StatisticsParserATNSimulator.java 文件源码

@Override
protected int execDFA(DFA dfa, TokenStream input, int startIndex, SimulatorState state) {
    int result = super.execDFA(dfa, input, startIndex, state);
    if (!reportedLookahead) {
        int stopIndex = input.index();
        int k;
        if (startIndex == stopIndex) {
            k = 1;
        } else if (startIndex == stopIndex - 1) {
            k = 2;
        } else {
            k = 0;
            for (int i = startIndex; i <= stopIndex; i++) {
                input.seek(i);
                if (input.LT(1).getChannel() == Token.DEFAULT_CHANNEL) {
                    k++;
                }
            }
        }

        if (!state.useContext) {
            totalLookaheadSll[dfa.decision] += k;
            minLookaheadSll[dfa.decision] = Math.min(minLookaheadSll[dfa.decision], k);
            maxLookaheadSll[dfa.decision] = Math.max(maxLookaheadSll[dfa.decision], k);
        }
        else {
            totalLookaheadLl[dfa.decision] += k;
            minLookaheadLl[dfa.decision] = Math.min(minLookaheadLl[dfa.decision], k);
            maxLookaheadLl[dfa.decision] = Math.max(maxLookaheadLl[dfa.decision], k);
        }

        reportedLookahead = true;
    }

    return result;
}