// Copyright (C) 2019 T. Zachary Laine
//
// 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_STL_INTERFACES_ITERATOR_INTERFACE_HPP
#define BOOST_STL_INTERFACES_ITERATOR_INTERFACE_HPP
#include <boost/stl_interfaces/fwd.hpp>
#include <utility>
#include <type_traits>
#if defined(__cpp_lib_three_way_comparison)
#include <compare>
#endif
namespace boost { namespace stl_interfaces {
/** A type for granting access to the private members of an iterator
derived from `iterator_interface`. */
struct access
{
#ifndef BOOST_STL_INTERFACES_DOXYGEN
template<typename D>
static constexpr auto base(D & d) noexcept
-> decltype(d.base_reference())
{
return d.base_reference();
}
template<typename D>
static constexpr auto base(D const & d) noexcept
-> decltype(d.base_reference())
{
return d.base_reference();
}
#endif
};
/** The return type of `operator->()` in a proxy iterator.
This template is used as the default `Pointer` template parameter in
the `proxy_iterator_interface` template alias. Note that the use of
this template implies a copy or move of the underlying object of type
`T`. */
template<typename T>
#if defined(BOOST_STL_INTERFACES_DOXYGEN) || BOOST_STL_INTERFACES_USE_CONCEPTS
// clang-format off
requires std::is_object_v<T>
#endif
struct proxy_arrow_result
// clang-format on
{
constexpr proxy_arrow_result(T const & value) noexcept(
noexcept(T(value))) :
value_(value)
{}
constexpr proxy_arrow_result(T && value) noexcept(
noexcept(T(std::move(value)))) :
value_(std::move(value))
{}
constexpr T const * operator->() const noexcept { return &value_; }
constexpr T * operator->() noexcept { return &value_; }
private:
T value_;
};
namespace detail {
template<typename Pointer, typename Reference, typename T>
auto make_pointer(
T && value,
std::enable_if_t<
std::is_pointer<Pointer>::value &&
std::is_reference<Reference>::value,
int> = 0) -> decltype(std::addressof(value))
{
return std::addressof(value);
}
template<typename Pointer, typename Reference, typename T>
auto make_pointer(
T && value,
std::enable_if_t<
!std::is_pointer<Pointer>::value &&
!std::is_same<Pointer, void>::value &&
std::is_reference<Reference>::value,
int> = 0)
{
return Pointer(std::forward<T>(value));
}
template<typename Pointer, typename IteratorConcept>
struct pointer
{
using type = Pointer;
};
template<typename Pointer>
struct pointer<Pointer, std::output_iterator_tag>
{
using type = void;
};
template<typename Pointer, typename IteratorConcept>
using pointer_t = typename pointer<Pointer, IteratorConcept>::type;
template<typename T, typename U>
using interoperable = std::integral_constant<
bool,
(std::is_convertible<T, U>::value ||
std::is_convertible<U, T>::value)>;
template<typename T, typename U>
using common_t =
std::conditional_t<std::is_convertible<T, U>::value, U, T>;
template<typename T>
using use_base = decltype(access::base(std::declval<T &>()));
template<typename... T>
using void_t = void;
template<
typename AlwaysVoid,
template<class...> class Template,
typename... Args>
struct detector : std::false_type
{
};
template<template<class...> class Template, typename... Args>
struct detector<void_t<Template<Args...>>, Template, Args...>
: std::true_type
{
};
template<
typename T,
typename U,
bool UseBase = detector<void, use_base, T>::value>
struct common_eq
{
static constexpr auto call(T lhs, U rhs)
{
return static_cast<common_t<T, U>>(lhs).derived() ==
static_cast<common_t<T, U>>(rhs).derived();
}
};
template<typename T, typename U>
struct common_eq<T, U, true>
{
static constexpr auto call(T lhs, U rhs)
{
return access::base(lhs) == access::base(rhs);
}
};
template<typename T, typename U>
constexpr auto common_diff(T lhs, U rhs) noexcept(noexcept(
static_cast<common_t<T, U>>(lhs) -
static_cast<common_t<T, U>>(rhs)))
-> decltype(
static_cast<common_t<T, U>>(lhs) -
static_cast<common_t<T, U>>(rhs))
{
return static_cast<common_t<T, U>>(lhs) -
static_cast<common_t<T, U>>(rhs);
}
}
}}
namespace boost { namespace stl_interfaces { BOOST_STL_INTERFACES_NAMESPACE_V1 {
/** A CRTP template that one may derive from to make defining iterators
easier.
