| /* |
| * Copyright (c) 2022, The OpenThread Authors. |
| * All rights reserved. |
| * |
| * Redistribution and use in source and binary forms, with or without |
| * modification, are permitted provided that the following conditions are met: |
| * 1. Redistributions of source code must retain the above copyright |
| * notice, this list of conditions and the following disclaimer. |
| * 2. Redistributions in binary form must reproduce the above copyright |
| * notice, this list of conditions and the following disclaimer in the |
| * documentation and/or other materials provided with the distribution. |
| * 3. Neither the name of the copyright holder nor the |
| * names of its contributors may be used to endorse or promote products |
| * derived from this software without specific prior written permission. |
| * |
| * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" |
| * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
| * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
| * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE |
| * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR |
| * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF |
| * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS |
| * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN |
| * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) |
| * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE |
| * POSSIBILITY OF SUCH DAMAGE. |
| */ |
| |
| /** |
| * @file |
| * This file includes definitions for serial number comparison similar to RFC-1982. |
| */ |
| |
| #ifndef SERIAL_NUMBER_HPP_ |
| #define SERIAL_NUMBER_HPP_ |
| |
| #include "openthread-core-config.h" |
| |
| #include <stdint.h> |
| |
| #include "common/numeric_limits.hpp" |
| #include "common/type_traits.hpp" |
| |
| namespace ot { |
| |
| class SerialNumber |
| { |
| public: |
| /** |
| * This static method indicates whether or not a first serial number is strictly less than a second serial number. |
| * |
| * The comparison takes into account the wrapping of serial number values (similar to RFC-1982). It is semantically |
| * equivalent to `aFirst < aSecond`. |
| * |
| * @tparam UintType The unsigned integer type. |
| * |
| * @param[in] aFirst The first serial number. |
| * @param[in] aSecond The second serial number. |
| * |
| * @retval TRUE If @p aFirst is less than @p aSecond. |
| * @retval FALSE If @p aFirst is not less than @p aSecond. |
| * |
| */ |
| template <typename UintType> static bool IsLess(UintType aFirst, UintType aSecond) |
| { |
| static_assert(TypeTraits::IsSame<UintType, uint8_t>::kValue || TypeTraits::IsSame<UintType, uint16_t>::kValue || |
| TypeTraits::IsSame<UintType, uint32_t>::kValue || |
| TypeTraits::IsSame<UintType, uint64_t>::kValue, |
| "UintType MUST be an 8, 16, 32, or 64 bit `uint` type"); |
| |
| static constexpr UintType kNegativeMask = (NumericLimits<UintType>::kMax >> 1) + 1; |
| |
| return ((aFirst - aSecond) & kNegativeMask) != 0; |
| } |
| |
| /** |
| * This static method indicates whether or not a first serial number is strictly greater than a second serial |
| * number. |
| * |
| * The comparison takes into account the wrapping of serial number values (similar to RFC-1982). It is semantically |
| * equivalent to `aFirst > aSecond`. |
| * |
| * @tparam UintType The unsigned integer type. |
| * |
| * @param[in] aFirst The first serial number. |
| * @param[in] aSecond The second serial number. |
| * |
| * @retval TRUE If @p aFirst is greater than @p aSecond. |
| * @retval FALSE If @p aFirst is not greater than @p aSecond. |
| * |
| */ |
| template <typename UintType> static bool IsGreater(UintType aFirst, UintType aSecond) |
| { |
| return IsLess(aSecond, aFirst); |
| } |
| }; |
| |
| } // namespace ot |
| |
| #endif // SERIAL_NUMBER_HPP_ |