예제 #1
0
  /**
   * Algorithm of Tarjan for computing the strongly connected components of a graph.
   *
   * @param v current node
   * @throws QueryException if a variable directly calls itself
   */
  private void tarjan(final int v) throws QueryException {
    final int ixv = 2 * v, llv = ixv + 1, idx = next++;
    while (list.size() <= llv) list.add(-1);
    list.set(ixv, idx);
    list.set(llv, idx);

    stack.push(v);

    for (final int w : adjacentTo(v)) {
      final int ixw = 2 * w, llw = ixw + 1;
      if (list.size() <= ixw || list.get(ixw) < 0) {
        // Successor w has not yet been visited; recurse on it
        tarjan(w);
        list.set(llv, Math.min(list.get(llv), list.get(llw)));
      } else if (stack.contains(w)) {
        // Successor w is in stack S and hence in the current SCC
        list.set(llv, Math.min(list.get(llv), list.get(ixw)));
      }
    }

    // If v is a root node, pop the stack and generate an SCC
    if (list.get(llv) == list.get(ixv)) {
      int w;
      Scope[] out = null;
      do {
        w = stack.pop();
        final Scope scp = scopes.get(w);
        out = out == null ? new Scope[] {scp} : Array.add(out, scp);
      } while (w != v);
      result.add(out);
    }
  }
예제 #2
0
 /**
  * Removes values from the index.
  *
  * @param key key
  * @param vals sorted values
  */
 void delete(final byte[] key, final int... vals) {
   final int id = values.id(key), vl = vals.length, l = lenList.get(id), s = l - vl;
   final int[] ids = idsList.get(id);
   for (int i = 0, n = 0, v = 0; i < l; i++) {
     if (v == vl || ids[i] != vals[v]) ids[n++] = ids[i];
     else v++;
   }
   lenList.set(id, s);
   if (s == 0) idsList.set(id, null);
 }
예제 #3
0
  /**
   * Adds values to the index.
   *
   * @param key key to be indexed
   * @param vals sorted values
   */
  void add(final byte[] key, final int... vals) {
    // token index: add values. otherwise, reference existing values
    final int id = type == IndexType.TOKEN ? values.put(key) : values.id(key), vl = vals.length;
    // updatable index: if required, resize existing arrays
    while (idsList.size() < id + 1) idsList.add(null);
    if (lenList.size() < id + 1) lenList.set(id, 0);

    final int len = lenList.get(id), size = len + vl;
    int[] ids = idsList.get(id);
    if (ids == null) {
      ids = vals;
    } else {
      if (ids.length < size) ids = Arrays.copyOf(ids, Array.newSize(size));
      System.arraycopy(vals, 0, ids, len, vl);
      if (ids[len - 1] > vals[0]) {
        if (reorder == null) reorder = new BoolList(values.size());
        reorder.set(id, true);
      }
    }
    idsList.set(id, ids);
    lenList.set(id, size);
  }