1// Copyright 2020 The Pigweed Authors
2//
3// Licensed under the Apache License, Version 2.0 (the "License"); you may not
4// use this file except in compliance with the License. You may obtain a copy of
5// the License at
6//
7//     https://www.apache.org/licenses/LICENSE-2.0
8//
9// Unless required by applicable law or agreed to in writing, software
10// distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
11// WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
12// License for the specific language governing permissions and limitations under
13// the License.
14#pragma once
15
16#include <iterator>
17
18#include "pw_polyfill/standard_library/namespace.h"
19
20_PW_POLYFILL_BEGIN_NAMESPACE_STD
21
22template <typename T, decltype(sizeof(0)) kSize>
23struct array {
24  using value_type = T;
25  using size_type = decltype(kSize);
26  using difference_type =
27      decltype(static_cast<int*>(nullptr) - static_cast<int*>(nullptr));
28  using reference = value_type&;
29  using const_reference = const value_type&;
30  using pointer = value_type*;
31  using const_pointer = const value_type*;
32  using iterator = T*;
33  using const_iterator = const T*;
34  using reverse_iterator = std::reverse_iterator<iterator>;
35  using const_reverse_iterator = std::reverse_iterator<const_iterator>;
36
37  // NOT IMPLEMENTED: at() does not bounds checking.
38  constexpr reference at(size_type index) { return data()[index]; }
39  constexpr const_reference at(size_type index) const { return data()[index]; }
40
41  constexpr reference operator[](size_type index) { return data()[index]; }
42  constexpr const_reference operator[](size_type index) const {
43    return data()[index];
44  }
45
46  constexpr reference front() { return data()[0]; }
47  constexpr const_reference front() const { return data()[0]; }
48
49  constexpr reference back() {
50    static_assert(kSize > 0);
51    return data()[size() - 1];
52  }
53  constexpr const_reference back() const {
54    static_assert(kSize > 0);
55    return data()[size() - 1];
56  }
57
58  constexpr pointer data() noexcept {
59    static_assert(kSize > 0);
60    return __data;
61  }
62  constexpr const_pointer data() const noexcept {
63    static_assert(kSize > 0);
64    return __data;
65  }
66
67  constexpr iterator begin() noexcept { return data(); }
68  constexpr const_iterator begin() const noexcept { return data(); }
69  constexpr const_iterator cbegin() const noexcept { return begin(); }
70
71  constexpr iterator end() noexcept { return data() + kSize; }
72  constexpr const_iterator end() const noexcept { return data() + kSize; }
73  constexpr const_iterator cend() const noexcept { return end(); }
74
75  // NOT IMPLEMENTED
76  constexpr reverse_iterator rbegin() noexcept;
77  constexpr const_reverse_iterator rbegin() const noexcept;
78  constexpr const_reverse_iterator crbegin() const noexcept;
79
80  // NOT IMPLEMENTED
81  constexpr reverse_iterator rend() noexcept;
82  constexpr const_reverse_iterator rend() const noexcept;
83  constexpr const_reverse_iterator crend() const noexcept;
84
85  [[nodiscard]] constexpr bool empty() const noexcept { return kSize == 0u; }
86
87  constexpr size_type size() const noexcept { return kSize; }
88
89  constexpr size_type max_size() const noexcept { return size(); }
90
91  constexpr void fill(const T& value) {
92    for (T& array_value : __data) {
93      array_value = value;
94    }
95  }
96
97  // NOT IMPLEMENTED
98  constexpr void swap(array& other) noexcept;
99
100  T __data[kSize];
101};
102
103// NOT IMPLEMENTED: comparison operators, get, swap, tuple specializations
104
105_PW_POLYFILL_END_NAMESPACE_STD
106