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Flags.h
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1 //===-- Flags.h -------------------------------------------------*- C++ -*-===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 
9 #ifndef LLDB_UTILITY_FLAGS_H
10 #define LLDB_UTILITY_FLAGS_H
11 
12 #include <cstddef>
13 #include <cstdint>
14 
15 namespace lldb_private {
16 
17 /// \class Flags Flags.h "lldb/Utility/Flags.h"
18 /// A class to manage flags.
19 ///
20 /// The Flags class managed flag bits and allows testing and modification of
21 /// individual or multiple flag bits.
22 class Flags {
23 public:
24  /// The value type for flags is a 32 bit unsigned integer type.
26 
27  /// Construct with initial flag bit values.
28  ///
29  /// Constructs this object with \a mask as the initial value for all of the
30  /// flags.
31  ///
32  /// \param[in] mask
33  /// The initial value for all flags.
34  Flags(ValueType flags = 0) : m_flags(flags) {}
35 
36  /// Copy constructor.
37  ///
38  /// Construct and copy the flags from \a rhs.
39  ///
40  /// \param[in] rhs
41  /// A const Flags object reference to copy.
42  Flags(const Flags &rhs) : m_flags(rhs.m_flags) {}
43 
44  /// Destructor.
45  ~Flags() {}
46 
47  /// Get accessor for all flags.
48  ///
49  /// \return
50  /// Returns all of the flags as a Flags::ValueType.
51  ValueType Get() const { return m_flags; }
52 
53  /// Return the number of flags that can be represented in this object.
54  ///
55  /// \return
56  /// The maximum number bits in this flag object.
57  size_t GetBitSize() const { return sizeof(ValueType) * 8; }
58 
59  /// Set accessor for all flags.
60  ///
61  /// \param[in] flags
62  /// The bits with which to replace all of the current flags.
63  void Reset(ValueType flags) { m_flags = flags; }
64 
65  /// Clear one or more flags.
66  ///
67  /// \param[in] mask
68  /// A bitfield containing one or more flags.
69  ///
70  /// \return
71  /// The new flags after clearing all bits from \a mask.
72  ValueType Clear(ValueType mask = ~(ValueType)0) {
73  m_flags &= ~mask;
74  return m_flags;
75  }
76 
77  /// Set one or more flags by logical OR'ing \a mask with the current flags.
78  ///
79  /// \param[in] mask
80  /// A bitfield containing one or more flags.
81  ///
82  /// \return
83  /// The new flags after setting all bits from \a mask.
84  ValueType Set(ValueType mask) {
85  m_flags |= mask;
86  return m_flags;
87  }
88 
89  /// Test if all bits in \a mask are 1 in the current flags
90  ///
91  /// \return
92  /// \b true if all flags in \a mask are 1, \b false
93  /// otherwise.
94  bool AllSet(ValueType mask) const { return (m_flags & mask) == mask; }
95 
96  /// Test one or more flags.
97  ///
98  /// \return
99  /// \b true if any flags in \a mask are 1, \b false
100  /// otherwise.
101  bool AnySet(ValueType mask) const { return (m_flags & mask) != 0; }
102 
103  /// Test a single flag bit.
104  ///
105  /// \return
106  /// \b true if \a bit is set, \b false otherwise.
107  bool Test(ValueType bit) const { return (m_flags & bit) != 0; }
108 
109  /// Test if all bits in \a mask are clear.
110  ///
111  /// \return
112  /// \b true if \b all flags in \a mask are clear, \b false
113  /// otherwise.
114  bool AllClear(ValueType mask) const { return (m_flags & mask) == 0; }
115 
116  bool AnyClear(ValueType mask) const { return (m_flags & mask) != mask; }
117 
118  /// Test a single flag bit to see if it is clear (zero).
119  ///
120  /// \return
121  /// \b true if \a bit is 0, \b false otherwise.
122  bool IsClear(ValueType bit) const { return (m_flags & bit) == 0; }
123 
124  /// Get the number of zero bits in \a m_flags.
125  ///
126  /// \return
127  /// The number of bits that are set to 0 in the current flags.
128  size_t ClearCount() const {
129  size_t count = 0;
130  for (ValueType shift = 0; shift < sizeof(ValueType) * 8; ++shift) {
131  if ((m_flags & (1u << shift)) == 0)
132  ++count;
133  }
134  return count;
135  }
136 
137  /// Get the number of one bits in \a m_flags.
138  ///
139  /// \return
140  /// The number of bits that are set to 1 in the current flags.
141  size_t SetCount() const {
142  size_t count = 0;
143  for (ValueType mask = m_flags; mask; mask >>= 1) {
144  if (mask & 1u)
145  ++count;
146  }
147  return count;
148  }
149 
150 protected:
151  ValueType m_flags; ///< The flags.
152 };
153 
154 } // namespace lldb_private
155 
156 #endif // liblldb_Flags_h_
uint32_t ValueType
The value type for flags is a 32 bit unsigned integer type.
Definition: Flags.h:25
Enumerations for broadcasting.
Definition: SBLaunchInfo.h:14
bool AnyClear(ValueType mask) const
Definition: Flags.h:116
void Reset(ValueType flags)
Set accessor for all flags.
Definition: Flags.h:63
bool AnySet(ValueType mask) const
Test one or more flags.
Definition: Flags.h:101
ValueType Clear(ValueType mask=~(ValueType) 0)
Clear one or more flags.
Definition: Flags.h:72
static uint32_t bit(const uint32_t val, const uint32_t msbit)
Definition: ARMUtils.h:269
bool Test(ValueType bit) const
Test a single flag bit.
Definition: Flags.h:107
~Flags()
Destructor.
Definition: Flags.h:45
ValueType Get() const
Get accessor for all flags.
Definition: Flags.h:51
ValueType Set(ValueType mask)
Set one or more flags by logical OR&#39;ing mask with the current flags.
Definition: Flags.h:84
bool AllSet(ValueType mask) const
Test if all bits in mask are 1 in the current flags.
Definition: Flags.h:94
A class to manage flags.
Definition: Flags.h:22
Flags(ValueType flags=0)
Construct with initial flag bit values.
Definition: Flags.h:34
size_t ClearCount() const
Get the number of zero bits in m_flags.
Definition: Flags.h:128
Flags(const Flags &rhs)
Copy constructor.
Definition: Flags.h:42
bool AllClear(ValueType mask) const
Test if all bits in mask are clear.
Definition: Flags.h:114
bool IsClear(ValueType bit) const
Test a single flag bit to see if it is clear (zero).
Definition: Flags.h:122
size_t GetBitSize() const
Return the number of flags that can be represented in this object.
Definition: Flags.h:57
size_t SetCount() const
Get the number of one bits in m_flags.
Definition: Flags.h:141
ValueType m_flags
The flags.
Definition: Flags.h:151