final String _decodeMask_(final int type) throws IllegalArgumentException {
		if (this.symbol() != type) throw new IllegalArgumentException();
		for (int symbol = this.skip(); symbol >= 0; symbol = this.skip()) {
			if (symbol == type) {
				if (this.skip() != type) {
					if (this.isParsed()) return this.target();
					throw new IllegalArgumentException();
				}
			}
			this.take(symbol);
		}
		throw new IllegalArgumentException();
	}