# Copies the characters of `source` to `self`.
	# A maximum of `self.capacity` code units will be copied to `self`.
	# If a code point >0xFFFF has to be divided, it will not be copied.
	fun copy_from(source: String) do
		uchar_string.from_cstring(capacity, source.to_cstring, source.byte_length)

		code_units = source.u16_length
	end