cpython/pickle.py at 3.9 · python/cpython

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PickleError Class PicklingError Class UnpicklingError Class _Stop Class init Function _Framer Class init Function start_framing Function end_framing Function commit_frame Function write Function write_large_bytes Function _Unframer Class init Function readinto Function read Function readline Function load_frame Function _getattribute Function whichmodule Function encode_long Function decode_long Function _Pickler Class init Function clear_memo Function dump Function memoize Function put Function get Function save Function persistent_id Function save_pers Function save_reduce Function save_none Function save_bool Function save_long Function save_float Function save_bytes Function save_bytearray Function save_picklebuffer Function save_str Function save_tuple Function save_list Function _batch_appends Function save_dict Function _batch_setitems Function save_set Function save_frozenset Function save_global Function save_type Function _Unpickler Class init Function load Function pop_mark Function persistent_load Function load_proto Function load_frame Function load_persid Function load_binpersid Function load_none Function load_false Function load_true Function load_int Function load_binint Function load_binint1 Function load_binint2 Function load_long Function load_long1 Function load_long4 Function load_float Function load_binfloat Function _decode_string Function load_string Function load_binstring Function load_binbytes Function load_unicode Function load_binunicode Function load_binunicode8 Function load_binbytes8 Function load_bytearray8 Function load_next_buffer Function load_readonly_buffer Function load_short_binstring Function load_short_binbytes Function load_short_binunicode Function load_tuple Function load_empty_tuple Function load_tuple1 Function load_tuple2 Function load_tuple3 Function load_empty_list Function load_empty_dictionary Function load_empty_set Function load_frozenset Function load_list Function load_dict Function _instantiate Function load_inst Function load_obj Function load_newobj Function load_newobj_ex Function load_global Function load_stack_global Function load_ext1 Function load_ext2 Function load_ext4 Function get_extension Function find_class Function load_reduce Function load_pop Function load_pop_mark Function load_dup Function load_get Function load_binget Function load_long_binget Function load_put Function load_binput Function load_long_binput Function load_memoize Function load_append Function load_appends Function load_setitem Function load_setitems Function load_additems Function load_build Function load_mark Function load_stop Function _dump Function _dumps Function _load Function _loads Function _test Function

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	"""Create portable serialized representations of Python objects.

	See module copyreg for a mechanism for registering custom picklers.
	See module pickletools source for extensive comments.

	Classes:

	Pickler
	Unpickler

	Functions:

	dump(object, file)
	dumps(object) -> string
	load(file) -> object
	loads(bytes) -> object

	Misc variables:

	__version__
	format_version
	compatible_formats

	"""

	from types import FunctionType
	from copyreg import dispatch_table
	from copyreg import _extension_registry, _inverted_registry, _extension_cache
	from itertools import islice
	from functools import partial
	import sys
	from sys import maxsize
	from struct import pack, unpack
	import re
	import io
	import codecs
	import _compat_pickle

	__all__ = ["PickleError", "PicklingError", "UnpicklingError", "Pickler",
	"Unpickler", "dump", "dumps", "load", "loads"]

	try:
	from _pickle import PickleBuffer
	__all__.append("PickleBuffer")
	_HAVE_PICKLE_BUFFER = True
	except ImportError:
	_HAVE_PICKLE_BUFFER = False


	# Shortcut for use in isinstance testing
	bytes_types = (bytes, bytearray)

	# These are purely informational; no code uses these.
	format_version = "4.0" # File format version we write
	compatible_formats = ["1.0", # Original protocol 0
	"1.1", # Protocol 0 with INST added
	"1.2", # Original protocol 1
	"1.3", # Protocol 1 with BINFLOAT added
	"2.0", # Protocol 2
	"3.0", # Protocol 3
	"4.0", # Protocol 4
	"5.0", # Protocol 5
	] # Old format versions we can read

	# This is the highest protocol number we know how to read.
	HIGHEST_PROTOCOL = 5

	# The protocol we write by default. May be less than HIGHEST_PROTOCOL.
	# Only bump this if the oldest still supported version of Python already
	# includes it.
	DEFAULT_PROTOCOL = 4

	class PickleError(Exception):
	"""A common base class for the other pickling exceptions."""
	pass

	class PicklingError(PickleError):
	"""This exception is raised when an unpicklable object is passed to the
	dump() method.

	"""
	pass

	class UnpicklingError(PickleError):
	"""This exception is raised when there is a problem unpickling an object,
	such as a security violation.

	Note that other exceptions may also be raised during unpickling, including
	(but not necessarily limited to) AttributeError, EOFError, ImportError,
	and IndexError.

	"""
	pass

	# An instance of _Stop is raised by Unpickler.load_stop() in response to
	# the STOP opcode, passing the object that is the result of unpickling.
	class _Stop(Exception):
	def __init__(self, value):
	self.value = value

	# Jython has PyStringMap; it's a dict subclass with string keys
	try:
	from org.python.core import PyStringMap
	except ImportError:
	PyStringMap = None

	# Pickle opcodes. See pickletools.py for extensive docs. The listing
	# here is in kind-of alphabetical order of 1-character pickle code.
	# pickletools groups them by purpose.

	MARK = b'(' # push special markobject on stack
	STOP = b'.' # every pickle ends with STOP
	POP = b'0' # discard topmost stack item
	POP_MARK = b'1' # discard stack top through topmost markobject
	DUP = b'2' # duplicate top stack item
	FLOAT = b'F' # push float object; decimal string argument
	INT = b'I' # push integer or bool; decimal string argument
	BININT = b'J' # push four-byte signed int
	BININT1 = b'K' # push 1-byte unsigned int
	LONG = b'L' # push long; decimal string argument
	BININT2 = b'M' # push 2-byte unsigned int
	NONE = b'N' # push None
	PERSID = b'P' # push persistent object; id is taken from string arg
	BINPERSID = b'Q' # " " " ; " " " " stack
	REDUCE = b'R' # apply callable to argtuple, both on stack
	STRING = b'S' # push string; NL-terminated string argument
	BINSTRING = b'T' # push string; counted binary string argument
	SHORT_BINSTRING= b'U' # " " ; " " " " < 256 bytes
	UNICODE = b'V' # push Unicode string; raw-unicode-escaped'd argument
	BINUNICODE = b'X' # " " " ; counted UTF-8 string argument
	APPEND = b'a' # append stack top to list below it
	BUILD = b'b' # call __setstate__ or __dict__.update()
	GLOBAL = b'c' # push self.find_class(modname, name); 2 string args
	DICT = b'd' # build a dict from stack items
	EMPTY_DICT = b'}' # push empty dict
	APPENDS = b'e' # extend list on stack by topmost stack slice
	GET = b'g' # push item from memo on stack; index is string arg
	BINGET = b'h' # " " " " " " ; " " 1-byte arg
	INST = b'i' # build & push class instance
	LONG_BINGET = b'j' # push item from memo on stack; index is 4-byte arg
	LIST = b'l' # build list from topmost stack items
	EMPTY_LIST = b']' # push empty list
	OBJ = b'o' # build & push class instance
	PUT = b'p' # store stack top in memo; index is string arg
	BINPUT = b'q' # " " " " " ; " " 1-byte arg
	LONG_BINPUT = b'r' # " " " " " ; " " 4-byte arg
	SETITEM = b's' # add key+value pair to dict
	TUPLE = b't' # build tuple from topmost stack items
	EMPTY_TUPLE = b')' # push empty tuple
	SETITEMS = b'u' # modify dict by adding topmost key+value pairs
	BINFLOAT = b'G' # push float; arg is 8-byte float encoding

