String parseTokenChecked(String str, int ichStart, int ichMax) {
		int ich = ichStart;
		char ch;
		while (ich < ichMax && ((ch = str.charAt(ich)) == ' ' || ch == '\t'))
			++ich;
		int ichNonWhite = ich;
		while (ich < ichMax && ((ch = str.charAt(ich)) != ' ' && ch != '\t'))
			++ich;
		ichNextParse = ich;
		if (ichNonWhite == ich)
			return null;
		return str.substring(ichNonWhite, ich);
	}