Files
boost_unordered/include/boost/unordered/detail/util.hpp
Daniel James dac1dc5837 Unordered: Reorganization to use void pointers and other things.
Helps allocators which can't use incomplete pointers, and avoid using
base pointers where that might not be possible.  And some other
reorganization. Storing arguments to emplace in a structure when
variadic template parameters aren't available. Changed some of the odd
design for working with older compilers.

[SVN r74742]
2011-10-05 19:45:14 +00:00

260 lines
7.4 KiB
C++

// Copyright (C) 2003-2004 Jeremy B. Maitin-Shepard.
// Copyright (C) 2005-2011 Daniel James
// Distributed under the Boost Software License, Version 1.0. (See accompanying
// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
#ifndef BOOST_UNORDERED_DETAIL_UTIL_HPP_INCLUDED
#define BOOST_UNORDERED_DETAIL_UTIL_HPP_INCLUDED
#if defined(_MSC_VER) && (_MSC_VER >= 1020)
# pragma once
#endif
#include <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>
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 {};
////////////////////////////////////////////////////////////////////////////
// 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 \
(5ul)(11ul)(17ul)(29ul)(37ul)(53ul)(67ul)(79ul) \
(97ul)(131ul)(193ul)(257ul)(389ul)(521ul)(769ul) \
(1031ul)(1543ul)(2053ul)(3079ul)(6151ul)(12289ul)(24593ul) \
(49157ul)(98317ul)(196613ul)(393241ul)(786433ul) \
(1572869ul)(3145739ul)(6291469ul)(12582917ul)(25165843ul) \
(50331653ul)(100663319ul)(201326611ul)(402653189ul)(805306457ul) \
(1610612741ul)(3221225473ul)(4294967291ul)
template<class T> struct prime_list_template
{
static std::size_t const value[];
#if !defined(SUNPRO_CC)
static std::ptrdiff_t const length;
#else
static std::ptrdiff_t const length
= BOOST_PP_SEQ_SIZE(BOOST_UNORDERED_PRIMES);
#endif
};
template<class T>
std::size_t const prime_list_template<T>::value[] = {
BOOST_PP_SEQ_ENUM(BOOST_UNORDERED_PRIMES)
};
#if !defined(SUNPRO_CC)
template<class T>
std::ptrdiff_t const prime_list_template<T>::length
= BOOST_PP_SEQ_SIZE(BOOST_UNORDERED_PRIMES);
#endif
#undef BOOST_UNORDERED_PRIMES
typedef prime_list_template<std::size_t> prime_list;
// no throw
inline std::size_t next_prime(std::size_t num) {
std::size_t const* const prime_list_begin = prime_list::value;
std::size_t const* const prime_list_end = prime_list_begin +
prime_list::length;
std::size_t const* bound =
std::lower_bound(prime_list_begin, prime_list_end, num);
if(bound == prime_list_end)
bound--;
return *bound;
}
// no throw
inline std::size_t prev_prime(std::size_t num) {
std::size_t const* const prime_list_begin = prime_list::value;
std::size_t const* const prime_list_end = prime_list_begin +
prime_list::length;
std::size_t const* bound =
std::upper_bound(prime_list_begin,prime_list_end, num);
if(bound != prime_list_begin)
bound--;
return *bound;
}
////////////////////////////////////////////////////////////////////////////
// insert_size/initial_size
#if !defined(BOOST_NO_STD_DISTANCE)
using ::std::distance;
#else
template <class ForwardIterator>
inline std::size_t distance(ForwardIterator i, ForwardIterator j) {
std::size_t x;
std::distance(i, j, x);
return x;
}
#endif
template <class I>
inline typename
::boost::unordered::detail::enable_if_forward<I, std::size_t>::type
insert_size(I i, I j)
{
return std::distance(i, j);
}
template <class I>
inline typename
::boost::unordered::detail::disable_if_forward<I, std::size_t>::type
insert_size(I, I)
{
return 1;
}
template <class I>
inline std::size_t initial_size(I i, I j,
std::size_t num_buckets = ::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<
compressed_base<T, Index>,
uncompressed_base<T, Index>
>
{};
template <typename T1, typename T2>
struct compressed
: private generate_base<T1, 1>::type,
private 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&);
};
}}}
#endif