+/* lossless_d.c */
+int lossless_undoscanline( pixel *psl, pixel *sl, int no, int color);
+int lossless_undoscanline_pixel(pixel *psl, pixel *sl, int no);
+
+/* lossy_d.c */
+int lossy_undoscanline( pixel *psl, pixel *sl, int no, int color);
+int lossy_undoscanline_pixel( pixel *psl, pixel *sl, int no);
+
+