def deserialize_encryption_context()

in src/aws_encryption_sdk/internal/formatting/encryption_context.py [0:0]

• 25 lines of code
• 6 McCabe index (conditional complexity)

def deserialize_encryption_context(serialized_encryption_context):
    """Deserializes the contents of a byte string into a dictionary.

    :param bytes serialized_encryption_context: Source byte string containing serialized dictionary
    :returns: Deserialized encryption context
    :rtype: dict
    :raises SerializationError: if serialized encryption context is too large
    :raises SerializationError: if duplicate key found in serialized encryption context
    :raises SerializationError: if malformed data found in serialized encryption context
    """
    if len(serialized_encryption_context) > aws_encryption_sdk.internal.defaults.MAX_BYTE_ARRAY_SIZE:
        raise SerializationError("Serialized context is too long.")

    if serialized_encryption_context == b"":
        _LOGGER.debug("No encryption context data found")
        return {}

    deserialized_size = 0
    encryption_context = {}

    dict_size, deserialized_size = read_short(source=serialized_encryption_context, offset=deserialized_size)
    _LOGGER.debug("Found %d keys", dict_size)
    for _ in range(dict_size):
        key_size, deserialized_size = read_short(source=serialized_encryption_context, offset=deserialized_size)
        key, deserialized_size = read_string(
            source=serialized_encryption_context, offset=deserialized_size, length=key_size
        )
        value_size, deserialized_size = read_short(source=serialized_encryption_context, offset=deserialized_size)
        value, deserialized_size = read_string(
            source=serialized_encryption_context, offset=deserialized_size, length=value_size
        )
        if key in encryption_context:
            raise SerializationError("Duplicate key in serialized context.")
        encryption_context[key] = value

    if deserialized_size != len(serialized_encryption_context):
        raise SerializationError("Formatting error: Extra data in serialized context.")

    return encryption_context