The template parameter `D` for `iterator_interface` may be an
incomplete type. Before any member of the resulting specialization of
`iterator_interface` other than special member functions is
referenced, `D` shall be complete, and model
`std::derived_from<iterator_interface<D>>`. */
template<
typename Derived,
typename IteratorConcept,
typename ValueType,
typename Reference = ValueType &,
typename Pointer = ValueType *,
typename DifferenceType = std::ptrdiff_t
#ifndef BOOST_STL_INTERFACES_DOXYGEN
,
typename E = std::enable_if_t<
std::is_class<Derived>::value &&
std::is_same<Derived, std::remove_cv_t<Derived>>::value>
#endif
>
struct iterator_interface;
namespace v1_dtl {
template<typename Iterator, typename = void>
struct ra_iter : std::false_type
{
};
template<typename Iterator>
struct ra_iter<Iterator, void_t<typename Iterator::iterator_concept>>
: std::integral_constant<
bool,
std::is_base_of<
std::random_access_iterator_tag,
typename Iterator::iterator_concept>::value>
{
};
template<typename Iterator, typename DifferenceType, typename = void>
struct plus_eq : std::false_type
{
};
template<typename Iterator, typename DifferenceType>
struct plus_eq<
Iterator,
DifferenceType,
void_t<decltype(
std::declval<Iterator &>() += std::declval<DifferenceType>())>>
: std::true_type
{
};
template<
typename D,
typename IteratorConcept,
typename ValueType,
typename Reference,
typename Pointer,
typename DifferenceType>
void derived_iterator(iterator_interface<
D,
IteratorConcept,
ValueType,
Reference,
Pointer,
DifferenceType> const &);
}
template<
typename Derived,
typename IteratorConcept,
typename ValueType,
typename Reference,
typename Pointer,
typename DifferenceType
#ifndef BOOST_STL_INTERFACES_DOXYGEN
,
typename E
#endif
>
struct iterator_interface
{
#ifndef BOOST_STL_INTERFACES_DOXYGEN
private:
constexpr Derived & derived() noexcept
{
return static_cast<Derived &>(*this);
}
constexpr Derived const & derived() const noexcept
{
return static_cast<Derived const &>(*this);
}
template<typename T, typename U, bool UseBase>
friend struct detail::common_eq;
#endif
public:
using iterator_concept = IteratorConcept;
using iterator_category = iterator_concept;
using value_type = std::remove_const_t<ValueType>;
using reference = Reference;
using pointer = detail::pointer_t<Pointer, iterator_concept>;
using difference_type = DifferenceType;
template<typename D = Derived>
constexpr auto operator*()
noexcept(noexcept(*access::base(std::declval<D &>())))
-> decltype(*access::base(std::declval<D &>()))
{
return *access::base(derived());
}
template<typename D = Derived>
constexpr auto operator*() const
noexcept(noexcept(*access::base(std::declval<D const &>())))
-> decltype(*access::base(std::declval<D const &>()))
{
return *access::base(derived());
}
template<typename D = Derived>
constexpr auto operator->() noexcept(noexcept(
detail::make_pointer<pointer, reference>(*std::declval<D &>())))
-> decltype(
detail::make_pointer<pointer, reference>(*std::declval<D &>()))
{
return detail::make_pointer<pointer, reference>(*derived());
}
template<typename D = Derived>
constexpr auto operator->() const noexcept(noexcept(
detail::make_pointer<pointer, reference>(
*std::declval<D const &>())))
-> decltype(
detail::make_pointer<pointer, reference>(
*std::declval<D const &>()))
{
return detail::make_pointer<pointer, reference>(*derived());
}
template<typename D = Derived>
constexpr auto operator[](difference_type i) const noexcept(noexcept(
D(std::declval<D const &>()),
std::declval<D &>() += i,
*std::declval<D &>()))
-> decltype(std::declval<D &>() += i, *std::declval<D &>())
{
D retval = derived();
retval += i;
return *retval;
}
template<
typename D = Derived,
typename Enable =
std::enable_if_t<!v1_dtl::plus_eq<D, difference_type>::value>>
constexpr auto
operator++() noexcept(noexcept(++access::base(std::declval<D &>())))
-> decltype(
++access::base(std::declval<D &>()), std::declval<D &>())
{
++access::base(derived());
return derived();
}
template<typename D = Derived>
constexpr auto operator++() noexcept(
noexcept(std::declval<D &>() += difference_type(1)))
-> decltype(
std::declval<D &>() += difference_type(1), std::declval<D &>())
{
derived() += difference_type(1);
