diff options
Diffstat (limited to 'contrib/src/boost/iterator/iterator_facade.hpp')
-rw-r--r-- | contrib/src/boost/iterator/iterator_facade.hpp | 1960 |
1 files changed, 980 insertions, 980 deletions
diff --git a/contrib/src/boost/iterator/iterator_facade.hpp b/contrib/src/boost/iterator/iterator_facade.hpp index 7b11d0a..1bb8bd9 100644 --- a/contrib/src/boost/iterator/iterator_facade.hpp +++ b/contrib/src/boost/iterator/iterator_facade.hpp @@ -1,980 +1,980 @@ -// (C) Copyright David Abrahams 2002. -// (C) Copyright Jeremy Siek 2002. -// (C) Copyright Thomas Witt 2002. -// 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_ITERATOR_FACADE_23022003THW_HPP -#define BOOST_ITERATOR_FACADE_23022003THW_HPP - -#include <boost/config.hpp> -#include <boost/iterator.hpp> -#include <boost/iterator/interoperable.hpp> -#include <boost/iterator/iterator_traits.hpp> -#include <boost/iterator/iterator_categories.hpp> - -#include <boost/iterator/detail/facade_iterator_category.hpp> -#include <boost/iterator/detail/enable_if.hpp> - -#include <boost/static_assert.hpp> -#include <boost/utility/addressof.hpp> - -#include <boost/type_traits/is_same.hpp> -#include <boost/type_traits/add_const.hpp> -#include <boost/type_traits/add_pointer.hpp> -#include <boost/type_traits/add_lvalue_reference.hpp> -#include <boost/type_traits/remove_const.hpp> -#include <boost/type_traits/remove_reference.hpp> -#include <boost/type_traits/is_convertible.hpp> -#include <boost/type_traits/is_pod.hpp> - -#include <boost/mpl/eval_if.hpp> -#include <boost/mpl/if.hpp> -#include <boost/mpl/or.hpp> -#include <boost/mpl/and.hpp> -#include <boost/mpl/not.hpp> -#include <boost/mpl/always.hpp> -#include <boost/mpl/apply.hpp> -#include <boost/mpl/identity.hpp> - -#include <boost/iterator/detail/config_def.hpp> // this goes last - -namespace boost { -namespace iterators { - - // This forward declaration is required for the friend declaration - // in iterator_core_access - template <class I, class V, class TC, class R, class D> class iterator_facade; - - namespace detail - { - // A binary metafunction class that always returns bool. VC6 - // ICEs on mpl::always<bool>, probably because of the default - // parameters. - struct always_bool2 - { - template <class T, class U> - struct apply - { - typedef bool type; - }; - }; - - // The type trait checks if the category or traversal is at least as advanced as the specified required traversal - template< typename CategoryOrTraversal, typename Required > - struct is_traversal_at_least : - public boost::is_convertible< typename iterator_category_to_traversal< CategoryOrTraversal >::type, Required > - {}; - - // - // enable if for use in operator implementation. - // - template < - class Facade1 - , class Facade2 - , class Return - > - struct enable_if_interoperable : - public boost::iterators::enable_if< - is_interoperable< Facade1, Facade2 > - , Return - > - {}; - - // - // enable if for use in implementation of operators specific for random access traversal. - // - template < - class Facade1 - , class Facade2 - , class Return - > - struct enable_if_interoperable_and_random_access_traversal : - public boost::iterators::enable_if< - mpl::and_< - is_interoperable< Facade1, Facade2 > - , is_traversal_at_least< typename iterator_category< Facade1 >::type, random_access_traversal_tag > - , is_traversal_at_least< typename iterator_category< Facade2 >::type, random_access_traversal_tag > - > - , Return - > - {}; - - // - // Generates associated types for an iterator_facade with the - // given parameters. - // - template < - class ValueParam - , class CategoryOrTraversal - , class Reference - , class Difference - > - struct iterator_facade_types - { - typedef typename facade_iterator_category< - CategoryOrTraversal, ValueParam, Reference - >::type iterator_category; - - typedef typename remove_const<ValueParam>::type value_type; - - // Not the real associated pointer type - typedef typename mpl::eval_if< - boost::iterators::detail::iterator_writability_disabled<ValueParam,Reference> - , add_pointer<const value_type> - , add_pointer<value_type> - >::type pointer; - -# if defined(BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION) \ - && (BOOST_WORKAROUND(_STLPORT_VERSION, BOOST_TESTED_AT(0x452)) \ - || BOOST_WORKAROUND(BOOST_DINKUMWARE_STDLIB, BOOST_TESTED_AT(310))) \ - || BOOST_WORKAROUND(BOOST_RWSTD_VER, BOOST_TESTED_AT(0x20101)) \ - || BOOST_WORKAROUND(BOOST_DINKUMWARE_STDLIB, <= 310) - - // To interoperate with some broken library/compiler - // combinations, user-defined iterators must be derived from - // std::iterator. It is possible to implement a standard - // library for broken compilers without this limitation. -# define BOOST_ITERATOR_FACADE_NEEDS_ITERATOR_BASE 1 - - typedef - iterator<iterator_category, value_type, Difference, pointer, Reference> - base; -# endif - }; - - // iterators whose dereference operators reference the same value - // for all iterators into the same sequence (like many input - // iterators) need help with their postfix ++: the referenced - // value must be read and stored away before the increment occurs - // so that *a++ yields the originally referenced element and not - // the next one. - template <class Iterator> - class postfix_increment_proxy - { - typedef typename iterator_value<Iterator>::type value_type; - public: - explicit postfix_increment_proxy(Iterator const& x) - : stored_value(*x) - {} - - // Returning a mutable reference allows nonsense like - // (*r++).mutate(), but it imposes fewer assumptions about the - // behavior of the value_type. In particular, recall that - // (*r).mutate() is legal if operator* returns by value. - value_type& - operator*() const - { - return this->stored_value; - } - private: - mutable value_type stored_value; - }; - - // - // In general, we can't determine that such an iterator isn't - // writable -- we also need to store a copy of the old iterator so - // that it can be written into. - template <class Iterator> - class writable_postfix_increment_proxy - { - typedef typename iterator_value<Iterator>::type value_type; - public: - explicit writable_postfix_increment_proxy(Iterator const& x) - : stored_value(*x) - , stored_iterator(x) - {} - - // Dereferencing must return a proxy so that both *r++ = o and - // value_type(*r++) can work. In this case, *r is the same as - // *r++, and the conversion operator below is used to ensure - // readability. - writable_postfix_increment_proxy const& - operator*() const - { - return *this; - } - - // Provides readability of *r++ - operator value_type&() const - { - return stored_value; - } - - // Provides writability of *r++ - template <class T> - T const& operator=(T const& x) const - { - *this->stored_iterator = x; - return x; - } - - // This overload just in case only non-const objects are writable - template <class T> - T& operator=(T& x) const - { - *this->stored_iterator = x; - return x; - } - - // Provides X(r++) - operator Iterator const&() const - { - return stored_iterator; - } - - private: - mutable value_type stored_value; - Iterator stored_iterator; - }; - -# ifdef BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION - - template <class Reference, class Value> - struct is_non_proxy_reference_impl - { - static Reference r; - - template <class R> - static typename mpl::if_< - is_convertible< - R const volatile* - , Value const volatile* - > - , char[1] - , char[2] - >::type& helper(R const&); - - BOOST_STATIC_CONSTANT(bool, value = sizeof(helper(r)) == 1); - }; - - template <class Reference, class Value> - struct is_non_proxy_reference - : mpl::bool_< - is_non_proxy_reference_impl<Reference, Value>::value - > - {}; -# else - template <class Reference, class Value> - struct is_non_proxy_reference - : is_convertible< - typename remove_reference<Reference>::type - const