// Copyright (C) 2003-2004 Jeremy B. Maitin-Shepard.
// Copyright (C) 2005-2016 Daniel James

#ifndef BOOST_UNORDERED_DETAIL_IMPLEMENTATION_HPP
#define BOOST_UNORDERED_DETAIL_IMPLEMENTATION_HPP

#include <boost/config.hpp>
#if defined(BOOST_HAS_PRAGMA_ONCE)
#pragma once
#endif

#include <boost/throw_exception.hpp>
#include <boost/type_traits/is_convertible.hpp>
#include <boost/type_traits/is_empty.hpp>
#include <boost/iterator/iterator_categories.hpp>
#include <boost/utility/enable_if.hpp>
#include <boost/detail/select_type.hpp>
#include <boost/move/move.hpp>
#include <boost/preprocessor/seq/size.hpp>
#include <boost/preprocessor/seq/enum.hpp>
#include <boost/swap.hpp>
#include <boost/unordered/detail/fwd.hpp>
#include <boost/move/move.hpp>
#include <boost/preprocessor/cat.hpp>
#include <boost/preprocessor/repetition/enum.hpp>
#include <boost/preprocessor/repetition/enum_params.hpp>
#include <boost/preprocessor/repetition/enum_binary_params.hpp>
#include <boost/preprocessor/repetition/repeat_from_to.hpp>
#include <boost/type_traits/is_class.hpp>
#include <boost/type_traits/add_lvalue_reference.hpp>
#include <boost/type_traits/aligned_storage.hpp>
#include <boost/type_traits/alignment_of.hpp>
#include <boost/type_traits/is_nothrow_move_constructible.hpp>
#include <boost/type_traits/is_nothrow_move_assignable.hpp>
#include <boost/tuple/tuple.hpp>
#include <boost/utility/enable_if.hpp>
#include <boost/utility/addressof.hpp>
#include <boost/detail/no_exceptions_support.hpp>
#include <boost/detail/select_type.hpp>
#include <boost/swap.hpp>
#include <boost/assert.hpp>
#include <boost/limits.hpp>
#include <iterator>
#include <utility>
#include <cmath>
#include <stdexcept>

#if !defined(BOOST_NO_CXX11_HDR_TUPLE)
#include <tuple>
#endif

namespace boost { 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 {};

    namespace func {
        template <class T>
        inline void ignore_unused_variable_warning(T const&) {}
    }

    ////////////////////////////////////////////////////////////////////////////
    // iterator SFINAE

    template <typename I>
    struct is_forward :
        boost::is_convertible<
            typename boost::iterator_traversal<I>::type,
            boost::forward_traversal_tag>
    {};

    template <typename I, typename ReturnType>
    struct enable_if_forward :
        boost::enable_if_c<
            boost::unordered::detail::is_forward<I>::value,
            ReturnType>
    {};

    template <typename I, typename ReturnType>
    struct disable_if_forward :
        boost::disable_if_c<
            boost::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

    template <class I>
    inline std::size_t insert_size(I i, I j, typename
        boost::unordered::detail::enable_if_forward<I, void*>::type = 0)
    {
        return static_cast<std::size_t>(std::distance(i, j));
    }

    template <class I>
    inline std::size_t insert_size(I, I, typename
        boost::unordered::detail::disable_if_forward<I, void*>::type = 0)
    {
        return 1;
    }

    template <class I>
    inline std::size_t initial_size(I i, I j,
        std::size_t num_buckets =
            boost::unordered::detail::default_bucket_count)
    {
        // TODO: Why +1?
        return (std::max)(
            boost::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(boost::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_(boost::move(x)) {}

        T& get() { return value_; }
        T const& get() const { return value_; }
    private:
        T value_;
    };

    template <typename T, int Index>
    struct generate_base
      : boost::detail::if_true<
            boost::is_empty<T>::value
        >:: BOOST_NESTED_TEMPLATE then<
            boost::unordered::detail::compressed_base<T, Index>,
            boost::unordered::detail::uncompressed_base<T, Index>
        >
    {};

    template <typename T1, typename T2>
    struct compressed
      : private boost::unordered::detail::generate_base<T1, 1>::type,
        private boost::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() = boost::move(x.first());
            second() = boost::move(x.second());
        }

        void swap(compressed& x)
        {
            boost::swap(first(), x.first());
            boost::swap(second(), x.second());
        }

    private:
        // Prevent assignment just to make use of assign or
        // move_assign explicit.
        compressed& operator=(compressed const&);
    };
}}}

#if defined(BOOST_MSVC)
#pragma warning(push)
#pragma warning(disable:4512) // assignment operator could not be generated.
#pragma warning(disable:4345) // behavior change: an object of POD type
                              // constructed with an initializer of the form ()
                              // will be default-initialized.
#endif

// Maximum number of arguments supported by emplace + 1.
#define BOOST_UNORDERED_EMPLACE_LIMIT 11

namespace boost { namespace unordered { namespace detail {

    ////////////////////////////////////////////////////////////////////////////
    // Bits and pieces for implementing traits

    template <typename T> typename boost::add_lvalue_reference<T>::type make();
    struct choice9 { typedef char (&type)[9]; };
    struct choice8 : choice9 { typedef char (&type)[8]; };
    struct choice7 : choice8 { typedef char (&type)[7]; };
    struct choice6 : choice7 { typedef char (&type)[6]; };
    struct choice5 : choice6 { typedef char (&type)[5]; };
    struct choice4 : choice5 { typedef char (&type)[4]; };
    struct choice3 : choice4 { typedef char (&type)[3]; };
    struct choice2 : choice3 { typedef char (&type)[2]; };
    struct choice1 : choice2 { typedef char (&type)[1]; };
    choice1 choose();

    typedef choice1::type yes_type;
    typedef choice2::type no_type;

    struct private_type
    {
       private_type const &operator,(int) const;
    };

    template <typename T>
    no_type is_private_type(T const&);
    yes_type is_private_type(private_type const&);

    struct convert_from_anything {
        template <typename T>
        convert_from_anything(T const&);
    };

    namespace func {
        // This is a bit nasty, when constructing the individual members
        // of a std::pair, need to cast away 'const'. For modern compilers,
        // should be able to use std::piecewise_construct instead.
        template <typename T> T* const_cast_pointer(T* x) { return x; }
        template <typename T> T* const_cast_pointer(T const* x) {
            return const_cast<T*>(x);
        }
    }

    ////////////////////////////////////////////////////////////////////////////
    // emplace_args
    //
    // Either forwarding variadic arguments, or storing the arguments in
    // emplace_args##n

#if !defined(BOOST_NO_CXX11_VARIADIC_TEMPLATES)

#define BOOST_UNORDERED_EMPLACE_ARGS1(a0) a0
#define BOOST_UNORDERED_EMPLACE_ARGS2(a0, a1) a0, a1
#define BOOST_UNORDERED_EMPLACE_ARGS3(a0, a1, a2) a0, a1, a2

#define BOOST_UNORDERED_EMPLACE_TEMPLATE typename... Args
#define BOOST_UNORDERED_EMPLACE_ARGS BOOST_FWD_REF(Args)... args
#define BOOST_UNORDERED_EMPLACE_FORWARD boost::forward<Args>(args)...

#else

#define BOOST_UNORDERED_EMPLACE_ARGS1 create_emplace_args
#define BOOST_UNORDERED_EMPLACE_ARGS2 create_emplace_args
#define BOOST_UNORDERED_EMPLACE_ARGS3 create_emplace_args

#define BOOST_UNORDERED_EMPLACE_TEMPLATE typename Args
#define BOOST_UNORDERED_EMPLACE_ARGS Args const& args
#define BOOST_UNORDERED_EMPLACE_FORWARD args

#if defined(BOOST_NO_CXX11_RVALUE_REFERENCES)

#define BOOST_UNORDERED_EARGS_MEMBER(z, n, _)                               \
    typedef BOOST_FWD_REF(BOOST_PP_CAT(A, n)) BOOST_PP_CAT(Arg, n);         \
    BOOST_PP_CAT(Arg, n) BOOST_PP_CAT(a, n);

#else

#define BOOST_UNORDERED_EARGS_MEMBER(z, n, _)                               \
    typedef typename boost::add_lvalue_reference<BOOST_PP_CAT(A, n)>::type  \
        BOOST_PP_CAT(Arg, n);                                               \
    BOOST_PP_CAT(Arg, n) BOOST_PP_CAT(a, n);

#endif

template <typename A0>
struct emplace_args1
{
    BOOST_UNORDERED_EARGS_MEMBER(1, 0, _)

    emplace_args1(Arg0 b0) : a0(b0) {}
};

template <typename A0>
inline emplace_args1<A0> create_emplace_args(
        BOOST_FWD_REF(A0) b0)
{
    emplace_args1<A0> e(b0);
    return e;
}

template <typename A0, typename A1>
struct emplace_args2
{
    BOOST_UNORDERED_EARGS_MEMBER(1, 0, _)
    BOOST_UNORDERED_EARGS_MEMBER(1, 1, _)

    emplace_args2(Arg0 b0, Arg1 b1) : a0(b0), a1(b1) {}
};

template <typename A0, typename A1>
inline emplace_args2<A0, A1> create_emplace_args(
        BOOST_FWD_REF(A0) b0,
        BOOST_FWD_REF(A1) b1)
{
    emplace_args2<A0, A1> e(b0, b1);
    return e;
}

template <typename A0, typename A1, typename A2>
struct emplace_args3
{
    BOOST_UNORDERED_EARGS_MEMBER(1, 0, _)
    BOOST_UNORDERED_EARGS_MEMBER(1, 1, _)
    BOOST_UNORDERED_EARGS_MEMBER(1, 2, _)

    emplace_args3(Arg0 b0, Arg1 b1, Arg2 b2) : a0(b0), a1(b1), a2(b2) {}
};

template <typename A0, typename A1, typename A2>
inline emplace_args3<A0, A1, A2> create_emplace_args(
        BOOST_FWD_REF(A0) b0,
        BOOST_FWD_REF(A1) b1,
        BOOST_FWD_REF(A2) b2)
{
    emplace_args3<A0, A1, A2> e(b0, b1, b2);
    return e;
}

#define BOOST_UNORDERED_FWD_PARAM(z, n, a) \
    BOOST_FWD_REF(BOOST_PP_CAT(A, n)) BOOST_PP_CAT(a, n)

#define BOOST_UNORDERED_CALL_FORWARD(z, i, a) \
    boost::forward<BOOST_PP_CAT(A,i)>(BOOST_PP_CAT(a,i))

#define BOOST_UNORDERED_EARGS_INIT(z, n, _)                                 \
BOOST_PP_CAT(a, n)(BOOST_PP_CAT(b, n))

#define BOOST_UNORDERED_EARGS(z, n, _)                                      \
    template <BOOST_PP_ENUM_PARAMS_Z(z, n, typename A)>                     \
    struct BOOST_PP_CAT(emplace_args, n)                                    \
    {                                                                       \
        BOOST_PP_REPEAT_##z(n, BOOST_UNORDERED_EARGS_MEMBER, _)             \
        BOOST_PP_CAT(emplace_args, n) (                                     \
            BOOST_PP_ENUM_BINARY_PARAMS_Z(z, n, Arg, b)                     \
        ) : BOOST_PP_ENUM_##z(n, BOOST_UNORDERED_EARGS_INIT, _)             \
        {}                                                                  \
                                                                            \
    };                                                                      \
                                                                            \
    template <BOOST_PP_ENUM_PARAMS_Z(z, n, typename A)>                     \
    inline BOOST_PP_CAT(emplace_args, n) <                                  \
        BOOST_PP_ENUM_PARAMS_Z(z, n, A)                                     \
    > create_emplace_args(                                                  \
        BOOST_PP_ENUM_##z(n, BOOST_UNORDERED_FWD_PARAM, b)                  \
    )                                                                       \
    {                                                                       \
        BOOST_PP_CAT(emplace_args, n) <                                     \
            BOOST_PP_ENUM_PARAMS_Z(z, n, A)                                 \
        > e(BOOST_PP_ENUM_PARAMS_Z(z, n, b));                               \
        return e;                                                           \
    }

BOOST_PP_REPEAT_FROM_TO(4, BOOST_UNORDERED_EMPLACE_LIMIT, BOOST_UNORDERED_EARGS,
    _)

#undef BOOST_UNORDERED_DEFINE_EMPLACE_ARGS
#undef BOOST_UNORDERED_EARGS_MEMBER
#undef BOOST_UNORDERED_EARGS_INIT

#endif

}}}

////////////////////////////////////////////////////////////////////////////////
//
// Pick which version of allocator_traits to use
//
// 0 = Own partial implementation
// 1 = std::allocator_traits
// 2 = boost::container::allocator_traits

#if !defined(BOOST_UNORDERED_USE_ALLOCATOR_TRAITS)
#   if !defined(BOOST_NO_CXX11_ALLOCATOR)
#       define BOOST_UNORDERED_USE_ALLOCATOR_TRAITS 1
#   elif defined(BOOST_MSVC)
#       if BOOST_MSVC < 1400
            // Use container's allocator_traits for older versions of Visual
            // C++ as I don't test with them.
#           define BOOST_UNORDERED_USE_ALLOCATOR_TRAITS 2
#       endif
#   endif
#endif

#if !defined(BOOST_UNORDERED_USE_ALLOCATOR_TRAITS)
#   define BOOST_UNORDERED_USE_ALLOCATOR_TRAITS 0
#endif

////////////////////////////////////////////////////////////////////////////////
//
// Some utilities for implementing allocator_traits, but useful elsewhere so
// they're always defined.

#if !defined(BOOST_NO_CXX11_HDR_TYPE_TRAITS)
#  include <type_traits>
#endif

namespace boost { namespace unordered { namespace detail {

    ////////////////////////////////////////////////////////////////////////////
    // Integral_constrant, true_type, false_type
    //
    // Uses the standard versions if available.

#if !defined(BOOST_NO_CXX11_HDR_TYPE_TRAITS)

    using std::integral_constant;
    using std::true_type;
    using std::false_type;

#else

    template <typename T, T Value>
    struct integral_constant { enum { value = Value }; };

    typedef boost::unordered::detail::integral_constant<bool, true> true_type;
    typedef boost::unordered::detail::integral_constant<bool, false> false_type;

#endif

    ////////////////////////////////////////////////////////////////////////////
    // Explicitly call a destructor

#if defined(BOOST_MSVC)
#pragma warning(push)
#pragma warning(disable:4100) // unreferenced formal parameter
#endif

    namespace func {
        template <class T>
        inline void destroy(T* x) {
            x->~T();
        }
    }

#if defined(BOOST_MSVC)
#pragma warning(pop)
#endif

    ////////////////////////////////////////////////////////////////////////////
    // Expression test mechanism
    //
    // When SFINAE expressions are available, define
    // BOOST_UNORDERED_HAS_FUNCTION which can check if a function call is
    // supported by a class, otherwise define BOOST_UNORDERED_HAS_MEMBER which
    // can detect if a class has the specified member, but not that it has the
    // correct type, this is good enough for a passable impression of
    // allocator_traits.

