Actionscript 3 :: Stretching BitmapData ?

I'm trying to replicate this function from the Allegro graphics library:

void stretch_blit(BITMAP *source, BITMAP *dest, int source_x,
int source_y, int source_width, int source_height,
int dest_x, dest_y, dest_width, dest_height);

http:[url]....

This is somewhat difficult in Flash, because of the overlapping functionality between the Rectangle and Matrix arguments of AS3's BitmapData.draw() method. This is what I have so far. It only works most of the time, and is incredibly inefficient (due to having to sample pixels twice).

function stretch_blit(src:BitmapData, dest:BitmapData, source_x:int, source_y:int,
source_width:int, source_height:int, dest_x:int, dest_y:int,
dest_width:int, dest_height:int):void {[code].....