volatile* - , Value const volatile* - > - {}; -# endif - - // A metafunction to choose the result type of postfix ++ - // - // Because the C++98 input iterator requirements say that *r++ has - // type T (value_type), implementations of some standard - // algorithms like lexicographical_compare may use constructions - // like: - // - // *r++ < *s++ - // - // If *r++ returns a proxy (as required if r is writable but not - // multipass), this sort of expression will fail unless the proxy - // supports the operator<. Since there are any number of such - // operations, we're not going to try to support them. Therefore, - // even if r++ returns a proxy, *r++ will only return a proxy if - // *r also returns a proxy. - template <class Iterator, class Value, class Reference, class CategoryOrTraversal> - struct postfix_increment_result - : mpl::eval_if< - mpl::and_< - // A proxy is only needed for readable iterators - is_convertible< - Reference - // Use add_lvalue_reference to form `reference to Value` due to - // some (strict) C++03 compilers (e.g. `gcc -std=c++03`) reject - // 'reference-to-reference' in the template which described in CWG - // DR106. - // http://www.open-std.org/Jtc1/sc22/wg21/docs/cwg_defects.html#106 - , typename add_lvalue_reference<Value const>::type - > - - // No multipass iterator can have values that disappear - // before positions can be re-visited - , mpl::not_< - is_convertible< - typename iterator_category_to_traversal<CategoryOrTraversal>::type - , forward_traversal_tag - > - > - > - , mpl::if_< - is_non_proxy_reference<Reference,Value> - , postfix_increment_proxy<Iterator> - , writable_postfix_increment_proxy<Iterator> - > - , mpl::identity<Iterator> - > - {}; - - // operator->() needs special support for input iterators to strictly meet the - // standard's requirements. If *i is not a reference type, we must still - // produce an lvalue to which a pointer can be formed. We do that by - // returning a proxy object containing an instance of the reference object. - template <class Reference, class Pointer> - struct operator_arrow_dispatch // proxy references - { - struct proxy - { - explicit proxy(Reference const & x) : m_ref(x) {} - Reference* operator->() { return boost::addressof(m_ref); } - // This function is needed for MWCW and BCC, which won't call - // operator-> again automatically per 13.3.1.2 para 8 - operator Reference*() { return boost::addressof(m_ref); } - Reference m_ref; - }; - typedef proxy result_type; - static result_type apply(Reference const & x) - { - return result_type(x); - } - }; - - template <class T, class Pointer> - struct operator_arrow_dispatch<T&, Pointer> // "real" references - { - typedef Pointer result_type; - static result_type apply(T& x) - { - return boost::addressof(x); - } - }; - - // A proxy return type for operator[], needed to deal with - // iterators that may invalidate referents upon destruction. - // Consider the temporary iterator in *(a + n) - template <class Iterator> - class operator_brackets_proxy - { - // Iterator is actually an iterator_facade, so we do not have to - // go through iterator_traits to access the traits. - typedef typename Iterator::reference reference; - typedef typename Iterator::value_type value_type; - - public: - operator_brackets_proxy(Iterator const& iter) - : m_iter(iter) - {} - - operator reference() const - { - return *m_iter; - } - - operator_brackets_proxy& operator=(value_type const& val) - { - *m_iter = val; - return *this; - } - - private: - Iterator m_iter; - }; - - // A metafunction that determines whether operator[] must return a - // proxy, or whether it can simply return a copy of the value_type. - template <class ValueType, class Reference> - struct use_operator_brackets_proxy - : mpl::not_< - mpl::and_< - // Really we want an is_copy_constructible trait here, - // but is_POD will have to suffice in the meantime. - boost::is_POD<ValueType> - , iterator_writability_disabled<ValueType,Reference> - > - > - {}; - - template <class Iterator, class Value, class Reference> - struct operator_brackets_result - { - typedef typename mpl::if_< - use_operator_brackets_proxy<Value,Reference> - , operator_brackets_proxy<Iterator> - , Value - >::type type; - }; - - template <class Iterator> - operator_brackets_proxy<Iterator> make_operator_brackets_result(Iterator const& iter, mpl::true_) - { - return operator_brackets_proxy<Iterator>(iter); - } - - template <class Iterator> - typename Iterator::value_type make_operator_brackets_result(Iterator const& iter, mpl::false_) - { - return *iter; - } - - struct choose_difference_type - { - template <class I1, class I2> - struct apply - : -# ifdef BOOST_NO_ONE_WAY_ITERATOR_INTEROP - iterator_difference<I1> -# else - mpl::eval_if< - is_convertible<I2,I1> - , iterator_difference<I1> - , iterator_difference<I2> - > -# endif - {}; - - }; - - template < - class Derived - , class Value - , class CategoryOrTraversal - , class Reference - , class Difference - , bool IsBidirectionalTraversal - , bool IsRandomAccessTraversal - > - class iterator_facade_base; - - } // namespace detail - - - // Macros which describe the declarations of binary operators -# ifdef BOOST_NO_STRICT_ITERATOR_INTEROPERABILITY -# define BOOST_ITERATOR_FACADE_INTEROP_HEAD_IMPL(prefix, op, result_type, enabler) \ - template < \ - class Derived1, class V1, class TC1, class Reference1, class Difference1 \ - , class Derived2, class V2, class TC2, class Reference2, class Difference2 \ - > \ - prefix typename mpl::apply2<result_type,Derived1,Derived2>::type \ - operator op( \ - iterator_facade<Derived1, V1, TC1, Reference1, Difference1> const& lhs \ - , iterator_facade<Derived2, V2, TC2, Reference2, Difference2> const& rhs) -# else -# define BOOST_ITERATOR_FACADE_INTEROP_HEAD_IMPL(prefix, op, result_type, enabler) \ - template < \ - class Derived1, class V1, class TC1, class Reference1, class Difference1 \ - , class Derived2, class V2, class TC2, class Reference2, class Difference2 \ - > \ - prefix typename enabler< \ - Derived1, Derived2 \ - , typename mpl::apply2<result_type,Derived1,Derived2>::type \ - >::type \ - operator op( \ - iterator_facade<Derived1, V1, TC1, Reference1, Difference1> const& lhs \ - , iterator_facade<Derived2, V2, TC2, Reference2, Difference2> const& rhs) -# endif - -# define BOOST_ITERATOR_FACADE_INTEROP_HEAD(prefix, op, result_type) \ - BOOST_ITERATOR_FACADE_INTEROP_HEAD_IMPL(prefix, op, result_type, boost::iterators::detail::enable_if_interoperable) - -# define BOOST_ITERATOR_FACADE_INTEROP_RANDOM_ACCESS_HEAD(prefix, op, result_type) \ - BOOST_ITERATOR_FACADE_INTEROP_HEAD_IMPL(prefix, op, result_type, boost::iterators::detail::enable_if_interoperable_and_random_access_traversal) - -# define BOOST_ITERATOR_FACADE_PLUS_HEAD(prefix,args) \ - template <class Derived, class V, class TC, class R, class D> \ - prefix typename boost::iterators::enable_if< \ - boost::iterators::detail::is_traversal_at_least< TC, boost::iterators::random_access_traversal_tag >, \ - Derived \ - >::type operator+ args - - // - // Helper class for granting access to the iterator core interface. - // - // The simple core interface is used by iterator_facade. The core - // interface of a user/library defined iterator type should not be made public - // so that it does not clutter the public interface. Instead iterator_core_access - // should be made friend so that iterator_facade can access the core - // interface through iterator_core_access. - // - class iterator_core_access - { -# if defined(BOOST_NO_MEMBER_TEMPLATE_FRIENDS) - // Tasteless as this may seem, making all members public allows member templates - // to work in the absence of member template friends. - public: -# else - - template <class I, class V, class TC, class R, class D> friend class iterator_facade; - template <class I, class V, class TC, class R, class D, bool IsBidirectionalTraversal, bool IsRandomAccessTraversal> - friend class detail::iterator_facade_base; - -# define BOOST_ITERATOR_FACADE_RELATION(op) \ - BOOST_ITERATOR_FACADE_INTEROP_HEAD(friend,op, boost::iterators::detail::always_bool2); - - BOOST_ITERATOR_FACADE_RELATION(==) - BOOST_ITERATOR_FACADE_RELATION(!