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39#ifndef QV4UTIL_H
40#define QV4UTIL_H
41
42//
43// W A R N I N G
44// -------------
45//
46// This file is not part of the Qt API. It exists purely as an
47// implementation detail. This header file may change from version to
48// version without notice, or even be removed.
49//
50// We mean it.
51//
52
53#include <QtCore/QBitArray>
54#include <algorithm>
55#include <vector>
56
57QT_BEGIN_NAMESPACE
58
59namespace QV4 {
60
61#if !defined(BROKEN_STD_VECTOR_BOOL_OR_BROKEN_STD_FIND)
62// Sanity:
63class BitVector
64{
65 std::vector<bool> bits;
66
67public:
68 BitVector(int size = 0, bool value = false)
69 : bits(size, value)
70 {}
71
72 void clear()
73 { bits = std::vector<bool>(bits.size(), false); }
74
75 void reserve(int size)
76 { bits.reserve(n: size); }
77
78 int size() const
79 {
80 Q_ASSERT(bits.size() < INT_MAX);
81 return static_cast<int>(bits.size());
82 }
83
84 void resize(int newSize)
85 { bits.resize(new_size: newSize); }
86
87 void resize(int newSize, bool newValue)
88 { bits.resize(new_size: newSize, x: newValue); }
89
90 void assign(int newSize, bool value)
91 { bits.assign(n: newSize, x: value); }
92
93 int findNext(int start, bool value, bool wrapAround) const
94 {
95 // The ++operator of std::vector<bool>::iterator in libc++ has a bug when using it on an
96 // iterator pointing to the last element. It will not be set to ::end(), but beyond
97 // that. (It will be set to the first multiple of the native word size that is bigger
98 // than size().)
99 //
100 // See http://llvm.org/bugs/show_bug.cgi?id=19663
101 //
102 // The work-around is to calculate the distance, and compare it to the size() to see if it's
103 // beyond the end, or take the minimum of the distance and the size.
104
105 size_t pos = std::distance(first: bits.begin(),
106 last: std::find(first: bits.begin() + start, last: bits.end(), val: value));
107 if (wrapAround && pos >= static_cast<size_t>(size()))
108 pos = std::distance(first: bits.begin(),
109 last: std::find(first: bits.begin(), last: bits.begin() + start, val: value));
110
111 pos = qMin(a: pos, b: static_cast<size_t>(size()));
112
113 Q_ASSERT(pos <= static_cast<size_t>(size()));
114 Q_ASSERT(pos < INT_MAX);
115
116 return static_cast<int>(pos);
117 }
118
119 bool at(int idx) const
120 { return bits.at(n: idx); }
121
122 void setBit(int idx)
123 { bits[idx] = true; }
124
125 void clearBit(int idx)
126 { bits[idx] = false; }
127};
128#else // Insanity:
129class BitVector
130{
131 QBitArray bits;
132
133public:
134 BitVector(int size = 0, bool value = false)
135 : bits(size, value)
136 {}
137
138 void clear()
139 { bits = QBitArray(bits.size(), false); }
140
141 void reserve(int size)
142 { Q_UNUSED(size); }
143
144 int size() const
145 { return bits.size(); }
146
147 void resize(int newSize)
148 { bits.resize(newSize); }
149
150 void resize(int newSize, bool newValue)
151 {
152 int oldSize = bits.size();
153 bits.resize(newSize);
154 bits.fill(newValue, oldSize, bits.size());
155 }
156
157 void assign(int newSize, bool value)
158 {
159 bits.resize(newSize);
160 bits.fill(value);
161 }
162
163 int findNext(int start, bool value, bool wrapAround) const
164 {
165 for (int i = start, ei = size(); i < ei; ++i) {
166 if (at(i) == value)
167 return i;
168 }
169
170 if (wrapAround) {
171 for (int i = 0, ei = start; i < ei; ++i) {
172 if (at(i) == value)
173 return i;
174 }
175 }
176
177 return size();
178 }
179
180 bool at(int idx) const
181 { return bits.at(idx); }
182
183 void setBit(int idx)
184 { bits[idx] = true; }
185
186 void clearBit(int idx)
187 { bits[idx] = false; }
188};
189#endif
190
191}
192
193QT_END_NAMESPACE
194
195#endif // QV4UTIL_H
196

source code of qtdeclarative/src/qml/compiler/qv4util_p.h