1 //===----------------------------------------------------------------------===// 2 // 3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4 // See https://llvm.org/LICENSE.txt for license information. 5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6 // 7 //===----------------------------------------------------------------------===// 8 9 10 // Assumption: minValue < maxValue 11 // Assumption: minValue <= rhs <= maxValue 12 // Assumption: minValue <= lhs <= maxValue 13 // Assumption: minValue >= 0 14 template <typename T, T minValue, T maxValue> euclidian_addition(T rhs,T lhs)15constexpr T euclidian_addition(T rhs, T lhs) { 16 const T modulus = maxValue - minValue + 1; 17 T ret = rhs + lhs; 18 if (ret > maxValue) 19 ret -= modulus; 20 return ret; 21 } 22 23 // Assumption: minValue < maxValue 24 // Assumption: minValue <= rhs <= maxValue 25 // Assumption: minValue <= lhs <= maxValue 26 // Assumption: minValue >= 0 27 template <typename T, T minValue, T maxValue> euclidian_subtraction(T lhs,T rhs)28constexpr T euclidian_subtraction(T lhs, T rhs) { 29 const T modulus = maxValue - minValue + 1; 30 T ret = lhs - rhs; 31 if (ret < minValue) 32 ret += modulus; 33 if (ret > maxValue) // this can happen if T is unsigned 34 ret += modulus; 35 return ret; 36 } 37