=) - -# undef BOOST_ITERATOR_FACADE_RELATION - -# define BOOST_ITERATOR_FACADE_RANDOM_ACCESS_RELATION(op) \ - BOOST_ITERATOR_FACADE_INTEROP_RANDOM_ACCESS_HEAD(friend,op, boost::iterators::detail::always_bool2); - - BOOST_ITERATOR_FACADE_RANDOM_ACCESS_RELATION(<) - BOOST_ITERATOR_FACADE_RANDOM_ACCESS_RELATION(>) - BOOST_ITERATOR_FACADE_RANDOM_ACCESS_RELATION(<=) - BOOST_ITERATOR_FACADE_RANDOM_ACCESS_RELATION(>=) - -# undef BOOST_ITERATOR_FACADE_RANDOM_ACCESS_RELATION - - BOOST_ITERATOR_FACADE_INTEROP_RANDOM_ACCESS_HEAD( - friend, -, boost::iterators::detail::choose_difference_type) - ; - - BOOST_ITERATOR_FACADE_PLUS_HEAD( - friend inline - , (iterator_facade<Derived, V, TC, R, D> const& - , typename Derived::difference_type) - ) - ; - - BOOST_ITERATOR_FACADE_PLUS_HEAD( - friend inline - , (typename Derived::difference_type - , iterator_facade<Derived, V, TC, R, D> const&) - ) - ; - -# endif - - template <class Facade> - static typename Facade::reference dereference(Facade const& f) - { - return f.dereference(); - } - - template <class Facade> - static void increment(Facade& f) - { - f.increment(); - } - - template <class Facade> - static void decrement(Facade& f) - { - f.decrement(); - } - - template <class Facade1, class Facade2> - static bool equal(Facade1 const& f1, Facade2 const& f2, mpl::true_) - { - return f1.equal(f2); - } - - template <class Facade1, class Facade2> - static bool equal(Facade1 const& f1, Facade2 const& f2, mpl::false_) - { - return f2.equal(f1); - } - - template <class Facade> - static void advance(Facade& f, typename Facade::difference_type n) - { - f.advance(n); - } - - template <class Facade1, class Facade2> - static typename Facade1::difference_type distance_from( - Facade1 const& f1, Facade2 const& f2, mpl::true_) - { - return -f1.distance_to(f2); - } - - template <class Facade1, class Facade2> - static typename Facade2::difference_type distance_from( - Facade1 const& f1, Facade2 const& f2, mpl::false_) - { - return f2.distance_to(f1); - } - - // - // Curiously Recurring Template interface. - // - template <class I, class V, class TC, class R, class D> - static I& derived(iterator_facade<I,V,TC,R,D>& facade) - { - return *static_cast<I*>(&facade); - } - - template <class I, class V, class TC, class R, class D> - static I const& derived(iterator_facade<I,V,TC,R,D> const& facade) - { - return *static_cast<I const*>(&facade); - } - - // objects of this class are useless - BOOST_DELETED_FUNCTION(iterator_core_access()) - }; - - namespace detail { - - // Implementation for forward traversal iterators - template < - class Derived - , class Value - , class CategoryOrTraversal - , class Reference - , class Difference - > - class iterator_facade_base< Derived, Value, CategoryOrTraversal, Reference, Difference, false, false > -# ifdef BOOST_ITERATOR_FACADE_NEEDS_ITERATOR_BASE - : public boost::iterators::detail::iterator_facade_types< - Value, CategoryOrTraversal, Reference, Difference - >::base -# undef BOOST_ITERATOR_FACADE_NEEDS_ITERATOR_BASE -# endif - { - private: - typedef boost::iterators::detail::iterator_facade_types< - Value, CategoryOrTraversal, Reference, Difference - > associated_types; - - typedef boost::iterators::detail::operator_arrow_dispatch< - Reference - , typename associated_types::pointer - > operator_arrow_dispatch_; - - public: - typedef typename associated_types::value_type value_type; - typedef Reference reference; - typedef Difference difference_type; - - typedef typename operator_arrow_dispatch_::result_type pointer; - - typedef typename associated_types::iterator_category iterator_category; - - public: - reference operator*() const - { - return iterator_core_access::dereference(this->derived()); - } - - pointer operator->() const - { - return operator_arrow_dispatch_::apply(*this->derived()); - } - - Derived& operator++() - { - iterator_core_access::increment(this->derived()); - return this->derived(); - } - - protected: - // - // Curiously Recurring Template interface. - // - Derived& derived() - { - return *static_cast<Derived*>(this); - } - - Derived const& derived() const - { - return *static_cast<Derived const*>(this); - } - }; - - // Implementation for bidirectional traversal iterators - template < - class Derived - , class Value - , class CategoryOrTraversal - , class Reference - , class Difference - > - class iterator_facade_base< Derived, Value, CategoryOrTraversal, Reference, Difference, true, false > : - public iterator_facade_base< Derived, Value, CategoryOrTraversal, Reference, Difference, false, false > - { - public: - Derived& operator--() - { - iterator_core_access::decrement(this->derived()); - return this->derived(); - } - - Derived operator--(int) - { - Derived tmp(this->derived()); - --*this; - return tmp; - } - }; - - // Implementation for random access traversal iterators - template < - class Derived - , class Value - , class CategoryOrTraversal - , class Reference - , class Difference - > - class iterator_facade_base< Derived, Value, CategoryOrTraversal, Reference, Difference, true, true > : - public iterator_facade_base< Derived, Value, CategoryOrTraversal, Reference, Difference, true, false > - { - private: - typedef iterator_facade_base< Derived, Value, CategoryOrTraversal, Reference, Difference, true, false > base_type; - - public: - typedef typename base_type::reference reference; - typedef typename base_type::difference_type difference_type; - - public: - typename boost::iterators::detail::operator_brackets_result<Derived, Value, reference>::type - operator[](difference_type n) const - { - typedef boost::iterators::detail::use_operator_brackets_proxy<Value, Reference> use_proxy; - - return boost::iterators::detail::make_operator_brackets_result<Derived>( - this->derived() + n - , use_proxy() - ); - } - - Derived& operator+=(difference_type n) - { - iterator_core_access::advance(this->derived(), n); - return this->derived(); - } - - Derived& operator-=(difference_type n) - { - iterator_core_access::advance(this->derived(), -n); - return this->derived(); - } - - Derived operator-(difference_type x) const - { - Derived result(this->derived()); - return result -= x; - } - }; - - } // namespace detail - - // - // iterator_facade - use as a public base class for defining new - // standard-conforming iterators. - // - template < - class Derived // The derived iterator type being constructed - , class Value - , class CategoryOrTraversal - , class Reference = Value& - , class Difference = std::ptrdiff_t - > - class iterator_facade : - public detail::iterator_facade_base< - Derived, - Value, - CategoryOrTraversal, - Reference, - Difference, - detail::is_traversal_at_least< CategoryOrTraversal, bidirectional_traversal_tag >::value, - detail::is_traversal_at_least< CategoryOrTraversal, random_access_traversal_tag >::value - > - { - protected: - // For use by derived classes - typedef iterator_facade<Derived,Value,CategoryOrTraversal,Reference,Difference> iterator_facade_; - }; - - template <class I, class V, class TC, class R, class D> - inline typename boost::iterators::detail::postfix_increment_result<I,V,R,TC>::type - operator++( - iterator_facade<I,V,TC,R,D>& i - , int - ) - { - typename boost::iterators::detail::postfix_increment_result<I,V,R,TC>::type - tmp(*static_cast<I*>(&i)); - - ++i; - - return tmp; - } - - - // - // Comparison operator implementation. The library supplied operators - // enables the user to provide fully interoperable constant/mutable - // iterator types. I.e. the