You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
141 lines
4.3 KiB
141 lines
4.3 KiB
/* |
|
* Copyright 2008-2012 NVIDIA Corporation |
|
* |
|
* Licensed under the Apache License, Version 2.0 (the "License"); |
|
* you may not use this file except in compliance with the License. |
|
* You may obtain a copy of the License at |
|
* |
|
* http://www.apache.org/licenses/LICENSE-2.0 |
|
* |
|
* Unless required by applicable law or agreed to in writing, software |
|
* distributed under the License is distributed on an "AS IS" BASIS, |
|
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
|
* See the License for the specific language governing permissions and |
|
* limitations under the License. |
|
*/ |
|
|
|
#pragma once |
|
|
|
#include <thrust/iterator/counting_iterator.h> |
|
#include <thrust/iterator/iterator_traits.h> |
|
#include <thrust/detail/numeric_traits.h> |
|
#include <thrust/detail/type_traits.h> |
|
#include <cstddef> |
|
|
|
namespace thrust |
|
{ |
|
|
|
// forward declaration of counting_iterator |
|
template <typename Incrementable, typename System, typename Traversal, typename Difference> |
|
class counting_iterator; |
|
|
|
namespace detail |
|
{ |
|
|
|
template <typename Incrementable, typename System, typename Traversal, typename Difference> |
|
struct counting_iterator_base |
|
{ |
|
typedef typename thrust::detail::eval_if< |
|
// use any_system_tag if we are given use_default |
|
thrust::detail::is_same<System,use_default>::value, |
|
thrust::detail::identity_<thrust::any_system_tag>, |
|
thrust::detail::identity_<System> |
|
>::type system; |
|
|
|
typedef typename thrust::detail::ia_dflt_help< |
|
Traversal, |
|
thrust::detail::eval_if< |
|
thrust::detail::is_numeric<Incrementable>::value, |
|
thrust::detail::identity_<random_access_traversal_tag>, |
|
thrust::iterator_traversal<Incrementable> |
|
> |
|
>::type traversal; |
|
|
|
// unlike Boost, we explicitly use std::ptrdiff_t as the difference type |
|
// for floating point counting_iterators |
|
typedef typename thrust::detail::ia_dflt_help< |
|
Difference, |
|
thrust::detail::eval_if< |
|
thrust::detail::is_numeric<Incrementable>::value, |
|
thrust::detail::eval_if< |
|
thrust::detail::is_integral<Incrementable>::value, |
|
thrust::detail::numeric_difference<Incrementable>, |
|
thrust::detail::identity_<std::ptrdiff_t> |
|
>, |
|
thrust::iterator_difference<Incrementable> |
|
> |
|
>::type difference; |
|
|
|
// our implementation departs from Boost's in that counting_iterator::dereference |
|
// returns a copy of its counter, rather than a reference to it. returning a reference |
|
// to the internal state of an iterator causes subtle bugs (consider the temporary |
|
// iterator created in the expression *(iter + i) ) and has no compelling use case |
|
typedef thrust::iterator_adaptor< |
|
counting_iterator<Incrementable, System, Traversal, Difference>, // self |
|
Incrementable, // Base |
|
Incrementable, // XXX we may need to pass const here as Boost does |
|
system, |
|
traversal, |
|
Incrementable, |
|
difference |
|
> type; |
|
}; // end counting_iterator_base |
|
|
|
|
|
template<typename Difference, typename Incrementable1, typename Incrementable2> |
|
struct iterator_distance |
|
{ |
|
__host__ __device__ |
|
static Difference distance(Incrementable1 x, Incrementable2 y) |
|
{ |
|
return y - x; |
|
} |
|
}; |
|
|
|
|
|
template<typename Difference, typename Incrementable1, typename Incrementable2> |
|
struct number_distance |
|
{ |
|
__host__ __device__ |
|
static Difference distance(Incrementable1 x, Incrementable2 y) |
|
{ |
|
return static_cast<Difference>(numeric_distance(x,y)); |
|
} |
|
}; |
|
|
|
|
|
template<typename Difference, typename Incrementable1, typename Incrementable2, typename Enable = void> |
|
struct counting_iterator_equal |
|
{ |
|
__host__ __device__ |
|
static bool equal(Incrementable1 x, Incrementable2 y) |
|
{ |
|
return x == y; |
|
} |
|
}; |
|
|
|
|
|
// specialization for floating point equality |
|
template<typename Difference, typename Incrementable1, typename Incrementable2> |
|
struct counting_iterator_equal< |
|
Difference, |
|
Incrementable1, |
|
Incrementable2, |
|
typename thrust::detail::enable_if< |
|
thrust::detail::is_floating_point<Incrementable1>::value || |
|
thrust::detail::is_floating_point<Incrementable2>::value |
|
>::type |
|
> |
|
{ |
|
__host__ __device__ |
|
static bool equal(Incrementable1 x, Incrementable2 y) |
|
{ |
|
typedef number_distance<Difference,Incrementable1,Incrementable2> d; |
|
return d::distance(x,y) == 0; |
|
} |
|
}; |
|
|
|
|
|
} // end detail |
|
} // end thrust |
|
|
|
|