Python TlvEncoder.writeBuffer方法代码示例

# 需要导入模块: from pyndn.encoding.tlv.tlv_encoder import TlvEncoder [as 别名]
# 或者: from pyndn.encoding.tlv.tlv_encoder.TlvEncoder import writeBuffer [as 别名]
    def wireEncode(self, wireFormat = None):
        """
        Encode this as an NDN-TLV SafeBag.

        :return: The encoded byte array as a Blob.
        :rtype: Blob
        """
        # Encode directly as TLV. We don't support the WireFormat abstraction
        # because this isn't meant to go directly on the wire.
        encoder = TlvEncoder(256)
        saveLength = len(encoder)

        # Encode backwards.
        encoder.writeBlobTlv(
          Tlv.SafeBag_EncryptedKeyBag, self._privateKeyBag.buf())
        # Add the entire Data packet encoding as is.
        encoder.writeBuffer(
          self._certificate.wireEncode(TlvWireFormat.get()).buf())

        encoder.writeTypeAndLength(
          Tlv.SafeBag_SafeBag, len(encoder) - saveLength)

        return Blob(encoder.getOutput(), False)

# 需要导入模块: from pyndn.encoding.tlv.tlv_encoder import TlvEncoder [as 别名]
# 或者: from pyndn.encoding.tlv.tlv_encoder.TlvEncoder import writeBuffer [as 别名]
    def encodeInterest(self, interest):
        """
        Encode interest in NDN-TLV and return the encoding.

        :param Interest interest: The Interest object to encode.
        :return: A Tuple of (encoding, signedPortionBeginOffset,
          signedPortionEndOffset) where encoding is a Blob containing the
          encoding, signedPortionBeginOffset is the offset in the encoding of
          the beginning of the signed portion, and signedPortionEndOffset is
          the offset in the encoding of the end of the signed portion. The
          signed portion starts from the first name component and ends just
          before the final name component (which is assumed to be a signature
          for a signed interest).
        :rtype: (Blob, int, int)
        """
        encoder = TlvEncoder(256)
        saveLength = len(encoder)

        # Encode backwards.
        encoder.writeOptionalNonNegativeIntegerTlv(
          Tlv.SelectedDelegation, interest.getSelectedDelegationIndex())
        linkWireEncoding = interest.getLinkWireEncoding(self)
        if not linkWireEncoding.isNull():
          # Encode the entire link as is.
          encoder.writeBuffer(linkWireEncoding.buf())

        encoder.writeOptionalNonNegativeIntegerTlvFromFloat(
          Tlv.InterestLifetime, interest.getInterestLifetimeMilliseconds())

        # Encode the Nonce as 4 bytes.
        if interest.getNonce().size() == 0:
            # This is the most common case. Generate a nonce.
            nonce = bytearray(4)
            for i in range(4):
                nonce[i] = _systemRandom.randint(0, 0xff)
            encoder.writeBlobTlv(Tlv.Nonce, nonce)
        elif interest.getNonce().size() < 4:
            nonce = bytearray(4)
            # Copy existing nonce bytes.
            nonce[:interest.getNonce().size()] = interest.getNonce().buf()

            # Generate random bytes for remaining bytes in the nonce.
            for i in range(interest.getNonce().size(), 4):
                nonce[i] = _systemRandom.randint(0, 0xff)

            encoder.writeBlobTlv(Tlv.Nonce, nonce)
        elif interest.getNonce().size() == 4:
            # Use the nonce as-is.
            encoder.writeBlobTlv(Tlv.Nonce, interest.getNonce().buf())
        else:
            # Truncate.
            encoder.writeBlobTlv(Tlv.Nonce, interest.getNonce().buf()[:4])

        self._encodeSelectors(interest, encoder)

        (tempSignedPortionBeginOffset, tempSignedPortionEndOffset) = \
          self._encodeName(interest.getName(), encoder)
        signedPortionBeginOffsetFromBack = (len(encoder) -
                                            tempSignedPortionBeginOffset)
        signedPortionEndOffsetFromBack = (len(encoder) -
                                          tempSignedPortionEndOffset)

        encoder.writeTypeAndLength(Tlv.Interest, len(encoder) - saveLength)
        signedPortionBeginOffset = (len(encoder) -
                                    signedPortionBeginOffsetFromBack)
        signedPortionEndOffset = len(encoder) - signedPortionEndOffsetFromBack

        return (Blob(encoder.getOutput(), False), signedPortionBeginOffset,
                signedPortionEndOffset)