boostorg/iterator
1
0
Fork 1
mirror of https://github.com/boostorg/iterator.git synced 2025-07-30 04:47:20 +02:00
Code Issues Packages Projects Releases Wiki Activity

Slightly optimized iterator_facade_default_category compilation speed.

Browse Source
This commit is contained in:
Andrey Semashev
2025-01-31 00:34:06 +03:00
parent 5aa1c9fef3
commit 4f5f61e37b
1 changed files with 46 additions and 43 deletions
Download Patch File Download Diff File Expand all files Collapse all files

89
include/boost/iterator/detail/facade_iterator_category.hpp
View File

@ -44,17 +44,25 @@ struct is_const_lvalue_reference< T const& > :
template< typename ValueParam, typename Reference > template< typename ValueParam, typename Reference >
struct iterator_writability_disabled : struct iterator_writability_disabled :
# ifdef BOOST_ITERATOR_REF_CONSTNESS_KILLS_WRITABILITY // Adding Thomas' logic? # ifdef BOOST_ITERATOR_REF_CONSTNESS_KILLS_WRITABILITY // Adding Thomas' logic?
public disjunction< public detail::disjunction<
is_const_lvalue_reference<Reference>, detail::is_const_lvalue_reference< Reference >,
std::is_const<Reference>, std::is_const< Reference >,
std::is_const<ValueParam> std::is_const< ValueParam >
> >
# else # else
public std::is_const<ValueParam> public std::is_const< ValueParam >
# endif # endif
{}; {};
template< typename Traversal, typename ValueParam, typename Reference >
using is_traversal_of_input_iterator = detail::conjunction<
std::is_convertible< Traversal, single_pass_traversal_tag >,
// check for readability
std::is_convertible< Reference, ValueParam >
>;
// //
// Convert an iterator_facade's traversal category, Value parameter, // Convert an iterator_facade's traversal category, Value parameter,
// and ::reference type to an appropriate old-style category. // and ::reference type to an appropriate old-style category.
@ -66,46 +74,41 @@ struct iterator_writability_disabled :
template< typename Traversal, typename ValueParam, typename Reference > template< typename Traversal, typename ValueParam, typename Reference >
struct iterator_facade_default_category struct iterator_facade_default_category
{ {
using type = typename mp11::mp_if< using type = typename std::conditional<
detail::conjunction< detail::is_traversal_of_input_iterator< Traversal, ValueParam, Reference >::value,
std::is_reference<Reference>, std::input_iterator_tag,
std::is_convertible<Traversal, forward_traversal_tag> Traversal
>,
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>,
// check for readability
std::is_convertible<Reference, ValueParam>
>,
std::input_iterator_tag,
Traversal
>
>::type; >::type;
}; };
// Specialization for the (typical) case when the reference type is an actual reference
template< typename Traversal, typename ValueParam, typename Referenced >
struct iterator_facade_default_category< Traversal, ValueParam, Referenced& >
{
using type = 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::is_convertible< Traversal, forward_traversal_tag >, std::forward_iterator_tag,
detail::is_traversal_of_input_iterator< Traversal, ValueParam, Referenced& >, std::input_iterator_tag,
std::true_type, Traversal
>;
};
template< typename Traversal, typename ValueParam, typename Reference > template< typename Traversal, typename ValueParam, typename Reference >
using iterator_facade_default_category_t = typename iterator_facade_default_category<Traversal, ValueParam, Reference>::type; 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. // True iff T is convertible to an old-style iterator category.
template< typename T > template< typename T >
struct is_iterator_category : struct is_iterator_category :
public disjunction< public detail::disjunction<
std::is_convertible<T, std::input_iterator_tag>, std::is_convertible< T, std::input_iterator_tag >,
std::is_convertible<T, std::output_iterator_tag> std::is_convertible< T, std::output_iterator_tag >
> >
{}; {};
template< typename T > template< typename T >
struct is_iterator_traversal : struct is_iterator_traversal :
public std::is_convertible<T, incrementable_traversal_tag> public std::is_convertible< T, incrementable_traversal_tag >
{}; {};
@ -124,14 +127,14 @@ struct iterator_category_with_traversal :
// convertibility to Traversal is redundant. Should just use the // convertibility to Traversal is redundant. Should just use the
// Category element in that case. // Category element in that case.
static_assert( static_assert(
!std::is_convertible<iterator_category_to_traversal_t<Category>, Traversal>::value, !std::is_convertible< iterator_category_to_traversal_t< Category >, Traversal >::value,
"Category transformed to corresponding traversal must be convertible to Traversal." "Category transformed to corresponding traversal must be convertible to Traversal."
); );
static_assert(is_iterator_category<Category>::value, "Category must be an STL iterator category."); static_assert(is_iterator_category< Category >::value, "Category must be an STL iterator category.");
static_assert(!is_iterator_category<Traversal>::value, "Traversal must not be an STL iterator category."); static_assert(!is_iterator_category< Traversal >::value, "Traversal must not be an STL iterator category.");
static_assert(!is_iterator_traversal<Category>::value, "Category must not be a traversal tag."); static_assert(!is_iterator_traversal< Category >::value, "Category must not be a traversal tag.");
static_assert(is_iterator_traversal<Traversal>::value, "Traversal must be a traversal tag."); static_assert(is_iterator_traversal< Traversal >::value, "Traversal must be a traversal tag.");
}; };
// Computes an iterator_category tag whose traversal is Traversal and // Computes an iterator_category tag whose traversal is Traversal and
@ -139,22 +142,22 @@ struct iterator_category_with_traversal :
template< typename Traversal, typename ValueParam, typename Reference > template< typename Traversal, typename ValueParam, typename Reference >
struct facade_iterator_category_impl struct facade_iterator_category_impl
{ {
static_assert(!is_iterator_category<Traversal>::value, "Traversal must not be an STL iterator category."); static_assert(!is_iterator_category< Traversal >::value, "Traversal must not be an STL iterator category.");
using category = iterator_facade_default_category_t<Traversal, ValueParam, Reference>; using category = iterator_facade_default_category_t< Traversal, ValueParam, Reference >;
using type = typename std::conditional< using type = typename std::conditional<
std::is_same< std::is_same<
Traversal, Traversal,
typename iterator_category_to_traversal<category>::type typename iterator_category_to_traversal< category >::type
>::value, >::value,
category, category,
iterator_category_with_traversal<category, Traversal> iterator_category_with_traversal< category, Traversal >
>::type; >::type;
}; };
template< typename Traversal, typename ValueParam, typename Reference > template< typename Traversal, typename ValueParam, typename Reference >
using facade_iterator_category_impl_t = typename facade_iterator_category_impl<Traversal, ValueParam, Reference>::type; using facade_iterator_category_impl_t = typename facade_iterator_category_impl< Traversal, ValueParam, Reference >::type;
// //
// Compute an iterator_category for iterator_facade // Compute an iterator_category for iterator_facade
@ -163,7 +166,7 @@ template< typename CategoryOrTraversal, typename ValueParam, typename Reference
struct facade_iterator_category struct facade_iterator_category
{ {
using type = mp11::mp_eval_if< using type = mp11::mp_eval_if<
is_iterator_category<CategoryOrTraversal>, is_iterator_category< CategoryOrTraversal >,
CategoryOrTraversal, // old-style categories are fine as-is CategoryOrTraversal, // old-style categories are fine as-is
facade_iterator_category_impl_t, CategoryOrTraversal, ValueParam, Reference facade_iterator_category_impl_t, CategoryOrTraversal, ValueParam, Reference
>; >;