private void _beforeRemoveVertex(int vertex, boolean bChangePathFirst) {
    int vertexlistIndex = m_shape.getUserIndex(vertex, m_userIndexSortedIndexToVertex);
    // _ASSERT(m_sortedVertices.getData(vertexlistIndex) != 0xdeadbeef);
    if (m_nextVertexToProcess == vertexlistIndex) {
      m_nextVertexToProcess = m_sortedVertices.getNext(m_nextVertexToProcess);
    }

    if (m_firstCoincidentVertex == vertexlistIndex)
      m_firstCoincidentVertex = m_sortedVertices.getNext(m_firstCoincidentVertex);

    m_sortedVertices.deleteElement(m_sortedVerticesListIndex, vertexlistIndex);
    _removeAngleSortInfo(vertex);
    if (bChangePathFirst) {
      int path = m_shape.getPathFromVertex(vertex);
      if (path != -1) {
        int first = m_shape.getFirstVertex(path);
        if (first == vertex) {
          int next = m_shape.getNextVertex(vertex);
          if (next != vertex) m_shape.setFirstVertex_(path, next);
          else {
            m_shape.setFirstVertex_(path, -1);
            m_shape.setLastVertex_(path, -1);
          }
        }
      }
    }
  }
  private boolean _processBunch() {
    boolean bModified = false;
    int iter = 0;
    Point2D ptCenter = new Point2D();
    while (true) {
      m_dbgCounter++; // only for debugging
      iter++;
      // _ASSERT(iter < 10);
      if (m_bunchEdgeEndPoints == null) {
        m_bunchEdgeEndPoints = new AttributeStreamOfInt32(0);
        m_bunchEdgeCenterPoints = new AttributeStreamOfInt32(0);
        m_bunchEdgeIndices = new AttributeStreamOfInt32(0);
      } else {
        m_bunchEdgeEndPoints.clear(false);
        m_bunchEdgeCenterPoints.clear(false);
        m_bunchEdgeIndices.clear(false);
      }

      int currentVertex = m_firstCoincidentVertex;
      int index = 0;
      boolean bFirst = true;
      while (currentVertex != m_nextVertexToProcess) {
        int v = m_sortedVertices.getData(currentVertex);
        { // debug
          Point2D pt = new Point2D();
          m_shape.getXY(v, pt);
          double y = pt.x;
        }
        if (bFirst) {
          m_shape.getXY(v, ptCenter);
          bFirst = false;
        }
        int vertP = m_shape.getPrevVertex(v);
        int vertN = m_shape.getNextVertex(v);
        // _ASSERT(vertP != vertN || m_shape.getPrevVertex(vertN) == v
        // && m_shape.getNextVertex(vertP) == v);

        int id = m_shape.getUserIndex(vertP, m_userIndexSortedAngleIndexToVertex);
        if (id != 0xdeadbeef) // avoid adding a point twice
        {
          // _ASSERT(id == -1);
          m_bunchEdgeEndPoints.add(vertP);
          m_shape.setUserIndex(vertP, m_userIndexSortedAngleIndexToVertex, 0xdeadbeef); // mark
          // that
          // it
          // has
          // been
          // already
          // added
          m_bunchEdgeCenterPoints.add(v);
          m_bunchEdgeIndices.add(index++);
        }

        int id2 = m_shape.getUserIndex(vertN, m_userIndexSortedAngleIndexToVertex);
        if (id2 != 0xdeadbeef) // avoid adding a point twice
        {
          // _ASSERT(id2 == -1);
          m_bunchEdgeEndPoints.add(vertN);
          m_shape.setUserIndex(vertN, m_userIndexSortedAngleIndexToVertex, 0xdeadbeef); // mark
          // that
          // it
          // has
          // been
          // already
          // added
          m_bunchEdgeCenterPoints.add(v);
          m_bunchEdgeIndices.add(index++);
        }

        currentVertex = m_sortedVertices.getNext(currentVertex);
      }

      if (m_bunchEdgeEndPoints.size() < 2) break;

      // Sort the bunch edpoints by angle (angle between the axis x and
      // the edge, connecting the endpoint with the bunch center)
      m_bunchEdgeIndices.Sort(0, m_bunchEdgeIndices.size(), new SimplificatorAngleComparer(this));
      // SORTDYNAMICARRAYEX(m_bunchEdgeIndices, int, 0,
      // m_bunchEdgeIndices.size(), SimplificatorAngleComparer, this);

      for (int i = 0, n = m_bunchEdgeIndices.size(); i < n; i++) {
        int indexL = m_bunchEdgeIndices.get(i);
        int vertex = m_bunchEdgeEndPoints.get(indexL);
        m_shape.setUserIndex(vertex, m_userIndexSortedAngleIndexToVertex, i); // rember the
        // sort by angle
        // order
        { // debug
          Point2D pt = new Point2D();
          m_shape.getXY(vertex, pt);
          double y = pt.x;
        }
      }

