feedc0de/boost_iterator
1
0
Fork 0
forked from boostorg/iterator
Code Pull Requests Activity

Refactored minimum_category

Browse Source 
[SVN r20865]
This commit is contained in:
Dave Abrahams
2003-11-19 20:16:52 +00:00
parent eb73b8e0e2
commit 6e06e4f89e
3 changed files with 93 additions and 79 deletions
Download Patch File Download Diff File Expand all files Collapse all files

90
include/boost/iterator/detail/minimum_category.hpp Executable file
View File

@ -0,0 +1,90 @@
// Copyright David Abrahams 2003. Use, modification and distribution is
// subject to 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 MINIMUM_CATEGORY_DWA20031119_HPP
# define MINIMUM_CATEGORY_DWA20031119_HPP
# include <boost/type_traits/is_convertible.hpp>
# include <boost/type_traits/is_same.hpp>
# include <boost/mpl/aux_/lambda_support.hpp>
namespace boost { namespace detail {
//
// Returns the minimum category type or error_type
// if T1 and T2 are unrelated.
//
// For compilers not supporting is_convertible this only
// works with the new boost return and traversal category
// types. The exact boost _types_ are required. No derived types
// will work.
//
//
template <bool GreaterEqual, bool LessEqual>
struct minimum_category_impl;
template <class T1, class T2>
struct error_not_related_by_convertibility;
template <>
struct minimum_category_impl<true,false>
{
template <class T1, class T2> struct apply
{
typedef T2 type;
};
};
template <>
struct minimum_category_impl<false,true>
{
template <class T1, class T2> struct apply
{
typedef T1 type;
};
};
template <>
struct minimum_category_impl<true,true>
{
template <class T1, class T2> struct apply
{
BOOST_STATIC_ASSERT((is_same<T1,T2>::value));
typedef T1 type;
};
};
template <>
struct minimum_category_impl<false,false>
{
template <class T1, class T2> struct apply
: error_not_related_by_convertibility<T1,T2>
{
};
};
template <class T1, class T2>
struct minimum_category
{
typedef minimum_category_impl<
::boost::is_convertible<T1,T2>::value
, ::boost::is_convertible<T2,T1>::value
> outer;
typedef typename outer::template apply<T1,T2> inner;
typedef typename inner::type type;
BOOST_MPL_AUX_LAMBDA_SUPPORT(2,minimum_category,(T1,T2))
};
# if BOOST_WORKAROUND(BOOST_MSVC, == 1200)
template <>
struct minimum_category<int,int>
{
typedef int type;
};
# endif
}} // namespace boost::detail
#endif // MINIMUM_CATEGORY_DWA20031119_HPP

80
include/boost/iterator/iterator_categories.hpp
View File

@ -17,10 +17,8 @@
# include <boost/mpl/identity.hpp>
# include <boost/mpl/placeholders.hpp>
# include <boost/mpl/aux_/lambda_support.hpp>
# include <boost/mpl/aux_/msvc_eti_base.hpp>
# include <boost/type_traits/is_convertible.hpp>
# include <boost/type_traits/is_same.hpp>
# include <boost/static_assert.hpp>
@ -44,83 +42,7 @@ struct random_access_traversal_tag
: bidirectional_traversal_tag {};
namespace detail
{
//
// Returns the minimum category type or error_type
// if T1 and T2 are unrelated.
//
// For compilers not supporting is_convertible this only
// works with the new boost return and traversal category
// types. The exact boost _types_ are required. No derived types
// will work.
//
//
template <bool GreaterEqual, bool LessEqual>
struct minimum_category_impl;
template <class T1, class T2>
struct error_not_related_by_convertibility;
template <>
struct minimum_category_impl<true,false>
{
template <class T1, class T2> struct apply
{
typedef T2 type;
};
};
template <>
struct minimum_category_impl<false,true>
{
template <class T1, class T2> struct apply
{
typedef T1 type;
};
};
template <>
struct minimum_category_impl<true,true>
{
template <class T1, class T2> struct apply
{
BOOST_STATIC_ASSERT((is_same<T1,T2>::value));
typedef T1 type;
};
};
template <>
struct minimum_category_impl<false,false>
{
template <class T1, class T2> struct apply
: error_not_related_by_convertibility<T1,T2>
{
};
};
template <class T1, class T2>
struct minimum_category
{
typedef minimum_category_impl<
::boost::is_convertible<T1,T2>::value
, ::boost::is_convertible<T2,T1>::value
> outer;
typedef typename outer::template apply<T1,T2> inner;
typedef inner::type type;
BOOST_MPL_AUX_LAMBDA_SUPPORT(2,minimum_category,(T1,T2))
};
# if BOOST_WORKAROUND(BOOST_MSVC, == 1200)
template <>
struct minimum_category<int,int>
{
typedef int type;
};
# endif
{
//
// Convert a "strictly old-style" iterator category to a traversal
// tag. This is broken out into a separate metafunction to reduce

2
include/boost/iterator/zip_iterator.hpp
View File

@ -28,6 +28,8 @@
#include <boost/iterator/iterator_categories.hpp>
#include <boost/detail/iterator.hpp>
#include <boost/iterator/detail/minimum_category.hpp>
#include <boost/tuple/tuple.hpp>
#if BOOST_WORKAROUND(__GNUC__, == 2) || BOOST_WORKAROUND(__MWERKS__, <= 0x2407)