1 // Copyright 2024 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 "pw_allocator/allocator.h" 17 #include "pw_allocator/config.h" 18 #include "pw_status/status_with_size.h" 19 20 #if __has_include(<memory_resource>) 21 #include <memory_resource> 22 namespace pw { 23 namespace pmr = ::std::pmr; 24 } // namespace pw 25 26 #elif __has_include(<experimental/memory_resource>) 27 #include <experimental/memory_resource> 28 namespace pw { 29 namespace pmr = ::std::experimental::pmr; 30 } // namespace pw 31 32 #else 33 #error "<memory_resource> is required to use this header!" 34 #endif // __has_include(<memory_resource>) 35 36 namespace pw::allocator { 37 38 // Forward declaration 39 class PmrAllocator; 40 41 namespace internal { 42 43 /// Implementation of C++'s abstract memory resource interface that uses an 44 /// Allocator. 45 /// 46 /// NOTE! This class aborts if allocation fails. 47 /// 48 /// See also https://en.cppreference.com/w/cpp/memory/memory_resource. 49 class MemoryResource final : public pw::pmr::memory_resource { 50 public: 51 constexpr MemoryResource() = default; 52 allocator()53 Allocator& allocator() { return *allocator_; } 54 55 private: 56 friend class ::pw::allocator::PmrAllocator; set_allocator(Allocator & allocator)57 void set_allocator(Allocator& allocator) { allocator_ = &allocator; } 58 59 void* do_allocate(size_t bytes, size_t alignment) override; 60 void do_deallocate(void* p, size_t bytes, size_t alignment) override; 61 bool do_is_equal( 62 const pw::pmr::memory_resource& other) const noexcept override; 63 64 Allocator* allocator_ = nullptr; 65 }; 66 67 } // namespace internal 68 69 /// Implementation of C++'s abstract polymorphic allocator interface that uses 70 /// a pw::Allocator. 71 /// 72 /// Note that despite is name, this is NOT a pw::Allocator itself. Instead, it 73 /// can be used in `pw::pmr` containers, such as `pw::pmr::vector`. 74 /// 75 /// See also https://en.cppreference.com/w/cpp/memory/polymorphic_allocator. 76 class PmrAllocator final : public pw::pmr::polymorphic_allocator<std::byte> { 77 public: 78 using Base = pw::pmr::polymorphic_allocator<std::byte>; 79 PmrAllocator(Allocator & allocator)80 explicit PmrAllocator(Allocator& allocator) : Base(&memory_resource_) { 81 memory_resource_.set_allocator(allocator); 82 } 83 allocator()84 Allocator& allocator() { return memory_resource_.allocator(); } 85 86 private: 87 internal::MemoryResource memory_resource_; 88 }; 89 90 } // namespace pw::allocator 91