Remove bitfield.h

Summary:
##Changelog:

[Internal][Yoga] Remove Bitfield.h

Reviewed By: astreet

Differential Revision: D18519647

fbshipit-source-id: b46fe585d3ef5f1da7d2726b2d9f759a649be121

yoga/Bitfield.h

@@ -1,145 +0,0 @@
-/*
- * Copyright (c) Facebook, Inc. and its affiliates.
- *
- * This source code is licensed under the MIT license found in the
- * LICENSE file in the root directory of this source tree.
- */
-
-#pragma once
-
-#include <cstddef>
-#include <limits>
-#include <type_traits>
-#include <yoga/YGEnums.h>
-
-namespace facebook {
-namespace yoga {
-
-namespace detail {
-
-constexpr size_t log2ceil(size_t n) {
-  return n < 1 ? 0 : (1 + log2ceil(n / 2));
-}
-
-// The number of bits necessary to represent enums defined with YG_ENUM_SEQ_DECL
-template <typename Enum>
-constexpr size_t bitWidth() {
-  static_assert(
-      enums::count<Enum>() > 0, "Enums must have at least one entries");
-  return log2ceil(enums::count<Enum>() - 1);
-}
-
-// Number of bits needed for a boolean
-template <>
-constexpr size_t bitWidth<bool>() {
-  return 1;
-}
-
-template <typename U, typename... Ts>
-struct BitTraits {};
-
-template <typename U>
-struct BitTraits<U> {
-  // Base cases
-  static constexpr size_t width(size_t) { return 0; }
-  static constexpr size_t shift(size_t) { return 0; }
-};
-
-template <typename U, typename T, typename... Ts>
-struct BitTraits<U, T, Ts...> {
-  using Rest = BitTraits<U, Ts...>;
-
-  static constexpr size_t width(size_t idx) {
-    return idx == 0 ? bitWidth<T>() : Rest::width(idx - 1);
-  }
-
-  static constexpr size_t shift(size_t idx) {
-    return idx == 0 ? Rest::width(0) + Rest::shift(0) : Rest::shift(idx - 1);
-  }
-
-  static constexpr U mask(size_t idx) {
-    return ((U{1} << width(idx)) - 1) << shift(idx);
-  }
-};
-
-template <size_t Idx, typename T, typename... Ts>
-struct IndexedType {
-  using Type = typename IndexedType<Idx - 1, Ts...>::Type;
-};
-
-template <typename T, typename... Ts>
-struct IndexedType<0, T, Ts...> {
-  using Type = T;
-};
-
-} // namespace detail
-
-template <typename Storage, typename... Fields>
-class Bitfield {
-  static_assert(
-      std::is_integral<Storage>::value,
-      "Bitfield needs an integral storage type");
-  static_assert(
-      std::is_unsigned<Storage>::value,
-      "Bitfield needs an unsigned storage type");
-  static_assert(sizeof...(Fields) > 0, "Bitfield needs at least one member");
-
-  using BitTraits = detail::BitTraits<Storage, Fields...>;
-
-#if !defined(_MSC_VER) || _MSC_VER > 1914
-  static_assert(
-      BitTraits::shift(0) + BitTraits::width(0) <=
-          std::numeric_limits<Storage>::digits,
-      "Specified storage type is too narrow to hold all types");
-#endif
-
-  template <size_t Idx>
-  using TypeAt = typename detail::IndexedType<Idx, Fields...>::Type;
-
-  template <size_t Idx, typename Value, typename... Values>
-  static constexpr Storage initStorage(Value value, Values... values) {
-    return ((value << BitTraits::shift(Idx)) & BitTraits::mask(Idx)) |
-        initStorage<Idx + 1, Values...>(values...);
-  }
-
-  template <size_t Idx>
-  static constexpr Storage initStorage() {
-    return Storage{0};
-  }
-
-  Storage storage_ = 0;
-
-public:
-  template <size_t Idx>
-  class Ref {
-    Bitfield& bitfield_;
-
-  public:
-    Ref(Bitfield& bitfield) : bitfield_(bitfield) {}
-    Ref& operator=(TypeAt<Idx> value) {
-      bitfield_.storage_ = (bitfield_.storage_ & ~BitTraits::mask(Idx)) |
-          ((value << BitTraits::shift(Idx)) & BitTraits::mask(Idx));
-      return *this;
-    }
-    operator TypeAt<Idx>() const {
-      return const_cast<const Bitfield&>(bitfield_).at<Idx>();
-    }
-  };
-
-  constexpr Bitfield() = default;
-  constexpr Bitfield(Fields... values) : storage_{initStorage<0>(values...)} {}
-
-  template <size_t Idx>
-  constexpr TypeAt<Idx> at() const {
-    return static_cast<TypeAt<Idx>>(
-        (storage_ & BitTraits::mask(Idx)) >> BitTraits::shift(Idx));
-  }
-
-  template <size_t Idx>
-  Ref<Idx> at() {
-    return {*this};
-  }
-};
-
-} // namespace yoga
-} // namespace facebook