2 * Copyright 2016 Facebook, Inc.
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
8 * http://www.apache.org/licenses/LICENSE-2.0
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.
18 ////////////////////////////////////////////////////////////////////////////////
19 /// Disclaimer: This is intended only as a partial stand-in for
20 /// std::pmr::memory_resource (C++17) as needed for developing a
22 ////////////////////////////////////////////////////////////////////////////////
29 class memory_resource {
31 virtual ~memory_resource() = default;
32 virtual void* allocate(
34 const size_t alignment = alignof(std::max_align_t)) = 0;
35 virtual void deallocate(
38 const size_t alignment = alignof(std::max_align_t)) = 0;
41 memory_resource* get_default_resource();
42 void set_default_resource(memory_resource*);
43 memory_resource* new_delete_resource();
45 ////////////////////////////////////////////////////////////////////////////////
47 ////////////////////////////////////////////////////////////////////////////////
48 #include <folly/experimental/hazptr/debug.h>
50 inline memory_resource** default_mr_ptr() {
51 static memory_resource* default_mr = new_delete_resource();
52 DEBUG_PRINT(&default_mr << " " << default_mr);
56 inline memory_resource* get_default_resource() {
58 return *default_mr_ptr();
61 inline void set_default_resource(memory_resource* mr) {
63 *default_mr_ptr() = mr;
66 inline memory_resource* new_delete_resource() {
67 class new_delete : public memory_resource {
71 const size_t alignment = alignof(std::max_align_t)) {
73 void* p = static_cast<void*>(new char[bytes]);
74 DEBUG_PRINT(this << " " << p << " " << bytes);
80 const size_t alignment = alignof(std::max_align_t)) {
83 DEBUG_PRINT(p << " " << bytes);
84 delete[] static_cast<char*>(p);
91 } // namespace folly {
92 } // namespace hazptr {