1/*
2 Copyright (c) 2017-2019 Intel Corporation
3
4 Licensed under the Apache License, Version 2.0 (the "License");
5 you may not use this file except in compliance with the License.
6 You may obtain a copy of the License at
7
8 http://www.apache.org/licenses/LICENSE-2.0
9
10 Unless required by applicable law or agreed to in writing, software
11 distributed under the License is distributed on an "AS IS" BASIS,
12 WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 See the License for the specific language governing permissions and
14 limitations under the License.
15*/
16
17#ifndef __TBB_blocked_rangeNd_H
18#define __TBB_blocked_rangeNd_H
19
20#if ! TBB_PREVIEW_BLOCKED_RANGE_ND
21 #error Set TBB_PREVIEW_BLOCKED_RANGE_ND to include blocked_rangeNd.h
22#endif
23
24#include "tbb_config.h"
25
26// tbb::blocked_rangeNd requires C++11 support
27#if __TBB_CPP11_PRESENT && __TBB_CPP11_ARRAY_PRESENT && __TBB_CPP11_TEMPLATE_ALIASES_PRESENT
28
29#include "internal/_template_helpers.h" // index_sequence, make_index_sequence
30
31#include <array>
32#include <algorithm> // std::any_of
33#include <type_traits> // std::is_same, std::enable_if
34
35#include "tbb/blocked_range.h"
36
37namespace tbb {
38namespace internal {
39
40/*
41 The blocked_rangeNd_impl uses make_index_sequence<N> to automatically generate a ctor with
42 exactly N arguments of the type tbb::blocked_range<Value>. Such ctor provides an opportunity
43 to use braced-init-list parameters to initialize each dimension.
44 Use of parameters, whose representation is a braced-init-list, but they're not
45 std::initializer_list or a reference to one, produces a non-deduced context
46 within template argument deduction.
47
48 NOTE: blocked_rangeNd must be exactly a templated alias to the blocked_rangeNd_impl
49 (and not e.g. a derived class), otherwise it would need to declare its own ctor
50 facing the same problem that the impl class solves.
51*/
52
53template<typename Value, unsigned int N, typename = make_index_sequence<N>>
54class blocked_rangeNd_impl;
55
56template<typename Value, unsigned int N, std::size_t... Is>
57class blocked_rangeNd_impl<Value, N, index_sequence<Is...>> {
58public:
59 //! Type of a value.
60 using value_type = Value;
61
62private:
63
64 //! Helper type to construct range with N tbb::blocked_range<value_type> objects.
65 template<std::size_t>
66 using dim_type_helper = tbb::blocked_range<value_type>;
67
68public:
69 blocked_rangeNd_impl() = delete;
70
71 //! Constructs N-dimensional range over N half-open intervals each represented as tbb::blocked_range<Value>.
72 blocked_rangeNd_impl(const dim_type_helper<Is>&... args) : my_dims{ {args...} } {}
73
74 //! Dimensionality of a range.
75 static constexpr unsigned int ndims() { return N; }
76
77 //! Range in certain dimension.
78 const tbb::blocked_range<value_type>& dim(unsigned int dimension) const {
79 __TBB_ASSERT(dimension < N, "out of bound");
80 return my_dims[dimension];
81 }
82
83 //------------------------------------------------------------------------
84 // Methods that implement Range concept
85 //------------------------------------------------------------------------
86
87 //! True if at least one dimension is empty.
88 bool empty() const {
89 return std::any_of(my_dims.begin(), my_dims.end(), [](const tbb::blocked_range<value_type>& d) {
90 return d.empty();
91 });
92 }
93
94 //! True if at least one dimension is divisible.
95 bool is_divisible() const {
96 return std::any_of(my_dims.begin(), my_dims.end(), [](const tbb::blocked_range<value_type>& d) {
97 return d.is_divisible();
98 });
99 }
100
101#if __TBB_USE_PROPORTIONAL_SPLIT_IN_BLOCKED_RANGES
102 //! Static field to support proportional split.
103 static const bool is_splittable_in_proportion = true;
104
105 blocked_rangeNd_impl(blocked_rangeNd_impl& r, proportional_split proportion) : my_dims(r.my_dims) {
106 do_split(r, proportion);
107 }
108#endif
109
110 blocked_rangeNd_impl(blocked_rangeNd_impl& r, split proportion) : my_dims(r.my_dims) {
111 do_split(r, proportion);
112 }
113
114private:
115 __TBB_STATIC_ASSERT(N != 0, "zero dimensional blocked_rangeNd can't be constructed");
116
117 //! Ranges in each dimension.
118 std::array<tbb::blocked_range<value_type>, N> my_dims;
119
120 template<typename split_type>
121 void do_split(blocked_rangeNd_impl& r, split_type proportion) {
122 __TBB_STATIC_ASSERT((is_same_type<split_type, split>::value
123 || is_same_type<split_type, proportional_split>::value),
124 "type of split object is incorrect");
125 __TBB_ASSERT(r.is_divisible(), "can't split not divisible range");
126
127 auto my_it = std::max_element(my_dims.begin(), my_dims.end(), [](const tbb::blocked_range<value_type>& first, const tbb::blocked_range<value_type>& second) {
128 return (first.size() * second.grainsize() < second.size() * first.grainsize());
129 });
130
131 auto r_it = r.my_dims.begin() + (my_it - my_dims.begin());
132
133 my_it->my_begin = tbb::blocked_range<value_type>::do_split(*r_it, proportion);
134
135 // (!(my_it->my_begin < r_it->my_end) && !(r_it->my_end < my_it->my_begin)) equals to
136 // (my_it->my_begin == r_it->my_end), but we can't use operator== due to Value concept
137 __TBB_ASSERT(!(my_it->my_begin < r_it->my_end) && !(r_it->my_end < my_it->my_begin),
138 "blocked_range has been split incorrectly");
139 }
140};
141
142} // namespace internal
143
144template<typename Value, unsigned int N>
145using blocked_rangeNd = internal::blocked_rangeNd_impl<Value, N>;
146
147} // namespace tbb
148
149#endif /* __TBB_CPP11_PRESENT && __TBB_CPP11_ARRAY_PRESENT && __TBB_CPP11_TEMPLATE_ALIASES_PRESENT */
150#endif /* __TBB_blocked_rangeNd_H */
151