diff --git a/ndnboost/unordered/detail/util.hpp b/ndnboost/unordered/detail/util.hpp
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+
+// Copyright (C) 2003-2004 Jeremy B. Maitin-Shepard.
+// Copyright (C) 2005-2011 Daniel James
+// 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)
+
+#ifndef BOOST_UNORDERED_DETAIL_UTIL_HPP_INCLUDED
+#define BOOST_UNORDERED_DETAIL_UTIL_HPP_INCLUDED
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1020)
+# pragma once
+#endif
+
+#include <ndnboost/type_traits/is_convertible.hpp>
+#include <ndnboost/type_traits/is_empty.hpp>
+#include <ndnboost/iterator/iterator_categories.hpp>
+#include <ndnboost/utility/enable_if.hpp>
+#include <ndnboost/detail/select_type.hpp>
+#include <ndnboost/move/move.hpp>
+#include <ndnboost/preprocessor/seq/size.hpp>
+#include <ndnboost/preprocessor/seq/enum.hpp>
+#include <ndnboost/swap.hpp>
+
+namespace ndnboost { namespace unordered { namespace detail {
+
+    static const float minimum_max_load_factor = 1e-3f;
+    static const std::size_t default_bucket_count = 11;
+    struct move_tag {};
+    struct empty_emplace {};
+
+    ////////////////////////////////////////////////////////////////////////////
+    // iterator SFINAE
+
+    template <typename I>
+    struct is_forward :
+        ndnboost::is_convertible<
+            typename ndnboost::iterator_traversal<I>::type,
+            ndnboost::forward_traversal_tag>
+    {};
+
+    template <typename I, typename ReturnType>
+    struct enable_if_forward :
+        ndnboost::enable_if_c<
+            ndnboost::unordered::detail::is_forward<I>::value,
+            ReturnType>
+    {};
+
+    template <typename I, typename ReturnType>
+    struct disable_if_forward :
+        ndnboost::disable_if_c<
+            ndnboost::unordered::detail::is_forward<I>::value,
+            ReturnType>
+    {};
+
+    ////////////////////////////////////////////////////////////////////////////
+    // primes
+
+#define BOOST_UNORDERED_PRIMES \
+    (17ul)(29ul)(37ul)(53ul)(67ul)(79ul) \
+    (97ul)(131ul)(193ul)(257ul)(389ul)(521ul)(769ul) \
+    (1031ul)(1543ul)(2053ul)(3079ul)(6151ul)(12289ul)(24593ul) \
+    (49157ul)(98317ul)(196613ul)(393241ul)(786433ul) \
+    (1572869ul)(3145739ul)(6291469ul)(12582917ul)(25165843ul) \
+    (50331653ul)(100663319ul)(201326611ul)(402653189ul)(805306457ul) \
+    (1610612741ul)(3221225473ul)(4294967291ul)
+
+    template<class T> struct prime_list_template
+    {
+        static std::size_t const value[];
+
+#if !defined(SUNPRO_CC)
+        static std::ptrdiff_t const length;
+#else
+        static std::ptrdiff_t const length
+            = BOOST_PP_SEQ_SIZE(BOOST_UNORDERED_PRIMES);
+#endif
+    };
+
+    template<class T>
+    std::size_t const prime_list_template<T>::value[] = {
+        BOOST_PP_SEQ_ENUM(BOOST_UNORDERED_PRIMES)
+    };
+
+#if !defined(SUNPRO_CC)
+    template<class T>
+    std::ptrdiff_t const prime_list_template<T>::length
+        = BOOST_PP_SEQ_SIZE(BOOST_UNORDERED_PRIMES);
+#endif
+
+#undef BOOST_UNORDERED_PRIMES
+
+    typedef prime_list_template<std::size_t> prime_list;
+
+    // no throw
+    inline std::size_t next_prime(std::size_t num) {
+        std::size_t const* const prime_list_begin = prime_list::value;
+        std::size_t const* const prime_list_end = prime_list_begin +
+            prime_list::length;
+        std::size_t const* bound =
+            std::lower_bound(prime_list_begin, prime_list_end, num);
+        if(bound == prime_list_end)
+            bound--;
+        return *bound;
+    }
+
+    // no throw
+    inline std::size_t prev_prime(std::size_t num) {
+        std::size_t const* const prime_list_begin = prime_list::value;
+        std::size_t const* const prime_list_end = prime_list_begin +
+            prime_list::length;
+        std::size_t const* bound =
+            std::upper_bound(prime_list_begin,prime_list_end, num);
+        if(bound != prime_list_begin)
+            bound--;
+        return *bound;
+    }
+
