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Refactored pop_back_iterator into a reusable iterator_adaptor

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[SVN r73654]
This commit is contained in:
Joel de Guzman
2011-08-11 14:43:59 +00:00
parent 760c1a534c
commit e8b0f98a55
2 changed files with 142 additions and 70 deletions
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95
include/boost/fusion/algorithm/transformation/pop_back.hpp
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@ -10,7 +10,7 @@
#include <boost/fusion/view/iterator_range/iterator_range.hpp>
#include <boost/fusion/sequence/intrinsic/begin.hpp>
#include <boost/fusion/sequence/intrinsic/end.hpp>
#include <boost/fusion/iterator/iterator_facade.hpp>
#include <boost/fusion/iterator/iterator_adapter.hpp>
#include <boost/fusion/iterator/next.hpp>
#include <boost/mpl/minus.hpp>
#include <boost/mpl/int.hpp>
@ -19,94 +19,49 @@ namespace boost { namespace fusion
{
template <typename Iterator_>
struct pop_back_iterator
: iterator_facade<
: iterator_adapter<
pop_back_iterator<Iterator_>
, typename Iterator_::category>
, Iterator_>
{
typedef Iterator_ base_type;
base_type base;
typedef iterator_adapter<
pop_back_iterator<Iterator_>
, Iterator_>
base_type;
pop_back_iterator(base_type const& base)
: base(base) {}
pop_back_iterator(Iterator_ const& iterator_base)
: base_type(iterator_base) {}
template <typename BaseIterator>
struct make
{
typedef pop_back_iterator<BaseIterator> type;
static type
call(BaseIterator const& i)
{
return type(i);
}
};
template <typename I1, typename I2>
struct equal_to
: result_of::equal_to<
typename result_of::next<
typename I1::base_type>::type
, typename I2::base_type
typename I1::iterator_base_type>::type
, typename I2::iterator_base_type
>
{};
template <typename Iterator, typename N>
struct advance
: pop_back_iterator<
typename result_of::advance<
typename Iterator::base_type, N>::type
>
{
};
template <typename First, typename Last>
struct distance
: mpl::minus<
typename result_of::distance<
typename First::base_type
, typename Last::base_type
typename First::iterator_base_type
, typename Last::iterator_base_type
>::type
, mpl::int_<1>
>::type
{};
template <typename Iterator>
struct value_of
: result_of::value_of<typename Iterator::base_type> {};
template <typename Iterator>
struct deref
{
typedef typename
result_of::deref<typename Iterator::base_type>::type
type;
static type
call(Iterator const& it)
{
return fusion::deref(it.base);
}
};
template <typename Iterator>
struct next
{
typedef pop_back_iterator<
typename result_of::next<
typename Iterator::base_type
>::type>
type;
static type
call(Iterator const& i)
{
return fusion::next(i.base);
}
};
template <typename Iterator>
struct prior
{
typedef pop_back_iterator<
typename result_of::prior<
typename Iterator::base_type
>::type>
type;
static type
call(Iterator const& i)
{
return fusion::prior(i.base);
}
};
};
namespace result_of

117
include/boost/fusion/iterator/iterator_adapter.hpp Normal file
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@ -0,0 +1,117 @@
/*=============================================================================
Copyright (c) 2001-2011 Joel de Guzman
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)
==============================================================================*/
#if !defined(FUSION_ITERATOR_ADAPTER_08112011_0942)
#define FUSION_ITERATOR_ADAPTER_08112011_0942
#include <boost/fusion/iterator/detail/advance.hpp>
#include <boost/fusion/iterator/iterator_facade.hpp>
namespace boost { namespace fusion
{
template <typename Derived_, typename Iterator_>
struct iterator_adapter
: iterator_facade<
Derived_
, typename Iterator_::category>
{
typedef Iterator_ iterator_base_type;
iterator_base_type iterator_base;
iterator_adapter(iterator_base_type const& iterator_base)
: iterator_base(iterator_base) {}
// default implementation
template <typename I1, typename I2>
struct equal_to
: result_of::equal_to<
typename I1::iterator_base_type
, typename I2::iterator_base_type
>
{};
// default implementation
template <typename Iterator, typename N>
struct advance
: Derived_::template make<
typename result_of::advance<
typename Iterator::iterator_base_type, N
>::type
>
{
};
// default implementation
template <typename First, typename Last>
struct distance
: result_of::distance<
typename First::iterator_base_type
, typename Last::iterator_base_type
>
{};
// default implementation
template <typename Iterator>
struct value_of
: result_of::value_of<
typename Iterator::iterator_base_type
>
{};
// default implementation
template <typename Iterator>
struct deref
{
typedef typename
result_of::deref<
typename Iterator::iterator_base_type
>::type
type;
static type
call(Iterator const& it)
{
return fusion::deref(it.iterator_base);
}
};
// default implementation
template <typename Iterator>
struct next
{
typedef typename Derived_::template make<
typename result_of::next<
typename Iterator::iterator_base_type
>::type>::type
type;
static type
call(Iterator const& i)
{
return type(fusion::next(i.iterator_base));
}
};
// default implementation
template <typename Iterator>
struct prior
{
typedef typename Derived_::template make<
typename result_of::prior<
typename Iterator::iterator_base_type
>::type>::type
type;
static type
call(Iterator const& i)
{
return type(fusion::prior(i.iterator_base));
}
};
};
}}
#endif