コード例 #1
0
ファイル: NewChunk.java プロジェクト: hihihippp/h2o
  // Compute compressed boolean buffer
  private byte[] bufB(int bpv) {
    assert bpv == 1 || bpv == 2 : "Only bit vectors with/without NA are supported";
    final int off = CBSChunk.OFF;
    int clen = off + CBSChunk.clen(_len2, bpv);
    byte bs[] = new byte[clen];
    // Save the gap = number of unfilled bits and bpv value
    bs[0] = (byte) (((_len2 * bpv) & 7) == 0 ? 0 : (8 - ((_len2 * bpv) & 7)));
    bs[1] = (byte) bpv;

    if (_len2 != _len) { // Sparse bitvector?
      assert bpv == 1; // No NAs
      for (int i = 0; i < _len; i++) {
        int row = _xs[i];
        bs[(row >> 3) + off] = CBSChunk.write1b(bs[(row >> 3) + off], (byte) 1, row & 7);
      }
      return bs;
    }

    // Dense bitvector
    int boff = 0;
    byte b = 0;
    int idx = CBSChunk.OFF;
    for (int i = 0; i < _len; i++) {
      if (bpv == 1) {
        assert !isNA(i);
        b = CBSChunk.write1b(b, (byte) _ls[i], boff);
      } else {
        byte val = isNA(i) ? CBSChunk._NA : (byte) _ls[i];
        b = CBSChunk.write2b(b, val, boff);
      }
      boff += bpv;
      if (boff > 8 - bpv) {
        bs[idx] = b;
        boff = 0;
        b = 0;
        idx++;
      }
    }
    assert bs[0] == (byte) (boff == 0 ? 0 : 8 - boff);
    // Flush last byte
    if (boff > 0) bs[idx++] = b;
    return bs;
  }