From 5f8de423f190bbb79a62f804151bc24824fa32d8 Mon Sep 17 00:00:00 2001 From: "Matt A. Tobin" Date: Fri, 2 Feb 2018 04:16:08 -0500 Subject: Add m-esr52 at 52.6.0 --- mfbt/EnumeratedArray.h | 110 +++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 110 insertions(+) create mode 100644 mfbt/EnumeratedArray.h (limited to 'mfbt/EnumeratedArray.h') diff --git a/mfbt/EnumeratedArray.h b/mfbt/EnumeratedArray.h new file mode 100644 index 000000000..9e74b7724 --- /dev/null +++ b/mfbt/EnumeratedArray.h @@ -0,0 +1,110 @@ +/* -*- 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/. */ + +/* EnumeratedArray is like Array, but indexed by a typed enum. */ + +#ifndef mozilla_EnumeratedArray_h +#define mozilla_EnumeratedArray_h + +#include "mozilla/Array.h" +#include "mozilla/Move.h" + +namespace mozilla { + +/** + * EnumeratedArray is a fixed-size array container for use when an + * array is indexed by a specific enum class. + * + * This provides type safety by guarding at compile time against accidentally + * indexing such arrays with unrelated values. This also removes the need + * for manual casting when using a typed enum value to index arrays. + * + * Aside from the typing of indices, EnumeratedArray is similar to Array. + * + * Example: + * + * enum class AnimalSpecies { + * Cow, + * Sheep, + * Count + * }; + * + * EnumeratedArray headCount; + * + * headCount[AnimalSpecies::Cow] = 17; + * headCount[AnimalSpecies::Sheep] = 30; + * + */ +template +class EnumeratedArray +{ +public: + static const size_t kSize = size_t(SizeAsEnumValue); + +private: + typedef Array ArrayType; + + ArrayType mArray; + +public: + EnumeratedArray() {} + + template + MOZ_IMPLICIT EnumeratedArray(Args&&... aArgs) + : mArray{mozilla::Forward(aArgs)...} + {} + + explicit EnumeratedArray(const EnumeratedArray& aOther) + { + for (size_t i = 0; i < kSize; i++) { + mArray[i] = aOther.mArray[i]; + } + } + + EnumeratedArray(EnumeratedArray&& aOther) + { + for (size_t i = 0; i < kSize; i++) { + mArray[i] = Move(aOther.mArray[i]); + } + } + + ValueType& operator[](IndexType aIndex) + { + return mArray[size_t(aIndex)]; + } + + const ValueType& operator[](IndexType aIndex) const + { + return mArray[size_t(aIndex)]; + } + + typedef typename ArrayType::iterator iterator; + typedef typename ArrayType::const_iterator const_iterator; + typedef typename ArrayType::reverse_iterator reverse_iterator; + typedef typename ArrayType::const_reverse_iterator const_reverse_iterator; + + // Methods for range-based for loops. + iterator begin() { return mArray.begin(); } + const_iterator begin() const { return mArray.begin(); } + const_iterator cbegin() const { return mArray.cbegin(); } + iterator end() { return mArray.end(); } + const_iterator end() const { return mArray.end(); } + const_iterator cend() const { return mArray.cend(); } + + // Methods for reverse iterating. + reverse_iterator rbegin() { return mArray.rbegin(); } + const_reverse_iterator rbegin() const { return mArray.rbegin(); } + const_reverse_iterator crbegin() const { return mArray.crbegin(); } + reverse_iterator rend() { return mArray.rend(); } + const_reverse_iterator rend() const { return mArray.rend(); } + const_reverse_iterator crend() const { return mArray.crend(); } +}; + +} // namespace mozilla + +#endif // mozilla_EnumeratedArray_h -- cgit v1.2.3