"""Create portable serialized representations of Python objects.



See module cPickle for a (much) faster implementation.

See module copy_reg 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(string) -> object



Misc variables:



    __version__

    format_version

    compatible_formats



"""



__version__ = "$Revision: 65524 $"       # Code version



from types import *

from copy_reg import dispatch_table

from copy_reg import _extension_registry, _inverted_registry, _extension_cache

import marshal

import sys

import struct

import re



__all__ = ["PickleError", "PicklingError", "UnpicklingError", "Pickler",

           "Unpickler", "dump", "dumps", "load", "loads"]



# These are purely informational; no code uses these.

format_version = "2.0"                  # 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

                      ]                 # Old format versions we can read



# Keep in synch with cPickle.  This is the highest protocol number we

# know how to read.

HIGHEST_PROTOCOL = 2



# Why use struct.pack() for pickling but marshal.loads() for

# unpickling?  struct.pack() is 40% faster than marshal.dumps(), but

# marshal.loads() is twice as fast as struct.unpack()!

mloads = marshal.loads



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



# UnicodeType may or may not be exported (normally imported from types)

try:

    UnicodeType

except NameError:

    UnicodeType = 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            = '('   # push special markobject on stack

STOP            = '.'   # every pickle ends with STOP

POP             = '0'   # discard topmost stack item

POP_MARK        = '1'   # discard stack top through topmost markobject

DUP             = '2'   # duplicate top stack item

FLOAT           = 'F'   # push float object; decimal string argument

INT             = 'I'   # push integer or bool; decimal string argument

BININT          = 'J'   # push four-byte signed int

BININT1         = 'K'   # push 1-byte unsigned int

LONG            = 'L'   # push long; decimal string argument

BININT2         = 'M'   # push 2-byte unsigned int

NONE            = 'N'   # push None

PERSID          = 'P'   # push persistent object; id is taken from string arg

BINPERSID       = 'Q'   #  "       "         "  ;  "  "   "     "  stack

REDUCE          = 'R'   # apply callable to argtuple, both on stack

STRING          = 'S'   # push string; NL-terminated string argument

BINSTRING       = 'T'   # push string; counted binary string argument

SHORT_BINSTRING = 'U'   #  "     "   ;    "      "       "      " < 256 bytes

UNICODE         = 'V'   # push Unicode string; raw-unicode-escaped'd argument

BINUNICODE      = 'X'   #   "     "       "  ; counted UTF-8 string argument

APPEND          = 'a'   # append stack top to list below it

BUILD           = 'b'   # call __setstate__ or __dict__.update()

GLOBAL          = 'c'   # push self.find_class(modname, name); 2 string args

DICT            = 'd'   # build a dict from stack items

EMPTY_DICT      = '}'   # push empty dict

APPENDS         = 'e'   # extend list on stack by topmost stack slice

GET             = 'g'   # push item from memo on stack; index is string arg

BINGET          = 'h'   #   "    "    "    "   "   "  ;   "    " 1-byte arg

INST            = 'i'   # build & push class instance

LONG_BINGET     = 'j'   # push item from memo on stack; index is 4-byte arg

LIST            = 'l'   # build list from topmost stack items

EMPTY_LIST      = ']'   # push empty list

OBJ             = 'o'   # build & push class instance

PUT             = 'p'   # store stack top in memo; index is string arg

BINPUT          = 'q'   #   "     "    "   "   " ;   "    " 1-byte arg

LONG_BINPUT     = 'r'   #   "     "    "   "   " ;   "    " 4-byte arg

SETITEM         = 's'   # add key+value pair to dict

TUPLE           = 't'   # build tuple from topmost stack items

EMPTY_TUPLE     = ')'   # push empty tuple

SETITEMS        = 'u'   # modify dict by adding topmost key+value pairs

BINFLOAT        = 'G'   # push float; arg is 8-byte float encoding



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

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



# Protocol 2



PROTO           = '\x80'  # identify pickle protocol

NEWOBJ          = '\x81'  # build object by applying cls.__new__ to argtuple

EXT1            = '\x82'  # push object from extension registry; 1-byte index

EXT2            = '\x83'  # ditto, but 2-byte index

EXT4            = '\x84'  # ditto, but 4-byte index

TUPLE1          = '\x85'  # build 1-tuple from stack top

TUPLE2          = '\x86'  # build 2-tuple from two topmost stack items

TUPLE3          = '\x87'  # build 3-tuple from three topmost stack items

NEWTRUE         = '\x88'  # push True

NEWFALSE        = '\x89'  # push False

LONG1           = '\x8a'  # push long from < 256 bytes

LONG4           = '\x8b'  # push really big long



_tuplesize2code = [EMPTY_TUPLE, TUPLE1, TUPLE2, TUPLE3]





