1//===-- A self contained equivalent of std::array ---------------*- C++ -*-===//
 2//
 3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 4// See https://llvm.org/LICENSE.txt for license information.
 5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 6//
 7//===----------------------------------------------------------------------===//
 8
 9#ifndef LLVM_LIBC_SRC___SUPPORT_CPP_ARRAY_H
10#define LLVM_LIBC_SRC___SUPPORT_CPP_ARRAY_H
11
12#include "src/__support/CPP/iterator.h" // reverse_iterator
13#include "src/__support/macros/attributes.h"
14#include "src/__support/macros/config.h"
15#include <stddef.h> // For size_t.
16
17namespace LIBC_NAMESPACE_DECL {
18namespace cpp {
19
20template <class T, size_t N> struct array {
21  static_assert(N != 0,
22                "Cannot create a LIBC_NAMESPACE::cpp::array of size 0.");
23
24  T Data[N];
25  using value_type = T;
26  using iterator = T *;
27  using const_iterator = const T *;
28  using reverse_iterator = cpp::reverse_iterator<iterator>;
29  using const_reverse_iterator = cpp::reverse_iterator<const_iterator>;
30
31  LIBC_INLINE constexpr T *data() { return Data; }
32  LIBC_INLINE constexpr const T *data() const { return Data; }
33
34  LIBC_INLINE constexpr T &front() { return Data[0]; }
35  LIBC_INLINE constexpr const T &front() const { return Data[0]; }
36
37  LIBC_INLINE constexpr T &back() { return Data[N - 1]; }
38  LIBC_INLINE constexpr const T &back() const { return Data[N - 1]; }
39
40  LIBC_INLINE constexpr T &operator[](size_t Index) { return Data[Index]; }
41
42  LIBC_INLINE constexpr const T &operator[](size_t Index) const {
43    return Data[Index];
44  }
45
46  LIBC_INLINE constexpr size_t size() const { return N; }
47
48  LIBC_INLINE constexpr bool empty() const { return N == 0; }
49
50  LIBC_INLINE constexpr iterator begin() { return Data; }
51  LIBC_INLINE constexpr const_iterator begin() const { return Data; }
52  LIBC_INLINE constexpr const_iterator cbegin() const { return begin(); }
53
54  LIBC_INLINE constexpr iterator end() { return Data + N; }
55  LIBC_INLINE constexpr const_iterator end() const { return Data + N; }
56  LIBC_INLINE constexpr const_iterator cend() const { return end(); }
57
58  LIBC_INLINE constexpr reverse_iterator rbegin() {
59    return reverse_iterator{end()};
60  }
61  LIBC_INLINE constexpr const_reverse_iterator rbegin() const {
62    return const_reverse_iterator{end()};
63  }
64  LIBC_INLINE constexpr const_reverse_iterator crbegin() const {
65    return rbegin();
66  }
67
68  LIBC_INLINE constexpr reverse_iterator rend() {
69    return reverse_iterator{begin()};
70  }
71  LIBC_INLINE constexpr const_reverse_iterator rend() const {
72    return const_reverse_iterator{begin()};
73  }
74  LIBC_INLINE constexpr const_reverse_iterator crend() const { return rend(); }
75};
76
77} // namespace cpp
78} // namespace LIBC_NAMESPACE_DECL
79
80#endif // LLVM_LIBC_SRC___SUPPORT_CPP_ARRAY_H