compare.h

/*
 *  $Id$
 *  Comparator class interface
 *
 *  This file is part of OTAWA
 *  Copyright (c) 2008, IRIT UPS.
 *
 *  OTAWA 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.
 *
 *  OTAWA 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 OTAWA; if not, write to the Free Software
 *  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 */
#ifndef ELM_COMPARATOR_H_
#define ELM_COMPARATOR_H_

#include <elm/string.h>
#include <elm/type_info.h>
#include <elm/util/Pair.h>
#include <elm/util/Equiv.h>

namespace elm {

// Comparator class
template <class T>
class Comparator {
public:
    static inline int compare(const T& v1, const T& v2)
        { if(v1 == v2) return 0; else if(v1 > v2) return 1; else return -1; }
    int doCompare(const T& v1, const T& v2) const { return compare(v1, v2); }
};

// DelegateComparator class
template <class T, class C>
class DelegateComparator {
public:
    static inline int compare(const T& v1, const T& v2) { return C::compare(v1, v2); }
    inline int doCompare(const T& v1, const T& v2) const { return compare(v1, v2); }
};

// CompareComparator class
template <class T>
class CompareComparator {
public:
    static inline int compare(const T& v1, const T& v2) { return v1.compare(v2); }
};
template <> class Comparator<cstring>: public CompareComparator<cstring> { };
template <> class Comparator<string>: public CompareComparator<string> { };


// AssocComparator class
template <class K, class T, class C = Comparator<K> >
class AssocComparator {
public:
    typedef Pair<K, T> pair_t;
    static inline int compare(const pair_t& v1, const pair_t& v2)
        { return C::compare(v1.fst, v2. fst); }
};
template <class K, class T> class Comparator<Pair<K, T> >
    : public AssocComparator<K, T> { };


// ReverseComparator class
template <class T, class C>
class ReverseComparator {
public:
    static inline int compare(const T& v1, const T& v2)
        { return -C::compare(v1, v2); }
};


// CompareEquiv class
template <class T, class C = Comparator<T> >
class CompareEquiv {
public:
    static inline bool equals(const T& v1, const T& v2)
        { return C::compare(v1, v2) == 0; }
};


// Useful inlines
template <class T> inline const T& min(const T& x, const T& y)
    { if(Comparator<T>::compare(x, y) >= 0) return y; else return x; }
template <class T> inline const T& max(const T& x, const T& y)
    { if(Comparator<T>::compare(x, y) >= 0) return x; else return y; }

} // elm

#endif /* ELM_COMPARATOR_H_ */