define( [

"../core",
"../var/rcssNum"

], function( jQuery, rcssNum ) {

function adjustCSS( elem, prop, valueParts, tween ) {

var adjusted,
        scale = 1,
        maxIterations = 20,
        currentValue = tween ?
                function() { return tween.cur(); } :
                function() { return jQuery.css( elem, prop, "" ); },
        initial = currentValue(),
        unit = valueParts && valueParts[ 3 ] || ( jQuery.cssNumber[ prop ] ? "" : "px" ),

        // Starting value computation is required for potential unit mismatches
        initialInUnit = ( jQuery.cssNumber[ prop ] || unit !== "px" && +initial ) &&
                rcssNum.exec( jQuery.css( elem, prop ) );

if ( initialInUnit && initialInUnit[ 3 ] !== unit ) {

        // Trust units reported by jQuery.css
        unit = unit || initialInUnit[ 3 ];

        // Make sure we update the tween properties later on
        valueParts = valueParts || [];

        // Iteratively approximate from a nonzero starting point
        initialInUnit = +initial || 1;

        do {

                // If previous iteration zeroed out, double until we get *something*.
                // Use string for doubling so we don't accidentally see scale as unchanged below
                scale = scale || ".5";

                // Adjust and apply
                initialInUnit = initialInUnit / scale;
                jQuery.style( elem, prop, initialInUnit + unit );

        // Update scale, tolerating zero or NaN from tween.cur()
        // Break the loop if scale is unchanged or perfect, or if we've just had enough.
        } while (
                scale !== ( scale = currentValue() / initial ) && scale !== 1 && --maxIterations
        );
}

if ( valueParts ) {
        initialInUnit = +initialInUnit || +initial || 0;

        // Apply relative offset (+=/-=) if specified
        adjusted = valueParts[ 1 ] ?
                initialInUnit + ( valueParts[ 1 ] + 1 ) * valueParts[ 2 ] :
                +valueParts[ 2 ];
        if ( tween ) {
                tween.unit = unit;
                tween.start = initialInUnit;
                tween.end = adjusted;
        }
}
return adjusted;

}

return adjustCSS; } );