gistfile1.js

/**
 * String reverse bench test script.
 * Runs in javascript shell, see print() function
 */



/** make a 1MB string */
function bigString(){
	var s = '';
	for( var i = 0; i < 131072; i++ ){
		s += '12345678';
	}
	return s;
}


/** make a 1KB string */
function smallString(){
	var s = '';
	for( var i = 0; i < 128; i++ ){
		s += '12345678';
	}
	return s;
}


/** simple timer to show results */
var Timer = function(){
	this.t1 = (new Date).getTime();
}
Timer.prototype.stop = function( s ){
	var t2 = (new Date).getTime();
	var t = t2 - this.t1;
	print( '"'+s.slice(0,8)+' ... "' );
	print( ' > ' +t+ ' milliseconds');
}



/** function 1 */
function reverse_1( s ){
	var r = '';
	while( s ){
		r += s.substr(-1,1);
		s = s.slice(0,-1);
	}
	return r;
}


/** function 2 */
function reverse_2(){
	var r = '', i = 0, n = - s.length;
	while( i > n ){
		r += s.substr(--i,1);
	}
	return r;
}


/** function 3 */
function reverse_3(){
	var r = '', n = 0, len = s.length;
	while( r.length < len ){
		r += s.substr(--n,1);
	}
	return r;
}


//var s = '12345678';
//var s = smallString();
var s = bigString();


// run test 1
var t = new Timer;
var r = reverse_1(s);
t.stop( r );


// run test 2
var t = new Timer;
var r = reverse_2(s);
t.stop( r );


// run test 3
var t = new Timer;
var r = reverse_3(s);
t.stop( r );