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rAKA akantu
aka_iterators.hh
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/**
* @file aka_iterators.hh
*
* @author Nicolas Richart <nicolas.richart@epfl.ch>
*
* @date creation: Fri Aug 11 2017
* @date last modification: Mon Jan 29 2018
*
* @brief iterator interfaces
*
* @section LICENSE
*
* Copyright (©) 2016-2018 EPFL (Ecole Polytechnique Fédérale de Lausanne)
* Laboratory (LSMS - Laboratoire de Simulation en Mécanique des Solides)
*
* Akantu is free software: you can redistribute it and/or modify it under the
* terms of the GNU Lesser General Public License as published by the Free
* Software Foundation, either version 3 of the License, or (at your option) any
* later version.
*
* Akantu is distributed in the hope that it will be useful, but WITHOUT ANY
* WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
* A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more
* details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with Akantu. If not, see <http://www.gnu.org/licenses/>.
*
*/
/* -------------------------------------------------------------------------- */
#include "aka_compatibilty_with_cpp_standard.hh"
#include "aka_tuple_tools.hh"
/* -------------------------------------------------------------------------- */
#include <iterator>
#include <tuple>
#include <utility>
/* -------------------------------------------------------------------------- */
#ifndef AKANTU_AKA_ITERATORS_HH
#define AKANTU_AKA_ITERATORS_HH
#ifndef AKANTU_ITERATOR_NAMESPACE
#define AKANTU_ITERATOR_NAMESPACE akantu
#endif
namespace
AKANTU_ITERATOR_NAMESPACE
{
/* -------------------------------------------------------------------------- */
namespace
iterators
{
namespace
details
{
template
<
typename
cat1
,
typename
cat2
>
using
is_iterator_category_at_least
=
std
::
is_same
<
std
::
common_type_t
<
cat1
,
cat2
>
,
cat2
>
;
}
template
<
class
...
Iterators
>
class
ZipIterator
{
private
:
using
tuple_t
=
std
::
tuple
<
Iterators
...
>
;
public
:
using
value_type
=
std
::
tuple
<
typename
std
::
iterator_traits
<
Iterators
>::
value_type
...
>
;
using
difference_type
=
std
::
common_type_t
<
typename
std
::
iterator_traits
<
Iterators
>::
difference_type
...
>
;
using
pointer
=
std
::
tuple
<
typename
std
::
iterator_traits
<
Iterators
>::
pointer
...
>
;
using
reference
=
std
::
tuple
<
typename
std
::
iterator_traits
<
Iterators
>::
reference
...
>
;
using
iterator_category
=
// std::input_iterator_tag;
std
::
common_type_t
<
typename
std
::
iterator_traits
<
Iterators
>::
iterator_category
...
>
;
using
nb_iterators
=
std
::
tuple_size
<
tuple_t
>
;
public
:
explicit
ZipIterator
(
tuple_t
iterators
)
:
iterators
(
std
::
move
(
iterators
))
{}
ZipIterator
(
const
ZipIterator
&
other
)
=
default
;
ZipIterator
(
ZipIterator
&&
other
)
noexcept
=
default
;
ZipIterator
&
operator
=
(
const
ZipIterator
&
other
)
=
default
;
ZipIterator
&
operator
=
(
ZipIterator
&&
other
)
noexcept
=
default
;
/* ---------------------------------------------------------------------- */
template
<
class
iterator_category_
=
iterator_category
,
std
::
enable_if_t
<
details
::
is_iterator_category_at_least
<
iterator_category_
,
std
::
bidirectional_iterator_tag
>::
value
>
*
=
nullptr
>
ZipIterator
&
operator
--
()
{
tuple
::
foreach
([](
auto
&&
it
)
{
--
it
;
},
iterators
);
return
*
this
;
}
template
<
class
iterator_category_
=
iterator_category
,
std
::
enable_if_t
<
details
::
is_iterator_category_at_least
<
iterator_category_
,
std
::
bidirectional_iterator_tag
>::
value
>
*
=
nullptr
>
ZipIterator
operator
--
(
int
a
)
{
auto
cpy
=
*
this
;
this
->
operator
--
();
return
cpy
;
}
// input iterator ++it
ZipIterator
&
operator
++
()
{
tuple
::
foreach
([](
auto
&&
it
)
{
++
it
;
},
iterators
);
return
*
this
;
}
// input iterator it++
ZipIterator
operator
++
(
int
)
{
auto
cpy
=
*
this
;
this
->
operator
++
();
return
cpy
;
}
// input iterator it != other_it
bool
operator
!=
(
const
ZipIterator
&
other
)
const
{
// return tuple::are_not_equal(iterators, other.iterators);
return
std
::
get
<
0
>
(
iterators
)
!=
std
::
get
<
0
>
(
other
.
