#!/usr/bin/env python

# Copyright, license and disclaimer are at the end of this file.

# This is the latest, enhanced version of the asizeof.py recipes at
# <http://aspn.activestate.com/ASPN/Cookbook/Python/Recipe/546530>
# <http://aspn.activestate.com/ASPN/Cookbook/Python/Recipe/544288>

'''
This module exposes 9 functions and 2 classes to obtain lengths and
sizes of Python objects (for Python 2.5 or later).

Earlier versions of this module supported Python versions down to
Python 2.2. If you are running Python < 2.5 please consider
downgrading Pympler to version 0.3.x.

**Public Functions** [#unsafe]_

   Function **asizeof** calculates the combined (approximate) size
   of one or several Python objects in bytes.  Function **asizesof**
   returns a tuple containing the (approximate) size in bytes for
   each given Python object separately.  Function **asized** returns
   for each object an instance of class **Asized** containing all the
   size information of the object and a tuple with the referents.

   Functions **basicsize** and **itemsize** return the basic resp. item
   size of the given object.

   Function **flatsize** returns the flat size of a Python object in
   bytes defined as the basic size plus the item size times the
   length of the given object.

   Function **leng** returns the length of an object, like standard
   ``len`` but extended for several types, e.g. the **leng** of a
   multi-precision int (or long) is the number of ``digits`` [#digit]_.
   The length of most mutable sequence objects includes an estimate of
   the over-allocation and therefore, the **leng** value may differ
   from the standard ``len`` result.

   Function **refs** returns (a generator for) the referents of the
   given object, i.e. the objects referenced by the given object.

   Certain classes are known to be sub-classes of or to behave as
   dict objects.  Function **adict** can be used to install other
   class objects to be treated like dict.

**Public Classes** [#unsafe]_

   An instance of class **Asized** is returned for each object sized
   with the **asized** function or method.

   Class **Asizer** may be used to accumulate the results of several
   **asizeof** or **asizesof** calls.  After creating an **Asizer** instance,
   use methods **asizeof** and **asizesof** as needed to size any
   number of additional objects.

   Call methods **exclude_refs** and/or **exclude_types** to exclude
   references to resp. instances or types of certain objects.
   Use one of the **print\_... methods** to report the statistics.

**Duplicate Objects**

   Any duplicate, given objects are sized only once and the size
   is included in the combined total only once.  But functions
   **asizesof** and **asized** do return a size value resp. an
   **Asized** instance for each given object, including duplicates.

**Definitions** [#arb]_

   The size of an object is defined as the sum of the flat size
   of the object plus the sizes of any referents.  Referents are
   visited recursively up to a given limit.  However, the size
   of objects referenced multiple times is included only once.

   The flat size of an object is defined as the basic size of the
   object plus the item size times the number of allocated items.
   The flat size does include the size for the items (references
   to the referents), but not the referents themselves.

   The flat size returned by function **flatsize** equals the result
   of the **asizeof** function with options *code=True*, *ignored=False*,
   *limit=0* and option *align* set to the same value.

   The accurate flat size for an object is obtained from function
   ``sys.getsizeof()`` where available.  Otherwise, the length and
   size of sequence objects as dicts, lists, sets, etc. is based
   on an estimate for the number of allocated items.  As a result,
   the reported length and size may substantially differ from the
   actual length and size.

   The basic and item sizes are obtained from the ``__basicsize__``
   resp. ``__itemsize__`` attributes of the (type of the) object.
   Where necessary (e.g. sequence objects), a zero ``__itemsize__``
   is replaced by the size of a corresponding C type.  The basic
   size (of GC managed objects) objects includes the overhead for
   Python's garbage collector (GC) as well as the space needed for
   ``refcounts`` (used only in certain Python builds).

   Optionally, size values can be aligned to any power of 2 multiple.

**Size of (byte)code**

   The (byte)code size of objects like classes, functions, methods,
   modules, etc. can be included by setting option *code=True*.

   Iterators are handled similar to sequences: iterated object(s)
   are sized like referents, only if the recursion *limit* permits.
   Also, function ``gc.get_referents()`` must return the referent
   object of iterators.

   Generators are sized as (byte)code only, but the generated
   objects are never sized.

**Old- and New-style Classes**

   All old- and new-style class, instance and type objects, are
   handled uniformly such that (a) instance objects are distinguished
   from class objects and (b) instances of different old-style classes
   can be dealt with separately.

   Class and type objects are represented as <class ....* def>
   resp. <type ... def> where an '*' indicates an old-style class
   and the  def suffix marks the definition object.  Instances of
   old-style classes are shown as new-style ones but with an '*'
   at the end of the name, like <class module.name*>.

**Ignored Objects**

   To avoid excessive sizes, several object types are ignored [#arb]_ by
   default, e.g. built-in functions, built-in types and classes [#bi]_,
   function globals and module referents.  However, any instances
   thereof are sized and module objects will be sized when passed
   as given objects.  Ignored object types are included if option
   *ignored* is set accordingly.

   In addition, many ``__...__`` attributes of callable objects are
   ignored [#arb]_, except crucial ones, e.g. class attributes ``__dict__``,
   ``__doc__``, ``__name__`` and ``__slots__``.  For more details, see the
   type-specific ``_..._refs()`` and ``_len_...()`` functions below.

.. rubric:: Footnotes
.. [#unsafe] The functions and classes in this module are not thread-safe.

.. [#digit] See Python source file ``.../Include/longinterp.h`` for the
     C ``typedef`` of ``digit`` used in multi-precision int (or
     long) objects.  The C ``sizeof(digit)`` in bytes can be obtained
     in Python from the int (or long) ``__itemsize__`` attribute.
     Function **leng** determines the number of ``digits`` of an
     int (or long) value.

.. [#arb] These definitions and other assumptions are rather arbitrary
     and may need corrections or adjustments.

.. [#bi] Types and classes are considered built-in if the ``__module__``
     of the type or class is listed in ``_builtin_modules`` below.
'''

from inspect import (isbuiltin, isclass, iscode, isframe, isfunction, ismethod,
                     ismodule, stack)
from math import log
from os import curdir, linesep
from struct import calcsize  # type/class Struct only in Python 2.5+
import sys
import types as Types
import warnings
import weakref as Weakref

__all__ = ['adict', 'asized', 'asizeof', 'asizesof',
           'Asized', 'Asizer',  # classes
           'basicsize', 'flatsize', 'itemsize', 'leng', 'refs']

 # any classes or types in modules listed in _builtin_modules are
 # considered built-in and ignored by default, as built-in functions
if __name__ == '__main__':
    _builtin_modules = (int.__module__, 'types', Exception.__module__)  # , 'weakref'
else:  # treat this very module as built-in
    _builtin_modules = (int.__module__, 'types', Exception.__module__, __name__)  # , 'weakref'

