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1 /*
2  * Copyright (c) 2021 Huawei Device Co., Ltd.
3  * Licensed under the Apache License, Version 2.0 (the "License");
4  * you may not use this file except in compliance with the License.
5  * You may obtain a copy of the License at
6  *
7  *     http://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,
11  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12  * See the License for the specific language governing permissions and
13  * limitations under the License.
14  */
15 
16 #ifndef ECMASCRIPT_MEM_FREE_OBJECT_LIST_H
17 #define ECMASCRIPT_MEM_FREE_OBJECT_LIST_H
18 
19 #include <cstddef>
20 
21 #include "ecmascript/mem/free_object_set.h"
22 #include "utils/span.h"
23 
24 namespace panda::ecmascript {
25 class FreeObjectList {
26 public:
27     FreeObjectList();
28     ~FreeObjectList();
29 
30     FreeObject *Allocate(size_t size);
31 
32     FreeObject *LookupSuitableFreeObject(size_t size);
33 
34     void Free(uintptr_t start, size_t size, bool isAdd = true);
35 
36     void Rebuild();
37 
38     bool AddSet(FreeObjectSet *set);
39 
40     void RemoveSet(FreeObjectSet *set);
41 
42     void Merge(FreeObjectList *list);
43 
44     template<class Callback>
45     void EnumerateSets(const Callback &cb) const;
46 
47     template<class Callback>
48     void EnumerateSets(SetType type, const Callback &cb) const;
49 
50     template<class Callback>
51     void EnumerateTopAndLastSets(const Callback &cb) const;
52 
53     NO_COPY_SEMANTIC(FreeObjectList);
54     NO_MOVE_SEMANTIC(FreeObjectList);
55 
GetFreeObjectSize()56     size_t GetFreeObjectSize() const
57     {
58         return available_;
59     }
GetWastedSize()60     size_t GetWastedSize() const
61     {
62         return wasted_;
63     }
DecrementWastedSize(size_t size)64     void DecrementWastedSize(size_t size)
65     {
66         wasted_ -= size;
67     }
IncrementWastedSize(size_t size)68     void IncrementWastedSize(size_t size)
69     {
70         wasted_ += size;
71     }
72 
NumberOfSets()73     static int NumberOfSets()
74     {
75         return NUMBER_OF_SETS;
76     }
77 
78 private:
79     static constexpr int NUMBER_OF_SETS = 39;
80     static constexpr size_t MIN_SIZE = 16;
81     static constexpr size_t SMALL_SET_MAX_SIZE = 256;
82     static constexpr size_t LARGE_SET_MAX_SIZE = 65536;
83     static constexpr size_t HUGE_SET_MAX_SIZE = 255 * 1024;
84     static constexpr int SMALL_SET_MAX_INDEX = 29;
85     static constexpr int NUMBER_OF_LAST_LARGE = NUMBER_OF_SETS - 2;
86     static constexpr int NUMBER_OF_LAST_HUGE = NUMBER_OF_SETS - 1;
87     static constexpr size_t INTERVAL_OFFSET = 3;
88     static constexpr size_t LOG2_OFFSET = 21;
89     static constexpr size_t MAX_BIT_OF_SIZET = sizeof(size_t) << INTERVAL_OFFSET;
90     const int smallSetOffsetIndex = 2;
91 
92     inline SetType SelectSetType(size_t size) const;
93 
94     inline void SetNoneEmptyBit(SetType type);
95     inline void ClearNoneEmptyBit(SetType type);
96     inline size_t CalcNextNoneEmptyIndex(SetType start);
97 
98     size_t available_ = 0;
99     size_t wasted_ = 0;
100     uint64_t noneEmptySetBitMap_;
101     Span<FreeObjectSet *> sets_ {};
102     Span<FreeObjectSet *> lastSets_ {};
103 };
104 }  // namespace panda::ecmascript
105 #endif  // ECMASCRIPT_MEM_FREE_OBJECT_LIST_H
106