1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
|
//! [0]
bool function(const T &t);
//! [0]
//! [1]
bool allLowerCase(const QString &string)
{
return string.lowered() == string;
}
QStringList strings = ...;
QFuture<QString> lowerCaseStrings = QtConcurrent::filtered(strings, allLowerCase);
//! [1]
//! [2]
QStringList strings = ...;
QFuture<void> future = QtConcurrent::filter(strings, allLowerCase);
//! [2]
//! [3]
V function(T &result, const U &intermediate)
//! [3]
//! [4]
void addToDictionary(QSet<QString> &dictionary, const QString &string)
{
dictionary.insert(string);
}
QStringList strings = ...;
QFuture<QSet<QString> > dictionary = QtConcurrent::filteredReduced(strings, allLowerCase, addToDictionary);
//! [4]
//! [5]
QStringList strings = ...;
QFuture<QString> lowerCaseStrings = QtConcurrent::filtered(strings.constBegin(), strings.constEnd(), allLowerCase);
// filter in-place only works on non-const iterators
QFuture<void> future = QtConcurrent::filter(strings.begin(), strings.end(), allLowerCase);
QFuture<QSet<QString> > dictionary = QtConcurrent::filteredReduced(strings.constBegin(), strings.constEnd(), allLowerCase, addToDictionary);
//! [5]
//! [6]
QStringList strings = ...;
// each call blocks until the entire operation is finished
QStringList lowerCaseStrings = QtConcurrent::blockingFiltered(strings, allLowerCase);
QtConcurrent::blockingFilter(strings, allLowerCase);
QSet<QString> dictionary = QtConcurrent::blockingFilteredReduced(strings, allLowerCase, addToDictionary);
//! [6]
//! [7]
// keep only images with an alpha channel
QList<QImage> images = ...;
QFuture<void> alphaImages = QtConcurrent::filter(strings, &QImage::hasAlphaChannel);
// keep only gray scale images
QList<QImage> images = ...;
QFuture<QImage> grayscaleImages = QtConcurrent::filtered(images, &QImage::isGrayscale);
// create a set of all printable characters
QList<QChar> characters = ...;
QFuture<QSet<QChar> > set = QtConcurrent::filteredReduced(characters, &QChar::isPrint, &QSet<QChar>::insert);
//! [7]
//! [8]
// can mix normal functions and member functions with QtConcurrent::filteredReduced()
// create a dictionary of all lower cased strings
extern bool allLowerCase(const QString &string);
QStringList strings = ...;
QFuture<QSet<int> > averageWordLength = QtConcurrent::filteredReduced(strings, allLowerCase, QSet<QString>::insert);
// create a collage of all gray scale images
extern void addToCollage(QImage &collage, const QImage &grayscaleImage);
QList<QImage> images = ...;
QFuture<QImage> collage = QtConcurrent::filteredReduced(images, &QImage::isGrayscale, addToCollage);
//! [8]
//! [9]
bool QString::contains(const QRegExp ®exp) const;
//! [9]
//! [10]
boost::bind(&QString::contains, QRegExp("^\\S+$")); // matches strings without whitespace
//! [10]
//! [11]
bool contains(const QString &string)
//! [11]
//! [12]
QStringList strings = ...;
boost::bind(static_cast<bool(QString::*)(const QRegExp&)>( &QString::contains ), QRegExp("..." ));
//! [12]
//! [13]
struct StartsWith
{
StartsWith(const QString &string)
: m_string(string) { }
typedef bool result_type;
bool operator()(const QString &testString)
{
return testString.startsWith(m_string);
}
QString m_string;
};
QList<QString> strings = ...;
QFuture<QString> fooString = QtConcurrent::filtered(images, StartsWith(QLatin1String("Foo")));
//! [13]
|