 # sizes of some primitive C types
 # XXX len(pack(T, 0)) == Struct(T).size == calcsize(T)
_sizeof_Cbyte = calcsize('c')  # sizeof(unsigned char)
_sizeof_Clong = calcsize('l')  # sizeof(long)
_sizeof_Cvoidp = calcsize('P')  # sizeof(void*)


def _calcsize(fmt):
    '''struct.calcsize() handling 'z' for Py_ssize_t.
    '''
     # sizeof(long) != sizeof(ssize_t) on LLP64
    if _sizeof_Clong < _sizeof_Cvoidp:  # pragma: no coverage
        z = 'P'
    else:
        z = 'L'
    return calcsize(fmt.replace('z', z))

 # defaults for some basic sizes with 'z' for C Py_ssize_t
_sizeof_CPyCodeObject = _calcsize('Pz10P5i0P')  # sizeof(PyCodeObject)
_sizeof_CPyFrameObject = _calcsize('Pzz13P63i0P')  # sizeof(PyFrameObject)
_sizeof_CPyModuleObject = _calcsize('PzP0P')  # sizeof(PyModuleObject)

 # defaults for some item sizes with 'z' for C Py_ssize_t
_sizeof_CPyDictEntry = _calcsize('z2P')  # sizeof(PyDictEntry)
_sizeof_Csetentry = _calcsize('lP')  # sizeof(setentry)

try:  # C typedef digit for multi-precision int (or long)
    _sizeof_Cdigit = long.__itemsize__
except NameError:  # no long in Python 3.0
    _sizeof_Cdigit = int.__itemsize__
if _sizeof_Cdigit < 2:  # pragma: no coverage
    raise AssertionError('sizeof(%s) bad: %d' % ('digit', _sizeof_Cdigit))

# Get character size for internal unicode representation in Python < 3.3
try:  # sizeof(unicode_char)
    u = unicode('\0')
except NameError:  # no unicode() in Python 3.0
    u = '\0'
u = u.encode('unicode-internal')  # see .../Lib/test/test_sys.py
_sizeof_Cunicode = len(u)
del u

try:  # size of GC header, sizeof(PyGC_Head)
    import _testcapi as t
    _sizeof_CPyGC_Head = t.SIZEOF_PYGC_HEAD  # new in Python 2.6
except (ImportError, AttributeError):  # sizeof(PyGC_Head)
     # alignment should be to sizeof(long double) but there
     # is no way to obtain that value, assume twice double
    t = calcsize('2d') - 1
    _sizeof_CPyGC_Head = (_calcsize('2Pz') + t) & ~t
del t

 # size of refcounts (Python debug build only)
if hasattr(sys, 'gettotalrefcount'):  # pragma: no coverage
    _sizeof_Crefcounts = _calcsize('2z')
else:
    _sizeof_Crefcounts = 0

try:
    from abc import ABCMeta
except ImportError:
    class ABCMeta(type):
        pass

 # some flags from .../Include/object.h
_Py_TPFLAGS_HEAPTYPE = 1 << 9  # Py_TPFLAGS_HEAPTYPE
_Py_TPFLAGS_HAVE_GC = 1 << 14  # Py_TPFLAGS_HAVE_GC

_Type_type = type(type)  # == type and new-style class type


 # compatibility functions for more uniform
 # behavior across Python version 2.2 thu 3.0

def _items(obj):  # dict only
    '''Return iter-/generator, preferably.
    '''
    return getattr(obj, 'iteritems', obj.items)()


def _keys(obj):  # dict only
    '''Return iter-/generator, preferably.
    '''
    return getattr(obj, 'iterkeys', obj.keys)()


def _values(obj):  # dict only
    '''Use iter-/generator, preferably.
    '''
    return getattr(obj, 'itervalues', obj.values)()

try:  # callable() builtin
    _callable = callable
except NameError:  # callable() removed in Python 3.0
    def _callable(obj):
        '''Substitute for callable().'''
        return hasattr(obj, '__call__')

try:  # only used to get the referents of
      # iterators, but gc.get_referents()
      # returns () for dict...-iterators
    from gc import get_referents as _getreferents
except ImportError:
    def _getreferents(unused):
        return ()  # sorry, no refs

 # sys.getsizeof() new in Python 2.6
_getsizeof = getattr(sys, 'getsizeof', None)

version = sys.version_info
_getsizeof_bugs = (getattr(sys, 'getsizeof', None) and
                   (version[0] == 2 and version < (2, 7, 4) or
                    version[0] == 3 and version < (3, 2, 4)))


def _getsizeof_exclude(getsizeof, exclude):
    def _getsizeof_wrapper(obj, default):
        if isinstance(obj, exclude):
            return default
        else:
            return getsizeof(obj, default)
    return _getsizeof_wrapper


try:  # str intern()
    _intern = intern
except NameError:  # no intern() in Python 3.0
    def _intern(val):
        return val


 # private functions

def _basicsize(t, base=0, heap=False, obj=None):
    '''Get non-zero basicsize of type,
       including the header sizes.
    '''
    s = max(getattr(t, '__basicsize__', 0), base)
     # include gc header size
    if t != _Type_type:
        h = getattr(t, '__flags__', 0) & _Py_TPFLAGS_HAVE_GC
    elif heap:  # type, allocated on heap
        h = True
    else:  # None has no __flags__ attr
        h = getattr(obj, '__flags__', 0) & _Py_TPFLAGS_HEAPTYPE
    if h:
        s += _sizeof_CPyGC_Head
     # include reference counters
    return s + _sizeof_Crefcounts


def _derive_typedef(typ):
    '''Return single, existing super type typedef or None.
    '''
    v = [v for v in _values(_typedefs) if _issubclass(typ, v.type)]
    if len(v) == 1:
        return v[0]
    return None


def _dir2(obj, pref='', excl=(), slots=None, itor=''):
    '''Return an attribute name, object 2-tuple for certain
       attributes or for the ``__slots__`` attributes of the
       given object, but not both.  Any iterator referent
       objects are returned with the given name if the
       latter is non-empty.
    '''
    if slots:  # __slots__ attrs
        if hasattr(obj, slots):
             # collect all inherited __slots__ attrs
             # from list, tuple, or dict __slots__,
             # while removing any duplicate attrs
            s = {}
            for c in type(obj).mro():
                for a in getattr(c, slots, ()):
                    if a.startswith('__'):
                        a = '_' + c.__name__ + a
                    if hasattr(obj, a):
                        s.setdefault(a, getattr(obj, a))
             # assume __slots__ tuple/list
             # is holding the attr values
            yield slots, _Slots(s)  # _keys(s)
            for t in _items(s):
                yield t  # attr name, value
    elif itor:  # iterator referents
        for o in obj:  # iter(obj)
            yield itor, o
    else:  # regular attrs
        for a in dir(obj):
            if a.startswith(pref) and a not in excl and hasattr(obj, a):
                yield a, getattr(obj, a)


def _infer_dict(obj):
    '''Return True for likely dict object.
    '''
    for ats in (('__len__', 'get', 'has_key', 'items', 'keys', 'values'),
                ('__len__', 'get', 'has_key', 'iteritems', 'iterkeys', 'itervalues')):
        if all(_callable(getattr(obj, a, None)) for a in ats):
            return True
    return False


def _isdictclass(obj):
    '''Return True for known dict objects.
    '''
    c = getattr(obj, '__class__', None)
    return c and c.__name__ in _dict_classes.get(c.__module__, ())


def _issubclass(sub, sup):
    '''Safe issubclass().
    '''
    if sup is not object:
        try:
            return issubclass(sub, sup)
        except TypeError:
            pass
    return False


