def parse_array(self, token):
# Parsing array rank and dimensions
rank = parse_varint(self.reader)
if rank == 0:
raise WolframParserException("Array rank cannot be zero.")
token.dimensions = []
for i in range(rank):
dim = parse_varint(self.reader)
if dim == 0:
raise WolframParserException("Array dimensions cannot be zero.")
token.dimensions.append(dim)
# reading values
bytecount = constants.ARRAY_TYPES_ELEM_SIZE[token.array_type] * token.element_count
token.data = self.reader.read(bytecount)
def parse_header(self):
compress = False
next_byte = self.reader.read(1)
if next_byte == WXF_VERSION:
version = int(next_byte)
next_byte = self.reader.read(1)
else:
raise WolframParserException("Invalid version %s." % next_byte)
if next_byte == WXF_HEADER_COMPRESS:
compress = True
next_byte = self.reader.read(1)
if next_byte != WXF_HEADER_SEPARATOR:
raise WolframParserException(
"Invalid header. Failed to find header separator ':'.")
return (version, compress)
def consume_bigint(self, current_token, tokens, **kwargs):
"""Consume a :class:`~wolframclient.deserializers.wxf.wxfparser.WXFToken` of type *big integer* as a :class:`int`."""
try:
return int(current_token.data)
except ValueError:
raise WolframParserException("Invalid big integer value: %s" %
current_token.data)
def parse_varint(reader):
"""Parse a readable binary buffer for a positive varint encoded integer."""
count = 0
continuation = True
shift = 0
length = 0
# when we read from stream we get a sequence of bytes. Its length is 1
# except if we reached EOF in which case taking index 0 raises IndexError.
try:
while continuation and count < 8:
count += 1
next_byte = reader.read(1)
next_byte = ord(next_byte)
length |= (next_byte & 0x7F) << shift
shift = shift + 7
continuation = (next_byte & 0x80) != 0
if continuation:
next_byte = reader.read(1)
next_byte = ord(next_byte)
next_byte &= 0x7F
if next_byte == 0:
raise WolframParserException("Invalid last varint byte.")
length |= next_byte << shift
return length
except IndexError:
raise EOFError("EOF reached while parsing varint encoded integer.")
def token_for_rule(self, token):
if not self.context.is_rule_valid():
raise WolframParserException(
"Rule and RuleDelayed must be parts of an Association."
)
self.context.step_into_new_rule()
return token
def _consumer_from_type(self, wxf_type):
try:
func = self._mapping[wxf_type]
except KeyError:
raise WolframParserException(
"Class %s does not implement any consumer method for WXF token %s"
% (self.__class__.__name__, wxf_type))
return getattr(self, func)
def token_for_numeric_array(self, token):
self.context.add_part()
token.array_type = self.reader.read(1)
if token.array_type not in constants.ARRAY_TYPES_ELEM_SIZE:
raise WolframParserException(
"Invalid NumericArray value type: %s" % token.array_type)
self.parse_array(token)
return token
def token_for_packed_array(self, token):
self.context.add_part()
token.array_type = self.reader.read(1)
if token.array_type not in constants.VALID_PACKED_ARRAY_TYPES:
raise WolframParserException("Invalid PackedArray value type: %s" %
token.array_type)
self.parse_array(token)
return token
def next_token(self):
next_byte = self.reader.read(1)
try:
handler = self._mapping[next_byte]
except KeyError:
raise WolframParserException("Unexpected token %s" % next_byte)
return getattr(self, handler)(WXFToken(next_byte))
def binary_deserialize(wxf_input, consumer=None, **kwargs):
"""Deserialize binary data and return a Python object.
Serialize a Python object to WXF::
>>> wxf = export({'key' : [1,2,3]}, target_format='wxf')
Retrieve the input object::
>>> binary_deserialize(wxf)
{'key': [1, 2, 3]}
A stream of :class:`~wolframclient.deserializers.wxf.wxfparser.WXFToken` is generated from the WXF input by a instance
of :class:`~wolframclient.deserializers.wxf.wxfparser.WXFParser`.
The consumer must be an instance of :class:`~wolframclient.deserializers.wxf.wxfconsumer.WXFConsumer`. If none is
provided, :class:`~wolframclient.deserializers.wxf.wxfconsumer.WXFConsumer` is used. To enable NumPy array support,
use :class:`~wolframclient.deserializers.wxf.wxfconsumer.WXFConsumerNumpy`.
Named parameters are passed to the consumer. They can be any valid parameter of
:meth:`~wolframclient.deserializers.wxf.wxfconsumer.WXFConsumer.next_expression`, namely:
* `dict_class`: map WXF `Association` to `dict_class` in place of a regular :class:`dict`
"""
parser = WXFParser(wxf_input)
if consumer is None:
consumer = WXFConsumer()
try:
o = consumer.next_expression(parser.tokens(), **kwargs)
except StopIteration:
raise WolframParserException(
'Input data does not represent a valid expression in WXF format. Expecting more input data.'
)
if not parser.context.is_valid_final_state():
raise WolframParserException(
'Input data does not represent a valid expression in WXF format. Some expressions are incomplete.'
)
return o
def consume_bigreal(self, current_token, tokens, **kwargs):
"""Parse a WXF big real as a WXF serializable big real.
There is not such thing as a big real, in Wolfram Language notation, in Python. This
wrapper ensures round tripping of big reals without the need of `ToExpression`.
Introducing `ToExpression` would imply to marshall the big real data to avoid malicious
code from being introduced in place of an actual real.
"""
match = self.BIGREAL_RE.match(current_token.data)
if match:
num, _, _, exp = match.groups()
if exp:
return decimal.Decimal("%se%s" % (num, exp))
return decimal.Decimal(num)
raise WolframParserException("Invalid big real value: %s" % current_token.data)
