def _GetByteStreamOperation(self, data_type_definition):
"""Retrieves the byte stream operation.
Args:
data_type_definition (DataTypeDefinition): data type definition.
Returns:
ByteStreamOperation: byte stream operation or None if unable to determine.
Raises:
FormatError: if the byte stream operation cannot be determed from the
data type definition.
"""
if not data_type_definition:
raise errors.FormatError(u'Missing data type definition')
members = getattr(data_type_definition, u'members', None)
if not members:
raise errors.FormatError(
u'Invalid data type definition missing members')
byte_order_string = self._GetStructByteOrderString(
data_type_definition)
format_string = u''.join([
member_definition.GetStructFormatString()
for member_definition in members
])
format_string = u''.join([byte_order_string, format_string])
return StructOperation(format_string)
def _GetStructFormatString(self, data_type_definition):
"""Retrieves the Python struct format string.
Args:
data_type_definition (DataTypeDefinition): data type definition.
Returns:
str: format string as used by Python struct or None if format string
cannot be determined.
Raises:
FormatError: if the struct format string cannot be determed from
the data type definition.
"""
if not data_type_definition:
raise errors.FormatError(u'Missing data type definition')
error_string = u''
try:
format_string = data_type_definition.GetStructFormatString()
except (AttributeError, TypeError) as exception:
format_string = None
error_string = u' with error: {0!s}'.format(exception)
if not format_string:
raise errors.FormatError(
u'Unable to determine format string{0:s}'.format(error_string))
return format_string
def _CheckCompositeMap(self, data_type_definition):
"""Determines if the data type definition needs a composite map.
Args:
data_type_definition (DataTypeDefinition): structure data type definition.
Returns:
bool: True if a composite map is needed, False otherwise.
Raises:
FormatError: if a composite map is needed cannot be determed from the
data type definition.
"""
if not data_type_definition:
raise errors.FormatError(u'Missing data type definition')
members = getattr(data_type_definition, u'members', None)
if not members:
raise errors.FormatError(
u'Invalid data type definition missing members')
structure_byte_order = data_type_definition.byte_order
is_composite_map = False
last_member_byte_order = definitions.BYTE_ORDER_NATIVE
for member_definition in members:
if isinstance(member_definition,
data_types.StructureMemberDefinition):
member_definition = member_definition.member_data_type_definition
if member_definition.IsComposite():
is_composite_map = True
continue
member_byte_order = member_definition.byte_order
if (structure_byte_order != definitions.BYTE_ORDER_NATIVE
and structure_byte_order != member_byte_order):
raise errors.FormatError((
u'Contficting byte-order definitions in structure: {0:s} and '
u'member: {1:s}').format(data_type_definition.name,
member_definition.name))
last_member_byte_order = member_byte_order
return is_composite_map
def ReadFileObject(self, definitions_registry, file_object):
"""Reads data type definitions from a file-like object into the registry.
Args:
definitions_registry (DataTypeDefinitionsRegistry): data type definitions
registry.
file_object (file): file-like object to read from.
Raises:
FormatError: if the definitions values are missing or if the format is
incorrect.
"""
last_definition_object = None
error_location = None
error_message = None
try:
yaml_generator = yaml.safe_load_all(file_object)
for yaml_definition in yaml_generator:
definition_object = self._ReadDefinition(
definitions_registry, yaml_definition)
if not definition_object:
error_location = self._GetFormatErrorLocation(
yaml_definition, last_definition_object)
error_message = '{0:s} Missing definition object.'.format(
error_location)
raise errors.FormatError(error_message)
definitions_registry.RegisterDefinition(definition_object)
last_definition_object = definition_object
except errors.DefinitionReaderError as exception:
error_message = 'in: {0:s} {1:s}'.format(
exception.name or '<NAMELESS>', exception.message)
raise errors.FormatError(error_message)
except (yaml.reader.ReaderError,
yaml.scanner.ScannerError) as exception:
error_location = self._GetFormatErrorLocation(
{}, last_definition_object)
error_message = '{0:s} {1!s}'.format(error_location, exception)
raise errors.FormatError(error_message)
def _GetMemberDataTypeMaps(self, data_type_definition,
data_type_map_cache):
"""Retrieves the member data type maps.
