Chris@16: // (C) Copyright David Abrahams 2002.
Chris@16: // Distributed under the Boost Software License, Version 1.0. (See
Chris@16: // accompanying file LICENSE_1_0.txt or copy at
Chris@16: // http://www.boost.org/LICENSE_1_0.txt)
Chris@16: 
Chris@16: // Boost versions of
Chris@16: //
Chris@16: //    std::iterator_traits<>::iterator_category
Chris@16: //    std::iterator_traits<>::difference_type
Chris@16: //    std::distance()
Chris@16: //
Chris@16: // ...for all compilers and iterators
Chris@16: //
Chris@16: // Additionally, if X is a pointer
Chris@16: //    std::iterator_traits<X>::pointer
Chris@16: 
Chris@16: // Otherwise, if partial specialization is supported or X is not a pointer
Chris@16: //    std::iterator_traits<X>::value_type
Chris@16: //    std::iterator_traits<X>::pointer
Chris@16: //    std::iterator_traits<X>::reference
Chris@16: //
Chris@16: // See http://www.boost.org for most recent version including documentation.
Chris@16: 
Chris@16: // Revision History
Chris@16: // 04 Mar 2001 - More attempted fixes for Intel C++ (David Abrahams)
Chris@16: // 03 Mar 2001 - Put all implementation into namespace
Chris@16: //               boost::detail::iterator_traits_. Some progress made on fixes
Chris@16: //               for Intel compiler. (David Abrahams)
Chris@16: // 02 Mar 2001 - Changed BOOST_MSVC to BOOST_MSVC_STD_ITERATOR in a few
Chris@16: //               places. (Jeremy Siek)
Chris@16: // 19 Feb 2001 - Improved workarounds for stock MSVC6; use yes_type and
Chris@16: //               no_type from type_traits.hpp; stopped trying to remove_cv
Chris@16: //               before detecting is_pointer, in honor of the new type_traits
Chris@16: //               semantics. (David Abrahams)
Chris@16: // 13 Feb 2001 - Make it work with nearly all standard-conforming iterators
Chris@16: //               under raw VC6. The one category remaining which will fail is
Chris@16: //               that of iterators derived from std::iterator but not
Chris@16: //               boost::iterator and which redefine difference_type.
Chris@16: // 11 Feb 2001 - Clean away code which can never be used (David Abrahams)
Chris@16: // 09 Feb 2001 - Always have a definition for each traits member, even if it
Chris@16: //               can't be properly deduced. These will be incomplete types in
Chris@16: //               some cases (undefined<void>), but it helps suppress MSVC errors
Chris@16: //               elsewhere (David Abrahams)
Chris@16: // 07 Feb 2001 - Support for more of the traits members where possible, making
Chris@16: //               this useful as a replacement for std::iterator_traits<T> when
Chris@16: //               used as a default template parameter.
Chris@16: // 06 Feb 2001 - Removed useless #includes of standard library headers
Chris@16: //               (David Abrahams)
Chris@16: 
Chris@16: #ifndef ITERATOR_DWA122600_HPP_
Chris@16: # define ITERATOR_DWA122600_HPP_
Chris@16: 
Chris@16: # include <boost/config.hpp>
Chris@16: # include <iterator>
Chris@16: 
Chris@16: // STLPort 4.0 and betas have a bug when debugging is enabled and there is no
Chris@16: // partial specialization: instead of an iterator_category typedef, the standard
Chris@16: // container iterators have _Iterator_category.
Chris@16: //
Chris@16: // Also, whether debugging is enabled or not, there is a broken specialization
Chris@16: // of std::iterator<output_iterator_tag,void,void,void,void> which has no
Chris@16: // typedefs but iterator_category.
