Пример #1
0
  public static FileDesc loadFile(Path root, Path file, int blocSize)
      throws NoSuchAlgorithmException, FileNotFoundException, IOException {
    MessageDigest md = MessageDigest.getInstance("SHA-512");
    MessageDigest fileMd = MessageDigest.getInstance("SHA-512");

    FileDesc desc = new FileDesc(file.toString(), null, null);
    List<Bloc> list = new ArrayList<Bloc>();
    try (FileInputStream fis = new FileInputStream(root.resolve(file).toString())) {
      byte[] buf = new byte[blocSize];
      byte[] h;
      int s;
      while ((s = fis.read(buf)) != -1) {
        int c;
        while (s < buf.length && (c = fis.read()) != -1) buf[s++] = (byte) c;
        fileMd.update(buf, 0, s);

        // padding
        byte p = 0;
        while (s < buf.length) buf[s++] = ++p;
        h = md.digest(buf);
        Bloc bloc = new Bloc(RollingChecksum.compute(buf), new Hash(h));
        list.add(bloc);
      }
      h = fileMd.digest();
      desc.fileHash = new Hash(h);
      desc.blocs = list.toArray(new Bloc[0]);
    }
    return desc;
  }
Пример #2
0
  /** @return matching bloc B bloc -> A bloc */
  public static Map<Integer, Integer> diff(FileDesc a, FileDesc b) {
    Map<Integer, List<IndexedHash>> blocA = new HashMap<Integer, List<IndexedHash>>();
    int i = 0;
    for (Bloc bloc : a.blocs) {
      List<IndexedHash> l = blocA.get(bloc.roll);
      if (l == null) {
        l = new ArrayList<IndexedHash>();
        blocA.put(bloc.roll, l);
      }
      l.add(new IndexedHash(i++, bloc.hash));
    }

    Map<Integer, Integer> map = new HashMap<Integer, Integer>();
    loop:
    for (i = 0; i < b.blocs.length; i++) {
      Bloc blocB = b.blocs[i];
      List<IndexedHash> list = blocA.get(blocB.roll);
      if (list != null) {
        for (IndexedHash bloc : list) {
          if (blocB.hash.equals(bloc.h)) {
            map.put(i, bloc.i);
            continue loop;
          }
        }
      }
    }
    return map;
  }