#if !defined(BOOST_NO_SFINAE_EXPR)

    template <typename T, long unsigned int> struct expr_test;
    template <typename T> struct expr_test<T, sizeof(char)> : T {};

#   define BOOST_UNORDERED_CHECK_EXPRESSION(count, result, expression)      \
        template <typename U>                                               \
        static typename boost::unordered::detail::expr_test<                \
            BOOST_PP_CAT(choice, result),                                   \
            sizeof(for_expr_test((                                          \
                (expression),                                               \
            0)))>::type test(                                               \
            BOOST_PP_CAT(choice, count))

#   define BOOST_UNORDERED_DEFAULT_EXPRESSION(count, result)                \
        template <typename U>                                               \
        static BOOST_PP_CAT(choice, result)::type test(                     \
            BOOST_PP_CAT(choice, count))

#   define BOOST_UNORDERED_HAS_FUNCTION(name, thing, args, _)               \
    struct BOOST_PP_CAT(has_, name)                                         \
    {                                                                       \
        template <typename U> static char for_expr_test(U const&);          \
        BOOST_UNORDERED_CHECK_EXPRESSION(1, 1,                              \
            boost::unordered::detail::make< thing >().name args);           \
        BOOST_UNORDERED_DEFAULT_EXPRESSION(2, 2);                           \
                                                                            \
        enum { value = sizeof(test<T>(choose())) == sizeof(choice1::type) };\
    }

#else

    template <typename T> struct identity { typedef T type; };

#   define BOOST_UNORDERED_CHECK_MEMBER(count, result, name, member)        \
                                                                            \
    typedef typename boost::unordered::detail::identity<member>::type       \
        BOOST_PP_CAT(check, count);                                         \
                                                                            \
    template <BOOST_PP_CAT(check, count) e>                                 \
    struct BOOST_PP_CAT(test, count) {                                      \
        typedef BOOST_PP_CAT(choice, result) type;                          \
    };                                                                      \
                                                                            \
    template <class U> static typename                                      \
        BOOST_PP_CAT(test, count)<&U::name>::type                           \
        test(BOOST_PP_CAT(choice, count))

#   define BOOST_UNORDERED_DEFAULT_MEMBER(count, result)                    \
    template <class U> static BOOST_PP_CAT(choice, result)::type            \
        test(BOOST_PP_CAT(choice, count))

#   define BOOST_UNORDERED_HAS_MEMBER(name)                                 \
    struct BOOST_PP_CAT(has_, name)                                         \
    {                                                                       \
        struct impl {                                                       \
            struct base_mixin { int name; };                                \
            struct base : public T, public base_mixin {};                   \
                                                                            \
            BOOST_UNORDERED_CHECK_MEMBER(1, 1, name, int base_mixin::*);    \
            BOOST_UNORDERED_DEFAULT_MEMBER(2, 2);                           \
                                                                            \
            enum { value = sizeof(choice2::type) ==                         \
                sizeof(test<base>(choose()))                                \
            };                                                              \
        };                                                                  \
                                                                            \
        enum { value = impl::value };                                       \
    }

#endif

}}}

////////////////////////////////////////////////////////////////////////////////
//
// Allocator traits
//
// First our implementation, then later light wrappers around the alternatives

#if BOOST_UNORDERED_USE_ALLOCATOR_TRAITS == 0

#   include <boost/limits.hpp>
#   include <boost/utility/enable_if.hpp>
#   include <boost/pointer_to_other.hpp>
#   if defined(BOOST_NO_SFINAE_EXPR)
#       include <boost/type_traits/is_same.hpp>
#   endif

#   if !defined(BOOST_NO_CXX11_VARIADIC_TEMPLATES) && \
        !defined(BOOST_NO_SFINAE_EXPR)
#       define BOOST_UNORDERED_DETAIL_FULL_CONSTRUCT 1
#   else
#       define BOOST_UNORDERED_DETAIL_FULL_CONSTRUCT 0
#   endif

namespace boost { namespace unordered { namespace detail {

    template <typename Alloc, typename T>
    struct rebind_alloc;

#if !defined(BOOST_NO_CXX11_VARIADIC_TEMPLATES)

    template <template<typename, typename...> class Alloc,
        typename U, typename T, typename... Args>
    struct rebind_alloc<Alloc<U, Args...>, T>
    {
        typedef Alloc<T, Args...> type;
    };

#else

    template <
        template<typename> class Alloc,
        typename U, typename T>
    struct rebind_alloc<Alloc<U>, T>
    {
        typedef Alloc<T> type;
    };

    template <
        template<typename, typename> class Alloc,
        typename U, typename T,
        typename A0>
    struct rebind_alloc<Alloc<U, A0>, T>
    {
        typedef Alloc<T, A0> type;
    };

    template <
        template<typename, typename, typename> class Alloc,
        typename U, typename T,
        typename A0, typename A1>
    struct rebind_alloc<Alloc<U, A0, A1>, T>
    {
        typedef Alloc<T, A0, A1> type;
    };

#endif

    template <typename Alloc, typename T>
    struct rebind_wrap
    {
        template <typename X>
        static choice1::type test(choice1,
            typename X::BOOST_NESTED_TEMPLATE rebind<T>::other* = 0);
        template <typename X>
        static choice2::type test(choice2, void* = 0);

        enum { value = (1 == sizeof(test<Alloc>(choose()))) };

        struct fallback {
            template <typename U>
            struct rebind {
                typedef typename rebind_alloc<Alloc, T>::type other;
            };
        };

        typedef typename boost::detail::if_true<value>::
            BOOST_NESTED_TEMPLATE then<Alloc, fallback>
            ::type::BOOST_NESTED_TEMPLATE rebind<T>::other type;
    };

#   if defined(BOOST_MSVC) && BOOST_MSVC <= 1400

#       define BOOST_UNORDERED_DEFAULT_TYPE_TMPLT(tname)                    \
    template <typename Tp, typename Default>                                \
    struct default_type_ ## tname {                                         \
                                                                            \
        template <typename X>                                               \
        static choice1::type test(choice1, typename X::tname* = 0);         \
                                                                            \
        template <typename X>                                               \
        static choice2::type test(choice2, void* = 0);                      \
                                                                            \
        struct DefaultWrap { typedef Default tname; };                      \
                                                                            \
        enum { value = (1 == sizeof(test<Tp>(choose()))) };                 \
                                                                            \
        typedef typename boost::detail::if_true<value>::                    \
            BOOST_NESTED_TEMPLATE then<Tp, DefaultWrap>                     \
            ::type::tname type;                                             \
    }

#   else

    template <typename T, typename T2>
    struct sfinae : T2 {};

#       define BOOST_UNORDERED_DEFAULT_TYPE_TMPLT(tname)                    \
    template <typename Tp, typename Default>                                \
    struct default_type_ ## tname {                                         \
                                                                            \
        template <typename X>                                               \
        static typename boost::unordered::detail::sfinae<                   \
                typename X::tname, choice1>::type                           \
            test(choice1);                                                  \
                                                                            \
        template <typename X>                                               \
        static choice2::type test(choice2);                                 \
                                                                            \
        struct DefaultWrap { typedef Default tname; };                      \
                                                                            \
        enum { value = (1 == sizeof(test<Tp>(choose()))) };                 \
                                                                            \
        typedef typename boost::detail::if_true<value>::                    \
            BOOST_NESTED_TEMPLATE then<Tp, DefaultWrap>                     \
            ::type::tname type;                                             \
    }

#   endif

#   define BOOST_UNORDERED_DEFAULT_TYPE(T,tname, arg)                   \
    typename default_type_ ## tname<T, arg>::type

    BOOST_UNORDERED_DEFAULT_TYPE_TMPLT(pointer);
    BOOST_UNORDERED_DEFAULT_TYPE_TMPLT(const_pointer);
    BOOST_UNORDERED_DEFAULT_TYPE_TMPLT(void_pointer);
    BOOST_UNORDERED_DEFAULT_TYPE_TMPLT(const_void_pointer);
    BOOST_UNORDERED_DEFAULT_TYPE_TMPLT(difference_type);
    BOOST_UNORDERED_DEFAULT_TYPE_TMPLT(size_type);
    BOOST_UNORDERED_DEFAULT_TYPE_TMPLT(propagate_on_container_copy_assignment);
    BOOST_UNORDERED_DEFAULT_TYPE_TMPLT(propagate_on_container_move_assignment);
    BOOST_UNORDERED_DEFAULT_TYPE_TMPLT(propagate_on_container_swap);

#   if !defined(BOOST_NO_SFINAE_EXPR)

    template <typename T>
    BOOST_UNORDERED_HAS_FUNCTION(
        select_on_container_copy_construction, U const, (), 0
    );

    template <typename T>
    BOOST_UNORDERED_HAS_FUNCTION(
        max_size, U const, (), 0
    );

#       if !defined(BOOST_NO_CXX11_VARIADIC_TEMPLATES)

    template <typename T, typename ValueType, typename... Args>
    BOOST_UNORDERED_HAS_FUNCTION(
    construct, U, (
        boost::unordered::detail::make<ValueType*>(),
        boost::unordered::detail::make<Args const>()...), 2
    );

#       else

    template <typename T, typename ValueType>
    BOOST_UNORDERED_HAS_FUNCTION(
    construct, U, (
        boost::unordered::detail::make<ValueType*>(),
        boost::unordered::detail::make<ValueType const>()), 2
    );

#       endif

    template <typename T, typename ValueType>
    BOOST_UNORDERED_HAS_FUNCTION(
        destroy, U, (boost::unordered::detail::make<ValueType*>()), 1
    );

#   else

    template <typename T>
    BOOST_UNORDERED_HAS_MEMBER(select_on_container_copy_construction);

    template <typename T>
    BOOST_UNORDERED_HAS_MEMBER(max_size);

    template <typename T, typename ValueType>
    BOOST_UNORDERED_HAS_MEMBER(construct);

    template <typename T, typename ValueType>
    BOOST_UNORDERED_HAS_MEMBER(destroy);

#   endif

    namespace func
    {

    template <typename Alloc>
    inline Alloc call_select_on_container_copy_construction(const Alloc& rhs,
        typename boost::enable_if_c<
            boost::unordered::detail::
            has_select_on_container_copy_construction<Alloc>::value, void*
        >::type = 0)
    {
        return rhs.select_on_container_copy_construction();
    }

    template <typename Alloc>
    inline Alloc call_select_on_container_copy_construction(const Alloc& rhs,
        typename boost::disable_if_c<
            boost::unordered::detail::
            has_select_on_container_copy_construction<Alloc>::value, void*
        >::type = 0)
    {
        return rhs;
    }

    template <typename SizeType, typename Alloc>
    inline SizeType call_max_size(const Alloc& a,
        typename boost::enable_if_c<
            boost::unordered::detail::has_max_size<Alloc>::value, void*
        >::type = 0)
    {
        return a.max_size();
    }

    template <typename SizeType, typename Alloc>
    inline SizeType call_max_size(const Alloc&, typename boost::disable_if_c<
            boost::unordered::detail::has_max_size<Alloc>::value, void*
        >::type = 0)
    {
        return (std::numeric_limits<SizeType>::max)();
    }

    } // namespace func.

    template <typename Alloc>
    struct allocator_traits
    {
        typedef Alloc allocator_type;
        typedef typename Alloc::value_type value_type;

        typedef BOOST_UNORDERED_DEFAULT_TYPE(Alloc, pointer, value_type*)
            pointer;

        template <typename T>
        struct pointer_to_other : boost::pointer_to_other<pointer, T> {};

        typedef BOOST_UNORDERED_DEFAULT_TYPE(Alloc, const_pointer,
            typename pointer_to_other<const value_type>::type)
            const_pointer;

        //typedef BOOST_UNORDERED_DEFAULT_TYPE(Alloc, void_pointer,
        //    typename pointer_to_other<void>::type)
        //    void_pointer;
        //
        //typedef BOOST_UNORDERED_DEFAULT_TYPE(Alloc, const_void_pointer,
        //    typename pointer_to_other<const void>::type)
        //    const_void_pointer;

        typedef BOOST_UNORDERED_DEFAULT_TYPE(Alloc, difference_type,
            std::ptrdiff_t) difference_type;

        typedef BOOST_UNORDERED_DEFAULT_TYPE(Alloc, size_type, std::size_t)
            size_type;

#if !defined(BOOST_NO_CXX11_TEMPLATE_ALIASES)
        template <typename T>
        using rebind_alloc = typename rebind_wrap<Alloc, T>::type;

        template <typename T>
        using rebind_traits =
            boost::unordered::detail::allocator_traits<rebind_alloc<T> >;
#endif

        static pointer allocate(Alloc& a, size_type n)
            { return a.allocate(n); }

        // I never use this, so I'll just comment it out for now.
        //
        //static pointer allocate(Alloc& a, size_type n,
        //        const_void_pointer hint)
        //    { return DEFAULT_FUNC(allocate, pointer)(a, n, hint); }

        static void deallocate(Alloc& a, pointer p, size_type n)
            { a.deallocate(p, n); }

    public:

#   if BOOST_UNORDERED_DETAIL_FULL_CONSTRUCT

        template <typename T, typename... Args>
        static typename boost::enable_if_c<
                boost::unordered::detail::has_construct<Alloc, T, Args...>
                ::value>::type
            construct(Alloc& a, T* p, BOOST_FWD_REF(Args)... x)
        {
            a.construct(p, boost::forward<Args>(x)...);
        }

        template <typename T, typename... Args>
        static typename boost::disable_if_c<
                boost::unordered::detail::has_construct<Alloc, T, Args...>
                ::value>::type
            construct(Alloc&, T* p, BOOST_FWD_REF(Args)... x)
        {
            new (static_cast<void*>(p)) T(boost::forward<Args>(x)...);
        }

        template <typename T>
        static typename boost::enable_if_c<
                boost::unordered::detail::has_destroy<Alloc, T>::value>::type
            destroy(Alloc& a, T* p)
        {
            a.destroy(p);
        }

        template <typename T>
        static typename boost::disable_if_c<
                boost::unordered::detail::has_destroy<Alloc, T>::value>::type
            destroy(Alloc&, T* p)
        {
            boost::unordered::detail::func::destroy(p);
        }

#   elif !defined(BOOST_NO_SFINAE_EXPR)

        template <typename T>
        static typename boost::enable_if_c<
                boost::unordered::detail::has_construct<Alloc, T>::value>::type
            construct(Alloc& a, T* p, T const& x)
        {
            a.construct(p, x);
        }

        template <typename T>
        static typename boost::disable_if_c<
                boost::unordered::detail::has_construct<Alloc, T>::value>::type
            construct(Alloc&, T* p, T const& x)
        {
            new (static_cast<void*>(p)) T(x);
        }

        template <typename T>
        static typename boost::enable_if_c<
                boost::unordered::detail::has_destroy<Alloc, T>::value>::type
            destroy(Alloc& a, T* p)
        {
            a.destroy(p);
        }

        template <typename T>
        static typename boost::disable_if_c<
                boost::unordered::detail::has_destroy<Alloc, T>::value>::type
            destroy(Alloc&, T* p)
        {
            boost::unordered::detail::func::destroy(p);
        }

#   else

        // If we don't have SFINAE expressions, only call construct for the
        // copy constructor for the allocator's value_type - as that's
        // the only construct method that old fashioned allocators support.

        template <typename T>
        static void construct(Alloc& a, T* p, T const& x,
            typename boost::enable_if_c<
                    boost::unordered::detail::has_construct<Alloc, T>::value &&
                    boost::is_same<T, value_type>::value,
                    void*>::type = 0)
        {
            a.construct(p, x);
        }

        template <typename T>
        static void construct(Alloc&, T* p, T const& x,
            typename boost::disable_if_c<
                boost::unordered::detail::has_construct<Alloc, T>::value &&
                boost::is_same<T, value_type>::value,
                void*>::type = 0)
        {
            new (static_cast<void*>(p)) T(x);
        }

        template <typename T>
        static void destroy(Alloc& a, T* p,
            typename boost::enable_if_c<
                boost::unordered::detail::has_destroy<Alloc, T>::value &&
                boost::is_same<T, value_type>::value,
                void*>::type = 0)
        {
            a.destroy(p);
        }

        template <typename T>
        static void destroy(Alloc&, T* p,
            typename boost::disable_if_c<
                boost::unordered::detail::has_destroy<Alloc, T>::value &&
                boost::is_same<T, value_type>::value,
                void*>::type = 0)
        {
            boost::unordered::detail::func::destroy(p);
        }

#   endif

        static size_type max_size(const Alloc& a)
        {
            return boost::unordered::detail::func::
                call_max_size<size_type>(a);
        }

        // Allocator propagation on construction

        static Alloc select_on_container_copy_construction(Alloc const& rhs)
        {
            return boost::unordered::detail::func::
                call_select_on_container_copy_construction(rhs);
        }

        // Allocator propagation on assignment and swap.
        // Return true if lhs is modified.
        typedef BOOST_UNORDERED_DEFAULT_TYPE(
            Alloc, propagate_on_container_copy_assignment, false_type)
            propagate_on_container_copy_assignment;
        typedef BOOST_UNORDERED_DEFAULT_TYPE(
            Alloc,propagate_on_container_move_assignment, false_type)
            propagate_on_container_move_assignment;
        typedef BOOST_UNORDERED_DEFAULT_TYPE(
            Alloc,propagate_on_container_swap,false_type)
            propagate_on_container_swap;
    };
}}}

#   undef BOOST_UNORDERED_DEFAULT_TYPE_TMPLT
#   undef BOOST_UNORDERED_DEFAULT_TYPE

////////////////////////////////////////////////////////////////////////////////
//
// std::allocator_traits

#elif BOOST_UNORDERED_USE_ALLOCATOR_TRAITS == 1

#   include <memory>

#   define BOOST_UNORDERED_DETAIL_FULL_CONSTRUCT 1

namespace boost { namespace unordered { namespace detail {

    template <typename Alloc>
    struct allocator_traits : std::allocator_traits<Alloc> {};

    template <typename Alloc, typename T>
    struct rebind_wrap
    {
        typedef typename std::allocator_traits<Alloc>::
            template rebind_alloc<T> type;
    };
}}}

////////////////////////////////////////////////////////////////////////////////
//
// boost::container::allocator_traits

#elif BOOST_UNORDERED_USE_ALLOCATOR_TRAITS == 2

#   include <boost/container/allocator_traits.hpp>

#   define BOOST_UNORDERED_DETAIL_FULL_CONSTRUCT 0

namespace boost { namespace unordered { namespace detail {

    template <typename Alloc>
    struct allocator_traits :
        boost::container::allocator_traits<Alloc> {};

    template <typename Alloc, typename T>
    struct rebind_wrap :
        boost::container::allocator_traits<Alloc>::
            template portable_rebind_alloc<T>
    {};

}}}

#else

#error "Invalid BOOST_UNORDERED_USE_ALLOCATOR_TRAITS value."