      boolean bCrossOverResolved = _processCrossOvers(ptCenter); // see of
      // there
      // are
      // crossing
      // over
      // edges.
      for (int i = 0, n = m_bunchEdgeIndices.size(); i < n; i++) {
        int indexL = m_bunchEdgeIndices.get(i);
        if (indexL == -1) continue;
        int vertex = m_bunchEdgeEndPoints.get(indexL);
        m_shape.setUserIndex(vertex, m_userIndexSortedAngleIndexToVertex, -1); // remove
        // mapping
      }

      if (bCrossOverResolved) {
        bModified = true;
        continue;
      }

      break;
    }

    return bModified;
  }
  private void _fixOrphanVertices() {
    int pathCount = 0;
    // clean any path info
    for (int node = m_sortedVertices.getFirst(m_sortedVertices.getFirstList());
        node != -1;
        node = m_sortedVertices.getNext(node)) {
      int vertex = m_sortedVertices.getData(node);
      m_shape.setPathToVertex_(vertex, -1);
    }
    int geometrySize = 0;
    for (int path = m_shape.getFirstPath(m_geometry); path != -1; ) {
      int first = m_shape.getFirstVertex(path);
      if (first == -1 || m_shape.getPathFromVertex(first) != -1) {
        int p = path;
        path = m_shape.getNextPath(path);
        m_shape.removePathOnly_(p);
        continue;
      }

      m_shape.setPathToVertex_(first, path);
      int pathSize = 1;
      for (int vertex = m_shape.getNextVertex(first);
          vertex != first;
          vertex = m_shape.getNextVertex(vertex)) {
        // _ASSERT(m_shape.getPathFromVertex(vertex) == -1);
        m_shape.setPathToVertex_(vertex, path);
        // _ASSERT(m_shape.getNextVertex(m_shape.getPrevVertex(vertex))
        // == vertex);
        pathSize++;
      }
      m_shape.setPathSize_(path, pathSize);
      m_shape.setLastVertex_(path, m_shape.getPrevVertex(first));
      geometrySize += pathSize;
      pathCount++;
      path = m_shape.getNextPath(path);
    }

    // produce new paths for the orphan vertices.
    for (int node = m_sortedVertices.getFirst(m_sortedVertices.getFirstList());
        node != -1;
        node = m_sortedVertices.getNext(node)) {
      int vertex = m_sortedVertices.getData(node);
      if (m_shape.getPathFromVertex(vertex) != -1) continue;
      int path = m_shape.insertPath(m_geometry, -1);
      int pathSize = 0;
      int first = vertex;
      while (true) {
        m_shape.setPathToVertex_(vertex, path);
        pathSize++;
        int next = m_shape.getNextVertex(vertex);
        // _ASSERT(m_shape.getNextVertex(m_shape.getPrevVertex(vertex))
        // == vertex);
        if (next == first) break;
        vertex = next;
      }

      m_shape.setClosedPath(path, true);

      m_shape.setPathSize_(path, pathSize);
      m_shape.setFirstVertex_(path, first);
      m_shape.setLastVertex_(path, m_shape.getPrevVertex(first));
      geometrySize += pathSize;
      pathCount++;
    }
    m_shape.setGeometryPathCount_(m_geometry, pathCount);
    int totalPointCount = m_shape.getTotalPointCount() - m_shape.getPointCount(m_geometry);
    m_shape.setGeometryVertexCount_(m_geometry, geometrySize);
    m_shape.setTotalPointCount_(totalPointCount + geometrySize);
  }
  private boolean _simplify() {
    boolean bChanged = false;
    boolean bNeedWindingRepeat = true;
    boolean bWinding = false;

    m_userIndexSortedIndexToVertex = -1;
    m_userIndexSortedAngleIndexToVertex = -1;

    int pointCount = m_shape.getPointCount(m_geometry);

    // Sort vertices lexicographically
    // Firstly copy allvertices to an array.
    AttributeStreamOfInt32 verticesSorter = new AttributeStreamOfInt32(0);
    verticesSorter.reserve(pointCount);

    for (int path = m_shape.getFirstPath(m_geometry);
        path != -1;
        path = m_shape.getNextPath(path)) {
      int vertex = m_shape.getFirstVertex(path);
      for (int index = 0, n = m_shape.getPathSize(path); index < n; index++) {
        verticesSorter.add(vertex);
        vertex = m_shape.getNextVertex(vertex);
      }
    }

    // Sort
    verticesSorter.Sort(0, pointCount, new SimplificatorVertexComparer(this));
    // SORTDYNAMICARRAYEX(verticesSorter, int, 0, pointCount,
    // SimplificatorVertexComparer, this);

