def test_uncompress_exact_len_err(self):
data = six.binary_type(bytearray(range(100)))
zipped = zlib.compress(data)
total = len(zipped)
reader = ExactSizeReader(ZipCompressedReader(six.BytesIO(zipped)))
with self.assertRaises(EOFError):
reader.read(size=total + 1)
def __init__(self, wxf_input):
"""WXF parser returning Python object from a WXF encoded byte sequence.
"""
self.context = SerializationContext()
self.reader = wxf_input_to_buffer(wxf_input)
version, compress = self.parse_header()
if compress == True:
self.reader = ZipCompressedReader(self.reader)
else:
self.reader = ExactSizeReader(self.reader)
def test_uncompress_exact_len(self):
byte_list = [random.randint(0, 255) for i in range(10000)]
data = six.binary_type(bytearray(byte_list))
zipped = zlib.compress(data)
total = len(zipped)
num_of_chunk = 20
chunk_size = total // num_of_chunk
in_buffer = six.BytesIO(zipped)
reader = ExactSizeReader(ZipCompressedReader(in_buffer))
buff = six.BytesIO()
for i in range(num_of_chunk):
buff.write(reader.read(chunk_size))
self.assertEqual(buff.getvalue(), data[:(i + 1) * chunk_size])
buff.write(reader.read())
self.assertEqual(buff.getvalue(), data)
def __init__(self, wxf_input):
"""WXF parser returning Python object from a WXF encoded byte sequence.
"""
self.context = SerializationContext()
if isinstance(wxf_input, (six.binary_type, six.buffer_types)):
self.reader = six.BytesIO(wxf_input)
elif hasattr(wxf_input, 'read'):
self.reader = wxf_input
else:
raise TypeError(
'Class %s neither implements a read method nor is a binary type.'
% wxf_input.__class__.__name__)
version, compress = self.parse_header()
if compress == True:
self.reader = ZipCompressedReader(self.reader)
else:
self.reader = ExactSizeReader(self.reader)
class WXFParser(object):
"""Parse a WXF input.
This class is initialized with a WXF input, and exposes a generator of
:class:`~wolframclient.deserializers.wxf.wxfparser.WXFToken`.
The input `wxf_input` can be a string of bytes with the serialized expression, a string of unicodes
in which case it is considered as a filename, a object implementing a `read` method.
The generator outputs WXF tokens one by one::
with open('/tmp/data.wxf', 'rb') as fp:
parser = WXFParser(fp)
gen = parser.tokens()
print(next(gen))
This low level class is providing intermediary objects to ease the parsing of WXF. Most of
the time one should directly use high level interface such as
:func:`~wolframclient.deserializers.wxf.wxfparser.binary_deserialize`.
The token generator is generally consumed by an instance of
:class:`~wolframclient.deserializers.wxf.wxfconsumer.WXFConsumer`.
"""
_mapping = {
constants.WXF_CONSTANTS.Symbol: "token_for_string",
constants.WXF_CONSTANTS.String: "token_for_string",
constants.WXF_CONSTANTS.BigInteger: "token_for_string",
constants.WXF_CONSTANTS.BigReal: "token_for_string",
constants.WXF_CONSTANTS.Function: "token_for_function",
constants.WXF_CONSTANTS.BinaryString: "token_for_binary_string",
constants.WXF_CONSTANTS.Integer8: "token_for_integer8",
constants.WXF_CONSTANTS.Integer16: "token_for_integer16",
constants.WXF_CONSTANTS.Integer32: "token_for_integer32",
constants.WXF_CONSTANTS.Integer64: "token_for_integer64",
constants.WXF_CONSTANTS.Real64: "token_for_real64",
constants.WXF_CONSTANTS.PackedArray: "token_for_packed_array",
constants.WXF_CONSTANTS.NumericArray: "token_for_numeric_array",
constants.WXF_CONSTANTS.Association: "token_for_association",
constants.WXF_CONSTANTS.Rule: "token_for_rule",
constants.WXF_CONSTANTS.RuleDelayed: "token_for_rule",
}
def __init__(self, wxf_input):
"""WXF parser returning Python object from a WXF encoded byte sequence.
"""
self.context = SerializationContext()
self.reader = wxf_input_to_buffer(wxf_input)
version, compress = self.parse_header()
if compress == True:
self.reader = ZipCompressedReader(self.reader)
else:
self.reader = ExactSizeReader(self.reader)
def tokens(self):
"""Generate instances :class:`~wolframclient.deserializers.wxf.wxfparser.WXFToken` from a WXF input."""
yield self.next_token()
while not self.context.is_valid_final_state():
yield self.next_token()
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 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 token_for_string(self, token):
self.context.add_part()
token.length = parse_varint(self.reader)
if token.length == 0:
token.data = ""
else:
token.data = self.reader.read(token.length).decode("utf8")
return token
def token_for_integer8(self, token):
self.context.add_part()
token.data = constants.StructInt8LE.unpack(self.reader.read(1))[0]
return token
def token_for_integer16(self, token):
self.context.add_part()
token.data = constants.StructInt16LE.unpack(self.reader.read(2))[0]
return token
def token_for_integer32(self, token):
self.context.add_part()
token.data = constants.StructInt32LE.unpack(self.reader.read(4))[0]
return token
def token_for_integer64(self, token):
self.context.add_part()
token.data = constants.StructInt64LE.unpack(self.reader.read(8))[0]
return token
def token_for_real64(self, token):
self.context.add_part()
token.data = constants.StructDouble.unpack(self.reader.read(8))[0]
return token
def token_for_function(self, token):
token.length = parse_varint(self.reader)
self.context.step_into_new_function(token.length)
return token
def token_for_association(self, token):
token.length = parse_varint(self.reader)
self.context.step_into_new_assoc(token.length)
return token
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 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 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_binary_string(self, token):
self.context.add_part()
token.length = parse_varint(self.reader)
if token.length == 0:
token.data = b""
else:
token.data = self.reader.read(token.length)
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))