return derived();
}
template<typename D = Derived>
constexpr auto operator++(int)noexcept(
noexcept(D(std::declval<D &>()), ++std::declval<D &>()))
-> std::remove_reference_t<decltype(
D(std::declval<D &>()),
++std::declval<D &>(),
std::declval<D &>())>
{
D retval = derived();
++derived();
return retval;
}
template<typename D = Derived>
constexpr auto operator+=(difference_type n) noexcept(
noexcept(access::base(std::declval<D &>()) += n))
-> decltype(
access::base(std::declval<D &>()) += n, std::declval<D &>())
{
access::base(derived()) += n;
return derived();
}
template<typename D = Derived>
constexpr auto operator+(difference_type i) const
noexcept(noexcept(D(std::declval<D &>()), std::declval<D &>() += i))
-> std::remove_reference_t<decltype(
D(std::declval<D &>()),
std::declval<D &>() += i,
std::declval<D &>())>
{
D retval = derived();
retval += i;
return retval;
}
friend BOOST_STL_INTERFACES_HIDDEN_FRIEND_CONSTEXPR Derived
operator+(difference_type i, Derived it) noexcept
{
return it + i;
}
template<
typename D = Derived,
typename Enable =
std::enable_if_t<!v1_dtl::plus_eq<D, difference_type>::value>>
constexpr auto
operator--() noexcept(noexcept(--access::base(std::declval<D &>())))
-> decltype(--access::base(std::declval<D &>()), std::declval<D &>())
{
--access::base(derived());
return derived();
}
template<typename D = Derived>
constexpr auto operator--() noexcept(noexcept(
D(std::declval<D &>()), std::declval<D &>() += -difference_type(1)))
-> decltype(
std::declval<D &>() += -difference_type(1), std::declval<D &>())
{
derived() += -difference_type(1);
return derived();
}
template<typename D = Derived>
constexpr auto operator--(int)noexcept(
noexcept(D(std::declval<D &>()), --std::declval<D &>()))
-> std::remove_reference_t<decltype(
D(std::declval<D &>()),
--std::declval<D &>(),
std::declval<D &>())>
{
D retval = derived();
--derived();
return retval;
}
template<typename D = Derived>
constexpr D & operator-=(difference_type i) noexcept
{
derived() += -i;
return derived();
}
template<typename D = Derived>
constexpr auto operator-(D other) const noexcept(noexcept(
access::base(std::declval<D const &>()) - access::base(other)))
-> decltype(
access::base(std::declval<D const &>()) - access::base(other))
{
return access::base(derived()) - access::base(other);
}
friend BOOST_STL_INTERFACES_HIDDEN_FRIEND_CONSTEXPR Derived
operator-(Derived it, difference_type i) noexcept
{
Derived retval = it;
retval += -i;
return retval;
}
};
/** Implementation of `operator==()`, implemented in terms of the iterator
underlying IteratorInterface, for all iterators derived from
`iterator_interface`, except those with an iterator category derived
from `std::random_access_iterator_tag`. */
template<
typename IteratorInterface1,
typename IteratorInterface2,
typename Enable =
std::enable_if_t<!v1_dtl::ra_iter<IteratorInterface1>::value>>
constexpr auto
operator==(IteratorInterface1 lhs, IteratorInterface2 rhs) noexcept
-> decltype(
access::base(std::declval<IteratorInterface1 &>()) ==
access::base(std::declval<IteratorInterface2 &>()))
{
return access::base(lhs) == access::base(rhs);
}
/** Implementation of `operator==()` for all iterators derived from
`iterator_interface` that have an iterator category derived from
`std::random_access_iterator_tag`. */
template<
typename IteratorInterface1,
typename IteratorInterface2,
typename Enable =
std::enable_if_t<v1_dtl::ra_iter<IteratorInterface1>::value>>
constexpr auto
operator==(IteratorInterface1 lhs, IteratorInterface2 rhs) noexcept(
noexcept(detail::common_diff(lhs, rhs)))
-> decltype(
v1_dtl::derived_iterator(lhs), detail::common_diff(lhs, rhs) == 0)
{
return detail::common_diff(lhs, rhs) == 0;
}
/** Implementation of `operator!=()` for all iterators derived from
`iterator_interface`. */
template<typename IteratorInterface1, typename IteratorInterface2>
constexpr auto operator!=(
IteratorInterface1 lhs,
IteratorInterface2 rhs) noexcept(noexcept(!(lhs == rhs)))
-> decltype(v1_dtl::derived_iterator(lhs), !(lhs == rhs))
{
return !(lhs == rhs);
}
/** Implementation of `operator<()` for all iterators derived from
`iterator_interface` that have an iterator category derived from
`std::random_access_iterator_tag`. */
