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| author | Marc Mutz <marc.mutz@kdab.com> | 2012-05-18 20:12:35 +0200 |
|---|---|---|
| committer | The Qt Project <gerrit-noreply@qt-project.org> | 2013-04-03 11:38:35 +0200 |
| commit | 76e0223619da02911d02813961ef631a5e02d826 (patch) | |
| tree | 0fafdd9293508a89c7baed92b8d269dc93a36670 /src/corelib/tools/qalgorithms.qdoc | |
| parent | 6e7b8f79cb852ee1a6262a22aabd328b0e1b6dc0 (diff) | |
Add qPopulationCount() function, extracted from QBitArray
This functionality is used in multiple places in Qt itself, so it makes
sense to have a global function for this. This also allows to map this
onto specialized assembler instructions, should an architecture provide
them, later on.
Also added comprehensive tests, using a 4-bit lookup-table implementation
as a reference.
Change-Id: I8c4ea72cce54506ebb9fbe61141dbb5f1b7a660f
Reviewed-by: Stephen Kelly <stephen.kelly@kdab.com>
Diffstat (limited to 'src/corelib/tools/qalgorithms.qdoc')
| -rw-r--r-- | src/corelib/tools/qalgorithms.qdoc | 31 |
1 files changed, 31 insertions, 0 deletions
diff --git a/src/corelib/tools/qalgorithms.qdoc b/src/corelib/tools/qalgorithms.qdoc index cc544af868..7c3aa1a3b2 100644 --- a/src/corelib/tools/qalgorithms.qdoc +++ b/src/corelib/tools/qalgorithms.qdoc @@ -635,3 +635,34 @@ of \a value in the variable passed as a reference in argument \a n. \sa {qLess()}{qLess<T>()} */ + + +/*! + \fn uint qPopulationCount(quint8 v) + \relates <QtAlgorithms> + \since 5.2 + + Returns the number of bits set in \a v. This number also called + the Hamming Weight of \a v. + */ + +/*! + \fn uint qPopulationCount(quint16 v) + \relates <QtAlgorithms> + \since 5.2 + \overload + */ + +/*! + \fn uint qPopulationCount(quint32 v) + \relates <QtAlgorithms> + \since 5.2 + \overload + */ + +/*! + \fn uint qPopulationCount(quint64 v) + \relates <QtAlgorithms> + \since 5.2 + \overload + */ |