# 'cell' is holding data used in closures
closure = (lambda x: (lambda: x))(None)
try:
    cell_type = type(closure.__closure__[0])
except AttributeError:  # Python 2.5
    cell_type = type(closure.func_closure[0])


def _iscell(obj):
    '''Return True if obj is a cell as used in a closure.'''
    return isinstance(obj, cell_type)


def _isnamedtuple(obj):
    '''Named tuples are identified via duck typing:
    http://www.gossamer-threads.com/lists/python/dev/1142178
    '''
    return isinstance(obj, tuple) and hasattr(obj, '_fields')


def _itemsize(t, item=0):
    '''Get non-zero itemsize of type.
    '''
     # replace zero value with default
    return getattr(t, '__itemsize__', 0) or item


def _kwdstr(**kwds):
    '''Keyword arguments as a string.
    '''
    return ', '.join(sorted('%s=%r' % kv for kv in _items(kwds)))


def _lengstr(obj):
    '''Object length as a string.
    '''
    n = leng(obj)
    if n is None:  # no len
        r = ''
    elif n > _len(obj):  # extended
        r = ' leng %d!' % n
    else:
        r = ' leng %d' % n
    return r


def _nameof(obj, dflt=''):
    '''Return the name of an object.
    '''
    return getattr(obj, '__name__', dflt)


def _objs_opts(objs, all=None, **opts):
    '''Return given or 'all' objects
       and the remaining options.
    '''
    if objs:  # given objects
        t = objs
    elif all in (False, None):
        t = ()
    elif all is True:  # 'all' objects ...
         # ... modules first, globals and stack
         # (may contain duplicate objects)
        t = tuple(_values(sys.modules)) + (
            globals(), stack(sys.getrecursionlimit())[2:])
    else:
        raise ValueError('invalid option: %s=%r' % ('all', all))
    return t, opts


def _p100(part, total, prec=1):
    '''Return percentage as string.
    '''
    r = float(total)
    if r:
        r = part * 100.0 / r
        return '%.*f%%' % (prec, r)
    return 'n/a'


def _plural(num):
    '''Return 's' if plural.
    '''
    if num == 1:
        s = ''
    else:
        s = 's'
    return s


def _power2(n):
    '''Find the next power of 2.
    '''
    p2 = 16
    while n > p2:
        p2 += p2
    return p2


def _prepr(obj, clip=0):
    '''Prettify and clip long repr() string.
    '''
    return _repr(obj, clip=clip).strip('<>').replace("'", '')  # remove <''>


def _printf(fmt, *args, **print3opts):
    '''Formatted print.
    '''
    if print3opts:  # like Python 3.0
        f = print3opts.get('file', None) or sys.stdout
        if args:
            f.write(fmt % args)
        else:
            f.write(fmt)
        f.write(print3opts.get('end', linesep))
    elif args:
        print(fmt % args)
    else:
        print(fmt)


def _refs(obj, named, *ats, **kwds):
    '''Return specific attribute objects of an object.
    '''
    if named:
        for a in ats:  # cf. inspect.getmembers()
            if hasattr(obj, a):
                yield _NamedRef(a, getattr(obj, a))
        if kwds:  # kwds are _dir2() args
            for a, o in _dir2(obj, **kwds):
                yield _NamedRef(a, o)
    else:
        for a in ats:  # cf. inspect.getmembers()
            if hasattr(obj, a):
                yield getattr(obj, a)
        if kwds:  # kwds are _dir2() args
            for _, o in _dir2(obj, **kwds):
                yield o


def _repr(obj, clip=80):
    '''Clip long repr() string.
    '''
    try:  # safe repr()
        r = repr(obj)
    except Exception:
        r = 'N/A'
    if 0 < clip < len(r):
        h = (clip // 2) - 2
        if h > 0:
            r = r[:h] + '....' + r[-h:]
    return r


def _SI(size, K=1024, i='i'):
    '''Return size as SI string.
    '''
    if 1 < K < size:
        f = float(size)
        for si in iter('KMGPTE'):
            f /= K
            if f < K:
                return ' or %.1f %s%sB' % (f, si, i)
    return ''


def _SI2(size, **kwds):
    '''Return size as regular plus SI string.
    '''
    return str(size) + _SI(size, **kwds)


 # type-specific referent functions

def _class_refs(obj, named):
    '''Return specific referents of a class object.
    '''
    return _refs(obj, named, '__class__', '__dict__', '__doc__', '__mro__',
                             '__name__', '__slots__', '__weakref__')


def _co_refs(obj, named):
    '''Return specific referents of a code object.
    '''
    return _refs(obj, named, pref='co_')


def _dict_refs(obj, named):
    '''Return key and value objects of a dict/proxy.
    '''
    if named:
        for k, v in _items(obj):
            s = str(k)
            yield _NamedRef('[K] ' + s, k)
            yield _NamedRef('[V] ' + s + ': ' + _repr(v), v)
    else:
        try:
            for k, v in _items(obj):
                yield k
                yield v
        except ReferenceError:
            warnings.warn("Reference error while iterating over '%s'" % str(obj.__class__))


def _enum_refs(obj, named):
    '''Return specific referents of an enumerate object.
    '''
    return _refs(obj, named, '__doc__')


def _exc_refs(obj, named):
    '''Return specific referents of an Exception object.
    '''
     # .message raises DeprecationWarning in Python 2.6
    return _refs(obj, named, 'args', 'filename', 'lineno', 'msg', 'text')  # , 'message', 'mixed'


def _file_refs(obj, named):
    '''Return specific referents of a file object.
    '''
    return _refs(obj, named, 'mode', 'name')


def _frame_refs(obj, named):
    '''Return specific referents of a frame object.
    '''
    return _refs(obj, named, pref='f_')


def _func_refs(obj, named):
    '''Return specific referents of a function or lambda object.
    '''
    return _refs(obj, named, '__doc__', '__name__', '__code__', '__closure__',
                 pref='func_', excl=('func_globals',))


def _cell_refs(obj, named):
    return _refs(obj, named, 'cell_contents')


def _namedtuple_refs(obj, named):
    '''Return slots but exclude dict
    '''
    return _refs(obj, named, '__class__', slots='__slots__')


def _gen_refs(obj, named):
    '''Return the referent(s) of a generator object.
    '''
     # only some gi_frame attrs
    f = getattr(obj, 'gi_frame', None)
    return _refs(f, named, 'f_locals', 'f_code')


def _im_refs(obj, named):
    '''Return specific referents of a method object.
    '''
    return _refs(obj, named, '__doc__', '__name__', '__code__', pref='im_')


def _inst_refs(obj, named):
    '''Return specific referents of a class instance.
    '''
    return _refs(obj, named, '__dict__', '__class__', slots='__slots__')


def _iter_refs(obj, named):
    '''Return the referent(s) of an iterator object.
    '''
    r = _getreferents(obj)  # special case
    return _refs(r, named, itor=_nameof(obj) or 'iteref')