Chris@16: # if defined(__SGI_STL_PORT)
Chris@16: 
Chris@16: #  if (__SGI_STL_PORT <= 0x410) && !defined(__STL_CLASS_PARTIAL_SPECIALIZATION) && defined(__STL_DEBUG)
Chris@16: #   define BOOST_BAD_CONTAINER_ITERATOR_CATEGORY_TYPEDEF
Chris@16: #  endif
Chris@16: 
Chris@16: #  define BOOST_BAD_OUTPUT_ITERATOR_SPECIALIZATION
Chris@16: 
Chris@16: # endif // STLPort <= 4.1b4 && no partial specialization
Chris@16: 
Chris@16: # if !defined(BOOST_NO_STD_ITERATOR_TRAITS)             \
Chris@16:   && !defined(BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION) \
Chris@16:   && !defined(BOOST_MSVC_STD_ITERATOR)
Chris@16:     
Chris@16: namespace boost { namespace detail {
Chris@16: 
Chris@16: // Define a new template so it can be specialized
Chris@16: template <class Iterator>
Chris@16: struct iterator_traits
Chris@16:     : std::iterator_traits<Iterator>
Chris@16: {};
Chris@16: using std::distance;
Chris@16: 
Chris@16: }} // namespace boost::detail
Chris@16: 
Chris@16: # else
Chris@16: 
Chris@16: #  if  !defined(BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION)  \
Chris@16:     && !defined(BOOST_MSVC_STD_ITERATOR)
Chris@16: 
Chris@16: // This is the case where everything conforms except BOOST_NO_STD_ITERATOR_TRAITS
Chris@16: 
Chris@16: namespace boost { namespace detail {
Chris@16: 
Chris@16: // Rogue Wave Standard Library fools itself into thinking partial
Chris@16: // specialization is missing on some platforms (e.g. Sun), so fails to
Chris@16: // supply iterator_traits!
Chris@16: template <class Iterator>
Chris@16: struct iterator_traits
Chris@16: {
Chris@16:     typedef typename Iterator::value_type value_type;
Chris@16:     typedef typename Iterator::reference reference;
Chris@16:     typedef typename Iterator::pointer pointer;
Chris@16:     typedef typename Iterator::difference_type difference_type;
Chris@16:     typedef typename Iterator::iterator_category iterator_category;
Chris@16: };
Chris@16: 
Chris@16: template <class T>
Chris@16: struct iterator_traits<T*>
Chris@16: {
Chris@16:     typedef T value_type;
Chris@16:     typedef T& reference;
Chris@16:     typedef T* pointer;
Chris@16:     typedef std::ptrdiff_t difference_type;
Chris@16:     typedef std::random_access_iterator_tag iterator_category;
Chris@16: };
Chris@16: 
Chris@16: template <class T>
Chris@16: struct iterator_traits<T const*>
Chris@16: {
Chris@16:     typedef T value_type;
Chris@16:     typedef T const& reference;
Chris@16:     typedef T const* pointer;
Chris@16:     typedef std::ptrdiff_t difference_type;
Chris@16:     typedef std::random_access_iterator_tag iterator_category;
Chris@16: };
Chris@16: 
Chris@16: }} // namespace boost::detail
Chris@16: 
Chris@16: #  else
Chris@16: 
Chris@16: # include <boost/type_traits/remove_const.hpp>
Chris@16: # include <boost/type_traits/detail/yes_no_type.hpp>
Chris@16: # include <boost/type_traits/is_pointer.hpp>
Chris@16: 
Chris@16: # ifdef BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION
Chris@16: #  include <boost/type_traits/is_same.hpp>
Chris@16: #  include <boost/type_traits/remove_pointer.hpp>
Chris@16: # endif
Chris@16: # ifdef BOOST_BAD_OUTPUT_ITERATOR_SPECIALIZATION
Chris@16: #  include <boost/type_traits/is_base_and_derived.hpp>
Chris@16: # endif
Chris@16: 
Chris@16: # include <boost/mpl/if.hpp>
Chris@16: # include <boost/mpl/has_xxx.hpp>
Chris@16: # include <cstddef>
Chris@16: 
Chris@16: // should be the last #include
Chris@16: # include "boost/type_traits/detail/bool_trait_def.hpp"
Chris@16: 
Chris@16: namespace boost { namespace detail {
Chris@16: 
Chris@16: BOOST_MPL_HAS_XXX_TRAIT_DEF(value_type)
Chris@16: BOOST_MPL_HAS_XXX_TRAIT_DEF(reference)
Chris@16: BOOST_MPL_HAS_XXX_TRAIT_DEF(pointer)
Chris@16: BOOST_MPL_HAS_XXX_TRAIT_DEF(difference_type)
Chris@16: BOOST_MPL_HAS_XXX_TRAIT_DEF(iterator_category)
Chris@16: 
Chris@16: // is_mutable_iterator --
Chris@16: //
Chris@16: //   A metafunction returning true iff T is a mutable iterator type
Chris@16: //   with a nested value_type. Will only work portably with iterators
Chris@16: //   whose operator* returns a reference, but that seems to be OK for
Chris@16: //   the iterators supplied by Dinkumware. Some input iterators may
Chris@16: //   compile-time if they arrive here, and if the compiler is strict
Chris@16: //   about not taking the address of an rvalue.
