bug in flags checking in map.h?

[dpinol]

Hi,
I get this error running cppcheck in gmapping.

/home/dani/svn/stacks/pal_navigation_slam/pal_gmapping/build/gmapping_export/grid/map.h:193: style: Suspicious expression. Boolean result is used in bitwise operation. The operator '!'and the comparison operators have higher precedence than bitwise operators. It is recommended that the expression is clarified with parentheses. [cppcheck: clarifyCondition]
/home/dani/svn/stacks/pal_navigation_slam/pal_gmapping/build/gmapping_export/grid/map.h:206: style: Suspicious expression. Boolean result is used in bitwise operation. The operator '!'and the comparison operators have higher precedence than bitwise operators. It is recommended that the expression is clarified with parentheses. [cppcheck: clarifyCondition]

Effectively, running the code below produces this, which does not much sense, unless the flags are not bit flags, in which case imho it does not make much sense to use binary operator &

0: Outside. not inside. Allocated. 
1: Outside. inside. Allocated. 
2: Outside. inside. Allocated. 
3: Outside. inside. Allocated. 

If the checks are changed to " if (! (s&Outside))" it makes a bit more sense, but not for Outside values.

0: not Outside. not inside. not Allocated. 
1: not Outside. inside. not Allocated. 
2: not Outside. not inside. Allocated. 
3: not Outside. inside. Allocated.

thanks

#include <iostream>

int main(int argc, char *argv[])
{
  enum AccessibilityState{Outside=0x0, Inside=0x1, Allocated=0x2};

  int state[] =  { Outside, Inside, Allocated, Inside|Allocated};
  for (int i=0; i < sizeof(state) /sizeof(state[0]); i++)
  {
    int s = state[i];
    std::cout << s << ": ";

    if (! s&Outside)
      std::cout << "not Outside. ";
    else
      std::cout << "Outside. ";

    if (! s&Inside)
      std::cout << "not inside. ";
    else
      std::cout << "inside. ";

    if (! s&Allocated)
      std::cout << "not Allocated. ";
    else
      std::cout << "Allocated. ";
    std::cout << std::endl;
  }

[vrabaud]

Super late on that one but: I agree with your remarks but I believe that the code should be if (! (s&Inside)).
First, well, that's how it reads. Then, it actually does not change anything as you proved: if s is Inside, the two expressions give the same results: (! (1&1))=(!1)=0 and ((!1)&1)=(0&1)=0. If the conditions were true at the lines cppcheck mentions, well, the code would simply stop. If that never happens, that means the check for Inside is done before the function call or does not need to be,
So I'll make the change to get cppcheck quite.

I also agree with you too that it does not make sense for Outside and Allocated but those are not in map.h