text: public CharsRef subtract(CharsRef output, CharsRef inc) {assert output != null;assert inc != null;if (inc == NO_OUTPUT) {return output;} else if (inc.length == output.length) {return NO_OUTPUT;} else {assert inc.length < output.length: "inc.length=" + inc.length + " vs output.length=" + output.length;assert inc.length > 0;return new CharsRef(output.chars, output.offset + inc.length, output.length-inc.length);}}