add equals(OString const &text) to Span

useful when removing RTL_CONST_STRINGPARAM

Change-Id: Ic131876a3fb38e69185342c4c7a46d536d60c8e5
Reviewed-on: https://gerrit.libreoffice.org/2256Reviewed-by: Caolán McNamara <caolanm@redhat.com>
Tested-by: Caolán McNamara <caolanm@redhat.com>

xmlreader/inc/xmlreader/span.hxx

@@ -53,6 +53,11 @@ struct OOO_DLLPUBLIC_XMLREADER Span {
         return equals(Span(textBegin, textLength));
     }
 
+    inline bool equals(rtl::OString const & text) const {
+        return rtl_str_compare_WithLength(
+            begin, length, text.getStr(), text.getLength()) == 0;
+    }
+
     rtl::OUString convertFromUtf8() const;
 };