| 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 |  |