1 /* 2 * Copyright (c) 2025 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 COMMON_INTERFACES_OBJECTS_STRING_SLICED_STRING_H 17 #define COMMON_INTERFACES_OBJECTS_STRING_SLICED_STRING_H 18 19 #include "common_interfaces/objects/string/base_string_declare.h" 20 21 namespace common { 22 /* 23 +-----------------------------+ <-- offset 0 24 | BaseObject fields | 25 +-----------------------------+ 26 | LengthAndFlags (uint32_t) | 27 +-----------------------------+ 28 | RawHashcode (uint32_t) | 29 +-----------------------------+ <-- offset = BaseString::SIZE 30 | Parent (BaseString *) | <-- PARENT_OFFSET 31 +-----------------------------+ 32 | StartIndexAndFlags (uint32_t) | <-- STARTINDEX_AND_FLAGS_OFFSET 33 +-----------------------------+ <-- SIZE 34 */ 35 /* 36 +-------------------------------+ 37 | StartIndexAndFlags (uint32_t) | 38 +-------------------------------+ 39 Bit layout: 40 [0] : HasBackingStoreBit (1 bit) 41 [1] : ReserveBit (1 bit) 42 [2 - 31] : StartIndexBits (30 bits) 43 */ 44 // The substrings of another string use SlicedString to describe. 45 class SlicedString : public BaseString { 46 public: 47 BASE_CAST_CHECK(SlicedString, IsSlicedString); 48 NO_MOVE_SEMANTIC_CC(SlicedString); 49 NO_COPY_SEMANTIC_CC(SlicedString); 50 static constexpr uint32_t MIN_SLICED_STRING_LENGTH = 13; 51 static constexpr size_t PARENT_OFFSET = BaseString::SIZE; 52 static constexpr uint32_t START_INDEX_BITS_NUM = 30U; 53 using HasBackingStoreBit = BitField<bool, 0>; // 1 54 using ReserveBit = HasBackingStoreBit::NextFlag; // 1 55 using StartIndexBits = ReserveBit::NextField<uint32_t, START_INDEX_BITS_NUM>; // 30 56 static_assert(StartIndexBits::START_BIT + StartIndexBits::SIZE == sizeof(uint32_t) * BITS_PER_BYTE, 57 "StartIndexBits does not match the field size"); 58 static_assert(StartIndexBits::SIZE == LengthBits::SIZE, "The size of startIndex should be same with Length"); 59 60 POINTER_FIELD(Parent, PARENT_OFFSET, STARTINDEX_AND_FLAGS_OFFSET); 61 PRIMITIVE_FIELD(StartIndexAndFlags, uint32_t, STARTINDEX_AND_FLAGS_OFFSET, SIZE); 62 63 uint32_t GetStartIndex() const; 64 65 void SetStartIndex(uint32_t startIndex); 66 67 bool GetHasBackingStore() const; 68 69 void SetHasBackingStore(bool hasBackingStore); 70 71 // Minimum length for a sliced string 72 template <bool verify = true, typename ReadBarrier> 73 uint16_t Get(ReadBarrier &&readBarrier, int32_t index) const; 74 }; 75 } 76 #endif //COMMON_INTERFACES_OBJECTS_STRING_SLICED_STRING_H