library provides all operators - // for all mutable/constant iterator combinations. - // - // Note though that this kind of interoperability for constant/mutable - // iterators is not required by the standard for container iterators. - // All the standard asks for is a conversion mutable -> constant. - // Most standard library implementations nowadays provide fully interoperable - // iterator implementations, but there are still heavily used implementations - // that do not provide them. (Actually it's even worse, they do not provide - // them for only a few iterators.) - // - // ?? Maybe a BOOST_ITERATOR_NO_FULL_INTEROPERABILITY macro should - // enable the user to turn off mixed type operators - // - // The library takes care to provide only the right operator overloads. - // I.e. - // - // bool operator==(Iterator, Iterator); - // bool operator==(ConstIterator, Iterator); - // bool operator==(Iterator, ConstIterator); - // bool operator==(ConstIterator, ConstIterator); - // - // ... - // - // In order to do so it uses c++ idioms that are not yet widely supported - // by current compiler releases. The library is designed to degrade gracefully - // in the face of compiler deficiencies. In general compiler - // deficiencies result in less strict error checking and more obscure - // error messages, functionality is not affected. - // - // For full operation compiler support for "Substitution Failure Is Not An Error" - // (aka. enable_if) and boost::is_convertible is required. - // - // The following problems occur if support is lacking. - // - // Pseudo code - // - // --------------- - // AdaptorA<Iterator1> a1; - // AdaptorA<Iterator2> a2; - // - // // This will result in a no such overload error in full operation - // // If enable_if or is_convertible is not supported - // // The instantiation will fail with an error hopefully indicating that - // // there is no operator== for Iterator1, Iterator2 - // // The same will happen if no enable_if is used to remove - // // false overloads from the templated conversion constructor - // // of AdaptorA. - // - // a1 == a2; - // ---------------- - // - // AdaptorA<Iterator> a; - // AdaptorB<Iterator> b; - // - // // This will result in a no such overload error in full operation - // // If enable_if is not supported the static assert used - // // in the operator implementation will fail. - // // This will accidently work if is_convertible is not supported. - // - // a == b; - // ---------------- - // - -# ifdef BOOST_NO_ONE_WAY_ITERATOR_INTEROP -# define BOOST_ITERATOR_CONVERTIBLE(a,b) mpl::true_() -# else -# define BOOST_ITERATOR_CONVERTIBLE(a,b) is_convertible<a,b>() -# endif - -# define BOOST_ITERATOR_FACADE_INTEROP(op, result_type, return_prefix, base_op) \ - BOOST_ITERATOR_FACADE_INTEROP_HEAD(inline, op, result_type) \ - { \ - /* For those compilers that do not support enable_if */ \ - BOOST_STATIC_ASSERT(( \ - is_interoperable< Derived1, Derived2 >::value \ - )); \ - return_prefix iterator_core_access::base_op( \ - *static_cast<Derived1 const*>(&lhs) \ - , *static_cast<Derived2 const*>(&rhs) \ - , BOOST_ITERATOR_CONVERTIBLE(Derived2,Derived1) \ - ); \ - } - -# define BOOST_ITERATOR_FACADE_RELATION(op, return_prefix, base_op) \ - BOOST_ITERATOR_FACADE_INTEROP( \ - op \ - , boost::iterators::detail::always_bool2 \ - , return_prefix \ - , base_op \ - ) - - BOOST_ITERATOR_FACADE_RELATION(==, return, equal) - BOOST_ITERATOR_FACADE_RELATION(!=, return !, equal) - -# undef BOOST_ITERATOR_FACADE_RELATION - - -# define BOOST_ITERATOR_FACADE_INTEROP_RANDOM_ACCESS(op, result_type, return_prefix, base_op) \ - BOOST_ITERATOR_FACADE_INTEROP_RANDOM_ACCESS_HEAD(inline, op, result_type) \ - { \ - /* For those compilers that do not support enable_if */ \ - BOOST_STATIC_ASSERT(( \ - is_interoperable< Derived1, Derived2 >::value && \ - boost::iterators::detail::is_traversal_at_least< typename iterator_category< Derived1 >::type, random_access_traversal_tag >::value && \ - boost::iterators::detail::is_traversal_at_least< typename iterator_category< Derived2 >::type, random_access_traversal_tag >::value \ - )); \ - return_prefix iterator_core_access::base_op( \ - *static_cast<Derived1 const*>(&lhs) \ - , *static_cast<Derived2 const*>(&rhs) \ - , BOOST_ITERATOR_CONVERTIBLE(Derived2,Derived1) \ - ); \ - } - -# define BOOST_ITERATOR_FACADE_RANDOM_ACCESS_RELATION(op, return_prefix, base_op) \ - BOOST_ITERATOR_FACADE_INTEROP_RANDOM_ACCESS( \ - op \ - , boost::iterators::detail::always_bool2 \ - , return_prefix \ - , base_op \ - ) - - BOOST_ITERATOR_FACADE_RANDOM_ACCESS_RELATION(<, return 0 >, distance_from) - BOOST_ITERATOR_FACADE_RANDOM_ACCESS_RELATION(>, return 0 <, distance_from) - BOOST_ITERATOR_FACADE_RANDOM_ACCESS_RELATION(<=, return 0 >=, distance_from) - BOOST_ITERATOR_FACADE_RANDOM_ACCESS_RELATION(>=, return 0 <=, distance_from) - -# undef BOOST_ITERATOR_FACADE_RANDOM_ACCESS_RELATION - - // operator- requires an additional part in the static assertion - BOOST_ITERATOR_FACADE_INTEROP_RANDOM_ACCESS( - - - , boost::iterators::detail::choose_difference_type - , return - , distance_from - ) - -# undef BOOST_ITERATOR_FACADE_INTEROP -# undef BOOST_ITERATOR_FACADE_INTEROP_RANDOM_ACCESS - -# define BOOST_ITERATOR_FACADE_PLUS(args) \ - BOOST_ITERATOR_FACADE_PLUS_HEAD(inline, args) \ - { \ - Derived tmp(static_cast<Derived const&>(i)); \ - return tmp += n; \ - } - - BOOST_ITERATOR_FACADE_PLUS(( - iterator_facade<Derived, V, TC, R, D> const& i - , typename Derived::difference_type n - )) - - BOOST_ITERATOR_FACADE_PLUS(( - typename Derived::difference_type n - , iterator_facade<Derived, V, TC, R, D> const& i - )) - -# undef BOOST_ITERATOR_FACADE_PLUS -# undef BOOST_ITERATOR_FACADE_PLUS_HEAD - -# undef BOOST_ITERATOR_FACADE_INTEROP_HEAD -# undef BOOST_ITERATOR_FACADE_INTEROP_RANDOM_ACCESS_HEAD -# undef BOOST_ITERATOR_FACADE_INTEROP_HEAD_IMPL - -} // namespace iterators - -using iterators::iterator_core_access; -using iterators::iterator_facade; - -} // namespace boost - -#include <boost/iterator/detail/config_undef.hpp> - -#endif // BOOST_ITERATOR_FACADE_23022003THW_HPP +// (C) Copyright David Abrahams 2002.
+// (C) Copyright Jeremy Siek 2002.
+// (C) Copyright Thomas Witt 2002.
+// 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_ITERATOR_FACADE_23022003THW_HPP
+#define BOOST_ITERATOR_FACADE_23022003THW_HPP
+
+#include <boost/config.hpp>
+#include <boost/iterator.hpp>
+#include <boost/iterator/interoperable.hpp>
+#include <boost/iterator/iterator_traits.hpp>
+#include <boost/iterator/iterator_categories.hpp>
+
+#include <boost/iterator/detail/facade_iterator_category.hpp>
+#include <boost/iterator/detail/enable_if.hpp>
+
+#include <boost/static_assert.hpp>
+#include <boost/utility/addressof.hpp>
+
+#include <boost/type_traits/is_same.hpp>
+#include <boost/type_traits/add_const.hpp>
+#include <boost/type_traits/add_pointer.hpp>
+#include <boost/type_traits/add_lvalue_reference.hpp>
+#include <boost/type_traits/remove_const.hpp>
+#include <boost/type_traits/remove_reference.hpp>
+#include <boost/type_traits/is_convertible.hpp>
+#include <boost/type_traits/is_pod.hpp>
+
+#include <boost/mpl/eval_if.hpp>
+#include <boost/mpl/if.hpp>
+#include <boost/mpl/or.hpp>
+#include <boost/mpl/and.hpp>
+#include <boost/mpl/not.hpp>
+#include <boost/mpl/always.hpp>
+#include <boost/mpl/apply.hpp>
+#include <boost/mpl/identity.hpp>
+
+#include <boost/iterator/detail/config_def.hpp> // this goes last
+
+namespace boost {
+namespace iterators {
+
+ // This forward declaration is required for the friend declaration
+ // in iterator_core_access
+ template <class I, class V, class TC, class R, class D> class iterator_facade;
+
+ namespace detail
+ {
+ // A binary metafunction class that always returns bool. VC6
+ // ICEs on mpl::always<bool>, probably because of the default
+ // parameters.