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

del x





# Pickling machinery



class Pickler:



    def __init__(self, file, protocol=None):

        """This takes a file-like object for writing a pickle data stream.



        The optional protocol argument tells the pickler to use the

        given protocol; supported protocols are 0, 1, 2.  The default

        protocol is 0, to be backwards compatible.  (Protocol 0 is the

        only protocol that can be written to a file opened in text

        mode and read back successfully.  When using a protocol higher

        than 0, make sure the file is opened in binary mode, both when

        pickling and unpickling.)



        Protocol 1 is more efficient than protocol 0; protocol 2 is

        more efficient than protocol 1.



        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 parameter must have a write() method that accepts a single

        string argument.  It can thus be an open file object, a StringIO

        object, or any other custom object that meets this interface.



        """

        if protocol is None:

            protocol = 0

        if protocol < 0:

            protocol = HIGHEST_PROTOCOL

        elif not 0 <= protocol <= HIGHEST_PROTOCOL:

            raise ValueError("pickle protocol must be <= %d" % HIGHEST_PROTOCOL)

        self.write = file.write

        self.memo = {}

        self.proto = int(protocol)

        self.bin = protocol >= 1

        self.fast = 0



    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."""

        if self.proto >= 2:

            self.write(PROTO + chr(self.proto))

        self.save(obj)

        self.write(STOP)



    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

        memo_len = len(self.memo)

        self.write(self.put(memo_len))

        self.memo[id(obj)] = memo_len, obj



    # Return a PUT (BINPUT, LONG_BINPUT) opcode string, with argument i.

    def put(self, i, pack=struct.pack):

        if self.bin:

            if i < 256:

                return BINPUT + chr(i)

            else:

                return LONG_BINPUT + pack("<i", i)



        return PUT + repr(i) + '\n'



    # Return a GET (BINGET, LONG_BINGET) opcode string, with argument i.

    def get(self, i, pack=struct.pack):

        if self.bin:

            if i < 256:

                return BINGET + chr(i)

            else:

                return LONG_BINGET + pack("<i", i)



        return GET + repr(i) + '\n'



    def save(self, obj):

        # Check for persistent id (defined by a subclass)

        pid = self.persistent_id(obj)

        if pid:

            self.save_pers(pid)

            return



        # Check the memo

        x = self.memo.get(id(obj))

        if x:

            self.write(self.get(x[0]))

            return



        # Check the type dispatch table

        t = type(obj)

        f = self.dispatch.get(t)

        if f:

            f(self, obj) # Call unbound method with explicit self

            return



        # Check for a class with a custom metaclass; treat as regular class

        try:

            issc = issubclass(t, TypeType)

        except TypeError: # t is not a class (old Boost; see SF #502085)

            issc = 0

        if issc:

            self.save_global(obj)

            return



        # Check copy_reg.dispatch_table

        reduce = dispatch_table.get(t)

        if reduce:

            rv = reduce(obj)

        else:

            # Check for a __reduce_ex__ method, fall back to __reduce__

            reduce = getattr(obj, "__reduce_ex__", None)

            if reduce:

                rv = reduce(self.proto)

            else:

                reduce = getattr(obj, "__reduce__", None)

                if reduce:

                    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 type(rv) is StringType:

            self.save_global(obj, rv)

            return



        # Assert that reduce() returned a tuple

        if type(rv) is not TupleType:

            raise PicklingError("%s must return string or tuple" % reduce)



        # Assert that it returned an appropriately sized tuple

        l = len(rv)

        if not (2 <= l <= 5):

            raise PicklingError("Tuple returned by %s must have "