	TRUE = b'I01\n' # not an opcode; see INT docs in pickletools.py
	FALSE = b'I00\n' # not an opcode; see INT docs in pickletools.py

	# Protocol 2

	PROTO = b'\x80' # identify pickle protocol
	NEWOBJ = b'\x81' # build object by applying cls.__new__ to argtuple
	EXT1 = b'\x82' # push object from extension registry; 1-byte index
	EXT2 = b'\x83' # ditto, but 2-byte index
	EXT4 = b'\x84' # ditto, but 4-byte index
	TUPLE1 = b'\x85' # build 1-tuple from stack top
	TUPLE2 = b'\x86' # build 2-tuple from two topmost stack items
	TUPLE3 = b'\x87' # build 3-tuple from three topmost stack items
	NEWTRUE = b'\x88' # push True
	NEWFALSE = b'\x89' # push False
	LONG1 = b'\x8a' # push long from < 256 bytes
	LONG4 = b'\x8b' # push really big long

	_tuplesize2code = [EMPTY_TUPLE, TUPLE1, TUPLE2, TUPLE3]

	# Protocol 3 (Python 3.x)

	BINBYTES = b'B' # push bytes; counted binary string argument
	SHORT_BINBYTES = b'C' # " " ; " " " " < 256 bytes

	# Protocol 4

	SHORT_BINUNICODE = b'\x8c' # push short string; UTF-8 length < 256 bytes
	BINUNICODE8 = b'\x8d' # push very long string
	BINBYTES8 = b'\x8e' # push very long bytes string
	EMPTY_SET = b'\x8f' # push empty set on the stack
	ADDITEMS = b'\x90' # modify set by adding topmost stack items
	FROZENSET = b'\x91' # build frozenset from topmost stack items
	NEWOBJ_EX = b'\x92' # like NEWOBJ but work with keyword only arguments
	STACK_GLOBAL = b'\x93' # same as GLOBAL but using names on the stacks
	MEMOIZE = b'\x94' # store top of the stack in memo
	FRAME = b'\x95' # indicate the beginning of a new frame

	# Protocol 5

	BYTEARRAY8 = b'\x96' # push bytearray
	NEXT_BUFFER = b'\x97' # push next out-of-band buffer
	READONLY_BUFFER = b'\x98' # make top of stack readonly

	__all__.extend([x for x in dir() if re.match("[A-Z][A-Z0-9_]+$", x)])


	class _Framer:

	_FRAME_SIZE_MIN = 4
	_FRAME_SIZE_TARGET = 64 * 1024

	def __init__(self, file_write):
	self.file_write = file_write
	self.current_frame = None

	def start_framing(self):
	self.current_frame = io.BytesIO()

	def end_framing(self):
	if self.current_frame and self.current_frame.tell() > 0:
	self.commit_frame(force=True)
	self.current_frame = None

	def commit_frame(self, force=False):
	if self.current_frame:
	f = self.current_frame
	if f.tell() >= self._FRAME_SIZE_TARGET or force:
	data = f.getbuffer()
	write = self.file_write
	if len(data) >= self._FRAME_SIZE_MIN:
	# Issue a single call to the write method of the underlying
	# file object for the frame opcode with the size of the
	# frame. The concatenation is expected to be less expensive
	# than issuing an additional call to write.
	write(FRAME + pack("<Q", len(data)))

	# Issue a separate call to write to append the frame
	# contents without concatenation to the above to avoid a
	# memory copy.
	write(data)

	# Start the new frame with a new io.BytesIO instance so that
	# the file object can have delayed access to the previous frame
	# contents via an unreleased memoryview of the previous
	# io.BytesIO instance.
	self.current_frame = io.BytesIO()

	def write(self, data):
	if self.current_frame:
	return self.current_frame.write(data)
	else:
	return self.file_write(data)

	def write_large_bytes(self, header, payload):
	write = self.file_write
	if self.current_frame:
	# Terminate the current frame and flush it to the file.
	self.commit_frame(force=True)

	# Perform direct write of the header and payload of the large binary
	# object. Be careful not to concatenate the header and the payload
	# prior to calling 'write' as we do not want to allocate a large
	# temporary bytes object.
	# We intentionally do not insert a protocol 4 frame opcode to make
	# it possible to optimize file.read calls in the loader.
	write(header)
	write(payload)


	class _Unframer:

	def __init__(self, file_read, file_readline, file_tell=None):
	self.file_read = file_read
	self.file_readline = file_readline
	self.current_frame = None

	def readinto(self, buf):
	if self.current_frame:
	n = self.current_frame.readinto(buf)
	if n == 0 and len(buf) != 0:
	self.current_frame = None
	n = len(buf)
	buf[:] = self.file_read(n)
	return n
	if n < len(buf):
	raise UnpicklingError(
	"pickle exhausted before end of frame")
	return n
	else:
	n = len(buf)
	buf[:] = self.file_read(n)
	return n

	def read(self, n):
	if self.current_frame:
	data = self.current_frame.read(n)
	if not data and n != 0:
	self.current_frame = None
	return self.file_read(n)
	if len(data) < n:
	raise UnpicklingError(
	"pickle exhausted before end of frame")
	return data
	else:
	return self.file_read(n)

	def readline(self):
	if self.current_frame:
	data = self.current_frame.readline()
	if not data:
	self.current_frame = None
	return self.file_readline()
	if data[-1] != b'\n'[0]:
	raise UnpicklingError(
	"pickle exhausted before end of frame")
	return data
	else:
	return self.file_readline()

	def load_frame(self, frame_size):
	if self.current_frame and self.current_frame.read() != b'':
	raise UnpicklingError(
	"beginning of a new frame before end of current frame")
	self.current_frame = io.BytesIO(self.file_read(frame_size))


	# Tools used for pickling.

	def _getattribute(obj, name):
	for subpath in name.split('.'):
	if subpath == '<locals>':
	raise AttributeError("Can't get local attribute {!r} on {!r}"
	.format(name, obj))
	try:
	parent = obj
	obj = getattr(obj, subpath)
	except AttributeError:
	raise AttributeError("Can't get attribute {!r} on {!r}"
	.format(name, obj)) from None
	return obj, parent

	def whichmodule(obj, name):
	"""Find the module an object belong to."""
	module_name = getattr(obj, '__module__', None)
	if module_name is not None:
	return module_name
	# Protect the iteration by using a list copy of sys.modules against dynamic
	# modules that trigger imports of other modules upon calls to getattr.
	for module_name, module in sys.modules.copy().items():
	if (module_name == '__main__'
	or module_name == '__mp_main__' # bpo-42406
	or module is None):
	continue
	try:
	if _getattribute(module, name)[0] is obj:
	return module_name
	except AttributeError:
	pass
	return '__main__'

	def encode_long(x):
	r"""Encode a long to a two's complement little-endian binary string.
	Note that 0 is a special case, returning an empty string, to save a
	byte in the LONG1 pickling context.

	>>> encode_long(0)
	b''
	>>> encode_long(255)
	b'\xff\x00'
	>>> encode_long(32767)
	b'\xff\x7f'
	>>> encode_long(-256)
	b'\x00\xff'
	>>> encode_long(-32768)
	b'\x00\x80'
	>>> encode_long(-128)
	b'\x80'
	>>> encode_long(127)
	b'\x7f'
	>>>
	"""
	if x == 0:
	return b''
	nbytes = (x.bit_length() >> 3) + 1
	result = x.to_bytes(nbytes, byteorder='little', signed=True)
	if x < 0 and nbytes > 1:
	if result[-1] == 0xff and (result[-2] & 0x80) != 0:
	result = result[:-1]
	return result

	def decode_long(data):
	r"""Decode a long from a two's complement little-endian binary string.