Args:
data_type_definition (DataTypeDefinition): data type definition.
data_type_map_cache (dict[str, DataTypeMap]): cached data type maps.
Returns:
list[DataTypeMap]: member data type maps.
Raises:
FormatError: if the data type maps cannot be determed from the data
type definition.
"""
if not data_type_definition:
raise errors.FormatError(u'Missing data type definition')
members = getattr(data_type_definition, u'members', None)
if not members:
raise errors.FormatError(
u'Invalid data type definition missing members')
data_type_maps = []
for member_definition in members:
if isinstance(member_definition,
data_types.StructureMemberDefinition):
member_definition = member_definition.member_data_type_definition
if member_definition.name not in data_type_map_cache:
data_type_map = DataTypeMapFactory.CreateDataTypeMapByType(
member_definition)
data_type_map_cache[member_definition.name] = data_type_map
data_type_maps.append(data_type_map_cache[member_definition.name])
return data_type_maps
def _GetElementDataTypeDefinition(self, data_type_definition):
"""Retrieves the element data type definition.
Args:
data_type_definition (DataTypeDefinition): data type definition.
Returns:
DataTypeDefinition: element data type definition.
Raises:
FormatError: if the data type map cannot be determed from the data
type definition.
"""
if not data_type_definition:
raise errors.FormatError(u'Missing data type definition')
element_data_type_definition = getattr(
data_type_definition, u'element_data_type_definition', None)
if not element_data_type_definition:
raise errors.FormatError(
u'Invalid data type definition missing element')
return element_data_type_definition
def ReadFileObject(self, definitions_registry, file_object):
"""Reads data type definitions from a file-like object into the registry.
Args:
definitions_registry (DataTypeDefinitionsRegistry): data type definitions
registry.
file_object (file): file-like object to read from.
Raises:
FormatError: if the definitions values are missing or if the format is
incorrect.
"""
yaml_generator = yaml.safe_load_all(file_object)
last_definition_object = None
error_location = None
error_message = None
for yaml_definition in yaml_generator:
try:
definition_object = self.ReadDefinitionFromDict(
definitions_registry, yaml_definition)
except errors.DefinitionReaderError as exception:
definition_object = None
if exception.name:
error_location = u'In: {0:s}'.format(exception.name)
error_message = u''.join(exception.message)
if not definition_object:
if not error_location:
name = yaml_definition.get(u'name', None)
if name:
error_location = u'In: {0:s}'.format(name)
elif last_definition_object:
error_location = u'After: {0:s}'.format(
last_definition_object.name)
else:
error_location = u'At start'
if not error_message:
error_message = u'Missing definition object.'
error_message = u'{0:s} {1:s}'.format(error_location,
error_message)
raise errors.FormatError(error_message)
definitions_registry.RegisterDefinition(definition_object)
last_definition_object = definition_object
def __init__(self, data_type_definition):
"""Initializes a data type map.
Args:
data_type_definition (DataTypeDefinition): data type definition.
Raises:
FormatError: if the data type map cannot be determed from the data
type definition.
"""
if (data_type_definition.false_value is None
and data_type_definition.true_value is None):
raise errors.FormatError(
u'Boolean data type has no True or False values.')
super(BooleanMap, self).__init__(data_type_definition)
def __init__(self, format_string):
"""Initializes a Python struct-base byte stream operation.
Args:
format_string (str): format string as used by Python struct.
Raises:
FormatError: if the struct operation cannot be determed from the data
type definition.
"""
try:
struct_object = struct.Struct(format_string)
except (TypeError, struct.error) as exception:
raise errors.FormatError(
(u'Unable to create struct object from data type definition '
u'with error: {0!s}').format(exception))
super(StructOperation, self).__init__()
self._struct = struct_object
self._struct_format_string = format_string