Chris@16: 
Chris@16: // This one detects ordinary mutable iterators - the result of
Chris@16: // operator* is convertible to the value_type.
Chris@16: template <class T>
Chris@16: type_traits::yes_type is_mutable_iterator_helper(T const*, BOOST_DEDUCED_TYPENAME T::value_type*);
Chris@16: 
Chris@16: // Since you can't take the address of an rvalue, the guts of
Chris@16: // is_mutable_iterator_impl will fail if we use &*t directly.  This
Chris@16: // makes sure we can still work with non-lvalue iterators.
Chris@16: template <class T> T* mutable_iterator_lvalue_helper(T& x);
Chris@16: int mutable_iterator_lvalue_helper(...);
Chris@16: 
Chris@16: 
Chris@16: // This one detects output iterators such as ostream_iterator which
Chris@16: // return references to themselves.
Chris@16: template <class T>
Chris@16: type_traits::yes_type is_mutable_iterator_helper(T const*, T const*);
Chris@16: 
Chris@16: type_traits::no_type is_mutable_iterator_helper(...);
Chris@16: 
Chris@16: template <class T>
Chris@16: struct is_mutable_iterator_impl
Chris@16: {
Chris@16:     static T t;
Chris@16:     
Chris@16:     BOOST_STATIC_CONSTANT(
Chris@16:         bool, value = sizeof(
Chris@16:             detail::is_mutable_iterator_helper(
Chris@16:                 (T*)0
Chris@16:               , mutable_iterator_lvalue_helper(*t) // like &*t
Chris@16:             ))
Chris@16:         == sizeof(type_traits::yes_type)
Chris@16:     );
Chris@16: };
Chris@16: 
Chris@16: BOOST_TT_AUX_BOOL_TRAIT_DEF1(
Chris@16:     is_mutable_iterator,T,::boost::detail::is_mutable_iterator_impl<T>::value)
Chris@16: 
Chris@16: 
Chris@16: // is_full_iterator_traits --
Chris@16: //
Chris@16: //   A metafunction returning true iff T has all the requisite nested
Chris@16: //   types to satisfy the requirements for a fully-conforming
Chris@16: //   iterator_traits implementation.
Chris@16: template <class T>
Chris@16: struct is_full_iterator_traits_impl
Chris@16: {
Chris@16:     enum { value = 
Chris@16:            has_value_type<T>::value 
Chris@16:            & has_reference<T>::value 
Chris@16:            & has_pointer<T>::value 
Chris@16:            & has_difference_type<T>::value
Chris@16:            & has_iterator_category<T>::value
Chris@16:     };
Chris@16: };
Chris@16: 
Chris@16: BOOST_TT_AUX_BOOL_TRAIT_DEF1(
Chris@16:     is_full_iterator_traits,T,::boost::detail::is_full_iterator_traits_impl<T>::value)
Chris@16: 
Chris@16: 
Chris@16: #   ifdef BOOST_BAD_CONTAINER_ITERATOR_CATEGORY_TYPEDEF
Chris@16: BOOST_MPL_HAS_XXX_TRAIT_DEF(_Iterator_category)
Chris@16:     
Chris@16: // is_stlport_40_debug_iterator --
Chris@16: //
Chris@16: //   A metafunction returning true iff T has all the requisite nested
Chris@16: //   types to satisfy the requirements of an STLPort 4.0 debug iterator
Chris@16: //   iterator_traits implementation.