	>>> decode_long(b'')
	0
	>>> decode_long(b"\xff\x00")
	255
	>>> decode_long(b"\xff\x7f")
	32767
	>>> decode_long(b"\x00\xff")
	-256
	>>> decode_long(b"\x00\x80")
	-32768
	>>> decode_long(b"\x80")
	-128
	>>> decode_long(b"\x7f")
	127
	"""
	return int.from_bytes(data, byteorder='little', signed=True)


	# Pickling machinery

	class _Pickler:

	def __init__(self, file, protocol=None, *, fix_imports=True,
	buffer_callback=None):
	"""This takes a binary file for writing a pickle data stream.

	The optional protocol argument tells the pickler to use the
	given protocol; supported protocols are 0, 1, 2, 3, 4 and 5.
	The default protocol is 4. It was introduced in Python 3.4, and
	is incompatible with previous versions.

	Specifying a negative protocol version selects the highest
	protocol version supported. The higher the protocol used, the
	more recent the version of Python needed to read the pickle
	produced.

	The file argument must have a write() method that accepts a
	single bytes argument. It can thus be a file object opened for
	binary writing, an io.BytesIO instance, or any other custom
	object that meets this interface.

	If fix_imports is True and protocol is less than 3, pickle
	will try to map the new Python 3 names to the old module names
	used in Python 2, so that the pickle data stream is readable
	with Python 2.

	If buffer_callback is None (the default), buffer views are
	serialized into file as part of the pickle stream.

	If buffer_callback is not None, then it can be called any number
	of times with a buffer view. If the callback returns a false value
	(such as None), the given buffer is out-of-band; otherwise the
	buffer is serialized in-band, i.e. inside the pickle stream.

	It is an error if buffer_callback is not None and protocol
	is None or smaller than 5.
	"""
	if protocol is None:
	protocol = DEFAULT_PROTOCOL
	if protocol < 0:
	protocol = HIGHEST_PROTOCOL
	elif not 0 <= protocol <= HIGHEST_PROTOCOL:
	raise ValueError("pickle protocol must be <= %d" % HIGHEST_PROTOCOL)
	if buffer_callback is not None and protocol < 5:
	raise ValueError("buffer_callback needs protocol >= 5")
	self._buffer_callback = buffer_callback
	try:
	self._file_write = file.write
	except AttributeError:
	raise TypeError("file must have a 'write' attribute")
	self.framer = _Framer(self._file_write)
	self.write = self.framer.write
	self._write_large_bytes = self.framer.write_large_bytes
	self.memo = {}
	self.proto = int(protocol)
	self.bin = protocol >= 1
	self.fast = 0
	self.fix_imports = fix_imports and protocol < 3

	def clear_memo(self):
	"""Clears the pickler's "memo".

	The memo is the data structure that remembers which objects the
	pickler has already seen, so that shared or recursive objects
	are pickled by reference and not by value. This method is
	useful when re-using picklers.
	"""
	self.memo.clear()

	def dump(self, obj):
	"""Write a pickled representation of obj to the open file."""
	# Check whether Pickler was initialized correctly. This is
	# only needed to mimic the behavior of _pickle.Pickler.dump().
	if not hasattr(self, "_file_write"):
	raise PicklingError("Pickler.__init__() was not called by "
	"%s.__init__()" % (self.__class__.__name__,))
	if self.proto >= 2:
	self.write(PROTO + pack("<B", self.proto))
	if self.proto >= 4:
	self.framer.start_framing()
	self.save(obj)
	self.write(STOP)
	self.framer.end_framing()

	def memoize(self, obj):
	"""Store an object in the memo."""

	# The Pickler memo is a dictionary mapping object ids to 2-tuples
	# that contain the Unpickler memo key and the object being memoized.
	# The memo key is written to the pickle and will become
	# the key in the Unpickler's memo. The object is stored in the
	# Pickler memo so that transient objects are kept alive during
	# pickling.

	# The use of the Unpickler memo length as the memo key is just a
	# convention. The only requirement is that the memo values be unique.
	# But there appears no advantage to any other scheme, and this
	# scheme allows the Unpickler memo to be implemented as a plain (but
	# growable) array, indexed by memo key.
	if self.fast:
	return
	assert id(obj) not in self.memo
	idx = len(self.memo)
	self.write(self.put(idx))
	self.memo[id(obj)] = idx, obj

	# Return a PUT (BINPUT, LONG_BINPUT) opcode string, with argument i.
	def put(self, idx):
	if self.proto >= 4:
	return MEMOIZE
	elif self.bin:
	if idx < 256:
	return BINPUT + pack("<B", idx)
	else:
	return LONG_BINPUT + pack("<I", idx)
	else:
	return PUT + repr(idx).encode("ascii") + b'\n'

	# Return a GET (BINGET, LONG_BINGET) opcode string, with argument i.
	def get(self, i):
	if self.bin:
	if i < 256:
	return BINGET + pack("<B", i)
	else:
	return LONG_BINGET + pack("<I", i)

	return GET + repr(i).encode("ascii") + b'\n'

	def save(self, obj, save_persistent_id=True):
	self.framer.commit_frame()

	# Check for persistent id (defined by a subclass)
	pid = self.persistent_id(obj)
	if pid is not None and save_persistent_id:
	self.save_pers(pid)
	return

	# Check the memo
	x = self.memo.get(id(obj))
	if x is not None:
	self.write(self.get(x[0]))
	return

	rv = NotImplemented
	reduce = getattr(self, "reducer_override", None)
	if reduce is not None:
	rv = reduce(obj)

	if rv is NotImplemented:
	# Check the type dispatch table
	t = type(obj)
	f = self.dispatch.get(t)
	if f is not None:
	f(self, obj) # Call unbound method with explicit self
	return

	# Check private dispatch table if any, or else
	# copyreg.dispatch_table
	reduce = getattr(self, 'dispatch_table', dispatch_table).get(t)
	if reduce is not None:
	rv = reduce(obj)
	else:
	# Check for a class with a custom metaclass; treat as regular
	# class
	if issubclass(t, type):
	self.save_global(obj)
	return

	# Check for a __reduce_ex__ method, fall back to __reduce__
	reduce = getattr(obj, "__reduce_ex__", None)
	if reduce is not None:
	rv = reduce(self.proto)
	else:
	reduce = getattr(obj, "__reduce__", None)
	if reduce is not None:
	rv = reduce()
	else:
	raise PicklingError("Can't pickle %r object: %r" %
	(t.__name__, obj))

	# Check for string returned by reduce(), meaning "save as global"
	if isinstance(rv, str):
	self.save_global(obj, rv)
	return

	# Assert that reduce() returned a tuple
	if not isinstance(rv, tuple):
	raise PicklingError("%s must return string or tuple" % reduce)

	# Assert that it returned an appropriately sized tuple
	l = len(rv)
	if not (2 <= l <= 6):
	raise PicklingError("Tuple returned by %s must have "
	"two to six elements" % reduce)

