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 Clearable class for OpenThread objects.
32 */
33
34 #ifndef CLEARABLE_HPP_
35 #define CLEARABLE_HPP_
36
37 #include "openthread-core-config.h"
38
39 #include <string.h>
40
41 #include "common/type_traits.hpp"
42
43 namespace ot {
44
45 /**
46 * Clears (sets to zero) all bytes of a given object.
47 *
48 * @tparam ObjectType The object type.
49 *
50 * @param[in] aObject A reference to the object of type `ObjectType` to clear all its bytes.
51 *
52 */
ClearAllBytes(ObjectType & aObject)53 template <typename ObjectType> void ClearAllBytes(ObjectType &aObject)
54 {
55 static_assert(!TypeTraits::IsPointer<ObjectType>::kValue, "ObjectType must not be a pointer");
56
57 memset(reinterpret_cast<void *>(&aObject), 0, sizeof(ObjectType));
58 }
59
60 /**
61 * Defines a `Clearable` object which provides `Clear()` method.
62 *
63 * The `Clear` implementation simply sets all the bytes of a `Type` instance to zero.
64 *
65 * Users of this class should follow CRTP-style inheritance, i.e., the `Type` class itself should publicly inherit
66 * from `Clearable<Type>`.
67 *
68 */
69 template <typename Type> class Clearable
70 {
71 public:
Clear(void)72 void Clear(void) { ClearAllBytes<Type>(*static_cast<Type *>(this)); }
73 };
74
75 } // namespace ot
76
77 #endif // CLEARABLE_HPP_
78