mfbt/TypedEnumBits.h

   1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* vim: set ts=8 sts=2 et sw=2 tw=80: */
   3 /* This Source Code Form is subject to the terms of the Mozilla Public
   4  * License, v. 2.0. If a copy of the MPL was not distributed with this
   5  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   6
   7 /*
   8  * MOZ_MAKE_ENUM_CLASS_BITWISE_OPERATORS allows using a typed enum as bit flags.
   9  */
  10
  11 #ifndef mozilla_TypedEnumBits_h
  12 #define mozilla_TypedEnumBits_h
  13
  14 #include "mozilla/IntegerTypeTraits.h"
  15 #include "mozilla/TypedEnumInternal.h"
  16
  17 namespace mozilla {
  18
  19 #define MOZ_CASTABLETYPEDENUMRESULT_BINOP(Op, OtherType, ReturnType) \
  20 template<typename E> \
  21 MOZ_CONSTEXPR ReturnType \
  22 operator Op(const OtherType& aE, const CastableTypedEnumResult<E>& aR) \
  23 { \
  24   return ReturnType(aE Op OtherType(aR)); \
  25 } \
  26 template<typename E> \
  27 MOZ_CONSTEXPR ReturnType \
  28 operator Op(const CastableTypedEnumResult<E>& aR, const OtherType& aE) \
  29 { \
  30   return ReturnType(OtherType(aR) Op aE); \
  31 } \
  32 template<typename E> \
  33 MOZ_CONSTEXPR ReturnType \
  34 operator Op(const CastableTypedEnumResult<E>& aR1, \
  35             const CastableTypedEnumResult<E>& aR2) \
  36 { \
  37   return ReturnType(OtherType(aR1) Op OtherType(aR2)); \
  38 }
  39
  40 MOZ_CASTABLETYPEDENUMRESULT_BINOP(|, E, CastableTypedEnumResult<E>)
  41 MOZ_CASTABLETYPEDENUMRESULT_BINOP(&, E, CastableTypedEnumResult<E>)
  42 MOZ_CASTABLETYPEDENUMRESULT_BINOP(^, E, CastableTypedEnumResult<E>)
  43 MOZ_CASTABLETYPEDENUMRESULT_BINOP(==, E, bool)
  44 MOZ_CASTABLETYPEDENUMRESULT_BINOP(!=, E, bool)
  45 MOZ_CASTABLETYPEDENUMRESULT_BINOP(||, bool, bool)
  46 MOZ_CASTABLETYPEDENUMRESULT_BINOP(&&, bool, bool)
  47
  48 template <typename E>
  49 MOZ_CONSTEXPR CastableTypedEnumResult<E>
  50 operator ~(const CastableTypedEnumResult<E>& aR)
  51 {
  52   return CastableTypedEnumResult<E>(~(E(aR)));
  53 }
  54
  55 #define MOZ_CASTABLETYPEDENUMRESULT_COMPOUND_ASSIGN_OP(Op) \
  56 template<typename E> \
  57 E& \
  58 operator Op(E& aR1, \
  59             const CastableTypedEnumResult<E>& aR2) \
  60 { \
  61   return aR1 Op E(aR2); \
  62 }
  63
  64 MOZ_CASTABLETYPEDENUMRESULT_COMPOUND_ASSIGN_OP(&=)
  65 MOZ_CASTABLETYPEDENUMRESULT_COMPOUND_ASSIGN_OP(|=)
  66 MOZ_CASTABLETYPEDENUMRESULT_COMPOUND_ASSIGN_OP(^=)
  67
  68 #undef MOZ_CASTABLETYPEDENUMRESULT_COMPOUND_ASSIGN_OP
  69
  70 #undef MOZ_CASTABLETYPEDENUMRESULT_BINOP
  71
  72 #ifndef MOZ_HAVE_CXX11_STRONG_ENUMS
  73
  74 #define MOZ_CASTABLETYPEDENUMRESULT_BINOP_EXTRA_NON_CXX11(Op, ReturnType) \
  75 template<typename E> \
  76 MOZ_CONSTEXPR ReturnType \
  77 operator Op(typename E::Enum aE, const CastableTypedEnumResult<E>& aR) \
  78 { \
  79   return ReturnType(aE Op E(aR)); \
  80 } \
  81 template<typename E> \
  82 MOZ_CONSTEXPR ReturnType \
  83 operator Op(const CastableTypedEnumResult<E>& aR, typename E::Enum aE) \
  84 { \
  85   return ReturnType(E(aR) Op aE); \
  86 }
  87
  88 MOZ_CASTABLETYPEDENUMRESULT_BINOP_EXTRA_NON_CXX11(|, CastableTypedEnumResult<E>)
  89 MOZ_CASTABLETYPEDENUMRESULT_BINOP_EXTRA_NON_CXX11(&, CastableTypedEnumResult<E>)
  90 MOZ_CASTABLETYPEDENUMRESULT_BINOP_EXTRA_NON_CXX11(^, CastableTypedEnumResult<E>)
