.. _data.file:

SPEC Data File
--------------

The SPEC data file is written to a NeXus HDF5 file by parts as described below.

.. _data.file.name:

File name
+++++++++

The file name (shown in this example):

.. code-block::
   :linenos:

   #F /home/sricat/POLAR/data/CMR/lmn40.spe

The file name is copied to the file root as the ``SPEC_file`` attribute
(denoted here as ``@SPEC_file``):

.. code-block::
   :linenos:

   @SPEC_file = "/home/sricat/POLAR/data/CMR/lmn40.spe"

It is expected there is only one ``#F`` control line in a SPEC data file
(assumes that the name of a file will not change midway) and, if it appears, it
is the first line.

.. _data.file.header:

File header
+++++++++++

Some content from a SPEC data file header is written to the root of the NeXus
HDF5 file.  Consider this example:

.. code-block::
   :linenos:

   #E 918630612
   #D Wed Feb 10 01:10:12 1999
   #C spec1ID  User = polar
   #O0    Theta  Two Theta  sample x  sample y

From this example, this content is written to attributes of the file root:

.. code-block::
   :linenos:

   @SPEC_epoch = 918630612
   @SPEC_date = "1999-02-10T01:10:12"
   @SPEC_comments = "spec1ID  User = polar"
   @SPEC_user = "polar"
   @SPEC_num_headers = 1

The ``@SPEC_comments`` attribute includes contents of *all* ``#C`` (comment)
lines that appear in the header section(s), joined together by newline (``\n``)
characters. See :ref:`data.file.comments` for how this handled in scans.

The additional information in the positioner names ``#O0`` control line will be
used later (in :ref:`data.file.positioners`) when writing the positioners to the
file.