+ struct always_bool2
+ {
+ template <class T, class U>
+ struct apply
+ {
+ typedef bool type;
+ };
+ };
+
+ // The type trait checks if the category or traversal is at least as advanced as the specified required traversal
+ template< typename CategoryOrTraversal, typename Required >
+ struct is_traversal_at_least :
+ public boost::is_convertible< typename iterator_category_to_traversal< CategoryOrTraversal >::type, Required >
+ {};
+
+ //
+ // enable if for use in operator implementation.
+ //
+ template <
+ class Facade1
+ , class Facade2
+ , class Return
+ >
+ struct enable_if_interoperable :
+ public boost::iterators::enable_if<
+ is_interoperable< Facade1, Facade2 >
+ , Return
+ >
+ {};
+
+ //
+ // enable if for use in implementation of operators specific for random access traversal.
+ //
+ template <
+ class Facade1
+ , class Facade2
+ , class Return
+ >
+ struct enable_if_interoperable_and_random_access_traversal :
+ public boost::iterators::enable_if<
+ mpl::and_<
+ is_interoperable< Facade1, Facade2 >
+ , is_traversal_at_least< typename iterator_category< Facade1 >::type, random_access_traversal_tag >
+ , is_traversal_at_least< typename iterator_category< Facade2 >::type, random_access_traversal_tag >
+ >
+ , Return
+ >
+ {};
+
+ //
+ // Generates associated types for an iterator_facade with the
+ // given parameters.
+ //
+ template <
+ class ValueParam
+ , class CategoryOrTraversal
+ , class Reference
+ , class Difference
+ >
+ struct iterator_facade_types
+ {
+ typedef typename facade_iterator_category<
+ CategoryOrTraversal, ValueParam, Reference
+ >::type iterator_category;
+
+ typedef typename remove_const<ValueParam>::type value_type;
+
+ // Not the real associated pointer type
+ typedef typename mpl::eval_if<
+ boost::iterators::detail::iterator_writability_disabled<ValueParam,Reference>
+ , add_pointer<const value_type>
+ , add_pointer<value_type>
+ >::type pointer;
+
+# if defined(BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION) \
+ && (BOOST_WORKAROUND(_STLPORT_VERSION, BOOST_TESTED_AT(0x452)) \
+ || BOOST_WORKAROUND(BOOST_DINKUMWARE_STDLIB, BOOST_TESTED_AT(310))) \
+ || BOOST_WORKAROUND(BOOST_RWSTD_VER, BOOST_TESTED_AT(0x20101)) \
+ || BOOST_WORKAROUND(BOOST_DINKUMWARE_STDLIB, <= 310)
+
+ // To interoperate with some broken library/compiler
+ // combinations, user-defined iterators must be derived from
+ // std::iterator. It is possible to implement a standard
+ // library for broken compilers without this limitation.
+# define BOOST_ITERATOR_FACADE_NEEDS_ITERATOR_BASE 1
+
+ typedef
+ iterator<iterator_category, value_type, Difference, pointer, Reference>
+ base;
+# endif
+ };
+
+ // iterators whose dereference operators reference the same value
+ // for all iterators into the same sequence (like many input
+ // iterators) need help with their postfix ++: the referenced
+ // value must be read and stored away before the increment occurs
+ // so that *a++ yields the originally referenced element and not
+ // the next one.
+ template <class Iterator>
+ class postfix_increment_proxy
+ {
+ typedef typename iterator_value<Iterator>::type value_type;
+ public:
+ explicit postfix_increment_proxy(Iterator const& x)
+ : stored_value(*x)
+ {}
+
+ // Returning a mutable reference allows nonsense like
+ // (*r++).mutate(), but it imposes fewer assumptions about the
+ // behavior of the value_type. In particular, recall that
+ // (*r).mutate() is legal if operator* returns by value.
+ value_type&
+ operator*() const
+ {
+ return this->stored_value;
+ }
+ private:
+ mutable value_type stored_value;
+ };
+
+ //
+ // In general, we can't determine that such an iterator isn't
+ // writable -- we also need to store a copy of the old iterator so
+ // that it can be written into.
+ template <class Iterator>
+ class writable_postfix_increment_proxy
+ {
+ typedef typename iterator_value<Iterator>::type value_type;
+ public:
+ explicit writable_postfix_increment_proxy(Iterator const& x)
+ : stored_value(*x)
+ , stored_iterator(x)
+ {}
+
+ // Dereferencing must return a proxy so that both *r++ = o and
+ // value_type(*r++) can work. In this case, *r is the same as
+ // *r++, and the conversion operator below is used to ensure
+ // readability.
+ writable_postfix_increment_proxy const&
+ operator*() const
+ {
+ return *this;
+ }
+
+ // Provides readability of *r++
+ operator value_type&() const
+ {
+ return stored_value;
+ }
+
+ // Provides writability of *r++
+ template <class T>
+ T const& operator=(T const& x) const
+ {
+ *this->stored_iterator = x;
+ return x;
+ }
+
+ // This overload just in case only non-const objects are writable
+ template <class T>
+ T& operator=(T& x) const
+ {
+ *this->stored_iterator = x;
+ return x;
+ }
+
+ // Provides X(r++)
+ operator Iterator const&() const
+ {
+ return stored_iterator;
+ }
+
+ private:
+ mutable value_type stored_value;
+ Iterator stored_iterator;
+ };
+
+# ifdef BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION
+
+ template <class Reference, class Value>
+ struct is_non_proxy_reference_impl
+ {
+ static Reference r;
+
+ template <class R>
+ static typename mpl::if_<
+ is_convertible<
+ R const volatile*
+ , Value const volatile*
+ >
+ , char[1]
+ , char[2]
+ >::type& helper(R const&);
+
+ BOOST_STATIC_CONSTANT(bool, value = sizeof(helper(r)) == 1);
+ };
+
+ template <class Reference, class Value>
+ struct is_non_proxy_reference
+ : mpl::bool_<
+ is_non_proxy_reference_impl<Reference, Value>::value
+ >
+ {};
+# else
+ template <class Reference, class Value>
+ struct is_non_proxy_reference
+ : is_convertible<
+ typename remove_reference<Reference>::type
+ const volatile*
+ , Value const volatile*
+ >
+ {};
+# endif
+
+ // A metafunction to choose the result type of postfix ++
+ //
+ // Because the C++98 input iterator requirements say that *r++ has
+ // type T (value_type), implementations of some standard
+ // algorithms like lexicographical_compare may use constructions
+ // like:
+ //
+ // *r++ < *s++
+ //
+ // If *r++ returns a proxy (as required if r is writable but not
+ // multipass), this sort of expression will fail unless the proxy
+ // supports the operator<. Since there are any number of such
+ // operations, we're not going to try to support them. Therefore,
+ // even if r++ returns a proxy, *r++ will only return a proxy if
+ // *r also returns a proxy.
+ template <class Iterator, class Value, class Reference, class CategoryOrTraversal>
+ struct postfix_increment_result
+ : mpl::eval_if<
+ mpl::and_<
+ // A proxy is only needed for readable iterators
+ is_convertible<
+ Reference
+ // Use add_lvalue_reference to form `reference to Value` due to
+ // some (strict) C++03 compilers (e.g. `gcc -std=c++03`) reject
+ // 'reference-to-reference' in the template which described in CWG
+ // DR106.