template<typename IteratorInterface1, typename IteratorInterface2>
constexpr auto
operator<(IteratorInterface1 lhs, IteratorInterface2 rhs) noexcept(
noexcept(detail::common_diff(lhs, rhs)))
-> decltype(
v1_dtl::derived_iterator(lhs), detail::common_diff(lhs, rhs) < 0)
{
return detail::common_diff(lhs, rhs) < 0;
}
/** Implementation of `operator<=()` for all iterators derived from
`iterator_interface` that have an iterator category derived from
`std::random_access_iterator_tag`. */
template<typename IteratorInterface1, typename IteratorInterface2>
constexpr auto
operator<=(IteratorInterface1 lhs, IteratorInterface2 rhs) noexcept(
noexcept(detail::common_diff(lhs, rhs)))
-> decltype(
v1_dtl::derived_iterator(lhs), detail::common_diff(lhs, rhs) <= 0)
{
return detail::common_diff(lhs, rhs) <= 0;
}
/** Implementation of `operator>()` for all iterators derived from
`iterator_interface` that have an iterator category derived from
`std::random_access_iterator_tag`. */
template<typename IteratorInterface1, typename IteratorInterface2>
constexpr auto
operator>(IteratorInterface1 lhs, IteratorInterface2 rhs) noexcept(
noexcept(detail::common_diff(lhs, rhs)))
-> decltype(
v1_dtl::derived_iterator(lhs), detail::common_diff(lhs, rhs) > 0)
{
return detail::common_diff(lhs, rhs) > 0;
}
/** Implementation of `operator>=()` for all iterators derived from
`iterator_interface` that have an iterator category derived from
`std::random_access_iterator_tag`. */
template<typename IteratorInterface1, typename IteratorInterface2>
constexpr auto
operator>=(IteratorInterface1 lhs, IteratorInterface2 rhs) noexcept(
noexcept(detail::common_diff(lhs, rhs)))
-> decltype(
v1_dtl::derived_iterator(lhs), detail::common_diff(lhs, rhs) >= 0)
{
return detail::common_diff(lhs, rhs) >= 0;
}
/** A template alias useful for defining proxy iterators. \see
`iterator_interface`. */
template<
typename Derived,
typename IteratorConcept,
typename ValueType,
typename Reference = ValueType,
typename DifferenceType = std::ptrdiff_t>
using proxy_iterator_interface = iterator_interface<
Derived,
IteratorConcept,
ValueType,
Reference,
proxy_arrow_result<Reference>,
DifferenceType>;
}}}
#if defined(BOOST_STL_INTERFACES_DOXYGEN) || BOOST_STL_INTERFACES_USE_CONCEPTS
namespace boost { namespace stl_interfaces { BOOST_STL_INTERFACES_NAMESPACE_V2 {
namespace v2_dtl {
template<typename Iterator>
struct iter_concept;
template<typename Iterator>
requires requires
{
typename std::iterator_traits<Iterator>::iterator_concept;
}
struct iter_concept<Iterator>
{
using type =
typename std::iterator_traits<Iterator>::iterator_concept;
};
template<typename Iterator>
requires(
!requires {
typename std::iterator_traits<Iterator>::iterator_concept;
} &&
requires {
typename std::iterator_traits<Iterator>::iterator_category;
})
struct iter_concept<Iterator>
{
using type =
typename std::iterator_traits<Iterator>::iterator_category;
};
template<typename Iterator>
requires(
!requires {
typename std::iterator_traits<Iterator>::iterator_concept;
} &&
!requires {
typename std::iterator_traits<Iterator>::iterator_category;
})
struct iter_concept<Iterator>
{
using type = std::random_access_iterator_tag;
};
template<typename Iterator>
struct iter_concept
{};
template<typename Iterator>
using iter_concept_t = typename iter_concept<Iterator>::type;
template<typename D, typename DifferenceType>
// clang-format off
concept plus_eq = requires (D d) { d += DifferenceType(1); };
// clang-format on
template<typename D, typename D2 = D>
// clang-format off
concept base_3way =
#if defined(__cpp_impl_three_way_comparison)
requires (D d, D2 d2) { access::base(d) <=> access::base(d2); };
#else
false;
#endif
// clang-format on
template<typename D1, typename D2 = D1>
// clang-format off
concept base_eq =
requires (D1 d1, D2 d2) { access::base(d1) == access::base(d2); };
// clang-format on
template<typename D, typename D2 = D>
// clang-format off
concept iter_sub = requires (D d, D2 d2) {
typename D::difference_type;
{d - d2} -> std::convertible_to<typename D::difference_type>;
};
// clang-format on
// This iterator concept -> category mapping scheme follows the one
// from zip_transform_view; see
// https://eel.is/c++draft/range.zip.transform.iterator#1.