                                "two to five 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)

            self.write(BINPERSID)

        else:

            self.write(PERSID + str(pid) + '\n')



    def save_reduce(self, func, args, state=None,

                    listitems=None, dictitems=None, obj=None):

        # This API is called by some subclasses



        # Assert that args is a tuple or None

        if not isinstance(args, TupleType):

            raise PicklingError("args from reduce() should be a tuple")



        # Assert that func is callable

        if not hasattr(func, '__call__'):

            raise PicklingError("func from reduce should be callable")



        save = self.save

        write = self.write



        # Protocol 2 special case: if func's name is __newobj__, use NEWOBJ

        if self.proto >= 2 and getattr(func, "__name__", "") == "__newobj__":

            # A __reduce__ implementation can direct protocol 2 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

            # new-style 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:

            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:

            save(state)

            write(BUILD)



    # Methods below this point are dispatched through the dispatch table



    dispatch = {}



    def save_none(self, obj):

        self.write(NONE)

    dispatch[NoneType] = save_none



    def save_bool(self, obj):

        if self.proto >= 2:

            self.write(obj and NEWTRUE or NEWFALSE)

        else:

            self.write(obj and TRUE or FALSE)

    dispatch[bool] = save_bool



    def save_int(self, obj, pack=struct.pack):

        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 + chr(obj))

                    return

                if obj <= 0xffff:

                    self.write("%c%c%c" % (BININT2, obj&0xff, obj>>8))

                    return

            # Next check for 4-byte signed ints:

            high_bits = obj >> 31  # note that Python shift sign-extends

            if high_bits == 0 or high_bits == -1:

                # All high bits are copies of bit 2**31, so the value

                # fits in a 4-byte signed int.

                self.write(BININT + pack("<i", obj))

                return

        # Text pickle, or int too big to fit in signed 4-byte format.

        self.write(INT + repr(obj) + '\n')

    dispatch[IntType] = save_int



    def save_long(self, obj, pack=struct.pack):

        if self.proto >= 2:

            bytes = encode_long(obj)

            n = len(bytes)

            if n < 256:

                self.write(LONG1 + chr(n) + bytes)

            else:

                self.write(LONG4 + pack("<i", n) + bytes)

            return

        self.write(LONG + repr(obj) + '\n')

    dispatch[LongType] = save_long



    def save_float(self, obj, pack=struct.pack):

        if self.bin:

            self.write(BINFLOAT + pack('>d', obj))

        else:

            self.write(FLOAT + repr(obj) + '\n')

    dispatch[FloatType] = save_float



    def save_string(self, obj, pack=struct.pack):

        if self.bin:

            n = len(obj)

            if n < 256:

                self.write(SHORT_BINSTRING + chr(n) + obj)

            else:

                self.write(BINSTRING + pack("<i", n) + obj)

        else:

            self.write(STRING + repr(obj) + '\n')

        self.memoize(obj)

    dispatch[StringType] = save_string



    def save_unicode(self, obj, pack=struct.pack):

        if self.bin:

            encoding = obj.encode('utf-8')

            n = len(encoding)

            self.write(BINUNICODE + pack("<i", n) + encoding)

        else:

            obj = obj.replace("\\", "\\u005c")

            obj = obj.replace("\n", "\\u000a")

            self.write(UNICODE + obj.encode('raw-unicode-escape') + '\n')

        self.memoize(obj)

    dispatch[UnicodeType] = save_unicode



    if StringType == UnicodeType:

        # This is true for Jython

        def save_string(self, obj, pack=struct.pack):

            unicode = obj.isunicode()



            if self.bin:

                if unicode:

                    obj = obj.encode("utf-8")

                l = len(obj)

                if l < 256 and not unicode:

                    self.write(SHORT_BINSTRING + chr(l) + obj)

                else:

                    s = pack("<i", l)

                    if unicode:

                        self.write(BINUNICODE + s + obj)

                    else:

