.. index:: single: ccsds_time_fields
.. _ccsds_time_fields/0:

.. rst-class:: right

**object**

``ccsds_time_fields``
=====================

Helpers for parsing and generating self-describing CCSDS time fields using descriptor terms and the existing CCSDS time-code objects.

| **Availability:** 
|    ``logtalk_load(ccsds_time_fields(loader))``

| **Author:** Paulo Moura
| **Version:** 1:0:0
| **Date:** 2026-05-09

| **Compilation flags:**
|    ``static, context_switching_calls``


| **Uses:**
|    :ref:`reader <reader/0>`
|    :ref:`type <type/0>`

| **Remarks:**
|    (none)

| **Inherited public predicates:**
|    (none)

.. contents::
   :local:
   :backlinks: top

Public predicates
-----------------

.. index:: valid_descriptor/1
.. _ccsds_time_fields/0::valid_descriptor/1:

``valid_descriptor/1``
^^^^^^^^^^^^^^^^^^^^^^

True if the argument is a supported CCSDS time-field descriptor term.

| **Compilation flags:**
|    ``static``

| **Template:**
|    ``valid_descriptor(Descriptor)``
| **Mode and number of proofs:**
|    ``valid_descriptor(@compound)`` - ``zero_or_one``


------------

.. index:: parse/3
.. _ccsds_time_fields/0::parse/3:

``parse/3``
^^^^^^^^^^^

Parses a self-describing CCSDS time field from a source term into a descriptor term and a time-code term. Supported source terms are ``file(File)``, ``stream(Stream)``, and ``bytes(Bytes)``.

| **Compilation flags:**
|    ``static``

| **Template:**
|    ``parse(Source,Descriptor,TimeCode)``
| **Mode and number of proofs:**
|    ``parse(+compound,?compound,-compound)`` - ``one_or_error``

| **Exceptions:**
|    ``Source`` is a variable:
|        ``instantiation_error``
|    ``Source`` is neither a variable nor a valid source:
|        ``domain_error(ccsds_time_field_source,Source)``
|    ``Source`` contents are not a supported CCSDS time field:
|        ``domain_error(ccsds_time_field_byte_sequence,Bytes)``


------------

.. index:: generate/3
.. _ccsds_time_fields/0::generate/3:

``generate/3``
^^^^^^^^^^^^^^

Generates a self-describing CCSDS time field to a sink term from a descriptor term and a time-code term. Supported sink terms are ``file(File)``, ``stream(Stream)``, and ``bytes(Bytes)``.

| **Compilation flags:**
|    ``static``

| **Template:**
|    ``generate(Sink,Descriptor,TimeCode)``
| **Mode and number of proofs:**
|    ``generate(+compound,+compound,+compound)`` - ``one_or_error``

| **Exceptions:**
|    ``Sink`` is a variable:
|        ``instantiation_error``
|    ``Descriptor`` is a variable:
|        ``instantiation_error``
|    ``TimeCode`` is a variable:
|        ``instantiation_error``
|    ``Sink`` is neither a variable nor a valid sink:
|        ``domain_error(ccsds_time_field_sink,Sink)``
|    ``Descriptor`` is neither a variable nor a supported descriptor term:
|        ``domain_error(ccsds_time_field_descriptor,Descriptor)``
|    ``TimeCode`` is neither a variable nor a valid time code term for the selected descriptor:
|        ``domain_error(ccsds_time_code_term,TimeCode)``


------------

.. index:: format/2
.. _ccsds_time_fields/0::format/2:

``format/2``
^^^^^^^^^^^^

Returns the CCSDS time-code format selected by a descriptor term.

| **Compilation flags:**
|    ``static``

| **Template:**
|    ``format(Descriptor,Format)``
| **Mode and number of proofs:**
|    ``format(+compound,-atom)`` - ``one_or_error``


------------

.. index:: epoch/2
.. _ccsds_time_fields/0::epoch/2:

``epoch/2``
^^^^^^^^^^^

Returns the epoch selected by a descriptor term. Calendar segmented descriptors return ``none``.

| **Compilation flags:**
|    ``static``

| **Template:**
|    ``epoch(Descriptor,Epoch)``
| **Mode and number of proofs:**
|    ``epoch(+compound,-atom)`` - ``one_or_error``


------------

Protected predicates
--------------------

(no local declarations; see entity ancestors if any)

Private predicates
------------------

(no local declarations; see entity ancestors if any)

Operators
---------

(none)