michael@0: /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
michael@0: /* vim: set ts=8 sts=2 et sw=2 tw=80: */
michael@0: /* This Source Code Form is subject to the terms of the Mozilla Public
michael@0:  * License, v. 2.0. If a copy of the MPL was not distributed with this
michael@0:  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
michael@0: 
michael@0: /* EnumeratedArray is like Array, but indexed by a typed enum. */
michael@0: 
michael@0: #ifndef mozilla_EnumeratedArray_h
michael@0: #define mozilla_EnumeratedArray_h
michael@0: 
michael@0: #include "mozilla/Array.h"
michael@0: #include "mozilla/TypedEnum.h"
michael@0: 
michael@0: namespace mozilla {
michael@0: 
michael@0: /**
michael@0:  * EnumeratedArray is a fixed-size array container for use when an
michael@0:  * array is indexed by a specific enum class, as currently implemented
michael@0:  * by MOZ_BEGIN_ENUM_CLASS.
michael@0:  *
michael@0:  * This provides type safety by guarding at compile time against accidentally
michael@0:  * indexing such arrays with unrelated values. This also removes the need
michael@0:  * for manual casting when using a typed enum value to index arrays.
michael@0:  *
michael@0:  * Aside from the typing of indices, EnumeratedArray is similar to Array.
michael@0:  *
michael@0:  * Example:
michael@0:  *
michael@0:  *   MOZ_BEGIN_ENUM_CLASS(AnimalSpecies)
michael@0:  *     Cow,
michael@0:  *     Sheep,
michael@0:  *     Count
michael@0:  *   MOZ_END_ENUM_CLASS(AnimalSpecies)
michael@0:  *
michael@0:  *   EnumeratedArray<AnimalSpecies, AnimalSpecies::Count, int> headCount;
michael@0:  *
michael@0:  *   headCount[AnimalSpecies::Cow] = 17;
michael@0:  *   headCount[AnimalSpecies::Sheep] = 30;
michael@0:  *
michael@0:  */
michael@0: template<typename IndexType,
michael@0:          MOZ_TEMPLATE_ENUM_CLASS_ENUM_TYPE(IndexType) SizeAsEnumValue,
michael@0:          typename ValueType>
michael@0: class EnumeratedArray
michael@0: {
michael@0:   public:
michael@0:     static const size_t Size = size_t(SizeAsEnumValue);
michael@0: 
michael@0:   private:
michael@0:     Array<ValueType, Size> mArray;
michael@0: 
michael@0:   public:
michael@0:     EnumeratedArray() {}
michael@0: 
michael@0:     explicit EnumeratedArray(const EnumeratedArray& aOther)
michael@0:     {
michael@0:       for (size_t i = 0; i < Size; i++)
michael@0:         mArray[i] = aOther.mArray[i];
michael@0:     }
michael@0: 
michael@0:     explicit EnumeratedArray(const ValueType (&aOther)[Size])
michael@0:     {
michael@0:       for (size_t i = 0; i < Size; i++)
michael@0:         mArray[i] = aOther[i];
michael@0:     }
michael@0: 
michael@0:     ValueType& operator[](IndexType aIndex)
michael@0:     {
michael@0:       return mArray[size_t(aIndex)];
michael@0:     }
michael@0: 
michael@0:     const ValueType& operator[](IndexType aIndex) const
michael@0:     {
michael@0:       return mArray[size_t(aIndex)];
michael@0:     }
michael@0: };
michael@0: 
michael@0: } // namespace mozilla
michael@0: 
michael@0: #endif // mozilla_EnumeratedArray_h