base_sorter.h

// ---------------------------------------------------------------------------
//
//  This file is part of PermLib.
//
// Copyright (c) 2009-2011 Thomas Rehn <thomas@carmen76.de>
// All rights reserved.
// 
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions
// are met:
// 1. Redistributions of source code must retain the above copyright
//    notice, this list of conditions and the following disclaimer.
// 2. Redistributions in binary form must reproduce the above copyright
//    notice, this list of conditions and the following disclaimer in the
//    documentation and/or other materials provided with the distribution.
// 3. The name of the author may not be used to endorse or promote products
//    derived from this software without specific prior written permission.
// 
// THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
// IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
// OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
// IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
// INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
// NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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// THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
//
// ---------------------------------------------------------------------------
 
 
#ifndef BASESORTER_H
#define BASESORTER_H
 
#include <boost/utility.hpp>
 
namespace permlib {

template<class ORDER>
class OrderedSorter {
public:
        bool operator() (unsigned long a, unsigned long b) const {
                BOOST_ASSERT(a < m_size && b < m_size);
                return m_order[a] < m_order[b];
        }
protected:

        explicit OrderedSorter(unsigned int size) 
                : m_size(size),
                // initialize m_size elements with value m_size
                m_order(m_size, m_size)
        {}
        
        explicit OrderedSorter(ORDER order) 
                : m_size(order.size()), m_order(order)
        {}
        
        unsigned int m_size;
        ORDER m_order;
};


class BaseSorter : public OrderedSorter<std::vector<unsigned long> > {
public:

        template <class InputIterator>
        BaseSorter(unsigned int size, InputIterator begin, InputIterator end) 
                : OrderedSorter<std::vector<unsigned long> >(size)
        {
                fillOrder(begin, end, m_order);
        }
        

        template <class InputIterator>
        static void fillOrder(InputIterator begin, InputIterator end, std::vector<unsigned long>& order) {
                InputIterator it;
                unsigned int i = 0;
                // base elements first
                for (it = begin; it != end; ++it) {
                        order[*it] = ++i;
                }
        }
};
 


class BaseSorterByReference : public OrderedSorter<const std::vector<unsigned long>&> {
public:
        explicit BaseSorterByReference(const std::vector<unsigned long>& order) : OrderedSorter<const std::vector<unsigned long>& >(order)
        { }
        
        template <class InputIterator>
        static std::vector<unsigned long> createOrder(unsigned int size, InputIterator begin, InputIterator end) {
                std::vector<unsigned long> order(size,size);
                BaseSorter::fillOrder(begin, end, order);
                return order;
        }
};
 
}
 
#endif // -- BASESORTER_H