	# Save the reduce() output and finally memoize the object
	self.save_reduce(obj=obj, *rv)

	def persistent_id(self, obj):
	# This exists so a subclass can override it
	return None

	def save_pers(self, pid):
	# Save a persistent id reference
	if self.bin:
	self.save(pid, save_persistent_id=False)
	self.write(BINPERSID)
	else:
	try:
	self.write(PERSID + str(pid).encode("ascii") + b'\n')
	except UnicodeEncodeError:
	raise PicklingError(
	"persistent IDs in protocol 0 must be ASCII strings")

	def save_reduce(self, func, args, state=None, listitems=None,
	dictitems=None, state_setter=None, obj=None):
	# This API is called by some subclasses

	if not isinstance(args, tuple):
	raise PicklingError("args from save_reduce() must be a tuple")
	if not callable(func):
	raise PicklingError("func from save_reduce() must be callable")

	save = self.save
	write = self.write

	func_name = getattr(func, "__name__", "")
	if self.proto >= 2 and func_name == "__newobj_ex__":
	cls, args, kwargs = args
	if not hasattr(cls, "__new__"):
	raise PicklingError("args[0] from {} args has no __new__"
	.format(func_name))
	if obj is not None and cls is not obj.__class__:
	raise PicklingError("args[0] from {} args has the wrong class"
	.format(func_name))
	if self.proto >= 4:
	save(cls)
	save(args)
	save(kwargs)
	write(NEWOBJ_EX)
	else:
	func = partial(cls.__new__, cls, args, *kwargs)
	save(func)
	save(())
	write(REDUCE)
	elif self.proto >= 2 and func_name == "__newobj__":
	# A __reduce__ implementation can direct protocol 2 or newer to
	# use the more efficient NEWOBJ opcode, while still
	# allowing protocol 0 and 1 to work normally. For this to
	# work, the function returned by __reduce__ should be
	# called __newobj__, and its first argument should be a
	# class. The implementation for __newobj__
	# should be as follows, although pickle has no way to
	# verify this:
	#
	# def __newobj__(cls, *args):
	# return cls.__new__(cls, *args)
	#
	# Protocols 0 and 1 will pickle a reference to __newobj__,
	# while protocol 2 (and above) will pickle a reference to
	# cls, the remaining args tuple, and the NEWOBJ code,
	# which calls cls.__new__(cls, *args) at unpickling time
	# (see load_newobj below). If __reduce__ returns a
	# three-tuple, the state from the third tuple item will be
	# pickled regardless of the protocol, calling __setstate__
	# at unpickling time (see load_build below).
	#
	# Note that no standard __newobj__ implementation exists;
	# you have to provide your own. This is to enforce
	# compatibility with Python 2.2 (pickles written using
	# protocol 0 or 1 in Python 2.3 should be unpicklable by
	# Python 2.2).
	cls = args[0]
	if not hasattr(cls, "__new__"):
	raise PicklingError(
	"args[0] from __newobj__ args has no __new__")
	if obj is not None and cls is not obj.__class__:
	raise PicklingError(
	"args[0] from __newobj__ args has the wrong class")
	args = args[1:]
	save(cls)
	save(args)
	write(NEWOBJ)
	else:
	save(func)
	save(args)
	write(REDUCE)

	if obj is not None:
	# If the object is already in the memo, this means it is
	# recursive. In this case, throw away everything we put on the
	# stack, and fetch the object back from the memo.
	if id(obj) in self.memo:
	write(POP + self.get(self.memo[id(obj)][0]))
	else:
	self.memoize(obj)

	# More new special cases (that work with older protocols as
	# well): when __reduce__ returns a tuple with 4 or 5 items,
	# the 4th and 5th item should be iterators that provide list
	# items and dict items (as (key, value) tuples), or None.

	if listitems is not None:
	self._batch_appends(listitems)

	if dictitems is not None:
	self._batch_setitems(dictitems)

	if state is not None:
	if state_setter is None:
	save(state)
	write(BUILD)
	else:
	# If a state_setter is specified, call it instead of load_build
	# to update obj's with its previous state.
	# First, push state_setter and its tuple of expected arguments
	# (obj, state) onto the stack.
	save(state_setter)
	save(obj) # simple BINGET opcode as obj is already memoized.
	save(state)
	write(TUPLE2)
	# Trigger a state_setter(obj, state) function call.
	write(REDUCE)
	# The purpose of state_setter is to carry-out an
	# inplace modification of obj. We do not care about what the
	# method might return, so its output is eventually removed from
	# the stack.
	write(POP)

	# Methods below this point are dispatched through the dispatch table

	dispatch = {}

	def save_none(self, obj):
	self.write(NONE)
	dispatch[type(None)] = save_none

	def save_bool(self, obj):
	if self.proto >= 2:
	self.write(NEWTRUE if obj else NEWFALSE)
	else:
	self.write(TRUE if obj else FALSE)
	dispatch[bool] = save_bool

	def save_long(self, obj):
	if self.bin:
	# If the int is small enough to fit in a signed 4-byte 2's-comp
	# format, we can store it more efficiently than the general
	# case.
	# First one- and two-byte unsigned ints:
	if obj >= 0:
	if obj <= 0xff:
	self.write(BININT1 + pack("<B", obj))
	return
	if obj <= 0xffff:
	self.write(BININT2 + pack("<H", obj))
	return
	# Next check for 4-byte signed ints:
	if -0x80000000 <= obj <= 0x7fffffff:
	self.write(BININT + pack("<i", obj))
	return
	if self.proto >= 2:
	encoded = encode_long(obj)
	n = len(encoded)
	if n < 256:
	self.write(LONG1 + pack("<B", n) + encoded)
	else:
	self.write(LONG4 + pack("<i", n) + encoded)
	return
	if -0x80000000 <= obj <= 0x7fffffff:
	self.write(INT + repr(obj).encode("ascii") + b'\n')
	else:
	self.write(LONG + repr(obj).encode("ascii") + b'L\n')
	dispatch[int] = save_long

	def save_float(self, obj):
	if self.bin:
	self.write(BINFLOAT + pack('>d', obj))
	else:
	self.write(FLOAT + repr(obj).encode("ascii") + b'\n')
	dispatch[float] = save_float

	def save_bytes(self, obj):
	if self.proto < 3:
	if not obj: # bytes object is empty
	self.save_reduce(bytes, (), obj=obj)
	else:
	self.save_reduce(codecs.encode,
	(str(obj, 'latin1'), 'latin1'), obj=obj)
	return
	n = len(obj)
	if n <= 0xff:
	self.write(SHORT_BINBYTES + pack("<B", n) + obj)
	elif n > 0xffffffff and self.proto >= 4:
	self._write_large_bytes(BINBYTES8 + pack("<Q", n), obj)
	elif n >= self.framer._FRAME_SIZE_TARGET:
	self._write_large_bytes(BINBYTES + pack("<I", n), obj)
	else:
	self.write(BINBYTES + pack("<I", n) + obj)
	self.memoize(obj)
	dispatch[bytes] = save_bytes

	def save_bytearray(self, obj):
	if self.proto < 5:
	if not obj: # bytearray is empty
	self.save_reduce(bytearray, (), obj=obj)
	else:
	self.save_reduce(bytearray, (bytes(obj),), obj=obj)
	return
	n = len(obj)
	if n >= self.framer._FRAME_SIZE_TARGET:
	self._write_large_bytes(BYTEARRAY8 + pack("<Q", n), obj)
	else:
	self.write(BYTEARRAY8 + pack("<Q", n) + obj)
	dispatch[bytearray] = save_bytearray

	if _HAVE_PICKLE_BUFFER:
	def save_picklebuffer(self, obj):
	if self.proto < 5:
	raise PicklingError("PickleBuffer can only pickled with "
	"protocol >= 5")
	with obj.raw() as m:
	if not m.contiguous:
	raise PicklingError("PickleBuffer can not be pickled when "
	"pointing to a non-contiguous buffer")
	in_band = True
	if self._buffer_callback is not None:
	in_band = bool(self._buffer_callback(obj))
	if in_band:
	# Write data in-band
	# XXX The C implementation avoids a copy here
	if m.readonly:
	self.save_bytes(m.tobytes())
	else:
	self.save_bytearray(m.tobytes())
	else:
	# Write data out-of-band
	self.write(NEXT_BUFFER)
	if m.readonly:
	self.write(READONLY_BUFFER)

