| /* |
| * Licensed to the Apache Software Foundation (ASF) under one or more |
| * contributor license agreements. See the NOTICE file distributed with |
| * this work for additional information regarding copyright ownership. |
| * The ASF licenses this file to You under the Apache License, Version 2.0 |
| * (the "License"); you may not use this file except in compliance with |
| * the License. You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| #ifndef __STRINGID_MAKER_H__ |
| #define __STRINGID_MAKER_H__ |
| |
| #include <atomic> |
| #include <cstdint> |
| #include <string> |
| #include <cstddef> |
| |
| namespace rocketmq { |
| |
| class StringIdMaker { |
| private: |
| StringIdMaker(); |
| ~StringIdMaker(); |
| |
| public: |
| static StringIdMaker& getInstance() { |
| // After c++11, the initialization occurs exactly once |
| static StringIdMaker singleton_; |
| return singleton_; |
| } |
| |
| /* ID format: |
| * ip: 4 bytes |
| * pid: 2 bytes |
| * random: 4 bytes |
| * time: 4 bytes |
| * auto num: 2 bytes |
| */ |
| std::string createUniqID(); |
| |
| private: |
| void setStartTime(uint64_t millis); |
| |
| static uint32_t getIP(); |
| static void hexdump(unsigned char* buffer, char* out_buff, std::size_t index); |
| |
| private: |
| uint64_t mStartTime; |
| uint64_t mNextStartTime; |
| std::atomic<uint16_t> mCounter; |
| |
| char kFixString[21]; |
| |
| static const char sHexAlphabet[16]; |
| }; |
| |
| } // namespace rocketmq |
| #endif |