ClangFormat: Refactor code

Reorder some functions, remove code duplication.

Change-Id: I33e118e567dee7db622bbc99e6a7c500db54e5c5
Reviewed-by: Marco Bubke <marco.bubke@qt.io>

src/libs/utils/textutils.cpp

@@ -165,5 +165,27 @@ int utf8NthLineOffset(const QTextDocument *textDocument, const QByteArray &buffe
     return utf8Offset;
 }
 
+LineColumn utf16LineColumn(const QByteArray &utf8Buffer, int utf8Offset)
+{
+    Utils::LineColumn lineColumn;
+    lineColumn.line = static_cast<int>(
+                          std::count(utf8Buffer.begin(), utf8Buffer.begin() + utf8Offset, '\n'))
+                      + 1;
+    const int startOfLineOffset = utf8Buffer.lastIndexOf('\n', utf8Offset - 1) + 1;
+    lineColumn.column = QString::fromUtf8(
+                            utf8Buffer.mid(startOfLineOffset, utf8Offset - startOfLineOffset))
+                            .length()
+                        + 1;
+    return lineColumn;
+}
+
+QString utf16LineTextInUtf8Buffer(const QByteArray &utf8Buffer, int currentUtf8Offset)
+{
+    const int lineStartUtf8Offset = utf8Buffer.lastIndexOf('\n', currentUtf8Offset - 1) + 1;
+    const int lineEndUtf8Offset = utf8Buffer.indexOf('\n', currentUtf8Offset);
+    return QString::fromUtf8(
+        utf8Buffer.mid(lineStartUtf8Offset, lineEndUtf8Offset - lineStartUtf8Offset));
+}
+
 } // Text
 } // Utils