#endif


namespace boost { namespace unordered { namespace detail { namespace func {

    ////////////////////////////////////////////////////////////////////////////
    // call_construct

#if !defined(BOOST_NO_CXX11_VARIADIC_TEMPLATES)

#   if BOOST_UNORDERED_DETAIL_FULL_CONSTRUCT

    template <typename Alloc, typename T, typename... Args>
    inline void call_construct(Alloc& alloc, T* address,
        BOOST_FWD_REF(Args)... args)
    {
        boost::unordered::detail::allocator_traits<Alloc>::construct(alloc,
            address, boost::forward<Args>(args)...);
    }

    template <typename Alloc, typename T>
    inline void call_destroy(Alloc& alloc, T* x) {
        boost::unordered::detail::allocator_traits<Alloc>::destroy(alloc, x);
    }


#   else

    template <typename Alloc, typename T, typename... Args>
    inline void call_construct(Alloc&, T* address,
        BOOST_FWD_REF(Args)... args)
    {
        new((void*) address) T(boost::forward<Args>(args)...);
    }

    template <typename Alloc, typename T>
    inline void call_destroy(Alloc&, T* x) {
        boost::unordered::detail::func::destroy(x);
    }


#   endif

#else
    template <typename Alloc, typename T>
    inline void call_construct(Alloc&, T* address)
    {
        new ((void*) address) T();
    }

    template <typename Alloc, typename T, typename A0>
    inline void call_construct(Alloc&, T* address,
        BOOST_FWD_REF(A0) a0)
    {
        new ((void*) address) T(boost::forward<A0>(a0));
    }

    template <typename Alloc, typename T>
    inline void call_destroy(Alloc&, T* x) {
        boost::unordered::detail::func::destroy(x);
    }

#endif

    ////////////////////////////////////////////////////////////////////////////
    // Construct from tuple
    //
    // Used for piecewise construction.

#if !defined(BOOST_NO_CXX11_VARIADIC_TEMPLATES)

#   define BOOST_UNORDERED_CONSTRUCT_FROM_TUPLE(n, namespace_)              \
    template<typename Alloc, typename T>                                    \
    void construct_from_tuple(Alloc& alloc, T* ptr, namespace_ tuple<>)     \
    {                                                                       \
        boost::unordered::detail::func::call_construct(alloc, ptr);         \
    }                                                                       \
                                                                            \
    BOOST_PP_REPEAT_FROM_TO(1, n,                                           \
        BOOST_UNORDERED_CONSTRUCT_FROM_TUPLE_IMPL, namespace_)

#   define BOOST_UNORDERED_CONSTRUCT_FROM_TUPLE_IMPL(z, n, namespace_)      \
    template<typename Alloc, typename T,                                    \
        BOOST_PP_ENUM_PARAMS_Z(z, n, typename A)>                           \
    void construct_from_tuple(Alloc& alloc, T* ptr,                         \
            namespace_ tuple<BOOST_PP_ENUM_PARAMS_Z(z, n, A)> const& x)     \
    {                                                                       \
        boost::unordered::detail::func::call_construct(alloc, ptr,          \
            BOOST_PP_ENUM_##z(n, BOOST_UNORDERED_GET_TUPLE_ARG, namespace_) \
        );                                                                  \
    }

#   define BOOST_UNORDERED_GET_TUPLE_ARG(z, n, namespace_)                  \
    namespace_ get<n>(x)

#elif !defined(__SUNPRO_CC)

#   define BOOST_UNORDERED_CONSTRUCT_FROM_TUPLE(n, namespace_)              \
    template<typename Alloc, typename T>                                    \
    void construct_from_tuple(Alloc&, T* ptr, namespace_ tuple<>)           \
    {                                                                       \
        new ((void*) ptr) T();                                              \
    }                                                                       \
                                                                            \
    BOOST_PP_REPEAT_FROM_TO(1, n,                                           \
        BOOST_UNORDERED_CONSTRUCT_FROM_TUPLE_IMPL, namespace_)

#   define BOOST_UNORDERED_CONSTRUCT_FROM_TUPLE_IMPL(z, n, namespace_)      \
    template<typename Alloc, typename T,                                    \
        BOOST_PP_ENUM_PARAMS_Z(z, n, typename A)>                           \
    void construct_from_tuple(Alloc&, T* ptr,                               \
            namespace_ tuple<BOOST_PP_ENUM_PARAMS_Z(z, n, A)> const& x)     \
    {                                                                       \
        new ((void*) ptr) T(                                                \
            BOOST_PP_ENUM_##z(n, BOOST_UNORDERED_GET_TUPLE_ARG, namespace_) \
        );                                                                  \
    }

#   define BOOST_UNORDERED_GET_TUPLE_ARG(z, n, namespace_)                  \
    namespace_ get<n>(x)

#else

    template <int N> struct length {};

#   define BOOST_UNORDERED_CONSTRUCT_FROM_TUPLE(n, namespace_)              \
    template<typename Alloc, typename T>                                    \
    void construct_from_tuple_impl(                                         \
            boost::unordered::detail::func::length<0>, Alloc&, T* ptr,      \
            namespace_ tuple<>)                                             \
    {                                                                       \
        new ((void*) ptr) T();                                              \
    }                                                                       \
                                                                            \
    BOOST_PP_REPEAT_FROM_TO(1, n,                                           \
        BOOST_UNORDERED_CONSTRUCT_FROM_TUPLE_IMPL, namespace_)

#   define BOOST_UNORDERED_CONSTRUCT_FROM_TUPLE_IMPL(z, n, namespace_)      \
    template<typename Alloc, typename T,                                    \
        BOOST_PP_ENUM_PARAMS_Z(z, n, typename A)>                           \
    void construct_from_tuple_impl(                                         \
            boost::unordered::detail::func::length<n>, Alloc&, T* ptr,      \
            namespace_ tuple<BOOST_PP_ENUM_PARAMS_Z(z, n, A)> const& x)     \
    {                                                                       \
        new ((void*) ptr) T(                                                \
            BOOST_PP_ENUM_##z(n, BOOST_UNORDERED_GET_TUPLE_ARG, namespace_) \
        );                                                                  \
    }

#   define BOOST_UNORDERED_GET_TUPLE_ARG(z, n, namespace_)                  \
    namespace_ get<n>(x)

#endif

BOOST_UNORDERED_CONSTRUCT_FROM_TUPLE(10, boost::)

#if !defined(__SUNPRO_CC) && !defined(BOOST_NO_CXX11_HDR_TUPLE)
   BOOST_UNORDERED_CONSTRUCT_FROM_TUPLE(10, std::)
#endif

#undef BOOST_UNORDERED_CONSTRUCT_FROM_TUPLE
#undef BOOST_UNORDERED_CONSTRUCT_FROM_TUPLE_IMPL
#undef BOOST_UNORDERED_GET_TUPLE_ARG

#if defined(__SUNPRO_CC)

    template <typename Alloc, typename T, typename Tuple>
    void construct_from_tuple(Alloc& alloc, T* ptr, Tuple const& x)
    {
        construct_from_tuple_impl(
            boost::unordered::detail::func::length<
                boost::tuples::length<Tuple>::value>(),
            alloc, ptr, x);
    }

#endif

    ////////////////////////////////////////////////////////////////////////////
    // Trait to check for piecewise construction.

    template <typename A0>
    struct use_piecewise {
        static choice1::type test(choice1,
            boost::unordered::piecewise_construct_t);

        static choice2::type test(choice2, ...);

        enum { value = sizeof(choice1::type) ==
            sizeof(test(choose(), boost::unordered::detail::make<A0>())) };
    };

#if !defined(BOOST_NO_CXX11_VARIADIC_TEMPLATES)

    ////////////////////////////////////////////////////////////////////////////
    // Construct from variadic parameters

    // For the standard pair constructor.

    template <typename Alloc, typename T, typename... Args>
    inline void construct_from_args(Alloc& alloc, T* address,
        BOOST_FWD_REF(Args)... args)
    {
        boost::unordered::detail::func::call_construct(alloc,
            address, boost::forward<Args>(args)...);
    }

    // Special case for piece_construct
    //
    // TODO: When possible, it might be better to use std::pair's
    // constructor for std::piece_construct with std::tuple.

    template <typename Alloc, typename A, typename B,
        typename A0, typename A1, typename A2>
    inline typename enable_if<use_piecewise<A0>, void>::type
        construct_from_args(Alloc& alloc, std::pair<A, B>* address,
            BOOST_FWD_REF(A0), BOOST_FWD_REF(A1) a1, BOOST_FWD_REF(A2) a2)
    {
        boost::unordered::detail::func::construct_from_tuple(alloc,
            boost::unordered::detail::func::const_cast_pointer(
                boost::addressof(address->first)),
            boost::forward<A1>(a1));
        BOOST_TRY {
            boost::unordered::detail::func::construct_from_tuple(alloc,
                boost::unordered::detail::func::const_cast_pointer(
                    boost::addressof(address->second)),
                boost::forward<A2>(a2));
        }
        BOOST_CATCH(...) {
            boost::unordered::detail::func::call_destroy(alloc,
                boost::unordered::detail::func::const_cast_pointer(
                    boost::addressof(address->first)));
            BOOST_RETHROW;
        }
        BOOST_CATCH_END
    }

#else // BOOST_NO_CXX11_VARIADIC_TEMPLATES

    ////////////////////////////////////////////////////////////////////////////
    // Construct from emplace_args

    // Explicitly write out first three overloads for the sake of sane
    // error messages.

    template <typename Alloc, typename T, typename A0>
    inline void construct_from_args(Alloc&, T* address,
            emplace_args1<A0> const& args)
    {
        new((void*) address) T(boost::forward<A0>(args.a0));
    }

    template <typename Alloc, typename T, typename A0, typename A1>
    inline void construct_from_args(Alloc&, T* address,
            emplace_args2<A0, A1> const& args)
    {
        new((void*) address) T(
            boost::forward<A0>(args.a0),
            boost::forward<A1>(args.a1)
        );
    }

    template <typename Alloc, typename T, typename A0, typename A1, typename A2>
    inline void construct_from_args(Alloc&, T* address,
            emplace_args3<A0, A1, A2> const& args)
    {
        new((void*) address) T(
            boost::forward<A0>(args.a0),
            boost::forward<A1>(args.a1),
            boost::forward<A2>(args.a2)
        );
    }

    // Use a macro for the rest.

#define BOOST_UNORDERED_CONSTRUCT_IMPL(z, num_params, _)                    \
    template <                                                              \
        typename Alloc, typename T,                                         \
        BOOST_PP_ENUM_PARAMS_Z(z, num_params, typename A)                   \
    >                                                                       \
    inline void construct_from_args(Alloc&, T* address,                     \
        boost::unordered::detail::BOOST_PP_CAT(emplace_args,num_params) <   \
            BOOST_PP_ENUM_PARAMS_Z(z, num_params, A)                        \
        > const& args)                                                      \
    {                                                                       \
        new((void*) address) T(                                             \
            BOOST_PP_ENUM_##z(num_params, BOOST_UNORDERED_CALL_FORWARD,     \
                args.a));                                                   \
    }

    BOOST_PP_REPEAT_FROM_TO(4, BOOST_UNORDERED_EMPLACE_LIMIT,
        BOOST_UNORDERED_CONSTRUCT_IMPL, _)

#undef BOOST_UNORDERED_CONSTRUCT_IMPL

    // Construct with piece_construct

    template <typename Alloc, typename A, typename B,
        typename A0, typename A1, typename A2>
    inline void construct_from_args(Alloc& alloc, std::pair<A, B>* address,
            boost::unordered::detail::emplace_args3<A0, A1, A2> const& args,
            typename enable_if<use_piecewise<A0>, void*>::type = 0)
    {
        boost::unordered::detail::func::construct_from_tuple(alloc,
            boost::unordered::detail::func::const_cast_pointer(
                boost::addressof(address->first)),
            args.a1);
        BOOST_TRY {
            boost::unordered::detail::func::construct_from_tuple(alloc,
                boost::unordered::detail::func::const_cast_pointer(
                    boost::addressof(address->second)),
                args.a2);
        }
        BOOST_CATCH(...) {
            boost::unordered::detail::func::call_destroy(alloc,
                boost::unordered::detail::func::const_cast_pointer(
                    boost::addressof(address->first)));
            BOOST_RETHROW;
        }
        BOOST_CATCH_END
    }

#endif // BOOST_NO_CXX11_VARIADIC_TEMPLATES

}}}}

namespace boost { namespace unordered { namespace detail {

    ///////////////////////////////////////////////////////////////////
    //
    // Node construction

    template <typename NodeAlloc>
    struct node_constructor
    {
        typedef NodeAlloc node_allocator;
        typedef boost::unordered::detail::allocator_traits<NodeAlloc>
            node_allocator_traits;
        typedef typename node_allocator_traits::value_type node;
        typedef typename node_allocator_traits::pointer node_pointer;
        typedef typename node::value_type value_type;

        node_allocator& alloc_;
        node_pointer node_;
        bool node_constructed_;

        node_constructor(node_allocator& n) :
            alloc_(n),
            node_(),
            node_constructed_(false)
        {
        }

        ~node_constructor();

        void create_node();

        // no throw
        node_pointer release()
        {
            BOOST_ASSERT(node_ && node_constructed_);
            node_pointer p = node_;
            node_ = node_pointer();
            return p;
        }

        void reclaim(node_pointer p) {
            BOOST_ASSERT(!node_);
            node_ = p;
            node_constructed_ = true;
            boost::unordered::detail::func::call_destroy(alloc_,
                node_->value_ptr());
        }

    private:
        node_constructor(node_constructor const&);
        node_constructor& operator=(node_constructor const&);
    };

    template <typename Alloc>
    node_constructor<Alloc>::~node_constructor()
    {
        if (node_) {
            if (node_constructed_) {
                boost::unordered::detail::func::destroy(
                    boost::addressof(*node_));
            }

            node_allocator_traits::deallocate(alloc_, node_, 1);
        }
    }

    template <typename Alloc>
    void node_constructor<Alloc>::create_node()
    {
        BOOST_ASSERT(!node_);
        node_constructed_ = false;

        node_ = node_allocator_traits::allocate(alloc_, 1);

        new ((void*) boost::addressof(*node_)) node();
        node_->init(node_);
        node_constructed_ = true;
    }

    template <typename NodeAlloc>
    struct node_tmp
    {
        typedef boost::unordered::detail::allocator_traits<NodeAlloc>
            node_allocator_traits;
        typedef typename node_allocator_traits::pointer node_pointer;

        NodeAlloc& alloc_;
        node_pointer node_;

        explicit node_tmp(node_pointer n, NodeAlloc& a):
            alloc_(a),
            node_(n)
        {
        }

        ~node_tmp();

        // no throw
        node_pointer release()
        {
            node_pointer p = node_;
            node_ = node_pointer();
            return p;
        }
    };

    template <typename Alloc>
    node_tmp<Alloc>::~node_tmp()
    {
        if (node_) {
            boost::unordered::detail::func::call_destroy(alloc_,
                node_->value_ptr());
            boost::unordered::detail::func::destroy(
                boost::addressof(*node_));
            node_allocator_traits::deallocate(alloc_, node_, 1);
        }
    }
}}}

namespace boost { namespace unordered { namespace detail { namespace func {

    // Some nicer construct_node functions, might try to
    // improve implementation later.

    template <typename Alloc, BOOST_UNORDERED_EMPLACE_TEMPLATE>
    inline typename boost::unordered::detail::allocator_traits<Alloc>::pointer
    construct_node_from_args(Alloc& alloc, BOOST_UNORDERED_EMPLACE_ARGS)
    {
        node_constructor<Alloc> a(alloc);
        a.create_node();
        construct_from_args(alloc, a.node_->value_ptr(),
                BOOST_UNORDERED_EMPLACE_FORWARD);
        return a.release();
    }

    template <typename Alloc, typename U>
    inline typename boost::unordered::detail::allocator_traits<Alloc>::pointer
    construct_node(Alloc& alloc, BOOST_FWD_REF(U) x)
    {
        node_constructor<Alloc> a(alloc);
        a.create_node();
        boost::unordered::detail::func::call_construct(
                alloc, a.node_->value_ptr(), boost::forward<U>(x));
        return a.release();
    }

