1 files changed, 88 insertions, 0 deletions
diff --git a/mfbt/Array.h b/mfbt/Array.h
new file mode 100644
index 000000000..72b89ede1
--- /dev/null
+++ b/mfbt/Array.h
@@ -0,0 +1,88 @@
+/* -*- 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 "mozilla/Assertions.h"
+#include "mozilla/Attributes.h"
+#include "mozilla/Move.h"
+#include "mozilla/ReverseIterator.h"
+
+#include <stddef.h>
+
+namespace mozilla {
+
+template<typename T, size_t Length>
+class Array
+{
+  T mArr[Length];
+
+public:
+  Array() {}
+
+  template <typename... Args>
+  MOZ_IMPLICIT Array(Args&&... aArgs)
+    : mArr{mozilla::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)
+  {
+    MOZ_ASSERT(aIndex < Length);
+    return mArr[aIndex];
+  }
+
+  const T& operator[](size_t aIndex) const
+  {
+    MOZ_ASSERT(aIndex < Length);
+    return mArr[aIndex];
+  }
+
+  typedef T*                        iterator;
+  typedef const T*                  const_iterator;
+  typedef ReverseIterator<T*>       reverse_iterator;
+  typedef ReverseIterator<const T*> const_reverse_iterator;
+
+  // Methods for range-based for loops.
+  iterator begin() { return mArr; }
+  const_iterator begin() const { return mArr; }
+  const_iterator cbegin() const { return begin(); }
+  iterator end() { return mArr + Length; }
+  const_iterator end() const { return mArr + Length; }
+  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");
+  }
+};
+
+}  /* namespace mozilla */
+
+#endif /* mozilla_Array_h */