iterators
);
// helps the compiler to optimize
}
// input iterator dereference *it
decltype
(
auto
)
operator
*
()
{
return
tuple
::
transform
([](
auto
&&
it
)
->
decltype
(
auto
)
{
return
*
it
;
},
iterators
);
}
template
<
class
iterator_category_
=
iterator_category
,
std
::
enable_if_t
<
details
::
is_iterator_category_at_least
<
iterator_category_
,
std
::
random_access_iterator_tag
>::
value
>
*
=
nullptr
>
difference_type
operator
-
(
const
ZipIterator
&
other
)
{
return
std
::
get
<
0
>
(
this
->
iterators
)
-
std
::
get
<
0
>
(
other
.
iterators
);
}
// random iterator it[idx]
template
<
class
iterator_category_
=
iterator_category
,
std
::
enable_if_t
<
details
::
is_iterator_category_at_least
<
iterator_category_
,
std
::
random_access_iterator_tag
>::
value
>
*
=
nullptr
>
decltype
(
auto
)
operator
[](
std
::
size_t
idx
)
{
return
tuple
::
transform
(
[
idx
](
auto
&&
it
)
->
decltype
(
auto
)
{
return
it
[
idx
];
},
iterators
);
}
// random iterator it + n
template
<
class
iterator_category_
=
iterator_category
,
std
::
enable_if_t
<
details
::
is_iterator_category_at_least
<
iterator_category_
,
std
::
random_access_iterator_tag
>::
value
>
*
=
nullptr
>
decltype
(
auto
)
operator
+
(
std
::
size_t
n
)
{
return
ZipIterator
(
std
::
forward
<
tuple_t
>
(
tuple
::
transform
(
[
n
](
auto
&&
it
)
->
decltype
(
auto
)
{
return
it
+
n
;
},
iterators
)));
}
// random iterator it - n
template
<
class
iterator_category_
=
iterator_category
,
std
::
enable_if_t
<
details
::
is_iterator_category_at_least
<
iterator_category_
,
std
::
random_access_iterator_tag
>::
value
>
*
=
nullptr
>
decltype
(
auto
)
operator
-
(
std
::
size_t
n
)
{
return
ZipIterator
(
std
::
forward
<
tuple_t
>
(
tuple
::
transform
(
[
n
](
auto
&&
it
)
->
decltype
(
auto
)
{
return
it
-
n
;
},
iterators
)));
}
template
<
class
iterator_category_
=
iterator_category
,
std
::
enable_if_t
<
details
::
is_iterator_category_at_least
<
iterator_category_
,
std
::
forward_iterator_tag
>::
value
>
*
=
nullptr
>
bool
operator
==
(
const
ZipIterator
&
other
)
const
{
return
not
tuple
::
are_not_equal
(
iterators
,
other
.
iterators
);
}
private
:
tuple_t
iterators
;
};
}
// namespace iterators
/* -------------------------------------------------------------------------- */
template
<
class
...
Iterators
>
decltype
(
auto
)
zip_iterator
(
std
::
tuple
<
Iterators
...
>
&&
iterators_tuple
)
{
auto
zip
=
iterators
::
ZipIterator
<
Iterators
...
