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: 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 Verhoeff checksum calculation and validation. 32 */ 33 34 #ifndef VERHOEFF_CHECKSUM_HPP_ 35 #define VERHOEFF_CHECKSUM_HPP_ 36 37 #include "openthread-core-config.h" 38 39 #if OPENTHREAD_CONFIG_VERHOEFF_CHECKSUM_ENABLE 40 41 #include <openthread/verhoeff_checksum.h> 42 43 #include "common/error.hpp" 44 45 namespace ot { 46 namespace Utils { 47 48 class VerhoeffChecksum 49 { 50 public: 51 /** 52 * Specifies the maximum length of decimal string input. 53 * 54 */ 55 static constexpr uint16_t kMaxStringLength = OT_VERHOEFF_CHECKSUM_MAX_STRING_LENGTH; 56 57 /** 58 * Calculates the Verhoeff checksum for a given decimal string. 59 * 60 * 61 * @param[in] a DecimalString The string containing decimal digits. 62 * @param[out] aChecksum Reference to a `char` to return the calculated checksum. 63 * 64 * @retval kErrorNone Successfully calculated the checksum, @p aChecksum is updated. 65 * @retval kErrorInvalidArgs The @p aDecimalString is not valid, i.e. it either contains chars other than 66 * ['0'-'9'], or is longer than `kMaxStringLength`. 67 * 68 */ 69 static Error Calculate(const char *aDecimalString, char &aChecksum); 70 71 /** 72 * Validates the Verhoeff checksum for a given decimal string. 73 * 74 * @param[in] aDecimalString The string containing decimal digits (last char is treated as checksum). 75 * 76 * @retval kErrorNone Successfully validated the checksum in @p aDecimalString. 77 * @retval kErrorFailed Checksum is not valid. 78 * @retval kErrorInvalidArgs The @p aDecimalString is not valid, i.e. it either contains chars other than 79 * ['0'-'9'], or is longer than `kMaxStringLength`. 80 * 81 */ 82 static Error Validate(const char *aDecimalString); 83 84 VerhoeffChecksum(void) = delete; 85 86 private: 87 static Error ComputeCode(const char *aDecimalString, uint8_t &aCode, bool aValidate); 88 static uint8_t Lookup(uint8_t aIndex, const uint8_t aCompressedArray[]); 89 static uint8_t Multiply(uint8_t aFirst, uint8_t aSecond); 90 static uint8_t Permute(uint8_t aPosition, uint8_t aValue); 91 static uint8_t InverseOf(uint8_t aValue); 92 }; 93 94 } // namespace Utils 95 } // namespace ot 96 97 #endif // OPENTHREAD_CONFIG_VERHOEFF_CHECKSUM_ENABLE 98 99 #endif // VERHOEFF_CHECKSUM_HPP_ 100