                        self.write(BINSTRING + s + obj)

            else:

                if unicode:

                    obj = obj.replace("\\", "\\u005c")

                    obj = obj.replace("\n", "\\u000a")

                    obj = obj.encode('raw-unicode-escape')

                    self.write(UNICODE + obj + '\n')

                else:

                    self.write(STRING + repr(obj) + '\n')

            self.memoize(obj)

        dispatch[StringType] = save_string



    def save_tuple(self, obj):

        write = self.write

        proto = self.proto



        n = len(obj)

        if n == 0:

            if proto:

                write(EMPTY_TUPLE)

            else:

                write(MARK + TUPLE)

            return



        save = self.save

        memo = self.memo

        if n <= 3 and 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])

                write(POP * n + get)

            else:

                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(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 proto:

                write(POP_MARK + get)

            else:   # proto 0 -- POP_MARK not available

                write(POP * (n+1) + get)

            return



        # No recursion.

        self.write(TUPLE)

        self.memoize(obj)



    dispatch[TupleType] = save_tuple



    # save_empty_tuple() isn't used by anything in Python 2.3.  However, I

    # found a Pickler subclass in Zope3 that calls it, so it's not harmless

    # to remove it.

    def save_empty_tuple(self, obj):

        self.write(EMPTY_TUPLE)



    def save_list(self, obj):

        write = self.write



        if self.bin:

            write(EMPTY_LIST)

        else:   # proto 0 -- can't use EMPTY_LIST

            write(MARK + LIST)



        self.memoize(obj)

        self._batch_appends(iter(obj))



    dispatch[ListType] = save_list



    # Keep in synch with cPickle's BATCHSIZE.  Nothing will break if it gets

    # out of synch, though.

    _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



        r = xrange(self._BATCHSIZE)

        while items is not None:

            tmp = []

            for i in r:

                try:

                    x = items.next()

                    tmp.append(x)

                except StopIteration:

                    items = None

                    break

            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



    def save_dict(self, obj):

        write = self.write



        if self.bin:

            write(EMPTY_DICT)

        else:   # proto 0 -- can't use EMPTY_DICT

            write(MARK + DICT)



        self.memoize(obj)

        self._batch_setitems(obj.iteritems())



    dispatch[DictionaryType] = save_dict

    if not PyStringMap is 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



        r = xrange(self._BATCHSIZE)

        while items is not None:

            tmp = []

            for i in r:

                try:

                    tmp.append(items.next())

                except StopIteration:

                    items = None

                    break

            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



    def save_inst(self, obj):

        cls = obj.__class__



        memo  = self.memo

        write = self.write

        save  = self.save



        if hasattr(obj, '__getinitargs__'):

            args = obj.__getinitargs__()

            len(args) # XXX Assert it's a sequence

            _keep_alive(args, memo)

        else:

            args = ()



        write(MARK)



        if self.bin:

            save(cls)

            for arg in args:

                save(arg)

            write(OBJ)

        else:

            for arg in args:

                save(arg)

            write(INST + cls.__module__ + '\n' + cls.__name__ + '\n')



        self.memoize(obj)



        try:

            getstate = obj.__getstate__

        except AttributeError:

            stuff = obj.__dict__

        else:

            stuff = getstate()

            _keep_alive(stuff, memo)

        save(stuff)

        write(BUILD)



    dispatch[InstanceType] = save_inst



    def save_global(self, obj, name=None, pack=struct.pack):

        write = self.write

        memo = self.memo



        if name is None:

            name = obj.__name__



        module = getattr(obj, "__module__", None)

        if module is None:

            module = whichmodule(obj, name)



        try:

            __import__(module)

            mod = sys.modules[module]

            klass = getattr(mod, name)

        except (ImportError, KeyError, AttributeError):

            raise PicklingError(

                "Can't pickle %r: it's not found as %s.%s" %

                (obj, module, name))

        else:

            if klass is not obj:

                raise PicklingError(

                    "Can't pickle %r: it's not the same object as %s.%s" %

                    (obj, module, name))



        if self.proto >= 2:

            code = _extension_registry.get((module, name))

            if code:

                assert code > 0

                if code <= 0xff:

                    write(EXT1 + chr(code))

                elif code <= 0xffff:

                    write("%c%c%c" % (EXT2, code&0xff, code>>8))

                else:

                    write(EXT4 + pack("<i", code))

                return



        write(GLOBAL + module + '\n' + name + '\n')

        self.memoize(obj)



    dispatch[ClassType] = save_global

    dispatch[FunctionType] = save_global

    dispatch[BuiltinFunctionType] = save_global

    dispatch[TypeType] = save_global



# Pickling helpers



def _keep_alive(x, memo):

    """Keeps a reference to the object x in the memo.



