1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
|
// Copyright 2014 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef V8_BASE_FLAGS_H_
#define V8_BASE_FLAGS_H_
#include <cstddef>
#include "src/base/compiler-specific.h"
namespace v8 {
namespace base {
// The Flags class provides a type-safe way of storing OR-combinations of enum
// values. The Flags<T, S> class is a template class, where T is an enum type,
// and S is the underlying storage type (usually int).
//
// The traditional C++ approach for storing OR-combinations of enum values is to
// use an int or unsigned int variable. The inconvenience with this approach is
// that there's no type checking at all; any enum value can be OR'd with any
// other enum value and passed on to a function that takes an int or unsigned
// int.
template <typename T, typename S = int>
class Flags final {
public:
using flag_type = T;
using mask_type = S;
constexpr Flags() : mask_(0) {}
constexpr Flags(flag_type flag) // NOLINT(runtime/explicit)
: mask_(static_cast<S>(flag)) {}
constexpr explicit Flags(mask_type mask) : mask_(static_cast<S>(mask)) {}
constexpr bool operator==(flag_type flag) const {
return mask_ == static_cast<S>(flag);
}
constexpr bool operator!=(flag_type flag) const {
return mask_ != static_cast<S>(flag);
}
Flags& operator&=(const Flags& flags) {
mask_ &= flags.mask_;
return *this;
}
Flags& operator|=(const Flags& flags) {
mask_ |= flags.mask_;
return *this;
}
Flags& operator^=(const Flags& flags) {
mask_ ^= flags.mask_;
return *this;
}
constexpr Flags operator&(const Flags& flags) const {
return Flags(mask_ & flags.mask_);
}
constexpr Flags operator|(const Flags& flags) const {
return Flags(mask_ | flags.mask_);
}
constexpr Flags operator^(const Flags& flags) const {
return Flags(mask_ ^ flags.mask_);
}
Flags& operator&=(flag_type flag) { return operator&=(Flags(flag)); }
Flags& operator|=(flag_type flag) { return operator|=(Flags(flag)); }
Flags& operator^=(flag_type flag) { return operator^=(Flags(flag)); }
constexpr Flags operator&(flag_type flag) const {
return operator&(Flags(flag));
}
constexpr Flags operator|(flag_type flag) const {
return operator|(Flags(flag));
}
constexpr Flags operator^(flag_type flag) const {
return operator^(Flags(flag));
}
constexpr Flags operator~() const { return Flags(~mask_); }
constexpr operator mask_type() const { return mask_; }
constexpr bool operator!() const { return !mask_; }
Flags without(flag_type flag) { return *this & (~Flags(flag)); }
friend size_t hash_value(const Flags& flags) { return flags.mask_; }
private:
mask_type mask_;
};
#define DEFINE_OPERATORS_FOR_FLAGS(Type) \
inline Type operator&( \
Type::flag_type lhs, \
Type::flag_type rhs)ALLOW_UNUSED_TYPE V8_WARN_UNUSED_RESULT; \
inline Type operator&(Type::flag_type lhs, Type::flag_type rhs) { \
return Type(lhs) & rhs; \
} \
inline Type operator&( \
Type::flag_type lhs, \
const Type& rhs)ALLOW_UNUSED_TYPE V8_WARN_UNUSED_RESULT; \
inline Type operator&(Type::flag_type lhs, const Type& rhs) { \
return rhs & lhs; \
} \
inline void operator&(Type::flag_type lhs, \
Type::mask_type rhs)ALLOW_UNUSED_TYPE; \
inline void operator&(Type::flag_type lhs, Type::mask_type rhs) {} \
inline Type operator|(Type::flag_type lhs, Type::flag_type rhs) \
ALLOW_UNUSED_TYPE V8_WARN_UNUSED_RESULT; \
inline Type operator|(Type::flag_type lhs, Type::flag_type rhs) { \
return Type(lhs) | rhs; \
} \
inline Type operator|(Type::flag_type lhs, const Type& rhs) \
ALLOW_UNUSED_TYPE V8_WARN_UNUSED_RESULT; \
inline Type operator|(Type::flag_type lhs, const Type& rhs) { \
return rhs | lhs; \
} \
inline void operator|(Type::flag_type lhs, Type::mask_type rhs) \
ALLOW_UNUSED_TYPE; \
inline void operator|(Type::flag_type lhs, Type::mask_type rhs) {} \
inline Type operator^(Type::flag_type lhs, Type::flag_type rhs) \
ALLOW_UNUSED_TYPE V8_WARN_UNUSED_RESULT; \
inline Type operator^(Type::flag_type lhs, Type::flag_type rhs) { \
return Type(lhs) ^ rhs; \
} \
inline Type operator^(Type::flag_type lhs, const Type& rhs) \
ALLOW_UNUSED_TYPE V8_WARN_UNUSED_RESULT; \
inline Type operator^(Type::flag_type lhs, const Type& rhs) { \
return rhs ^ lhs; \
} \
inline void operator^(Type::flag_type lhs, Type::mask_type rhs) \
ALLOW_UNUSED_TYPE; \
inline void operator^(Type::flag_type lhs, Type::mask_type rhs) {} \
inline Type operator~(Type::flag_type val)ALLOW_UNUSED_TYPE; \
inline Type operator~(Type::flag_type val) { return ~Type(val); }
} // namespace base
} // namespace v8
#endif // V8_BASE_FLAGS_H_
|