+ // http://www.open-std.org/Jtc1/sc22/wg21/docs/cwg_defects.html#106
+ , typename add_lvalue_reference<Value const>::type
+ >
+
+ // No multipass iterator can have values that disappear
+ // before positions can be re-visited
+ , mpl::not_<
+ is_convertible<
+ typename iterator_category_to_traversal<CategoryOrTraversal>::type
+ , forward_traversal_tag
+ >
+ >
+ >
+ , mpl::if_<
+ is_non_proxy_reference<Reference,Value>
+ , postfix_increment_proxy<Iterator>
+ , writable_postfix_increment_proxy<Iterator>
+ >
+ , mpl::identity<Iterator>
+ >
+ {};
+
+ // operator->() needs special support for input iterators to strictly meet the
+ // standard's requirements. If *i is not a reference type, we must still
+ // produce an lvalue to which a pointer can be formed. We do that by
+ // returning a proxy object containing an instance of the reference object.
+ template <class Reference, class Pointer>
+ struct operator_arrow_dispatch // proxy references
+ {
+ struct proxy
+ {
+ explicit proxy(Reference const & x) : m_ref(x) {}
+ Reference* operator->() { return boost::addressof(m_ref); }
+ // This function is needed for MWCW and BCC, which won't call
+ // operator-> again automatically per 13.3.1.2 para 8
+ operator Reference*() { return boost::addressof(m_ref); }
+ Reference m_ref;
+ };
+ typedef proxy result_type;
+ static result_type apply(Reference const & x)
+ {
+ return result_type(x);
+ }
+ };
+
+ template <class T, class Pointer>
+ struct operator_arrow_dispatch<T&, Pointer> // "real" references
+ {
+ typedef Pointer result_type;
+ static result_type apply(T& x)
+ {
+ return boost::addressof(x);
+ }
+ };
+
+ // A proxy return type for operator[], needed to deal with
+ // iterators that may invalidate referents upon destruction.
+ // Consider the temporary iterator in *(a + n)
+ template <class Iterator>
+ class operator_brackets_proxy
+ {
+ // Iterator is actually an iterator_facade, so we do not have to
+ // go through iterator_traits to access the traits.
+ typedef typename Iterator::reference reference;
+ typedef typename Iterator::value_type value_type;
+
+ public:
+ operator_brackets_proxy(Iterator const& iter)
+ : m_iter(iter)
+ {}
+
+ operator reference() const
+ {
+ return *m_iter;
+ }
+
+ operator_brackets_proxy& operator=(value_type const& val)
+ {
+ *m_iter = val;
+ return *this;
+ }
+
+ private:
+ Iterator m_iter;
+ };
+
+ // A metafunction that determines whether operator[] must return a
+ // proxy, or whether it can simply return a copy of the value_type.
+ template <class ValueType, class Reference>
+ struct use_operator_brackets_proxy
+ : mpl::not_<
+ mpl::and_<
+ // Really we want an is_copy_constructible trait here,
+ // but is_POD will have to suffice in the meantime.
+ boost::is_POD<ValueType>
+ , iterator_writability_disabled<ValueType,Reference>
+ >
+ >
+ {};
+
+ template <class Iterator, class Value, class Reference>
+ struct operator_brackets_result
+ {
+ typedef typename mpl::if_<
+ use_operator_brackets_proxy<Value,Reference>
+ , operator_brackets_proxy<Iterator>
+ , Value
+ >::type type;
+ };
+
+ template <class Iterator>
+ operator_brackets_proxy<Iterator> make_operator_brackets_result(Iterator const& iter, mpl::true_)
+ {
+ return operator_brackets_proxy<Iterator>(iter);
+ }
+
+ template <class Iterator>
+ typename Iterator::value_type make_operator_brackets_result(Iterator const& iter, mpl::false_)
+ {
+ return *iter;
+ }
+
+ struct choose_difference_type
+ {
+ template <class I1, class I2>
+ struct apply
+ :
+# ifdef BOOST_NO_ONE_WAY_ITERATOR_INTEROP
+ iterator_difference<I1>
+# else
+ mpl::eval_if<
+ is_convertible<I2,I1>
+ , iterator_difference<I1>
+ , iterator_difference<I2>
+ >
+# endif
+ {};
+
+ };
+
+ template <
+ class Derived
+ , class Value
+ , class CategoryOrTraversal
+ , class Reference
+ , class Difference
+ , bool IsBidirectionalTraversal
+ , bool IsRandomAccessTraversal
+ >
+ class iterator_facade_base;
+
+ } // namespace detail
+
+
+ // Macros which describe the declarations of binary operators
+# ifdef BOOST_NO_STRICT_ITERATOR_INTEROPERABILITY
+# define BOOST_ITERATOR_FACADE_INTEROP_HEAD_IMPL(prefix, op, result_type, enabler) \
+ template < \
+ class Derived1, class V1, class TC1, class Reference1, class Difference1 \
+ , class Derived2, class V2, class TC2, class Reference2, class Difference2 \
+ > \
+ prefix typename mpl::apply2<result_type,Derived1,Derived2>::type \
+ operator op( \
+ iterator_facade<Derived1, V1, TC1, Reference1, Difference1> const& lhs \
+ , iterator_facade<Derived2, V2, TC2, Reference2, Difference2> const& rhs)
+# else
+# define BOOST_ITERATOR_FACADE_INTEROP_HEAD_IMPL(prefix, op, result_type, enabler) \
+ template < \
+ class Derived1, class V1, class TC1, class Reference1, class Difference1 \
+ , class Derived2, class V2, class TC2, class Reference2, class Difference2 \
+ > \
+ prefix typename enabler< \
+ Derived1, Derived2 \
+ , typename mpl::apply2<result_type,Derived1,Derived2>::type \
+ >::type \
+ operator op( \
+ iterator_facade<Derived1, V1, TC1, Reference1, Difference1> const& lhs \
+ , iterator_facade<Derived2, V2, TC2, Reference2, Difference2> const& rhs)
+# endif
+
+# define BOOST_ITERATOR_FACADE_INTEROP_HEAD(prefix, op, result_type) \
+ BOOST_ITERATOR_FACADE_INTEROP_HEAD_IMPL(prefix, op, result_type, boost::iterators::detail::enable_if_interoperable)
+
+# define BOOST_ITERATOR_FACADE_INTEROP_RANDOM_ACCESS_HEAD(prefix, op, result_type) \
+ BOOST_ITERATOR_FACADE_INTEROP_HEAD_IMPL(prefix, op, result_type, boost::iterators::detail::enable_if_interoperable_and_random_access_traversal)
+
+# define BOOST_ITERATOR_FACADE_PLUS_HEAD(prefix,args) \
+ template <class Derived, class V, class TC, class R, class D> \
+ prefix typename boost::iterators::enable_if< \
+ boost::iterators::detail::is_traversal_at_least< TC, boost::iterators::random_access_traversal_tag >, \
+ Derived \
+ >::type operator+ args
+
+ //
+ // Helper class for granting access to the iterator core interface.
+ //
+ // The simple core interface is used by iterator_facade. The core
+ // interface of a user/library defined iterator type should not be made public
+ // so that it does not clutter the public interface. Instead iterator_core_access
+ // should be made friend so that iterator_facade can access the core
+ // interface through iterator_core_access.
+ //
+ class iterator_core_access
+ {
+# if defined(BOOST_NO_MEMBER_TEMPLATE_FRIENDS)
+ // Tasteless as this may seem, making all members public allows member templates
+ // to work in the absence of member template friends.
