Fix invalid pointer offset types.

	* scribo/preprocessing/rotate_90.hh
	(out_next_offset, out_next_p_offset): Fix a wrong type leading to
	overflows.
	(output): Add an assertion checking its validity.

scribo/ChangeLog

+2010-08-12  Guillaume Lazzara  <z@lrde.epita.fr>
+
+	Fix invalid pointer offset types.
+
+	* scribo/preprocessing/rotate_90.hh
+	(out_next_offset, out_next_p_offset): Fix a wrong type leading to
+	overflows.
+	(output): Add an assertion checking its validity.
+
 2010-08-10  Guillaume Lazzara  <z@lrde.epita.fr>
 
 	Fix warnings with g++-4.1 in Scribo.

scribo/scribo/preprocessing/rotate_90.hh

@@ -93,6 +93,8 @@ namespace scribo
       mln_concrete(I) output(mln_domain(I)(input.domain().pmin(), pmax),
 			     input.border());
 
+      mln_assertion(output.is_valid());
+
       const mln_value(I)* in_ptr = input.buffer();
 
       unsigned in_ncols = geom::ncols(input) + 2 * input.border();
@@ -101,7 +103,7 @@ namespace scribo
       unsigned out_ncols = geom::ncols(output);
       unsigned out_nrows = geom::nrows(output);
 
-      unsigned
+      int
 	out_next_offset,
 	out_next_p_offset;