forked from boostorg/unordered
267 lines
7.6 KiB
C++
267 lines
7.6 KiB
C++
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// Copyright (C) 2003-2004 Jeremy B. Maitin-Shepard.
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// Copyright (C) 2005-2011 Daniel James
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// Distributed under the Boost Software License, Version 1.0. (See accompanying
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// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
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#ifndef BOOST_UNORDERED_DETAIL_UTIL_HPP_INCLUDED
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#define BOOST_UNORDERED_DETAIL_UTIL_HPP_INCLUDED
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#include <boost/config.hpp>
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#if defined(BOOST_HAS_PRAGMA_ONCE)
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#pragma once
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#endif
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#include <boost/type_traits/is_convertible.hpp>
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#include <boost/type_traits/is_empty.hpp>
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#include <boost/iterator/iterator_categories.hpp>
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#include <boost/utility/enable_if.hpp>
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#include <boost/detail/select_type.hpp>
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#include <boost/move/move.hpp>
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#include <boost/preprocessor/seq/size.hpp>
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#include <boost/preprocessor/seq/enum.hpp>
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#include <boost/swap.hpp>
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namespace boost { namespace unordered { namespace detail {
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static const float minimum_max_load_factor = 1e-3f;
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static const std::size_t default_bucket_count = 11;
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struct move_tag {};
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struct empty_emplace {};
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namespace func {
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template <class T>
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inline void ignore_unused_variable_warning(T const&) {}
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}
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////////////////////////////////////////////////////////////////////////////
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// iterator SFINAE
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template <typename I>
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struct is_forward :
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boost::is_convertible<
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typename boost::iterator_traversal<I>::type,
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boost::forward_traversal_tag>
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{};
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template <typename I, typename ReturnType>
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struct enable_if_forward :
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boost::enable_if_c<
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boost::unordered::detail::is_forward<I>::value,
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ReturnType>
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{};
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template <typename I, typename ReturnType>
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struct disable_if_forward :
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boost::disable_if_c<
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boost::unordered::detail::is_forward<I>::value,
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ReturnType>
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{};
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////////////////////////////////////////////////////////////////////////////
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// primes
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#define BOOST_UNORDERED_PRIMES \
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(17ul)(29ul)(37ul)(53ul)(67ul)(79ul) \
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(97ul)(131ul)(193ul)(257ul)(389ul)(521ul)(769ul) \
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(1031ul)(1543ul)(2053ul)(3079ul)(6151ul)(12289ul)(24593ul) \
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(49157ul)(98317ul)(196613ul)(393241ul)(786433ul) \
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(1572869ul)(3145739ul)(6291469ul)(12582917ul)(25165843ul) \
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(50331653ul)(100663319ul)(201326611ul)(402653189ul)(805306457ul) \
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(1610612741ul)(3221225473ul)(4294967291ul)
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template<class T> struct prime_list_template
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{
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static std::size_t const value[];
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#if !defined(SUNPRO_CC)
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static std::ptrdiff_t const length;
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#else
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static std::ptrdiff_t const length
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= BOOST_PP_SEQ_SIZE(BOOST_UNORDERED_PRIMES);
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#endif
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};
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template<class T>
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std::size_t const prime_list_template<T>::value[] = {
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BOOST_PP_SEQ_ENUM(BOOST_UNORDERED_PRIMES)
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};
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#if !defined(SUNPRO_CC)
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template<class T>
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std::ptrdiff_t const prime_list_template<T>::length
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= BOOST_PP_SEQ_SIZE(BOOST_UNORDERED_PRIMES);
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#endif
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#undef BOOST_UNORDERED_PRIMES
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typedef prime_list_template<std::size_t> prime_list;
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// no throw
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inline std::size_t next_prime(std::size_t num) {
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std::size_t const* const prime_list_begin = prime_list::value;
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std::size_t const* const prime_list_end = prime_list_begin +
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prime_list::length;
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std::size_t const* bound =
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std::lower_bound(prime_list_begin, prime_list_end, num);
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if(bound == prime_list_end)
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bound--;
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return *bound;
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}
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// no throw
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inline std::size_t prev_prime(std::size_t num) {
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std::size_t const* const prime_list_begin = prime_list::value;
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std::size_t const* const prime_list_end = prime_list_begin +
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prime_list::length;
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std::size_t const* bound =
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std::upper_bound(prime_list_begin,prime_list_end, num);
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if(bound != prime_list_begin)
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bound--;
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return *bound;
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}
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////////////////////////////////////////////////////////////////////////////
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// insert_size/initial_size
