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Diffstat (limited to 'doc/src/snippets/code/src_corelib_concurrent_qtconcurrentfilter.cpp')
-rw-r--r-- | doc/src/snippets/code/src_corelib_concurrent_qtconcurrentfilter.cpp | 131 |
1 files changed, 131 insertions, 0 deletions
diff --git a/doc/src/snippets/code/src_corelib_concurrent_qtconcurrentfilter.cpp b/doc/src/snippets/code/src_corelib_concurrent_qtconcurrentfilter.cpp new file mode 100644 index 0000000..d284d02 --- /dev/null +++ b/doc/src/snippets/code/src_corelib_concurrent_qtconcurrentfilter.cpp @@ -0,0 +1,131 @@ +//! [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] |