1 /* 2 * Copyright (c) 2020, The OpenThread Authors. 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 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 * 3. Neither the name of the copyright holder nor the 13 * names of its contributors may be used to endorse or promote products 14 * derived from this software without specific prior written permission. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" 17 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE 20 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 21 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 22 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 23 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 24 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 25 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 26 * POSSIBILITY OF SUCH DAMAGE. 27 */ 28 29 /** 30 * @file 31 * This file includes definitions for Equatable class for OpenThread objects. 32 */ 33 34 #ifndef EQUATABLE_HPP_ 35 #define EQUATABLE_HPP_ 36 37 #include "openthread-core-config.h" 38 39 #include <string.h> 40 41 namespace ot { 42 43 /** 44 * Defines an overload of operator `!=`. 45 * 46 * The `!=` implementation uses an existing `==` overload provided by the `Type` class. 47 * 48 * Users of this class should follow CRTP-style inheritance, i.e., the `Type` class itself should publicly inherit 49 * from `Unequatable<Type>`. 50 */ 51 template <typename Type> class Unequatable 52 { 53 public: 54 /** 55 * Overloads operator `!=` to evaluate whether or not two instances of `Type` are equal. 56 * 57 * This is implemented in terms of an existing `==` overload provided by `Type` class itself. 58 * 59 * @param[in] aOther The other `Type` instance to compare with. 60 * 61 * @retval TRUE If the two `Type` instances are not equal. 62 * @retval FALSE If the two `Type` instances are equal. 63 */ operator !=(const Type & aOther) const64 bool operator!=(const Type &aOther) const { return !(*static_cast<const Type *>(this) == aOther); } 65 }; 66 67 /** 68 * Defines overloads of operators `==` and `!=`. 69 * 70 * The `==` implementation simply compares all the bytes of two `Type` instances to be equal (using `memcmp()`). 71 * 72 * Users of this class should follow CRTP-style inheritance, i.e., the `Type` class itself should publicly inherit 73 * from `Equatable<Type>`. 74 */ 75 template <typename Type> class Equatable : public Unequatable<Type> 76 { 77 public: 78 /** 79 * Overloads operator `==` to evaluate whether or not two instances of `Type` are equal. 80 * 81 * @param[in] aOther The other `Type` instance to compare with. 82 * 83 * @retval TRUE If the two `Type` instances are equal. 84 * @retval FALSE If the two `Type` instances are not equal. 85 */ operator ==(const Type & aOther) const86 bool operator==(const Type &aOther) const 87 { 88 return memcmp(static_cast<const Type *>(this), &aOther, sizeof(Type)) == 0; 89 } 90 }; 91 92 } // namespace ot 93 94 #endif // EQUATABLE_HPP_ 95