text: //////////////////////////////////////////////////////////////////////////////
  //
  // (C) Copyright Ion Gaztanaga 2014-2014.
  //
  // Distributed under 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)
  //
  // See http://www.boost.org/libs/intrusive for documentation.
  //
  //////////////////////////////////////////////////////////////////////////////
  
  #ifndef BOOST_INTRUSIVE_DETAIL_ALGORITHM_HPP
  #define BOOST_INTRUSIVE_DETAIL_ALGORITHM_HPP
  
  #ifndef BOOST_CONFIG_HPP
  #  include <boost/config.hpp>
  #endif
  
  #if defined(BOOST_HAS_PRAGMA_ONCE)
  #  pragma once
  #endif
  
  namespace boost {
  namespace intrusive {
  
  struct algo_pred_equal
  {
     template<class T>
     bool operator()(const T &x, const T &y) const
     {  return x == y;  }
  };
  
  struct algo_pred_less
  {
     template<class T>
     bool operator()(const T &x, const T &y) const
     {  return x < y;  }
  };
  
  template<class InputIt1, class InputIt2, class BinaryPredicate>
  bool algo_equal(InputIt1 first1, InputIt1 last1, InputIt2 first2, BinaryPredicate p)
  {
      for (; first1 != last1; ++first1, ++first2) {
          if (!p(*first1, *first2)) {
              return false;
          }
      }
      return true;
  }
  
  template<class InputIt1, class InputIt2>
  bool algo_equal(InputIt1 first1, InputIt1 last1, InputIt2 first2)
  {  return (algo_equal)(first1, last1, first2, algo_pred_equal());  }
  
  template<class InputIt1, class InputIt2, class BinaryPredicate>
  bool algo_equal(InputIt1 first1, InputIt1 last1, InputIt2 first2, InputIt2 last2, BinaryPredicate pred)
  {
      for (; first1 != last1 && first2 != last2; ++first1, ++first2)
          if (!pred(*first1, *first2))
              return false;
      return first1 == last1 && first2 == last2;
  }
  
  template<class InputIt1, class InputIt2>
  bool algo_equal(InputIt1 first1, InputIt1 last1, InputIt2 first2, InputIt2 last2)
  {  return (algo_equal)(first1, last1, first2, last2, algo_pred_equal());  }
  
  template <class InputIterator1, class InputIterator2, class BinaryPredicate>
    bool algo_lexicographical_compare (InputIterator1 first1, InputIterator1 last1,
                                       InputIterator2 first2, InputIterator2 last2,
                                       BinaryPredicate pred)
  {
     while (first1 != last1){
        if (first2 == last2 || *first2 < *first1) return false;
        else if (pred(*first1, *first2)) return true;
        ++first1; ++first2;
     }
     return (first2 != last2);
  }
  
  template <class InputIterator1, class InputIterator2>
    bool algo_lexicographical_compare (InputIterator1 first1, InputIterator1 last1,
                                       InputIterator2 first2, InputIterator2 last2)
  {  return (algo_lexicographical_compare)(first1, last1, first2, last2, algo_pred_less());  }
  
  }  //namespace intrusive {
  }  //namespace boost {
  
  #endif   //#ifndef BOOST_INTRUSIVE_DETAIL_ALGORITHM_HPP
  