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39
40#ifndef QENDIAN_P_H
41#define QENDIAN_P_H
42
43//
44// W A R N I N G
45// -------------
46//
47// This file is not part of the Qt API. It exists purely as an
48// implementation detail. This header file may change from version to
49// version without notice, or even be removed.
50//
51// We mean it.
52//
53
54#include <QtCore/qendian.h>
55
56QT_BEGIN_NAMESPACE
57
58// Note if using multiple of these bitfields in a union; the underlying storage type must
59// match. Since we always use an unsigned storage type, unsigned and signed versions may
60// be used together, but different bit-widths may not.
61template<class S, int pos, int width>
62class QSpecialIntegerBitfield
63{
64protected:
65 typedef typename S::StorageType T;
66 typedef typename std::make_unsigned<T>::type UT;
67
68 static Q_DECL_CONSTEXPR UT mask()
69 {
70 return ((UT(1) << width) - 1) << pos;
71 }
72public:
73 // FIXME: val is public until qtdeclarative is fixed to not access it directly.
74 UT val;
75
76 QSpecialIntegerBitfield &operator =(T t)
77 {
78 UT i = S::fromSpecial(val);
79 i &= ~mask();
80 i |= (UT(t) << pos) & mask();
81 val = S::toSpecial(i);
82 return *this;
83 }
84 operator T() const
85 {
86 if (std::is_signed<T>::value) {
87 UT i = S::fromSpecial(val);
88 i <<= (sizeof(T) * 8) - width - pos;
89 T t = T(i);
90 t >>= (sizeof(T) * 8) - width;
91 return t;
92 }
93 return (S::fromSpecial(val) & mask()) >> pos;
94 }
95
96 bool operator !() const { return !(val & S::toSpecial(mask())); }
97 bool operator ==(QSpecialIntegerBitfield<S, pos, width> i) const
98 { return ((val ^ i.val) & S::toSpecial(mask())) == 0; }
99 bool operator !=(QSpecialIntegerBitfield<S, pos, width> i) const
100 { return ((val ^ i.val) & S::toSpecial(mask())) != 0; }
101
102 QSpecialIntegerBitfield &operator +=(T i)
103 { return (*this = (T(*this) + i)); }
104 QSpecialIntegerBitfield &operator -=(T i)
105 { return (*this = (T(*this) - i)); }
106 QSpecialIntegerBitfield &operator *=(T i)
107 { return (*this = (T(*this) * i)); }
108 QSpecialIntegerBitfield &operator /=(T i)
109 { return (*this = (T(*this) / i)); }
110 QSpecialIntegerBitfield &operator %=(T i)
111 { return (*this = (T(*this) % i)); }
112 QSpecialIntegerBitfield &operator |=(T i)
113 { return (*this = (T(*this) | i)); }
114 QSpecialIntegerBitfield &operator &=(T i)
115 { return (*this = (T(*this) & i)); }
116 QSpecialIntegerBitfield &operator ^=(T i)
117 { return (*this = (T(*this) ^ i)); }
118 QSpecialIntegerBitfield &operator >>=(T i)
119 { return (*this = (T(*this) >> i)); }
120 QSpecialIntegerBitfield &operator <<=(T i)
121 { return (*this = (T(*this) << i)); }
122};
123
124template<typename T, int pos, int width>
125using QLEIntegerBitfield = QSpecialIntegerBitfield<QLittleEndianStorageType<T>, pos, width>;
126
127template<typename T, int pos, int width>
128using QBEIntegerBitfield = QSpecialIntegerBitfield<QBigEndianStorageType<T>, pos, width>;
129
130template<int pos, int width>
131using qint32_le_bitfield = QLEIntegerBitfield<int, pos, width>;
132template<int pos, int width>
133using quint32_le_bitfield = QLEIntegerBitfield<uint, pos, width>;
134template<int pos, int width>
135using qint32_be_bitfield = QBEIntegerBitfield<int, pos, width>;
136template<int pos, int width>
137using quint32_be_bitfield = QBEIntegerBitfield<uint, pos, width>;
138
139
140QT_END_NAMESPACE
141
142#endif // QENDIAN_P_H
143

source code of qtbase/src/corelib/global/qendian_p.h