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 10450101 : Flags() : mask_(0) {}
31 335847 : Flags(flag_type flag) // NOLINT(runtime/explicit)
32 10355539 : : mask_(static_cast<S>(flag)) {}
33 4821249 : explicit Flags(mask_type mask) : mask_(static_cast<S>(mask)) {}
34 :
35 : bool operator==(flag_type flag) const {
36 1059934 : return mask_ == static_cast<S>(flag);
37 : }
38 : bool operator!=(flag_type flag) const {
39 : return mask_ != static_cast<S>(flag);
40 : }
41 :
42 : Flags& operator&=(const Flags& flags) {
43 6284720491 : mask_ &= flags.mask_;
44 : return *this;
45 : }
46 : Flags& operator|=(const Flags& flags) {
47 54789826 : mask_ |= flags.mask_;
48 : return *this;
49 : }
50 : Flags& operator^=(const Flags& flags) {
51 : mask_ ^= flags.mask_;
52 : return *this;
53 : }
54 :
55 5608655358 : Flags operator&(const Flags& flags) const { return Flags(*this) &= flags; }
56 2765653 : Flags operator|(const Flags& flags) const { return Flags(*this) |= flags; }
57 : Flags operator^(const Flags& flags) const { return Flags(*this) ^= flags; }
58 :
59 : Flags& operator&=(flag_type flag) { return operator&=(Flags(flag)); }
60 : Flags& operator|=(flag_type flag) { return operator|=(Flags(flag)); }
61 : Flags& operator^=(flag_type flag) { return operator^=(Flags(flag)); }
62 :
63 1619686 : Flags operator&(flag_type flag) const { return operator&(Flags(flag)); }
64 : Flags operator|(flag_type flag) const { return operator|(Flags(flag)); }
65 : Flags operator^(flag_type flag) const { return operator^(Flags(flag)); }
66 :
67 649952 : Flags operator~() const { return Flags(~mask_); }
68 :
69 4371119774 : operator mask_type() const { return mask_; }
70 1937884 : bool operator!() const { return !mask_; }
71 :
72 150914 : friend size_t hash_value(const Flags& flags) { return flags.mask_; }
73 :
74 : private:
75 : mask_type mask_;
76 : };
77 :
78 :
79 : #define DEFINE_OPERATORS_FOR_FLAGS(Type) \
80 : inline Type operator&( \
81 : Type::flag_type lhs, \
82 : Type::flag_type rhs)ALLOW_UNUSED_TYPE WARN_UNUSED_RESULT; \
83 : inline Type operator&(Type::flag_type lhs, Type::flag_type rhs) { \
84 : return Type(lhs) & rhs; \
85 : } \
86 : inline Type operator&(Type::flag_type lhs, \
87 : const Type& rhs)ALLOW_UNUSED_TYPE WARN_UNUSED_RESULT; \
88 : inline Type operator&(Type::flag_type lhs, const Type& rhs) { \
89 : return rhs & lhs; \
90 : } \
91 : inline void operator&(Type::flag_type lhs, \
92 : Type::mask_type rhs)ALLOW_UNUSED_TYPE; \
93 : inline void operator&(Type::flag_type lhs, Type::mask_type rhs) {} \
94 : inline Type operator|(Type::flag_type lhs, Type::flag_type rhs) \
95 : ALLOW_UNUSED_TYPE WARN_UNUSED_RESULT; \
96 : inline Type operator|(Type::flag_type lhs, Type::flag_type rhs) { \
97 : return Type(lhs) | rhs; \
98 : } \
99 : inline Type operator|(Type::flag_type lhs, const Type& rhs) \
100 : ALLOW_UNUSED_TYPE WARN_UNUSED_RESULT; \
101 : inline Type operator|(Type::flag_type lhs, const Type& rhs) { \
102 : return rhs | lhs; \
103 : } \
104 : inline void operator|(Type::flag_type lhs, Type::mask_type rhs) \
105 : ALLOW_UNUSED_TYPE; \
106 : inline void operator|(Type::flag_type lhs, Type::mask_type rhs) {} \
107 : inline Type operator^(Type::flag_type lhs, Type::flag_type rhs) \
108 : ALLOW_UNUSED_TYPE WARN_UNUSED_RESULT; \
109 : inline Type operator^(Type::flag_type lhs, Type::flag_type rhs) { \
110 : return Type(lhs) ^ rhs; \
111 : } inline Type \
112 : operator^(Type::flag_type lhs, const Type& rhs) \
113 : ALLOW_UNUSED_TYPE WARN_UNUSED_RESULT; \
114 : inline Type operator^(Type::flag_type lhs, const Type& rhs) { \
115 : return rhs ^ lhs; \
116 : } inline void \
117 : operator^(Type::flag_type lhs, Type::mask_type rhs) ALLOW_UNUSED_TYPE; \
118 : inline void operator^(Type::flag_type lhs, Type::mask_type rhs) { \
119 : } inline Type \
120 : operator~(Type::flag_type val)ALLOW_UNUSED_TYPE; \
121 : inline Type operator~(Type::flag_type val) { return ~Type(val); }
122 :
123 : } // namespace base
124 : } // namespace v8
125 :
126 : #endif // V8_BASE_FLAGS_H_
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