Utils: Add iterator constructors to small string

Change-Id: Ib8fcacd5dc520842cf5cee73ea21c021221158ca
Reviewed-by: Tim Jenssen <tim.jenssen@qt.io>

src/libs/utils/smallstring.h

@@ -127,6 +127,16 @@ public:
         : SmallString(SmallString::fromQString(qString))
     {}
 
+    template<typename BeginIterator,
+             typename EndIterator,
+             typename = typename std::enable_if<std::is_same<BeginIterator, EndIterator>::value>::type
+             >
+    SmallString(BeginIterator begin, EndIterator end)
+        : SmallString(&(*begin), size_type(end - begin))
+    {
+    }
+
+
     ~SmallString() noexcept
     {
         if (Q_UNLIKELY(hasAllocatedMemory()))

tests/unit/unittest/smallstringtest.cpp

@@ -80,6 +80,33 @@ TEST(SmallString, ShortSmallStringIsShortSmallString)
 #endif
 }
 
+TEST(SmallString, CreateFromCStringIterators)
+{
+    char sourceText[] = "this is very very very very very much text";
+
+    SmallString text(sourceText, &sourceText[sizeof(sourceText) - 1]);
+
+    ASSERT_THAT(text, SmallString("this is very very very very very much text"));
+}
+
+TEST(SmallString, CreateFromQByteArrayIterators)
+{
+    QByteArray sourceText = "this is very very very very very much text";
+
+    SmallString text(sourceText.begin(), sourceText.end());
+
+    ASSERT_THAT(text, SmallString("this is very very very very very much text"));
+}
+
+TEST(SmallString, CreateFromSmallStringIterators)
+{
+    SmallString sourceText = "this is very very very very very much text";
+
+    SmallString text(sourceText.begin(), sourceText.end());
+
+    ASSERT_THAT(text, SmallString("this is very very very very very much text"));
+}
+
 TEST(SmallString, ShortSmallStringIsReference)
 {
     SmallString longText("very very very very very long text");