def _module_refs(obj, named):
    '''Return specific referents of a module object.
    '''
     # ignore this very module
    if obj.__name__ == __name__:
        return ()
     # module is essentially a dict
    return _dict_refs(obj.__dict__, named)


def _prop_refs(obj, named):
    '''Return specific referents of a property object.
    '''
    return _refs(obj, named, '__doc__', pref='f')


def _seq_refs(obj, unused):  # named unused for PyChecker
    '''Return specific referents of a frozen/set, list, tuple and xrange object.
    '''
    return obj  # XXX for r in obj: yield r


def _stat_refs(obj, named):
    '''Return referents of a os.stat object.
    '''
    return _refs(obj, named, pref='st_')


def _statvfs_refs(obj, named):
    '''Return referents of a os.statvfs object.
    '''
    return _refs(obj, named, pref='f_')


def _tb_refs(obj, named):
    '''Return specific referents of a traceback object.
    '''
    return _refs(obj, named, pref='tb_')


def _type_refs(obj, named):
    '''Return specific referents of a type object.
    '''
    return _refs(obj, named, '__dict__', '__doc__', '__mro__',
                             '__name__', '__slots__', '__weakref__')


def _weak_refs(obj, unused):  # named unused for PyChecker
    '''Return weakly referent object.
    '''
    try:  # ignore 'key' of KeyedRef
        return (obj(),)
    except:  # XXX ReferenceError
        return ()


_all_refs = (None, _cell_refs, _class_refs, _co_refs, _dict_refs, _enum_refs,
             _exc_refs, _file_refs, _frame_refs, _func_refs, _gen_refs,
             _im_refs, _inst_refs, _iter_refs, _module_refs, _namedtuple_refs,
             _prop_refs, _seq_refs, _stat_refs, _statvfs_refs, _tb_refs,
             _type_refs, _weak_refs)


 # type-specific length functions

def _len(obj):
    '''Safe len().
    '''
    try:
        return len(obj)
    except TypeError:  # no len()
        return 0


def _len_array(obj):
    '''Array length in bytes.
    '''
    return len(obj) * obj.itemsize


def _len_bytearray(obj):
    '''Bytearray size.
    '''
    return obj.__alloc__()


def _len_code(obj):  # see .../Lib/test/test_sys.py
    '''Length of code object (stack and variables only).
    '''
    return (obj.co_stacksize + obj.co_nlocals + _len(obj.co_freevars) +
            _len(obj.co_cellvars) - 1)


def _len_dict(obj):
    '''Dict length in items (estimate).
    '''
    n = len(obj)  # active items
    if n < 6:  # ma_smalltable ...
        n = 0  # ... in basicsize
    else:  # at least one unused
        n = _power2(n + 1)
    return n


def _len_frame(obj):
    '''Length of a frame object.
    '''
    c = getattr(obj, 'f_code', None)
    if c:
        n = _len_code(c)
    else:
        n = 0
    return n


_digit2p2 = 1 << (_sizeof_Cdigit << 3)
_digitmax = _digit2p2 - 1  # == (2 * PyLong_MASK + 1)
_digitlog = 1.0 / log(_digit2p2)


def _len_int(obj):
    '''Length of multi-precision int (aka long) in digits.
    '''
    if obj:
        n, i = 1, abs(obj)
        if i > _digitmax:
             # no log(x[, base]) in Python 2.2
            n += int(log(i) * _digitlog)
    else:  # zero
        n = 0
    return n


def _len_iter(obj):
    '''Length (hint) of an iterator.
    '''
    n = getattr(obj, '__length_hint__', None)
    if n:
        n = n()
    else:  # try len()
        n = _len(obj)
    return n


def _len_list(obj):
    '''Length of list (estimate).
    '''
    n = len(obj)
     # estimate over-allocation
    if n > 8:
        n += 6 + (n >> 3)
    elif n:
        n += 4
    return n


def _len_module(obj):
    '''Module length.
    '''
    return _len(obj.__dict__)  # _len(dir(obj))


def _len_set(obj):
    '''Length of frozen/set (estimate).
    '''
    n = len(obj)
    if n > 8:  # assume half filled
        n = _power2(n + n - 2)
    elif n:  # at least 8
        n = 8
    return n


def _len_slice(obj):
    '''Slice length.
    '''
    try:
        return ((obj.stop - obj.start + 1) // obj.step)
    except (AttributeError, TypeError):
        return 0


def _len_slots(obj):
    '''Slots length.
    '''
    return len(obj) - 1


def _len_struct(obj):
    '''Struct length in bytes.
    '''
    try:
        return obj.size
    except AttributeError:
        return 0


def _len_unicode(obj):
    '''Unicode size.
    '''
    return len(obj) + 1


_all_lengs = (None, _len, _len_array, _len_bytearray, _len_code, _len_dict,
              _len_frame, _len_int, _len_iter, _len_list, _len_module,
              _len_set, _len_slice, _len_slots, _len_struct, _len_unicode)


# more private functions and classes

_old_style = '*'  # marker
_new_style = ''   # no marker


class _Claskey(object):
    '''Wrapper for class objects.
    '''
    __slots__ = ('_obj', '_sty')

    def __init__(self, obj, style):
        self._obj = obj  # XXX Weakref.ref(obj)
        self._sty = style

    def __str__(self):
        r = str(self._obj)
        if r.endswith('>'):
            r = '%s%s def>' % (r[:-1], self._sty)
        elif self._sty is _old_style and not r.startswith('class '):
            r = 'class %s%s def' % (r, self._sty)
        else:
            r = '%s%s def' % (r, self._sty)
        return r
    __repr__ = __str__

 # For most objects, the object type is used as the key in the
 # _typedefs dict further below, except class and type objects
 # and old-style instances.  Those are wrapped with separate
 # _Claskey or _Instkey instances to be able (1) to distinguish
 # instances of different old-style classes by class, (2) to
 # distinguish class (and type) instances from class (and type)
 # definitions for new-style classes and (3) provide similar
 # results for repr() and str() of new- and old-style classes
 # and instances.

_claskeys = {}  # [id(obj)] = _Claskey()


def _claskey(obj, style):
    '''Wrap an old- or new-style class object.
    '''
    i = id(obj)
    k = _claskeys.get(i, None)
    if not k:
        _claskeys[i] = k = _Claskey(obj, style)
    return k

try:  # no Class- and InstanceType in Python 3.0
    _Types_ClassType = Types.ClassType
    _Types_InstanceType = Types.InstanceType

    class _Instkey(object):
        '''Wrapper for old-style class (instances).
        '''
        __slots__ = ('_obj',)

        def __init__(self, obj):
            self._obj = obj  # XXX Weakref.ref(obj)

        def __str__(self):
            return '<class %s.%s%s>' % (self._obj.__module__, self._obj.__name__, _old_style)
        __repr__ = __str__

