QStringRef: add chop()

chop() was missing in the API.

Change-Id: I15af86c8f218cf159b8ce19bbeb2ffa6201f98cf
Reviewed-by: Edward Welbourne <edward.welbourne@qt.io>

src/corelib/tools/qstring.cpp

@@ -5009,7 +5009,7 @@ void QString::truncate(int pos)
     If you want to remove characters from the \e beginning of the
     string, use remove() instead.
 
-    \sa truncate(), resize(), remove()
+    \sa truncate(), resize(), remove(), QStringRef::chop()
 */
 void QString::chop(int n)
 {
@@ -9659,6 +9659,18 @@ QStringRef QString::midRef(int position, int n) const
     \sa QString::truncate()
 */
 
+/*!
+    \fn void QStringRef::chop(int n)
+    \since 5.8
+
+    Removes \a n characters from the end of the string.
+
+    If \a n is greater than or equal to size(), the result is an
+    empty string; if \a n is negative, it is equivalent to passing zero.
+
+    \sa QString::chop(), truncate()
+*/
+
 /*!
   \since 4.8
 

src/corelib/tools/qstring.h

@@ -1438,6 +1438,12 @@ public:
     QStringRef mid(int pos, int n = -1) const Q_REQUIRED_RESULT;
 
     void truncate(int pos) Q_DECL_NOTHROW { m_size = qBound(0, pos, m_size); }
+    void chop(int n) Q_DECL_NOTHROW {
+        if (n >= m_size)
+            m_size = 0;
+        else if (n > 0)
+            m_size -= n;
+    }
 
     bool startsWith(const QString &s, Qt::CaseSensitivity cs = Qt::CaseSensitive) const;
     bool startsWith(QLatin1String s, Qt::CaseSensitivity cs = Qt::CaseSensitive) const;

tests/auto/corelib/tools/qstringref/tst_qstringref.cpp

@@ -81,6 +81,7 @@ private slots:
     void integer_conversion();
     void trimmed();
     void truncate();
+    void chop();
     void left();
     void right();
     void mid();
@@ -1904,6 +1905,48 @@ void tst_QStringRef::truncate()
     }
 }
 
+void tst_QStringRef::chop()
+{
+    const QString originalString = QStringLiteral("OriginalString~");
+    const QStringRef cref(&originalString);
+    {
+        const int n = 1;
+        QStringRef ref = cref;
+        QString str = originalString;
+        ref.chop(n);
+        str.chop(n);
+        QCOMPARE(ref.toString(), QLatin1String("OriginalString"));
+        QCOMPARE(ref.toString(), str);
+    }
+    {
+        const int n = -1;
+        QStringRef ref = cref;
+        QString str = originalString;
+        ref.chop(n);
+        str.chop(n);
+        QCOMPARE(ref.toString(), originalString);
+        QCOMPARE(ref.toString(), str);
+    }
+    {
+        const int n = 0;
+        QStringRef ref = cref;
+        QString str = originalString;
+        ref.chop(n);
+        str.chop(n);
+        QCOMPARE(ref.toString(), originalString);
+        QCOMPARE(ref.toString(), str);
+    }
+    {
+        const int n = 1000;
+        QStringRef ref = cref;
+        QString str = originalString;
+        ref.chop(n);
+        str.chop(n);
+        QCOMPARE(ref.toString(), str);
+        QVERIFY(ref.isEmpty());
+    }
+}
+
 void tst_QStringRef::left()
 {
     QString originalString = "OrginalString~";