mirror of
https://github.com/boostorg/iterator.git
synced 2025-05-10 07:33:53 +00:00
Removed MPL usage from facade_iterator_category.hpp.
This commit is contained in:
Andrey Semashev
parent
5f713e9b14
commit
d8ce9ddfc7
@ -2,24 +2,17 @@
|
||||
// subject to 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 FACADE_ITERATOR_CATEGORY_DWA20031118_HPP
|
||||
# define FACADE_ITERATOR_CATEGORY_DWA20031118_HPP
|
||||
#define FACADE_ITERATOR_CATEGORY_DWA20031118_HPP
|
||||
|
||||
# include <boost/core/use_default.hpp>
|
||||
#include <iterator>
|
||||
#include <type_traits>
|
||||
|
||||
# include <boost/iterator/iterator_categories.hpp>
|
||||
#include <boost/mp11/utility.hpp>
|
||||
|
||||
# include <boost/mpl/eval_if.hpp>
|
||||
# include <boost/mpl/identity.hpp>
|
||||
|
||||
# include <type_traits>
|
||||
|
||||
# include <boost/iterator/detail/type_traits/conjunction.hpp>
|
||||
# include <boost/iterator/detail/type_traits/disjunction.hpp>
|
||||
# include <boost/iterator/detail/config_def.hpp> // try to keep this last
|
||||
|
||||
# ifdef BOOST_ITERATOR_REF_CONSTNESS_KILLS_WRITABILITY
|
||||
# include <boost/detail/indirect_traits.hpp>
|
||||
# endif
|
||||
#include <boost/iterator/iterator_categories.hpp>
|
||||
#include <boost/iterator/detail/type_traits/conjunction.hpp>
|
||||
#include <boost/iterator/detail/type_traits/disjunction.hpp>
|
||||
#include <boost/iterator/detail/config_def.hpp> // try to keep this last
|
||||
|
||||
//
|
||||
// iterator_category deduction for iterator_facade
|
||||
@ -27,13 +20,10 @@
|
||||
|
||||
namespace boost {
|
||||
namespace iterators {
|
||||
|
||||
using boost::use_default;
|
||||
|
||||
namespace detail {
|
||||
|
||||
struct input_output_iterator_tag
|
||||
: std::input_iterator_tag
|
||||
struct input_output_iterator_tag :
|
||||
public std::input_iterator_tag
|
||||
{
|
||||
// Using inheritance for only input_iterator_tag helps to avoid
|
||||
// ambiguities when a stdlib implementation dispatches on a
|
||||
@ -47,21 +37,35 @@ struct input_output_iterator_tag
|
||||
}
|
||||
};
|
||||
|
||||
#ifdef BOOST_ITERATOR_REF_CONSTNESS_KILLS_WRITABILITY
|
||||
|
||||
template< typename T >
|
||||
struct is_const_lvalue_reference :
|
||||
public std::false_type
|
||||
{};
|
||||
|
||||
template< typename T >
|
||||
struct is_const_lvalue_reference< T const& > :
|
||||
public std::true_type
|
||||
{};
|
||||
|
||||
#endif // BOOST_ITERATOR_REF_CONSTNESS_KILLS_WRITABILITY
|
||||
|
||||
//
|
||||
// True iff the user has explicitly disabled writability of this
|
||||
// iterator. Pass the iterator_facade's Value parameter and its
|
||||
// nested ::reference type.
|
||||
//
|
||||
template <class ValueParam, class Reference>
|
||||
struct iterator_writability_disabled
|
||||
template< typename ValueParam, typename Reference >
|
||||
struct iterator_writability_disabled :
|
||||
# ifdef BOOST_ITERATOR_REF_CONSTNESS_KILLS_WRITABILITY // Adding Thomas' logic?
|
||||
: disjunction<
|
||||
std::is_const<Reference>
|
||||
, std::integral_constant<bool, boost::detail::indirect_traits::is_reference_to_const<Reference>::value>
|
||||
, std::is_const<ValueParam>
|
||||
public disjunction<
|
||||
is_const_lvalue_reference<Reference>,
|
||||
std::is_const<Reference>,
|
||||
std::is_const<ValueParam>
|
||||
>
|
||||
# else
|
||||
: std::is_const<ValueParam>
|
||||
public std::is_const<ValueParam>
|
||||
# endif
|
||||
{};
|
||||
|
||||
@ -74,69 +78,68 @@ struct iterator_writability_disabled
|
||||
// to output_iterator_tag.
