public long readSignedNumIncreasing()

in sdk/src/main/java/com/google/cloud/dataflow/sdk/runners/worker/OrderedCode.java [471:541]
58 lines of code
16 McCabe index (conditional complexity)

  public long readSignedNumIncreasing() {
    if ((encodedArrays == null) || (encodedArrays.size() == 0) ||
        ((encodedArrays.get(0)).length - firstArrayPosition < 1)) {
      throw new IllegalArgumentException("Invalid encoded byte array");
    }

    byte[] store = encodedArrays.get(0);

    long xorMask = ((store[firstArrayPosition] & 0x80) == 0) ? ~0L : 0L;
    // Store first byte as an int rather than a (signed) byte -- to avoid
    // accidental byte-to-int promotion later, which would extend the byte's
    // sign bit (if any).
    int firstByte =
        (store[firstArrayPosition] & 0xff) ^ (int) (xorMask & 0xff);

    // Now calculate and test length, and set x to raw (unmasked) result.
    int len;
    long x;
    if (firstByte != 0xff) {
      len = 7 - log2Floor(firstByte ^ 0xff);
      if (store.length - firstArrayPosition < len) {
        throw new IllegalArgumentException("Invalid encoded byte array");
      }
      x = xorMask;  // Sign extend using xorMask.
      for (int i = firstArrayPosition; i < firstArrayPosition + len; i++) {
        x = (x << 8) | (store[i] & 0xff);
      }
    } else {
      len = 8;
      if (store.length - firstArrayPosition < len) {
        throw new IllegalArgumentException("Invalid encoded byte array");
      }
      int secondByte =
          (store[firstArrayPosition + 1] & 0xff) ^ (int) (xorMask & 0xff);
      if (secondByte >= 0x80) {
        if (secondByte < 0xc0) {
          len = 9;
        } else {
          int thirdByte =
              (store[firstArrayPosition + 2] & 0xff) ^ (int) (xorMask & 0xff);
          if (secondByte == 0xc0 && thirdByte < 0x80) {
            len = 10;
          } else {
            // Either len > 10 or len == 10 and #bits > 63.
            throw new IllegalArgumentException("Invalid encoded byte array");
          }
        }
        if (store.length - firstArrayPosition < len) {
          throw new IllegalArgumentException("Invalid encoded byte array");
        }
      }
      x = Longs.fromByteArray(Arrays.copyOfRange(
          store, firstArrayPosition + len - 8, firstArrayPosition + len));
    }

    x ^= LENGTH_TO_MASK[len];  // Remove spurious header bits.

    if (len != getSignedEncodingLength(x)) {
      throw new IllegalArgumentException("Invalid encoded byte array");
    }

    if ((store.length - firstArrayPosition - len) == 0) {
      // We are done with the first array.
      encodedArrays.remove(0);
      firstArrayPosition = 0;
    } else {
      firstArrayPosition = firstArrayPosition + len;
    }

    return x;
  }