+ public:
+# else
+
+ template <class I, class V, class TC, class R, class D> friend class iterator_facade;
+ template <class I, class V, class TC, class R, class D, bool IsBidirectionalTraversal, bool IsRandomAccessTraversal>
+ friend class detail::iterator_facade_base;
+
+# define BOOST_ITERATOR_FACADE_RELATION(op) \
+ BOOST_ITERATOR_FACADE_INTEROP_HEAD(friend,op, boost::iterators::detail::always_bool2);
+
+ BOOST_ITERATOR_FACADE_RELATION(==)
+ BOOST_ITERATOR_FACADE_RELATION(!=)
+
+# undef BOOST_ITERATOR_FACADE_RELATION
+
+# define BOOST_ITERATOR_FACADE_RANDOM_ACCESS_RELATION(op) \
+ BOOST_ITERATOR_FACADE_INTEROP_RANDOM_ACCESS_HEAD(friend,op, boost::iterators::detail::always_bool2);
+
+ BOOST_ITERATOR_FACADE_RANDOM_ACCESS_RELATION(<)
+ BOOST_ITERATOR_FACADE_RANDOM_ACCESS_RELATION(>)
+ BOOST_ITERATOR_FACADE_RANDOM_ACCESS_RELATION(<=)
+ BOOST_ITERATOR_FACADE_RANDOM_ACCESS_RELATION(>=)
+
+# undef BOOST_ITERATOR_FACADE_RANDOM_ACCESS_RELATION
+
+ BOOST_ITERATOR_FACADE_INTEROP_RANDOM_ACCESS_HEAD(
+ friend, -, boost::iterators::detail::choose_difference_type)
+ ;
+
+ BOOST_ITERATOR_FACADE_PLUS_HEAD(
+ friend inline
+ , (iterator_facade<Derived, V, TC, R, D> const&
+ , typename Derived::difference_type)
+ )
+ ;
+
+ BOOST_ITERATOR_FACADE_PLUS_HEAD(
+ friend inline
+ , (typename Derived::difference_type
+ , iterator_facade<Derived, V, TC, R, D> const&)
+ )
+ ;
+
+# endif
+
+ template <class Facade>
+ static typename Facade::reference dereference(Facade const& f)
+ {
+ return f.dereference();
+ }
+
+ template <class Facade>
+ static void increment(Facade& f)
+ {
+ f.increment();
+ }
+
+ template <class Facade>
+ static void decrement(Facade& f)
+ {
+ f.decrement();
+ }
+
+ template <class Facade1, class Facade2>
+ static bool equal(Facade1 const& f1, Facade2 const& f2, mpl::true_)
+ {
+ return f1.equal(f2);
+ }
+
+ template <class Facade1, class Facade2>
+ static bool equal(Facade1 const& f1, Facade2 const& f2, mpl::false_)
+ {
+ return f2.equal(f1);
+ }
+
+ template <class Facade>
+ static void advance(Facade& f, typename Facade::difference_type n)
+ {
+ f.advance(n);
+ }
+
+ template <class Facade1, class Facade2>
+ static typename Facade1::difference_type distance_from(
+ Facade1 const& f1, Facade2 const& f2, mpl::true_)
+ {
+ return -f1.distance_to(f2);
+ }
+
+ template <class Facade1, class Facade2>
+ static typename Facade2::difference_type distance_from(
+ Facade1 const& f1, Facade2 const& f2, mpl::false_)
+ {
+ return f2.distance_to(f1);
+ }
+
+ //
+ // Curiously Recurring Template interface.
+ //
+ template <class I, class V, class TC, class R, class D>
+ static I& derived(iterator_facade<I,V,TC,R,D>& facade)
+ {
+ return *static_cast<I*>(&facade);
+ }
+
+ template <class I, class V, class TC, class R, class D>
+ static I const& derived(iterator_facade<I,V,TC,R,D> const& facade)
+ {
+ return *static_cast<I const*>(&facade);
+ }
+
+ // objects of this class are useless
+ BOOST_DELETED_FUNCTION(iterator_core_access())
+ };
+
+ namespace detail {
+
+ // Implementation for forward traversal iterators
+ template <
+ class Derived
+ , class Value
+ , class CategoryOrTraversal
+ , class Reference
+ , class Difference
+ >
+ class iterator_facade_base< Derived, Value, CategoryOrTraversal, Reference, Difference, false, false >
+# ifdef BOOST_ITERATOR_FACADE_NEEDS_ITERATOR_BASE
+ : public boost::iterators::detail::iterator_facade_types<
+ Value, CategoryOrTraversal, Reference, Difference
+ >::base
+# undef BOOST_ITERATOR_FACADE_NEEDS_ITERATOR_BASE
+# endif
+ {
+ private:
+ typedef boost::iterators::detail::iterator_facade_types<
+ Value, CategoryOrTraversal, Reference, Difference
+ > associated_types;
+
+ typedef boost::iterators::detail::operator_arrow_dispatch<
+ Reference
+ , typename associated_types::pointer
+ > operator_arrow_dispatch_;
+
+ public:
+ typedef typename associated_types::value_type value_type;
+ typedef Reference reference;
+ typedef Difference difference_type;
+
+ typedef typename operator_arrow_dispatch_::result_type pointer;
+
+ typedef typename associated_types::iterator_category iterator_category;
+
+ public:
+ reference operator*() const
+ {
+ return iterator_core_access::dereference(this->derived());
+ }
+
+ pointer operator->() const
+ {
+ return operator_arrow_dispatch_::apply(*this->derived());
+ }
+
+ Derived& operator++()
+ {
+ iterator_core_access::increment(this->derived());
+ return this->derived();
+ }
+
+ protected:
+ //
+ // Curiously Recurring Template interface.
+ //
+ Derived& derived()
+ {
+ return *static_cast<Derived*>(this);
+ }
+
+ Derived const& derived() const
+ {
+ return *static_cast<Derived const*>(this);
+ }
+ };
+
+ // Implementation for bidirectional traversal iterators
+ template <
+ class Derived
+ , class Value
+ , class CategoryOrTraversal
+ , class Reference
+ , class Difference
+ >
+ class iterator_facade_base< Derived, Value, CategoryOrTraversal, Reference, Difference, true, false > :
+ public iterator_facade_base< Derived, Value, CategoryOrTraversal, Reference, Difference, false, false >
+ {
+ public:
+ Derived& operator--()
+ {
+ iterator_core_access::decrement(this->derived());
+ return this->derived();
+ }
+
+ Derived operator--(int)
+ {
+ Derived tmp(this->derived());
+ --*this;
+ return tmp;
+ }
+ };
+
+ // Implementation for random access traversal iterators
+ template <
+ class Derived
+ , class Value
+ , class CategoryOrTraversal
+ , class Reference
+ , class Difference
+ >
+ class iterator_facade_base< Derived, Value, CategoryOrTraversal, Reference, Difference, true, true > :
+ public iterator_facade_base< Derived, Value, CategoryOrTraversal, Reference, Difference, true, false >
+ {
+ private:
+ typedef iterator_facade_base< Derived, Value, CategoryOrTraversal, Reference, Difference, true, false > base_type;
+
+ public:
+ typedef typename base_type::reference reference;
+ typedef typename base_type::difference_type difference_type;
+
+ public:
+ typename boost::iterators::detail::operator_brackets_result<Derived, Value, reference>::type
+ operator[](difference_type n) const
+ {
+ typedef boost::iterators::detail::use_operator_brackets_proxy<Value, Reference> use_proxy;
+
+ return boost::iterators::detail::make_operator_brackets_result<Derived>(
+ this->derived() + n
+ , use_proxy()
+ );
+ }
+
+ Derived& operator+=(difference_type n)
+ {
+ iterator_core_access::advance(this->derived(), n);
+ return this->derived();
+ }
+
+ Derived& operator-=(difference_type n)
+ {
+ iterator_core_access::advance(this->derived(), -n);
+ return this->derived();
+ }
+
+ Derived operator-(difference_type x) const
+ {
+ Derived result(this->derived());
+ return result -= x;
+ }
+ };
+
+ } // namespace detail
+
+ //
+ // iterator_facade - use as a public base class for defining new
+ // standard-conforming iterators.
+ //
+ template <
+ class Derived // The derived iterator type being constructed
+ , class Value
+ , class CategoryOrTraversal
+ , class Reference = Value&
+ , class Difference = std::ptrdiff_t
+ >
+ class iterator_facade :
+ public detail::iterator_facade_base<
+ Derived,
+ Value,
+ CategoryOrTraversal,
+ Reference,
+ Difference,
+ detail::is_traversal_at_least< CategoryOrTraversal, bidirectional_traversal_tag >::value,
+ detail::is_traversal_at_least< CategoryOrTraversal, random_access_traversal_tag >::value
+ >
+ {
+ protected:
+ // For use by derived classes
+ typedef iterator_facade<Derived,Value,CategoryOrTraversal,Reference,Difference> iterator_facade_;
+ };
+
+ template <class I, class V, class TC, class R, class D>
+ inline typename boost::iterators::detail::postfix_increment_result<I,V,R,TC>::type
+ operator++(
+ iterator_facade<I,V,TC,R,D>& i
+ , int
+ )
+ {
+ typename boost::iterators::detail::postfix_increment_result<I,V,R,TC>::type
+ tmp(*static_cast<I*>(&i));
+
+ ++i;
+
+ return tmp;
+ }
+
+
+ //
+ // Comparison operator implementation. The library supplied operators
+ // enables the user to provide fully interoperable constant/mutable
+ // iterator types. I.e. the library provides all operators
+ // for all mutable/constant iterator combinations.