|
||||
//
|
||||
// Change at: https://svn.boost.org/trac/boost/changeset/21683
|
||||
template <class Traversal, class ValueParam, class Reference>
|
||||
template< typename Traversal, typename ValueParam, typename Reference >
|
||||
struct iterator_facade_default_category
|
||||
: mpl::eval_if<
|
||||
{
|
||||
using type = typename mp11::mp_if<
|
||||
detail::conjunction<
|
||||
std::is_reference<Reference>
|
||||
, std::is_convertible<Traversal,forward_traversal_tag>
|
||||
>
|
||||
, mpl::eval_if<
|
||||
std::is_convertible<Traversal,random_access_traversal_tag>
|
||||
, mpl::identity<std::random_access_iterator_tag>
|
||||
, std::conditional<
|
||||
std::is_convertible<Traversal,bidirectional_traversal_tag>::value
|
||||
, std::bidirectional_iterator_tag
|
||||
, std::forward_iterator_tag
|
||||
>
|
||||
>
|
||||
, mpl::eval_if<
|
||||
std::is_reference<Reference>,
|
||||
std::is_convertible<Traversal, forward_traversal_tag>
|
||||
>,
|
||||
mp11::mp_defer<
|
||||
mp11::mp_cond,
|
||||
std::is_convertible<Traversal, random_access_traversal_tag>, std::random_access_iterator_tag,
|
||||
std::is_convertible<Traversal, bidirectional_traversal_tag>, std::bidirectional_iterator_tag,
|
||||
std::true_type, std::forward_iterator_tag
|
||||
>,
|
||||
mp11::mp_defer<
|
||||
mp11::mp_if,
|
||||
detail::conjunction<
|
||||
std::is_convertible<Traversal, single_pass_traversal_tag>
|
||||
std::is_convertible<Traversal, single_pass_traversal_tag>,
|
||||
|
||||
// check for readability
|
||||
, std::is_convertible<Reference, ValueParam>
|
||||
std::is_convertible<Reference, ValueParam>
|
||||
>,
|
||||
std::input_iterator_tag,
|
||||
Traversal
|
||||
>
|
||||
, mpl::identity<std::input_iterator_tag>
|
||||
, mpl::identity<Traversal>
|
||||
>
|
||||
>
|
||||
{
|
||||
>::type;
|
||||
};
|
||||
|
||||
template< typename Traversal, typename ValueParam, typename Reference >
|
||||
using iterator_facade_default_category_t = typename iterator_facade_default_category<Traversal, ValueParam, Reference>::type;
|
||||
|
||||
// True iff T is convertible to an old-style iterator category.
|
||||
template <class T>
|
||||
struct is_iterator_category
|
||||
: disjunction<
|
||||
std::is_convertible<T,std::input_iterator_tag>
|
||||
, std::is_convertible<T,std::output_iterator_tag>
|
||||
template< typename T >
|
||||
struct is_iterator_category :
|
||||
public disjunction<
|
||||
std::is_convertible<T, std::input_iterator_tag>,
|
||||
std::is_convertible<T, std::output_iterator_tag>
|
||||
>
|
||||
{
|
||||
};
|
||||
|
||||
template <class T>
|
||||
struct is_iterator_traversal
|
||||
: std::is_convertible<T,incrementable_traversal_tag>
|
||||
{};
|
||||
|
||||
template< typename T >
|
||||
struct is_iterator_traversal :
|
||||
public std::is_convertible<T, incrementable_traversal_tag>
|
||||
{};
|
||||
|
||||
|
||||
//
|
||||
// A composite iterator_category tag convertible to Category (a pure
|
||||
// old-style category) and Traversal (a pure traversal tag).
