예제 #1
0
파일: LRC.java 프로젝트: pauldoo/scratch
  public void writeStream(DataInputStream input) throws IOException, NoSuchAlgorithmException {
    try {
      int bytesRead = 0;
      int bytesToSkip = 0;

      while (true) {
        final int value = input.readUnsignedByte();
        bytesRead++;
        check.nextByte(value);
        writeRaw(value);
        final int weakChecksum = check.weakChecksum();
        String strongChecksum = null;

        if (bytesToSkip > 0) {
          bytesToSkip--;
        } else {
          Map<String, Integer> weakMatches = inputBlocks.get(weakChecksum);
          if (weakMatches != null) {
            strongChecksum = check.strongChecksum();
            Integer previousOffset = weakMatches.get(strongChecksum);
            if (previousOffset != null) {
              snipRawBuffer();
              System.err.println(
                  "Using previously remembered : "
                      + previousOffset
                      + " : "
                      + (bytesRead - BLOCK_SIZE));
              writeBlock(previousOffset);
              bytesToSkip = BLOCK_SIZE - 1;
            }
          }
        }

        if ((bytesRead % BLOCK_SIZE) == 0) {
          Map<String, Integer> weakMatches = inputBlocks.get(weakChecksum);
          if (weakMatches == null) {
            weakMatches = new HashMap<String, Integer>();
            inputBlocks.put(weakChecksum, weakMatches);
          }
          if (strongChecksum == null) {
            strongChecksum = check.strongChecksum();
          }
          if (!weakMatches.containsKey(strongChecksum)) {
            weakMatches.put(strongChecksum, bytesRead - BLOCK_SIZE);
            System.err.println(
                "Remembering : "
                    + weakChecksum
                    + " : "
                    + strongChecksum
                    + " : "
                    + (bytesRead - BLOCK_SIZE));
          }
        }
      }
    } catch (EOFException e) {
      flushRaw();
    }
    System.err.println("Original data: " + rawChunks);
    System.err.println("Reused data: " + blockChunks);
  }
예제 #2
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;
  }