>
(
std
::
forward
<
decltype
(
iterators_tuple
)
>
(
iterators_tuple
));
return
zip
;
}
/* -------------------------------------------------------------------------- */
namespace
containers
{
template
<
class
...
Containers
>
class
ZipContainer
{
using
containers_t
=
std
::
tuple
<
Containers
...
>
;
public
:
explicit
ZipContainer
(
Containers
&&
...
containers
)
:
containers
(
std
::
forward
<
Containers
>
(
containers
)...)
{}
decltype
(
auto
)
begin
()
const
{
return
zip_iterator
(
tuple
::
transform
([](
auto
&&
c
)
{
return
c
.
begin
();
},
std
::
forward
<
containers_t
>
(
containers
)));
}
decltype
(
auto
)
end
()
const
{
return
zip_iterator
(
tuple
::
transform
([](
auto
&&
c
)
{
return
c
.
end
();
},
std
::
forward
<
containers_t
>
(
containers
)));
}
decltype
(
auto
)
begin
()
{
return
zip_iterator
(
tuple
::
transform
([](
auto
&&
c
)
{
return
c
.
begin
();
},
std
::
forward
<
containers_t
>
(
containers
)));
}
decltype
(
auto
)
end
()
{
return
zip_iterator
(
tuple
::
transform
([](
auto
&&
c
)
{
return
c
.
end
();
},
std
::
forward
<
containers_t
>
(
containers
)));
}
// template <class Container = std::tuple_element<0, containers_t>,
// std::enable_if_t<std::is_integral<decltype(
// std::declval<Container>().size())>::value> * = nullptr>
// decltype(auto) size() {
// return std::forward<Container>(std::get<0>(containers)).size();
// }
private
:
containers_t
containers
;
};
template
<
class
Iterator
>
class
Range
{
public
:
using
iterator
=
Iterator
;
// ugly trick
using
const_iterator
=
Iterator
;
explicit
Range
(
Iterator
&&
it1
,
Iterator
&&
it2
)
:
iterators
(
std
::
forward
<
Iterator
>
(
it1
),
std
::
forward
<
Iterator
>
(
it2
))
{}
decltype
(
auto
)
begin
()
const
{
return
std
::
get
<
0
>
(
iterators
);
}
decltype
(
auto
)
begin
()
{
return
std
::
get
<
0
>
(
iterators
);
}
decltype
(
auto
)
end
()
const
{
return
std
::
get
<
1
>
(
iterators
);
}
decltype
(
auto
)
end
()
{
return
std
::
get
<
1
>
(
iterators
);
}
private
:
std
::
tuple
<
Iterator
,
Iterator
>
iterators
;
};
}
// namespace containers
/* -------------------------------------------------------------------------- */
template
<
class
...
Containers
>
decltype
(
auto
)
zip
(
Containers
&&
...
conts
)
{
return
containers
::
ZipContainer
<
Containers
...
>
(
std
::
forward
<
Containers
>
(
conts
)...);
}
template
<
class
Iterator
>
decltype
(
auto
)
range
(
Iterator
&&
it1
,
Iterator
&&
it2
)
{
return
containers
::
Range
<
Iterator
>
(
std
::
forward
<
Iterator
>
(
it1
),
std
::
forward
<
Iterator
>
(
it2
));
}
/* -------------------------------------------------------------------------- */
/* Arange */
/* -------------------------------------------------------------------------- */
namespace
iterators
{
template
<
class
T
>
class
ArangeIterator
{
public
:
using
value_type
=
T
;
using
pointer
=
T
*
;
using
reference
=
T
&
;
using
difference_type
=
size_t
;
using
iterator_category
=
std
::
forward_iterator_tag
;
constexpr
ArangeIterator
(
T
value
,
T
step
)
:
value
(
value
),
step
(
step
)
{}
constexpr
ArangeIterator
(
const
ArangeIterator
&
)
=
default
;
constexpr
ArangeIterator
&
operator
++
()
{
value
+=
step
;
return
*
this
;
}
constexpr
T
operator
*
()
const
{
return
value
;
}
constexpr
bool
operator
==
(
const
ArangeIterator
&
other
)
const
{
return
(
value
==
other
.
