BitSet.hpp

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/* Handy format-portable template class for bit sets                          */
/*                                                                            */
/******************************************************************************/
 
#ifndef BitSet_Included
#define BitSet_Included
 
/**
 * This is a replacement for the std::bitset class that is more
 * portable. For classes that are saved via rexxc compilation
 * that use FlagSets, the different compiler implementations of
 * the bitset class so not interoperate well. This ensures we
 * have a single data format for saved bitsets across all of the
 * interpreters.
 *
 * This is also simpler than the std bitset, limited to just 32
 * bits in the set and only implementing the operations required
 * by the interpreter.
 */
template<size_t TMaxBits> class BitSet
{   // store fixed-length sequence of Boolean elements
 public:
 
     // default constructor...uses all false values
     BitSet() : bits(0) { }
 
     BitSet& set()
     {
         bits = ~((uint32_t)0);
         return (*this);
     }
 
     inline BitSet& set(size_t pos, bool val = true)
     {
         // belt and braces, don't allow beyond the specified number of bits
         if (pos <= TMaxBits)
         {
             if (val)
             {
                 bits |= (uint32_t)1 << pos;
             }
             else
             {
                 bits &= ~((uint32_t)1 << pos);
             }
         }
 
         return (*this);
     }
 
     BitSet& reset()
     {
         bits = 0;
         return (*this);
     }
 
     inline BitSet& reset(size_t pos)
     {
         return set(pos, false);
     }
 
     BitSet& flip()
     {
         // flip the bits individually so we don't turn on any bits out of range
         for (size_t i = 0; i < TMaxBits; i++)
         {
             flip(i);
         }
         return (*this);
     }
 
     inline BitSet& flip(size_t pos)
     {
         // belt and braces, don't allow beyond the specified number of bits
         if (pos <= TMaxBits)
         {
             bits ^= (uint32_t)1 << pos;
         }
         return (*this);
     }
 
     inline bool test(size_t pos) const
     {
         // belt and braces, don't allow beyond the specified number of bits
         if (pos <= TMaxBits)
         {
             return (bits & ((uint32_t)1 << pos)) != 0;
         }
         else
         {
             return false;
         }
     }
 
     bool any() const
     {
         return bits != 0;
     }
 
     bool none() const
     {
         return bits == 0;
     }
 
     bool all() const
     {
         return count() == TMaxBits;
     }
 
 
 private:
     size_t count() const
     {
         size_t c = 0;
         for (size_t i = 0; i < TMaxBits; i++)
         {
             if (test(i))
             {
                 c++;
             }
         }
         return c;
     }
 
 
 
    uint32_t bits;    // the bits in our bitset
};
 
 
#endif