template<typename IteratorConcept, typename ReferenceType>
constexpr auto category_tag()
{
if constexpr (std::is_base_of_v<
std::forward_iterator_tag,
IteratorConcept>) {
if constexpr (!std::is_reference_v<ReferenceType>) {
return std::input_iterator_tag{};
} else if constexpr (std::is_base_of_v<
std::random_access_iterator_tag,
IteratorConcept>) {
return std::random_access_iterator_tag{};
} else if constexpr (std::is_base_of_v<
std::bidirectional_iterator_tag,
IteratorConcept>) {
return std::bidirectional_iterator_tag{};
} else {
return std::forward_iterator_tag{};
}
} else {
return 0; // int means "no tag"
}
}
template<
typename IteratorConcept,
typename ReferenceType,
typename IteratorCategory =
decltype(v2_dtl::
category_tag<IteratorConcept, ReferenceType>())>
struct iterator_category_base
{
using iterator_category = IteratorCategory;
};
template<typename IteratorConcept, typename ReferenceType>
struct iterator_category_base<IteratorConcept, ReferenceType, int>
{};
template<typename IteratorConcept, typename ReferenceType>
constexpr bool non_input_tag()
{
if (std::same_as<IteratorConcept, std::input_iterator_tag>)
return false;
using tag_t =
decltype(v2_dtl::
category_tag<IteratorConcept, ReferenceType>());
return !std::same_as<tag_t, std::input_iterator_tag>;
}
}
// clang-format off
/** A CRTP template that one may derive from to make defining iterators
easier.
The template parameter `D` for `iterator_interface` may be an
incomplete type. Before any member of the resulting specialization of
`iterator_interface` other than special member functions is
referenced, `D` shall be complete, and model
`std::derived_from<iterator_interface<D>>`. */
template<
typename D,
typename IteratorConcept,
typename ValueType,
typename Reference = ValueType &,
typename Pointer = ValueType *,
typename DifferenceType = std::ptrdiff_t>
requires std::is_class_v<D> && std::same_as<D, std::remove_cv_t<D>>
struct iterator_interface
: v2_dtl::iterator_category_base<IteratorConcept, Reference>
{
private:
constexpr D& derived() noexcept {
return static_cast<D&>(*this);
}
constexpr const D& derived() const noexcept {
return static_cast<const D&>(*this);
}
public:
using iterator_concept = IteratorConcept;
using value_type = std::remove_const_t<ValueType>;
using reference = Reference;
using pointer = detail::pointer_t<Pointer, iterator_concept>;
using difference_type = DifferenceType;
constexpr decltype(auto) operator*()
requires requires (D d) { *access::base(d); } {
return *access::base(derived());
}
constexpr decltype(auto) operator*() const
requires requires (D const d) { *access::base(d); } {
return *access::base(derived());
}
constexpr auto operator->()
requires (!std::same_as<pointer, void> && std::is_reference_v<reference> &&
requires (D d) { *d; }) {
return detail::make_pointer<pointer, reference>(*derived());
}
constexpr auto operator->() const
requires (!std::same_as<pointer, void> && std::is_reference_v<reference> &&
requires (D const d) { *d; }) {
return detail::make_pointer<pointer, reference>(*derived());
}
constexpr decltype(auto) operator[](difference_type n) const
requires requires (D const d) { d + n; } {
D retval = derived();
retval += n;
return *retval;
}
constexpr decltype(auto) operator++()
requires requires (D d) { ++access::base(d); } &&
(!v2_dtl::plus_eq<D, difference_type>) {
++access::base(derived());
return derived();
}
constexpr decltype(auto) operator++()
requires requires (D d) { d += difference_type(1); } {
return derived() += difference_type(1);
}
constexpr auto operator++(int) requires requires (D d) { ++d; } {
if constexpr (std::is_same_v<IteratorConcept, std::input_iterator_tag>){
++derived();
} else {
D retval = derived();
++derived();
return retval;
}
}
constexpr decltype(auto) operator+=(difference_type n)
requires requires (D d) { access::base(d) += n; } {
access::base(derived()) += n;
return derived();
}
constexpr decltype(auto) operator--()
requires requires (D d) { --access::base(d); } &&
(!v2_dtl::plus_eq<D, difference_type>) {
--access::base(derived());
return derived();
}
constexpr decltype(auto) operator--()
requires requires (D d) { d += -difference_type(1); } {
