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Added thomas' interoperability idea

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[SVN r21762]
This commit is contained in:
Dave Abrahams
2004-01-15 17:08:04 +00:00
parent 8c3ed628dc
commit c08cc33394
3 changed files with 122 additions and 30 deletions
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76
include/boost/iterator/iterator_facade.hpp
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@ -13,6 +13,7 @@
#include <boost/iterator.hpp>
#include <boost/iterator/interoperable.hpp>
#include <boost/iterator/iterator_traits.hpp>
#include <boost/iterator/detail/facade_iterator_category.hpp>
#include <boost/iterator/detail/enable_if.hpp>
@ -27,6 +28,8 @@
#include <boost/mpl/apply_if.hpp>
#include <boost/mpl/or.hpp>
#include <boost/mpl/and.hpp>
#include <boost/mpl/always.hpp>
#include <boost/mpl/apply.hpp>
#include <boost/iterator/detail/config_def.hpp> // this goes last
@ -216,6 +219,23 @@ namespace boost
return *iter;
}
struct choose_difference_type
{
template <class I1, class I2>
struct apply
: mpl::apply_if<
is_convertible<I2,I1>
# if BOOST_WORKAROUND(BOOST_MSVC, == 1200)
, typename I1::difference_type
, typename I2::difference_type
# else
, iterator_difference<I1>
, iterator_difference<I2>
# endif
>
{};
};
} // namespace detail
@ -226,7 +246,8 @@ namespace boost
, class Derived2, class V2, class TC2, class R2, class D2 \
> \
prefix typename detail::enable_if_interoperable< \
Derived1, Derived2, result_type \
Derived1, Derived2 \
, typename mpl::apply2<result_type,Derived1,Derived2>::type \
>::type \
operator op( \
iterator_facade<Derived1, V1, TC1, R1, D1> const& lhs \
@ -257,7 +278,7 @@ namespace boost
template <class I, class V, class TC, class R, class D> friend class iterator_facade;
# define BOOST_ITERATOR_FACADE_RELATION(op) \
BOOST_ITERATOR_FACADE_INTEROP_HEAD(friend,op, bool);
BOOST_ITERATOR_FACADE_INTEROP_HEAD(friend,op, mpl::always<bool>);
BOOST_ITERATOR_FACADE_RELATION(==)
BOOST_ITERATOR_FACADE_RELATION(!=)
@ -269,7 +290,7 @@ namespace boost
# undef BOOST_ITERATOR_FACADE_RELATION
BOOST_ITERATOR_FACADE_INTEROP_HEAD(
friend, -, typename Derived1::difference_type)
friend, -, detail::choose_difference_type)
;
BOOST_ITERATOR_FACADE_PLUS_HEAD(
@ -307,11 +328,17 @@ namespace boost
}
template <class Facade1, class Facade2>
static bool equal(Facade1 const& f1, Facade2 const& f2)
static bool equal(Facade1 const& f1, Facade2 const& f2, mpl::true_)
{
return f1.equal(f2);
}
template <class Facade1, class Facade2>
static bool equal(Facade1 const& f1, Facade2 const& f2, mpl::false_)
{
return f2.equal(f1);
}
template <class Facade>
static void advance(Facade& f, typename Facade::difference_type n)
{
@ -319,10 +346,17 @@ namespace boost
}
template <class Facade1, class Facade2>
static typename Facade1::difference_type distance_to(
Facade1 const& f1, Facade2 const& f2)
static typename Facade1::difference_type minus(
Facade1 const& f1, Facade2 const& f2, mpl::true_)
{
return f1.distance_to(f2);
return -f1.distance_to(f2);
}
template <class Facade1, class Facade2>
static typename Facade2::difference_type minus(
Facade1 const& f1, Facade2 const& f2, mpl::false_)
{
return f2.distance_to(f1);
}
private:
@ -531,23 +565,24 @@ namespace boost
// ----------------
//
# define BOOST_ITERATOR_FACADE_INTEROP(op, result_type, condition, return_prefix, base_op) \
# define BOOST_ITERATOR_FACADE_INTEROP(op, result_type, return_prefix, base_op) \
BOOST_ITERATOR_FACADE_INTEROP_HEAD(inline, op, result_type) \
{ \
/* For those compilers that do not support enable_if */ \
BOOST_STATIC_ASSERT(( \
is_interoperable< Derived1, Derived2 >::value \
&& condition \
)); \
return_prefix iterator_core_access::base_op( \
static_cast<Derived2 const&>(rhs), static_cast<Derived1 const&>(lhs)); \
static_cast<Derived1 const&>(lhs) \
, static_cast<Derived2 const&>(rhs) \
, is_convertible<Derived2,Derived1>() \
); \
}
# define BOOST_ITERATOR_FACADE_RELATION(op, return_prefix, base_op) \
BOOST_ITERATOR_FACADE_INTEROP( \
op \
, bool \
, true \
, mpl::always<bool> \
, return_prefix \
, base_op \
)
@ -555,22 +590,19 @@ namespace boost
BOOST_ITERATOR_FACADE_RELATION(==, return, equal)
BOOST_ITERATOR_FACADE_RELATION(!=, return !, equal)
BOOST_ITERATOR_FACADE_RELATION(<, return 0 >, distance_to)
BOOST_ITERATOR_FACADE_RELATION(>, return 0 <, distance_to)
BOOST_ITERATOR_FACADE_RELATION(<=, return 0 >=, distance_to)
BOOST_ITERATOR_FACADE_RELATION(>=, return 0 <=, distance_to)
BOOST_ITERATOR_FACADE_RELATION(<, return 0 >, minus)
BOOST_ITERATOR_FACADE_RELATION(>, return 0 <, minus)
BOOST_ITERATOR_FACADE_RELATION(<=, return 0 >=, minus)
BOOST_ITERATOR_FACADE_RELATION(>=, return 0 <=, minus)
# undef BOOST_ITERATOR_FACADE_RELATION
// operator- requires an additional part in the static assertion
BOOST_ITERATOR_FACADE_INTEROP(
-
, typename Derived1::difference_type
, (is_same<
BOOST_DEDUCED_TYPENAME Derived1::difference_type
, BOOST_DEDUCED_TYPENAME Derived2::difference_type
>::value)
, detail::choose_difference_type
, return
, distance_to )
, minus
)
# undef BOOST_ITERATOR_FACADE_INTEROP
# undef BOOST_ITERATOR_FACADE_INTEROP_HEAD