	dispatch[PickleBuffer] = save_picklebuffer

	def save_str(self, obj):
	if self.bin:
	encoded = obj.encode('utf-8', 'surrogatepass')
	n = len(encoded)
	if n <= 0xff and self.proto >= 4:
	self.write(SHORT_BINUNICODE + pack("<B", n) + encoded)
	elif n > 0xffffffff and self.proto >= 4:
	self._write_large_bytes(BINUNICODE8 + pack("<Q", n), encoded)
	elif n >= self.framer._FRAME_SIZE_TARGET:
	self._write_large_bytes(BINUNICODE + pack("<I", n), encoded)
	else:
	self.write(BINUNICODE + pack("<I", n) + encoded)
	else:
	obj = obj.replace("\\", "\\u005c")
	obj = obj.replace("\0", "\\u0000")
	obj = obj.replace("\n", "\\u000a")
	obj = obj.replace("\r", "\\u000d")
	obj = obj.replace("\x1a", "\\u001a") # EOF on DOS
	self.write(UNICODE + obj.encode('raw-unicode-escape') +
	b'\n')
	self.memoize(obj)
	dispatch[str] = save_str

	def save_tuple(self, obj):
	if not obj: # tuple is empty
	if self.bin:
	self.write(EMPTY_TUPLE)
	else:
	self.write(MARK + TUPLE)
	return

	n = len(obj)
	save = self.save
	memo = self.memo
	if n <= 3 and self.proto >= 2:
	for element in obj:
	save(element)
	# Subtle. Same as in the big comment below.
	if id(obj) in memo:
	get = self.get(memo[id(obj)][0])
	self.write(POP * n + get)
	else:
	self.write(_tuplesize2code[n])
	self.memoize(obj)
	return

	# proto 0 or proto 1 and tuple isn't empty, or proto > 1 and tuple
	# has more than 3 elements.
	write = self.write
	write(MARK)
	for element in obj:
	save(element)

	if id(obj) in memo:
	# Subtle. d was not in memo when we entered save_tuple(), so
	# the process of saving the tuple's elements must have saved
	# the tuple itself: the tuple is recursive. The proper action
	# now is to throw away everything we put on the stack, and
	# simply GET the tuple (it's already constructed). This check
	# could have been done in the "for element" loop instead, but
	# recursive tuples are a rare thing.
	get = self.get(memo[id(obj)][0])
	if self.bin:
	write(POP_MARK + get)
	else: # proto 0 -- POP_MARK not available
	write(POP * (n+1) + get)
	return

	# No recursion.
	write(TUPLE)
	self.memoize(obj)

	dispatch[tuple] = save_tuple

	def save_list(self, obj):
	if self.bin:
	self.write(EMPTY_LIST)
	else: # proto 0 -- can't use EMPTY_LIST
	self.write(MARK + LIST)

	self.memoize(obj)
	self._batch_appends(obj)

	dispatch[list] = save_list

	_BATCHSIZE = 1000

	def _batch_appends(self, items):
	# Helper to batch up APPENDS sequences
	save = self.save
	write = self.write

	if not self.bin:
	for x in items:
	save(x)
	write(APPEND)
	return

	it = iter(items)
	while True:
	tmp = list(islice(it, self._BATCHSIZE))
	n = len(tmp)
	if n > 1:
	write(MARK)
	for x in tmp:
	save(x)
	write(APPENDS)
	elif n:
	save(tmp[0])
	write(APPEND)
	# else tmp is empty, and we're done
	if n < self._BATCHSIZE:
	return

	def save_dict(self, obj):
	if self.bin:
	self.write(EMPTY_DICT)
	else: # proto 0 -- can't use EMPTY_DICT
	self.write(MARK + DICT)

	self.memoize(obj)
	self._batch_setitems(obj.items())

	dispatch[dict] = save_dict
	if PyStringMap is not None:
	dispatch[PyStringMap] = save_dict

	def _batch_setitems(self, items):
	# Helper to batch up SETITEMS sequences; proto >= 1 only
	save = self.save
	write = self.write

	if not self.bin:
	for k, v in items:
	save(k)
	save(v)
	write(SETITEM)
	return

	it = iter(items)
	while True:
	tmp = list(islice(it, self._BATCHSIZE))
	n = len(tmp)
	if n > 1:
	write(MARK)
	for k, v in tmp:
	save(k)
	save(v)
	write(SETITEMS)
	elif n:
	k, v = tmp[0]
	save(k)
	save(v)
	write(SETITEM)
	# else tmp is empty, and we're done
	if n < self._BATCHSIZE:
	return

	def save_set(self, obj):
	save = self.save
	write = self.write

	if self.proto < 4:
	self.save_reduce(set, (list(obj),), obj=obj)
	return

	write(EMPTY_SET)
	self.memoize(obj)

	it = iter(obj)
	while True:
	batch = list(islice(it, self._BATCHSIZE))
	n = len(batch)
	if n > 0:
	write(MARK)
	for item in batch:
	save(item)
	write(ADDITEMS)
	if n < self._BATCHSIZE:
	return
	dispatch[set] = save_set

	def save_frozenset(self, obj):
	save = self.save
	write = self.write

	if self.proto < 4:
	self.save_reduce(frozenset, (list(obj),), obj=obj)
	return

	write(MARK)
	for item in obj:
	save(item)

	if id(obj) in self.memo:
	# If the object is already in the memo, this means it is
	# recursive. In this case, throw away everything we put on the
	# stack, and fetch the object back from the memo.
	write(POP_MARK + self.get(self.memo[id(obj)][0]))
	return

	write(FROZENSET)
	self.memoize(obj)
	dispatch[frozenset] = save_frozenset

	def save_global(self, obj, name=None):
	write = self.write
	memo = self.memo

	if name is None:
	name = getattr(obj, '__qualname__', None)
	if name is None:
	name = obj.__name__

	module_name = whichmodule(obj, name)
	try:
	__import__(module_name, level=0)
	module = sys.modules[module_name]
	obj2, parent = _getattribute(module, name)
	except (ImportError, KeyError, AttributeError):
	raise PicklingError(
	"Can't pickle %r: it's not found as %s.%s" %
	(obj, module_name, name)) from None
	else:
	if obj2 is not obj:
	raise PicklingError(
	"Can't pickle %r: it's not the same object as %s.%s" %
	(obj, module_name, name))

	if self.proto >= 2:
	code = _extension_registry.get((module_name, name))
	if code:
	assert code > 0
	if code <= 0xff:
	write(EXT1 + pack("<B", code))
	elif code <= 0xffff:
	write(EXT2 + pack("<H", code))
	else:
	write(EXT4 + pack("<i", code))
	return
	lastname = name.rpartition('.')[2]
	if parent is module:
	name = lastname
	# Non-ASCII identifiers are supported only with protocols >= 3.
	if self.proto >= 4:
	self.save(module_name)
	self.save(name)
	write(STACK_GLOBAL)
	elif parent is not module:
	self.save_reduce(getattr, (parent, lastname))
	elif self.proto >= 3:
	write(GLOBAL + bytes(module_name, "utf-8") + b'\n' +
	bytes(name, "utf-8") + b'\n')
	else:
	if self.fix_imports:
	r_name_mapping = _compat_pickle.REVERSE_NAME_MAPPING
	r_import_mapping = _compat_pickle.REVERSE_IMPORT_MAPPING
	if (module_name, name) in r_name_mapping:
	module_name, name = r_name_mapping[(module_name, name)]
	elif module_name in r_import_mapping:
	module_name = r_import_mapping[module_name]
	try:
	write(GLOBAL + bytes(module_name, "ascii") + b'\n' +
	bytes(name, "ascii") + b'\n')
	except UnicodeEncodeError:
	raise PicklingError(
	"can't pickle global identifier '%s.%s' using "
	"pickle protocol %i" % (module, name, self.proto)) from None

	self.memoize(obj)

	def save_type(self, obj):
	if obj is type(None):
	return self.save_reduce(type, (None,), obj=obj)
	elif obj is type(NotImplemented):
	return self.save_reduce(type, (NotImplemented,), obj=obj)
	elif obj is type(...):
	return self.save_reduce(type, (...,), obj=obj)
	return self.save_global(obj)

	dispatch[FunctionType] = save_global
	dispatch[type] = save_type


	# Unpickling machinery

	class _Unpickler:

	def __init__(self, file, *, fix_imports=True,
	encoding="ASCII", errors="strict", buffers=None):
	"""This takes a binary file for reading a pickle data stream.

