private int writeEncryptedFrame()

in src/main/java/com/amazonaws/encryptionsdk/internal/FrameEncryptionHandler.java [260:307]
35 lines of code
6 McCabe index (conditional complexity)

  private int writeEncryptedFrame(
      final byte[] input, final int off, final int len, final byte[] out, final int outOff)
      throws BadCiphertextException, AwsCryptoException {
    if (frameNumber_ > Constants.MAX_FRAME_NUMBER
        // Make sure we have the appropriate flag set for the final frame; we don't want to accept
        // non-final-frame data when there won't be a subsequent frame for it to go into.
        || (frameNumber_ == Constants.MAX_FRAME_NUMBER && !isFinalFrame_)) {
      throw new AwsCryptoException("Frame number exceeded the maximum allowed value.");
    }

    if (out.length == 0) {
      return 0;
    }

    int outLen = 0;

    byte[] contentAad;
    if (isFinalFrame_ == true) {
      contentAad =
          Utils.generateContentAad(
              messageId_, Constants.FINAL_FRAME_STRING_ID, (int) frameNumber_, len);
    } else {
      contentAad =
          Utils.generateContentAad(
              messageId_, Constants.FRAME_STRING_ID, (int) frameNumber_, frameSize_);
    }

    final byte[] nonce = getNonce();

    final byte[] encryptedBytes = cipherHandler_.cipherData(nonce, contentAad, input, off, len);

    // create the cipherblock headers now for the encrypted data
    final int encryptedContentLen = encryptedBytes.length - tagLenBytes_;
    final CipherFrameHeaders cipherFrameHeaders =
        new CipherFrameHeaders((int) frameNumber_, nonce, encryptedContentLen, isFinalFrame_);
    final byte[] cipherFrameHeaderBytes = cipherFrameHeaders.toByteArray();

    // assemble the headers and the encrypted bytes into a single block
    System.arraycopy(
        cipherFrameHeaderBytes, 0, out, outOff + outLen, cipherFrameHeaderBytes.length);
    outLen += cipherFrameHeaderBytes.length;
    System.arraycopy(encryptedBytes, 0, out, outOff + outLen, encryptedBytes.length);
    outLen += encryptedBytes.length;

    frameNumber_++;

    return outLen;
  }