1 /* 2 * Copyright 2014 Google Inc. All rights reserved. 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 #ifndef FRUIT_ARENA_ALLOCATOR_H 18 #define FRUIT_ARENA_ALLOCATOR_H 19 20 #include <fruit/impl/data_structures/memory_pool.h> 21 22 namespace fruit { 23 namespace impl { 24 25 /** 26 * An allocator that allocates memory in pages and only de-allocates memory on destruction. 27 * This is useful in code that needs many short-lived allocations. 28 * Each ArenaAllocator object should only be accessed by a single thread. 29 */ 30 template <typename T> 31 class ArenaAllocator { 32 private: 33 MemoryPool* pool; 34 35 template <class U> 36 friend class ArenaAllocator; 37 38 template <class U, class V> 39 friend bool operator==(const ArenaAllocator<U>& x, const ArenaAllocator<V>& y); 40 41 template <class U, class V> 42 friend bool operator!=(const ArenaAllocator<U>& x, const ArenaAllocator<V>& y); 43 44 public: 45 using value_type = T; 46 47 template <typename U> 48 struct rebind { 49 using other = ArenaAllocator<U>; 50 }; 51 52 /** 53 * Constructs an arena allocator using the specified memory pool. 54 * The MemoryPool object must outlive all allocators constructed with it and all allocated objects. 55 */ 56 explicit ArenaAllocator(MemoryPool& memory_pool); 57 58 template <typename U> 59 ArenaAllocator(const ArenaAllocator<U>&); // NOLINT(google-explicit-constructor) 60 61 T* allocate(std::size_t n); 62 void deallocate(T* p, std::size_t); 63 }; 64 65 template <class T, class U> 66 bool operator==(const ArenaAllocator<T>&, const ArenaAllocator<U>&); 67 68 template <class T, class U> 69 bool operator!=(const ArenaAllocator<T>&, const ArenaAllocator<U>&); 70 71 } // namespace impl 72 } // namespace fruit 73 74 #include <fruit/impl/data_structures/arena_allocator.defn.h> 75 76 #endif // FRUIT_ARENA_ALLOCATOR_H 77