Line data Source code
1 : // Copyright 2014 the V8 project authors. All rights reserved.
2 : // Use of this source code is governed by a BSD-style license that can be
3 : // found in the LICENSE file.
4 :
5 : #ifndef V8_BASE_FLAGS_H_
6 : #define V8_BASE_FLAGS_H_
7 :
8 : #include <cstddef>
9 :
10 : #include "src/base/compiler-specific.h"
11 :
12 : namespace v8 {
13 : namespace base {
14 :
15 : // The Flags class provides a type-safe way of storing OR-combinations of enum
16 : // values. The Flags<T, S> class is a template class, where T is an enum type,
17 : // and S is the underlying storage type (usually int).
18 : //
19 : // The traditional C++ approach for storing OR-combinations of enum values is to
20 : // use an int or unsigned int variable. The inconvenience with this approach is
21 : // that there's no type checking at all; any enum value can be OR'd with any
22 : // other enum value and passed on to a function that takes an int or unsigned
23 : // int.
24 : template <typename T, typename S = int>
25 : class Flags final {
26 : public:
27 : typedef T flag_type;
28 : typedef S mask_type;
29 :
30 187303 : constexpr Flags() : mask_(0) {}
31 128526 : constexpr Flags(flag_type flag) // NOLINT(runtime/explicit)
32 34458437 : : mask_(static_cast<S>(flag)) {}
33 14912108 : constexpr explicit Flags(mask_type mask) : mask_(static_cast<S>(mask)) {}
34 :
35 : constexpr bool operator==(flag_type flag) const {
36 1890536 : return mask_ == static_cast<S>(flag);
37 : }
38 : constexpr bool operator!=(flag_type flag) const {
39 : return mask_ != static_cast<S>(flag);
40 : }
41 :
42 : Flags& operator&=(const Flags& flags) {
43 1952007362 : mask_ &= flags.mask_;
44 : return *this;
45 : }
46 : Flags& operator|=(const Flags& flags) {
47 14246160 : mask_ |= flags.mask_;
48 : return *this;
49 : }
50 : Flags& operator^=(const Flags& flags) {
51 75552 : mask_ ^= flags.mask_;
52 : return *this;
53 : }
54 :
55 : constexpr Flags operator&(const Flags& flags) const {
56 1256340725 : return Flags(*this) &= flags;
57 : }
58 : constexpr Flags operator|(const Flags& flags) const {
59 2713051 : return Flags(*this) |= flags;
60 : }
61 : constexpr Flags operator^(const Flags& flags) const {
62 : return Flags(*this) ^= flags;
63 : }
64 :
65 : Flags& operator&=(flag_type flag) { return operator&=(Flags(flag)); }
66 : Flags& operator|=(flag_type flag) { return operator|=(Flags(flag)); }
67 : Flags& operator^=(flag_type flag) { return operator^=(Flags(flag)); }
68 :
69 350303 : constexpr Flags operator&(flag_type flag) const {
70 350303 : return operator&(Flags(flag));
71 : }
72 : constexpr Flags operator|(flag_type flag) const {
73 : return operator|(Flags(flag));
74 : }
75 : constexpr Flags operator^(flag_type flag) const {
76 : return operator^(Flags(flag));
77 : }
78 :
79 1106840 : constexpr Flags operator~() const { return Flags(~mask_); }
80 :
81 4013512 : constexpr operator mask_type() const { return mask_; }
82 164591 : constexpr bool operator!() const { return !mask_; }
83 :
84 0 : friend size_t hash_value(const Flags& flags) { return flags.mask_; }
85 :
86 : private:
87 : mask_type mask_;
88 : };
89 :
90 : #define DEFINE_OPERATORS_FOR_FLAGS(Type) \
91 : inline Type operator&( \
92 : Type::flag_type lhs, \
93 : Type::flag_type rhs)ALLOW_UNUSED_TYPE V8_WARN_UNUSED_RESULT; \
94 : inline Type operator&(Type::flag_type lhs, Type::flag_type rhs) { \
95 : return Type(lhs) & rhs; \
96 : } \
97 : inline Type operator&( \
98 : Type::flag_type lhs, \
99 : const Type& rhs)ALLOW_UNUSED_TYPE V8_WARN_UNUSED_RESULT; \
100 : inline Type operator&(Type::flag_type lhs, const Type& rhs) { \
101 : return rhs & lhs; \
102 : } \
103 : inline void operator&(Type::flag_type lhs, \
104 : Type::mask_type rhs)ALLOW_UNUSED_TYPE; \
105 : inline void operator&(Type::flag_type lhs, Type::mask_type rhs) {} \
106 : inline Type operator|(Type::flag_type lhs, Type::flag_type rhs) \
107 : ALLOW_UNUSED_TYPE V8_WARN_UNUSED_RESULT; \
108 : inline Type operator|(Type::flag_type lhs, Type::flag_type rhs) { \
109 : return Type(lhs) | rhs; \
110 : } \
111 : inline Type operator|(Type::flag_type lhs, const Type& rhs) \
112 : ALLOW_UNUSED_TYPE V8_WARN_UNUSED_RESULT; \
113 : inline Type operator|(Type::flag_type lhs, const Type& rhs) { \
114 : return rhs | lhs; \
115 : } \
116 : inline void operator|(Type::flag_type lhs, Type::mask_type rhs) \
117 : ALLOW_UNUSED_TYPE; \
118 : inline void operator|(Type::flag_type lhs, Type::mask_type rhs) {} \
119 : inline Type operator^(Type::flag_type lhs, Type::flag_type rhs) \
120 : ALLOW_UNUSED_TYPE V8_WARN_UNUSED_RESULT; \
121 : inline Type operator^(Type::flag_type lhs, Type::flag_type rhs) { \
122 : return Type(lhs) ^ rhs; \
123 : } \
124 : inline Type operator^(Type::flag_type lhs, const Type& rhs) \
125 : ALLOW_UNUSED_TYPE V8_WARN_UNUSED_RESULT; \
126 : inline Type operator^(Type::flag_type lhs, const Type& rhs) { \
127 : return rhs ^ lhs; \
128 : } \
129 : inline void operator^(Type::flag_type lhs, Type::mask_type rhs) \
130 : ALLOW_UNUSED_TYPE; \
131 : inline void operator^(Type::flag_type lhs, Type::mask_type rhs) {} \
132 : inline Type operator~(Type::flag_type val)ALLOW_UNUSED_TYPE; \
133 : inline Type operator~(Type::flag_type val) { return ~Type(val); }
134 :
135 : } // namespace base
136 : } // namespace v8
137 :
138 : #endif // V8_BASE_FLAGS_H_
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