explanation of void collision in sdl lib

I got a collision method from someone else's source, but I don't know where he learned it from (what tutorial). He says libsdl.org but I haven't been able to find it.

This is the collision method, and I don't think he made it up, so I think he got it from somewhere.

Code:

void collision()
{

           RECT rcOne, rcTwo,rcThree, rcTemp,rcTemp2;
      SetRect(&rcOne,paddle1.xpos,paddle1.ypos,paddle1.xpos+paddle1.width,paddle1.ypos+paddle1.height);
      SetRect(&rcTwo,paddle2.xpos,paddle2.ypos,paddle2.xpos+paddle2.width,paddle2.ypos+paddle2.height);
      SetRect(&rcThree,ball.xpos,ball.ypos,ball.xpos+ball.width,ball.ypos+ball.height);
        if(IntersectRect(&rcTemp,&rcOne,&rcThree))
          {

           ball.direction = 5;

          }
        if(IntersectRect(&rcTemp2,&rcTwo,&rcThree))
          {

          ball.direction = -5;

          }
        if(ball.xpos == 0)
          {
          ball.direction = 5;
          }
        if(ball.xpos == 620)
          {
          ball.direction = -5;
          }
}

if you can point me to the online location of this I will be happy, in the meantime I will continue searching for it because I really want it.
and yes I would ask him but he's gone.