Worked on structure group support

Author: joachimmetz

config/dpkg/changelog

@@ -1,5 +1,5 @@
-dtfabric (20230519-1) unstable; urgency=low
+dtfabric (20230520-1) unstable; urgency=low
 
   * Auto-generated
 
- -- Joachim Metz <[email protected]>  Fri, 19 May 2023 04:56:42 +0200
+ -- Joachim Metz <[email protected]>  Sat, 20 May 2023 05:28:59 +0200

docs/sources/Format-specification.md

@@ -537,3 +537,10 @@ members:
 
 The structure group members are required to define the identifier structure
 member with its values specific to the group member.
+
+Attribute name | Attribute type | Required | Description
+--- | --- | --- | ---
+base | string | Yes | Base data type. Note that this must be a structure data type.
+default | string | None | Default data type as fallback if no corresponding member data type is defined. Note that this must be a structure data type.
+identifier | string | Yes | Name of the member in the base (structure) data type that identified a (group) member.
+members | list | Yes | List of (group) member data types. Note that these must be a structure data types.

dtfabric/__init__.py

@@ -1,4 +1,4 @@
 # -*- coding: utf-8 -*-
 """Data type fabric."""
 
-__version__ = '20230519'
+__version__ = '20230520'

dtfabric/data_types.py

@@ -901,6 +901,8 @@ class StructureGroupDefinition(LayoutDataTypeDefinition):
 
   Attributes:
     base (DataTypeDefinition): base data type definition.
+    byte_order (str): byte-order the data type.
+    default (DataTypeDefinition): default data type definition.
     identifier (str): name of the base structure member to identify the group
         members.
     members (list[DataTypeDefinition]): member data type definitions.
@@ -911,7 +913,8 @@ class StructureGroupDefinition(LayoutDataTypeDefinition):
 
   def __init__(
       self, name: 'str', base_definition: 'StructureDefinition',
-      identifier: 'str', aliases: 'Optional[List[str]]' = None,
+      identifier: 'str', default_definition: 'StructureDefinition',
+      aliases: 'Optional[List[str]]' = None,
       description: 'Optional[str]' = None,
       urls: 'Optional[List[str]]' = None) -> 'None':
     """Initializes a structure group data type definition.
@@ -921,6 +924,7 @@ def __init__(
       base_definition (StructureDefinition): base data type definition.
       identifier (str): name of the base structure member to identify the group
           members.
+      default_definition (StructureDefinition): default data type definition.
       aliases (Optional[list[str]]): aliases.
       description (Optional[str]): description.
       urls (Optional[list[str]]): URLs.
@@ -930,6 +934,9 @@ def __init__(
     self._members_by_name: 'OrderedDict[str, DataTypeDefinition]' = (
         collections.OrderedDict())
     self.base: 'Union[DataTypeDefinition, None]' = base_definition
+    self.byte_order: 'str' = getattr(
+        base_definition, 'byte_order', definitions.BYTE_ORDER_NATIVE)
+    self.default: 'Union[DataTypeDefinition, None]' = default_definition
     self.identifier: 'Union[str, None]' = identifier
 
   @property

dtfabric/reader.py

@@ -87,7 +87,7 @@ class DataTypeDefinitionsReader(object):
       'base', 'members']).union(_SUPPORTED_DEFINITION_VALUES_DATA_TYPE)
 
   _SUPPORTED_DEFINITION_VALUES_STRUCTURE_GROUP = set([
-      'base', 'identifier', 'members']).union(
+      'base', 'default', 'identifier', 'members']).union(
           _SUPPORTED_DEFINITION_VALUES_DATA_TYPE)
 
   _SUPPORTED_ATTRIBUTES_STORAGE_DATA_TYPE = set([
@@ -1145,13 +1145,24 @@ def _ReadStructureGroupDataTypeDefinition(
     if not identifier:
       raise errors.DefinitionReaderError(definition_name, 'missing identifier')
 
+    default = definition_values.get('default', None)
+    if not default:
+      default_data_type_definition = None
+    else:
+      default_data_type_definition = definitions_registry.GetDefinitionByName(
+          default)
+      if not default_data_type_definition:
+        raise errors.DefinitionReaderError(definition_name, (
+            f'undefined default: {default:s}'))
+
     aliases = definition_values.get('aliases', None)
     description = definition_values.get('description', None)
     urls = definition_values.get('urls', None)
 
     definition_object = data_types.StructureGroupDefinition(
         definition_name, base_data_type_definition, identifier,
-        aliases=aliases, description=description, urls=urls)
+        default_data_type_definition, aliases=aliases, description=description,
+        urls=urls)
 
     members = definition_values.get('members', None)
     if not members:

dtfabric/runtime/data_maps.py

@@ -2209,10 +2209,16 @@ def __init__(self, data_type_definition):
       FormatError: if the data type map cannot be determined from the data
           type definition.
     """
+    default_data_type_map = None
+    if data_type_definition.default:
+      default_data_type_map = DataTypeMapFactory.CreateDataTypeMapByType(
+          data_type_definition.default)
+
     super(StructureGroupMap, self).__init__(data_type_definition)
     self._base_data_type_map = DataTypeMapFactory.CreateDataTypeMapByType(
         data_type_definition.base)
     self._data_type_maps = None
+    self._default_data_type_map = default_data_type_map
 
     self._GetMemberDataTypeMaps(data_type_definition)
 
@@ -2344,7 +2350,8 @@ def MapByteStream(self, byte_stream, context=None, **kwargs):
 
       context_state['member_identifier'] = member_identifier
 
-    member_data_type_map = self._data_type_maps.get(member_identifier, None)
+    member_data_type_map = self._data_type_maps.get(
+        member_identifier, self._default_data_type_map)
     if member_data_type_map is None:
       raise errors.MappingError(
           f'Missing member data type map for '

tests/data_types.py

@@ -535,7 +535,8 @@ def testInitialize(self):
         'base', description='my base structure type')
 
     data_type_definition = data_types.StructureGroupDefinition(
-        'group', base_definition, 'identifier', description='structure group')
+        'group', base_definition, 'identifier', None,
+        description='structure group')
     self.assertIsNotNone(data_type_definition)
 
   def testAddMemberDefinition(self):
@@ -544,7 +545,8 @@ def testAddMemberDefinition(self):
         'base', description='my base structure type')
 
     data_type_definition = data_types.StructureGroupDefinition(
-        'group', base_definition, 'identifier', description='structure group')
+        'group', base_definition, 'identifier', None,
+        description='structure group')
     self.assertIsNotNone(data_type_definition)
 
     group_member_definition = data_types.StructureDefinition(