1 /*
2 * Copyright 2021 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 FLATBUFFERS_DEFAULT_ALLOCATOR_H_
18 #define FLATBUFFERS_DEFAULT_ALLOCATOR_H_
19
20 #include "flatbuffers/allocator.h"
21 #include "flatbuffers/base.h"
22
23 namespace flatbuffers {
24
25 // DefaultAllocator uses new/delete to allocate memory regions
26 class DefaultAllocator : public Allocator {
27 public:
allocate(size_t size)28 uint8_t *allocate(size_t size) FLATBUFFERS_OVERRIDE {
29 return new uint8_t[size];
30 }
31
deallocate(uint8_t * p,size_t)32 void deallocate(uint8_t *p, size_t) FLATBUFFERS_OVERRIDE { delete[] p; }
33
dealloc(void * p,size_t)34 static void dealloc(void *p, size_t) { delete[] static_cast<uint8_t *>(p); }
35 };
36
37 // These functions allow for a null allocator to mean use the default allocator,
38 // as used by DetachedBuffer and vector_downward below.
39 // This is to avoid having a statically or dynamically allocated default
40 // allocator, or having to move it between the classes that may own it.
Allocate(Allocator * allocator,size_t size)41 inline uint8_t *Allocate(Allocator *allocator, size_t size) {
42 return allocator ? allocator->allocate(size)
43 : DefaultAllocator().allocate(size);
44 }
45
Deallocate(Allocator * allocator,uint8_t * p,size_t size)46 inline void Deallocate(Allocator *allocator, uint8_t *p, size_t size) {
47 if (allocator)
48 allocator->deallocate(p, size);
49 else
50 DefaultAllocator().deallocate(p, size);
51 }
52
ReallocateDownward(Allocator * allocator,uint8_t * old_p,size_t old_size,size_t new_size,size_t in_use_back,size_t in_use_front)53 inline uint8_t *ReallocateDownward(Allocator *allocator, uint8_t *old_p,
54 size_t old_size, size_t new_size,
55 size_t in_use_back, size_t in_use_front) {
56 return allocator ? allocator->reallocate_downward(old_p, old_size, new_size,
57 in_use_back, in_use_front)
58 : DefaultAllocator().reallocate_downward(
59 old_p, old_size, new_size, in_use_back, in_use_front);
60 }
61
62 } // namespace flatbuffers
63
64 #endif // FLATBUFFERS_DEFAULT_ALLOCATOR_H_