+    ////////////////////////////////////////////////////////////////////////////
+    // insert_size/initial_size
+
+#if !defined(BOOST_NO_STD_DISTANCE)
+
+    using ::std::distance;
+
+#else
+
+    template <class ForwardIterator>
+    inline std::size_t distance(ForwardIterator i, ForwardIterator j) {
+        std::size_t x;
+        std::distance(i, j, x);
+        return x;
+    }
+
+#endif
+
+    template <class I>
+    inline typename
+        ndnboost::unordered::detail::enable_if_forward<I, std::size_t>::type
+        insert_size(I i, I j)
+    {
+        return std::distance(i, j);
+    }
+
+    template <class I>
+    inline typename
+        ndnboost::unordered::detail::disable_if_forward<I, std::size_t>::type
+        insert_size(I, I)
+    {
+        return 1;
+    }
+
+    template <class I>
+    inline std::size_t initial_size(I i, I j,
+        std::size_t num_buckets =
+            ndnboost::unordered::detail::default_bucket_count)
+    {
+        // TODO: Why +1?
+        return (std::max)(
+            ndnboost::unordered::detail::insert_size(i, j) + 1,
+            num_buckets);
+    }
+
+    ////////////////////////////////////////////////////////////////////////////
+    // compressed
+
+    template <typename T, int Index>
+    struct compressed_base : private T
+    {
+        compressed_base(T const& x) : T(x) {}
+        compressed_base(T& x, move_tag) : T(ndnboost::move(x)) {}
+
+        T& get() { return *this; }
+        T const& get() const { return *this; }
+    };
+    
+    template <typename T, int Index>
+    struct uncompressed_base
+    {
+        uncompressed_base(T const& x) : value_(x) {}
+        uncompressed_base(T& x, move_tag) : value_(ndnboost::move(x)) {}
+
+        T& get() { return value_; }
+        T const& get() const { return value_; }
+    private:
+        T value_;
+    };
+    
+    template <typename T, int Index>
+    struct generate_base
+      : ndnboost::detail::if_true<
+            ndnboost::is_empty<T>::value
+        >:: BOOST_NESTED_TEMPLATE then<
+            ndnboost::unordered::detail::compressed_base<T, Index>,
+            ndnboost::unordered::detail::uncompressed_base<T, Index>
+        >
+    {};
+    
+    template <typename T1, typename T2>
+    struct compressed
+      : private ndnboost::unordered::detail::generate_base<T1, 1>::type,
+        private ndnboost::unordered::detail::generate_base<T2, 2>::type
+    {
+        typedef typename generate_base<T1, 1>::type base1;
+        typedef typename generate_base<T2, 2>::type base2;
+
+        typedef T1 first_type;
+        typedef T2 second_type;
+        
+        first_type& first() {
+            return static_cast<base1*>(this)->get();
+        }
+
+        first_type const& first() const {
+            return static_cast<base1 const*>(this)->get();
+        }
+
+        second_type& second() {
+            return static_cast<base2*>(this)->get();
+        }
+
+        second_type const& second() const {
+            return static_cast<base2 const*>(this)->get();
+        }
+
+        template <typename First, typename Second>
+        compressed(First const& x1, Second const& x2)
+            : base1(x1), base2(x2) {}
+
+        compressed(compressed const& x)
+            : base1(x.first()), base2(x.second()) {}
+
+        compressed(compressed& x, move_tag m)
+            : base1(x.first(), m), base2(x.second(), m) {}
+
+        void assign(compressed const& x)
+        {
+            first() = x.first();
+            second() = x.second();
+        }
+
+        void move_assign(compressed& x)
+        {
+            first() = ndnboost::move(x.first());
+            second() = ndnboost::move(x.second());
+        }
+        
+        void swap(compressed& x)
+        {
+            ndnboost::swap(first(), x.first());
+            ndnboost::swap(second(), x.second());
+        }
+
+    private:
+        // Prevent assignment just to make use of assign or
+        // move_assign explicit.
+        compressed& operator=(compressed const&);
+    };
+}}}
+
+#endif