// (C) Copyright 2008-2009 SDML (www.sdml.info)
//
// Use, modification and distribution is subject to the Boost Software
// License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
// http://www.boost.org/LICENSE_1_0.txt)

#ifndef SUFFIX_COMPARE_INCLUDED
#define SUFFIX_COMPARE_INCLUDED

#include <algorithm>
#include <functional>
#include <iterator>

namespace gpld
{

/**
 * suffix_compare is a function object that, given the starting index
 * of two suffices in a string or other iterable container, lexicographically
 * compares the suffices beginning at each location and returns
 * true if the first is 'more comparable' than the other.
 *
 * @todo 'unsigned int'
 */
template <typename T,
          typename Comp = std::less<typename std::iterator_traits<T>::value_type> >
class suffix_compare
{
public:
    suffix_compare(T const& end);
    bool operator()(T const& a, T const& b);

private:
    /** This object cannot be default constructed. */
    suffix_compare();

    /** The end of the range we're comparing. */
    T const& _end;

    /** An instance of the comparison function. */
    Comp _comp;
};

/**
 * The constructor takes a beginning and ending iterator.
 */
template <typename T, typename Comp>
suffix_compare<T, Comp>::suffix_compare(T const& end)
    : _end(end), _comp()
{ }

/**
 * This function performs a lexicographical comparison between
 * the suffix starting at 'a' and the suffix starting at 'b,'
 * and returns true if the suffix starting at 'a' is more
 * comparable.
 */
template <typename T, typename Comp>
bool suffix_compare<T, Comp>::operator()(T const& a, T const& b)
{
    return std::lexicographical_compare(a, _end, b, _end, _comp);
}

};      // end of GPLD namespace

#endif