libc/src/__support/CPP/array.h

   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
  17 namespace LIBC_NAMESPACE_DECL {
  18 namespace cpp {
  19
  20 template <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