private void dataBufferAppend(char[] ch, int start, int length) {
        dataBuffer = (char[]) extendArray(dataBuffer, dataBuffer.length,
                dataBufferPos + length);

        System.arraycopy(ch, start, dataBuffer, dataBufferPos, length);
        dataBufferPos += length;
    }
Append (part of) a character array to the data buffer.
src/nu/validator/gnu/xml/aelfred2/XmlParser.java