Chris@16: template <class T>
Chris@16: struct is_stlport_40_debug_iterator_impl
Chris@16: {
Chris@16:     enum { value = 
Chris@16:            has_value_type<T>::value 
Chris@16:            & has_reference<T>::value 
Chris@16:            & has_pointer<T>::value 
Chris@16:            & has_difference_type<T>::value
Chris@16:            & has__Iterator_category<T>::value
Chris@16:     };
Chris@16: };
Chris@16: 
Chris@16: BOOST_TT_AUX_BOOL_TRAIT_DEF1(
Chris@16:     is_stlport_40_debug_iterator,T,::boost::detail::is_stlport_40_debug_iterator_impl<T>::value)
Chris@16: 
Chris@16: template <class T>
Chris@16: struct stlport_40_debug_iterator_traits
Chris@16: {
Chris@16:     typedef typename T::value_type value_type;
Chris@16:     typedef typename T::reference reference;
Chris@16:     typedef typename T::pointer pointer;
Chris@16:     typedef typename T::difference_type difference_type;
Chris@16:     typedef typename T::_Iterator_category iterator_category;
Chris@16: };
Chris@16: #   endif // BOOST_BAD_CONTAINER_ITERATOR_CATEGORY_TYPEDEF 
Chris@16: 
Chris@16: template <class T> struct pointer_iterator_traits;
Chris@16: 
Chris@16: #   ifndef BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION
Chris@16: template <class T>
Chris@16: struct pointer_iterator_traits<T*>
Chris@16: {
Chris@16:     typedef typename remove_const<T>::type value_type;
Chris@16:     typedef T* pointer;
Chris@16:     typedef T& reference;
Chris@16:     typedef std::random_access_iterator_tag iterator_category;
Chris@16:     typedef std::ptrdiff_t difference_type;
Chris@16: };
Chris@16: #   else
Chris@16: 
Chris@16: // In case of no template partial specialization, and if T is a
Chris@16: // pointer, iterator_traits<T>::value_type can still be computed.  For
Chris@16: // some basic types, remove_pointer is manually defined in
Chris@16: // type_traits/broken_compiler_spec.hpp. For others, do it yourself.
Chris@16: 
Chris@16: template<class P> class please_invoke_BOOST_TT_BROKEN_COMPILER_SPEC_on_cv_unqualified_pointee;
Chris@16: 
Chris@16: template<class P>
Chris@16: struct pointer_value_type
Chris@16:   : mpl::if_<
Chris@16:         is_same<P, typename remove_pointer<P>::type>
Chris@16:       , please_invoke_BOOST_TT_BROKEN_COMPILER_SPEC_on_cv_unqualified_pointee<P>
Chris@16:       , typename remove_const<
Chris@16:             typename remove_pointer<P>::type
Chris@16:         >::type
Chris@16:     >
Chris@16: {
Chris@16: };
Chris@16: 
Chris@16: 
Chris@16: template<class P>
Chris@16: struct pointer_reference
Chris@16:   : mpl::if_<
Chris@16:         is_same<P, typename remove_pointer<P>::type>
Chris@16:       , please_invoke_BOOST_TT_BROKEN_COMPILER_SPEC_on_cv_unqualified_pointee<P>
Chris@16:       , typename remove_pointer<P>::type&
Chris@16:     >
Chris@16: {
Chris@16: };
Chris@16: 
Chris@16: template <class T>
Chris@16: struct pointer_iterator_traits
Chris@16: {
Chris@16:     typedef T pointer;
Chris@16:     typedef std::random_access_iterator_tag iterator_category;
Chris@16:     typedef std::ptrdiff_t difference_type;
Chris@16: 
Chris@16:     typedef typename pointer_value_type<T>::type value_type;
Chris@16:     typedef typename pointer_reference<T>::type reference;
Chris@16: };
Chris@16: 
Chris@16: #   endif // BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION
Chris@16: 
Chris@16: // We'll sort iterator types into one of these classifications, from which we
Chris@16: // can determine the difference_type, pointer, reference, and value_type
Chris@16: template <class Iterator>
Chris@16: struct standard_iterator_traits
Chris@16: {
Chris@16:     typedef typename Iterator::difference_type difference_type;
Chris@16:     typedef typename Iterator::value_type value_type;