value
)
and
(
step
==
other
.
step
);
}
constexpr
bool
operator
!=
(
const
ArangeIterator
&
other
)
const
{
return
not
operator
==
(
other
);
}
private
:
T
value
{
0
};
const
T
step
{
1
};
};
}
// namespace iterators
namespace
containers
{
template
<
class
T
>
class
ArangeContainer
{
public
:
using
iterator
=
iterators
::
ArangeIterator
<
T
>
;
using
const_iterator
=
iterators
::
ArangeIterator
<
T
>
;
constexpr
ArangeContainer
(
T
start
,
T
stop
,
T
step
=
1
)
:
start
(
start
),
stop
((
stop
-
start
)
%
step
==
0
?
stop
:
start
+
(
1
+
(
stop
-
start
)
/
step
)
*
step
),
step
(
step
)
{}
explicit
constexpr
ArangeContainer
(
T
stop
)
:
ArangeContainer
(
0
,
stop
,
1
)
{}
constexpr
T
operator
[](
size_t
i
)
{
T
val
=
start
+
i
*
step
;
assert
(
val
<
stop
&&
"i is out of range"
);
return
val
;
}
constexpr
T
size
()
{
return
(
stop
-
start
)
/
step
;
}
constexpr
iterator
begin
()
{
return
iterator
(
start
,
step
);
}
constexpr
iterator
end
()
{
return
iterator
(
stop
,
step
);
}
private
:
const
T
start
{
0
},
stop
{
0
},
step
{
1
};
};
}
// namespace containers
template
<
class
T
,
typename
=
std
::
enable_if_t
<
std
::
is_integral
<
std
::
decay_t
<
T
>>::
value
>>
inline
decltype
(
auto
)
arange
(
const
T
&
stop
)
{
return
containers
::
ArangeContainer
<
T
>
(
stop
);
}
template
<
class
T1
,
class
T2
,
typename
=
std
::
enable_if_t
<
std
::
is_integral
<
std
::
common_type_t
<
T1
,
T2
>>::
value
>>
inline
constexpr
decltype
(
auto
)
arange
(
const
T1
&
start
,
const
T2
&
stop
)
{
return
containers
::
ArangeContainer
<
std
::
common_type_t
<
T1
,
T2
>>
(
start
,
stop
);
}
template
<
class
T1
,
class
T2
,
class
T3
,
typename
=
std
::
enable_if_t
<
std
::
is_integral
<
std
::
common_type_t
<
T1
,
T2
,
T3
>>::
value
>>
inline
constexpr
decltype
(
auto
)
arange
(
const
T1
&
start
,
const
T2
&
stop
,
const
T3
&
step
)
{
return
containers
::
ArangeContainer
<
std
::
common_type_t
<
T1
,
T2
,
T3
>>
(
start
,
stop
,
step
);
}
/* -------------------------------------------------------------------------- */
namespace
iterators
{
template
<
class
Iterator
>
class
EnumerateIterator
{
public
:
using
value_type
=
std
::
tuple
<
size_t
,
typename
std
::
iterator_traits
<
Iterator
>::
value_type
>
;
using
difference_type
=
size_t
;
using
pointer
=
std
::
tuple
<
size_t
,
typename
std
::
iterator_traits
<
Iterator
>::
pointer
>
;
using
reference
=
std
::
tuple
<
size_t
,
typename
std
::
iterator_traits
<
Iterator
>::
reference
>
;
using
iterator_category
=
std
::
input_iterator_tag
;
public
:
explicit
EnumerateIterator
(
Iterator
&&
iterator
)
:
iterator
(
iterator
)
{}
// input iterator ++it
EnumerateIterator
&
operator
++
()
{
++
iterator
;
++
index
;
return
*
this
;
}
// input iterator it++
EnumerateIterator
operator
++
(
int
)
{
auto
cpy
=
*
this
;
this
->
operator
++
();
return
cpy
;
}
// input iterator it != other_it
bool
operator
!=
(
const
EnumerateIterator
&
other
)
const
{
return
iterator
!=
other
.
