jsBenchmarker

Source of "loops"

/**
 * @html <p><b>warning:</b> the test is long.</p>
 */

var limit = 5e4, counter;
function action(){
	--counter;
};

Benchmarker().compare({
	attempts:10,
	times:1,
	onBeforeAttempt:function(){
		counter = limit;
	},
	onAfterAttempt:function(){
		if( counter < 0 )
			alert('this one did too many');
		else if( counter > 0 )
			alert('this one did too few');
	}
 }, {
	'for':function(){
		for( var i = 0, times = limit; i < times; i++ )
			action();
	},
	'while':function(){
		var i = 0, times = limit;
		while( i++ < times )
			action();
	},
	do_while:function(){
		var i = 0, times = limit;
		do action();
		while( ++i < times );
	},
	for_reversed:function(){
		for( var i = limit; i; i-- )
			action();
	},
	while_reversed:function(){
		var i = limit;
		while( i-- )
			action();
	},
	while_reversed_left:function(){
		var i = limit + 1;
		while( --i )
			action();
	},
	do_while_reversed:function(){
		var i = limit;
		do action();
		while( --i );
	},
	duff:function(){
		var loops = limit;
						
		while ( loops )
		    switch( loops % 4 ){
			    case 0: action(); --loops;
			    case 3: action(); --loops;
			    case 2: action(); --loops;
			    case 1: action(); --loops;                 
		    }
	},
	duff2:function(){
		var loops = limit,
			rest = loops % 4;
		
		while( rest-- )
			action( --loops );

		while( loops ){
			action(); --loops;
			action(); --loops;
			action(); --loops;
			action(); --loops;
		}
	},
	duff3:function(){
		var rest = limit % 4,
			loops = (limit - rest) / 4;
	
		while( rest-- )
			action();

		while( loops-- ){
			action();
			action();
			action();
			action();
		}	
	}
});