  91 MOZ_CASTABLETYPEDENUMRESULT_BINOP_EXTRA_NON_CXX11(==, bool)
  92 MOZ_CASTABLETYPEDENUMRESULT_BINOP_EXTRA_NON_CXX11(!=, bool)
  93
  94 #undef MOZ_CASTABLETYPEDENUMRESULT_BINOP_EXTRA_NON_CXX11
  95
  96 #endif // not MOZ_HAVE_CXX11_STRONG_ENUMS
  97
  98 namespace detail {
  99 template<typename E>
 100 struct UnsignedIntegerTypeForEnum
 101   : UnsignedStdintTypeForSize<sizeof(E)>
 102 {};
 103 }
 104
 105 } // namespace mozilla
 106
 107 #define MOZ_MAKE_ENUM_CLASS_BINOP_IMPL(Name, Op) \
 108    inline MOZ_CONSTEXPR mozilla::CastableTypedEnumResult<Name> \
 109    operator Op(Name a, Name b) \
 110    { \
 111      typedef mozilla::CastableTypedEnumResult<Name> Result; \
 112      typedef mozilla::detail::UnsignedIntegerTypeForEnum<Name>::Type U; \
 113      return Result(Name(U(a) Op U(b))); \
 114    } \
 115  \
 116    inline Name& \
 117    operator Op##=(Name& a, Name b) \
 118    { \
 119      return a = a Op b; \
 120    }
 121
 122 #define MOZ_MAKE_ENUM_CLASS_OPS_IMPL(Name) \
 123    MOZ_MAKE_ENUM_CLASS_BINOP_IMPL(Name, |) \
 124    MOZ_MAKE_ENUM_CLASS_BINOP_IMPL(Name, &) \
 125    MOZ_MAKE_ENUM_CLASS_BINOP_IMPL(Name, ^) \
 126    inline MOZ_CONSTEXPR mozilla::CastableTypedEnumResult<Name> \
 127    operator~(Name a) \
 128    { \
 129      typedef mozilla::CastableTypedEnumResult<Name> Result; \
 130      typedef mozilla::detail::UnsignedIntegerTypeForEnum<Name>::Type U; \
 131      return Result(Name(~(U(a)))); \
 132    }
 133
 134 #ifndef MOZ_HAVE_CXX11_STRONG_ENUMS
 135 #  define MOZ_MAKE_ENUM_CLASS_BITWISE_BINOP_EXTRA_NON_CXX11(Name, Op) \
 136      inline MOZ_CONSTEXPR mozilla::CastableTypedEnumResult<Name> \
 137      operator Op(Name a, Name::Enum b) \
 138      { \
 139        return a Op Name(b); \
 140      } \
 141  \
 142      inline MOZ_CONSTEXPR mozilla::CastableTypedEnumResult<Name> \
 143      operator Op(Name::Enum a, Name b) \
 144      { \
 145        return Name(a) Op b; \
 146      } \
 147  \
 148      inline MOZ_CONSTEXPR mozilla::CastableTypedEnumResult<Name> \
 149      operator Op(Name::Enum a, Name::Enum b) \
 150      { \
 151        return Name(a) Op Name(b); \
 152      } \
 153  \
 154      inline Name& \
 155      operator Op##=(Name& a, Name::Enum b) \
 156      { \
 157        return a = a Op Name(b); \
 158     }
 159
 160 #  define MOZ_MAKE_ENUM_CLASS_OPS_EXTRA_NON_CXX11(Name) \
 161      MOZ_MAKE_ENUM_CLASS_BITWISE_BINOP_EXTRA_NON_CXX11(Name, |) \
 162      MOZ_MAKE_ENUM_CLASS_BITWISE_BINOP_EXTRA_NON_CXX11(Name, &) \
 163      MOZ_MAKE_ENUM_CLASS_BITWISE_BINOP_EXTRA_NON_CXX11(Name, ^) \
 164      inline MOZ_CONSTEXPR mozilla::CastableTypedEnumResult<Name> \
 165      operator~(Name::Enum a) \
 166      { \
 167        return ~(Name(a)); \
 168      }
 169 #endif
 170
 171 /**
 172  * MOZ_MAKE_ENUM_CLASS_BITWISE_OPERATORS generates standard bitwise operators
 173  * for the given enum type. Use this to enable using an enum type as bit-field.
 174  */
 175 #ifdef MOZ_HAVE_CXX11_STRONG_ENUMS
 176 #  define MOZ_MAKE_ENUM_CLASS_BITWISE_OPERATORS(Name) \
 177      MOZ_MAKE_ENUM_CLASS_OPS_IMPL(Name)
 178 #else
 179 #  define MOZ_MAKE_ENUM_CLASS_BITWISE_OPERATORS(Name) \
 180      MOZ_MAKE_ENUM_CLASS_OPS_IMPL(Name) \
 181      MOZ_MAKE_ENUM_CLASS_OPS_EXTRA_NON_CXX11(Name)
 182 #endif
 183
 184 #endif // mozilla_TypedEnumBits_h