    Because we remember objects by their id, we have

    to assure that possibly temporary objects are kept

    alive by referencing them.

    We store a reference at the id of the memo, which should

    normally not be used unless someone tries to deepcopy

    the memo itself...

    """

    try:

        memo[id(memo)].append(x)

    except KeyError:

        # aha, this is the first one :-)

        memo[id(memo)]=[x]





# A cache for whichmodule(), mapping a function object to the name of

# the module in which the function was found.



classmap = {} # called classmap for backwards compatibility



def whichmodule(func, funcname):

    """Figure out the module in which a function occurs.



    Search sys.modules for the module.

    Cache in classmap.

    Return a module name.

    If the function cannot be found, return "__main__".

    """

    # Python functions should always get an __module__ from their globals.

    mod = getattr(func, "__module__", None)

    if mod is not None:

        return mod

    if func in classmap:

        return classmap[func]



    for name, module in sys.modules.items():

        if module is None:

            continue # skip dummy package entries

        if name != '__main__' and getattr(module, funcname, None) is func:

            break

    else:

        name = '__main__'

    classmap[func] = name

    return name





# Unpickling machinery



class Unpickler:



    def __init__(self, file):

        """This takes a file-like object for reading a pickle data stream.



        The protocol version of the pickle is detected automatically, so no

        proto argument is needed.



        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 a string.  Thus file-like

        object can be a file object opened for reading, a StringIO object,

        or any other custom object that meets this interface.

        """

        self.readline = file.readline

        self.read = file.read

        self.memo = {}



    def load(self):

        """Read a pickled object representation from the open file.



        Return the reconstituted object hierarchy specified in the file.

        """

        self.mark = object() # any new unique object

        self.stack = []

        self.append = self.stack.append

        read = self.read

        dispatch = self.dispatch

        try:

            while 1:

                key = read(1)

                dispatch[key](self)

        except _Stop, stopinst:

            return stopinst.value



    # Return largest index k such that self.stack[k] is self.mark.

    # If the stack doesn't contain a mark, eventually raises IndexError.

    # This could be sped by maintaining another stack, of indices at which

    # the mark appears.  For that matter, the latter stack would suffice,

    # and we wouldn't need to push mark objects on self.stack at all.

    # Doing so is probably a good thing, though, since if the pickle is

    # corrupt (or hostile) we may get a clue from finding self.mark embedded

    # in unpickled objects.

    def marker(self):

        stack = self.stack

        mark = self.mark

        k = len(stack)-1

        while stack[k] is not mark: k = k-1

        return k



    dispatch = {}



    def load_eof(self):

        raise EOFError

    dispatch[''] = load_eof



    def load_proto(self):

        proto = ord(self.read(1))

        if not 0 <= proto <= 2:

            raise ValueError, "unsupported pickle protocol: %d" % proto

    dispatch[PROTO] = load_proto



    def load_persid(self):

        pid = self.readline()[:-1]

        self.append(self.persistent_load(pid))

    dispatch[PERSID] = load_persid



    def load_binpersid(self):

        pid = self.stack.pop()

        self.append(self.persistent_load(pid))

    dispatch[BINPERSID] = load_binpersid



    def load_none(self):

        self.append(None)

    dispatch[NONE] = load_none



    def load_false(self):

        self.append(False)

    dispatch[NEWFALSE] = load_false



    def load_true(self):

        self.append(True)

    dispatch[NEWTRUE] = load_true



    def load_int(self):

        data = self.readline()

        if data == FALSE[1:]:

            val = False

        elif data == TRUE[1:]:

            val = True

        else:

            try:

                val = int(data)

            except ValueError:

                val = long(data)

        self.append(val)

    dispatch[INT] = load_int



    def load_binint(self):

        self.append(mloads('i' + self.read(4)))

    dispatch[BININT] = load_binint



    def load_binint1(self):

        self.append(ord(self.read(1)))

    dispatch[BININT1] = load_binint1



    def load_binint2(self):