	The protocol version of the pickle is detected automatically, so
	no proto argument is needed.

	The argument file must have two methods, a read() method that
	takes an integer argument, and a readline() method that requires
	no arguments. Both methods should return bytes. Thus file
	can be a binary file object opened for reading, an io.BytesIO
	object, or any other custom object that meets this interface.

	The file-like object must have two methods, a read() method
	that takes an integer argument, and a readline() method that
	requires no arguments. Both methods should return bytes.
	Thus file-like object can be a binary file object opened for
	reading, a BytesIO object, or any other custom object that
	meets this interface.

	If buffers is not None, it should be an iterable of buffer-enabled
	objects that is consumed each time the pickle stream references
	an out-of-band buffer view. Such buffers have been given in order
	to the buffer_callback of a Pickler object.

	If buffers is None (the default), then the buffers are taken
	from the pickle stream, assuming they are serialized there.
	It is an error for buffers to be None if the pickle stream
	was produced with a non-None buffer_callback.

	Other optional arguments are fix_imports, encoding and
	errors, which are used to control compatibility support for
	pickle stream generated by Python 2. If fix_imports is True,
	pickle will try to map the old Python 2 names to the new names
	used in Python 3. The encoding and errors tell pickle how
	to decode 8-bit string instances pickled by Python 2; these
	default to 'ASCII' and 'strict', respectively. encoding can be
	'bytes' to read these 8-bit string instances as bytes objects.
	"""
	self._buffers = iter(buffers) if buffers is not None else None
	self._file_readline = file.readline
	self._file_read = file.read
	self.memo = {}
	self.encoding = encoding
	self.errors = errors
	self.proto = 0
	self.fix_imports = fix_imports

	def load(self):
	"""Read a pickled object representation from the open file.

	Return the reconstituted object hierarchy specified in the file.
	"""
	# Check whether Unpickler was initialized correctly. This is
	# only needed to mimic the behavior of _pickle.Unpickler.dump().
	if not hasattr(self, "_file_read"):
	raise UnpicklingError("Unpickler.__init__() was not called by "
	"%s.__init__()" % (self.__class__.__name__,))
	self._unframer = _Unframer(self._file_read, self._file_readline)
	self.read = self._unframer.read
	self.readinto = self._unframer.readinto
	self.readline = self._unframer.readline
	self.metastack = []
	self.stack = []
	self.append = self.stack.append
	self.proto = 0
	read = self.read
	dispatch = self.dispatch
	try:
	while True:
	key = read(1)
	if not key:
	raise EOFError
	assert isinstance(key, bytes_types)
	dispatch[key[0]](self)
	except _Stop as stopinst:
	return stopinst.value

	# Return a list of items pushed in the stack after last MARK instruction.
	def pop_mark(self):
	items = self.stack
	self.stack = self.metastack.pop()
	self.append = self.stack.append
	return items

	def persistent_load(self, pid):
	raise UnpicklingError("unsupported persistent id encountered")

	dispatch = {}

	def load_proto(self):
	proto = self.read(1)[0]
	if not 0 <= proto <= HIGHEST_PROTOCOL:
	raise ValueError("unsupported pickle protocol: %d" % proto)
	self.proto = proto
	dispatch[PROTO[0]] = load_proto

	def load_frame(self):
	frame_size, = unpack('<Q', self.read(8))
	if frame_size > sys.maxsize:
	raise ValueError("frame size > sys.maxsize: %d" % frame_size)
	self._unframer.load_frame(frame_size)
	dispatch[FRAME[0]] = load_frame

	def load_persid(self):
	try:
	pid = self.readline()[:-1].decode("ascii")
	except UnicodeDecodeError:
	raise UnpicklingError(
	"persistent IDs in protocol 0 must be ASCII strings")
	self.append(self.persistent_load(pid))
	dispatch[PERSID[0]] = load_persid

	def load_binpersid(self):
	pid = self.stack.pop()
	self.append(self.persistent_load(pid))
	dispatch[BINPERSID[0]] = load_binpersid

	def load_none(self):
	self.append(None)
	dispatch[NONE[0]] = load_none

	def load_false(self):
	self.append(False)
	dispatch[NEWFALSE[0]] = load_false

	def load_true(self):
	self.append(True)
	dispatch[NEWTRUE[0]] = load_true

	def load_int(self):
	data = self.readline()
	if data == FALSE[1:]:
	val = False
	elif data == TRUE[1:]:
	val = True
	else:
	val = int(data, 0)
	self.append(val)
	dispatch[INT[0]] = load_int

	def load_binint(self):
	self.append(unpack('<i', self.read(4))[0])
	dispatch[BININT[0]] = load_binint

	def load_binint1(self):
	self.append(self.read(1)[0])
	dispatch[BININT1[0]] = load_binint1

	def load_binint2(self):
	self.append(unpack('<H', self.read(2))[0])
	dispatch[BININT2[0]] = load_binint2

	def load_long(self):
	val = self.readline()[:-1]
	if val and val[-1] == b'L'[0]:
	val = val[:-1]
	self.append(int(val, 0))
	dispatch[LONG[0]] = load_long

	def load_long1(self):
	n = self.read(1)[0]
	data = self.read(n)
	self.append(decode_long(data))
	dispatch[LONG1[0]] = load_long1

	def load_long4(self):
	n, = unpack('<i', self.read(4))
	if n < 0:
	# Corrupt or hostile pickle -- we never write one like this
	raise UnpicklingError("LONG pickle has negative byte count")
	data = self.read(n)
	self.append(decode_long(data))
	dispatch[LONG4[0]] = load_long4

	def load_float(self):
	self.append(float(self.readline()[:-1]))
	dispatch[FLOAT[0]] = load_float

	def load_binfloat(self):
	self.append(unpack('>d', self.read(8))[0])
	dispatch[BINFLOAT[0]] = load_binfloat

	def _decode_string(self, value):
	# Used to allow strings from Python 2 to be decoded either as
	# bytes or Unicode strings. This should be used only with the
	# STRING, BINSTRING and SHORT_BINSTRING opcodes.
	if self.encoding == "bytes":
	return value
	else:
	return value.decode(self.encoding, self.errors)

	def load_string(self):
	data = self.readline()[:-1]
	# Strip outermost quotes
	if len(data) >= 2 and data[0] == data[-1] and data[0] in b'"\'':
	data = data[1:-1]
	else:
	raise UnpicklingError("the STRING opcode argument must be quoted")
	self.append(self._decode_string(codecs.escape_decode(data)[0]))
	dispatch[STRING[0]] = load_string

	def load_binstring(self):
	# Deprecated BINSTRING uses signed 32-bit length
	len, = unpack('<i', self.read(4))
	if len < 0:
	raise UnpicklingError("BINSTRING pickle has negative byte count")
	data = self.read(len)
	self.append(self._decode_string(data))
	dispatch[BINSTRING[0]] = load_binstring