    // TODO: When possible, it might be better to use std::pair's
    // constructor for std::piece_construct with std::tuple.
    template <typename Alloc, typename Key>
    inline typename boost::unordered::detail::allocator_traits<Alloc>::pointer
    construct_node_pair(Alloc& alloc, BOOST_FWD_REF(Key) k)
    {
        node_constructor<Alloc> a(alloc);
        a.create_node();
        boost::unordered::detail::func::call_construct(alloc,
                boost::unordered::detail::func::const_cast_pointer(
                    boost::addressof(a.node_->value_ptr()->first)),
                boost::forward<Key>(k));
        BOOST_TRY {
            boost::unordered::detail::func::call_construct(alloc,
                    boost::unordered::detail::func::const_cast_pointer(
                        boost::addressof(a.node_->value_ptr()->second)));
        }
        BOOST_CATCH(...) {
            boost::unordered::detail::func::call_destroy(alloc,
                boost::unordered::detail::func::const_cast_pointer(
                    boost::addressof(a.node_->value_ptr()->first)));
            BOOST_RETHROW;
        }
        BOOST_CATCH_END
        return a.release();
    }

    template <typename Alloc, typename Key, typename Mapped>
    inline typename boost::unordered::detail::allocator_traits<Alloc>::pointer
    construct_node_pair(Alloc& alloc, BOOST_FWD_REF(Key) k, BOOST_FWD_REF(Mapped) m)
    {
        node_constructor<Alloc> a(alloc);
        a.create_node();
        boost::unordered::detail::func::call_construct(alloc,
                boost::unordered::detail::func::const_cast_pointer(
                    boost::addressof(a.node_->value_ptr()->first)),
                boost::forward<Key>(k));
        BOOST_TRY {
            boost::unordered::detail::func::call_construct(alloc,
                    boost::unordered::detail::func::const_cast_pointer(
                        boost::addressof(a.node_->value_ptr()->second)),
                    boost::forward<Mapped>(m));
        }
        BOOST_CATCH(...) {
            boost::unordered::detail::func::call_destroy(alloc,
                boost::unordered::detail::func::const_cast_pointer(
                    boost::addressof(a.node_->value_ptr()->first)));
            BOOST_RETHROW;
        }
        BOOST_CATCH_END
        return a.release();
    }
}}}}

#if defined(BOOST_MSVC)
#pragma warning(pop)
#endif

namespace boost { namespace unordered { namespace detail {

    template <typename Types> struct table;
    template <typename NodePointer> struct bucket;
    struct ptr_bucket;
    template <typename Types> struct table_impl;
    template <typename Types> struct grouped_table_impl;

}}}

// The 'iterator_detail' namespace was a misguided attempt at avoiding ADL
// in the detail namespace. It didn't work because the template parameters
// were in detail. I'm not changing it at the moment to be safe. I might
// do in the future if I change the iterator types.
namespace boost { namespace unordered { namespace iterator_detail {

    ////////////////////////////////////////////////////////////////////////////
    // Iterators
    //
    // all no throw

    template <typename Node> struct iterator;
    template <typename Node> struct c_iterator;
    template <typename Node, typename Policy> struct l_iterator;
    template <typename Node, typename Policy>
        struct cl_iterator;

    // Local Iterators
    //
    // all no throw

    template <typename Node, typename Policy>
    struct l_iterator
        : public std::iterator<
            std::forward_iterator_tag,
            typename Node::value_type,
            std::ptrdiff_t,
            typename Node::value_type*,
            typename Node::value_type&>
    {
#if !defined(BOOST_NO_MEMBER_TEMPLATE_FRIENDS)
        template <typename Node2, typename Policy2>
        friend struct boost::unordered::iterator_detail::cl_iterator;
    private:
#endif
        typedef typename Node::node_pointer node_pointer;
        node_pointer ptr_;
        std::size_t bucket_;
        std::size_t bucket_count_;

    public:

        typedef typename Node::value_type value_type;

        l_iterator() BOOST_NOEXCEPT : ptr_() {}

        l_iterator(node_pointer n, std::size_t b, std::size_t c) BOOST_NOEXCEPT
            : ptr_(n), bucket_(b), bucket_count_(c) {}

        value_type& operator*() const {
            return ptr_->value();
        }

        value_type* operator->() const {
            return ptr_->value_ptr();
        }

        l_iterator& operator++() {
            ptr_ = static_cast<node_pointer>(ptr_->next_);
            if (ptr_ && Policy::to_bucket(bucket_count_, ptr_->hash_)
                    != bucket_)
                ptr_ = node_pointer();
            return *this;
        }

        l_iterator operator++(int) {
            l_iterator tmp(*this);
            ++(*this);
            return tmp;
        }

        bool operator==(l_iterator x) const BOOST_NOEXCEPT {
            return ptr_ == x.ptr_;
        }

        bool operator!=(l_iterator x) const BOOST_NOEXCEPT {
            return ptr_ != x.ptr_;
        }
    };

    template <typename Node, typename Policy>
    struct cl_iterator
        : public std::iterator<
            std::forward_iterator_tag,
            typename Node::value_type,
            std::ptrdiff_t,
            typename Node::value_type const*,
            typename Node::value_type const&>
    {
        friend struct boost::unordered::iterator_detail::l_iterator
            <Node, Policy>;
    private:

        typedef typename Node::node_pointer node_pointer;
        node_pointer ptr_;
        std::size_t bucket_;
        std::size_t bucket_count_;

    public:

        typedef typename Node::value_type value_type;

        cl_iterator() BOOST_NOEXCEPT : ptr_() {}

        cl_iterator(node_pointer n, std::size_t b, std::size_t c) BOOST_NOEXCEPT :
            ptr_(n), bucket_(b), bucket_count_(c) {}

        cl_iterator(boost::unordered::iterator_detail::l_iterator<
                Node, Policy> const& x) BOOST_NOEXCEPT :
            ptr_(x.ptr_), bucket_(x.bucket_), bucket_count_(x.bucket_count_)
        {}

        value_type const& operator*() const {
            return ptr_->value();
        }

        value_type const* operator->() const {
            return ptr_->value_ptr();
        }

        cl_iterator& operator++() {
            ptr_ = static_cast<node_pointer>(ptr_->next_);
            if (ptr_ && Policy::to_bucket(bucket_count_, ptr_->hash_)
                    != bucket_)
                ptr_ = node_pointer();
            return *this;
        }

        cl_iterator operator++(int) {
            cl_iterator tmp(*this);
            ++(*this);
            return tmp;
        }

        friend bool operator==(cl_iterator const& x, cl_iterator const& y)
            BOOST_NOEXCEPT
        {
            return x.ptr_ == y.ptr_;
        }

        friend bool operator!=(cl_iterator const& x, cl_iterator const& y)
            BOOST_NOEXCEPT
        {
            return x.ptr_ != y.ptr_;
        }
    };

    template <typename Node>
    struct iterator
        : public std::iterator<
            std::forward_iterator_tag,
            typename Node::value_type,
            std::ptrdiff_t,
            typename Node::value_type*,
            typename Node::value_type&>
    {
#if !defined(BOOST_NO_MEMBER_TEMPLATE_FRIENDS)
        template <typename>
        friend struct boost::unordered::iterator_detail::c_iterator;
        template <typename>
        friend struct boost::unordered::detail::table;
        template <typename>
        friend struct boost::unordered::detail::table_impl;
        template <typename>
        friend struct boost::unordered::detail::grouped_table_impl;
    private:
#endif
        typedef typename Node::node_pointer node_pointer;
        node_pointer node_;

    public:

        typedef typename Node::value_type value_type;

        iterator() BOOST_NOEXCEPT : node_() {}

        explicit iterator(typename Node::link_pointer x) BOOST_NOEXCEPT :
            node_(static_cast<node_pointer>(x)) {}

        value_type& operator*() const {
            return node_->value();
        }

        value_type* operator->() const {
            return node_->value_ptr();
        }

        iterator& operator++() {
            node_ = static_cast<node_pointer>(node_->next_);
            return *this;
        }

        iterator operator++(int) {
            iterator tmp(node_);
            node_ = static_cast<node_pointer>(node_->next_);
            return tmp;
        }

        bool operator==(iterator const& x) const BOOST_NOEXCEPT {
            return node_ == x.node_;
        }

        bool operator!=(iterator const& x) const BOOST_NOEXCEPT {
            return node_ != x.node_;
        }
    };

    template <typename Node>
    struct c_iterator
        : public std::iterator<
            std::forward_iterator_tag,
            typename Node::value_type,
            std::ptrdiff_t,
            typename Node::value_type const*,
            typename Node::value_type const&>
    {
        friend struct boost::unordered::iterator_detail::iterator<Node>;

#if !defined(BOOST_NO_MEMBER_TEMPLATE_FRIENDS)
        template <typename>
        friend struct boost::unordered::detail::table;
        template <typename>
        friend struct boost::unordered::detail::table_impl;
        template <typename>
        friend struct boost::unordered::detail::grouped_table_impl;

    private:
#endif
        typedef typename Node::node_pointer node_pointer;
        typedef boost::unordered::iterator_detail::iterator<Node> n_iterator;
        node_pointer node_;

    public:

        typedef typename Node::value_type value_type;

        c_iterator() BOOST_NOEXCEPT : node_() {}

        explicit c_iterator(typename Node::link_pointer x) BOOST_NOEXCEPT :
            node_(static_cast<node_pointer>(x)) {}

        c_iterator(n_iterator const& x) BOOST_NOEXCEPT : node_(x.node_) {}

        value_type const& operator*() const {
            return node_->value();
        }

        value_type const* operator->() const {
            return node_->value_ptr();
        }

        c_iterator& operator++() {
            node_ = static_cast<node_pointer>(node_->next_);
            return *this;
        }

        c_iterator operator++(int) {
            c_iterator tmp(node_);
            node_ = static_cast<node_pointer>(node_->next_);
            return tmp;
        }

        friend bool operator==(c_iterator const& x, c_iterator const& y)
            BOOST_NOEXCEPT
        {
            return x.node_ == y.node_;
        }

        friend bool operator!=(c_iterator const& x, c_iterator const& y)
            BOOST_NOEXCEPT
        {
            return x.node_ != y.node_;
        }
    };
}}}

namespace boost { namespace unordered { namespace detail {

    ///////////////////////////////////////////////////////////////////
    //
    // Node Holder
    //
    // Temporary store for nodes. Deletes any that aren't used.

    template <typename NodeAlloc>
    struct node_holder
    {
    private:
        typedef NodeAlloc node_allocator;
        typedef boost::unordered::detail::allocator_traits<NodeAlloc>
            node_allocator_traits;
        typedef typename node_allocator_traits::value_type node;
        typedef typename node_allocator_traits::pointer node_pointer;
        typedef typename node::value_type value_type;
        typedef typename node::link_pointer link_pointer;
        typedef boost::unordered::iterator_detail::iterator<node> iterator;

        node_constructor<NodeAlloc> constructor_;
        node_pointer nodes_;

    public:

        template <typename Table>
        explicit node_holder(Table& b) :
            constructor_(b.node_alloc()),
            nodes_()
        {
            if (b.size_) {
                typename Table::link_pointer prev = b.get_previous_start();
                nodes_ = static_cast<node_pointer>(prev->next_);
                prev->next_ = link_pointer();
                b.size_ = 0;
            }
        }

        ~node_holder();

        node_pointer pop_node()
        {
            node_pointer n = nodes_;
            nodes_ = static_cast<node_pointer>(nodes_->next_);
            n->init(n);
            n->next_ = link_pointer();
            return n;
        }

        template <typename T>
        inline node_pointer copy_of(T const& v) {
            if (nodes_) {
                constructor_.reclaim(pop_node());
            }
            else {
                constructor_.create_node();
            }
            boost::unordered::detail::func::call_construct(
                constructor_.alloc_, constructor_.node_->value_ptr(), v);
            return constructor_.release();
        }

        template <typename T>
        inline node_pointer move_copy_of(T& v) {
            if (nodes_) {
                constructor_.reclaim(pop_node());
            }
            else {
                constructor_.create_node();
            }
            boost::unordered::detail::func::call_construct(
                constructor_.alloc_, constructor_.node_->value_ptr(),
                boost::move(v));
            return constructor_.release();
        }

        iterator begin() const
        {
            return iterator(nodes_);
        }
    };

    template <typename Alloc>
    node_holder<Alloc>::~node_holder()
    {
        while (nodes_) {
            node_pointer p = nodes_;
            nodes_ = static_cast<node_pointer>(p->next_);

            boost::unordered::detail::func::call_destroy(constructor_.alloc_,
                p->value_ptr());
            boost::unordered::detail::func::destroy(boost::addressof(*p));
            node_allocator_traits::deallocate(constructor_.alloc_, p, 1);
        }
    }

    ///////////////////////////////////////////////////////////////////
    //
    // Bucket

    template <typename NodePointer>
    struct bucket
    {
        typedef NodePointer link_pointer;
        link_pointer next_;

        bucket() : next_() {}

        link_pointer first_from_start()
        {
            return next_;
        }

        enum { extra_node = true };
    };

    struct ptr_bucket
    {
        typedef ptr_bucket* link_pointer;
        link_pointer next_;

        ptr_bucket() : next_(0) {}

        link_pointer first_from_start()
        {
            return this;
        }

        enum { extra_node = false };
    };

    ///////////////////////////////////////////////////////////////////
    //
    // Hash Policy

    template <typename SizeT>
    struct prime_policy
    {
        template <typename Hash, typename T>
        static inline SizeT apply_hash(Hash const& hf, T const& x) {
            return hf(x);
        }

        static inline SizeT to_bucket(SizeT bucket_count, SizeT hash) {
            return hash % bucket_count;
        }

        static inline SizeT new_bucket_count(SizeT min) {
            return boost::unordered::detail::next_prime(min);
        }

        static inline SizeT prev_bucket_count(SizeT max) {
            return boost::unordered::detail::prev_prime(max);
        }
    };

    template <typename SizeT>
    struct mix64_policy
    {
        template <typename Hash, typename T>
        static inline SizeT apply_hash(Hash const& hf, T const& x) {
            SizeT key = hf(x);
            key = (~key) + (key << 21); // key = (key << 21) - key - 1;
            key = key ^ (key >> 24);
            key = (key + (key << 3)) + (key << 8); // key * 265
            key = key ^ (key >> 14);
            key = (key + (key << 2)) + (key << 4); // key * 21
            key = key ^ (key >> 28);
            key = key + (key << 31);
            return key;
        }

        static inline SizeT to_bucket(SizeT bucket_count, SizeT hash) {
            return hash & (bucket_count - 1);
        }

        static inline SizeT new_bucket_count(SizeT min) {
            if (min <= 4) return 4;
            --min;
            min |= min >> 1;
            min |= min >> 2;
            min |= min >> 4;
            min |= min >> 8;
            min |= min >> 16;
            min |= min >> 32;
            return min + 1;
        }

        static inline SizeT prev_bucket_count(SizeT max) {
            max |= max >> 1;
            max |= max >> 2;
            max |= max >> 4;
            max |= max >> 8;
            max |= max >> 16;
            max |= max >> 32;
            return (max >> 1) + 1;
        }
    };

    template <int digits, int radix>
    struct pick_policy_impl {
        typedef prime_policy<std::size_t> type;
    };

    template <>
    struct pick_policy_impl<64, 2> {
        typedef mix64_policy<std::size_t> type;
    };

    template <typename T>
    struct pick_policy :
        pick_policy_impl<
            std::numeric_limits<std::size_t>::digits,
            std::numeric_limits<std::size_t>::radix> {};

    // While the mix policy is generally faster, the prime policy is a lot
    // faster when a large number consecutive integers are used, because
    // there are no collisions. Since that is probably quite common, use
    // prime policy for integeral types. But not the smaller ones, as they
    // don't have enough unique values for this to be an issue.

    template <>
    struct pick_policy<int> {
        typedef prime_policy<std::size_t> type;
    };

    template <>
    struct pick_policy<unsigned int> {
        typedef prime_policy<std::size_t> type;
    };

    template <>
    struct pick_policy<long> {
        typedef prime_policy<std::size_t> type;
    };

    template <>
    struct pick_policy<unsigned long> {
        typedef prime_policy<std::size_t> type;
    };

    // TODO: Maybe not if std::size_t is smaller than long long.
#if !defined(BOOST_NO_LONG_LONG)
    template <>
    struct pick_policy<boost::long_long_type> {
        typedef prime_policy<std::size_t> type;
    };

    template <>
    struct pick_policy<boost::ulong_long_type> {
        typedef prime_policy<std::size_t> type;
    };
#endif

    ////////////////////////////////////////////////////////////////////////////
    // Functions

    // Assigning and swapping the equality and hash function objects
    // needs strong exception safety. To implement that normally we'd
    // require one of them to be known to not throw and the other to
    // guarantee strong exception safety. Unfortunately they both only
    // have basic exception safety. So to acheive strong exception
    // safety we have storage space for two copies, and assign the new
    // copies to the unused space. Then switch to using that to use
    // them. This is implemented in 'set_hash_functions' which
    // atomically assigns the new function objects in a strongly
    // exception safe manner.

