/shared/development/google_code/rssoft/library/lib/GF2_Element.h

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/*
     Copyright 2013 Edouard Griffiths <f4exb at free dot fr>

     This file is part of RSSoft. A Reed-Solomon Soft Decoding library

     This program is free software; you can redistribute it and/or modify
     it under the terms of the GNU General Public License as published by
     the Free Software Foundation; either version 2 of the License, or
     (at your option) any later version.

     This program is distributed in the hope that it will be useful,
     but WITHOUT ANY WARRANTY; without even the implied warranty of
     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
     GNU General Public License for more details.

     You should have received a copy of the GNU General Public License
     along with this program; if not, write to the Free Software
     Foundation, Inc., 51 Franklin Street, Boston, MA  02110-1301  USA

         Original from Arash Partow (see original copytight notice).
         Modified and included in RSSoft in gf sub-namespace.

         Element in Galois Field GF(2) class

*/
#ifndef __GF2_ELEMENT_H__
#define __GF2_ELEMENT_H__

#include "GF_Exception.h"
#include <iostream>

namespace rssoft
{
namespace gf
{
typedef unsigned char GF2_Symbol; 

class GF2_Element
{

public:

        GF2_Element(GF2_Symbol v = 0);
        GF2_Element(const GF2_Element& gfe);
        ~GF2_Element()
        {
        }

        inline unsigned int uint_value() const
        {
                return (unsigned int) bin_value;
        }

        inline GF2_Element& operator=(const GF2_Element& gfe)
        {
                if (this != &gfe)
                {
                        bin_value = gfe.bin_value;
                }

                return *this;
        }

        inline GF2_Element& operator=(const GF2_Symbol& v)
        {
                bin_value = (v ? 1 : 0);
                return *this;
        }

        inline GF2_Element& operator+=(const GF2_Element& gfe)
        {
                bin_value ^= gfe.bin_value;
                return *this;
        }

        inline GF2_Element& operator+=(const GF2_Symbol& v)
        {
                bin_value ^= (v ? 1 : 0);
                return *this;
        }

        inline GF2_Element& operator-=(const GF2_Element& gfe)
        {
                *this += gfe;
                return *this;
        }

        inline GF2_Element& operator-=(const GF2_Symbol& v)
        {
                *this += (v ? 1 : 0);
                return *this;
        }

        inline GF2_Element& operator*=(const GF2_Element& gfe)
        {
                bin_value *= gfe.bin_value;
                return *this;
        }

        inline GF2_Element& operator*=(const GF2_Symbol& v)
        {
                bin_value *= (v ? 1 : 0);
                return *this;
        }

        inline GF2_Element& operator/=(const GF2_Element& gfe)
        {
                if (gfe.bin_value == 0)
                {
                        throw GF_Exception("Division by zero");
                }

                return *this;
        }

        inline GF2_Element& operator/=(const GF2_Symbol& v)
        {
                if (!v)
                {
                        throw GF_Exception("Division by zero");
                }

                return *this;
        }

        inline GF2_Element& operator^=(const int& n)
        {
                return *this;
        }

        inline bool operator==(const GF2_Element& gfe) const
        {
                return (bin_value == gfe.bin_value);
        }

        inline bool operator==(const GF2_Symbol& v) const
        {
                return (bin_value == (v ? 1 : 0));
        }

        inline bool operator!=(const GF2_Element& gfe) const
        {
                return (bin_value != gfe.bin_value);
        }

        inline bool operator!=(const GF2_Symbol& v) const
        {
                return (bin_value != (v ? 1 : 0));
        }

        inline bool operator<(const GF2_Element& gfe)
        {
                return (bin_value < gfe.bin_value);
        }

        inline bool operator<(const GF2_Symbol& v)
        {
                return (bin_value < (v ? 1 : 0));
        }

        inline bool operator>(const GF2_Element& gfe)
        {
                return (bin_value > gfe.bin_value);
        }

        inline bool operator>(const GF2_Symbol& v)
        {
                return (bin_value > (v ? 1 : 0));
        }

        friend std::ostream& operator <<(std::ostream& os,
                        const GF2_Element& gfe);

private:
        unsigned char bin_value; 
};

GF2_Element operator +(const GF2_Element& a, const GF2_Element& b);
GF2_Element operator -(const GF2_Element& a, const GF2_Element& b);
GF2_Element operator *(const GF2_Element& a, const GF2_Element& b);
GF2_Element operator *(const GF2_Element& a, const GF2_Symbol& b);
GF2_Element operator *(const GF2_Symbol& a, const GF2_Element& b);
GF2_Element operator /(const GF2_Element& a, const GF2_Element& b);
GF2_Element operator ^(const GF2_Element& a, const int& b);

} // namespacegf
} // namespace rssoft

#endif // __GF2_ELEMENT_H__