Implement (and unit test) simple QVarLengthArray::first()/last().

Pure syntactical sugar, to match up with what the other container
classes offer.

Change-Id: I0f97de011923d9d204cca0fa906b059dc5054a89
Reviewed-by: João Abecasis <joao.abecasis@nokia.com>
Reviewed-by: Bradley T. Hughes <bradley.hughes@nokia.com>

src/corelib/tools/qvarlengtharray.h

@@ -96,6 +96,10 @@ public:
     inline int size() const { return s; }
     inline int count() const { return s; }
     inline int length() const { return s; }
+    inline T& first() { Q_ASSERT(!isEmpty()); return *begin(); }
+    inline const T& first() const { Q_ASSERT(!isEmpty()); return *begin(); }
+    T& last() { Q_ASSERT(!isEmpty()); return *(end() - 1); }
+    const T& last() const { Q_ASSERT(!isEmpty()); return *(end() - 1); }
     inline bool isEmpty() const { return (s == 0); }
     inline void resize(int size);
     inline void clear() { resize(0); }

src/corelib/tools/qvarlengtharray.qdoc

@@ -125,6 +125,36 @@
     \sa isEmpty(), resize()
 */
 
+/*! \fn T& QVarLengthArray::first()
+
+    Returns a reference to the first item in the array. The array must
+    not be empty. If the array can be empty, check isEmpty() before
+    calling this function.
+
+    \sa last(), isEmpty()
+*/
+
+/*! \fn const T& QVarLengthArray::first() const
+
+    \overload
+*/
+
+/*! \fn T& QVarLengthArray::last()
+
+    Returns a reference to the last item in the array.  The array must
+    not be empty. If the array can be empty, check isEmpty() before
+    calling this function.
+
+    \sa first(), isEmpty()
+*/
+
+/*! \fn const T& QVarLengthArray::last() const
+
+    \overload
+*/
+
+
+
 /*! \fn bool QVarLengthArray::isEmpty() const
 
     Returns true if the array has size 0; otherwise returns false.

tests/auto/corelib/tools/qvarlengtharray/tst_qvarlengtharray.cpp

@@ -56,6 +56,8 @@ private slots:
     void resize();
     void realloc();
     void count();
+    void first();
+    void last();
 };
 
 int fooCtor = 0;
@@ -655,5 +657,49 @@ void tst_QVarLengthArray::count()
     }
 }
 
+void tst_QVarLengthArray::first()
+{
+    // append some items, make sure it stays sane
+    QVarLengthArray<int> list;
+    list.append(27);
+    QCOMPARE(list.first(), 27);
+    list.append(4);
+    QCOMPARE(list.first(), 27);
+    list.append(1987);
+    QCOMPARE(list.first(), 27);
+    QCOMPARE(list.length(), 3);
+
+    // remove some, make sure it stays sane
+    list.removeLast();
+    QCOMPARE(list.first(), 27);
+    QCOMPARE(list.length(), 2);
+
+    list.removeLast();
+    QCOMPARE(list.first(), 27);
+    QCOMPARE(list.length(), 1);
+}
+
+void tst_QVarLengthArray::last()
+{
+    // append some items, make sure it stays sane
+    QVarLengthArray<int> list;
+    list.append(27);
+    QCOMPARE(list.last(), 27);
+    list.append(4);
+    QCOMPARE(list.last(), 4);
+    list.append(1987);
+    QCOMPARE(list.last(), 1987);
+    QCOMPARE(list.length(), 3);
+
+    // remove some, make sure it stays sane
+    list.removeLast();
+    QCOMPARE(list.last(), 4);
+    QCOMPARE(list.length(), 2);
+
+    list.removeLast();
+    QCOMPARE(list.last(), 27);
+    QCOMPARE(list.length(), 1);
+}
+
 QTEST_APPLESS_MAIN(tst_QVarLengthArray)
 #include "tst_qvarlengtharray.moc"