    template <class H, class P, bool NoThrowMoveAssign>
    class set_hash_functions;

    template <class H, class P>
    class functions
    {
    public:
        static const bool nothrow_move_assignable =
                boost::is_nothrow_move_assignable<H>::value &&
                boost::is_nothrow_move_assignable<P>::value;
        static const bool nothrow_move_constructible =
                boost::is_nothrow_move_constructible<H>::value &&
                boost::is_nothrow_move_constructible<P>::value;

    private:
        friend class boost::unordered::detail::set_hash_functions<H, P,
               nothrow_move_assignable>;
        functions& operator=(functions const&);

        typedef compressed<H, P> function_pair;

        typedef typename boost::aligned_storage<
            sizeof(function_pair),
            boost::alignment_of<function_pair>::value>::type aligned_function;

        bool current_; // The currently active functions.
        aligned_function funcs_[2];

        function_pair const& current() const {
            return *static_cast<function_pair const*>(
                static_cast<void const*>(&funcs_[current_]));
        }

        function_pair& current() {
            return *static_cast<function_pair*>(
                static_cast<void*>(&funcs_[current_]));
        }

        void construct(bool which, H const& hf, P const& eq)
        {
            new((void*) &funcs_[which]) function_pair(hf, eq);
        }

        void construct(bool which, function_pair const& f,
                boost::unordered::detail::false_type =
                    boost::unordered::detail::false_type())
        {
            new((void*) &funcs_[which]) function_pair(f);
        }

        void construct(bool which, function_pair& f,
                boost::unordered::detail::true_type)
        {
            new((void*) &funcs_[which]) function_pair(f,
                boost::unordered::detail::move_tag());
        }

        void destroy(bool which)
        {
            boost::unordered::detail::func::destroy((function_pair*)(&funcs_[which]));
        }

    public:

        typedef boost::unordered::detail::set_hash_functions<H, P,
                nothrow_move_assignable> set_hash_functions;

        functions(H const& hf, P const& eq)
            : current_(false)
        {
            construct(current_, hf, eq);
        }

        functions(functions const& bf)
            : current_(false)
        {
            construct(current_, bf.current());
        }

        functions(functions& bf, boost::unordered::detail::move_tag)
            : current_(false)
        {
            construct(current_, bf.current(),
                boost::unordered::detail::integral_constant<bool,
                    nothrow_move_constructible>());
        }

        ~functions() {
            this->destroy(current_);
        }

        H const& hash_function() const {
            return current().first();
        }

        P const& key_eq() const {
            return current().second();
        }
    };

    template <class H, class P>
    class set_hash_functions<H, P, false>
    {
        set_hash_functions(set_hash_functions const&);
        set_hash_functions& operator=(set_hash_functions const&);

        typedef functions<H, P> functions_type;

        functions_type& functions_;
        bool tmp_functions_;

    public:

        set_hash_functions(functions_type& f, H const& h, P const& p)
          : functions_(f),
            tmp_functions_(!f.current_)
        {
            f.construct(tmp_functions_, h, p);
        }

        set_hash_functions(functions_type& f, functions_type const& other)
          : functions_(f),
            tmp_functions_(!f.current_)
        {
            f.construct(tmp_functions_, other.current());
        }

        ~set_hash_functions()
        {
            functions_.destroy(tmp_functions_);
        }

        void commit()
        {
            functions_.current_ = tmp_functions_;
            tmp_functions_ = !tmp_functions_;
        }
    };

    template <class H, class P>
    class set_hash_functions<H, P, true>
    {
        set_hash_functions(set_hash_functions const&);
        set_hash_functions& operator=(set_hash_functions const&);

        typedef functions<H, P> functions_type;

        functions_type& functions_;
        H hash_;
        P pred_;

    public:

        set_hash_functions(functions_type& f, H const& h, P const& p) :
            functions_(f),
            hash_(h),
            pred_(p) {}

        set_hash_functions(functions_type& f, functions_type const& other) :
            functions_(f),
            hash_(other.hash_function()),
            pred_(other.key_eq()) {}

        void commit()
        {
            functions_.current().first() = boost::move(hash_);
            functions_.current().second() = boost::move(pred_);
        }
    };

    ////////////////////////////////////////////////////////////////////////////
    // rvalue parameters when type can't be a BOOST_RV_REF(T) parameter
    // e.g. for int

#if !defined(BOOST_NO_CXX11_RVALUE_REFERENCES)
#   define BOOST_UNORDERED_RV_REF(T) BOOST_RV_REF(T)
#else
    struct please_ignore_this_overload {
        typedef please_ignore_this_overload type;
    };

    template <typename T>
    struct rv_ref_impl {
        typedef BOOST_RV_REF(T) type;
    };

    template <typename T>
    struct rv_ref :
        boost::detail::if_true<
            boost::is_class<T>::value
        >::BOOST_NESTED_TEMPLATE then <
            boost::unordered::detail::rv_ref_impl<T>,
            please_ignore_this_overload
        >::type
    {};

#   define BOOST_UNORDERED_RV_REF(T) \
        typename boost::unordered::detail::rv_ref<T>::type
#endif
}}}

#if defined(BOOST_MSVC)
#pragma warning(push)
#pragma warning(disable:4127) // conditional expression is constant
#endif

namespace boost { namespace unordered { namespace detail {

    ////////////////////////////////////////////////////////////////////////////
    // convert double to std::size_t

    inline std::size_t double_to_size(double f)
    {
        return f >= static_cast<double>(
            (std::numeric_limits<std::size_t>::max)()) ?
            (std::numeric_limits<std::size_t>::max)() :
            static_cast<std::size_t>(f);
    }

    // The space used to store values in a node.

    template <typename ValueType>
    struct value_base
    {
        typedef ValueType value_type;

        typename boost::aligned_storage<
            sizeof(value_type),
            boost::alignment_of<value_type>::value>::type data_;

        value_base() :
            data_()
        {}

        void* address() {
            return this;
        }

        value_type& value() {
            return *(ValueType*) this;
        }

        value_type* value_ptr() {
            return (ValueType*) this;
        }

    private:

        value_base& operator=(value_base const&);
    };

    template <typename Types>
    struct table :
        boost::unordered::detail::functions<
            typename Types::hasher,
            typename Types::key_equal>
    {
    private:
        table(table const&);
        table& operator=(table const&);
    public:
        typedef typename Types::node node;
        typedef typename Types::bucket bucket;
        typedef typename Types::hasher hasher;
        typedef typename Types::key_equal key_equal;
        typedef typename Types::key_type key_type;
        typedef typename Types::extractor extractor;
        typedef typename Types::value_type value_type;
        typedef typename Types::table table_impl;
        typedef typename Types::link_pointer link_pointer;
        typedef typename Types::policy policy;
        typedef typename Types::iterator iterator;
        typedef typename Types::c_iterator c_iterator;
        typedef typename Types::l_iterator l_iterator;
        typedef typename Types::cl_iterator cl_iterator;

        typedef boost::unordered::detail::functions<
            typename Types::hasher,
            typename Types::key_equal> functions;
        typedef typename functions::set_hash_functions set_hash_functions;

        typedef typename Types::allocator allocator;
        typedef typename boost::unordered::detail::
            rebind_wrap<allocator, node>::type node_allocator;
        typedef typename boost::unordered::detail::
            rebind_wrap<allocator, bucket>::type bucket_allocator;
        typedef boost::unordered::detail::allocator_traits<node_allocator>
            node_allocator_traits;
        typedef boost::unordered::detail::allocator_traits<bucket_allocator>
            bucket_allocator_traits;
        typedef typename node_allocator_traits::pointer
            node_pointer;
        typedef typename node_allocator_traits::const_pointer
            const_node_pointer;
        typedef typename bucket_allocator_traits::pointer
            bucket_pointer;
        typedef boost::unordered::detail::node_constructor<node_allocator>
            node_constructor;
        typedef boost::unordered::detail::node_tmp<node_allocator>
            node_tmp;

        ////////////////////////////////////////////////////////////////////////
        // Members

        boost::unordered::detail::compressed<bucket_allocator, node_allocator>
            allocators_;
        std::size_t bucket_count_;
        std::size_t size_;
        float mlf_;
        std::size_t max_load_;
        bucket_pointer buckets_;

        ////////////////////////////////////////////////////////////////////////
        // Node functions

        static inline node_pointer next_node(link_pointer n) {
            return static_cast<node_pointer>(n->next_);
        }

        ////////////////////////////////////////////////////////////////////////
        // Data access

        bucket_allocator const& bucket_alloc() const
        {
            return allocators_.first();
        }

        node_allocator const& node_alloc() const
        {
            return allocators_.second();
        }

        bucket_allocator& bucket_alloc()
        {
            return allocators_.first();
        }

        node_allocator& node_alloc()
        {
            return allocators_.second();
        }

        std::size_t max_bucket_count() const
        {
            // -1 to account for the start bucket.
            return policy::prev_bucket_count(
                bucket_allocator_traits::max_size(bucket_alloc()) - 1);
        }

        bucket_pointer get_bucket(std::size_t bucket_index) const
        {
            BOOST_ASSERT(buckets_);
            return buckets_ + static_cast<std::ptrdiff_t>(bucket_index);
        }

        link_pointer get_previous_start() const
        {
            return get_bucket(bucket_count_)->first_from_start();
        }

        link_pointer get_previous_start(std::size_t bucket_index) const
        {
            return get_bucket(bucket_index)->next_;
        }

        node_pointer begin() const
        {
            return size_ ? next_node(get_previous_start()) : node_pointer();
        }

        node_pointer begin(std::size_t bucket_index) const
        {
            if (!size_) return node_pointer();
            link_pointer prev = get_previous_start(bucket_index);
            return prev ? next_node(prev) : node_pointer();
        }

        std::size_t hash_to_bucket(std::size_t hash_value) const
        {
            return policy::to_bucket(bucket_count_, hash_value);
        }

        float load_factor() const
        {
            BOOST_ASSERT(bucket_count_ != 0);
            return static_cast<float>(size_)
                / static_cast<float>(bucket_count_);
        }

        std::size_t bucket_size(std::size_t index) const
        {
            node_pointer n = begin(index);
            if (!n) return 0;

            std::size_t count = 0;
            while(n && hash_to_bucket(n->hash_) == index)
            {
                ++count;
                n = next_node(n);
            }

            return count;
        }

        ////////////////////////////////////////////////////////////////////////
        // Load methods

        std::size_t max_size() const
        {
            using namespace std;

            // size < mlf_ * count
            return boost::unordered::detail::double_to_size(ceil(
                    static_cast<double>(mlf_) *
                    static_cast<double>(max_bucket_count())
                )) - 1;
        }

        void recalculate_max_load()
        {
            using namespace std;

            // From 6.3.1/13:
            // Only resize when size >= mlf_ * count
            max_load_ = buckets_ ? boost::unordered::detail::double_to_size(ceil(
                    static_cast<double>(mlf_) *
                    static_cast<double>(bucket_count_)
                )) : 0;

        }

        void max_load_factor(float z)
        {
            BOOST_ASSERT(z > 0);
            mlf_ = (std::max)(z, minimum_max_load_factor);
            recalculate_max_load();
        }

        std::size_t min_buckets_for_size(std::size_t size) const
        {
            BOOST_ASSERT(mlf_ >= minimum_max_load_factor);

            using namespace std;

            // From 6.3.1/13:
            // size < mlf_ * count
            // => count > size / mlf_
            //
            // Or from rehash post-condition:
            // count > size / mlf_

            return policy::new_bucket_count(
                boost::unordered::detail::double_to_size(floor(
                    static_cast<double>(size) /
                    static_cast<double>(mlf_)) + 1));
        }

        ////////////////////////////////////////////////////////////////////////
        // Constructors

        table(std::size_t num_buckets,
                hasher const& hf,
                key_equal const& eq,
                node_allocator const& a) :
            functions(hf, eq),
            allocators_(a,a),
            bucket_count_(policy::new_bucket_count(num_buckets)),
            size_(0),
            mlf_(1.0f),
            max_load_(0),
            buckets_()
        {}

        table(table const& x, node_allocator const& a) :
            functions(x),
            allocators_(a,a),
            bucket_count_(x.min_buckets_for_size(x.size_)),
            size_(0),
            mlf_(x.mlf_),
            max_load_(0),
            buckets_()
        {}

        table(table& x, boost::unordered::detail::move_tag m) :
            functions(x, m),
            allocators_(x.allocators_, m),
            bucket_count_(x.bucket_count_),
            size_(x.size_),
            mlf_(x.mlf_),
            max_load_(x.max_load_),
            buckets_(x.buckets_)
        {
            x.buckets_ = bucket_pointer();
            x.size_ = 0;
            x.max_load_ = 0;
        }

        table(table& x, node_allocator const& a,
                boost::unordered::detail::move_tag m) :
            functions(x, m),
            allocators_(a, a),
            bucket_count_(x.bucket_count_),
            size_(0),
            mlf_(x.mlf_),
            max_load_(x.max_load_),
            buckets_()
        {}

        ////////////////////////////////////////////////////////////////////////
        // Initialisation.

        void init(table const& x)
        {
            if (x.size_) {
                static_cast<table_impl*>(this)->copy_buckets(x);
            }
        }

        void move_init(table& x)
        {
            if(node_alloc() == x.node_alloc()) {
                move_buckets_from(x);
            }
            else if(x.size_) {
                // TODO: Could pick new bucket size?
                static_cast<table_impl*>(this)->move_buckets(x);
            }
        }

        ////////////////////////////////////////////////////////////////////////
        // Create buckets

        void create_buckets(std::size_t new_count)
        {
            std::size_t length = new_count + 1;
            bucket_pointer new_buckets = bucket_allocator_traits::allocate(
                    bucket_alloc(), length);
            bucket_pointer constructed = new_buckets;

            BOOST_TRY {
                bucket_pointer end = new_buckets
                    + static_cast<std::ptrdiff_t>(length);
                for(; constructed != end; ++constructed) {
                    new ((void*) boost::addressof(*constructed)) bucket();
                }

                if (buckets_)
                {
                    // Copy the nodes to the new buckets, including the dummy
                    // node if there is one.
                    (new_buckets +
                        static_cast<std::ptrdiff_t>(new_count))->next_ =
                            (buckets_ + static_cast<std::ptrdiff_t>(
                                bucket_count_))->next_;
                    destroy_buckets();
                }
                else if (bucket::extra_node)
                {
                    node_constructor a(node_alloc());
                    a.create_node();

                    (new_buckets +
                        static_cast<std::ptrdiff_t>(new_count))->next_ =
                            a.release();
                }
            }
            BOOST_CATCH(...) {
                for(bucket_pointer p = new_buckets; p != constructed; ++p) {
                    boost::unordered::detail::func::destroy(
                            boost::addressof(*p));
                }

                bucket_allocator_traits::deallocate(bucket_alloc(),
                        new_buckets, length);

                BOOST_RETHROW;
            }
            BOOST_CATCH_END

            bucket_count_ = new_count;
            buckets_ = new_buckets;
            recalculate_max_load();
        }

        ////////////////////////////////////////////////////////////////////////
        // Swap and Move

        void swap_allocators(table& other, false_type)
        {
            boost::unordered::detail::func::ignore_unused_variable_warning(other);

            // According to 23.2.1.8, if propagate_on_container_swap is
            // false the behaviour is undefined unless the allocators
            // are equal.
            BOOST_ASSERT(node_alloc() == other.node_alloc());
        }

        void swap_allocators(table& other, true_type)
        {
            allocators_.swap(other.allocators_);
        }

        // Only swaps the allocators if propagate_on_container_swap
        void swap(table& x)
        {
            set_hash_functions op1(*this, x);
            set_hash_functions op2(x, *this);

            // I think swap can throw if Propagate::value,
            // since the allocators' swap can throw. Not sure though.
            swap_allocators(x,
                boost::unordered::detail::integral_constant<bool,
                    allocator_traits<node_allocator>::
                    propagate_on_container_swap::value>());

            boost::swap(buckets_, x.buckets_);
            boost::swap(bucket_count_, x.bucket_count_);
            boost::swap(size_, x.size_);
            std::swap(mlf_, x.mlf_);
            std::swap(max_load_, x.max_load_);
            op1.commit();
            op2.commit();
        }

        // Only call with nodes allocated with the currect allocator, or
        // one that is equal to it. (Can't assert because other's
        // allocators might have already been moved).
        void move_buckets_from(table& other)
        {
            BOOST_ASSERT(!buckets_);
            buckets_ = other.buckets_;
            bucket_count_ = other.bucket_count_;
            size_ = other.size_;
            other.buckets_ = bucket_pointer();
            other.size_ = 0;
            other.max_load_ = 0;
        }

        ////////////////////////////////////////////////////////////////////////
        // Delete/destruct

        ~table()
        {
            delete_buckets();
        }

        void delete_node(link_pointer prev)
        {
            node_pointer n = static_cast<node_pointer>(prev->next_);
            prev->next_ = n->next_;

            boost::unordered::detail::func::call_destroy(node_alloc(),
                n->value_ptr());
            boost::unordered::detail::func::destroy(boost::addressof(*n));
            node_allocator_traits::deallocate(node_alloc(), n, 1);
            --size_;
        }

        std::size_t delete_nodes(link_pointer prev, link_pointer end)
        {
            BOOST_ASSERT(prev->next_ != end);

            std::size_t count = 0;

            do {
                delete_node(prev);
                ++count;
            } while (prev->next_ != end);

            return count;
        }

        void delete_buckets()
        {
            if(buckets_) {
                if (size_) delete_nodes(get_previous_start(), link_pointer());

                if (bucket::extra_node) {
                    node_pointer n = static_cast<node_pointer>(
                            get_bucket(bucket_count_)->next_);
                    boost::unordered::detail::func::destroy(
                            boost::addressof(*n));
                    node_allocator_traits::deallocate(node_alloc(), n, 1);
                }

                destroy_buckets();
                buckets_ = bucket_pointer();
                max_load_ = 0;
            }

            BOOST_ASSERT(!size_);
        }

        void clear()
        {
            if (!size_) return;

            delete_nodes(get_previous_start(), link_pointer());
            clear_buckets();

