DZone Snippets: timer code

TimeLine //JavaScript Class

jonasraoni (Jonas Raoni Soares Silva) — Sun, 30 Mar 2008 16:49:21 GMT

Simulates the Adobe Flash timeline. You define the amount of frames, the speed in fps (frames per second) and, at each frame passage an event is called, useful for animations.

[UPDATED CODE AND HELP CAN BE FOUND HERE]



//+ Jonas Raoni Soares Silva

//@ http://jsfromhell.com/classes/timeline [v1.0]



TimeLine = function(fps, f){

	this.fps = fps, this.frames = f;

};

with({o: TimeLine, $: TimeLine.prototype}){

	o.timers = [];

	$.running = !!($.current = +(o.timer = $.time = null));

	o.run = function(){

		var o = this;

		o.timer || (o.timer = setInterval(function(){

			for(var h, d = +(new Date), t = o.timers, i = t.length; i--;){

				(!t[i].running || ((d - t[i].time) / (1e3 / t[i].fps) > t[i].current + 1 &&

				t[i].onframe(++t[i].current), t[i].current >= t[i].frames)) &&

				(h = t.splice(i, 1)[0], h.stop(1));

			}

		}, 1));

	};

	$.start = function(c){

		var o = this, t = TimeLine;

		if(o.running) return;

		o.running = true, o.current = c || 0;

		o.time = new Date, o.onstart && o.onstart();

		if(!o.onframe || o.frames <= 0 || o.fps <= 0)

			return o.stop(1);

		t.timers.push(this), t.run();

	};

	$.stop = function(){

		var o = this;

		o.running = false;

		if(!TimeLine.timers.length)

			TimeLine.timer = clearInterval(TimeLine.timer), null;

		arguments.length && o.onstop && o.onstop();

	};

}

Example





25 fps

12 fps



TimeLine working together with the ease in quad function.

Measuring the elapsed time

jrobertson (James Robertson) — Fri, 14 Mar 2008 08:47:16 GMT

This Ruby code measures how long it takes to display the message "hello world".



def test_method(statement)

  start_time = Time.now

  eval(statement)

  end_time = Time.now

  end_time - start_time

end



statement = "sleep 1.5; puts 'hello world'"

elapsed_time = test_method(statement)

puts "elapsed time : #{elapsed_time}"

output



hello world

elapsed time : 1.499266

Capturing the value from an HTML text box - Ajax style

jrobertson (James Robertson) — Tue, 18 Dec 2007 17:08:23 GMT

This extract of JavaScript code illustrates how the value of a text box on an HTML form could be saved efficiently when used with AJAX.



  onkeyup="timed_updateSummaryCRecord(event.keyCode, '1','project', this.value)" />

The onkeyup event retrieves the user input as soon as the key is pressed, then the event.keyCode is validated to ensure only alpha-numeric characters trigger the save routine.



function timed_updateSummaryCRecord(keyCode, parent_id, field,  val) {

  if (val.length > 0 && ((keyCode > 40) || (keyCode == 8)) ) {

    clearTimeout(t);

    t = setTimeout("updateSummaryCRecord('" + parent_id + "', '" + field + "', '" + val + "')", 1000);

  }

}

The setTimeout will trigger the save routine after 1 second, however if the user continues to type before the 1 second timer has elapsed, the running timer will be cancelled and the new timer will start.

Note: keyCode value '8' is accepted because it is the backspace key. It would also be helpful to accept the delete key press.

Code execution timer

Minimiscience (Guildorn Tanaleth) — Thu, 05 Jul 2007 03:27:35 GMT

These two bits of code can be used to record & output the execution time of a piece of code in microseconds. NOTE: The functions used here are only available on BSD-like systems (I think).



/* Put this line at the top of the file: */

#include 



/* Put this right before the code you want to time: */

struct timeval timer_start, timer_end;

gettimeofday(&timer_start, NULL);



/* Put this right after the code you want to time: */

gettimeofday(&timer_end, NULL);

double timer_spent = timer_end.tv_sec - timer_start.tv_sec + (timer_end.tv_usec - timer_start.tv_usec) / 1000000.0;

printf("Time spent: %.6f\n", timer_spent);

Time it - C

scvalex (Alexandru Scvortov) — Wed, 09 May 2007 08:31:08 GMT

This function runs another function, given as a parameter, a certain number of times and returns the number of cycles needed to complete.

Useful for timing short snippets of code.



#include 



typedef void(*FN)();



double timeit(FN f, int n) {

  clock_t start = clock();



  int i = 0;

  for (; i < n; ++i)

    f();



  return clock() - start;

}

Using Ao_timer for a better sleep

korakot (Korakot Chaovavanich) — Wed, 01 Feb 2006 08:59:10 GMT

A few of my old examples include 'unsafe' use of e32.ao_sleep().
The problem is that the sleep can't be interrupted.
I often use a convenient loop like this



while running:

  // do something

  e32.ao_sleep(1)  # sleep a sec

Now in pys60 1.3.1, it's better to use e32.Ao_timer



timer = e32.Ao_timer()

while running:

  // do something

  timer.after(1)   # sleep a sec

I can then interupt the sleep with timer.cancel()
in other part of the program if I need to continue the loop.

For example, I can end the application without waiting for
the last second.

Mobile timer app

korakot (Korakot Chaovavanich) — Sat, 01 Oct 2005 19:01:17 GMT



from appuifw import *

from key_codes import *

import e32, time



class StopWatch:

    running = 0

    time_start = None

    elap = 0.0



    def __init__(self):

        self.canvas = Canvas(self.update)

        app.body = self.canvas

        self.canvas.bind(EKeySelect, self.toggle)

        self.update()



    def update(self, rect=None):

        if self.running:

            self.elap = time.clock() - self.time_start

            e32.ao_sleep(0.05, self.update)

        t = self.elap

        min = int(t / 60)

        sec =  int(t - min*60)

        hsec = int((t - min*60 - sec)*100)

        self.canvas.clear()

        self.canvas.text((20,40), u"%02d:%02d:%02d" % (min,sec,hsec), font='title')



    def toggle(self):

        if self.running:

            self.running = 0

            self.elap = time.clock() - self.time_start

        else:

            self.running = 1

            self.time_start = time.clock() - self.elap

            self.update()



    def reset(self):

        self.running = 0

        self.elap = 0.0

        self.update()





sw = StopWatch()

lock = e32.Ao_lock()

app.menu = [(u'Reset', sw.reset), (u'Close', lock.signal)]

app.exit_key_handler = lock.signal

lock.wait()

This will run and pause, resume when you press the select key.

Use timeit module

korakot (Korakot Chaovavanich) — Mon, 05 Sep 2005 11:26:17 GMT



>>> from timeit import Timer

>>> t = Timer('md5.new("md5 is not safe").digest()', 'import md5')

>>> t.timeit()

2.6892227922821803

Quite useful to compare speed of codes.
Read more here
http://diveintopython.org/performance_tuning/timeit.html