    _instkeys = {}  # [id(obj)] = _Instkey()

    def _instkey(obj):
        '''Wrap an old-style class (instance).
        '''
        i = id(obj)
        k = _instkeys.get(i, None)
        if not k:
            _instkeys[i] = k = _Instkey(obj)
        return k

    def _keytuple(obj):
        '''Return class and instance keys for a class.
        '''
        t = type(obj)
        if t is _Types_InstanceType:
            t = obj.__class__
            return _claskey(t, _old_style), _instkey(t)
        elif t is _Types_ClassType:
            return _claskey(obj, _old_style), _instkey(obj)
        elif t is _Type_type:
            return _claskey(obj, _new_style), obj
        return None, None  # not a class

    def _objkey(obj):
        '''Return the key for any object.
        '''
        k = type(obj)
        if k is _Types_InstanceType:
            k = _instkey(obj.__class__)
        elif k is _Types_ClassType:
            k = _claskey(obj, _old_style)
        elif k is _Type_type:
            k = _claskey(obj, _new_style)
        return k

except AttributeError:  # Python 3.0

    def _keytuple(obj):
        '''Return class and instance keys for a class.
        '''
        if type(obj) is _Type_type:  # isclass(obj):
            return _claskey(obj, _new_style), obj
        return None, None  # not a class

    def _objkey(obj):
        '''Return the key for any object.
        '''
        k = type(obj)
        if k is _Type_type:  # isclass(obj):
            k = _claskey(obj, _new_style)
        return k


class _NamedRef(object):
    '''Store referred object along
       with the name of the referent.
    '''
    __slots__ = ('name', 'ref')

    def __init__(self, name, ref):
        self.name = name
        self.ref = ref


class _Slots(tuple):
    '''Wrapper class for __slots__ attribute at
       class instances to account for the size
       of the __slots__ tuple/list containing
       references to the attribute values.
    '''
    pass


 # kinds of _Typedefs
_i = _intern
_all_kinds = (_kind_static, _kind_dynamic, _kind_derived, _kind_ignored, _kind_inferred) = (
    _i('static'), _i('dynamic'), _i('derived'), _i('ignored'), _i('inferred'))
del _i


class _Typedef(object):
    '''Type definition class.
    '''
    __slots__ = {
        'base': 0,     # basic size in bytes
        'item': 0,     # item size in bytes
        'leng': None,  # or _len_...() function
        'refs': None,  # or _..._refs() function
        'both': None,  # both data and code if True, code only if False
        'kind': None,  # _kind_... value
        'type': None}  # original type

    def __init__(self, **kwds):
        self.reset(**kwds)

    def __lt__(self, unused):  # for Python 3.0
        return True

    def __repr__(self):
        return repr(self.args())

    def __str__(self):
        t = [str(self.base), str(self.item)]
        for f in (self.leng, self.refs):
            if f:
                t.append(f.__name__)
            else:
                t.append('n/a')
        if not self.both:
            t.append('(code only)')
        return ', '.join(t)

    def args(self):  # as args tuple
        '''Return all attributes as arguments tuple.
        '''
        return (self.base, self.item, self.leng, self.refs,
                self.both, self.kind, self.type)

    def dup(self, other=None, **kwds):
        '''Duplicate attributes of dict or other typedef.
        '''
        if other is None:
            d = _dict_typedef.kwds()
        else:
            d = other.kwds()
        d.update(kwds)
        self.reset(**d)

    def flat(self, obj, mask=0):
        '''Return the aligned flat size.
        '''
        s = self.base
        if self.leng and self.item > 0:  # include items
            s += self.leng(obj) * self.item
        if _getsizeof:  # _getsizeof prevails
            s = _getsizeof(obj, s)
        if mask:  # align
            s = (s + mask) & ~mask
        return s

    def format(self):
        '''Return format dict.
        '''
        c = n = ''
        if not self.both:
            c = ' (code only)'
        if self.leng:
            n = ' (%s)' % _nameof(self.leng)
        return dict(base=self.base, item=self.item, leng=n, code=c,
                    kind=self.kind)

    def kwds(self):
        '''Return all attributes as keywords dict.
        '''
        return dict(base=self.base, item=self.item,
                    leng=self.leng, refs=self.refs,
                    both=self.both, kind=self.kind, type=self.type)

    def save(self, t, base=0, heap=False):
        '''Save this typedef plus its class typedef.
        '''
        c, k = _keytuple(t)
        if k and k not in _typedefs:  # instance key
            _typedefs[k] = self
            if c and c not in _typedefs:  # class key
                if t.__module__ in _builtin_modules:
                    k = _kind_ignored  # default
                else:
                    k = self.kind
                _typedefs[c] = _Typedef(base=_basicsize(type(t), base=base, heap=heap),
                                        refs=_type_refs,
                                        both=False, kind=k, type=t)
        elif isbuiltin(t) and t not in _typedefs:  # array, range, xrange in Python 2.x
            _typedefs[t] = _Typedef(base=_basicsize(t, base=base),
                                    both=False, kind=_kind_ignored, type=t)
        else:
            raise KeyError('asizeof typedef %r bad: %r %r' % (self, (c, k), self.both))

    def set(self, safe_len=False, **kwds):
        '''Set one or more attributes.
        '''
        if kwds:  # double check
            d = self.kwds()
            d.update(kwds)
            self.reset(**d)
        if safe_len and self.item:
            self.leng = _len

    def reset(self, base=0, item=0, leng=None, refs=None,
              both=True, kind=None, type=None):
        '''Reset all specified attributes.
        '''
        if base < 0:
            raise ValueError('invalid option: %s=%r' % ('base', base))
        else:
            self.base = base
        if item < 0:
            raise ValueError('invalid option: %s=%r' % ('item', item))
        else:
            self.item = item
        if leng in _all_lengs:  # XXX or _callable(leng)
            self.leng = leng
        else:
            raise ValueError('invalid option: %s=%r' % ('leng', leng))
        if refs in _all_refs:  # XXX or _callable(refs)
            self.refs = refs
        else:
            raise ValueError('invalid option: %s=%r' % ('refs', refs))
        if both in (False, True):
            self.both = both
        else:
            raise ValueError('invalid option: %s=%r' % ('both', both))
        if kind in _all_kinds:
            self.kind = kind
        else:
            raise ValueError('invalid option: %s=%r' % ('kind', kind))
        self.type = type


_typedefs = {}  # [key] = _Typedef()


def _typedef_both(t, base=0, item=0, leng=None, refs=None, kind=_kind_static, heap=False):
    '''Add new typedef for both data and code.
    '''
    v = _Typedef(base=_basicsize(t, base=base), item=_itemsize(t, item),
                 refs=refs, leng=leng,
                 both=True, kind=kind, type=t)
    v.save(t, base=base, heap=heap)
    return v  # for _dict_typedef


def _typedef_code(t, base=0, refs=None, kind=_kind_static, heap=False):
    '''Add new typedef for code only.
    '''
    v = _Typedef(base=_basicsize(t, base=base),
                 refs=refs,
                 both=False, kind=kind, type=t)
    v.save(t, base=base, heap=heap)
    return v  # for _dict_typedef

 # static typedefs for data and code types
_typedef_both(complex)
_typedef_both(float)
_typedef_both(list, refs=_seq_refs, leng=_len_list, item=_sizeof_Cvoidp)  # sizeof(PyObject*)
_typedef_both(tuple, refs=_seq_refs, leng=_len, item=_sizeof_Cvoidp)  # sizeof(PyObject*)
_typedef_both(property, refs=_prop_refs)
_typedef_both(type(Ellipsis))
_typedef_both(type(None))