            BOOST_ASSERT(!size_);
        }

        void clear_buckets()
        {
            bucket_pointer end = get_bucket(bucket_count_);
            for(bucket_pointer it = buckets_; it != end; ++it)
            {
                it->next_ = node_pointer();
            }
        }

        void destroy_buckets()
        {
            bucket_pointer end = get_bucket(bucket_count_ + 1);
            for(bucket_pointer it = buckets_; it != end; ++it)
            {
                boost::unordered::detail::func::destroy(
                    boost::addressof(*it));
            }

            bucket_allocator_traits::deallocate(bucket_alloc(),
                buckets_, bucket_count_ + 1);
        }

        ////////////////////////////////////////////////////////////////////////
        // Fix buckets after delete
        //

        std::size_t fix_bucket(std::size_t bucket_index, link_pointer prev)
        {
            link_pointer end = prev->next_;
            std::size_t bucket_index2 = bucket_index;

            if (end)
            {
                bucket_index2 = hash_to_bucket(
                    static_cast<node_pointer>(end)->hash_);

                // If begin and end are in the same bucket, then
                // there's nothing to do.
                if (bucket_index == bucket_index2) return bucket_index2;

                // Update the bucket containing end.
                get_bucket(bucket_index2)->next_ = prev;
            }

            // Check if this bucket is now empty.
            bucket_pointer this_bucket = get_bucket(bucket_index);
            if (this_bucket->next_ == prev)
                this_bucket->next_ = link_pointer();

            return bucket_index2;
        }

        ////////////////////////////////////////////////////////////////////////
        // Assignment

        void assign(table const& x)
        {
            if (this != boost::addressof(x))
            {
                assign(x,
                    boost::unordered::detail::integral_constant<bool,
                        allocator_traits<node_allocator>::
                        propagate_on_container_copy_assignment::value>());
            }
        }

        void assign(table const& x, false_type)
        {
            // Strong exception safety.
            set_hash_functions new_func_this(*this, x);
            mlf_ = x.mlf_;
            recalculate_max_load();

            if (!size_ && !x.size_) {
                new_func_this.commit();
                return;
            }

            if (x.size_ >= max_load_) {
                create_buckets(min_buckets_for_size(x.size_));
            }
            else {
                clear_buckets();
            }

            new_func_this.commit();
            static_cast<table_impl*>(this)->assign_buckets(x);
        }

        void assign(table const& x, true_type)
        {
            if (node_alloc() == x.node_alloc()) {
                allocators_.assign(x.allocators_);
                assign(x, false_type());
            }
            else {
                set_hash_functions new_func_this(*this, x);

                // Delete everything with current allocators before assigning
                // the new ones.
                delete_buckets();
                allocators_.assign(x.allocators_);

                // Copy over other data, all no throw.
                new_func_this.commit();
                mlf_ = x.mlf_;
                bucket_count_ = min_buckets_for_size(x.size_);
                max_load_ = 0;

                // Finally copy the elements.
                if (x.size_) {
                    static_cast<table_impl*>(this)->copy_buckets(x);
                }
            }
        }

        void move_assign(table& x)
        {
            if (this != boost::addressof(x))
            {
                move_assign(x,
                    boost::unordered::detail::integral_constant<bool,
                        allocator_traits<node_allocator>::
                        propagate_on_container_move_assignment::value>());
            }
        }

        void move_assign(table& x, true_type)
        {
            delete_buckets();
            set_hash_functions new_func_this(*this, x);
            allocators_.move_assign(x.allocators_);
            // No throw from here.
            mlf_ = x.mlf_;
            max_load_ = x.max_load_;
            move_buckets_from(x);
            new_func_this.commit();
        }

        void move_assign(table& x, false_type)
        {
            if (node_alloc() == x.node_alloc()) {
                delete_buckets();
                set_hash_functions new_func_this(*this, x);
                // No throw from here.
                mlf_ = x.mlf_;
                max_load_ = x.max_load_;
                move_buckets_from(x);
                new_func_this.commit();
            }
            else {
                set_hash_functions new_func_this(*this, x);
                mlf_ = x.mlf_;
                recalculate_max_load();

                if (!size_ && !x.size_) {
                    new_func_this.commit();
                    return;
                }

                if (x.size_ >= max_load_) {
                    create_buckets(min_buckets_for_size(x.size_));
                }
                else {
                    clear_buckets();
                }

                new_func_this.commit();
                static_cast<table_impl*>(this)->move_assign_buckets(x);
            }
        }

        // Accessors

        key_type const& get_key(value_type const& x) const
        {
            return extractor::extract(x);
        }

        std::size_t hash(key_type const& k) const
        {
            return policy::apply_hash(this->hash_function(), k);
        }

        // Find Node

        template <typename Key, typename Hash, typename Pred>
        node_pointer generic_find_node(
                Key const& k,
                Hash const& hf,
                Pred const& eq) const
        {
            return static_cast<table_impl const*>(this)->
                find_node_impl(policy::apply_hash(hf, k), k, eq);
        }

        node_pointer find_node(
                std::size_t key_hash,
                key_type const& k) const
        {
            return static_cast<table_impl const*>(this)->
                find_node_impl(key_hash, k, this->key_eq());
        }

        node_pointer find_node(key_type const& k) const
        {
            return static_cast<table_impl const*>(this)->
                find_node_impl(hash(k), k, this->key_eq());
        }

        // Reserve and rehash

        void reserve_for_insert(std::size_t);
        void rehash(std::size_t);
        void reserve(std::size_t);
    };

    ////////////////////////////////////////////////////////////////////////////
    // Reserve & Rehash

    // basic exception safety
    template <typename Types>
    inline void table<Types>::reserve_for_insert(std::size_t size)
    {
        if (!buckets_) {
            create_buckets((std::max)(bucket_count_,
                min_buckets_for_size(size)));
        }
        // According to the standard this should be 'size >= max_load_',
        // but I think this is better, defect report filed.
        else if(size > max_load_) {
            std::size_t num_buckets
                = min_buckets_for_size((std::max)(size,
                    size_ + (size_ >> 1)));

            if (num_buckets != bucket_count_)
                static_cast<table_impl*>(this)->rehash_impl(num_buckets);
        }
    }

    // if hash function throws, basic exception safety
    // strong otherwise.

    template <typename Types>
    inline void table<Types>::rehash(std::size_t min_buckets)
    {
        using namespace std;

        if(!size_) {
            delete_buckets();
            bucket_count_ = policy::new_bucket_count(min_buckets);
        }
        else {
            min_buckets = policy::new_bucket_count((std::max)(min_buckets,
                boost::unordered::detail::double_to_size(floor(
                    static_cast<double>(size_) /
                    static_cast<double>(mlf_))) + 1));

            if(min_buckets != bucket_count_)
                static_cast<table_impl*>(this)->rehash_impl(min_buckets);
        }
    }

    template <typename Types>
    inline void table<Types>::reserve(std::size_t num_elements)
    {
        rehash(static_cast<std::size_t>(
            std::ceil(static_cast<double>(num_elements) / mlf_)));
    }
}}}

#if defined(BOOST_MSVC)
#pragma warning(pop)
#endif

namespace boost {
namespace unordered {
namespace detail {

    // key extractors
    //
    // no throw
    //
    // 'extract_key' is called with the emplace parameters to return a
    // key if available or 'no_key' is one isn't and will need to be
    // constructed. This could be done by overloading the emplace implementation
    // for the different cases, but that's a bit tricky on compilers without
    // variadic templates.

    struct no_key {
        no_key() {}
        template <class T> no_key(T const&) {}
    };

    template <typename Key, typename T>
    struct is_key {
        template <typename T2>
        static choice1::type test(T2 const&);
        static choice2::type test(Key const&);

        enum { value = sizeof(test(boost::unordered::detail::make<T>())) ==
            sizeof(choice2::type) };

        typedef typename boost::detail::if_true<value>::
            BOOST_NESTED_TEMPLATE then<Key const&, no_key>::type type;
    };

    template <class ValueType>
    struct set_extractor
    {
        typedef ValueType value_type;
        typedef ValueType key_type;

        static key_type const& extract(value_type const& v)
        {
            return v;
        }

        static no_key extract()
        {
            return no_key();
        }

        template <class Arg>
        static no_key extract(Arg const&)
        {
            return no_key();
        }

#if !defined(BOOST_NO_CXX11_VARIADIC_TEMPLATES)
        template <class Arg1, class Arg2, class... Args>
        static no_key extract(Arg1 const&, Arg2 const&, Args const&...)
        {
            return no_key();
        }
#else
        template <class Arg1, class Arg2>
        static no_key extract(Arg1 const&, Arg2 const&)
        {
            return no_key();
        }
#endif
    };

    template <class Key, class ValueType>
    struct map_extractor
    {
        typedef ValueType value_type;
        typedef typename boost::remove_const<Key>::type key_type;

        static key_type const& extract(value_type const& v)
        {
            return v.first;
        }

        template <class Second>
        static key_type const& extract(std::pair<key_type, Second> const& v)
        {
            return v.first;
        }

        template <class Second>
        static key_type const& extract(
            std::pair<key_type const, Second> const& v)
        {
            return v.first;
        }

        template <class Arg1>
        static key_type const& extract(key_type const& k, Arg1 const&)
        {
            return k;
        }

        static no_key extract()
        {
            return no_key();
        }

        template <class Arg>
        static no_key extract(Arg const&)
        {
            return no_key();
        }

        template <class Arg1, class Arg2>
        static no_key extract(Arg1 const&, Arg2 const&)
        {
            return no_key();
        }

#if !defined(BOOST_NO_CXX11_VARIADIC_TEMPLATES)
        template <class Arg1, class Arg2, class Arg3, class... Args>
        static no_key extract(Arg1 const&, Arg2 const&, Arg3 const&,
                Args const&...)
        {
            return no_key();
        }
#endif

#if !defined(BOOST_NO_CXX11_VARIADIC_TEMPLATES)

#define BOOST_UNORDERED_KEY_FROM_TUPLE(namespace_)                          \
        template <typename T2>                                              \
        static no_key extract(boost::unordered::piecewise_construct_t,      \
                namespace_ tuple<> const&, T2 const&)                       \
        {                                                                   \
            return no_key();                                                \
        }                                                                   \
                                                                            \
        template <typename T, typename T2>                                  \
        static typename is_key<key_type, T>::type                           \
            extract(boost::unordered::piecewise_construct_t,                \
                namespace_ tuple<T> const& k, T2 const&)                    \
        {                                                                   \
            return typename is_key<key_type, T>::type(                      \
                namespace_ get<0>(k));                                      \
        }

#else

#define BOOST_UNORDERED_KEY_FROM_TUPLE(namespace_)                          \
        static no_key extract(boost::unordered::piecewise_construct_t,      \
                namespace_ tuple<> const&)                                  \
        {                                                                   \
            return no_key();                                                \
        }                                                                   \
                                                                            \
        template <typename T>                                               \
        static typename is_key<key_type, T>::type                           \
            extract(boost::unordered::piecewise_construct_t,                \
                namespace_ tuple<T> const& k)                               \
        {                                                                   \
            return typename is_key<key_type, T>::type(                      \
                namespace_ get<0>(k));                                      \
        }

#endif

BOOST_UNORDERED_KEY_FROM_TUPLE(boost::)

#if !defined(BOOST_NO_CXX11_HDR_TUPLE)
BOOST_UNORDERED_KEY_FROM_TUPLE(std::)
#endif
    };
}}}

namespace boost { namespace unordered { namespace detail {

    template <typename A, typename T> struct unique_node;
    template <typename T> struct ptr_node;
    template <typename Types> struct table_impl;

    template <typename A, typename T>
    struct unique_node :
        boost::unordered::detail::value_base<T>
    {
        typedef typename ::boost::unordered::detail::rebind_wrap<
            A, unique_node<A, T> >::type allocator;
        typedef typename ::boost::unordered::detail::
            allocator_traits<allocator>::pointer node_pointer;
        typedef node_pointer link_pointer;

        link_pointer next_;
        std::size_t hash_;

        unique_node() :
            next_(),
            hash_(0)
        {}

        void init(node_pointer)
        {
        }

    private:
        unique_node& operator=(unique_node const&);
    };

    template <typename T>
    struct ptr_node :
        boost::unordered::detail::ptr_bucket
    {
        typedef T value_type;
        typedef boost::unordered::detail::ptr_bucket bucket_base;
        typedef ptr_node<T>* node_pointer;
        typedef ptr_bucket* link_pointer;

        std::size_t hash_;
        boost::unordered::detail::value_base<T> value_base_;

        ptr_node() :
            bucket_base(),
            hash_(0)
        {}

        void init(node_pointer)
        {
        }

        void* address() { return value_base_.address(); }
        value_type& value() { return value_base_.value(); }
        value_type* value_ptr() { return value_base_.value_ptr(); }

    private:
        ptr_node& operator=(ptr_node const&);
    };

    // If the allocator uses raw pointers use ptr_node
    // Otherwise use node.

    template <typename A, typename T, typename NodePtr, typename BucketPtr>
    struct pick_node2
    {
        typedef boost::unordered::detail::unique_node<A, T> node;

        typedef typename boost::unordered::detail::allocator_traits<
            typename boost::unordered::detail::rebind_wrap<A, node>::type
        >::pointer node_pointer;

        typedef boost::unordered::detail::bucket<node_pointer> bucket;
        typedef node_pointer link_pointer;
    };

    template <typename A, typename T>
    struct pick_node2<A, T,
        boost::unordered::detail::ptr_node<T>*,
        boost::unordered::detail::ptr_bucket*>
    {
        typedef boost::unordered::detail::ptr_node<T> node;
        typedef boost::unordered::detail::ptr_bucket bucket;
        typedef bucket* link_pointer;
    };

    template <typename A, typename T>
    struct pick_node
    {
        typedef typename boost::remove_const<T>::type nonconst;

        typedef boost::unordered::detail::allocator_traits<
            typename boost::unordered::detail::rebind_wrap<A,
                boost::unordered::detail::ptr_node<nonconst> >::type
        > tentative_node_traits;

        typedef boost::unordered::detail::allocator_traits<
            typename boost::unordered::detail::rebind_wrap<A,
                boost::unordered::detail::ptr_bucket >::type
        > tentative_bucket_traits;

        typedef pick_node2<A, nonconst,
            typename tentative_node_traits::pointer,
            typename tentative_bucket_traits::pointer> pick;

        typedef typename pick::node node;
        typedef typename pick::bucket bucket;
        typedef typename pick::link_pointer link_pointer;
    };

    template <typename Types>
    struct table_impl : boost::unordered::detail::table<Types>
    {
        typedef boost::unordered::detail::table<Types> table;
        typedef typename table::value_type value_type;
        typedef typename table::bucket bucket;
        typedef typename table::policy policy;
        typedef typename table::node_pointer node_pointer;
        typedef typename table::node_allocator node_allocator;
        typedef typename table::node_allocator_traits node_allocator_traits;
        typedef typename table::bucket_pointer bucket_pointer;
        typedef typename table::link_pointer link_pointer;
        typedef typename table::hasher hasher;
        typedef typename table::key_equal key_equal;
        typedef typename table::key_type key_type;
        typedef typename table::node_constructor node_constructor;
        typedef typename table::node_tmp node_tmp;
        typedef typename table::extractor extractor;
        typedef typename table::iterator iterator;
        typedef typename table::c_iterator c_iterator;

        typedef std::pair<iterator, bool> emplace_return;

        // Constructors

        table_impl(std::size_t n,
                hasher const& hf,
                key_equal const& eq,
                node_allocator const& a)
          : table(n, hf, eq, a)
        {}

        table_impl(table_impl const& x)
          : table(x, node_allocator_traits::
                select_on_container_copy_construction(x.node_alloc()))
        {
            this->init(x);
        }

        table_impl(table_impl const& x,
                node_allocator const& a)
          : table(x, a)
        {
            this->init(x);
        }

        table_impl(table_impl& x,
                boost::unordered::detail::move_tag m)
          : table(x, m)
        {}

        table_impl(table_impl& x,
                node_allocator const& a,
                boost::unordered::detail::move_tag m)
          : table(x, a, m)
        {
            this->move_init(x);
        }

        // Node functions.

        static inline node_pointer next_node(link_pointer n) {
            return static_cast<node_pointer>(n->next_);
        }

        // Accessors

        template <class Key, class Pred>
        node_pointer find_node_impl(
                std::size_t key_hash,
                Key const& k,
                Pred const& eq) const
        {
            std::size_t bucket_index = this->hash_to_bucket(key_hash);
            node_pointer n = this->begin(bucket_index);

            for (;;)
            {
                if (!n) return n;

                std::size_t node_hash = n->hash_;
                if (key_hash == node_hash)
                {
                    if (eq(k, this->get_key(n->value())))
                        return n;
                }
                else
                {
                    if (this->hash_to_bucket(node_hash) != bucket_index)
                        return node_pointer();
                }

                n = next_node(n);
            }
        }

        std::size_t count(key_type const& k) const
        {
            return this->find_node(k) ? 1 : 0;
        }

        value_type& at(key_type const& k) const
        {
            if (this->size_) {
                node_pointer n = this->find_node(k);
                if (n) return n->value();
            }

            boost::throw_exception(
                std::out_of_range("Unable to find key in unordered_map."));
        }

        std::pair<iterator, iterator>
            equal_range(key_type const& k) const
        {
            node_pointer n = this->find_node(k);
            return std::make_pair(iterator(n), iterator(n ? next_node(n) : n));
        }