	def load_binbytes(self):
	len, = unpack('<I', self.read(4))
	if len > maxsize:
	raise UnpicklingError("BINBYTES exceeds system's maximum size "
	"of %d bytes" % maxsize)
	self.append(self.read(len))
	dispatch[BINBYTES[0]] = load_binbytes

	def load_unicode(self):
	self.append(str(self.readline()[:-1], 'raw-unicode-escape'))
	dispatch[UNICODE[0]] = load_unicode

	def load_binunicode(self):
	len, = unpack('<I', self.read(4))
	if len > maxsize:
	raise UnpicklingError("BINUNICODE exceeds system's maximum size "
	"of %d bytes" % maxsize)
	self.append(str(self.read(len), 'utf-8', 'surrogatepass'))
	dispatch[BINUNICODE[0]] = load_binunicode

	def load_binunicode8(self):
	len, = unpack('<Q', self.read(8))
	if len > maxsize:
	raise UnpicklingError("BINUNICODE8 exceeds system's maximum size "
	"of %d bytes" % maxsize)
	self.append(str(self.read(len), 'utf-8', 'surrogatepass'))
	dispatch[BINUNICODE8[0]] = load_binunicode8

	def load_binbytes8(self):
	len, = unpack('<Q', self.read(8))
	if len > maxsize:
	raise UnpicklingError("BINBYTES8 exceeds system's maximum size "
	"of %d bytes" % maxsize)
	self.append(self.read(len))
	dispatch[BINBYTES8[0]] = load_binbytes8

	def load_bytearray8(self):
	len, = unpack('<Q', self.read(8))
	if len > maxsize:
	raise UnpicklingError("BYTEARRAY8 exceeds system's maximum size "
	"of %d bytes" % maxsize)
	b = bytearray(len)
	self.readinto(b)
	self.append(b)
	dispatch[BYTEARRAY8[0]] = load_bytearray8

	def load_next_buffer(self):
	if self._buffers is None:
	raise UnpicklingError("pickle stream refers to out-of-band data "
	"but no buffers argument was given")
	try:
	buf = next(self._buffers)
	except StopIteration:
	raise UnpicklingError("not enough out-of-band buffers")
	self.append(buf)
	dispatch[NEXT_BUFFER[0]] = load_next_buffer

	def load_readonly_buffer(self):
	buf = self.stack[-1]
	with memoryview(buf) as m:
	if not m.readonly:
	self.stack[-1] = m.toreadonly()
	dispatch[READONLY_BUFFER[0]] = load_readonly_buffer

	def load_short_binstring(self):
	len = self.read(1)[0]
	data = self.read(len)
	self.append(self._decode_string(data))
	dispatch[SHORT_BINSTRING[0]] = load_short_binstring

	def load_short_binbytes(self):
	len = self.read(1)[0]
	self.append(self.read(len))
	dispatch[SHORT_BINBYTES[0]] = load_short_binbytes

	def load_short_binunicode(self):
	len = self.read(1)[0]
	self.append(str(self.read(len), 'utf-8', 'surrogatepass'))
	dispatch[SHORT_BINUNICODE[0]] = load_short_binunicode

	def load_tuple(self):
	items = self.pop_mark()
	self.append(tuple(items))
	dispatch[TUPLE[0]] = load_tuple

	def load_empty_tuple(self):
	self.append(())
	dispatch[EMPTY_TUPLE[0]] = load_empty_tuple

	def load_tuple1(self):
	self.stack[-1] = (self.stack[-1],)
	dispatch[TUPLE1[0]] = load_tuple1

	def load_tuple2(self):
	self.stack[-2:] = [(self.stack[-2], self.stack[-1])]
	dispatch[TUPLE2[0]] = load_tuple2

	def load_tuple3(self):
	self.stack[-3:] = [(self.stack[-3], self.stack[-2], self.stack[-1])]
	dispatch[TUPLE3[0]] = load_tuple3

	def load_empty_list(self):
	self.append([])
	dispatch[EMPTY_LIST[0]] = load_empty_list

	def load_empty_dictionary(self):
	self.append({})
	dispatch[EMPTY_DICT[0]] = load_empty_dictionary

	def load_empty_set(self):
	self.append(set())
	dispatch[EMPTY_SET[0]] = load_empty_set

	def load_frozenset(self):
	items = self.pop_mark()
	self.append(frozenset(items))
	dispatch[FROZENSET[0]] = load_frozenset

	def load_list(self):
	items = self.pop_mark()
	self.append(items)
	dispatch[LIST[0]] = load_list

	def load_dict(self):
	items = self.pop_mark()
	d = {items[i]: items[i+1]
	for i in range(0, len(items), 2)}
	self.append(d)
	dispatch[DICT[0]] = load_dict

	# INST and OBJ differ only in how they get a class object. It's not
	# only sensible to do the rest in a common routine, the two routines
	# previously diverged and grew different bugs.
	# klass is the class to instantiate, and k points to the topmost mark
	# object, following which are the arguments for klass.__init__.
	def _instantiate(self, klass, args):
	if (args or not isinstance(klass, type) or
	hasattr(klass, "__getinitargs__")):
	try:
	value = klass(*args)
	except TypeError as err:
	raise TypeError("in constructor for %s: %s" %
	(klass.__name__, str(err)), sys.exc_info()[2])
	else:
	value = klass.__new__(klass)
	self.append(value)

	def load_inst(self):
	module = self.readline()[:-1].decode("ascii")
	name = self.readline()[:-1].decode("ascii")
	klass = self.find_class(module, name)
	self._instantiate(klass, self.pop_mark())
	dispatch[INST[0]] = load_inst

	def load_obj(self):
	# Stack is ... markobject classobject arg1 arg2 ...
	args = self.pop_mark()
	cls = args.pop(0)
	self._instantiate(cls, args)
	dispatch[OBJ[0]] = load_obj

	def load_newobj(self):
	args = self.stack.pop()
	cls = self.stack.pop()
	obj = cls.__new__(cls, *args)
	self.append(obj)
	dispatch[NEWOBJ[0]] = load_newobj

	def load_newobj_ex(self):
	kwargs = self.stack.pop()
	args = self.stack.pop()
	cls = self.stack.pop()
	obj = cls.__new__(cls, args, *kwargs)
	self.append(obj)
	dispatch[NEWOBJ_EX[0]] = load_newobj_ex

	def load_global(self):
	module = self.readline()[:-1].decode("utf-8")
	name = self.readline()[:-1].decode("utf-8")
	klass = self.find_class(module, name)
	self.append(klass)
	dispatch[GLOBAL[0]] = load_global

	def load_stack_global(self):
	name = self.stack.pop()
	module = self.stack.pop()
	if type(name) is not str or type(module) is not str:
	raise UnpicklingError("STACK_GLOBAL requires str")
	self.append(self.find_class(module, name))
	dispatch[STACK_GLOBAL[0]] = load_stack_global

	def load_ext1(self):
	code = self.read(1)[0]
	self.get_extension(code)
	dispatch[EXT1[0]] = load_ext1

	def load_ext2(self):
	code, = unpack('<H', self.read(2))
	self.get_extension(code)
	dispatch[EXT2[0]] = load_ext2

	def load_ext4(self):
	code, = unpack('<i', self.read(4))
	self.get_extension(code)
	dispatch[EXT4[0]] = load_ext4