iterator
;
}
// input iterator dereference *it
decltype
(
auto
)
operator
*
()
{
return
std
::
tuple_cat
(
std
::
make_tuple
(
index
),
*
iterator
);
}
bool
operator
==
(
const
EnumerateIterator
&
other
)
const
{
return
not
this
->
operator
!=
(
other
);
}
private
:
Iterator
iterator
;
size_t
index
{
0
};
};
template
<
class
Iterator
>
inline
constexpr
decltype
(
auto
)
enumerate
(
Iterator
&&
iterator
)
{
return
EnumerateIterator
<
Iterator
>
(
std
::
forward
<
Iterator
>
(
iterator
));
}
}
// namespace iterators
namespace
containers
{
template
<
class
...
Containers
>
class
EnumerateContainer
{
public
:
explicit
EnumerateContainer
(
Containers
&&
...
containers
)
:
zip_container
(
std
::
forward
<
Containers
>
(
containers
)...)
{}
decltype
(
auto
)
begin
()
{
return
iterators
::
enumerate
(
zip_container
.
begin
());
}
decltype
(
auto
)
begin
()
const
{
return
iterators
::
enumerate
(
zip_container
.
begin
());
}
decltype
(
auto
)
end
()
{
return
iterators
::
enumerate
(
zip_container
.
end
());
}
decltype
(
auto
)
end
()
const
{
return
iterators
::
enumerate
(
zip_container
.
end
());
}
private
:
ZipContainer
<
Containers
...
>
zip_container
;
};
}
// namespace containers
template
<
class
...
Container
>
inline
constexpr
decltype
(
auto
)
enumerate
(
Container
&&
...
container
)
{
return
containers
::
EnumerateContainer
<
Container
...
>
(
std
::
forward
<
Container
>
(
container
)...);
}
/* -------------------------------------------------------------------------- */
/* -------------------------------------------------------------------------- */
namespace
iterators
{
template
<
class
iterator_t
,
class
operator_t
>
class
transform_adaptor_iterator
{
public
:
using
value_type
=
decltype
(
std
::
declval
<
operator_t
>
()(
std
::
declval
<
typename
iterator_t
::
value_type
>
()));
using
difference_type
=
typename
iterator_t
::
difference_type
;
using
pointer
=
std
::
decay_t
<
value_type
>
*
;
using
reference
=
value_type
&
;
using
iterator_category
=
typename
iterator_t
::
iterator_category
;
transform_adaptor_iterator
(
iterator_t
it
,
operator_t
op
)
:
it
(
std
::
move
(
it
)),
op
(
op
)
{}
transform_adaptor_iterator
(
const
transform_adaptor_iterator
&
)
=
default
;
transform_adaptor_iterator
&
operator
++
()
{
++
it
;
return
*
this
;
}
decltype
(
auto
)
operator
*
()
{
return
op
(
std
::
forward
<
decltype
(
*
it
)
>
(
*
it
));
}
bool
operator
==
(
const
transform_adaptor_iterator
&
other
)
const
{
return
(
it
==
other
.
