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gerrit-public.fairphone.software / fp2-dev / platform / external / v8 / ad7c4bb32cb75428852721925b6423c21145bd5a / . / src / base / flags.h
blob: f3420ee536112f887b0cec648fb96a1e83170ca5 [file] [log] [blame]
Ben Murdochb8a8cc12014-11-26 15:28:44 +0000[diff] [blame]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 "src/base/compiler-specific.h"
9
10namespace v8 {
11namespace base {
12
13// The Flags class provides a type-safe way of storing OR-combinations of enum
14// values. The Flags<T, S> class is a template class, where T is an enum type,
15// and S is the underlying storage type (usually int).
16//
17// The traditional C++ approach for storing OR-combinations of enum values is to
18// use an int or unsigned int variable. The inconvenience with this approach is
19// that there's no type checking at all; any enum value can be OR'd with any
20// other enum value and passed on to a function that takes an int or unsigned
21// int.
22template <typename T, typename S = int>
23class Flags FINAL {
24 public:
25 typedef T flag_type;
26 typedef S mask_type;
27
28 Flags() : mask_(0) {}
29 Flags(flag_type flag) : mask_(flag) {} // NOLINT(runtime/explicit)
30 explicit Flags(mask_type mask) : mask_(mask) {}
31
32 Flags& operator&=(const Flags& flags) {
33 mask_ &= flags.mask_;
34 return *this;
35 }
36 Flags& operator|=(const Flags& flags) {
37 mask_ |= flags.mask_;
38 return *this;
39 }
40 Flags& operator^=(const Flags& flags) {
41 mask_ ^= flags.mask_;
42 return *this;
43 }
44
45 Flags operator&(const Flags& flags) const { return Flags(*this) &= flags; }
46 Flags operator|(const Flags& flags) const { return Flags(*this) |= flags; }
47 Flags operator^(const Flags& flags) const { return Flags(*this) ^= flags; }
48
49 Flags& operator&=(flag_type flag) { return operator&=(Flags(flag)); }
50 Flags& operator|=(flag_type flag) { return operator|=(Flags(flag)); }
51 Flags& operator^=(flag_type flag) { return operator^=(Flags(flag)); }
52
53 Flags operator&(flag_type flag) const { return operator&(Flags(flag)); }
54 Flags operator|(flag_type flag) const { return operator|(Flags(flag)); }
55 Flags operator^(flag_type flag) const { return operator^(Flags(flag)); }
56
57 Flags operator~() const { return Flags(~mask_); }
58
59 operator mask_type() const { return mask_; }
60 bool operator!() const { return !mask_; }
61
62 private:
63 mask_type mask_;
64};
65
66
67#define DEFINE_OPERATORS_FOR_FLAGS(Type) \
68 inline Type operator&(Type::flag_type lhs, \
69 Type::flag_type rhs)ALLOW_UNUSED WARN_UNUSED_RESULT; \
70 inline Type operator&(Type::flag_type lhs, Type::flag_type rhs) { \
71 return Type(lhs) & rhs; \
72 } \
73 inline Type operator&(Type::flag_type lhs, \
74 const Type& rhs)ALLOW_UNUSED WARN_UNUSED_RESULT; \
75 inline Type operator&(Type::flag_type lhs, const Type& rhs) { \
76 return rhs & lhs; \
77 } \
78 inline void operator&(Type::flag_type lhs, Type::mask_type rhs)ALLOW_UNUSED; \
79 inline void operator&(Type::flag_type lhs, Type::mask_type rhs) {} \
80 inline Type operator|(Type::flag_type lhs, Type::flag_type rhs) \
81 ALLOW_UNUSED WARN_UNUSED_RESULT; \
82 inline Type operator|(Type::flag_type lhs, Type::flag_type rhs) { \
83 return Type(lhs) | rhs; \
84 } \
85 inline Type operator|(Type::flag_type lhs, const Type& rhs) \
86 ALLOW_UNUSED WARN_UNUSED_RESULT; \
87 inline Type operator|(Type::flag_type lhs, const Type& rhs) { \
88 return rhs | lhs; \
89 } \
90 inline void operator|(Type::flag_type lhs, Type::mask_type rhs) \
91 ALLOW_UNUSED; \
92 inline void operator|(Type::flag_type lhs, Type::mask_type rhs) {} \
93 inline Type operator^(Type::flag_type lhs, Type::flag_type rhs) \
94 ALLOW_UNUSED WARN_UNUSED_RESULT; \
95 inline Type operator^(Type::flag_type lhs, Type::flag_type rhs) { \
96 return Type(lhs) ^ rhs; \
97 } inline Type operator^(Type::flag_type lhs, const Type& rhs) \
98 ALLOW_UNUSED WARN_UNUSED_RESULT; \
99 inline Type operator^(Type::flag_type lhs, const Type& rhs) { \
100 return rhs ^ lhs; \
101 } inline void operator^(Type::flag_type lhs, Type::mask_type rhs) \
102 ALLOW_UNUSED; \
103 inline void operator^(Type::flag_type lhs, Type::mask_type rhs) {}
104
105} // namespace base
106} // namespace v8
107
108#endif // V8_BASE_FLAGS_H_