        // equals

        bool equals(table_impl const& other) const
        {
            if(this->size_ != other.size_) return false;

            for(node_pointer n1 = this->begin(); n1; n1 = next_node(n1))
            {
                node_pointer n2 = other.find_node(other.get_key(n1->value()));

                if (!n2 || n1->value() != n2->value())
                    return false;
            }

            return true;
        }

        // Emplace/Insert

        inline node_pointer add_node(
                node_pointer n,
                std::size_t key_hash)
        {
            n->hash_ = key_hash;

            bucket_pointer b = this->get_bucket(this->hash_to_bucket(key_hash));

            if (!b->next_)
            {
                link_pointer start_node = this->get_previous_start();

                if (start_node->next_) {
                    this->get_bucket(this->hash_to_bucket(
                        next_node(start_node)->hash_)
                    )->next_ = n;
                }

                b->next_ = start_node;
                n->next_ = start_node->next_;
                start_node->next_ = n;
            }
            else
            {
                n->next_ = b->next_->next_;
                b->next_->next_ = n;
            }

            ++this->size_;
            return n;
        }

        inline node_pointer resize_and_add_node(node_pointer n, std::size_t key_hash)
        {
            node_tmp b(n, this->node_alloc());
            this->reserve_for_insert(this->size_ + 1);
            return this->add_node(b.release(), key_hash);
        }

        value_type& operator[](key_type const& k)
        {
            std::size_t key_hash = this->hash(k);
            node_pointer pos = this->find_node(key_hash, k);
            if (pos) {
                return pos->value();
            }
            else {
                return this->resize_and_add_node(
                    boost::unordered::detail::func::construct_node_pair(this->node_alloc(), k),
                    key_hash)->value();
            }
        }

#if defined(BOOST_NO_CXX11_RVALUE_REFERENCES)
#   if defined(BOOST_NO_CXX11_VARIADIC_TEMPLATES)
        emplace_return emplace(boost::unordered::detail::emplace_args1<
                boost::unordered::detail::please_ignore_this_overload> const&)
        {
            BOOST_ASSERT(false);
            return emplace_return(iterator(), false);
        }

        iterator emplace_hint(c_iterator,
            boost::unordered::detail::emplace_args1<
                boost::unordered::detail::please_ignore_this_overload> const&)
        {
            BOOST_ASSERT(false);
            return iterator();
        }
#   else
        emplace_return emplace(
                boost::unordered::detail::please_ignore_this_overload const&)
        {
            BOOST_ASSERT(false);
            return emplace_return(iterator(), false);
        }

        iterator emplace_hint(c_iterator,
                boost::unordered::detail::please_ignore_this_overload const&)
        {
            BOOST_ASSERT(false);
            return iterator();
        }
#   endif
#endif

        template <BOOST_UNORDERED_EMPLACE_TEMPLATE>
        emplace_return emplace(BOOST_UNORDERED_EMPLACE_ARGS)
        {
#if !defined(BOOST_NO_CXX11_VARIADIC_TEMPLATES)
            return emplace_impl(
                extractor::extract(BOOST_UNORDERED_EMPLACE_FORWARD),
                BOOST_UNORDERED_EMPLACE_FORWARD);
#else
            return emplace_impl(
                extractor::extract(args.a0, args.a1),
                BOOST_UNORDERED_EMPLACE_FORWARD);
#endif
        }

        template <BOOST_UNORDERED_EMPLACE_TEMPLATE>
        iterator emplace_hint(c_iterator hint,
            BOOST_UNORDERED_EMPLACE_ARGS)
        {
#if !defined(BOOST_NO_CXX11_VARIADIC_TEMPLATES)
            return emplace_hint_impl(hint,
                extractor::extract(BOOST_UNORDERED_EMPLACE_FORWARD),
                BOOST_UNORDERED_EMPLACE_FORWARD);
#else
            return emplace_hint_impl(hint,
                extractor::extract(args.a0, args.a1),
                BOOST_UNORDERED_EMPLACE_FORWARD);
#endif
        }

#if defined(BOOST_NO_CXX11_VARIADIC_TEMPLATES)
        template <typename A0>
        emplace_return emplace(
                boost::unordered::detail::emplace_args1<A0> const& args)
        {
            return emplace_impl(extractor::extract(args.a0), args);
        }

        template <typename A0>
        iterator emplace_hint(c_iterator hint,
                boost::unordered::detail::emplace_args1<A0> const& args)
        {
            return emplace_hint_impl(hint, extractor::extract(args.a0), args);
        }
#endif

        template <BOOST_UNORDERED_EMPLACE_TEMPLATE>
        iterator emplace_hint_impl(c_iterator hint, key_type const& k,
            BOOST_UNORDERED_EMPLACE_ARGS)
        {
            if (hint.node_ && this->key_eq()(k, this->get_key(*hint))) {
                return iterator(hint.node_);
            }
            else {
                return emplace_impl(k, BOOST_UNORDERED_EMPLACE_FORWARD).first;
            }
        }

        template <BOOST_UNORDERED_EMPLACE_TEMPLATE>
        emplace_return emplace_impl(key_type const& k,
            BOOST_UNORDERED_EMPLACE_ARGS)
        {
            std::size_t key_hash = this->hash(k);
            node_pointer pos = this->find_node(key_hash, k);
            if (pos) {
                return emplace_return(iterator(pos), false);
            }
            else {
                return emplace_return(
                    iterator(this->resize_and_add_node(
                        boost::unordered::detail::func::construct_node_from_args(
                            this->node_alloc(), BOOST_UNORDERED_EMPLACE_FORWARD),
                        key_hash)),
                    true);
            }
        }

        template <BOOST_UNORDERED_EMPLACE_TEMPLATE>
        iterator emplace_hint_impl(c_iterator hint, no_key,
            BOOST_UNORDERED_EMPLACE_ARGS)
        {
            node_tmp b(
                boost::unordered::detail::func::construct_node_from_args(
                    this->node_alloc(), BOOST_UNORDERED_EMPLACE_FORWARD),
                this->node_alloc());
            key_type const& k = this->get_key(b.node_->value());
            if (hint.node_ && this->key_eq()(k, this->get_key(*hint))) {
                return iterator(hint.node_);
            }
            std::size_t key_hash = this->hash(k);
            node_pointer pos = this->find_node(key_hash, k);
            if (pos) {
                return iterator(pos);
            }
            else {
                return iterator(this->resize_and_add_node(b.release(), key_hash));
            }
        }

        template <BOOST_UNORDERED_EMPLACE_TEMPLATE>
        emplace_return emplace_impl(no_key, BOOST_UNORDERED_EMPLACE_ARGS)
        {
            node_tmp b(
                boost::unordered::detail::func::construct_node_from_args(
                    this->node_alloc(), BOOST_UNORDERED_EMPLACE_FORWARD),
                this->node_alloc());
            key_type const& k = this->get_key(b.node_->value());
            std::size_t key_hash = this->hash(k);
            node_pointer pos = this->find_node(key_hash, k);
            if (pos) {
                return emplace_return(iterator(pos), false);
            }
            else {
                return emplace_return(
                    iterator(this->resize_and_add_node(b.release(), key_hash)),
                    true);
            }
        }

        ////////////////////////////////////////////////////////////////////////
        // Insert range methods
        //
        // if hash function throws, or inserting > 1 element, basic exception
        // safety strong otherwise

        template <class InputIt>
        void insert_range(InputIt i, InputIt j)
        {
            if(i != j)
                return insert_range_impl(extractor::extract(*i), i, j);
        }

        template <class InputIt>
        void insert_range_impl(key_type const& k, InputIt i, InputIt j)
        {
            insert_range_impl2(k, i, j);

            while(++i != j) {
                // Note: can't use get_key as '*i' might not be value_type - it
                // could be a pair with first_types as key_type without const or
                // a different second_type.
                //
                // TODO: Might be worth storing the value_type instead of the
                // key here. Could be more efficient if '*i' is expensive. Could
                // be less efficient if copying the full value_type is
                // expensive.
                insert_range_impl2(extractor::extract(*i), i, j);
            }
        }

        template <class InputIt>
        void insert_range_impl2(key_type const& k, InputIt i, InputIt j)
        {
            // No side effects in this initial code
            std::size_t key_hash = this->hash(k);
            node_pointer pos = this->find_node(key_hash, k);

            if (!pos) {
                node_tmp b(
                    boost::unordered::detail::func::construct_node(this->node_alloc(), *i),
                    this->node_alloc());
                if(this->size_ + 1 > this->max_load_)
                    this->reserve_for_insert(this->size_ +
                        boost::unordered::detail::insert_size(i, j));
                this->add_node(b.release(), key_hash);
            }
        }

        template <class InputIt>
        void insert_range_impl(no_key, InputIt i, InputIt j)
        {
            node_constructor a(this->node_alloc());

            do {
                if (!a.node_) { a.create_node(); }
                boost::unordered::detail::func::call_construct(
                    a.alloc_, a.node_->value_ptr(), *i);
                node_tmp b(a.release(), a.alloc_);

                key_type const& k = this->get_key(b.node_->value());
                std::size_t key_hash = this->hash(k);
                node_pointer pos = this->find_node(key_hash, k);

                if (pos) {
                    a.reclaim(b.release());
                }
                else {
                    // reserve has basic exception safety if the hash function
                    // throws, strong otherwise.
                    this->reserve_for_insert(this->size_ + 1);
                    this->add_node(b.release(), key_hash);
                }
            } while(++i != j);
        }

        ////////////////////////////////////////////////////////////////////////
        // Erase
        //
        // no throw

        std::size_t erase_key(key_type const& k)
        {
            if(!this->size_) return 0;

            std::size_t key_hash = this->hash(k);
            std::size_t bucket_index = this->hash_to_bucket(key_hash);
            link_pointer prev = this->get_previous_start(bucket_index);
            if (!prev) return 0;

            for (;;)
            {
                if (!prev->next_) return 0;
                std::size_t node_hash = next_node(prev)->hash_;
                if (this->hash_to_bucket(node_hash) != bucket_index)
                    return 0;
                if (node_hash == key_hash &&
                        this->key_eq()(k, this->get_key(
                        next_node(prev)->value())))
                    break;
                prev = prev->next_;
            }

            link_pointer end = next_node(prev)->next_;

            std::size_t deleted_count = this->delete_nodes(prev, end);
            this->fix_bucket(bucket_index, prev);
            return deleted_count;
        }

        iterator erase(c_iterator r)
        {
            BOOST_ASSERT(r.node_);
            node_pointer next = next_node(r.node_);
            erase_nodes(r.node_, next);
            return iterator(next);
        }

        iterator erase_range(c_iterator r1, c_iterator r2)
        {
            if (r1 == r2) return iterator(r2.node_);
            erase_nodes(r1.node_, r2.node_);
            return iterator(r2.node_);
        }

        void erase_nodes(node_pointer i, node_pointer j)
        {
            std::size_t bucket_index = this->hash_to_bucket(i->hash_);

            // Find the node before i.
            link_pointer prev = this->get_previous_start(bucket_index);
            while(prev->next_ != i) prev = prev->next_;

            // Delete the nodes.
            do {
                this->delete_node(prev);
                bucket_index = this->fix_bucket(bucket_index, prev);
            } while (prev->next_ != j);
        }

        ////////////////////////////////////////////////////////////////////////
        // fill_buckets

        void copy_buckets(table const& src) {
            this->create_buckets(this->bucket_count_);

            for(node_pointer n = src.begin(); n; n = next_node(n)) {
                this->add_node(
                    boost::unordered::detail::func::construct_node(
                     this->node_alloc(), n->value()), n->hash_);
            }
        }

        void move_buckets(table const& src) {
            this->create_buckets(this->bucket_count_);

            for(node_pointer n = src.begin(); n; n = next_node(n)) {
                this->add_node(
                    boost::unordered::detail::func::construct_node(
                        this->node_alloc(), boost::move(n->value())), n->hash_);
            }
        }

        void assign_buckets(table const& src)
        {
            node_holder<node_allocator> holder(*this);
            for(node_pointer n = src.begin(); n; n = next_node(n)) {
                this->add_node(holder.copy_of(n->value()), n->hash_);
            }
        }

        void move_assign_buckets(table& src)
        {
            node_holder<node_allocator> holder(*this);
            for(node_pointer n = src.begin(); n; n = next_node(n)) {
                this->add_node(holder.move_copy_of(n->value()), n->hash_);
            }
        }

        // strong otherwise exception safety
        void rehash_impl(std::size_t num_buckets)
        {
            BOOST_ASSERT(this->buckets_);

            this->create_buckets(num_buckets);
            link_pointer prev = this->get_previous_start();
            while (prev->next_)
                prev = place_in_bucket(*this, prev);
        }

        // Iterate through the nodes placing them in the correct buckets.
        // pre: prev->next_ is not null.
        static link_pointer place_in_bucket(table& dst, link_pointer prev)
        {
            node_pointer n = next_node(prev);
            bucket_pointer b = dst.get_bucket(dst.hash_to_bucket(n->hash_));

            if (!b->next_) {
                b->next_ = prev;
                return n;
            }
            else {
                prev->next_ = n->next_;
                n->next_ = b->next_->next_;
                b->next_->next_ = n;
                return prev;
            }
        }
    };
}}}

namespace boost { namespace unordered { namespace detail {

    template <typename A, typename T> struct grouped_node;
    template <typename T> struct grouped_ptr_node;
    template <typename Types> struct grouped_table_impl;

    template <typename A, typename T>
    struct grouped_node :
        boost::unordered::detail::value_base<T>
    {
        typedef typename ::boost::unordered::detail::rebind_wrap<
            A, grouped_node<A, T> >::type allocator;
        typedef typename ::boost::unordered::detail::
            allocator_traits<allocator>::pointer node_pointer;
        typedef node_pointer link_pointer;

        link_pointer next_;
        node_pointer group_prev_;
        std::size_t hash_;

        grouped_node() :
            next_(),
            group_prev_(),
            hash_(0)
        {}

        void init(node_pointer self)
        {
            group_prev_ = self;
        }

    private:
        grouped_node& operator=(grouped_node const&);
    };

    template <typename T>
    struct grouped_ptr_node :
        boost::unordered::detail::ptr_bucket
    {
        typedef T value_type;
        typedef boost::unordered::detail::ptr_bucket bucket_base;
        typedef grouped_ptr_node<T>* node_pointer;
        typedef ptr_bucket* link_pointer;

        node_pointer group_prev_;
        std::size_t hash_;
        boost::unordered::detail::value_base<T> value_base_;

        grouped_ptr_node() :
            bucket_base(),
            group_prev_(0),
            hash_(0)
        {}

        void init(node_pointer self)
        {
            group_prev_ = self;
        }

        void* address() { return value_base_.address(); }
        value_type& value() { return value_base_.value(); }
        value_type* value_ptr() { return value_base_.value_ptr(); }

    private:
        grouped_ptr_node& operator=(grouped_ptr_node const&);
    };

    // If the allocator uses raw pointers use grouped_ptr_node
    // Otherwise use grouped_node.

    template <typename A, typename T, typename NodePtr, typename BucketPtr>
    struct pick_grouped_node2
    {
        typedef boost::unordered::detail::grouped_node<A, T> node;

        typedef typename boost::unordered::detail::allocator_traits<
            typename boost::unordered::detail::rebind_wrap<A, node>::type
        >::pointer node_pointer;

        typedef boost::unordered::detail::bucket<node_pointer> bucket;
        typedef node_pointer link_pointer;
    };

    template <typename A, typename T>
    struct pick_grouped_node2<A, T,
        boost::unordered::detail::grouped_ptr_node<T>*,
        boost::unordered::detail::ptr_bucket*>
    {
        typedef boost::unordered::detail::grouped_ptr_node<T> node;
        typedef boost::unordered::detail::ptr_bucket bucket;
        typedef bucket* link_pointer;
    };

    template <typename A, typename T>
    struct pick_grouped_node
    {
        typedef typename boost::remove_const<T>::type nonconst;

        typedef boost::unordered::detail::allocator_traits<
            typename boost::unordered::detail::rebind_wrap<A,
                boost::unordered::detail::grouped_ptr_node<nonconst> >::type
        > tentative_node_traits;

        typedef boost::unordered::detail::allocator_traits<
            typename boost::unordered::detail::rebind_wrap<A,
                boost::unordered::detail::ptr_bucket >::type
        > tentative_bucket_traits;

        typedef pick_grouped_node2<A, nonconst,
            typename tentative_node_traits::pointer,
            typename tentative_bucket_traits::pointer> pick;

        typedef typename pick::node node;
        typedef typename pick::bucket bucket;
        typedef typename pick::link_pointer link_pointer;
    };

    template <typename Types>
    struct grouped_table_impl : boost::unordered::detail::table<Types>
    {
        typedef boost::unordered::detail::table<Types> table;
        typedef typename table::value_type value_type;
        typedef typename table::bucket bucket;
        typedef typename table::policy policy;
        typedef typename table::node_pointer node_pointer;
        typedef typename table::node_allocator node_allocator;
        typedef typename table::node_allocator_traits node_allocator_traits;
        typedef typename table::bucket_pointer bucket_pointer;
        typedef typename table::link_pointer link_pointer;
        typedef typename table::hasher hasher;
        typedef typename table::key_equal key_equal;
        typedef typename table::key_type key_type;
        typedef typename table::node_constructor node_constructor;
        typedef typename table::node_tmp node_tmp;
        typedef typename table::extractor extractor;
        typedef typename table::iterator iterator;
        typedef typename table::c_iterator c_iterator;