 # _Slots is a special tuple, see _Slots.__doc__
_typedef_both(_Slots, item=_sizeof_Cvoidp,
              leng=_len_slots,  # length less one
              refs=None,  # but no referents
              heap=True)  # plus head

 # dict, dictproxy, dict_proxy and other dict-like types
_dict_typedef = _typedef_both(dict, item=_sizeof_CPyDictEntry, leng=_len_dict, refs=_dict_refs)
try:  # <type dictproxy> only in Python 2.x
    _typedef_both(Types.DictProxyType, item=_sizeof_CPyDictEntry, leng=_len_dict, refs=_dict_refs)
except AttributeError:  # XXX any class __dict__ is <type dict_proxy> in Python 3.0?
    _typedef_both(type(_Typedef.__dict__), item=_sizeof_CPyDictEntry, leng=_len_dict, refs=_dict_refs)
 # other dict-like classes and types may be derived or inferred,
 # provided the module and class name is listed here (see functions
 # adict, _isdictclass and _infer_dict for further details)
_dict_classes = {'UserDict': ('IterableUserDict', 'UserDict'),
                 'weakref': ('WeakKeyDictionary', 'WeakValueDictionary')}
try:  # <type module> is essentially a dict
    _typedef_both(Types.ModuleType, base=_dict_typedef.base,
                  item=_dict_typedef.item + _sizeof_CPyModuleObject,
                  leng=_len_module, refs=_module_refs)
except AttributeError:  # missing
    pass

 # newer or obsolete types
try:
    from array import array  # array type
    _typedef_both(array, leng=_len_array, item=_sizeof_Cbyte)
    if _getsizeof_bugs:
        _getsizeof = _getsizeof_exclude(_getsizeof, array)
except ImportError:  # missing
    pass

try:  # bool has non-zero __itemsize__ in 3.0
    _typedef_both(bool)
except NameError:  # missing
    pass

try:  # ignore basestring
    _typedef_both(basestring, leng=None)
except NameError:  # missing
    pass

try:
    if isbuiltin(buffer):  # Python 2.2
        _typedef_both(type(buffer('')), item=_sizeof_Cbyte, leng=_len)  # XXX len in bytes?
    else:
        _typedef_both(buffer, item=_sizeof_Cbyte, leng=_len)  # XXX len in bytes?
except NameError:  # missing
    pass

try:
    _typedef_both(bytearray, item=_sizeof_Cbyte, leng=_len_bytearray)
except NameError:  # bytearray new in 2.6, 3.0
    pass
try:
    if type(bytes) is not type(str):  # bytes is str in 2.6, bytes new in 2.6, 3.0
        _typedef_both(bytes, item=_sizeof_Cbyte, leng=_len)  # bytes new in 2.6, 3.0
except NameError:  # missing
    pass
try:  # XXX like bytes
    _typedef_both(str8, item=_sizeof_Cbyte, leng=_len)  # str8 new in 2.6, 3.0
except NameError:  # missing
    pass

try:
    _typedef_both(enumerate, refs=_enum_refs)
except NameError:  # missing
    pass

try:  # Exception is type in Python 3.0
    _typedef_both(Exception, refs=_exc_refs)
except:  # missing
    pass

try:
    _typedef_both(file, refs=_file_refs)
except NameError:  # missing
    pass

try:
    _typedef_both(frozenset, item=_sizeof_Csetentry, leng=_len_set, refs=_seq_refs)
except NameError:  # missing
    pass
try:
    _typedef_both(set, item=_sizeof_Csetentry, leng=_len_set, refs=_seq_refs)
except NameError:  # missing
    pass

try:  # not callable()
    _typedef_both(Types.GetSetDescriptorType)
except AttributeError:  # missing
    pass

try:  # if long exists, it is multi-precision ...
    _typedef_both(long, item=_sizeof_Cdigit, leng=_len_int)
    _typedef_both(int)  # ... and int is fixed size
except NameError:  # no long, only multi-precision int in Python 3.0
    _typedef_both(int, item=_sizeof_Cdigit, leng=_len_int)

try:  # not callable()
    _typedef_both(Types.MemberDescriptorType)
except AttributeError:  # missing
    pass

try:
    _typedef_both(type(NotImplemented))  # == Types.NotImplementedType
except NameError:  # missing
    pass

try:
    _typedef_both(range)
except NameError:  # missing
    pass
try:
    _typedef_both(xrange)
except NameError:  # missing
    pass

try:
    _typedef_both(reversed, refs=_enum_refs)
except NameError:  # missing
    pass

try:
    _typedef_both(slice, item=_sizeof_Cvoidp, leng=_len_slice)  # XXX worst-case itemsize?
except NameError:  # missing
    pass

try:
    from os import stat
    _typedef_both(type(stat(curdir)), refs=_stat_refs)     # stat_result
except ImportError:  # missing
    pass

try:
    from os import statvfs
    _typedef_both(type(statvfs(curdir)), refs=_statvfs_refs,  # statvfs_result
                  item=_sizeof_Cvoidp, leng=_len)
except ImportError:  # missing
    pass

try:
    from struct import Struct  # only in Python 2.5 and 3.0
    _typedef_both(Struct, item=_sizeof_Cbyte, leng=_len_struct)  # len in bytes
except ImportError:  # missing
    pass

try:
    _typedef_both(Types.TracebackType, refs=_tb_refs)
except AttributeError:  # missing
    pass

try:
    _typedef_both(unicode, leng=_len_unicode, item=_sizeof_Cunicode)
    _typedef_both(str, leng=_len, item=_sizeof_Cbyte)  # 1-byte char
except NameError:  # str is unicode
    _typedef_both(str, leng=_len_unicode, item=_sizeof_Cunicode)

try:  # <type 'KeyedRef'>
    _typedef_both(Weakref.KeyedRef, refs=_weak_refs, heap=True)  # plus head
except AttributeError:  # missing
    pass


try:  # <type 'weakproxy'>
    _typedef_both(Weakref.ProxyType)
except AttributeError:  # missing
    pass

try:  # <type 'weakref'>
    _typedef_both(Weakref.ReferenceType, refs=_weak_refs)
except AttributeError:  # missing
    pass

 # some other, callable types
_typedef_code(object, kind=_kind_ignored)
_typedef_code(super, kind=_kind_ignored)
_typedef_code(_Type_type, kind=_kind_ignored)

try:
    _typedef_code(classmethod, refs=_im_refs)
except NameError:
    pass
try:
    _typedef_code(staticmethod, refs=_im_refs)
except NameError:
    pass
try:
    _typedef_code(Types.MethodType, refs=_im_refs)
except NameError:
    pass

try:  # generator, code only, no len(), not callable()
    _typedef_code(Types.GeneratorType, refs=_gen_refs)
except AttributeError:  # missing
    pass

try:  # <type 'weakcallableproxy'>
    _typedef_code(Weakref.CallableProxyType, refs=_weak_refs)
except AttributeError:  # missing
    pass

