java-topology/defects/audacity/unit/AudacityTest.java

/**
 * CWE-407 simulation tests for Audacity defects.
 *
 * Each test simulates the defective O(N^2) pattern and the fixed O(N) pattern,
 * measuring operation counts to confirm the quadratic vs linear behavior.
 */
import java.util.*;

public class AudacityTest {

    static int ops;

    // ========================================================================
    // audacity-0001: TrackeditActionsController selectedTracks O(T*S)
    // ========================================================================

    /** Defective: for each track, linear scan of selectedTracks */
    static List<Integer> filterTracksDefective(List<Integer> allTracks, List<Integer> selectedTracks) {
        ops = 0;
        List<Integer> result = new ArrayList<>();
        for (int trackId : allTracks) {
            boolean found = false;
            for (int sel : selectedTracks) {
                ops++;
                if (sel == trackId) {
                    found = true;
                    break;
                }
            }
            if (found) {
                result.add(trackId);
            }
        }
        return result;
    }

    /** Fixed: HashSet for O(1) membership */
    static List<Integer> filterTracksFixed(List<Integer> allTracks, List<Integer> selectedTracks) {
        ops = 0;
        Set<Integer> selectedSet = new HashSet<>(selectedTracks);
        List<Integer> result = new ArrayList<>();
        for (int trackId : allTracks) {
            ops++;
            if (selectedSet.contains(trackId)) {
                result.add(trackId);
            }
        }
        return result;
    }

    static void testSelectedTracksFilter() {
        int T = 500, S = 100;
        List<Integer> allTracks = new ArrayList<>();
        List<Integer> selectedTracks = new ArrayList<>();
        for (int i = 0; i < T; i++) allTracks.add(i);
        // Selected tracks are the last S tracks — worst case for linear scan
        for (int i = T - S; i < T; i++) selectedTracks.add(i);

        List<Integer> r1 = filterTracksDefective(allTracks, selectedTracks);
        int defectOps = ops;

        List<Integer> r2 = filterTracksFixed(allTracks, selectedTracks);
        int fixedOps = ops;

        assert r1.size() == r2.size() : "Results must match";
        double ratio = (double) defectOps / fixedOps;
        System.out.printf("audacity-0001 selectedTracks filter  T=%d S=%d  defect=%d  fixed=%d  ratio=%.1fx%n",
                T, S, defectOps, fixedOps, ratio);
        assert ratio > 10 : "Expected >10x ratio, got " + ratio;
    }

    // ========================================================================
    // audacity-0002: WaveTrack::CanOffsetClips() O(I*M) moving clip scan
    // ========================================================================

    /** Defective: for each interval, linear scan of movingClips */
    static boolean canOffsetClipsDefective(int[] intervals, int[] movingClips, double amount) {
        ops = 0;
        for (int interval : intervals) {
            // Check if this interval is in movingClips
            boolean isMoving = false;
            for (int mc : movingClips) {
                ops++;
                if (mc == interval) {
                    isMoving = true;
                    break;
                }
            }
            if (isMoving) continue;
            // Would check overlap with moving clips here
        }
        return true;
    }

    /** Fixed: HashSet for O(1) membership */
    static boolean canOffsetClipsFixed(int[] intervals, int[] movingClips, double amount) {
        ops = 0;
        Set<Integer> movingSet = new HashSet<>();
        for (int mc : movingClips) movingSet.add(mc);
        for (int interval : intervals) {
            ops++;
            if (movingSet.contains(interval)) continue;
        }
        return true;
    }

    static void testCanOffsetClips() {
        int I = 500, M = 100;
        // All unique intervals, none are moving — worst case
        int[] intervals = new int[I];
        int[] movingClips = new int[M];
        for (int i = 0; i < I; i++) intervals[i] = i;
        for (int i = 0; i < M; i++) movingClips[i] = I + i; // none match

        canOffsetClipsDefective(intervals, movingClips, 1.0);
        int defectOps = ops;

        canOffsetClipsFixed(intervals, movingClips, 1.0);
        int fixedOps = ops;

        double ratio = (double) defectOps / fixedOps;
        System.out.printf("audacity-0002 CanOffsetClips  I=%d M=%d  defect=%d  fixed=%d  ratio=%.1fx%n",
                I, M, defectOps, fixedOps, ratio);
        assert ratio > 10 : "Expected >10x ratio, got " + ratio;
    }

    // ========================================================================
    // Main
    // ========================================================================

    public static void main(String[] args) {
        testSelectedTracksFilter();
        testCanOffsetClips();
        System.out.println("ALL 2 TESTS PASSED");
    }
}