QLatin1StringView: optimize single-char case-sensitive {last,}indexOfHEADdev

We can delegate to QByteArrayView, which now has inline versions of
those two functions, so long as the input is Latin1.

Change-Id: Ica7a43f6147b49c187ccfffd179eb0f3748164b2
Reviewed-by: Ahmad Samir <[email protected]>

2 files changed, 25 insertions, 6 deletions

diff --git a/src/corelib/text/qlatin1stringview.h b/src/corelib/text/qlatin1stringview.h
index d76c5da512b..0e9e4fb3699 100644
--- a/src/corelib/text/qlatin1stringview.h
+++ b/src/corelib/text/qlatin1stringview.h
@@ -8,6 +8,7 @@
 #ifndef QLATIN1STRINGVIEW_H
 #define QLATIN1STRINGVIEW_H
 
+#include <QtCore/qbytearrayview.h>
 #include <QtCore/qchar.h>
 #include <QtCore/qcompare.h>
 #include <QtCore/qcontainerfwd.h>
@@ -124,8 +125,14 @@ public:
     { return QtPrivate::findString(*this, from, s, cs); }
     [[nodiscard]] qsizetype indexOf(QLatin1StringView s, qsizetype from = 0, Qt::CaseSensitivity cs = Qt::CaseSensitive) const noexcept
     { return QtPrivate::findString(*this, from, s, cs); }
-    [[nodiscard]] qsizetype indexOf(QChar c, qsizetype from = 0, Qt::CaseSensitivity cs = Qt::CaseSensitive) const noexcept
-    { return QtPrivate::findString(*this, from, QStringView(&c, 1), cs); }
+    [[nodiscard]] qsizetype indexOf(QChar c, qsizetype from = 0) const noexcept
+    { return c.unicode() <= 0xff ? QByteArrayView(*this).indexOf(char(c.unicode()), from) : -1; }
+    [[nodiscard]] qsizetype indexOf(QChar c, qsizetype from, Qt::CaseSensitivity cs) const noexcept
+    {
+        if (cs == Qt::CaseInsensitive)
+            return QtPrivate::findString(*this, from, QStringView(&c, 1), cs);
+        return indexOf(c, from);
+    }
 
     [[nodiscard]] bool contains(QStringView s, Qt::CaseSensitivity cs = Qt::CaseSensitive) const noexcept
     { return indexOf(s, 0, cs) != -1; }
@@ -142,10 +149,18 @@ public:
     { return lastIndexOf(s, size(), cs); }
     [[nodiscard]] qsizetype lastIndexOf(QLatin1StringView s, qsizetype from, Qt::CaseSensitivity cs = Qt::CaseSensitive) const noexcept
     { return QtPrivate::lastIndexOf(*this, from, s, cs); }
-    [[nodiscard]] qsizetype lastIndexOf(QChar c, Qt::CaseSensitivity cs = Qt::CaseSensitive) const noexcept
+    [[nodiscard]] qsizetype lastIndexOf(QChar c) const noexcept
+    { return lastIndexOf(c, -1); }
+    [[nodiscard]] qsizetype lastIndexOf(QChar c, Qt::CaseSensitivity cs) const noexcept
     { return lastIndexOf(c, -1, cs); }
-    [[nodiscard]] qsizetype lastIndexOf(QChar c, qsizetype from, Qt::CaseSensitivity cs = Qt::CaseSensitive) const noexcept
-    { return QtPrivate::lastIndexOf(*this, from, QStringView(&c, 1), cs); }
+    [[nodiscard]] qsizetype lastIndexOf(QChar c, qsizetype from) const noexcept
+    { return c.unicode() <= 0xff ? QByteArrayView(*this).lastIndexOf(char(c.unicode()), from) : -1; }
+    [[nodiscard]] qsizetype lastIndexOf(QChar c, qsizetype from, Qt::CaseSensitivity cs) const noexcept
+    {
+        if (cs == Qt::CaseInsensitive)
+            return QtPrivate::lastIndexOf(*this, from, QStringView(&c, 1), cs);
+        return lastIndexOf(c, from);
+    }
 
     [[nodiscard]] qsizetype count(QStringView str, Qt::CaseSensitivity cs = Qt::CaseSensitive) const
     { return QtPrivate::count(*this, str, cs); }
diff --git a/src/corelib/text/qlatin1stringview.qdoc b/src/corelib/text/qlatin1stringview.qdoc
index d28b61c4276..a36d7233c59 100644
--- a/src/corelib/text/qlatin1stringview.qdoc
+++ b/src/corelib/text/qlatin1stringview.qdoc
@@ -505,7 +505,8 @@
 /*!
     \fn qsizetype QLatin1StringView::indexOf(QStringView str, qsizetype from = 0, Qt::CaseSensitivity cs = Qt::CaseSensitive) const
     \fn qsizetype QLatin1StringView::indexOf(QLatin1StringView l1, qsizetype from = 0, Qt::CaseSensitivity cs = Qt::CaseSensitive) const
-    \fn qsizetype QLatin1StringView::indexOf(QChar c, qsizetype from = 0, Qt::CaseSensitivity cs = Qt::CaseSensitive) const
+    \fn qsizetype QLatin1StringView::indexOf(QChar c, qsizetype from = 0) const
+    \fn qsizetype QLatin1StringView::indexOf(QChar c, qsizetype from, Qt::CaseSensitivity cs) const
     \since 5.14
 
     Returns the index position in this Latin-1 string view of the first
@@ -540,6 +541,9 @@
 /*!
     \fn qsizetype QLatin1StringView::lastIndexOf(QStringView str, qsizetype from, Qt::CaseSensitivity cs) const
     \fn qsizetype QLatin1StringView::lastIndexOf(QLatin1StringView l1, qsizetype from, Qt::CaseSensitivity cs) const
+    \fn qsizetype QLatin1StringView::lastIndexOf(QChar c) const
+    \fn qsizetype QLatin1StringView::lastIndexOf(QChar c, Qt::CaseSensitivity cs) const
+    \fn qsizetype QLatin1StringView::lastIndexOf(QChar c, qsizetype from) const
     \fn qsizetype QLatin1StringView::lastIndexOf(QChar c, qsizetype from, Qt::CaseSensitivity cs) const
     \since 5.14