LuaClasses/Stopwatch.lua

--luaClasses/Stopwatch.lua
--Matthew Ellison
-- Created: 02-01-19
--Modified: 02-08-19
--This is a simple class to be used to time runtimes of various things within programs


--You need some kind of table to hold the times
Stopwatch = {}
Stopwatch.__index = Stopwatch;

--This is needed to create a Stopwatch and link the variables and functions
--It should be called before anything else when createing a Stopwatch
function Stopwatch:create()
	local timer = {
		startTime = nil,
		stopTime = nil
	};
	setmetatable(timer, Stopwatch);	--This links the new variable with the functions from the Stopwatch
	return timer;
end

--This function gets the start time to simulate actually hitting the button on a stopwatch
function Stopwatch:start()
	self.stopTime = nil;	--Make sure it knows that the clock is still running
	--Setting the clock last puts the time closer to the actual start of the thing you are trying to time
	self.startTime = os.clock();	--Get the current time
end

--This function gets the stop time to simulate actually hitting the stop button on a stopwatch
function Stopwatch:stop()
	--Set the time first, for efficiency sake
	self.stopTime = os.clock();
	--Make sure the clock had been started
	if(startTime == nil) then
		--If not unset the stop time
		stopTime = nil;
	end
end

--This function resets all the variables. It is used if you want to use the same timer for multiple tests, but it shouldn't be necessary. Use to avoid unforseen bugs
function Stopwatch:reset()
	self.startTime = nil;
	self.stopTime = nil;
end

--Returns the difference in the time at the default time resolution
--Mostly called from the other get___ functions
function Stopwatch:getTime()
	local timeDifference = nil;
	--If start and stop has been called return the difference
	if((self.startTime ~= nil) and (self.stopTime ~= nil)) then
		timeDifference = self.stopTime - self.startTime;
	--If start has been called but stop hasn't make the current time the end time. This simulates looking at a stopwatch while it is still running
	elseif((self.startTime ~= nil) and (self.stopTime == nil)) then
		timeDifference = os.time() - self.startTime;
	--Otherwise return -1 as an error
	else
		timeDifference = -1;
	end
	--Return the number generated
	return timeDifference;
end

--This function returns the duration the stopwatch has run in microseconds
function Stopwatch:getMicroseconds()
	local timeDifference = self:getTime();	--Get the time that has elapsed
	--If you did not get an error convert the time to microseconds
	if(timeDifference >= 0) then
		timeDifference = timeDifference * 1000000;
	end
	return timeDifference;
end

--This function returns the duration the stopwatch has run in milliseconds
function Stopwatch:getMilliseconds()
	local timeDifference = self:getTime();	--Get the time that has elapsed
	--If you did not get an error convert the time to milliseconds
	if(timeDifference >= 0) then
		timeDifference = timeDifference * 1000;
	end
	return timeDifference;
end

--This function returns the duration the stopwatch has run in seconds
function Stopwatch:getSeconds()
	--The function returns in seconds by default
	return self:getTime();
end

--This function returns the duration the stopwatch has run in minutes
function Stopwatch:getMinutes()
	local timeDifference = self:getTime();
	--If you did not get an error conver the time to minutes
	if(timeDifference >= 0) then
		timeDifference = timeDifference / 60;
	end
	return timeDifference;
end