Implicit signed-to-unsigned conversions in rasterfill.cpp

[akhliustov]

1. http://trac.osgeo.org/gdal/browser/trunk/gdal/alg/rasterfill.cpp#L571
   
   

if( iY - panLastY[iX] <= dfMaxSearchDist )

panLastY[iX] is unsigned, so iY - panLastY[iX] is unsigned too. If iY < panLastY[iX], their "difference" is a large positive number that can be greater than dfMaxSearchDist. In that case the condition evaluates to false, which is (probably) not expected.

2. http://trac.osgeo.org/gdal/browser/trunk/gdal/alg/rasterfill.cpp#L333
   
   double dfDistSq = ((target_x-origin_x) * (target_x-origin_x)) + ((target_y-origin_y) * (target_y-origin_y));
   
   Here target_y is unsigned, so the whole right-hand expression uses unsigned arithmetics. If target_x < origin_x or target_y < origin_y, it leads to a totally wrong result.