add EncodedString::iterator::offset() and size()

src/core/EncodedString.cc

@@ -19,6 +19,16 @@ EncodedString::iterator & EncodedString::iterator::operator++()
     return *this;
 }
 
+size_t EncodedString::iterator::size() const
+{
+    if (m_offset < m_encoded_string.size())
+    {
+        return Encoding::num_bytes_in_code_point(m_encoded_string.encoding(), &m_encoded_string[m_offset]);
+    }
+    return 0u;
+}
+
+
 EncodedString::EncodedString(const uint8_t * data, size_t size, Encoding::Type encoding)
     : m_encoding(encoding),
       m_size(size)

src/core/EncodedString.h

@@ -26,6 +26,11 @@ public:
         }
         uint32_t operator*();
         iterator & operator++();
+        size_t offset() const
+        {
+            return m_offset;
+        }
+        size_t size() const;
         bool operator==(const iterator & other) const
         {
             return m_offset == other.m_offset;