return derived() += -difference_type(1);
}
constexpr auto operator--(int) requires requires (D d) { --d; } {
D retval = derived();
--derived();
return retval;
}
constexpr decltype(auto) operator-=(difference_type n)
requires requires (D d) { d += -n; } {
return derived() += -n;
}
};
namespace v2_dtl {
template<
typename D,
typename IteratorConcept,
typename ValueType,
typename Reference,
typename Pointer,
typename DifferenceType>
void derived_iterator(v2::iterator_interface<
D,
IteratorConcept,
ValueType,
Reference,
Pointer,
DifferenceType> const &);
template<typename D>
concept derived_iter = requires (D d) { v2_dtl::derived_iterator(d); };
}
template<typename D>
constexpr auto operator+(D it, typename D::difference_type n)
requires v2_dtl::derived_iter<D> && requires { it += n; }
{ return it += n; }
template<typename D>
constexpr auto operator+(typename D::difference_type n, D it)
requires v2_dtl::derived_iter<D> && requires { it += n; }
{ return it += n; }
template<typename D1, typename D2>
constexpr auto operator-(D1 lhs, D2 rhs)
requires v2_dtl::derived_iter<D1> && v2_dtl::derived_iter<D2> &&
requires { access::base(lhs) - access::base(rhs); }
{ return access::base(lhs) - access::base(rhs); }
template<typename D>
constexpr auto operator-(D it, typename D::difference_type n)
requires v2_dtl::derived_iter<D> && requires { it += -n; }
{ return it += -n; }
#if defined(__cpp_lib_three_way_comparison)
template<typename D1, typename D2>
constexpr auto operator<=>(D1 lhs, D2 rhs)
requires v2_dtl::derived_iter<D1> && v2_dtl::derived_iter<D2> &&
(v2_dtl::base_3way<D1, D2> || v2_dtl::iter_sub<D1, D2>) {
if constexpr (v2_dtl::base_3way<D1, D2>) {
return access::base(lhs) <=> access::base(rhs);
} else {
using diff_type = typename D1::difference_type;
diff_type const diff = rhs - lhs;
return diff < diff_type(0) ? std::strong_ordering::less :
diff_type(0) < diff ? std::strong_ordering::greater :
std::strong_ordering::equal;
}
}
#endif
template<typename D1, typename D2>
constexpr bool operator<(D1 lhs, D2 rhs)
requires v2_dtl::derived_iter<D1> && v2_dtl::derived_iter<D2> && v2_dtl::iter_sub<D1, D2>
{ return (lhs - rhs) < typename D1::difference_type(0); }
template<typename D1, typename D2>
constexpr bool operator<=(D1 lhs, D2 rhs)
requires v2_dtl::derived_iter<D1> && v2_dtl::derived_iter<D2> && v2_dtl::iter_sub<D1, D2>
{ return (lhs - rhs) <= typename D1::difference_type(0); }
template<typename D1, typename D2>
constexpr bool operator>(D1 lhs, D2 rhs)
requires v2_dtl::derived_iter<D1> && v2_dtl::derived_iter<D2> && v2_dtl::iter_sub<D1, D2>
{ return (lhs - rhs) > typename D1::difference_type(0); }
template<typename D1, typename D2>
constexpr bool operator>=(D1 lhs, D2 rhs)
requires v2_dtl::derived_iter<D1> && v2_dtl::derived_iter<D2> && v2_dtl::iter_sub<D1, D2>
{ return (lhs - rhs) >= typename D1::difference_type(0); }
template<typename D1, typename D2>
constexpr bool operator==(D1 lhs, D2 rhs)
requires v2_dtl::derived_iter<D1> && v2_dtl::derived_iter<D2> &&
detail::interoperable<D1, D2>::value &&
(v2_dtl::base_eq<D1, D2> || v2_dtl::iter_sub<D1, D2>) {
if constexpr (v2_dtl::base_eq<D1, D2>) {
return (access::base(lhs) == access::base(rhs));
} else if constexpr (v2_dtl::iter_sub<D1, D2>) {
return (lhs - rhs) == typename D1::difference_type(0);
}
}
template<typename D1, typename D2>
constexpr auto operator!=(D1 lhs, D2 rhs) -> decltype(!(lhs == rhs))
requires v2_dtl::derived_iter<D1> && v2_dtl::derived_iter<D2>
{ return !(lhs == rhs); }
// clang-format on
/** A template alias useful for defining proxy iterators. \see
`iterator_interface`. */
template<
typename Derived,
typename IteratorConcept,
typename ValueType,
typename Reference = ValueType,
typename DifferenceType = std::ptrdiff_t>
using proxy_iterator_interface = iterator_interface<
Derived,
IteratorConcept,
ValueType,
Reference,
proxy_arrow_result<Reference>,
DifferenceType>;
}}}
#endif
#if defined(BOOST_STL_INTERFACES_DOXYGEN) || BOOST_STL_INTERFACES_USE_DEDUCED_THIS
namespace boost { namespace stl_interfaces { BOOST_STL_INTERFACES_NAMESPACE_V3 {
// clang-format off
