mirror of
https://github.com/mozilla/gecko-dev.git
synced 2024-11-23 04:41:11 +00:00
e54774d573
Namely std::size, std::end and std::size. This drops C support for MOZ_ARRAY_LENGTH but it wasn't used anyway. Differential Revision: https://phabricator.services.mozilla.com/D224611
100 lines
3.2 KiB
C++
100 lines
3.2 KiB
C++
/* -*- 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 <utility>
|
|
|
|
#include "mozilla/Array.h"
|
|
#include "EnumTypeTraits.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<AnimalSpecies, int, AnimalSpecies::Count> headCount;
|
|
*
|
|
* headCount[AnimalSpecies::Cow] = 17;
|
|
* headCount[AnimalSpecies::Sheep] = 30;
|
|
*
|
|
* If the enum class has contiguous values and provides a specialization of
|
|
* mozilla::MaxContiguousEnumValue then the size will be calculated as the max
|
|
* value + 1.
|
|
*/
|
|
template <typename Enum, typename ValueType,
|
|
size_t Size = ContiguousEnumSize<Enum>::value>
|
|
class EnumeratedArray {
|
|
private:
|
|
static_assert(UnderlyingValue(MinContiguousEnumValue<Enum>::value) == 0,
|
|
"All indexes would need to be corrected if min != 0");
|
|
|
|
using ArrayType = Array<ValueType, Size>;
|
|
|
|
ArrayType mArray;
|
|
|
|
public:
|
|
constexpr EnumeratedArray() = default;
|
|
|
|
template <typename... Args>
|
|
MOZ_IMPLICIT constexpr EnumeratedArray(Args&&... aArgs)
|
|
: mArray{std::forward<Args>(aArgs)...} {}
|
|
|
|
constexpr ValueType& operator[](Enum aIndex) {
|
|
return mArray[size_t(aIndex)];
|
|
}
|
|
|
|
constexpr const ValueType& operator[](Enum aIndex) const {
|
|
return mArray[size_t(aIndex)];
|
|
}
|
|
|
|
using iterator = typename ArrayType::iterator;
|
|
using const_iterator = typename ArrayType::const_iterator;
|
|
using reverse_iterator = typename ArrayType::reverse_iterator;
|
|
using const_reverse_iterator = typename ArrayType::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(); }
|
|
|
|
// Method for std::size.
|
|
constexpr size_t size() const { return mArray.size(); }
|
|
|
|
// 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
|