--- a/src/video/SDL_surface.c	Sat Mar 02 16:50:35 2002 +0000
+++ b/src/video/SDL_surface.c	Tue Mar 05 19:55:32 2002 +0000
@@ -630,6 +630,10 @@
  */
 int SDL_LockSurface (SDL_Surface *surface)
 {
+	if ( surface->locked < 0 ) {
+		SDL_SetError("Surface has a rectangle lock");
+		return(-1);
+	}
 	if ( ! surface->locked ) {
 		/* Perform the lock */
 		if ( surface->flags & (SDL_HWSURFACE|SDL_ASYNCBLIT) ) {
@@ -653,6 +657,78 @@
 	/* Ready to go.. */
 	return(0);
 }
+int SDL_LockRect (SDL_Surface *surface, SDL_Rect *rect, void **pixels, int *pitch)
+{
+	int retval = 0;
+
+	/* Check to see if the surface is already locked */
+	*pixels = NULL;
+	if ( surface->locked != 0 ) {
+		SDL_SetError("Surface is already locked");
+		return(-1);
+	}
+
+	/* Clip the lock to the clipping rectangle of the surface */
+	{
+	        SDL_Rect *clip = &surface->clip_rect;
+		int dx, dy;
+		int h = rect->h;
+		int w = rect->w;
+
+		dx = clip->x - rect->x;
+		if(dx > 0) {
+			w -= dx;
+			rect->x += dx;
+		}
+		dx = rect->x + w - clip->x - clip->w;
+		if(dx > 0)
+			w -= dx;
+
+		dy = clip->y - rect->y;
+		if(dy > 0) {
+			h -= dy;
+			rect->y += dy;
+		}
+		dy = rect->y + h - clip->y - clip->h;
+		if(dy > 0)
+			h -= dy;
+
+		if(w > 0 && h > 0) {
+			rect->w = w;
+			rect->h = h;
+		} else {
+			rect->w = 0;
+			rect->h = 0;
+			SDL_SetError("Rectangle was clipped");
+			return(-1);
+		}
+	}
+
+	/* Perform the lock */
+	if ( surface->flags & (SDL_HWSURFACE|SDL_ASYNCBLIT) ) {
+		SDL_VideoDevice *video = current_video;
+		SDL_VideoDevice *this  = current_video;
+		if ( video->LockHWSurfaceRect ) {
+			retval = video->LockHWSurfaceRect(this, surface, rect, pixels, pitch);
+			if ( retval == 0 ) {
+				surface->locked = -1;
+				return 0;
+			}
+		}
+	}
+	if ( SDL_MUSTLOCK(surface) ) {
+		retval = SDL_LockSurface(surface);
+		if ( retval < 0 ) {
+			return retval;
+		}
+	}
+	surface->locked = -1;
+	*pixels = (Uint8 *)surface->pixels + rect->y * surface->pitch + rect->x * surface->format->BytesPerPixel;
+	*pitch = surface->pitch;
+
+	/* Ready to go.. */
+	return(0);
+}
 /*
  * Unlock a previously locked surface
  * -- Do not call this from any blit function, as SDL_DrawCursor() may recurse
@@ -663,6 +739,9 @@
 void SDL_UnlockSurface (SDL_Surface *surface)
 {
 	/* Only perform an unlock if we are locked */
+	if ( surface->locked < 0 ) {
+		return;
+	}
 	if ( ! surface->locked || (--surface->locked > 0) ) {
 		return;
 	}
@@ -683,6 +762,29 @@
 		}
 	}
 }
+void SDL_UnlockRect (SDL_Surface *surface)
+{
+	/* Only perform an unlock if we are locked */
+	if ( surface->locked != -1 ) {
+		return;
+	}
+
+	/* Perform the unlock */
+	if ( surface->flags & (SDL_HWSURFACE|SDL_ASYNCBLIT) ) {
+		SDL_VideoDevice *video = current_video;
+		SDL_VideoDevice *this  = current_video;
+		if ( video->LockHWSurfaceRect ) {
+			video->UnlockHWSurfaceRect(this, surface);
+			return;
+		}
+	}
+	if ( SDL_MUSTLOCK(surface) ) {
+		surface->locked = 1;
+		SDL_UnlockSurface(surface);
+	} else {
+		surface->locked = 0;
+	}
+}
 
 /* 
  * Convert a surface into the specified pixel format.