Chris@16:     typedef typename Iterator::pointer pointer;
Chris@16:     typedef typename Iterator::reference reference;
Chris@16:     typedef typename Iterator::iterator_category iterator_category;
Chris@16: };
Chris@16: 
Chris@16: template <class Iterator>
Chris@16: struct msvc_stdlib_mutable_traits
Chris@16:     : std::iterator_traits<Iterator>
Chris@16: {
Chris@16:     typedef typename std::iterator_traits<Iterator>::distance_type difference_type;
Chris@16:     typedef typename std::iterator_traits<Iterator>::value_type* pointer;
Chris@16:     typedef typename std::iterator_traits<Iterator>::value_type& reference;
Chris@16: };
Chris@16: 
Chris@16: template <class Iterator>
Chris@16: struct msvc_stdlib_const_traits
Chris@16:     : std::iterator_traits<Iterator>
Chris@16: {
Chris@16:     typedef typename std::iterator_traits<Iterator>::distance_type difference_type;
Chris@16:     typedef const typename std::iterator_traits<Iterator>::value_type* pointer;
Chris@16:     typedef const typename std::iterator_traits<Iterator>::value_type& reference;
Chris@16: };
Chris@16: 
Chris@16: #   ifdef BOOST_BAD_OUTPUT_ITERATOR_SPECIALIZATION
Chris@16: template <class Iterator>
Chris@16: struct is_bad_output_iterator
Chris@16:     : is_base_and_derived<
Chris@16:         std::iterator<std::output_iterator_tag,void,void,void,void>
Chris@16:         , Iterator>
Chris@16: {
Chris@16: };
Chris@16: 
Chris@16: struct bad_output_iterator_traits
Chris@16: {
Chris@16:     typedef void value_type;
Chris@16:     typedef void difference_type;
Chris@16:     typedef std::output_iterator_tag iterator_category;
Chris@16:     typedef void pointer;
Chris@16:     typedef void reference;
Chris@16: };
Chris@16: #   endif
Chris@16: 
Chris@16: // If we're looking at an MSVC6 (old Dinkumware) ``standard''
Chris@16: // iterator, this will generate an appropriate traits class. 
Chris@16: template <class Iterator>
Chris@16: struct msvc_stdlib_iterator_traits
Chris@16:     : mpl::if_<
Chris@16:        is_mutable_iterator<Iterator>
Chris@16:        , msvc_stdlib_mutable_traits<Iterator>
Chris@16:        , msvc_stdlib_const_traits<Iterator>
Chris@16:       >::type
Chris@16: {};
Chris@16: 
Chris@16: template <class Iterator>
Chris@16: struct non_pointer_iterator_traits
Chris@16:     : mpl::if_<
Chris@16:         // if the iterator contains all the right nested types...
Chris@16:         is_full_iterator_traits<Iterator>
Chris@16:         // Use a standard iterator_traits implementation
Chris@16:         , standard_iterator_traits<Iterator>
Chris@16: #   ifdef BOOST_BAD_CONTAINER_ITERATOR_CATEGORY_TYPEDEF
Chris@16:         // Check for STLPort 4.0 broken _Iterator_category type
Chris@16:         , mpl::if_<
Chris@16:              is_stlport_40_debug_iterator<Iterator>
Chris@16:              , stlport_40_debug_iterator_traits<Iterator>
Chris@16: #   endif
Chris@16:         // Otherwise, assume it's a Dinkum iterator
Chris@16:         , msvc_stdlib_iterator_traits<Iterator>
Chris@16: #   ifdef BOOST_BAD_CONTAINER_ITERATOR_CATEGORY_TYPEDEF
Chris@16:         >::type
Chris@16: #   endif 
Chris@16:     >::type
Chris@16: {
Chris@16: };
Chris@16: 
Chris@16: template <class Iterator>
Chris@16: struct iterator_traits_aux
Chris@16:     : mpl::if_<
Chris@16:         is_pointer<Iterator>
Chris@16:         , pointer_iterator_traits<Iterator>
Chris@16:         , non_pointer_iterator_traits<Iterator>
Chris@16:     >::type
Chris@16: {
Chris@16: };
Chris@16: 
Chris@16: template <class Iterator>
Chris@16: struct iterator_traits
Chris@16: {
Chris@16:     // Explicit forwarding from base class needed to keep MSVC6 happy
Chris@16:     // under some circumstances.
