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