void SDL_FreeSurface (SDL_Surface *surface)
{
    /* Free anything that's not NULL, and not the screen surface */
    if ((surface == NULL) ||
        (current_video &&
        ((surface == SDL_ShadowSurface)||(surface == SDL_VideoSurface)))) {
        return;
    }
    if ( --surface->refcount > 0 ) {
        return;
    }
    while ( surface->locked > 0 ) {
        SDL_UnlockSurface(surface);
    }
    if ( (surface->flags & SDL_RLEACCEL) == SDL_RLEACCEL ) {
            SDL_UnRLESurface(surface, 0);
    }
    if ( surface->format ) {
        SDL_FreeFormat(surface->format);
        surface->format = NULL;
    }
    if ( surface->map != NULL ) {
        SDL_FreeBlitMap(surface->map);
        surface->map = NULL;
    }
    if ( surface->hwdata ) {
        SDL_VideoDevice *video = current_video;
        SDL_VideoDevice *this  = current_video;
        video->FreeHWSurface(this, surface);
    }
    if ( surface->pixels &&
         ((surface->flags & SDL_PREALLOC) != SDL_PREALLOC) ) {
        SDL_free(surface->pixels);
    }
    SDL_free(surface);
#ifdef CHECK_LEAKS
    --surfaces_allocated;
#endif
}