Add QStringView::count(...)

Also this one as a porting aid towards Qt 6. The implementation is
using QString to keep things simple.

Task-number: QTBUG-86516
Change-Id: Ic033b8678c76a608af8acfc5fab547aeb159933e
Reviewed-by: Sona Kurazyan <sona.kurazyan@qt.io>
Reviewed-by: Mårten Nordheim <marten.nordheim@qt.io>
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>

3 files changed, 43 insertions, 0 deletions

diff --git a/src/corelib/text/qstring.h b/src/corelib/text/qstring.h
index f48777d7f1..7906aeaffc 100644
--- a/src/corelib/text/qstring.h
+++ b/src/corelib/text/qstring.h
@@ -2121,6 +2121,11 @@ QString QLatin1String::arg(Args &&...args) const
     return QtPrivate::argToQStringDispatch(*this, QtPrivate::qStringLikeToArg(args)...);
 }
 
+inline qsizetype QStringView::count(QChar c, Qt::CaseSensitivity cs) const noexcept
+{ return toString().count(c, cs); }
+inline qsizetype QStringView::count(QStringView s, Qt::CaseSensitivity cs) const noexcept
+{ return toString().count(s.toString(), cs); }
+
 inline short QStringView::toShort(bool *ok, int base) const
 { return toString().toShort(ok, base); }
 inline ushort QStringView::toUShort(bool *ok, int base) const
diff --git a/src/corelib/text/qstringview.cpp b/src/corelib/text/qstringview.cpp
index f3712a412a..1cbfb90d0f 100644
--- a/src/corelib/text/qstringview.cpp
+++ b/src/corelib/text/qstringview.cpp
@@ -936,6 +936,41 @@ QT_BEGIN_NAMESPACE
 */
 
 /*!
+    \fn qsizetype QStringView::count(QChar ch, Qt::CaseSensitivity cs) const noexcept
+
+    \since 5.15.2
+
+    Returns the number of occurrences of the character \a ch in the
+    string reference.
+
+    If \a cs is Qt::CaseSensitive (default), the search is
+    case sensitive; otherwise the search is case insensitive.
+
+    \note This method has been added in 5.15.2 to simplify writing code that is portable
+    between Qt 5.15 and Qt 6. The implementation is not tuned for performance in Qt 5.
+
+    \sa QString::count(), contains(), indexOf()
+*/
+
+/*!
+    \fn qsizetype QStringView::count(QStringView str, Qt::CaseSensitivity cs) const noexcept
+
+    \since 5.15.2
+    \overload
+
+    Returns the number of (potentially overlapping) occurrences of the
+    string reference \a str in this string reference.
+
+    If \a cs is Qt::CaseSensitive (default), the search is
+    case sensitive; otherwise the search is case insensitive.
+
+    \note This method has been added in 5.15.2 to simplify writing code that is portable
+    between Qt 5.15 and Qt 6. The implementation is not tuned for performance in Qt 5.
+
+    \sa QString::count(), contains(), indexOf()
+*/
+
+/*!
   \fn qint64 QStringView::toLongLong(bool *ok, int base) const
 
     Returns the string converted to a \c{long long} using base \a
diff --git a/src/corelib/text/qstringview.h b/src/corelib/text/qstringview.h
index 5e561d88a8..38a6a43219 100644
--- a/src/corelib/text/qstringview.h
+++ b/src/corelib/text/qstringview.h
@@ -300,6 +300,9 @@ public:
     { return indexOf(s, 0, cs) != qsizetype(-1); }
     Q_REQUIRED_RESULT inline bool contains(QLatin1String s, Qt::CaseSensitivity cs = Qt::CaseSensitive) const noexcept;
 
+    Q_REQUIRED_RESULT inline qsizetype count(QChar c, Qt::CaseSensitivity cs = Qt::CaseSensitive) const noexcept;
+    Q_REQUIRED_RESULT inline qsizetype count(QStringView s, Qt::CaseSensitivity cs = Qt::CaseSensitive) const noexcept;
+
     Q_REQUIRED_RESULT qsizetype lastIndexOf(QChar c, qsizetype from = -1, Qt::CaseSensitivity cs = Qt::CaseSensitive) const noexcept
     { return QtPrivate::lastIndexOf(*this, from, QStringView(&c, 1), cs); }
     Q_REQUIRED_RESULT qsizetype lastIndexOf(QStringView s, qsizetype from = -1, Qt::CaseSensitivity cs = Qt::CaseSensitive) const noexcept