/** A base template that one may derive from to make defining iterators
easier. */
template<
typename IteratorConcept,
typename ValueType,
typename Reference = ValueType &,
typename Pointer = ValueType *,
typename DifferenceType = std::ptrdiff_t>
struct iterator_interface
: v2::v2_dtl::iterator_category_base<IteratorConcept, Reference>
{
using iterator_concept = IteratorConcept;
using value_type = std::remove_const_t<ValueType>;
using reference = Reference;
using pointer = detail::pointer_t<Pointer, iterator_concept>;
using difference_type = DifferenceType;
constexpr decltype(auto) operator*(this auto&& self)
requires requires { *access::base(self); } {
return *access::base(self);
}
constexpr auto operator->(this auto&& self)
requires (!std::same_as<pointer, void>) && std::is_reference_v<reference> && requires { *self; } {
return detail::make_pointer<pointer, reference>(*self);
}
constexpr decltype(auto) operator[](this auto const& self, difference_type n)
requires requires { self + n; } {
auto retval = self;
retval = retval + n;
return *retval;
}
constexpr decltype(auto) operator++(this auto& self)
requires requires { ++access::base(self); } && (!requires { self += difference_type(1); }) {
++access::base(self);
return self;
}
constexpr decltype(auto) operator++(this auto& self)
requires requires { self += difference_type(1); } {
return self += difference_type(1);
}
constexpr auto operator++(this auto& self, int) requires requires { ++self; } {
if constexpr (std::is_same_v<IteratorConcept, std::input_iterator_tag>){
++self;
} else {
auto retval = self;
++self;
return retval;
}
}
constexpr decltype(auto) operator+=(this auto& self, difference_type n)
requires requires { access::base(self) += n; } {
access::base(self) += n;
return self;
}
constexpr decltype(auto) operator--(this auto& self)
requires requires { --access::base(self); } && (!requires { self += difference_type(1); }) {
--access::base(self);
return self;
}
constexpr decltype(auto) operator--(this auto& self)
requires requires { self += -difference_type(1); } {
return self += -difference_type(1);
}
constexpr auto operator--(this auto& self, int) requires requires { --self; } {
auto retval = self;
--self;
return retval;
}
constexpr decltype(auto) operator-=(this auto& self, difference_type n)
requires requires { self += -n; } {
return self += -n;
}
};
namespace v3_dtl {
template<
typename IteratorConcept,
typename ValueType,
typename Reference,
typename Pointer,
typename DifferenceType>
void derived_iterator(v3::iterator_interface<
IteratorConcept,
ValueType,
Reference,
Pointer,
DifferenceType> const &);
template<typename D>
concept derived_iter = requires (D d) { v3_dtl::derived_iterator(d); };
}
template<typename D>
constexpr auto operator+(D it, typename D::difference_type n)
requires v3_dtl::derived_iter<D> && requires { it += n; }
{ return it += n; }
template<typename D>
constexpr auto operator+(typename D::difference_type n, D it)
requires v3_dtl::derived_iter<D> && requires { it += n; }
{ return it += n; }
template<typename D1, typename D2>
constexpr auto operator-(D1 lhs, D2 rhs)
requires v3_dtl::derived_iter<D1> && v3_dtl::derived_iter<D2> &&
requires { access::base(lhs) - access::base(rhs); }
{ return access::base(lhs) - access::base(rhs); }
template<typename D>
constexpr auto operator-(D it, typename D::difference_type n)
requires v3_dtl::derived_iter<D> && requires { it += -n; }
{ return it += -n; }
#if defined(__cpp_lib_three_way_comparison)
template<typename D1, typename D2>
constexpr auto operator<=>(D1 lhs, D2 rhs)
requires v3_dtl::derived_iter<D1> && v3_dtl::derived_iter<D2> &&
(v2::v2_dtl::base_3way<D1, D2> || v2::v2_dtl::iter_sub<D1, D2>) {
if constexpr (v2::v2_dtl::base_3way<D1, D2>) {
return access::base(lhs) <=> access::base(rhs);
} else {
using diff_type = typename D1::difference_type;
diff_type const diff = rhs - lhs;
return diff < diff_type(0) ? std::strong_ordering::less :
diff_type(0) < diff ? std::strong_ordering::greater :
std::strong_ordering::equal;
}
}
#endif
template<typename D1, typename D2>
constexpr bool operator<(D1 lhs, D2 rhs)
requires v3_dtl::derived_iter<D1> && v3_dtl::derived_iter<D2> && v2::v2_dtl::iter_sub<D1, D2>