|
||||
// Traversal must be a strict increase of the traversal power given by
|
||||
// Category.
|
||||
//
|
||||
template <class Category, class Traversal>
|
||||
struct iterator_category_with_traversal
|
||||
: Category, Traversal
|
||||
template< typename Category, typename Traversal >
|
||||
struct iterator_category_with_traversal :
|
||||
public Category,
|
||||
public Traversal
|
||||
{
|
||||
// Make sure this isn't used to build any categories where
|
||||
// convertibility to Traversal is redundant. Should just use the
|
||||
// Category element in that case.
|
||||
static_assert(
|
||||
!std::is_convertible<
|
||||
typename iterator_category_to_traversal<Category>::type
|
||||
, Traversal
|
||||
>::value,
|
||||
!std::is_convertible<iterator_category_to_traversal_t<Category>, Traversal>::value,
|
||||
"Category transformed to corresponding traversal must be convertible to Traversal."
|
||||
);
|
||||
|
||||
@ -148,40 +151,41 @@ struct iterator_category_with_traversal
|
||||
|
||||
// Computes an iterator_category tag whose traversal is Traversal and
|
||||
// which is appropriate for an iterator
|
||||
template <class Traversal, class ValueParam, class Reference>
|
||||
template< typename Traversal, typename ValueParam, typename Reference >
|
||||
struct facade_iterator_category_impl
|
||||
{
|
||||
static_assert(!is_iterator_category<Traversal>::value, "Traversal must not be an STL iterator category.");
|
||||
|
||||
typedef typename iterator_facade_default_category<
|
||||
Traversal,ValueParam,Reference
|
||||
>::type category;
|
||||
using category = iterator_facade_default_category_t<Traversal, ValueParam, Reference>;
|
||||
|
||||
typedef typename std::conditional<
|
||||
using type = typename std::conditional<
|
||||
std::is_same<
|
||||
Traversal
|
||||
, typename iterator_category_to_traversal<category>::type
|
||||
>::value
|
||||
, category
|
||||
, iterator_category_with_traversal<category,Traversal>
|
||||
>::type type;
|
||||
Traversal,
|
||||
typename iterator_category_to_traversal<category>::type
|
||||
>::value,
|
||||
category,
|
||||
iterator_category_with_traversal<category, Traversal>
|
||||
>::type;
|
||||
};
|
||||
|
||||
template< typename Traversal, typename ValueParam, typename Reference >
|
||||
using facade_iterator_category_impl_t = typename facade_iterator_category_impl<Traversal, ValueParam, Reference>::type;
|
||||
|
||||
//
|
||||
// Compute an iterator_category for iterator_facade
|
||||
//
|
||||
template <class CategoryOrTraversal, class ValueParam, class Reference>
|
||||
template< typename CategoryOrTraversal, typename ValueParam, typename Reference >
|
||||
struct facade_iterator_category
|
||||
: mpl::eval_if<
|
||||
is_iterator_category<CategoryOrTraversal>
|
||||
, mpl::identity<CategoryOrTraversal> // old-style categories are fine as-is
|
||||
, facade_iterator_category_impl<CategoryOrTraversal,ValueParam,Reference>
|
||||
>
|
||||
{
|
||||
using type = mp11::mp_eval_if<
|
||||
is_iterator_category<CategoryOrTraversal>,
|
||||
CategoryOrTraversal, // old-style categories are fine as-is
|
||||
facade_iterator_category_impl_t, CategoryOrTraversal, ValueParam, Reference
|
||||
>;
|
||||
};
|
||||
|
||||
}}} // namespace boost::iterators::detail
|
||||
|
||||
# include <boost/iterator/detail/config_undef.hpp>
|
||||
#include <boost/iterator/detail/config_undef.hpp>
|
||||
|
||||
#endif // FACADE_ITERATOR_CATEGORY_DWA20031118_HPP
|
||||
|
||||
Loading…
x
Reference in New Issue
Block a user