1 /* 2 * Copyright (C) 2013 Apple Inc. All rights reserved. 3 * 4 * Redistribution and use in source and binary forms, with or without 5 * modification, are permitted provided that the following conditions 6 * are met: 7 * 1. Redistributions of source code must retain the above copyright 8 * notice, this list of conditions and the following disclaimer. 9 * 2. Redistributions in binary form must reproduce the above copyright 10 * notice, this list of conditions and the following disclaimer in the 11 * documentation and/or other materials provided with the distribution. 12 * 13 * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY 14 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 15 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 16 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR 17 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, 18 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, 19 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR 20 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY 21 * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 22 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 23 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 24 */ 25 26 #ifndef WTF_EnumClass_h 27 #define WTF_EnumClass_h 28 29 #include "wtf/Compiler.h" 30 31 namespace WTF { 32 33 // How to define a type safe enum list using the ENUM_CLASS macros? 34 // =============================================================== 35 // To get an enum list like this: 36 // 37 // enum class MyEnums { 38 // Value1, 39 // Value2, 40 // ... 41 // ValueN 42 // }; 43 // 44 // ... write this: 45 // 46 // ENUM_CLASS(MyEnums) { 47 // Value1, 48 // Value2, 49 // ... 50 // ValueN 51 // } ENUM_CLASS_END(MyEnums); 52 // 53 // The ENUM_CLASS macros will use C++11's enum class if the compiler supports it. 54 // Otherwise, it will use the EnumClass template below. 55 56 #if COMPILER_SUPPORTS(CXX_STRONG_ENUMS) 57 58 #define ENUM_CLASS(__enumName) \ 59 enum class __enumName 60 61 #define ENUM_CLASS_END(__enumName) 62 63 #else // !COMPILER_SUPPORTS(CXX_STRONG_ENUMS) 64 65 // How to define a type safe enum list using the EnumClass template? 66 // ================================================================ 67 // Definition should be a struct that encapsulates an enum list. 68 // The enum list should be names Enums. 69 // 70 // Here's an example of how to define a type safe enum named MyEnum using 71 // the EnumClass template: 72 // 73 // struct MyEnumDefinition { 74 // enum Enums { 75 // ValueDefault, 76 // Value1, 77 // ... 78 // ValueN 79 // }; 80 // }; 81 // typedef EnumClass<MyEnumDefinition, MyEnumDefinition::ValueDefault> MyEnum; 82 // 83 // With that, you can now use MyEnum enum values as follow: 84 // 85 // MyEnum value1; // value1 is assigned MyEnum::ValueDefault by default. 86 // MyEnum value2 = MyEnum::Value1; // value2 is assigned MyEnum::Value1; 87 88 template <typename Definition> 89 class EnumClass : public Definition { 90 typedef enum Definition::Enums Value; 91 public: 92 ALWAYS_INLINE EnumClass() { } 93 ALWAYS_INLINE EnumClass(Value value) : m_value(value) { } 94 95 ALWAYS_INLINE Value value() const { return m_value; } 96 97 ALWAYS_INLINE bool operator==(const EnumClass other) { return m_value == other.m_value; } 98 ALWAYS_INLINE bool operator!=(const EnumClass other) { return m_value != other.m_value; } 99 ALWAYS_INLINE bool operator<(const EnumClass other) { return m_value < other.m_value; } 100 ALWAYS_INLINE bool operator<=(const EnumClass other) { return m_value <= other.m_value; } 101 ALWAYS_INLINE bool operator>(const EnumClass other) { return m_value > other.m_value; } 102 ALWAYS_INLINE bool operator>=(const EnumClass other) { return m_value >= other.m_value; } 103 104 ALWAYS_INLINE bool operator==(const Value value) { return m_value == value; } 105 ALWAYS_INLINE bool operator!=(const Value value) { return m_value != value; } 106 ALWAYS_INLINE bool operator<(const Value value) { return m_value < value; } 107 ALWAYS_INLINE bool operator<=(const Value value) { return m_value <= value; } 108 ALWAYS_INLINE bool operator>(const Value value) { return m_value > value; } 109 ALWAYS_INLINE bool operator>=(const Value value) { return m_value >= value; } 110 111 ALWAYS_INLINE operator Value() { return m_value; } 112 113 private: 114 Value m_value; 115 }; 116 117 #define ENUM_CLASS(__enumName) \ 118 struct __enumName ## Definition { \ 119 enum Enums 120 121 #define ENUM_CLASS_END(__enumName) \ 122 ; \ 123 }; \ 124 typedef EnumClass< __enumName ## Definition > __enumName 125 126 #endif // !COMPILER_SUPPORTS(CXX_STRONG_ENUMS) 127 128 } // namespace WTF 129 130 #if !COMPILER_SUPPORTS(CXX_STRONG_ENUMS) 131 using WTF::EnumClass; 132 #endif 133 134 #endif // WTF_EnumClass_h 135
