-Wmaybe-uninitialized"
#endif
#endif
/// Flags for toYearWeek() function.
enum class WeekModeFlag : UInt8
{
@ -208,17 +211,14 @@ private:
/// UTC offset is from -12 to +14 in all known time zones. This requires checking only three indices.
if (t >= lut[guess].date && t < lut[UInt32(guess + 1)].date)
return LUTIndex{guess};
return LUTIndex(guess);
/// Time zones that have offset 0 from UTC do daylight saving time change (if any)
/// towards increasing UTC offset (example: British Standard Time).
if (t >= lut[UInt32(guess + 1)].date)
return LUTIndex(guess + 1);
if (lut[guess - 1].date <= t)
return LUTIndex(guess - 1);
return LUTIndex(guess - 2);
return LUTIndex(guess - 1);
}
inline LUTIndex toLUTIndex(DayNum d) const
@ -388,9 +388,6 @@ public:
{
const LUTIndex index = findIndex(t);
if (unlikely(index > DATE_LUT_MAX_DAY_NUM))
return t + offset_at_start_of_epoch;
time_t res = t - lut[index].date;
if (res >= lut[index].time_at_offset_change())
@ -403,11 +400,6 @@ public:
{
const LUTIndex index = findIndex(t);
/// If it is overflow case,
/// than limit number of hours to avoid insane results like 1970-01-01 89:28:15
if (unlikely(index > DATE_LUT_MAX_DAY_NUM))
return static_cast<unsigned>((t + offset_at_start_of_epoch) / 3600) % 24;
time_t time = t - lut[index].date;
/// Data is cleaned to avoid possibility of underflow.