	def get_extension(self, code):
	nil = []
	obj = _extension_cache.get(code, nil)
	if obj is not nil:
	self.append(obj)
	return
	key = _inverted_registry.get(code)
	if not key:
	if code <= 0: # note that 0 is forbidden
	# Corrupt or hostile pickle.
	raise UnpicklingError("EXT specifies code <= 0")
	raise ValueError("unregistered extension code %d" % code)
	obj = self.find_class(*key)
	_extension_cache[code] = obj
	self.append(obj)

	def find_class(self, module, name):
	# Subclasses may override this.
	sys.audit('pickle.find_class', module, name)
	if self.proto < 3 and self.fix_imports:
	if (module, name) in _compat_pickle.NAME_MAPPING:
	module, name = _compat_pickle.NAME_MAPPING[(module, name)]
	elif module in _compat_pickle.IMPORT_MAPPING:
	module = _compat_pickle.IMPORT_MAPPING[module]
	__import__(module, level=0)
	if self.proto >= 4:
	return _getattribute(sys.modules[module], name)[0]
	else:
	return getattr(sys.modules[module], name)

	def load_reduce(self):
	stack = self.stack
	args = stack.pop()
	func = stack[-1]
	stack[-1] = func(*args)
	dispatch[REDUCE[0]] = load_reduce

	def load_pop(self):
	if self.stack:
	del self.stack[-1]
	else:
	self.pop_mark()
	dispatch[POP[0]] = load_pop

	def load_pop_mark(self):
	self.pop_mark()
	dispatch[POP_MARK[0]] = load_pop_mark

	def load_dup(self):
	self.append(self.stack[-1])
	dispatch[DUP[0]] = load_dup

	def load_get(self):
	i = int(self.readline()[:-1])
	try:
	self.append(self.memo[i])
	except KeyError:
	msg = f'Memo value not found at index {i}'
	raise UnpicklingError(msg) from None
	dispatch[GET[0]] = load_get

	def load_binget(self):
	i = self.read(1)[0]
	try:
	self.append(self.memo[i])
	except KeyError as exc:
	msg = f'Memo value not found at index {i}'
	raise UnpicklingError(msg) from None
	dispatch[BINGET[0]] = load_binget

	def load_long_binget(self):
	i, = unpack('<I', self.read(4))
	try:
	self.append(self.memo[i])
	except KeyError as exc:
	msg = f'Memo value not found at index {i}'
	raise UnpicklingError(msg) from None
	dispatch[LONG_BINGET[0]] = load_long_binget

	def load_put(self):
	i = int(self.readline()[:-1])
	if i < 0:
	raise ValueError("negative PUT argument")
	self.memo[i] = self.stack[-1]
	dispatch[PUT[0]] = load_put

	def load_binput(self):
	i = self.read(1)[0]
	if i < 0:
	raise ValueError("negative BINPUT argument")
	self.memo[i] = self.stack[-1]
	dispatch[BINPUT[0]] = load_binput

	def load_long_binput(self):
	i, = unpack('<I', self.read(4))
	if i > maxsize:
	raise ValueError("negative LONG_BINPUT argument")
	self.memo[i] = self.stack[-1]
	dispatch[LONG_BINPUT[0]] = load_long_binput

	def load_memoize(self):
	memo = self.memo
	memo[len(memo)] = self.stack[-1]
	dispatch[MEMOIZE[0]] = load_memoize

	def load_append(self):
	stack = self.stack
	value = stack.pop()
	list = stack[-1]
	list.append(value)
	dispatch[APPEND[0]] = load_append

	def load_appends(self):
	items = self.pop_mark()
	list_obj = self.stack[-1]
	try:
	extend = list_obj.extend
	except AttributeError:
	pass
	else:
	extend(items)
	return
	# Even if the PEP 307 requires extend() and append() methods,
	# fall back on append() if the object has no extend() method
	# for backward compatibility.
	append = list_obj.append
	for item in items:
	append(item)
	dispatch[APPENDS[0]] = load_appends

	def load_setitem(self):
	stack = self.stack
	value = stack.pop()
	key = stack.pop()
	dict = stack[-1]
	dict[key] = value
	dispatch[SETITEM[0]] = load_setitem

	def load_setitems(self):
	items = self.pop_mark()
	dict = self.stack[-1]
	for i in range(0, len(items), 2):
	dict[items[i]] = items[i + 1]
	dispatch[SETITEMS[0]] = load_setitems

	def load_additems(self):
	items = self.pop_mark()
	set_obj = self.stack[-1]
	if isinstance(set_obj, set):
	set_obj.update(items)
	else:
	add = set_obj.add
	for item in items:
	add(item)
	dispatch[ADDITEMS[0]] = load_additems

	def load_build(self):
	stack = self.stack
	state = stack.pop()
	inst = stack[-1]
	setstate = getattr(inst, "__setstate__", None)
	if setstate is not None:
	setstate(state)
	return
	slotstate = None
	if isinstance(state, tuple) and len(state) == 2:
	state, slotstate = state
	if state:
	inst_dict = inst.__dict__
	intern = sys.intern
	for k, v in state.items():
	if type(k) is str:
	inst_dict[intern(k)] = v
	else:
	inst_dict[k] = v
	if slotstate:
	for k, v in slotstate.items():
	setattr(inst, k, v)
	dispatch[BUILD[0]] = load_build

	def load_mark(self):
	self.metastack.append(self.stack)
	self.stack = []
	self.append = self.stack.append
	dispatch[MARK[0]] = load_mark

	def load_stop(self):
	value = self.stack.pop()
	raise _Stop(value)
	dispatch[STOP[0]] = load_stop


	# Shorthands

	def _dump(obj, file, protocol=None, *, fix_imports=True, buffer_callback=None):
	_Pickler(file, protocol, fix_imports=fix_imports,
	buffer_callback=buffer_callback).dump(obj)

	def _dumps(obj, protocol=None, *, fix_imports=True, buffer_callback=None):
	f = io.BytesIO()
	_Pickler(f, protocol, fix_imports=fix_imports,
	buffer_callback=buffer_callback).dump(obj)
	res = f.getvalue()
	assert isinstance(res, bytes_types)
	return res

	def _load(file, *, fix_imports=True, encoding="ASCII", errors="strict",
	buffers=None):
	return _Unpickler(file, fix_imports=fix_imports, buffers=buffers,
	encoding=encoding, errors=errors).load()

	def _loads(s, /, *, fix_imports=True, encoding="ASCII", errors="strict",
	buffers=None):
	if isinstance(s, str):
	raise TypeError("Can't load pickle from unicode string")
	file = io.BytesIO(s)
	return _Unpickler(file, fix_imports=fix_imports, buffers=buffers,
	encoding=encoding, errors=errors).load()

	# Use the faster _pickle if possible
	try:
	from _pickle import (
	PickleError,
	PicklingError,
	UnpicklingError,
	Pickler,
	Unpickler,
	dump,
	dumps,
	load,
	loads
	)
	except ImportError:
	Pickler, Unpickler = _Pickler, _Unpickler
	dump, dumps, load, loads = _dump, _dumps, _load, _loads

	# Doctest
	def _test():
	import doctest
	return doctest.testmod()

	if __name__ == "__main__":
	import argparse
	parser = argparse.ArgumentParser(
	description='display contents of the pickle files')
	parser.add_argument(
	'pickle_file', type=argparse.FileType('br'),
	nargs='*', help='the pickle file')
	parser.add_argument(
	'-t', '--test', action='store_true',
	help='run self-test suite')
	parser.add_argument(
	'-v', action='store_true',
	help='run verbosely; only affects self-test run')
	args = parser.parse_args()
	if args.test:
	_test()
	else:
	if not args.pickle_file:
	parser.print_help()
	else:
	import pprint
	for f in args.pickle_file:
	obj = load(f)
	pprint.pprint(obj)

May	DEC	Jul
	29
2021	2022	2025