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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 PANDA_VERIFICATION_UTIL_FLAGS_H_
17 #define PANDA_VERIFICATION_UTIL_FLAGS_H_
18 
19 #include "macros.h"
20 
21 #include <cstdint>
22 
23 namespace panda::verifier {
24 template <typename UInt, typename Enum, Enum...>
25 class FlagsForEnum;
26 
27 template <typename UInt, typename Enum, Enum Flag>
28 class FlagsForEnum<UInt, Enum, Flag> {
29 public:
30     class ConstBit {
31     public:
ConstBit(UInt bit_mask,const UInt & given_flags)32         ConstBit(UInt bit_mask, const UInt &given_flags) : mask {bit_mask}, flags {given_flags} {};
33         ConstBit() = delete;
34         ConstBit(const ConstBit &) = delete;
35         ConstBit(ConstBit &&) = delete;
36         ~ConstBit() = default;
37         operator bool() const
38         {
39             return (flags & mask) != 0;
40         }
41 
42     protected:
43         const UInt mask;
44         const UInt &flags;
45     };
46 
47     class Bit : public ConstBit {
48     public:
Bit(UInt bit_mask,UInt & given_flags)49         Bit(UInt bit_mask, UInt &given_flags) : ConstBit {bit_mask, given_flags} {};
50         ~Bit() = default;
51         Bit &operator=(bool b)
52         {
53             UInt &proper_flags = const_cast<UInt &>(ConstBit::flags);
54             if (b) {
55                 proper_flags |= ConstBit::mask;
56             } else {
57                 proper_flags &= ~ConstBit::mask;
58             }
59             return *this;
60         }
61     };
62 
63     template <typename Handler>
EnumerateFlags(Handler && handler)64     void EnumerateFlags(Handler &&handler) const
65     {
66         if (ConstBit {mask, flags_} == true) {
67             handler(Flag);
68         }
69     }
70 
71 #ifndef NDEBUG
72     ConstBit operator[](Enum f) const
73     {
74         ASSERT(f == Flag);
75         return {mask, flags_};
76     }
77 
78     Bit operator[](Enum f)
79     {
80         ASSERT(f == Flag);
81         return {mask, flags_};
82     }
83 #else
84     ConstBit operator[](Enum /* unused */) const
85     {
86         return {mask, flags_};
87     }
88 
89     Bit operator[](Enum /* unused */)
90     {
91         return {mask, flags_};
92     }
93 #endif
94 protected:
95     constexpr static UInt mask = static_cast<UInt>(1);
96     UInt flags_ {0};
97 };
98 
99 template <typename UInt, typename Enum, Enum Flag, Enum... Rest>
100 class FlagsForEnum<UInt, Enum, Flag, Rest...> : public FlagsForEnum<UInt, Enum, Rest...> {
101     using Base = FlagsForEnum<UInt, Enum, Rest...>;
102 
103 public:
104     typename Base::ConstBit operator[](Enum f) const
105     {
106         if (f == Flag) {
107             return {mask, Base::flags_};
108         }
109         return Base::operator[](f);
110     }
111 
112     typename Base::Bit operator[](Enum f)
113     {
114         if (f == Flag) {
115             return {mask, Base::flags_};
116         }
117         return Base::operator[](f);
118     }
119 
120     template <typename Handler>
EnumerateFlags(Handler && handler)121     void EnumerateFlags(Handler &&handler) const
122     {
123         if (typename Base::ConstBit {mask, Base::flags_} == true && !handler(Flag)) {
124             return;
125         }
126         Base::template EnumerateFlags<Handler>(std::move(handler));
127     }
128 
129 protected:
130     constexpr static UInt mask = Base::mask << static_cast<UInt>(1);
131     static_assert(mask != 0, "too many flags for UInt size");
132 };
133 }  // namespace panda::verifier
134 
135 #endif  // PANDA_VERIFICATION_UTIL_FLAGS_H_
136