Chris@16:  private:
Chris@16: #   ifdef BOOST_BAD_OUTPUT_ITERATOR_SPECIALIZATION
Chris@16:     typedef 
Chris@16:     typename mpl::if_<
Chris@16:         is_bad_output_iterator<Iterator>
Chris@16:         , bad_output_iterator_traits
Chris@16:         , iterator_traits_aux<Iterator>
Chris@16:     >::type base;
Chris@16: #   else
Chris@16:     typedef iterator_traits_aux<Iterator> base;
Chris@16: #   endif
Chris@16:  public:
Chris@16:     typedef typename base::value_type value_type;
Chris@16:     typedef typename base::pointer pointer;
Chris@16:     typedef typename base::reference reference;
Chris@16:     typedef typename base::difference_type difference_type;
Chris@16:     typedef typename base::iterator_category iterator_category;
Chris@16: };
Chris@16: 
Chris@16: // This specialization cuts off ETI (Early Template Instantiation) for MSVC.
Chris@16: template <> struct iterator_traits<int>
Chris@16: {
Chris@16:     typedef int value_type;
Chris@16:     typedef int pointer;
Chris@16:     typedef int reference;
Chris@16:     typedef int difference_type;
Chris@16:     typedef int iterator_category;
Chris@16: };
Chris@16: 
Chris@16: }} // namespace boost::detail
Chris@16: 
Chris@16: #  endif // workarounds
Chris@16: 
Chris@16: namespace boost { namespace detail {
Chris@16: 
Chris@16: namespace iterator_traits_
Chris@16: {
Chris@16:   template <class Iterator, class Difference>
Chris@16:   struct distance_select
Chris@16:   {
Chris@16:       static Difference execute(Iterator i1, const Iterator i2, ...)
Chris@16:       {
Chris@16:           Difference result = 0;
Chris@16:           while (i1 != i2)
Chris@16:           {
Chris@16:               ++i1;
Chris@16:               ++result;
Chris@16:           }
Chris@16:           return result;
Chris@16:       }
Chris@16: 
Chris@16:       static Difference execute(Iterator i1, const Iterator i2, std::random_access_iterator_tag*)
Chris@16:       {
Chris@16:           return i2 - i1;
Chris@16:       }
Chris@16:   };
Chris@16: } // namespace boost::detail::iterator_traits_
Chris@16: 
Chris@16: template <class Iterator>
Chris@16: inline typename iterator_traits<Iterator>::difference_type
Chris@16: distance(Iterator first, Iterator last)
Chris@16: {
Chris@16:     typedef typename iterator_traits<Iterator>::difference_type diff_t;
Chris@16:     typedef typename ::boost::detail::iterator_traits<Iterator>::iterator_category iterator_category;
Chris@16:     
Chris@16:     return iterator_traits_::distance_select<Iterator,diff_t>::execute(
Chris@16:         first, last, (iterator_category*)0);
Chris@16: }
Chris@16: 
Chris@16: }}
Chris@16: 
Chris@16: # endif
Chris@16: 
Chris@16: 
Chris@16: # undef BOOST_BAD_CONTAINER_ITERATOR_CATEGORY_TYPEDEF
Chris@16: # undef BOOST_BAD_OUTPUT_ITERATOR_SPECIALIZATION
Chris@16: 
Chris@16: #endif // ITERATOR_DWA122600_HPP_