A bitset index converter to convert mask flag values to their corresponding index in a std::bitset

BitIndexConverter.hpp

/*
 * BitIndexConverter.hpp
 *
 *  Created on: Dec 14, 2013
 *      Author: user
 */

#ifndef BITINDEXCONVERTER_HPP_
#define BITINDEXCONVERTER_HPP_

#include <stdint.h>
#include <limits.h>
#include <bitset>

template<typename BitFieldType, BitFieldType BitValue, int8_t CurIndex>
struct BitIndexSelector;

template<typename BitFieldType, BitFieldType BitValue, int8_t CurIndex>
struct BitIndexSelector
{
    static const int8_t ResultIndex =
            ((CurIndex != -1) &&
             (((((BitFieldType)1) << CurIndex) & BitValue) > 0)
            ? CurIndex
            : BitIndexSelector
                <BitFieldType
                ,BitValue
                ,CurIndex - 1>::ResultIndex);

};

template<typename BitFieldType, BitFieldType BitValue>
struct BitIndexSelector<BitFieldType,BitValue,-1>
{
    static const int8_t ResultIndex = -1;
};

template<typename BitFieldType, BitFieldType BitValue = 0>
struct GetBitIndex
{
    static const int8_t Index =
        BitIndexSelector<BitFieldType,BitValue,sizeof(BitFieldType) * sizeof(char) * CHAR_BIT>::ResultIndex;
    typedef std::bitset<sizeof(BitFieldType) * CHAR_BIT> BitsetType;
};

template<typename BitFieldType>
class BitFieldModifier
{
public:
    typedef std::bitset<sizeof(BitFieldType) * CHAR_BIT> BitsetType;

    BitFieldModifier(BitFieldType& bitfield) : bitfield_(bitfield) {}

private:
    BitFieldType& bitfield_;
};
#endif /* BITINDEXCONVERTER_HPP_ */

main.cpp

/*
 * main.cpp
 *
 *  Created on: Dec 14, 2013
 *      Author: user
 */

#include <cstddef>
#include <poll.h>
#include <iostream>

#include "PollEvents.hpp"

int main()
{
   PollEvents ev;
   ev.event(PollEvents::EV_POLLIN,true);
   ev.event(PollEvents::EV_POLLOUT,true);

   std::cout << ev << std::endl;

   std::cout << "POLLIN: " << ev[PollEvents::EV_POLLIN] << std::endl;
   std::cout << "POLLOUT: " << ev[PollEvents::EV_POLLOUT] << std::endl;
   std::cout << "POLLPRI: " << ev[PollEvents::EV_POLLPRI] << std::endl;
}

PollEvents.hpp

/*
 * PollEvents.hpp
 *
 *  Created on: Dec 14, 2013
 *      Author: user
 */

#ifndef POLLEVENTS_HPP_
#define POLLEVENTS_HPP_

#include <bitset>
#include <poll.h>
#include "BitIndexConverter.hpp"

class PollEvents
{
public:
    typedef typename GetBitIndex<short>::BitsetType BitsetType;

    enum Events
    {
        EV_POLLIN = GetBitIndex<short,POLLIN>::Index ,
        EV_POLLOUT = GetBitIndex<short,POLLOUT>::Index ,
        EV_POLLPRI = GetBitIndex<short,POLLPRI>::Index ,
        EV_POLLRDHUP = GetBitIndex<short,POLLRDHUP>::Index ,
        EV_POLLERR = GetBitIndex<short,POLLERR>::Index ,
        EV_POLLHUP = GetBitIndex<short,POLLHUP>::Index ,
    };

    bool operator[](Events key) const
    {
        return event(key);
    }

    void event(Events key, bool value)
    {
        events_[(std::size_t)key] = value;
    }

    bool event(Events key) const
    {
        return events_[(std::size_t)key];
    }

    void dump(std::ostream& os) const
    {
        os << events_ << std::endl;
    }

private:
    BitsetType events_;
};

std::ostream& operator<<(std::ostream& os, const PollEvents& pollEevents)
{
    pollEevents.dump(os);
    return os;
}
#endif /* POLLEVENTS_HPP_ */