time

The time function in nexuslua provides the elapsed duration since the Unix epoch, January 1, 1970, measured in units of 0.00000001 seconds (i.e., 10 nanoseconds per tick). The actual precision of this function is platform-dependent, as it is based on the underlying implementation of std::chrono::high_resolution_clock.

Example 1: Time difference in ticks

local t1 = time()
local t2 = time()
print(t2-t1)

Result:

6

Example 2: Calculate the current date (UTC)

local function isLeapYear(year)
    if year % 400 == 0 then
        return true
    elseif year % 100 == 0 then
        return false
    elseif year % 4 == 0 then
        return true
    else
        return false
    end
end
 
local SECONDS_PER_DAY = 60 * 60 * 24
local DAYS_IN_MONTH = {31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31}
 
local function calculateDate(seconds_since_1970)
    local days_since_1970 = math.floor(seconds_since_1970 / SECONDS_PER_DAY)
    local year = 1970
    while days_since_1970 >= (isLeapYear(year) and 366 or 365) do
        days_since_1970 = days_since_1970 - (isLeapYear(year) and 366 or 365)
        year = year + 1
    end
    if isLeapYear(year) then
        DAYS_IN_MONTH[2] = 29
    else
        DAYS_IN_MONTH[2] = 28
    end
    local month = 1
    while days_since_1970 >= DAYS_IN_MONTH[month] do
        days_since_1970 = days_since_1970 - DAYS_IN_MONTH[month]
        month = month + 1
    end
    local day = days_since_1970 + 1
 
    local remainingSeconds = seconds_since_1970 % SECONDS_PER_DAY
    local hour = math.floor(remainingSeconds / 3600)
    remainingSeconds = remainingSeconds % 3600
    local minute = math.floor(remainingSeconds / 60)
    local second = remainingSeconds % 60
 
    return year, month, day, hour, minute, second
end
 
local seconds_since_1970 = time() * 0.00000001
year, month, day, hour, minutes, seconds = calculateDate(seconds_since_1970)
print(year, month, day, hour, minutes, seconds)

Result:

2023 8 10 23 42 33.255145549774