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#if !defined(BOOST_NO_STD_DISTANCE)
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using ::std::distance;
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#else
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template <class ForwardIterator>
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inline std::size_t distance(ForwardIterator i, ForwardIterator j) {
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std::size_t x;
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std::distance(i, j, x);
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return x;
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}
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#endif
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template <class I>
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inline typename
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boost::unordered::detail::enable_if_forward<I, std::size_t>::type
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insert_size(I i, I j)
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{
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return std::distance(i, j);
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}
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template <class I>
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inline typename
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boost::unordered::detail::disable_if_forward<I, std::size_t>::type
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insert_size(I, I)
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{
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return 1;
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}
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template <class I>
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inline std::size_t initial_size(I i, I j,
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std::size_t num_buckets =
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boost::unordered::detail::default_bucket_count)
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{
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// TODO: Why +1?
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return (std::max)(
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boost::unordered::detail::insert_size(i, j) + 1,
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num_buckets);
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}
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////////////////////////////////////////////////////////////////////////////
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// compressed
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template <typename T, int Index>
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struct compressed_base : private T
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{
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compressed_base(T const& x) : T(x) {}
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compressed_base(T& x, move_tag) : T(boost::move(x)) {}
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T& get() { return *this; }
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T const& get() const { return *this; }
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};
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template <typename T, int Index>
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struct uncompressed_base
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{
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uncompressed_base(T const& x) : value_(x) {}
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uncompressed_base(T& x, move_tag) : value_(boost::move(x)) {}
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T& get() { return value_; }
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T const& get() const { return value_; }
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private:
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T value_;
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};
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template <typename T, int Index>
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struct generate_base
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: boost::detail::if_true<
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boost::is_empty<T>::value
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>:: BOOST_NESTED_TEMPLATE then<
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boost::unordered::detail::compressed_base<T, Index>,
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boost::unordered::detail::uncompressed_base<T, Index>
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>
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{};
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template <typename T1, typename T2>
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struct compressed
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: private boost::unordered::detail::generate_base<T1, 1>::type,
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private boost::unordered::detail::generate_base<T2, 2>::type
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{
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typedef typename generate_base<T1, 1>::type base1;
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typedef typename generate_base<T2, 2>::type base2;
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typedef T1 first_type;
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typedef T2 second_type;
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first_type& first() {
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return static_cast<base1*>(this)->get();
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}
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first_type const& first() const {
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return static_cast<base1 const*>(this)->get();
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}
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second_type& second() {
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return static_cast<base2*>(this)->get();
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}
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second_type const& second() const {
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return static_cast<base2 const*>(this)->get();
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}
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template <typename First, typename Second>
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compressed(First const& x1, Second const& x2)
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: base1(x1), base2(x2) {}
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compressed(compressed const& x)
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: base1(x.first()), base2(x.second()) {}
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compressed(compressed& x, move_tag m)
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: base1(x.first(), m), base2(x.second(), m) {}
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void assign(compressed const& x)
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{
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first() = x.first();
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second() = x.second();
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}
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void move_assign(compressed& x)
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{
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first() = boost::move(x.first());
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second() = boost::move(x.second());
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}
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void swap(compressed& x)
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{
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boost::swap(first(), x.first());
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boost::swap(second(), x.second());
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}
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private:
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// Prevent assignment just to make use of assign or
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// move_assign explicit.
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compressed& operator=(compressed const&);
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};
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}}}
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#endif
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