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Use boost/iterator/iterator_categories to select traits by category type

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[SVN r20460]
This commit is contained in:
Raoul Gough
2003-10-23 11:04:56 +00:00
parent 06814a2251
commit d17ce4e588
1 changed files with 17 additions and 72 deletions
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89
include/boost/python/suite/indexing/iterator_traits.hpp
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@@ -27,6 +27,7 @@
#include <boost/call_traits.hpp>
#include <boost/type_traits.hpp>
#include <boost/iterator/iterator_traits.hpp>
#include <boost/iterator/iterator_categories.hpp>
namespace boost { namespace python { namespace indexing {
#if !BOOST_MSVC
@@ -58,10 +59,10 @@ namespace boost { namespace python { namespace indexing {
typedef ::boost::detail::iterator_traits<Iterator> std_traits;
public:
typedef Iterator iterator;
typedef typename std_traits::value_type value_type;
typedef typename std_traits::reference reference;
typedef typename std_traits::difference_type difference_type;
typedef Iterator iterator;
typedef BOOST_DEDUCED_TYPENAME std_traits::value_type value_type;
typedef BOOST_DEDUCED_TYPENAME std_traits::reference reference;
typedef BOOST_DEDUCED_TYPENAME std_traits::difference_type difference_type;
BOOST_STATIC_CONSTANT (bool, has_copyable_iter = false);
BOOST_STATIC_CONSTANT (bool, is_reorderable = false);
@@ -94,67 +95,10 @@ namespace boost { namespace python { namespace indexing {
};
namespace iterator_detail {
typedef char input_sizer[1];
typedef char forward_sizer[2];
typedef char bidirectional_sizer[3];
typedef char random_access_sizer[4];
#if BOOST_WORKAROUND(__EDG_VERSION__, <= 238)
// Fix tested on "MIPSpro Compilers: Version 7.3.1.3m", where the
// overload resolution variant causes an "ambiguous by inheritance"
// error without even instantiating traits_by_category
template<typename Category> struct is_random_access {
static bool const value = ::boost::is_convertible<
Category, std::random_access_iterator_tag>::value;
};
template<typename Category> struct is_bidirectional {
static bool const value = ::boost::is_convertible<
Category, std::bidirectional_iterator_tag>::value;
};
template<typename Category> struct is_forward {
static bool const value = ::boost::is_convertible<
Category, std::forward_iterator_tag>::value;
};
template<typename Category> struct is_input {
static bool const value = ::boost::is_convertible<
Category, std::input_iterator_tag>::value;
};
template<typename Category> struct sizer_struct {
BOOST_STATIC_CONSTANT (size_t, value =
(is_random_access<Category>::value
? sizeof (random_access_sizer)
: (is_bidirectional<Category>::value
? sizeof (bidirectional_sizer)
: (is_forward<Category>::value
? sizeof (forward_sizer)
: (is_input<Category>::value
? sizeof (input_sizer)
: 0)))));
};
#else
input_sizer &sizer_fn (std::input_iterator_tag const &);
forward_sizer &sizer_fn (std::forward_iterator_tag const &);
bidirectional_sizer &sizer_fn (std::bidirectional_iterator_tag const &);
random_access_sizer &sizer_fn (std::random_access_iterator_tag const &);
template<typename Category> struct sizer_struct {
BOOST_STATIC_CONSTANT (size_t, value =
sizeof (sizer_fn (Category())));
};
#endif
template<size_t Size> struct traits_by_size { };
template<typename TraversalTag> struct traits_by_category { };
template<>
struct traits_by_size<sizeof(input_sizer)> {
struct traits_by_category<std::input_iterator_tag> {
template<typename Iterator>
struct traits {
typedef input_iterator_traits<Iterator> type;
@@ -162,7 +106,7 @@ namespace boost { namespace python { namespace indexing {
};
template<>
struct traits_by_size<sizeof(forward_sizer)> {
struct traits_by_category<std::forward_iterator_tag> {
template<typename Iterator>
struct traits {
typedef forward_iterator_traits<Iterator> type;
@@ -170,7 +114,7 @@ namespace boost { namespace python { namespace indexing {
};
template<>
struct traits_by_size<sizeof(bidirectional_sizer)> {
struct traits_by_category<std::bidirectional_iterator_tag> {
template<typename Iterator>
struct traits {
typedef bidirectional_iterator_traits<Iterator> type;
@@ -178,7 +122,7 @@ namespace boost { namespace python { namespace indexing {
};
template<>
struct traits_by_size<sizeof(random_access_sizer)> {
struct traits_by_category<std::random_access_iterator_tag > {
template<typename Iterator>
struct traits {
typedef random_access_iterator_traits<Iterator> type;
@@ -186,21 +130,22 @@ namespace boost { namespace python { namespace indexing {
};
template<typename Iterator>
class traits_by_category {
typedef typename BOOST_ITERATOR_CATEGORY<Iterator>::type category;
class deduced_traits {
typedef BOOST_DEDUCED_TYPENAME BOOST_ITERATOR_CATEGORY<
Iterator>::type category;
BOOST_STATIC_CONSTANT (
size_t, size = sizer_struct<category>::value);
typedef BOOST_DEDUCED_TYPENAME ::boost::detail::std_category <
category>::type max_category;
public:
typedef typename traits_by_size<size>
typedef typename traits_by_category <max_category>
::template traits<Iterator>::type type;
};
}
template<typename Iterator>
struct iterator_traits
: public iterator_detail::traits_by_category<Iterator>::type
: public iterator_detail::deduced_traits<Iterator>::type
{
};
} } }