{ return (lhs - rhs) < typename D1::difference_type(0); }
template<typename D1, typename D2>
constexpr bool operator<=(D1 lhs, D2 rhs)
requires v3_dtl::derived_iter<D1> && v3_dtl::derived_iter<D2> && v2::v2_dtl::iter_sub<D1, D2>
{ return (lhs - rhs) <= typename D1::difference_type(0); }
template<typename D1, typename D2>
constexpr bool operator>(D1 lhs, D2 rhs)
requires v3_dtl::derived_iter<D1> && v3_dtl::derived_iter<D2> && v2::v2_dtl::iter_sub<D1, D2>
{ return (lhs - rhs) > typename D1::difference_type(0); }
template<typename D1, typename D2>
constexpr bool operator>=(D1 lhs, D2 rhs)
requires v3_dtl::derived_iter<D1> && v3_dtl::derived_iter<D2> && v2::v2_dtl::iter_sub<D1, D2>
{ return (lhs - rhs) >= typename D1::difference_type(0); }
template<typename D1, typename D2>
constexpr bool operator==(D1 lhs, D2 rhs)
requires v3_dtl::derived_iter<D1> && v3_dtl::derived_iter<D2> &&
detail::interoperable<D1, D2>::value &&
(v2::v2_dtl::base_eq<D1, D2> || v2::v2_dtl::iter_sub<D1, D2>) {
if constexpr (v2::v2_dtl::base_eq<D1, D2>) {
return (access::base(lhs) == access::base(rhs));
} else if constexpr (v2::v2_dtl::iter_sub<D1, D2>) {
return (lhs - rhs) == typename D1::difference_type(0);
}
}
template<typename D1, typename D2>
constexpr auto operator!=(D1 lhs, D2 rhs) -> decltype(!(lhs == rhs))
requires v3_dtl::derived_iter<D1> && v3_dtl::derived_iter<D2>
{ return !(lhs == rhs); }
// clang-format on
/** A template alias useful for defining proxy iterators. \see
`iterator_interface`. */
template<
typename IteratorConcept,
typename ValueType,
typename Reference = ValueType,
typename DifferenceType = std::ptrdiff_t>
using proxy_iterator_interface = iterator_interface<
IteratorConcept,
ValueType,
Reference,
proxy_arrow_result<Reference>,
DifferenceType>;
}}}
#endif
#ifdef BOOST_STL_INTERFACES_DOXYGEN
/** `static_asserts` that type `type` models concept `concept_name`. This is
useful for checking that an iterator, view, etc. that you write using one
of the *`_interface` templates models the right C++ concept.
For example: `BOOST_STL_INTERFACES_STATIC_ASSERT_CONCEPT(my_iter,
std::input_iterator)`.
\note This macro expands to nothing when `__cpp_lib_concepts` is not
defined. */
#define BOOST_STL_INTERFACES_STATIC_ASSERT_CONCEPT(type, concept_name)
/** `static_asserts` that the types of all typedefs in
`std::iterator_traits<iter>` match the remaining macro parameters. This
is useful for checking that an iterator you write using
`iterator_interface` has the correct iterator traits.
For example: `BOOST_STL_INTERFACES_STATIC_ASSERT_ITERATOR_TRAITS(my_iter,
std::input_iterator_tag, std::input_iterator, int, int &, int *, std::ptrdiff_t)`.
\note This macro ignores the `concept` parameter when `__cpp_lib_concepts`
is not defined. */
#define BOOST_STL_INTERFACES_STATIC_ASSERT_ITERATOR_TRAITS( \
iter, category, concept, value_type, reference, pointer, difference_type)
#else
#define BOOST_STL_INTERFACES_STATIC_ASSERT_ITERATOR_CONCEPT_IMPL( \
type, concept_name) \
static_assert(concept_name<type>, "");
#if BOOST_STL_INTERFACES_USE_CONCEPTS
#define BOOST_STL_INTERFACES_STATIC_ASSERT_CONCEPT(iter, concept_name) \
BOOST_STL_INTERFACES_STATIC_ASSERT_ITERATOR_CONCEPT_IMPL(iter, concept_name)
#else
#define BOOST_STL_INTERFACES_STATIC_ASSERT_CONCEPT(iter, concept_name)
#endif
#define BOOST_STL_INTERFACES_STATIC_ASSERT_ITERATOR_TRAITS_IMPL( \
iter, category, value_t, ref, ptr, diff_t) \
static_assert( \
std::is_same< \
typename std::iterator_traits<iter>::value_type, \
value_t>::value, \
""); \
static_assert( \
std::is_same<typename std::iterator_traits<iter>::reference, ref>:: \
value, \
""); \
static_assert( \
std::is_same<typename std::iterator_traits<iter>::pointer, ptr>:: \
value, \
""); \
static_assert( \
std::is_same< \
typename std::iterator_traits<iter>::difference_type, \
diff_t>::value, \
"");
#define BOOST_STL_INTERFACES_STATIC_ASSERT_ITERATOR_TRAITS( \
iter, category, concept, value_type, reference, pointer, difference_type) \
BOOST_STL_INTERFACES_STATIC_ASSERT_ITERATOR_TRAITS_IMPL( \
iter, category, value_type, reference, pointer, difference_type)
#endif
#endif