| /* |
| * Copyright (C) 2017 The Android Open Source Project |
| * |
| * Licensed 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 SRC_TRACING_CORE_ID_ALLOCATOR_H_ |
| #define SRC_TRACING_CORE_ID_ALLOCATOR_H_ |
| |
| #include <stdint.h> |
| |
| #include <type_traits> |
| #include <vector> |
| |
| namespace perfetto { |
| |
| // Handles assigment of IDs (int types) from a fixed-size pool. |
| // Zero is not considered a valid ID. |
| // The base class takes always a uint32_t and the derived class casts and checks |
| // bounds at compile time. This is to avoid bloating code with different |
| // instances of the main class for each size. |
| class IdAllocatorGeneric { |
| public: |
| // |max_id| is inclusive. |
| explicit IdAllocatorGeneric(uint32_t max_id); |
| ~IdAllocatorGeneric(); |
| |
| // Returns an ID in the range [1, max_id] or 0 if no more ids are available. |
| uint32_t AllocateGeneric(); |
| void FreeGeneric(uint32_t); |
| |
| bool IsEmpty() const; |
| |
| private: |
| IdAllocatorGeneric(const IdAllocatorGeneric&) = delete; |
| IdAllocatorGeneric& operator=(const IdAllocatorGeneric&) = delete; |
| |
| const uint32_t max_id_; |
| uint32_t last_id_ = 0; |
| std::vector<bool> ids_; |
| }; |
| |
| template <typename T = uint32_t> |
| class IdAllocator : public IdAllocatorGeneric { |
| public: |
| explicit IdAllocator(T end) : IdAllocatorGeneric(end) { |
| static_assert(std::is_integral<T>::value && std::is_unsigned<T>::value, |
| "T must be an unsigned integer"); |
| static_assert(sizeof(T) <= sizeof(uint32_t), "T is too big"); |
| } |
| |
| T Allocate() { return static_cast<T>(AllocateGeneric()); } |
| void Free(T id) { FreeGeneric(id); } |
| }; |
| |
| } // namespace perfetto |
| |
| #endif // SRC_TRACING_CORE_ID_ALLOCATOR_H_ |