expair.h

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/*
 *  GiNaC Copyright (C) 1999-2011 Johannes Gutenberg University Mainz, Germany
 *
 *  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, Fifth Floor, Boston, MA  02110-1301  USA
 */

#ifndef GINAC_EXPAIR_H
#define GINAC_EXPAIR_H

#include "ex.h"
#include "numeric.h"
#include "print.h"

namespace GiNaC {

class expair
{
public:
    expair() : rest(0), coeff(1) { }

    expair(const ex & r, const ex & c) : rest(r), coeff(c)
    {
        GINAC_ASSERT(is_exactly_a<numeric>(coeff));
    }
    
    bool is_equal(const expair & other) const
    {
        return (rest.is_equal(other.rest) && coeff.is_equal(other.coeff));
    }
    
    bool is_less(const expair & other) const 
    {
        int restcmp = rest.compare(other.rest);
        return ((restcmp<0) ||
                (!(restcmp>0) && (coeff.compare(other.coeff)<0)));
    }
    
    int compare(const expair & other) const
    {
        int restcmp = rest.compare(other.rest);
        if (restcmp!=0)
            return restcmp;
        else
            return coeff.compare(other.coeff);
    }
    
    void print(std::ostream & os) const;
    
    bool is_canonical_numeric() const
    {
        GINAC_ASSERT(is_exactly_a<numeric>(coeff));
        return (is_exactly_a<numeric>(rest) && (coeff.is_equal(1)));
    }

    void swap(expair & other)
    {
        rest.swap(other.rest);
        coeff.swap(other.coeff);
    }

    const expair conjugate() const;

    ex rest;    
    ex coeff;   
};

struct expair_is_less : public std::binary_function<expair, expair, bool> {
    bool operator()(const expair &lh, const expair &rh) const { return lh.is_less(rh); }
};

struct expair_rest_is_less : public std::binary_function<expair, expair, bool> {
    bool operator()(const expair &lh, const expair &rh) const { return (lh.rest.compare(rh.rest)<0); }
};

struct expair_swap : public std::binary_function<expair, expair, void> {
    void operator()(expair &lh, expair &rh) const { lh.swap(rh); }
};

inline void swap(expair & e1, expair & e2)
{ e1.swap(e2); }

// This makes STL algorithms use the more efficient swap operation for ex objects
inline void iter_swap(std::vector<expair>::iterator i1, std::vector<expair>::iterator i2)
{ i1->swap(*i2); }

} // namespace GiNaC

#endif // ndef GINAC_EXPAIR_H