BitSet.hh

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#ifndef COSA_BITSET_HH
#define COSA_BITSET_HH

#include "Cosa/Types.h"
#include "Cosa/IOStream.hh"

template<uint16_t N>
class BitSet {
public:
  BitSet()
    __attribute__((always_inline))
  {
    empty();
  }

  uint16_t members() const
  {
    return (N);
  }

  const uint8_t* bits() const
  {
    return (m_set);
  }

  void empty()
    __attribute__((always_inline))
  {
    memset(m_set, 0, sizeof(m_set));
  }

  bool is_empty() const
  {
    for (uint16_t i = 0; i < sizeof(m_set); i++)
      if (m_set[i] != 0) return (false);
    return (true);
  }

  bool operator[](uint16_t ix) const
  {
    return ((ix < N) ? ((m_set[ix / CHARBITS] & _BV(ix & MASK)) != 0) : false);
  }

  void operator+=(uint16_t ix)
  {
    if (ix < N) m_set[ix / CHARBITS] |= _BV(ix & MASK);
  }

  void operator-=(uint16_t ix)
  {
    if (ix < N) m_set[ix / CHARBITS] &= ~_BV(ix & MASK);
  }

  void operator=(BitSet& rhs)
  {
    if (UNLIKELY(rhs.members() != N)) return;
    for (uint16_t i = 0; i < sizeof(m_set); i++)
      m_set[i] = rhs.m_set[i];
  }

  void operator+=(BitSet& rhs)
  {
    if (UNLIKELY(rhs.members() != N)) return;
    for (uint16_t i = 0; i < sizeof(m_set); i++)
      m_set[i] |= rhs.m_set[i];
  }

  void operator-=(BitSet& rhs)
  {
    if (UNLIKELY(rhs.members() != N)) return;
    for (uint16_t i = 0; i < sizeof(m_set); i++)
      m_set[i] &= ~rhs.m_set[i];
  }

  bool operator==(BitSet& rhs)
  {
    if (UNLIKELY(rhs.members() != N)) return (false);
    return (memcmp(m_set, rhs.m_set, sizeof(m_set)) == 0);
  }

  friend IOStream& operator<<(IOStream& outs, BitSet& rhs)
  {
    for (uint16_t i = 0; i < N; i++)
      outs << ((rhs.m_set[i / CHARBITS] & _BV(i & MASK)) != 0);
    return (outs);
  }

private:
  static const uint8_t MASK = (CHARBITS - 1);

  static const size_t SET_MAX = (N + (CHARBITS/2)) / CHARBITS;

  uint8_t m_set[SET_MAX];
};
#endif