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 numeric limits. 32 */ 33 34 #ifndef NUMERIC_LIMITS_HPP_ 35 #define NUMERIC_LIMITS_HPP_ 36 37 #include <stdint.h> 38 39 namespace ot { 40 41 static constexpr uint8_t kBitsPerByte = 8; ///< Number of bits in a byte. 42 43 /** 44 * Returns the bit-size (number of bits) of a given type or variable. 45 * 46 * @param[in] aItem The item (type or variable or expression) to get the bit-size of. 47 * 48 * @returns Number of bits of @p aItem. 49 */ 50 #define BitSizeOf(aItem) (sizeof(aItem) * kBitsPerByte) 51 52 /** 53 * Determines number of byes to represent a given number of bits. 54 * 55 * @param[in] aBitSize The bit-size (number of bits). 56 * 57 * @returns Number of bytes to represent @p aBitSize. 58 */ 59 #define BytesForBitSize(aBitSize) static_cast<uint8_t>(((aBitSize) + (kBitsPerByte - 1)) / kBitsPerByte) 60 61 /** 62 * Provides a way to query properties of arithmetic types. 63 * 64 * There are no members if `Type` is not a supported arithmetic type. 65 */ 66 template <typename Type> struct NumericLimits 67 { 68 }; 69 70 // Specialization for different integral types. 71 72 template <> struct NumericLimits<int8_t> 73 { 74 static constexpr int8_t kMin = INT8_MIN; 75 static constexpr int8_t kMax = INT8_MAX; 76 }; 77 78 template <> struct NumericLimits<int16_t> 79 { 80 static constexpr int16_t kMin = INT16_MIN; 81 static constexpr int16_t kMax = INT16_MAX; 82 }; 83 84 template <> struct NumericLimits<int32_t> 85 { 86 static constexpr int32_t kMin = INT32_MIN; 87 static constexpr int32_t kMax = INT32_MAX; 88 }; 89 90 template <> struct NumericLimits<int64_t> 91 { 92 static constexpr int64_t kMin = INT64_MIN; 93 static constexpr int64_t kMax = INT64_MAX; 94 }; 95 96 template <> struct NumericLimits<uint8_t> 97 { 98 static constexpr uint8_t kMin = 0; 99 static constexpr uint8_t kMax = UINT8_MAX; 100 }; 101 102 template <> struct NumericLimits<uint16_t> 103 { 104 static constexpr uint16_t kMin = 0; 105 static constexpr uint16_t kMax = UINT16_MAX; 106 }; 107 108 template <> struct NumericLimits<uint32_t> 109 { 110 static constexpr uint32_t kMin = 0; 111 static constexpr uint32_t kMax = UINT32_MAX; 112 }; 113 114 template <> struct NumericLimits<uint64_t> 115 { 116 static constexpr uint64_t kMin = 0; 117 static constexpr uint64_t kMax = UINT64_MAX; 118 }; 119 120 } // namespace ot 121 122 #endif // NUMERIC_LIMITS_HPP_ 123