it
);
}
bool
operator
!=
(
const
transform_adaptor_iterator
&
other
)
const
{
return
not
operator
==
(
other
);
}
template
<
class
iterator_category_
=
iterator_category
,
std
::
enable_if_t
<
details
::
is_iterator_category_at_least
<
iterator_category_
,
std
::
random_access_iterator_tag
>::
value
>
*
=
nullptr
>
difference_type
operator
-
(
const
transform_adaptor_iterator
&
other
)
{
return
other
-
*
this
;
}
private
:
iterator_t
it
;
operator_t
op
;
};
template
<
class
iterator_t
,
class
operator_t
>
decltype
(
auto
)
make_transform_adaptor_iterator
(
iterator_t
it
,
operator_t
op
)
{
return
transform_adaptor_iterator
<
iterator_t
,
operator_t
>
(
it
,
std
::
forward
<
operator_t
>
(
op
));
}
}
// namespace iterators
namespace
containers
{
template
<
class
container_t
,
class
operator_t
>
class
TransformIteratorAdaptor
{
public
:
// using const_iterator = typename
// std::decay_t<container_t>::const_iterator; using iterator = typename
// std::decay_t<container_t>::iterator;
TransformIteratorAdaptor
(
container_t
&&
cont
,
operator_t
op
)
:
cont
(
std
::
forward
<
container_t
>
(
cont
)),
op
(
std
::
forward
<
operator_t
>
(
op
))
{}
decltype
(
auto
)
begin
()
const
{
return
iterators
::
make_transform_adaptor_iterator
(
cont
.
begin
(),
op
);
}
decltype
(
auto
)
begin
()
{
return
iterators
::
make_transform_adaptor_iterator
(
cont
.
begin
(),
op
);
}
decltype
(
auto
)
end
()
const
{
return
iterators
::
make_transform_adaptor_iterator
(
cont
.
end
(),
op
);
}
decltype
(
auto
)
end
()
{
return
iterators
::
make_transform_adaptor_iterator
(
cont
.
end
(),
op
);
}
private
:
container_t
cont
;
operator_t
op
;
};
}
// namespace containers
template
<
class
container_t
,
class
operator_t
>
decltype
(
auto
)
make_transform_adaptor
(
container_t
&&
cont
,
operator_t
&&
op
)
{
return
containers
::
TransformIteratorAdaptor
<
container_t
,
operator_t
>
(
std
::
forward
<
container_t
>
(
cont
),
std
::
forward
<
operator_t
>
(
op
));
}
template
<
class
container_t
>
decltype
(
auto
)
make_keys_adaptor
(
container_t
&&
cont
)
{
return
make_transform_adaptor
(
std
::
forward
<
container_t
>
(
cont
),
[](
auto
&&
pair
)
->
const
auto
&
{
return
pair
.
first
;
});
}
template
<
class
container_t
>
decltype
(
auto
)
make_values_adaptor
(
container_t
&&
cont
)
{
return
make_transform_adaptor
(
std
::
forward
<
container_t
>
(
cont
),
[](
auto
&&
pair
)
->
auto
&
{
return
pair
.
second
;
});
}
template
<
class
container_t
>
decltype
(
auto
)
make_dereference_adaptor
(
container_t
&&
cont
)
{
return
make_transform_adaptor
(
std
::
forward
<
container_t
>
(
cont
),
[](
auto
&&
value
)
->
decltype
(
*
value
)
{
return
*
value
;
});
}
template
<
class
...
zip_container_t
>
decltype
(
auto
)
make_zip_cat
(
zip_container_t
&&
...
cont
)
{
return
make_transform_adaptor
(
zip
(
std
::
forward
<
zip_container_t
>
(
cont
)...),
[](
auto
&&
value
)
{
return
tuple
::
flatten
(
value
);
});
}
/* -------------------------------------------------------------------------- */
namespace
iterators
{
template
<
class
filter_iterator_t
,
class
container_iterator_t
>
class
FilterIterator
{
public
:
using
value_type
=
decltype
(
std
::
declval
<
container_iterator_t
>
().
