1 /*
2  *  Copyright (c) 2024, 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:
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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
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27  */
28 
29 /**
30  * @file
31  * @brief
32  *   This file defines APIs for Verhoeff checksum calculation and validation.
33  */
34 
35 #ifndef OPENTHREAD_VERHOEFF_CHECKSUM_H_
36 #define OPENTHREAD_VERHOEFF_CHECKSUM_H_
37 
38 #include <openthread/error.h>
39 
40 #ifdef __cplusplus
41 extern "C" {
42 #endif
43 
44 /**
45  * @addtogroup api-verhoeff-checksum
46  *
47  * @brief
48  *   This module includes functions for Verhoeff checksum calculation and validation.
49  *
50  *   The functions in this module are available when `OPENTHREAD_CONFIG_VERHOEFF_CHECKSUM_ENABLE` is enabled.
51  *
52  * @{
53  *
54  */
55 
56 /**
57  * Specifies the maximum length of decimal string input in `otVerhoeffChecksum` functions.
58  *
59  */
60 #define OT_VERHOEFF_CHECKSUM_MAX_STRING_LENGTH 128
61 
62 /**
63  * Calculates the Verhoeff checksum for a given decimal string.
64  *
65  * Requires `OPENTHREAD_CONFIG_VERHOEFF_CHECKSUM_ENABLE`.
66  *
67  * @param[in]  aDecimalString   The string containing decimal digits.
68  * @param[out] aChecksum        Pointer to a `char` to return the calculated checksum.
69  *
70  * @retval OT_ERROR_NONE            Successfully calculated the checksum, @p aChecksum is updated.
71  * @retval OT_ERROR_INVALID_ARGS    The @p aDecimalString is not valid, i.e. it either contains chars other than
72  *                                  ['0'-'9'], or is longer than `OT_VERHOEFF_CHECKSUM_MAX_STRING_LENGTH`.
73  *
74  */
75 otError otVerhoeffChecksumCalculate(const char *aDecimalString, char *aChecksum);
76 
77 /**
78  * Validates the Verhoeff checksum for a given decimal string.
79  *
80  * Requires `OPENTHREAD_CONFIG_VERHOEFF_CHECKSUM_ENABLE`.
81  *
82  * @param[in] aDecimalString   The string containing decimal digits (last char is treated as checksum).
83  *
84  * @retval OT_ERROR_NONE            Successfully validated the checksum in @p aDecimalString.
85  * @retval OT_ERROR_FAILED          Checksum validation failed.
86  * @retval OT_ERROR_INVALID_ARGS    The @p aDecimalString is not valid, i.e. it either contains chars other than
87  *                                  ['0'-'9'], or is longer than `OT_VERHOEFF_CHECKSUM_MAX_STRING_LENGTH`.
88  *
89  */
90 otError otVerhoeffChecksumValidate(const char *aDecimalString);
91 
92 /**
93  * @}
94  *
95  */
96 
97 #ifdef __cplusplus
98 } // extern "C"
99 #endif
100 
101 #endif // OPENTHREAD_VERHOEFF_CHECKSUM_H_
102