+ //
+ // Note though that this kind of interoperability for constant/mutable
+ // iterators is not required by the standard for container iterators.
+ // All the standard asks for is a conversion mutable -> constant.
+ // Most standard library implementations nowadays provide fully interoperable
+ // iterator implementations, but there are still heavily used implementations
+ // that do not provide them. (Actually it's even worse, they do not provide
+ // them for only a few iterators.)
+ //
+ // ?? Maybe a BOOST_ITERATOR_NO_FULL_INTEROPERABILITY macro should
+ // enable the user to turn off mixed type operators
+ //
+ // The library takes care to provide only the right operator overloads.
+ // I.e.
+ //
+ // bool operator==(Iterator, Iterator);
+ // bool operator==(ConstIterator, Iterator);
+ // bool operator==(Iterator, ConstIterator);
+ // bool operator==(ConstIterator, ConstIterator);
+ //
+ // ...
+ //
+ // In order to do so it uses c++ idioms that are not yet widely supported
+ // by current compiler releases. The library is designed to degrade gracefully
+ // in the face of compiler deficiencies. In general compiler
+ // deficiencies result in less strict error checking and more obscure
+ // error messages, functionality is not affected.
+ //
+ // For full operation compiler support for "Substitution Failure Is Not An Error"
+ // (aka. enable_if) and boost::is_convertible is required.
+ //
+ // The following problems occur if support is lacking.
+ //
+ // Pseudo code
+ //
+ // ---------------
+ // AdaptorA<Iterator1> a1;
+ // AdaptorA<Iterator2> a2;
+ //
+ // // This will result in a no such overload error in full operation
+ // // If enable_if or is_convertible is not supported
+ // // The instantiation will fail with an error hopefully indicating that
+ // // there is no operator== for Iterator1, Iterator2
+ // // The same will happen if no enable_if is used to remove
+ // // false overloads from the templated conversion constructor
+ // // of AdaptorA.
+ //
+ // a1 == a2;
+ // ----------------
+ //
+ // AdaptorA<Iterator> a;
+ // AdaptorB<Iterator> b;
+ //
+ // // This will result in a no such overload error in full operation
+ // // If enable_if is not supported the static assert used
+ // // in the operator implementation will fail.
+ // // This will accidently work if is_convertible is not supported.
+ //
+ // a == b;
+ // ----------------
+ //
+
+# ifdef BOOST_NO_ONE_WAY_ITERATOR_INTEROP
+# define BOOST_ITERATOR_CONVERTIBLE(a,b) mpl::true_()
+# else
+# define BOOST_ITERATOR_CONVERTIBLE(a,b) is_convertible<a,b>()
+# endif
+
+# define BOOST_ITERATOR_FACADE_INTEROP(op, result_type, return_prefix, base_op) \
+ BOOST_ITERATOR_FACADE_INTEROP_HEAD(inline, op, result_type) \
+ { \
+ /* For those compilers that do not support enable_if */ \
+ BOOST_STATIC_ASSERT(( \
+ is_interoperable< Derived1, Derived2 >::value \
+ )); \
+ return_prefix iterator_core_access::base_op( \
+ *static_cast<Derived1 const*>(&lhs) \
+ , *static_cast<Derived2 const*>(&rhs) \
+ , BOOST_ITERATOR_CONVERTIBLE(Derived2,Derived1) \
+ ); \
+ }
+
+# define BOOST_ITERATOR_FACADE_RELATION(op, return_prefix, base_op) \
+ BOOST_ITERATOR_FACADE_INTEROP( \
+ op \
+ , boost::iterators::detail::always_bool2 \
+ , return_prefix \
+ , base_op \
+ )
+
+ BOOST_ITERATOR_FACADE_RELATION(==, return, equal)
+ BOOST_ITERATOR_FACADE_RELATION(!=, return !, equal)
+
+# undef BOOST_ITERATOR_FACADE_RELATION
+
+
+# define BOOST_ITERATOR_FACADE_INTEROP_RANDOM_ACCESS(op, result_type, return_prefix, base_op) \
+ BOOST_ITERATOR_FACADE_INTEROP_RANDOM_ACCESS_HEAD(inline, op, result_type) \
+ { \
+ /* For those compilers that do not support enable_if */ \
+ BOOST_STATIC_ASSERT(( \
+ is_interoperable< Derived1, Derived2 >::value && \
+ boost::iterators::detail::is_traversal_at_least< typename iterator_category< Derived1 >::type, random_access_traversal_tag >::value && \
+ boost::iterators::detail::is_traversal_at_least< typename iterator_category< Derived2 >::type, random_access_traversal_tag >::value \
+ )); \
+ return_prefix iterator_core_access::base_op( \
+ *static_cast<Derived1 const*>(&lhs) \
+ , *static_cast<Derived2 const*>(&rhs) \
+ , BOOST_ITERATOR_CONVERTIBLE(Derived2,Derived1) \
+ ); \
+ }
+
+# define BOOST_ITERATOR_FACADE_RANDOM_ACCESS_RELATION(op, return_prefix, base_op) \
+ BOOST_ITERATOR_FACADE_INTEROP_RANDOM_ACCESS( \
+ op \
+ , boost::iterators::detail::always_bool2 \
+ , return_prefix \
+ , base_op \
+ )
+
+ BOOST_ITERATOR_FACADE_RANDOM_ACCESS_RELATION(<, return 0 >, distance_from)
+ BOOST_ITERATOR_FACADE_RANDOM_ACCESS_RELATION(>, return 0 <, distance_from)
+ BOOST_ITERATOR_FACADE_RANDOM_ACCESS_RELATION(<=, return 0 >=, distance_from)
+ BOOST_ITERATOR_FACADE_RANDOM_ACCESS_RELATION(>=, return 0 <=, distance_from)
+
+# undef BOOST_ITERATOR_FACADE_RANDOM_ACCESS_RELATION
+
+ // operator- requires an additional part in the static assertion
+ BOOST_ITERATOR_FACADE_INTEROP_RANDOM_ACCESS(
+ -
+ , boost::iterators::detail::choose_difference_type
+ , return
+ , distance_from
+ )
+
+# undef BOOST_ITERATOR_FACADE_INTEROP
+# undef BOOST_ITERATOR_FACADE_INTEROP_RANDOM_ACCESS
+
+# define BOOST_ITERATOR_FACADE_PLUS(args) \
+ BOOST_ITERATOR_FACADE_PLUS_HEAD(inline, args) \
+ { \
+ Derived tmp(static_cast<Derived const&>(i)); \
+ return tmp += n; \
+ }
+
+ BOOST_ITERATOR_FACADE_PLUS((
+ iterator_facade<Derived, V, TC, R, D> const& i
+ , typename Derived::difference_type n
+ ))
+
+ BOOST_ITERATOR_FACADE_PLUS((
+ typename Derived::difference_type n
+ , iterator_facade<Derived, V, TC, R, D> const& i
+ ))
+
+# undef BOOST_ITERATOR_FACADE_PLUS
+# undef BOOST_ITERATOR_FACADE_PLUS_HEAD
+
+# undef BOOST_ITERATOR_FACADE_INTEROP_HEAD
+# undef BOOST_ITERATOR_FACADE_INTEROP_RANDOM_ACCESS_HEAD
+# undef BOOST_ITERATOR_FACADE_INTEROP_HEAD_IMPL
+
+} // namespace iterators
+
+using iterators::iterator_core_access;
+using iterators::iterator_facade;
+
+} // namespace boost
+
+#include <boost/iterator/detail/config_undef.hpp>
+
+#endif // BOOST_ITERATOR_FACADE_23022003THW_HPP
|