        // Constructors

        grouped_table_impl(std::size_t n,
                hasher const& hf,
                key_equal const& eq,
                node_allocator const& a)
          : table(n, hf, eq, a)
        {}

        grouped_table_impl(grouped_table_impl const& x)
          : table(x, node_allocator_traits::
                select_on_container_copy_construction(x.node_alloc()))
        {
            this->init(x);
        }

        grouped_table_impl(grouped_table_impl const& x,
                node_allocator const& a)
          : table(x, a)
        {
            this->init(x);
        }

        grouped_table_impl(grouped_table_impl& x,
                boost::unordered::detail::move_tag m)
          : table(x, m)
        {}

        grouped_table_impl(grouped_table_impl& x,
                node_allocator const& a,
                boost::unordered::detail::move_tag m)
          : table(x, a, m)
        {
            this->move_init(x);
        }

        // Node functions.

        static inline node_pointer next_node(link_pointer n) {
            return static_cast<node_pointer>(n->next_);
        }

        static inline node_pointer next_group(node_pointer n) {
            return static_cast<node_pointer>(n->group_prev_->next_);
        }

        // Accessors

        template <class Key, class Pred>
        node_pointer find_node_impl(
                std::size_t key_hash,
                Key const& k,
                Pred const& eq) const
        {
            std::size_t bucket_index = this->hash_to_bucket(key_hash);
            node_pointer n = this->begin(bucket_index);

            for (;;)
            {
                if (!n) return n;

                std::size_t node_hash = n->hash_;
                if (key_hash == node_hash)
                {
                    if (eq(k, this->get_key(n->value())))
                        return n;
                }
                else
                {
                    if (this->hash_to_bucket(node_hash) != bucket_index)
                        return node_pointer();
                }

                n = next_group(n);
            }
        }

        std::size_t count(key_type const& k) const
        {
            node_pointer n = this->find_node(k);
            if (!n) return 0;

            std::size_t x = 0;
            node_pointer it = n;
            do {
                it = it->group_prev_;
                ++x;
            } while(it != n);

            return x;
        }

        std::pair<iterator, iterator>
            equal_range(key_type const& k) const
        {
            node_pointer n = this->find_node(k);
            return std::make_pair(iterator(n), iterator(n ? next_group(n) : n));
        }

        // Equality

        bool equals(grouped_table_impl const& other) const
        {
            if(this->size_ != other.size_) return false;

            for(node_pointer n1 = this->begin(); n1;)
            {
                node_pointer n2 = other.find_node(other.get_key(n1->value()));
                if (!n2) return false;
                node_pointer end1 = next_group(n1);
                node_pointer end2 = next_group(n2);
                if (!group_equals(n1, end1, n2, end2)) return false;
                n1 = end1;
            }

            return true;
        }

        static bool group_equals(node_pointer n1, node_pointer end1,
                node_pointer n2, node_pointer end2)
        {
            for(;;)
            {
                if (n1->value() != n2->value()) break;

                n1 = next_node(n1);
                n2 = next_node(n2);

                if (n1 == end1) return n2 == end2;
                if (n2 == end2) return false;
            }

            for(node_pointer n1a = n1, n2a = n2;;)
            {
                n1a = next_node(n1a);
                n2a = next_node(n2a);

                if (n1a == end1)
                {
                    if (n2a == end2) break;
                    else return false;
                }

                if (n2a == end2) return false;
            }

            node_pointer start = n1;
            for(;n1 != end1; n1 = next_node(n1))
            {
                value_type const& v = n1->value();
                if (!find(start, n1, v)) {
                    std::size_t matches = count_equal(n2, end2, v);
                    if (!matches) return false;
                    if (matches != 1 + count_equal(next_node(n1), end1, v)) return false;
                }
            }

            return true;
        }

        static bool find(node_pointer n, node_pointer end, value_type const& v)
        {
            for(;n != end; n = next_node(n))
                if (n->value() == v)
                    return true;
            return false;
        }

        static std::size_t count_equal(node_pointer n, node_pointer end,
            value_type const& v)
        {
            std::size_t count = 0;
            for(;n != end; n = next_node(n))
                if (n->value() == v) ++count;
            return count;
        }

        // Emplace/Insert

        // Add node 'n' to the group containing 'pos'.
        // If 'pos' is the first node in group, add to the end of the group,
        // otherwise add before 'pos'.
        static inline void add_to_node_group(
                node_pointer n,
                node_pointer pos)
        {
            n->next_ = pos->group_prev_->next_;
            n->group_prev_ = pos->group_prev_;
            pos->group_prev_->next_ = n;
            pos->group_prev_ = n;
        }

        inline node_pointer add_node(
                node_pointer n,
                std::size_t key_hash,
                node_pointer pos)
        {
            n->hash_ = key_hash;
            if (pos) {
                this->add_to_node_group(n, pos);
                if (n->next_) {
                    std::size_t next_bucket = this->hash_to_bucket(
                        next_node(n)->hash_);
                    if (next_bucket != this->hash_to_bucket(key_hash)) {
                        this->get_bucket(next_bucket)->next_ = n;
                    }
                }
            }
            else {
                bucket_pointer b = this->get_bucket(
                    this->hash_to_bucket(key_hash));

                if (!b->next_)
                {
                    link_pointer start_node = this->get_previous_start();

                    if (start_node->next_) {
                        this->get_bucket(this->hash_to_bucket(
                            next_node(start_node)->hash_
                        ))->next_ = n;
                    }

                    b->next_ = start_node;
                    n->next_ = start_node->next_;
                    start_node->next_ = n;
                }
                else
                {
                    n->next_ = b->next_->next_;
                    b->next_->next_ = n;
                }
            }
            ++this->size_;
            return n;
        }

        inline node_pointer add_using_hint(
                node_pointer n,
                node_pointer hint)
        {
            n->hash_ = hint->hash_;
            this->add_to_node_group(n, hint);
            if (n->next_ != hint && n->next_) {
                std::size_t next_bucket = this->hash_to_bucket(
                    next_node(n)->hash_);
                if (next_bucket != this->hash_to_bucket(n->hash_)) {
                    this->get_bucket(next_bucket)->next_ = n;
                }
            }
            ++this->size_;
            return n;
        }


#if defined(BOOST_NO_CXX11_RVALUE_REFERENCES)
#   if defined(BOOST_NO_CXX11_VARIADIC_TEMPLATES)
        iterator emplace(boost::unordered::detail::emplace_args1<
                boost::unordered::detail::please_ignore_this_overload> const&)
        {
            BOOST_ASSERT(false);
            return iterator();
        }

        iterator emplace_hint(c_iterator, boost::unordered::detail::emplace_args1<
                boost::unordered::detail::please_ignore_this_overload> const&)
        {
            BOOST_ASSERT(false);
            return iterator();
        }
#   else
        iterator emplace(
                boost::unordered::detail::please_ignore_this_overload const&)
        {
            BOOST_ASSERT(false);
            return iterator();
        }

        iterator emplace_hint(c_iterator,
                boost::unordered::detail::please_ignore_this_overload const&)
        {
            BOOST_ASSERT(false);
            return iterator();
        }
#   endif
#endif

        template <BOOST_UNORDERED_EMPLACE_TEMPLATE>
        iterator emplace(BOOST_UNORDERED_EMPLACE_ARGS)
        {
            return iterator(emplace_impl(
                boost::unordered::detail::func::construct_node_from_args(
                    this->node_alloc(), BOOST_UNORDERED_EMPLACE_FORWARD)));
        }

        template <BOOST_UNORDERED_EMPLACE_TEMPLATE>
        iterator emplace_hint(c_iterator hint, BOOST_UNORDERED_EMPLACE_ARGS)
        {
            return iterator(emplace_hint_impl(hint,
                boost::unordered::detail::func::construct_node_from_args(
                    this->node_alloc(), BOOST_UNORDERED_EMPLACE_FORWARD)));
        }

        iterator emplace_impl(node_pointer n)
        {
            node_tmp a(n, this->node_alloc());
            key_type const& k = this->get_key(a.node_->value());
            std::size_t key_hash = this->hash(k);
            node_pointer position = this->find_node(key_hash, k);
            this->reserve_for_insert(this->size_ + 1);
            return iterator(this->add_node(a.release(), key_hash, position));
        }

        iterator emplace_hint_impl(c_iterator hint, node_pointer n)
        {
            node_tmp a(n, this->node_alloc());
            key_type const& k = this->get_key(a.node_->value());
            if (hint.node_ && this->key_eq()(k, this->get_key(*hint))) {
                this->reserve_for_insert(this->size_ + 1);
                return iterator(this->add_using_hint(a.release(), hint.node_));
            }
            else {
                std::size_t key_hash = this->hash(k);
                node_pointer position = this->find_node(key_hash, k);
                this->reserve_for_insert(this->size_ + 1);
                return iterator(this->add_node(a.release(), key_hash, position));
            }
        }

        void emplace_impl_no_rehash(node_pointer n)
        {
            node_tmp a(n, this->node_alloc());
            key_type const& k = this->get_key(a.node_->value());
            std::size_t key_hash = this->hash(k);
            node_pointer position = this->find_node(key_hash, k);
            this->add_node(a.release(), key_hash, position);
        }

        ////////////////////////////////////////////////////////////////////////
        // Insert range methods

        // if hash function throws, or inserting > 1 element, basic exception
        // safety. Strong otherwise
        template <class I>
        void insert_range(I i, I j, typename
            boost::unordered::detail::enable_if_forward<I, void*>::type = 0)
        {
            if(i == j) return;

            std::size_t distance = static_cast<std::size_t>(std::distance(i, j));
            if(distance == 1) {
                emplace_impl(
                    boost::unordered::detail::func::construct_node(
                        this->node_alloc(), *i));
            }
            else {
                // Only require basic exception safety here
                this->reserve_for_insert(this->size_ + distance);

                for (; i != j; ++i) {
                    emplace_impl_no_rehash(
                        boost::unordered::detail::func::construct_node(
                            this->node_alloc(), *i));
                }
            }
        }

        template <class I>
        void insert_range(I i, I j, typename
            boost::unordered::detail::disable_if_forward<I, void*>::type = 0)
        {
            for (; i != j; ++i) {
                emplace_impl(
                    boost::unordered::detail::func::construct_node(
                        this->node_alloc(), *i));
            }
        }

        ////////////////////////////////////////////////////////////////////////
        // Erase
        //
        // no throw

        std::size_t erase_key(key_type const& k)
        {
            if(!this->size_) return 0;

            std::size_t key_hash = this->hash(k);
            std::size_t bucket_index = this->hash_to_bucket(key_hash);
            link_pointer prev = this->get_previous_start(bucket_index);
            if (!prev) return 0;

            node_pointer first_node;

            for (;;)
            {
                if (!prev->next_) return 0;
                first_node = next_node(prev);
                std::size_t node_hash = first_node->hash_;
                if (this->hash_to_bucket(node_hash) != bucket_index)
                    return 0;
                if (node_hash == key_hash &&
                    this->key_eq()(k, this->get_key(first_node->value())))
                    break;
                prev = first_node->group_prev_;
            }

            link_pointer end = first_node->group_prev_->next_;

            std::size_t deleted_count = this->delete_nodes(prev, end);
            this->fix_bucket(bucket_index, prev);
            return deleted_count;
        }

        iterator erase(c_iterator r)
        {
            BOOST_ASSERT(r.node_);
            node_pointer next = next_node(r.node_);
            erase_nodes(r.node_, next);
            return iterator(next);
        }

        iterator erase_range(c_iterator r1, c_iterator r2)
        {
            if (r1 == r2) return iterator(r2.node_);
            erase_nodes(r1.node_, r2.node_);
            return iterator(r2.node_);
        }

        link_pointer erase_nodes(node_pointer i, node_pointer j)
        {
            std::size_t bucket_index = this->hash_to_bucket(i->hash_);

            // Split the groups containing 'i' and 'j'.
            // And get the pointer to the node before i while
            // we're at it.
            link_pointer prev = split_groups(i, j);

            // If we don't have a 'prev' it means that i is at the
            // beginning of a block, so search through the blocks in the
            // same bucket.
            if (!prev) {
                prev = this->get_previous_start(bucket_index);
                while (prev->next_ != i)
                    prev = next_node(prev)->group_prev_;
            }

            // Delete the nodes.
            do {
                link_pointer group_end = next_group(next_node(prev));
                this->delete_nodes(prev, group_end);
                bucket_index = this->fix_bucket(bucket_index, prev);
            } while(prev->next_ != j);

            return prev;
        }

        static link_pointer split_groups(node_pointer i, node_pointer j)
        {
            node_pointer prev = i->group_prev_;
            if (prev->next_ != i) prev = node_pointer();

            if (j) {
                node_pointer first = j;
                while (first != i && first->group_prev_->next_ == first) {
                    first = first->group_prev_;
                }

                boost::swap(first->group_prev_, j->group_prev_);
                if (first == i) return prev;
            }

            if (prev) {
                node_pointer first = prev;
                while (first->group_prev_->next_ == first) {
                    first = first->group_prev_;
                }
                boost::swap(first->group_prev_, i->group_prev_);
            }

            return prev;
        }

        ////////////////////////////////////////////////////////////////////////
        // fill_buckets

        void copy_buckets(table const& src) {
            this->create_buckets(this->bucket_count_);

            for (node_pointer n = src.begin(); n;) {
                std::size_t key_hash = n->hash_;
                node_pointer group_end(next_group(n));
                node_pointer pos = this->add_node(
                    boost::unordered::detail::func::construct_node(
                        this->node_alloc(), n->value()), key_hash, node_pointer());
                for (n = next_node(n); n != group_end; n = next_node(n))
                {
                    this->add_node(
                        boost::unordered::detail::func::construct_node(
                            this->node_alloc(), n->value()), key_hash, pos);
                }
            }
        }

        void move_buckets(table const& src) {
            this->create_buckets(this->bucket_count_);

            for (node_pointer n = src.begin(); n;) {
                std::size_t key_hash = n->hash_;
                node_pointer group_end(next_group(n));
                node_pointer pos = this->add_node(
                    boost::unordered::detail::func::construct_node(
                        this->node_alloc(), boost::move(n->value())), key_hash, node_pointer());
                for (n = next_node(n); n != group_end; n = next_node(n))
                {
                    this->add_node(
                        boost::unordered::detail::func::construct_node(
                            this->node_alloc(), boost::move(n->value())), key_hash, pos);
                }
            }
        }

        void assign_buckets(table const& src) {
            node_holder<node_allocator> holder(*this);
            for (node_pointer n = src.begin(); n;) {
                std::size_t key_hash = n->hash_;
                node_pointer group_end(next_group(n));
                node_pointer pos = this->add_node(holder.copy_of(n->value()), key_hash, node_pointer());
                for (n = next_node(n); n != group_end; n = next_node(n))
                {
                    this->add_node(holder.copy_of(n->value()), key_hash, pos);
                }
            }
        }

        void move_assign_buckets(table& src) {
            node_holder<node_allocator> holder(*this);
            for (node_pointer n = src.begin(); n;) {
                std::size_t key_hash = n->hash_;
                node_pointer group_end(next_group(n));
                node_pointer pos = this->add_node(holder.move_copy_of(n->value()), key_hash, node_pointer());
                for (n = next_node(n); n != group_end; n = next_node(n))
                {
                    this->add_node(holder.move_copy_of(n->value()), key_hash, pos);
                }
            }
        }

        // strong otherwise exception safety
        void rehash_impl(std::size_t num_buckets)
        {
            BOOST_ASSERT(this->buckets_);

            this->create_buckets(num_buckets);
            link_pointer prev = this->get_previous_start();
            while (prev->next_)
                prev = place_in_bucket(*this, prev, next_node(prev)->group_prev_);
        }

        // Iterate through the nodes placing them in the correct buckets.
        // pre: prev->next_ is not null.
        static link_pointer place_in_bucket(table& dst,
                link_pointer prev, node_pointer end)
        {
            bucket_pointer b = dst.get_bucket(dst.hash_to_bucket(end->hash_));

            if (!b->next_) {
                b->next_ = prev;
                return end;
            }
            else {
                link_pointer next = end->next_;
                end->next_ = b->next_->next_;
                b->next_->next_ = prev->next_;
                prev->next_ = next;
                return prev;
            }
        }
    };
}}}

#endif