        self.append(mloads('i' + self.read(2) + '\000\000'))

    dispatch[BININT2] = load_binint2



    def load_long(self):

        self.append(long(self.readline()[:-1], 0))

    dispatch[LONG] = load_long



    def load_long1(self):

        n = ord(self.read(1))

        bytes = self.read(n)

        self.append(decode_long(bytes))

    dispatch[LONG1] = load_long1



    def load_long4(self):

        n = mloads('i' + self.read(4))

        bytes = self.read(n)

        self.append(decode_long(bytes))

    dispatch[LONG4] = load_long4



    def load_float(self):

        self.append(float(self.readline()[:-1]))

    dispatch[FLOAT] = load_float



    def load_binfloat(self, unpack=struct.unpack):

        self.append(unpack('>d', self.read(8))[0])

    dispatch[BINFLOAT] = load_binfloat



    def load_string(self):

        rep = self.readline()[:-1]

        for q in "\"'": # double or single quote

            if rep.startswith(q):

                if not rep.endswith(q):

                    raise ValueError, "insecure string pickle"

                rep = rep[len(q):-len(q)]

                break

        else:

            raise ValueError, "insecure string pickle"

        self.append(rep.decode("string-escape"))

    dispatch[STRING] = load_string



    def load_binstring(self):

        len = mloads('i' + self.read(4))

        self.append(self.read(len))

    dispatch[BINSTRING] = load_binstring



    def load_unicode(self):

        self.append(unicode(self.readline()[:-1],'raw-unicode-escape'))

    dispatch[UNICODE] = load_unicode



    def load_binunicode(self):

        len = mloads('i' + self.read(4))

        self.append(unicode(self.read(len),'utf-8'))

    dispatch[BINUNICODE] = load_binunicode



    def load_short_binstring(self):

        len = ord(self.read(1))

        self.append(self.read(len))

    dispatch[SHORT_BINSTRING] = load_short_binstring



    def load_tuple(self):

        k = self.marker()

        self.stack[k:] = [tuple(self.stack[k+1:])]

    dispatch[TUPLE] = load_tuple



    def load_empty_tuple(self):

        self.stack.append(())

    dispatch[EMPTY_TUPLE] = load_empty_tuple



    def load_tuple1(self):

        self.stack[-1] = (self.stack[-1],)

    dispatch[TUPLE1] = load_tuple1



    def load_tuple2(self):

        self.stack[-2:] = [(self.stack[-2], self.stack[-1])]

    dispatch[TUPLE2] = load_tuple2



    def load_tuple3(self):

        self.stack[-3:] = [(self.stack[-3], self.stack[-2], self.stack[-1])]

    dispatch[TUPLE3] = load_tuple3



    def load_empty_list(self):

        self.stack.append([])

    dispatch[EMPTY_LIST] = load_empty_list



    def load_empty_dictionary(self):

        self.stack.append({})

    dispatch[EMPTY_DICT] = load_empty_dictionary



    def load_list(self):

        k = self.marker()

        self.stack[k:] = [self.stack[k+1:]]

    dispatch[LIST] = load_list



    def load_dict(self):

        k = self.marker()

        d = {}

        items = self.stack[k+1:]

        for i in range(0, len(items), 2):

            key = items[i]

            value = items[i+1]

            d[key] = value

        self.stack[k:] = [d]

    dispatch[DICT] = 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, k):

        args = tuple(self.stack[k+1:])

        del self.stack[k:]

        instantiated = 0

        if (not args and

                type(klass) is ClassType and

                not hasattr(klass, "__getinitargs__")):

            try:

                value = _EmptyClass()

                value.__class__ = klass

                instantiated = 1

            except RuntimeError:

                # In restricted execution, assignment to inst.__class__ is

                # prohibited

                pass

        if not instantiated:

            try:

                value = klass(*args)

            except TypeError, err:

                raise TypeError, "in constructor for %s: %s" % (

                    klass.__name__, str(err)), sys.exc_info()[2]

        self.append(value)



    def load_inst(self):

        module = self.readline()[:-1]

        name = self.readline()[:-1]

        klass = self.find_class(module, name)

        self._instantiate(klass, self.marker())

    dispatch[INST] = load_inst



    def load_obj(self):

