[Boost-bugs] [Boost C++ Libraries] #6072: Bad iterator difference for m.begin1() - m.end1() in ublas

Subject: [Boost-bugs] [Boost C++ Libraries] #6072: Bad iterator difference for m.begin1() - m.end1() in ublas
From: Boost C++ Libraries (noreply_at_[hidden])
Date: 2011-10-30 12:20:23

#6072: Bad iterator difference for m.begin1() - m.end1() in ublas
-----------------------------------------------------+----------------------
 Reporter:  Robin Palotai <palotai.robin@…>          |       Owner:  guwi17 
     Type:  Bugs                                     |      Status:  new    
Milestone:  To Be Determined                         |   Component:  uBLAS  
  Version:  Boost 1.47.0                             |    Severity:  Problem
 Keywords:  iterator, distance                       |  
-----------------------------------------------------+----------------------
 In functional.hpp at a couple of places, for example:

          static
          BOOST_UBLAS_INLINE
          difference_type distance_i (difference_type k, size_type /*
 size_i */, size_type size_j) {
              return size_j != 0 ? k / size_j : 0;
          }

 k [ / | % ] size_[ i | j ] is used, where k is difference_type (signed),
 size_i|j is size_type (unsigned). This results in promoting k to unsigned,
 and can yield very strange results when k is negative.

 For example, m being a size 2x2 ublas::matrix,
 m.begin1() - m.end1()
 yields 2147483646 instead of -2.

 Putting a static_cast<difference_type>(size_i|j) in functional.hpp
 seems to solve the problem.

-- 
Ticket URL: <https://svn.boost.org/trac/boost/ticket/6072>
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