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+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/* A compile-time constant-length array with bounds-checking assertions. */
+
+#ifndef mozilla_Array_h
+#define mozilla_Array_h
+
+#include <stddef.h>
+
+#include <iterator>
+#include <ostream>
+#include <utility>
+
+#include "mozilla/Assertions.h"
+#include "mozilla/Attributes.h"
+#include "mozilla/Likely.h"
+
+namespace mozilla {
+
+template <typename T, size_t _Length>
+class Array {
+ T mArr[_Length];
+
+ public:
+ using ElementType = T;
+ static constexpr size_t Length = _Length;
+
+ constexpr Array() = default;
+
+ template <typename... Args>
+ MOZ_IMPLICIT constexpr Array(Args&&... aArgs)
+ : mArr{std::forward<Args>(aArgs)...} {
+ static_assert(sizeof...(aArgs) == Length,
+ "The number of arguments should be equal to the template "
+ "parameter Length");
+ }
+
+ T& operator[](size_t aIndex) {
+ if (MOZ_UNLIKELY(aIndex >= Length)) {
+ detail::InvalidArrayIndex_CRASH(aIndex, Length);
+ }
+ return mArr[aIndex];
+ }
+
+ const T& operator[](size_t aIndex) const {
+ if (MOZ_UNLIKELY(aIndex >= Length)) {
+ detail::InvalidArrayIndex_CRASH(aIndex, Length);
+ }
+ return mArr[aIndex];
+ }
+
+ bool operator==(const Array<T, Length>& aOther) const {
+ for (size_t i = 0; i < Length; i++) {
+ if (mArr[i] != aOther[i]) {
+ return false;
+ }
+ }
+ return true;
+ }
+
+ typedef T* iterator;
+ typedef const T* const_iterator;
+ typedef std::reverse_iterator<T*> reverse_iterator;
+ typedef std::reverse_iterator<const T*> const_reverse_iterator;
+
+ // Methods for range-based for loops.
+ iterator begin() { return mArr; }
+ constexpr const_iterator begin() const { return mArr; }
+ constexpr const_iterator cbegin() const { return begin(); }
+ iterator end() { return mArr + Length; }
+ constexpr const_iterator end() const { return mArr + Length; }
+ constexpr const_iterator cend() const { return end(); }
+
+ // Methods for reverse iterating.
+ reverse_iterator rbegin() { return reverse_iterator(end()); }
+ const_reverse_iterator rbegin() const {
+ return const_reverse_iterator(end());
+ }
+ const_reverse_iterator crbegin() const { return rbegin(); }
+ reverse_iterator rend() { return reverse_iterator(begin()); }
+ const_reverse_iterator rend() const {
+ return const_reverse_iterator(begin());
+ }
+ const_reverse_iterator crend() const { return rend(); }
+};
+
+template <typename T>
+class Array<T, 0> {
+ public:
+ T& operator[](size_t aIndex) { MOZ_CRASH("indexing into zero-length array"); }
+
+ const T& operator[](size_t aIndex) const {
+ MOZ_CRASH("indexing into zero-length array");
+ }
+};
+
+// MOZ_DBG support
+
+template <typename T, size_t Length>
+std::ostream& operator<<(std::ostream& aOut, const Array<T, Length>& aArray) {
+ return aOut << Span(aArray);
+}
+
+} /* namespace mozilla */
+
+#endif /* mozilla_Array_h */