1
test/Jamfile
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@ -42,6 +42,7 @@ test-suite iterator
[ run filter_iterator_test.cpp ]
[ run reverse_iterator_test.cpp ]
[ run counting_iterator_test.cpp ]
[ run interoperable.cpp ]
[ run permutation_iterator_test.cpp : : : # <stlport-iostream>on
]

59
test/interoperable.cpp Executable file
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@ -0,0 +1,59 @@
// Copyright David Abrahams 2004. 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)
#include <boost/iterator/iterator_adaptor.hpp>
#include <boost/pending/iterator_tests.hpp>
#include <cassert>
struct mutable_it : boost::iterator_adaptor<mutable_it,int*>
{
typedef boost::iterator_adaptor<mutable_it,int*> super_t;
mutable_it();
explicit mutable_it(int* p) : super_t(p) {}
bool equal(mutable_it const& rhs) const
{
return this->base() == rhs.base();
}
};
struct constant_it : boost::iterator_adaptor<constant_it,int const*>
{
typedef boost::iterator_adaptor<constant_it,int const*> super_t;
constant_it();
explicit constant_it(int* p) : super_t(p) {}
constant_it(mutable_it const& x) : super_t(x.base()) {}
bool equal(constant_it const& rhs) const
{
return this->base() == rhs.base();
}
};
int main()
{
int data[] = { 49, 77 };
mutable_it i(data);
constant_it j(data + 1);
assert(i < j);
assert(j > i);
assert(i <= j);
assert(j >= i);
assert(j - i == 1);
assert(i - j == -1);
constant_it k = i;
assert(!(i < k));
assert(!(k > i));
assert(i <= k);
assert(k >= i);
assert(k - i == 0);
assert(i - k == 0);
return 0;
}