 # any type-specific iterators
s = [_items({}), _keys({}), _values({})]
try:  # reversed list and tuples iterators
    s.extend([reversed([]), reversed(())])
except NameError:  # missing
    pass
try:  # range iterator
    s.append(xrange(1))
except NameError:  # missing
    pass
try:  # callable-iterator
    from re import finditer
    s.append(finditer('', ''))
except ImportError:  # missing
    pass
for t in _values(_typedefs):
    if t.type and t.leng:
        try:  # create an (empty) instance
            s.append(t.type())
        except TypeError:
            pass
for t in s:
    try:
        i = iter(t)
        _typedef_both(type(i), leng=_len_iter, refs=_iter_refs, item=0)  # no itemsize!
    except (KeyError, TypeError):  # ignore non-iterables, duplicates, etc.
        pass
del i, s, t


def _typedef(obj, derive=False, infer=False):
    '''Create a new typedef for an object.
    '''
    t = type(obj)
    v = _Typedef(base=_basicsize(t, obj=obj),
                 kind=_kind_dynamic, type=t)
  ##_printf('new %r %r/%r %s', t, _basicsize(t), _itemsize(t), _repr(dir(obj)))
    if ismodule(obj):  # handle module like dict
        v.dup(item=_dict_typedef.item + _sizeof_CPyModuleObject,
              leng=_len_module,
              refs=_module_refs)
    elif isframe(obj):
        v.set(base=_basicsize(t, base=_sizeof_CPyFrameObject, obj=obj),
              item=_itemsize(t),
              leng=_len_frame,
              refs=_frame_refs)
    elif iscode(obj):
        v.set(base=_basicsize(t, base=_sizeof_CPyCodeObject, obj=obj),
              item=_sizeof_Cvoidp,
              leng=_len_code,
              refs=_co_refs,
              both=False)  # code only
    elif _callable(obj):
        if isclass(obj):  # class or type
            v.set(refs=_class_refs,
                  both=False)  # code only
            if getattr(obj, '__module__', None) in _builtin_modules:
                v.set(kind=_kind_ignored)
        elif isbuiltin(obj):  # function or method
            v.set(both=False,  # code only
                  kind=_kind_ignored)
        elif isfunction(obj):
            v.set(refs=_func_refs,
                  both=False)  # code only
        elif ismethod(obj):
            v.set(refs=_im_refs,
                  both=False)  # code only
        elif isclass(t):  # callable instance, e.g. SCons,
             # handle like any other instance further below
            v.set(item=_itemsize(t), safe_len=True,
                  refs=_inst_refs)  # not code only!
        else:
            v.set(both=False)  # code only
    elif _issubclass(t, dict):
        v.dup(kind=_kind_derived)
    elif _isdictclass(obj) or (infer and _infer_dict(obj)):
        v.dup(kind=_kind_inferred)
    elif _iscell(obj):
        v.set(item=_itemsize(t), refs=_cell_refs)
    elif _isnamedtuple(obj):
        v.set(refs=_namedtuple_refs)
    elif getattr(obj, '__module__', None) in _builtin_modules:
        v.set(kind=_kind_ignored)
    else:  # assume an instance of some class
        if derive:
            p = _derive_typedef(t)
            if p:  # duplicate parent
                v.dup(other=p, kind=_kind_derived)
                return v
        if _issubclass(t, Exception):
            v.set(item=_itemsize(t), safe_len=True,
                  refs=_exc_refs,
                  kind=_kind_derived)
        elif isinstance(obj, Exception):
            v.set(item=_itemsize(t), safe_len=True,
                  refs=_exc_refs)
        else:
            v.set(item=_itemsize(t), safe_len=True,
                  refs=_inst_refs)
    return v


class _Prof(object):
    '''Internal type profile class.
    '''
    total = 0     # total size
    high = 0     # largest size
    number = 0     # number of (unique) objects
    objref = None  # largest object (weakref)
    weak = False # objref is weakref(object)

    def __cmp__(self, other):
        if self.total < other.total:
            return -1
        if self.total > other.total:
            return +1
        if self.number < other.number:
            return -1
        if self.number > other.number:
            return +1
        return 0

    def __lt__(self, other):  # for Python 3.0
        return self.__cmp__(other) < 0

    def format(self, clip=0, grand=None):
        '''Return format dict.
        '''
        if self.number > 1:  # avg., plural
            a, p = int(self.total / self.number), 's'
        else:
            a, p = self.total, ''
        o = self.objref
        if self.weak:  # weakref'd
            o = o()
        t = _SI2(self.total)
        if grand:
            t += ' (%s)' % _p100(self.total, grand, prec=0)
        return dict(avg=_SI2(a), high=_SI2(self.high),
                    lengstr=_lengstr(o), obj=_repr(o, clip=clip),
                    plural=p, total=t)

    def update(self, obj, size):
        '''Update this profile.
        '''
        self.number += 1
        self.total += size
        if self.high < size:  # largest
            self.high = size
            try:  # prefer using weak ref
                self.objref, self.weak = Weakref.ref(obj), True
            except TypeError:
                self.objref, self.weak = obj, False


 # public classes

class Asized(object):
    '''Store the results of an **asized** object
       in these 4 attributes:

         *size*  -- total size of the object

         *flat*  -- flat size of the object

         *name*  -- name or ``repr`` of the object

         *refs*  -- tuple containing an **Asized** instance for each referent
    '''
    def __init__(self, size, flat, refs=(), name=None):
        self.size = size  # total size
        self.flat = flat  # flat size
        self.name = name  # name, repr or None
        self.refs = tuple(refs)

    def __str__(self):
        return 'size %r, flat %r, refs[%d], name %r' % (
            self.size, self.flat, len(self.refs), self.name)

    def get(self, name):
        for ref in self.refs:
            if name == ref.name:
                return ref
        return None

    def format(self, format='%(name)s size=%(size)d flat=%(flat)d', depth=-1,
               order_by='size', indent=''):
        '''
        Format the size information of the object and of all sized referents as
        a string.

        :param format: Specifies the format per instance with 'name', 'size'
            and 'flat' as valid interpolation parameters.
        :param depth: Up to which recursion level the referents are printed.
        :param order_by: Control sort order of referents. Valid options are
            'name', 'size' and 'flat'.
        '''
        representation = indent + (format % self.__dict__)
        if depth != 0:
            indent = indent + '    '
            reverse = (order_by in ('size', 'flat'))
            refs = sorted(self.refs, key=lambda x: getattr(x, order_by), reverse=reverse)
            refs = [ref.format(format, depth-1, order_by, indent)
                    for ref in refs]
            representation = '\n'.join([representation] + refs)
        return representation


class Asizer(object):
    '''Sizer state and options.
    '''
    _align_ = 8
    _clip_ = 80
    _code_ = False
    _derive_ = False
    _detail_ = 0  # for Asized only
    _infer_ = False
    _limit_ = 100
    _stats_ = 0

    _cutoff = 0  # in percent
    _depth = 0  # recursion depth
    _duplicate = 0
    _excl_d = None  # {}
    _ign_d = _kind_ignored
    _incl = ''  # or ' (incl. code)'
    _mask = 7   # see _align_
    _missed = 0   # due to errors
    _profile = False
    _profs = None  # {}
    _seen = None  # {}
    _total = 0   # total size

