bitmask.h

// Description: Bit masks
// Documentation: bit_tricks.txt

#ifndef PASTELSYS_BITMASK_H
#define PASTELSYS_BITMASK_H

#include "pastel/sys/integer/finite_integer_concept.h"

namespace Pastel
{

    //! Returns an integer with a single bit set.
    /*!
   Preconditions:
   bit >= 0

   returns:
   An integer in whose bit-representation the
   'bit' bit is one, while the other bits are zero.
   In other words, mod(2^bit, 2^n), where n is the
   number of bits in the integer.
   */
    template <
        typename Finite_Integer,
        Requires<
            Models<Finite_Integer, Finite_Integer_Concept>
        > = 0
    >
    Finite_Integer singleBitMask(integer bit);

    //! Returns an integer with lower bits set.
    /*!
   Preconditions:
   endBit >= 0

   returns:
   An integer in whose bit-representation the
   bits in the range [0, endBit) are one, 
   while the other bits are zero. In other words,
   mod(2^endBit - 1, 2^n), where n is the number 
   of bits.
   */
    template <
        typename Finite_Integer,
        Requires<
            Models<Finite_Integer, Finite_Integer_Concept>
        > = 0
    >
    Finite_Integer bitMask(integer endBit);

    //! Returns an interval of bits set.
    /*!
   Preconditions:
   0 <= beginBit <= endBit

   returns:
   An integer in whose bit-representation the
   bits in the range [beginBit, endBit) are one, 
   while the other bits are zero. In other words,
   mod(2^endBit - 2^beginBit, 2^n),
   where n is the number of bits.
   */
    template <
        typename Finite_Integer,
        Requires<
            Models<Finite_Integer, Finite_Integer_Concept>
        > = 0
    >
    Finite_Integer bitMask(integer beginBit, integer endBit);

}

#include "pastel/sys/bit/bitmask.hpp"

#endif