operator
[](
0
));
using
difference_type
=
typename
filter_iterator_t
::
difference_type
;
using
pointer
=
std
::
decay_t
<
value_type
>
*
;
using
reference
=
value_type
&
;
using
iterator_category
=
typename
filter_iterator_t
::
iterator_category
;
FilterIterator
(
filter_iterator_t
filter_it
,
container_iterator_t
container_begin
)
:
filter_it
(
std
::
move
(
filter_it
)),
container_begin
(
std
::
move
(
container_begin
))
{}
FilterIterator
(
const
FilterIterator
&
)
=
default
;
FilterIterator
&
operator
++
()
{
++
filter_it
;
return
*
this
;
}
decltype
(
auto
)
operator
*
()
{
auto
container_it
=
this
->
container_begin
+
*
this
->
filter_it
;
return
*
container_it
;
}
decltype
(
auto
)
operator
*
()
const
{
auto
container_it
=
this
->
container_begin
+
*
this
->
filter_it
;
return
*
container_it
;
}
bool
operator
==
(
const
FilterIterator
&
other
)
const
{
return
(
filter_it
==
other
.
filter_it
)
and
(
container_begin
==
other
.
container_begin
);
}
bool
operator
!=
(
const
FilterIterator
&
other
)
const
{
return
filter_it
!=
other
.
filter_it
;
}
private
:
filter_iterator_t
filter_it
;
container_iterator_t
container_begin
;
};
template
<
class
filter_iterator_t
,
class
container_iterator_t
>
decltype
(
auto
)
make_filter_iterator
(
filter_iterator_t
&&
filter_it
,
container_iterator_t
&&
container_begin
)
{
return
FilterIterator
<
filter_iterator_t
,
container_iterator_t
>
(
std
::
forward
<
filter_iterator_t
>
(
filter_it
),
std
::
forward
<
container_iterator_t
>
(
container_begin
));
}
}
// namespace iterators
namespace
containers
{
template
<
class
filter_t
,
class
Container
>
class
FilterAdaptor
{
public
:
FilterAdaptor
(
filter_t
&&
filter
,
Container
&&
container
)
:
filter
(
std
::
forward
<
filter_t
>
(
filter
)),
container
(
std
::
forward
<
Container
>
(
container
))
{
static_assert
(
std
::
is_same
<
typename
decltype
(
container
.
begin
())
::
iterator_category
,
std
::
random_access_iterator_tag
>::
value
,
"Containers must all have random iterators"
);
}
decltype
(
auto
)
begin
()
const
{
return
iterators
::
make_filter_iterator
(
filter
.
begin
(),
container
.
begin
());
}
decltype
(
auto
)
begin
()
{
return
iterators
::
make_filter_iterator
(
filter
.
begin
(),
container
.
begin
());
}
decltype
(
auto
)
end
()
const
{
return
iterators
::
make_filter_iterator
(
filter
.
end
(),
container
.
begin
());
}
decltype
(
auto
)
end
()
{
return
iterators
::
make_filter_iterator
(
filter
.
end
(),
container
.
begin
());
}
private
:
filter_t
filter
;
Container
container
;
};
}
// namespace containers
template
<
class
filter_t
,
class
Container
>
decltype
(
auto
)
filter
(
filter_t
&&
filter
,
Container
&&
container
)
{
return
containers
::
FilterAdaptor
<
filter_t
,
Container
>
(
std
::
forward
<
filter_t
>
(
filter
),
std
::
forward
<
Container
>
(
container
));
}
}
// namespace AKANTU_ITERATOR_NAMESPACE
namespace
std
{
template
<
typename
...
Its
>
struct
iterator_traits
<::
akantu
::
iterators
::
ZipIterator
<
Its
...
>>
{
using
iterator_category
=
forward_iterator_tag
;
using
value_type
=
typename
::
akantu
::
iterators
::
ZipIterator
<
Its
...
>::
value_type
;
using
difference_type
=
typename
::
akantu
::
iterators
::
ZipIterator
<
Its
...
>::
difference_type
;
using
pointer
=
typename
::
akantu
::
iterators
::
ZipIterator
<
Its
...
>::
pointer
;
using
reference
=
typename
::
akantu
::
iterators
::
ZipIterator
<
Its
...
>::
reference
;
};
}
// namespace std
#endif
/* AKANTU_AKA_ITERATORS_HH */
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