dau_driver.stream_codec
=======================

.. py:module:: dau_driver.stream_codec


Attributes
----------

.. autoapisummary::

   dau_driver.stream_codec._ALIGNMENT_BYTES
   dau_driver.stream_codec._SCALAR_RESULT_STRUCTS
   dau_driver.stream_codec._STRUCT_CODES
   dau_driver.stream_codec._ARROW_TYPE_FACTORIES


Classes
-------

.. autoapisummary::

   dau_driver.stream_codec.DecodedStreamColumn
   dau_driver.stream_codec.DecodedStreamResult
   dau_driver.stream_codec.RecordBatchColumn
   dau_driver.stream_codec.DecodedRecordBatch
   dau_driver.stream_codec.StreamEncoder
   dau_driver.stream_codec.StreamDecoder


Functions
---------

.. autoapisummary::

   dau_driver.stream_codec._arrow_to_logical_type
   dau_driver.stream_codec._logical_to_arrow_type
   dau_driver.stream_codec._validate_header
   dau_driver.stream_codec._validate_column
   dau_driver.stream_codec._validate_operations
   dau_driver.stream_codec._validate_payload_window
   dau_driver.stream_codec._normalize_supported_type
   dau_driver.stream_codec._normalize_operation_descriptor
   dau_driver.stream_codec._unpack_column
   dau_driver.stream_codec._unpack_operation
   dau_driver.stream_codec._align_up


Module Contents
---------------

.. py:data:: _ALIGNMENT_BYTES
   :value: 64


.. py:data:: _SCALAR_RESULT_STRUCTS

.. py:data:: _STRUCT_CODES

.. py:function:: _arrow_to_logical_type(arrow_type) -> dau_core.stream.LogicalType

.. py:function:: _logical_to_arrow_type(logical_type: dau_core.stream.LogicalType)

.. py:data:: _ARROW_TYPE_FACTORIES

.. py:class:: DecodedStreamColumn

   .. py:attribute:: header
      :type:  dau_core.stream.BatchHeader


   .. py:attribute:: column
      :type:  dau_core.stream.ColumnDescriptor


   .. py:attribute:: payload
      :type:  bytes


   .. py:attribute:: operations
      :type:  tuple[dau_core.stream.OperationDescriptor, ...]
      :value: ()



.. py:class:: DecodedStreamResult

   .. py:attribute:: header
      :type:  dau_core.stream.BatchHeader


   .. py:attribute:: column
      :type:  dau_core.stream.ColumnDescriptor


   .. py:attribute:: payload
      :type:  bytes


   .. py:attribute:: value
      :type:  int | float


.. py:class:: RecordBatchColumn

   One fixed-width, null-free input column for record-batch encoding.


   .. py:attribute:: field_id
      :type:  int


   .. py:attribute:: logical_type
      :type:  dau_core.stream.LogicalType


   .. py:attribute:: payload
      :type:  bytes


.. py:class:: DecodedRecordBatch

   .. py:attribute:: header
      :type:  dau_core.stream.BatchHeader


   .. py:attribute:: columns
      :type:  tuple[dau_core.stream.ColumnDescriptor, ...]


   .. py:attribute:: payloads
      :type:  tuple[bytes, ...]


   .. py:attribute:: operations
      :type:  tuple[dau_core.stream.OperationDescriptor, ...]
      :value: ()



   .. py:method:: column_payload(field_id: int) -> bytes


.. py:class:: StreamEncoder

   .. py:method:: encode_column(logical_type: dau_core.stream.LogicalType, payload: bytes, *, row_count: int, field_id: int = 0, schema_hash: int = 0, batch_id: int = 0, operations: collections.abc.Iterable[dau_core.stream.OperationDescriptor] = ()) -> bytes
      :staticmethod:



   .. py:method:: encode_record_batch(columns: collections.abc.Sequence[RecordBatchColumn], *, row_count: int, schema_hash: int = 0, batch_id: int = 0, operations: collections.abc.Iterable[dau_core.stream.OperationDescriptor] = (), limits: dau_core.stream.RecordBatchLimits = DEFAULT_RECORD_BATCH_LIMITS) -> bytes
      :staticmethod:


      Encode N fixed-width, null-free columns as one multi-column batch.



   .. py:method:: encode_arrow_batch(batch, *, schema_hash: int = 0, batch_id: int = 0, operations: collections.abc.Iterable[dau_core.stream.OperationDescriptor] = (), limits: dau_core.stream.RecordBatchLimits = DEFAULT_RECORD_BATCH_LIMITS) -> bytes
      :staticmethod:


      Encode a PyArrow ``RecordBatch``/``Table`` of fixed-width, null-free columns.



.. py:class:: StreamDecoder

   .. py:method:: decode_column(data: bytes) -> DecodedStreamColumn
      :staticmethod:



   .. py:method:: decode_record_batch(data: bytes, *, limits: dau_core.stream.RecordBatchLimits = DEFAULT_RECORD_BATCH_LIMITS) -> DecodedRecordBatch
      :staticmethod:


      Decode a multi-column record batch (the N-column counterpart of decode_column).



   .. py:method:: decode_record_batch_to_arrow(data: bytes, *, names: collections.abc.Sequence[str] | None = None, limits: dau_core.stream.RecordBatchLimits = DEFAULT_RECORD_BATCH_LIMITS)
      :staticmethod:


      Decode and rematerialize as a PyArrow ``RecordBatch``.



   .. py:method:: decode_scalar_result(data: bytes) -> DecodedStreamResult
      :staticmethod:



.. py:function:: _validate_header(header: dau_core.stream.BatchHeader, encoded_length: int) -> None

.. py:function:: _validate_column(header: dau_core.stream.BatchHeader, column: dau_core.stream.ColumnDescriptor, encoded_length: int) -> None

.. py:function:: _validate_operations(header: dau_core.stream.BatchHeader, operations: tuple[dau_core.stream.OperationDescriptor, ...]) -> None

.. py:function:: _validate_payload_window(payload_offset: int, payload_length: int, encoded_length: int) -> None

.. py:function:: _normalize_supported_type(logical_type: dau_core.stream.LogicalType) -> dau_core.stream.LogicalType

.. py:function:: _normalize_operation_descriptor(operation: dau_core.stream.OperationDescriptor, *, column_count: int = 1) -> dau_core.stream.OperationDescriptor

.. py:function:: _unpack_column(data: bytes) -> dau_core.stream.ColumnDescriptor

.. py:function:: _unpack_operation(data: bytes) -> dau_core.stream.OperationDescriptor

.. py:function:: _align_up(value: int, alignment: int) -> int