1 /* 2 * Copyright (c) 2021 Huawei Device Co., Ltd. 3 * Licensed under the Apache License, Version 2.0 (the "License"); 4 * you may not use this file except in compliance with the License. 5 * You may obtain a copy of the License at 6 * 7 * http://www.apache.org/licenses/LICENSE-2.0 8 * 9 * Unless required by applicable law or agreed to in writing, software 10 * distributed under the License is distributed on an "AS IS" BASIS, 11 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 12 * See the License for the specific language governing permissions and 13 * limitations under the License. 14 */ 15 16 #ifndef PANDA_LIBPANDABASE_UTILS_ALIGNED_STORAGE_H_ 17 #define PANDA_LIBPANDABASE_UTILS_ALIGNED_STORAGE_H_ 18 19 #include "libpandabase/utils/bit_utils.h" 20 21 namespace panda { 22 23 /** 24 * Aligned storage with aligned elements. 25 * 26 * @tparam StructAlign Alignment of the structure 27 * @tparam ElementsAlign Alignment of the elements 28 * @tparam ElementsNum Number of elements in the structure, used for static checkers 29 */ 30 template <size_t StructAlign, size_t ElementsAlign, size_t ElementsNum> 31 struct alignas(StructAlign) AlignedStorage { 32 template <typename T> 33 using Aligned __attribute__((aligned(ElementsAlign))) = T; 34 35 static constexpr size_t STRUCT_ALIGN = StructAlign; 36 static constexpr size_t ELEMENTS_ALIGN = ElementsAlign; 37 static constexpr size_t ELEMENTS_NUM = ElementsNum; 38 GetSizeAlignedStorage39 static constexpr size_t GetSize() 40 { 41 return RoundUp(ElementsNum * ElementsAlign, StructAlign); 42 } 43 ConvertOffsetAlignedStorage44 static constexpr size_t ConvertOffset(size_t dst_align, size_t offset) 45 { 46 return (dst_align > ElementsAlign) ? (offset / (dst_align / ElementsAlign)) 47 : (offset / (ElementsAlign / dst_align)); 48 } 49 }; 50 51 } // namespace panda 52 53 #endif // PANDA_LIBPANDABASE_UTILS_ALIGNED_STORAGE_H_ 54