for (int i = 0; i < size; i++) {
          keys[i] = rng.nextInt();
        }
        return createTreap(Ints.asList(keys));
      }

      // See http://en.wikipedia.org/wiki/Treap for details on the algorithm.
      private Optional<BinaryNode> createTreap(List<Integer> keys) {
        if (keys.isEmpty()) {
          return Optional.absent();
        }
        int minIndex = 0;
        for (int i = 1; i < keys.size(); i++) {

  }

  /**
   * Returns a {@link Collection} of all the permutations of the specified {@link Iterable}.
   *
   * <p><i>Notes:</i> This is an implementation of the algorithm for Lexicographical Permutations
   * Generation, described in Knuth's "The Art of Computer Programming", Volume 4, Chapter 7,
   * Section 7.2.1.2. The iteration order follows the lexicographical order. This means that the

                    // More than one filtered value, and we don't know how to handle at least one of them.
                    // TODO: add a plugin mechanism for allowing plugin to specify their selection algorithm.
                    return Optional.empty();
                }
            }
        }
        if (classes & modules) {
            selected = getPathType(path);
        }

 * based on these entries.
 * <p>
 * To fully understand the information exposed by this class a description
 * of the access check algorithm used by Windows is required. The following
 * is a basic description of the algorithm. For a more complete description
 * we recommend reading the section on Access Control in Keith Brown's
 * "The .NET Developer's Guide to Windows Security" (which is also

                    // More than one filtered value, and we don't know how to handle at least one of them.
                    // TODO: add a plugin mechanism for allowing plugin to specify their selection algorithm.
                    return Optional.empty();
                }
            }
        }
        if (classes & modules) {
            selected = getPathType(path);
        }

                file.deleteOnExit();
            }
        }
    }

    private ChecksumObserver addChecksumObserver(Wagon wagon, String algorithm) throws TransferFailedException {
        try {
            ChecksumObserver checksumObserver = new ChecksumObserver(algorithm);
            wagon.addTransferListener(checksumObserver);
            return checksumObserver;
        } catch (NoSuchAlgorithmException e) {

                }
                return calculateMacHMACAES(usage, key, data);
            }
            else {
                throw new PACDecodingException("Invalid MAC algorithm");
            }
        }
        catch ( GeneralSecurityException e ) {
            throw new PACDecodingException("Failed to calculate MAC", e);
        }
    }

        for (int i = 0; i < size; i++) {
          keys[i] = rng.nextInt();
        }
        return createTreap(Ints.asList(keys));
      }

      // See http://en.wikipedia.org/wiki/Treap for details on the algorithm.
      private Optional<BinaryNode> createTreap(List<Integer> keys) {
        if (keys.isEmpty()) {
          return Optional.absent();
        }
        int minIndex = 0;
        for (int i = 1; i < keys.size(); i++) {

      return b;
    } else if (b == 0) {
      return a; // similar logic
    }
    /*
     * Uses the binary GCD algorithm; see http://en.wikipedia.org/wiki/Binary_GCD_algorithm. This is
     * >60% faster than the Euclidean algorithm in benchmarks.
     */
    int aTwos = Long.numberOfTrailingZeros(a);
    a >>= aTwos; // divide out all 2s
    int bTwos = Long.numberOfTrailingZeros(b);

// TODO(kevinb): this class still needs some design-and-document-for-inheritance love
@ElementTypesAreNonnullByDefault
abstract class AbstractStreamingHasher extends AbstractHasher {
  /** Buffer via which we pass data to the hash algorithm (the implementor) */
  private final ByteBuffer buffer;

  /** Number of bytes to be filled before process() invocation(s). */
  private final int bufferSize;

  /** Number of bytes processed per process() invocation. */