QStringIterator: port to QStringView

Pretty straightforward, as the implementation already used only
an iterator range internally.

Change-Id: I6e6b809329e2e2548bba6db414a3d107d09637d1
Reviewed-by: Giuseppe D'Angelo <giuseppe.dangelo@kdab.com>
Reviewed-by: Edward Welbourne <edward.welbourne@qt.io>

src/corelib/doc/snippets/code/src_corelib_tools_qstringiterator.cpp

@@ -58,7 +58,7 @@ int main()
 {
 //! [0]
 QString string(QStringLiteral("a string"));
-QStringIterator i(string);
+QStringIterator i(string); // implicitly converted to QStringView
 //! [0]
 
 //! [1]
@@ -71,8 +71,7 @@ while (i.hasNext())
 
 {
 //! [2]
-QString string(QStringLiteral("𝄞 is the G clef"));
-QStringIterator i(string);
+QStringIterator i(u"𝄞 is the G clef");
 qDebug() << hex << i.next(); // will print 1d11e (U+1D11E, MUSICAL SYMBOL G CLEF)
 qDebug() << hex << i.next(); // will print 20 (U+0020, SPACE)
 qDebug() << hex << i.next(); // will print 69 (U+0069, LATIN SMALL LETTER I)

src/corelib/tools/qstringiterator.qdoc

@@ -55,7 +55,7 @@
     that may be present in a QString, and return the individual Unicode code points.
 
     You can create a QStringIterator that iterates over a given
-    QString by passing the string to the QStringIterator's constructor:
+    QStringView by passing the string to the QStringIterator's constructor:
 
     \snippet code/src_corelib_tools_qstringiterator.cpp 0
 
@@ -120,12 +120,12 @@
 */
 
 /*!
-    \fn QStringIterator::QStringIterator(const QString &string)
+    \fn QStringIterator::QStringIterator(QStringView string, QStringView::size_type idx)
 
     Constructs an iterator over the contents of \a string. The iterator will point
-    before the first position in the string.
+    before position \a idx in the string.
 
-    The string \a string must remain valid while the iterator is being used.
+    The string view \a string must remain valid while the iterator is being used.
 */
 
 /*!

src/corelib/tools/qstringiterator_p.h

@@ -60,12 +60,12 @@ QT_BEGIN_NAMESPACE
 class QStringIterator
 {
     QString::const_iterator i, pos, e;
-
+    Q_STATIC_ASSERT((std::is_same<QString::const_iterator, const QChar *>::value));
 public:
-    inline explicit QStringIterator(const QString &string)
-        : i(string.constBegin()),
-          pos(string.constBegin()),
-          e(string.constEnd())
+    explicit QStringIterator(QStringView string, QStringView::size_type idx = 0)
+        : i(string.begin()),
+          pos(i + idx),
+          e(string.end())
     {
     }
 

tests/auto/corelib/tools/qstringiterator/tst_qstringiterator.cpp

@@ -326,22 +326,22 @@ void tst_QStringIterator::position()
         QLatin1Char('p')
         // codeunit count: 35
     };
+    static const int stringDataSize = sizeof(stringData) / sizeof(stringData[0]);
 
-    const QString string(stringData, sizeof(stringData) / sizeof(stringData[0]));
-    QStringIterator i(string);
+    QStringIterator i(QStringView(stringData, stringDataSize));
 
-    QCOMPARE(i.position(), string.constBegin());
+    QCOMPARE(i.position(), stringData);
     QVERIFY(i.hasNext());
     QVERIFY(!i.hasPrevious());
 
-    i.setPosition(string.constEnd());
-    QCOMPARE(i.position(), string.constEnd());
+    i.setPosition(stringData + stringDataSize);
+    QCOMPARE(i.position(), stringData + stringDataSize);
     QVERIFY(!i.hasNext());
     QVERIFY(i.hasPrevious());
 
 #define QCHAR_UNICODE_VALUE(x) ((uint)(QChar(x).unicode()))
 
-    const QString::const_iterator begin = string.constBegin();
+    const QChar *begin = stringData;
     i.setPosition(begin);
     QCOMPARE(i.position(), begin);
     QCOMPARE(i.peekNext(), QCHAR_UNICODE_VALUE(QLatin1Char('a')));