        # Stack is ... markobject classobject arg1 arg2 ...

        k = self.marker()

        klass = self.stack.pop(k+1)

        self._instantiate(klass, k)

    dispatch[OBJ] = load_obj



    def load_newobj(self):

        args = self.stack.pop()

        cls = self.stack[-1]

        obj = cls.__new__(cls, *args)

        self.stack[-1] = obj

    dispatch[NEWOBJ] = load_newobj



    def load_global(self):

        module = self.readline()[:-1]

        name = self.readline()[:-1]

        klass = self.find_class(module, name)

        self.append(klass)

    dispatch[GLOBAL] = load_global



    def load_ext1(self):

        code = ord(self.read(1))

        self.get_extension(code)

    dispatch[EXT1] = load_ext1



    def load_ext2(self):

        code = mloads('i' + self.read(2) + '\000\000')

        self.get_extension(code)

    dispatch[EXT2] = load_ext2



    def load_ext4(self):

        code = mloads('i' + self.read(4))

        self.get_extension(code)

    dispatch[EXT4] = 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:

            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

        __import__(module)

        mod = sys.modules[module]

        klass = getattr(mod, name)

        return klass



    def load_reduce(self):

        stack = self.stack

        args = stack.pop()

        func = stack[-1]

        value = func(*args)

        stack[-1] = value

    dispatch[REDUCE] = load_reduce



    def load_pop(self):

        del self.stack[-1]

    dispatch[POP] = load_pop



    def load_pop_mark(self):

        k = self.marker()

        del self.stack[k:]

    dispatch[POP_MARK] = load_pop_mark



    def load_dup(self):

        self.append(self.stack[-1])

    dispatch[DUP] = load_dup



    def load_get(self):

        self.append(self.memo[self.readline()[:-1]])

    dispatch[GET] = load_get



    def load_binget(self):

        i = ord(self.read(1))

        self.append(self.memo[repr(i)])

    dispatch[BINGET] = load_binget



    def load_long_binget(self):

        i = mloads('i' + self.read(4))

        self.append(self.memo[repr(i)])

    dispatch[LONG_BINGET] = load_long_binget



    def load_put(self):

        self.memo[self.readline()[:-1]] = self.stack[-1]

    dispatch[PUT] = load_put



    def load_binput(self):

        i = ord(self.read(1))

        self.memo[repr(i)] = self.stack[-1]

    dispatch[BINPUT] = load_binput



    def load_long_binput(self):

        i = mloads('i' + self.read(4))

        self.memo[repr(i)] = self.stack[-1]

    dispatch[LONG_BINPUT] = load_long_binput



    def load_append(self):

        stack = self.stack

        value = stack.pop()

        list = stack[-1]

        list.append(value)

    dispatch[APPEND] = load_append



    def load_appends(self):

        stack = self.stack

        mark = self.marker()

        list = stack[mark - 1]

        list.extend(stack[mark + 1:])

        del stack[mark:]

    dispatch[APPENDS] = load_appends



    def load_setitem(self):

        stack = self.stack

        value = stack.pop()

        key = stack.pop()

        dict = stack[-1]

        dict[key] = value

    dispatch[SETITEM] = load_setitem



    def load_setitems(self):

        stack = self.stack

        mark = self.marker()

        dict = stack[mark - 1]

        for i in range(mark + 1, len(stack), 2):

            dict[stack[i]] = stack[i + 1]



        del stack[mark:]

    dispatch[SETITEMS] = load_setitems



    def load_build(self):

        stack = self.stack

        state = stack.pop()

        inst = stack[-1]

        setstate = getattr(inst, "__setstate__", None)

        if setstate:

            setstate(state)

            return

        slotstate = None

        if isinstance(state, tuple) and len(state) == 2:

            state, slotstate = state

        if state:

            try:

                inst.__dict__.update(state)

            except RuntimeError:

