import java.util.*;

/**
 * CWE-407 unit test for wireshark defect.
 *
 * wireshark-0001: proto_data.c — per-packet proto data GSList O(N) lookup
 *   p_set_proto_data / p_get_proto_data / p_remove_proto_data each do
 *   g_slist_find_custom(pinfo->proto_data, ...) — O(N) scan over all
 *   per-packet protocol data entries. Called repeatedly per dissector layer.
 *
 *   Fix: replace GSList with wmem_map_t keyed by (proto<<32 | key) → O(1).
 */
public class WiresharkTest {

    // Simulate GSList-based proto_data (defect)
    static class ProtoDataList {
        private final List<long[]> entries = new ArrayList<>();  // [proto, key, data_id]

        void set(int proto, long key, long data) {
            long compKey = ((long) proto << 32) | (key & 0xFFFFFFFFL);
            for (long[] e : entries) {           // O(N) scan
                if (e[0] == compKey) { e[1] = data; return; }
            }
            entries.add(new long[]{compKey, data});
        }

        long get(int proto, long key) {
            long compKey = ((long) proto << 32) | (key & 0xFFFFFFFFL);
            for (long[] e : entries) {           // O(N) scan
                if (e[0] == compKey) return e[1];
            }
            return -1;
        }
    }

    // Simulate wmem_map_t-based proto_data (fix)
    static class ProtoDataMap {
        private final Map<Long, Long> map = new HashMap<>();

        void set(int proto, long key, long data) {
            map.put(((long) proto << 32) | (key & 0xFFFFFFFFL), data);
        }

        long get(int proto, long key) {
            Long v = map.get(((long) proto << 32) | (key & 0xFFFFFFFFL));
            return v != null ? v : -1;
        }
    }

    static void testWireshark0001() throws Exception {
        int N = 300;   // dissector layers per packet (complex capture)
        int PROTOS = 50;
        Random rng = new Random(42);

        // build test data: N (proto, key, value) tuples
        int[][] queries = new int[N][2];
        for (int i = 0; i < N; i++) {
            queries[i][0] = rng.nextInt(PROTOS);
            queries[i][1] = rng.nextInt(1000);
        }

        // correctness: both implementations return same values after inserts
        ProtoDataList plist = new ProtoDataList();
        ProtoDataMap  pmap  = new ProtoDataMap();
        for (int i = 0; i < N; i++) {
            plist.set(queries[i][0], queries[i][1], i);
            pmap.set(queries[i][0], queries[i][1], i);
        }
        for (int i = 0; i < N; i++) {
            long vlist = plist.get(queries[i][0], queries[i][1]);
            long vmap  = pmap.get(queries[i][0], queries[i][1]);
            assert vlist == vmap : "mismatch at " + i + ": " + vlist + " vs " + vmap;
        }

        // performance: simulate per-packet dissection — build once, many repeated lookups
        // (dissectors call p_get_proto_data repeatedly on the same pinfo per packet)
        long t0 = System.nanoTime();
        for (int pkt = 0; pkt < 200; pkt++) {
            ProtoDataList pd = new ProtoDataList();
            for (int i = 0; i < N; i++) pd.set(queries[i][0], queries[i][1], i);
            // simulate many get calls on a fully-populated list (N entries → each get is O(N/2))
            for (int rep = 0; rep < 50; rep++)
                for (int i = 0; i < N; i++) pd.get(queries[i][0], queries[i][1]);
        }
        long tList = System.nanoTime() - t0;

        t0 = System.nanoTime();
        for (int pkt = 0; pkt < 200; pkt++) {
            ProtoDataMap pd = new ProtoDataMap();
            for (int i = 0; i < N; i++) pd.set(queries[i][0], queries[i][1], i);
            for (int rep = 0; rep < 50; rep++)
                for (int i = 0; i < N; i++) pd.get(queries[i][0], queries[i][1]);
        }
        long tMap = System.nanoTime() - t0;

        double ratio = (double) tList / tMap;
        System.out.printf("wireshark-0001: list=%.3fs map=%.3fs ratio=%.1f×%n",
                tList / 1e9, tMap / 1e9, ratio);
        assert ratio > 5 : "Expected >5× speedup, got " + ratio;
        System.out.println("PASS wireshark-0001");
    }

    public static void main(String[] args) throws Exception {
        testWireshark0001();
        System.out.println("ALL PASS");
    }
}