    // Copy sorted vertices to the m_sortedVertices list. Make a mapping
    // from the edit shape vertices to the sorted vertices.
    m_userIndexSortedIndexToVertex = m_shape.createUserIndex(); // this index
    // is used
    // to map
    // from edit
    // shape
    // vertex to
    // the
    // m_sortedVertices
    // list
    m_sortedVertices = new IndexMultiDCList();
    m_sortedVerticesListIndex = m_sortedVertices.createList(0);
    for (int i = 0; i < pointCount; i++) {
      int vertex = verticesSorter.get(i);
      { // debug
        Point2D pt = new Point2D();
        m_shape.getXY(vertex, pt); // for debugging
        double y = pt.x;
      }
      int vertexlistIndex = m_sortedVertices.addElement(m_sortedVerticesListIndex, vertex);
      m_shape.setUserIndex(
          vertex,
          m_userIndexSortedIndexToVertex,
          vertexlistIndex); // remember the sorted list element on the
      // vertex.
      // When we remove a vertex, we also remove associated sorted list
      // element.
    }

    m_userIndexSortedAngleIndexToVertex = m_shape.createUserIndex(); // create
    // additional
    // list
    // to
    // store
    // angular
    // sort
    // mapping.

    m_nextVertexToProcess = -1;

    if (_cleanupSpikes()) // cleanup any spikes on the polygon.
    bChanged = true;

    // External iteration loop for the simplificator.
    // ST. I am not sure if it actually needs this loop. TODO: figure this
    // out.
    while (bNeedWindingRepeat) {
      bNeedWindingRepeat = false;

      int max_iter =
          m_shape.getPointCount(m_geometry) + 10 > 30
              ? 1000
              : (m_shape.getPointCount(m_geometry) + 10) * (m_shape.getPointCount(m_geometry) + 10);

      // Simplify polygon
      int iRepeatNum = 0;
      boolean bNeedRepeat = false;

      // Internal iteration loop for the simplificator.
      // ST. I am not sure if it actually needs this loop. TODO: figure
      // this out.
      do // while (bNeedRepeat);
      {
        bNeedRepeat = false;

        boolean bVertexRecheck = false;
        m_firstCoincidentVertex = -1;
        int coincidentCount = 0;
        Point2D ptFirst = new Point2D();
        Point2D pt = new Point2D();
        // Main loop of the simplificator. Go through the vertices and
        // for those that have same coordinates,
        for (int vlistindex = m_sortedVertices.getFirst(m_sortedVerticesListIndex);
            vlistindex != IndexMultiDCList.nullNode(); ) {
          int vertex = m_sortedVertices.getData(vlistindex);
          { // debug
            // Point2D pt = new Point2D();
            m_shape.getXY(vertex, pt);
            double d = pt.x;
          }

          if (m_firstCoincidentVertex != -1) {
            // Point2D pt = new Point2D();
            m_shape.getXY(vertex, pt);
            if (ptFirst.isEqual(pt)) {
              coincidentCount++;
            } else {
              ptFirst.setCoords(pt);
              m_nextVertexToProcess = vlistindex; // we remeber the
              // next index in
              // the member
              // variable to
              // allow it to
              // be updated if
              // a vertex is
              // removed
              // inside of the
              // _ProcessBunch.
              if (coincidentCount > 0) {
                boolean result = _processBunch(); // process a
                // bunch of
                // coinciding
                // vertices
                if (result) { // something has changed.
                  // Note that ProcessBunch may
                  // change m_nextVertexToProcess
                  // and m_firstCoincidentVertex.
                  bNeedRepeat = true;
                  if (m_nextVertexToProcess != IndexMultiDCList.nullNode()) {
                    int v = m_sortedVertices.getData(m_nextVertexToProcess);
                    m_shape.getXY(v, ptFirst);
                  }
                }
              }

              vlistindex = m_nextVertexToProcess;
              m_firstCoincidentVertex = vlistindex;
              coincidentCount = 0;
            }
          } else {
            m_firstCoincidentVertex = vlistindex;
            m_shape.getXY(m_sortedVertices.getData(vlistindex), ptFirst);
            coincidentCount = 0;
          }

          vlistindex = m_sortedVertices.getNext(vlistindex);
        }

        m_nextVertexToProcess = -1;

        if (coincidentCount > 0) {
          boolean result = _processBunch();
          if (result) bNeedRepeat = true;
        }

        if (iRepeatNum++ > 10) {
          throw new GeometryException("internal error.");
        }

        if (bNeedRepeat) _fixOrphanVertices(); // fix broken structure of the shape

        if (_cleanupSpikes()) bNeedRepeat = true;

        bNeedWindingRepeat |= bNeedRepeat && bWinding;

        bChanged |= bNeedRepeat;

      } while (bNeedRepeat);
    } // while (bNeedWindingRepeat)

    // Now process rings. Fix ring orientation and determine rings that need
    // to be deleted.

    m_shape.removeUserIndex(m_userIndexSortedIndexToVertex);
    m_shape.removeUserIndex(m_userIndexSortedAngleIndexToVertex);

    bChanged |= RingOrientationFixer.execute(m_shape, m_geometry, m_sortedVertices);

    return bChanged;
  }