                # XXX In restricted execution, the instance's __dict__

                # is not accessible.  Use the old way of unpickling

                # the instance variables.  This is a semantic

                # difference when unpickling in restricted

                # vs. unrestricted modes.

                # Note, however, that cPickle has never tried to do the

                # .update() business, and always uses

                #     PyObject_SetItem(inst.__dict__, key, value) in a

                # loop over state.items().

                for k, v in state.items():

                    setattr(inst, k, v)

        if slotstate:

            for k, v in slotstate.items():

                setattr(inst, k, v)

    dispatch[BUILD] = load_build



    def load_mark(self):

        self.append(self.mark)

    dispatch[MARK] = load_mark



    def load_stop(self):

        value = self.stack.pop()

        raise _Stop(value)

    dispatch[STOP] = load_stop



# Helper class for load_inst/load_obj



class _EmptyClass:

    pass



# Encode/decode longs in linear time.



import binascii as _binascii



def encode_long(x):

    r"""Encode a long to a two's complement little-endian binary string.

    Note that 0L is a special case, returning an empty string, to save a

    byte in the LONG1 pickling context.



    >>> encode_long(0L)

    ''

    >>> encode_long(255L)

    '\xff\x00'

    >>> encode_long(32767L)

    '\xff\x7f'

    >>> encode_long(-256L)

    '\x00\xff'

    >>> encode_long(-32768L)

    '\x00\x80'

    >>> encode_long(-128L)

    '\x80'

    >>> encode_long(127L)

    '\x7f'

    >>>

    """



    if x == 0:

        return ''

    if x > 0:

        ashex = hex(x)

        assert ashex.startswith("0x")

        njunkchars = 2 + ashex.endswith('L')

        nibbles = len(ashex) - njunkchars

        if nibbles & 1:

            # need an even # of nibbles for unhexlify

            ashex = "0x0" + ashex[2:]

        elif int(ashex[2], 16) >= 8:

            # "looks negative", so need a byte of sign bits

            ashex = "0x00" + ashex[2:]

    else:

        # Build the 256's-complement:  (1L << nbytes) + x.  The trick is

        # to find the number of bytes in linear time (although that should

        # really be a constant-time task).

        ashex = hex(-x)

        assert ashex.startswith("0x")

        njunkchars = 2 + ashex.endswith('L')

        nibbles = len(ashex) - njunkchars

        if nibbles & 1:

            # Extend to a full byte.

            nibbles += 1

        nbits = nibbles * 4

        x += 1L << nbits

        assert x > 0

        ashex = hex(x)

        njunkchars = 2 + ashex.endswith('L')

        newnibbles = len(ashex) - njunkchars

        if newnibbles < nibbles:

            ashex = "0x" + "0" * (nibbles - newnibbles) + ashex[2:]

        if int(ashex[2], 16) < 8:

            # "looks positive", so need a byte of sign bits

            ashex = "0xff" + ashex[2:]



    if ashex.endswith('L'):

        ashex = ashex[2:-1]

    else:

        ashex = ashex[2:]

    assert len(ashex) & 1 == 0, (x, ashex)

    binary = _binascii.unhexlify(ashex)

    return binary[::-1]



def decode_long(data):

    r"""Decode a long from a two's complement little-endian binary string.



    >>> decode_long('')

    0L

    >>> decode_long("\xff\x00")

    255L

    >>> decode_long("\xff\x7f")

    32767L

    >>> decode_long("\x00\xff")

    -256L

    >>> decode_long("\x00\x80")

    -32768L

    >>> decode_long("\x80")

    -128L

    >>> decode_long("\x7f")

    127L

    """



    nbytes = len(data)

    if nbytes == 0:

        return 0L

    ashex = _binascii.hexlify(data[::-1])

    n = long(ashex, 16) # quadratic time before Python 2.3; linear now

    if data[-1] >= '\x80':

        n -= 1L << (nbytes * 8)

    return n



# Shorthands



try:

    from cStringIO import StringIO

except ImportError:

    from StringIO import StringIO



def dump(obj, file, protocol=None):

    Pickler(file, protocol).dump(obj)



def dumps(obj, protocol=None):

    file = StringIO()

    Pickler(file, protocol).dump(obj)

    return file.getvalue()



def load(file):

    return Unpickler(file).load()



def loads(str):

    file = StringIO(str)

    return Unpickler(file).load()



# Doctest



def _test():

    import doctest

    return doctest.testmod()



if __name__ == "__main__":

    _test()

