Initial checkin

[SVN r8664]
This commit is contained in:
Dave Abrahams
2001-01-21 05:18:41 +00:00
parent 4d24f82e6e
commit 5963c3d44d

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// (C) Copyright David Abrahams 2001. Permission to copy, use, modify,
// sell and distribute this software is granted provided this
// copyright notice appears in all copies. This software is provided
// "as is" without express or implied warranty, and with no claim as
// to its suitability for any purpose.
// Boost versions of
//
// std::iterator_traits<>::iterator_category
// std::iterator_traits<>::difference_type
// std::distance()
//
// ...for all compilers and iterators
#ifndef ITERATOR_DWA122600_HPP_
# define ITERATOR_DWA122600_HPP_
# include <boost/config.hpp>
# include <boost/type_traits.hpp>
# include <iterator>
# include <cstddef>
// 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.
// the proper typedef.
# if defined(__SGI_STL_PORT) && (__SGI_STL_PORT <= 0x410) && !defined(__STL_CLASS_PARTIAL_SPECIALIZATION)
# ifdef __STL_DEBUG
# define BOOST_BAD_CONTAINER_ITERATOR_CATEGORY_TYPEDEF
# endif
# define BOOST_BAD_OUTPUT_ITERATOR_SPECIALIZATION
# endif // STLPort <= 4.1b4 && no partial specialization
# ifdef BOOST_BAD_CONTAINER_ITERATOR_CATEGORY_TYPEDEF
# include <vector>
# include <list>
# include <set>
# include <map>
# include <deque>
# include <slist>
# include <hash_map>
# include <hash_set>
# include <string>
# endif
namespace boost { namespace detail {
# if !defined(BOOST_NO_STD_ITERATOR_TRAITS) && !defined(BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION)
using std::iterator_traits;
using std::distance;
# else
// Workarounds for less-capable implementations
template <bool is_ptr> struct iterator_traits_select;
template <> struct iterator_traits_select<true>
{
template <class Ptr>
struct traits
{
typedef std::ptrdiff_t difference_type;
typedef std::random_access_iterator_tag iterator_category;
};
};
# ifdef BOOST_BAD_CONTAINER_ITERATOR_CATEGORY_TYPEDEF
no_result bad_category_helper(...);
template <class C, class T> yes_result bad_category_helper(std::_DBG_iter<C,T>*);
template <bool has_bad_category_typedef> struct bad_category_select;
template <>
struct bad_category_select<true>
{
template <class Iterator>
struct category { typedef typename Iterator::_Iterator_category type; };
};
template <>
struct bad_category_select<false>
{
template <class Iterator>
struct category { typedef typename Iterator::iterator_category type; };
};
template <class Iterator>
struct iterator_category_select
{
private:
static Iterator p;
enum { has_bad_category
= sizeof(bad_category_helper(&p)) == sizeof(yes_result) };
typedef bad_category_select<has_bad_category> category_select;
public:
typedef typename category_select::template category<Iterator>::type type;
};
# endif
# ifdef BOOST_BAD_OUTPUT_ITERATOR_SPECIALIZATION
template <bool is_bad_output_iterator> struct bad_difference_select;
template <>
struct bad_difference_select<true>
{
template <class Iterator>
struct difference { typedef void type; };
};
template <>
struct bad_difference_select<false>
{
template <class Iterator>
struct difference { typedef typename Iterator::difference_type type; };
};
yes_result bad_output_iterator_helper(std::iterator<std::output_iterator_tag,void,void,void,void>*);
no_result bad_output_iterator_helper(...);
# endif
template <> struct iterator_traits_select<false>
{
template <class Iterator>
struct traits
# if defined(BOOST_NO_STD_ITERATOR_TRAITS)
{
# if defined(BOOST_MSVC) && !defined(__SGI_STL_PORT)
typedef typename Iterator::distance_type difference_type;
# elif !defined(BOOST_BAD_OUTPUT_ITERATOR_SPECIALIZATION)
typedef typename Iterator::difference_type difference_type;
# else
private:
// static Iterator *p;
typedef bad_difference_select<
is_convertible<const volatile Iterator*,
const volatile std::iterator<std::output_iterator_tag,void,void,void,void>*
>::value> difference_type_select;
public:
typedef typename difference_type_select::template difference<Iterator>::type difference_type;
# endif
# if !defined(BOOST_BAD_CONTAINER_ITERATOR_CATEGORY_TYPEDEF)
typedef typename Iterator::iterator_category iterator_category;
# else
typedef typename iterator_category_select<Iterator>::type iterator_category;
# endif
};
# else
{
typedef typename std::iterator_traits<Iterator>::difference_type difference_type;
typedef typename std::iterator_traits<Iterator>::iterator_category iterator_category;
};
# endif
};
template <class Iterator>
struct iterator_traits
{
private:
typedef iterator_traits_select<is_pointer<remove_cv<Iterator>::type>::value> select;
typedef typename select::template traits<Iterator> traits;
public:
typedef typename traits::difference_type difference_type;
typedef typename traits::iterator_category iterator_category;
};
template <class Category>
struct distance_select {
template <class Iterator>
static typename ::boost::detail::iterator_traits<Iterator>::difference_type
distance(Iterator i1, const Iterator i2)
{
typename ::boost::detail::iterator_traits<Iterator>::difference_type result = 0;
while (i1 != i2)
{
++i1;
++result;
}
return result;
}
};
template <>
struct distance_select<std::random_access_iterator_tag> {
template <class Iterator>
static typename ::boost::detail::iterator_traits<Iterator>::difference_type
distance(const Iterator i1, const Iterator i2)
{
return i2 - i1;
}
};
template <class Iterator>
inline typename ::boost::detail::iterator_traits<Iterator>::difference_type
distance(const Iterator& first, const Iterator& last)
{
typedef typename ::boost::detail::iterator_traits<Iterator>::iterator_category iterator_category;
return distance_select<iterator_category>::distance(first, last);
}
# endif // workarounds
}}
# undef BOOST_BAD_CONTAINER_ITERATOR_CATEGORY_TYPEDEF
# undef BOOST_BAD_OUTPUT_ITERATOR_SPECIALIZATION
#endif // ITERATOR_DWA122600_HPP_