1 // Copyright 2023 The Pigweed Authors 2 // 3 // Licensed under the Apache License, Version 2.0 (the "License"); you may not 4 // use this file except in compliance with the License. You may obtain a copy of 5 // the License at 6 // 7 // https://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, WITHOUT 11 // WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the 12 // License for the specific language governing permissions and limitations under 13 // the License. 14 #pragma once 15 16 #include <cstddef> 17 18 #include "pw_allocator/allocator.h" 19 #include "pw_allocator/layout.h" 20 #include "pw_result/result.h" 21 #include "pw_status/status.h" 22 23 namespace pw::allocator { 24 25 /// This class simply dispatches between a primary and secondary allocator. Any 26 /// attempt to allocate memory will first be handled by the primary allocator. 27 /// If it cannot allocate memory, e.g. because it is out of memory, the 28 /// secondary alloator will try to allocate memory instead. 29 class FallbackAllocator : public Allocator { 30 public: 31 /// Constructor. 32 /// 33 /// @param[in] primary Allocator tried first. Must implement `Query`. 34 /// @param[in] secondary Allocator tried if `primary` fails a request. 35 FallbackAllocator(Allocator& primary, Allocator& secondary); 36 37 private: 38 /// @copydoc Allocator::Allocate 39 void* DoAllocate(Layout layout) override; 40 41 /// @copydoc Allocator::Deallocate 42 void DoDeallocate(void* ptr) override; 43 44 /// @copydoc Allocator::Deallocate 45 void DoDeallocate(void* ptr, Layout) override; 46 47 /// @copydoc Allocator::Resize 48 bool DoResize(void* ptr, size_t new_size) override; 49 50 /// @copydoc Allocator::GetAllocated 51 size_t DoGetAllocated() const override; 52 53 /// @copydoc Deallocator::GetInfo 54 Result<Layout> DoGetInfo(InfoType info_type, const void* ptr) const override; 55 56 Allocator& primary_; 57 Allocator& secondary_; 58 }; 59 60 } // namespace pw::allocator 61