text: public CharsRef add(CharsRef prefix, CharsRef output) {assert prefix != null;assert output != null;if (prefix == NO_OUTPUT) {return output;} else if (output == NO_OUTPUT) {return prefix;} else {assert prefix.length > 0;assert output.length > 0;CharsRef result = new CharsRef(prefix.length + output.length);System.arraycopy(prefix.chars, prefix.offset, result.chars, 0, prefix.length);System.arraycopy(output.chars, output.offset, result.chars, prefix.length, output.length);result.length = prefix.length + output.length;return result;}}