    _stream = None  # IO stream for printing

    def __init__(self, **opts):
        '''See method **reset** for the available options.
        '''
        self._excl_d = {}
        self.reset(**opts)

    def _printf(self, *args, **kwargs):
        '''Print to configured stream if any is specified and the file argument
        is not already set for this specific call.
        '''
        if self._stream and not kwargs.get('file'):
            kwargs['file'] = self._stream
        _printf(*args, **kwargs)

    def _clear(self):
        '''Clear state.
        '''
        self._depth = 0   # recursion depth
        self._duplicate = 0
        self._incl = ''  # or ' (incl. code)'
        self._missed = 0   # due to errors
        self._profile = False
        self._profs = {}
        self._seen = {}
        self._total = 0   # total size
        for k in _keys(self._excl_d):
            self._excl_d[k] = 0

    def _nameof(self, obj):
        '''Return the object's name.
        '''
        return _nameof(obj, '') or self._repr(obj)

    def _prepr(self, obj):
        '''Like **prepr()**.
        '''
        return _prepr(obj, clip=self._clip_)

    def _prof(self, key):
        '''Get _Prof object.
        '''
        p = self._profs.get(key, None)
        if not p:
            self._profs[key] = p = _Prof()
        return p

    def _repr(self, obj):
        '''Like ``repr()``.
        '''
        return _repr(obj, clip=self._clip_)

    def _sizer(self, obj, deep, sized):
        '''Size an object, recursively.
        '''
        s, f, i = 0, 0, id(obj)
         # skip obj if seen before
         # or if ref of a given obj
        if i in self._seen:
            if deep:
                self._seen[i] += 1
                if sized:
                    s = sized(s, f, name=self._nameof(obj))
                return s
        else:
            self._seen[i] = 0
        try:
            k, rs = _objkey(obj), []
            if k in self._excl_d:
                self._excl_d[k] += 1
            else:
                v = _typedefs.get(k, None)
                if not v:  # new typedef
                    _typedefs[k] = v = _typedef(obj, derive=self._derive_,
                                                infer=self._infer_)
                if (v.both or self._code_) and v.kind is not self._ign_d:
                    s = f = v.flat(obj, self._mask)  # flat size
                    if self._profile:  # profile type
                        self._prof(k).update(obj, s)
                     # recurse, but not for nested modules
                    if v.refs and deep < self._limit_ and not (deep and ismodule(obj)):
                         # add sizes of referents
                        r, z, d = v.refs, self._sizer, deep + 1
                        if sized and deep < self._detail_:
                             # use named referents
                            for o in r(obj, True):
                                if isinstance(o, _NamedRef):
                                    t = z(o.ref, d, sized)
                                    t.name = o.name
                                else:
                                    t = z(o, d, sized)
                                    t.name = self._nameof(o)
                                rs.append(t)
                                s += t.size
                        else:  # no sum(<generator_expression>) in Python 2.2
                            for o in r(obj, False):
                                s += z(o, d, None)
                         # recursion depth
                        if self._depth < d:
                            self._depth = d
            self._seen[i] += 1
        except RuntimeError:  # XXX RecursionLimitExceeded:
            self._missed += 1
        if sized:
            s = sized(s, f, name=self._nameof(obj), refs=rs)
        return s

    def _sizes(self, objs, sized=None):
        '''Return the size or an **Asized** instance for each
           given object and the total size.  The total
           includes the size of duplicates only once.
        '''
        self.exclude_refs(*objs)  # skip refs to objs
        s, t = {}, []
        for o in objs:
            i = id(o)
            if i in s:  # duplicate
                self._seen[i] += 1
                self._duplicate += 1
            else:
                s[i] = self._sizer(o, 0, sized)
            t.append(s[i])
        if sized:
            s = sum(i.size for i in _values(s))
        else:
            s = sum(_values(s))
        self._total += s  # accumulate
        return s, tuple(t)

    def asized(self, *objs, **opts):
        '''Size each object and return an **Asized** instance with
           size information and referents up to the given detail
           level (and with modified options, see method **set**).

           If only one object is given, the return value is the
           **Asized** instance for that object.
        '''
        if opts:
            self.set(**opts)
        _, t = self._sizes(objs, Asized)
        if len(t) == 1:
            t = t[0]
        return t

    def asizeof(self, *objs, **opts):
        '''Return the combined size of the given objects
           (with modified options, see method **set**).
        '''
        if opts:
            self.set(**opts)
        s, _ = self._sizes(objs, None)
        return s

    def asizesof(self, *objs, **opts):
        '''Return the individual sizes of the given objects
           (with modified options, see method  **set**).
        '''
        if opts:
            self.set(**opts)
        _, t = self._sizes(objs, None)
        return t

    def exclude_refs(self, *objs):
        '''Exclude any references to the specified objects from sizing.

           While any references to the given objects are excluded, the
           objects will be sized if specified as positional arguments
           in subsequent calls to methods **asizeof** and **asizesof**.
        '''
        for o in objs:
            self._seen.setdefault(id(o), 0)

    def exclude_types(self, *objs):
        '''Exclude the specified object instances and types from sizing.

           All instances and types of the given objects are excluded,
           even objects specified as positional arguments in subsequent
           calls to methods **asizeof** and **asizesof**.
        '''
        for o in objs:
            for t in _keytuple(o):
                if t and t not in self._excl_d:
                    self._excl_d[t] = 0

    def print_profiles(self, w=0, cutoff=0, **print3opts):
        '''Print the profiles above *cutoff* percentage.

               *w=0*           -- indentation for each line

               *cutoff=0*      -- minimum percentage printed

               *print3options* -- print options, ala Python 3.0
        '''
         # get the profiles with non-zero size or count
        t = [(v, k) for k, v in _items(self._profs) if v.total > 0 or v.number > 1]
        if (len(self._profs) - len(t)) < 9:  # just show all
            t = [(v, k) for k, v in _items(self._profs)]
        if t:
            s = ''
            if self._total:
                s = ' (% of grand total)'
                c = max(cutoff, self._cutoff)
                c = int(c * 0.01 * self._total)
            else:
                c = 0
            self._printf('%s%*d profile%s:  total%s, average, and largest flat size%s:  largest object',
                         linesep, w, len(t), _plural(len(t)), s, self._incl, **print3opts)
            r = len(t)
            for v, k in sorted(t, reverse=True):
                s = 'object%(plural)s:  %(total)s, %(avg)s, %(high)s:  %(obj)s%(lengstr)s' % v.format(self._clip_, self._total)
                self._printf('%*d %s %s', w, v.number, self._prepr(k), s, **print3opts)
                r -= 1
                if r > 1 and v.total < c:
                    c = max(cutoff, self._cutoff)
                    self._printf('%+*d profiles below cutoff (%.0f%%)', w, r, c)
                    break
            z = len(self._profs) - len(t)
            if z > 0:
                self._printf('%+*d %r object%s', w, z, 'zero', _plural(z), **print3opts)

    def print_stats(self, objs=(), opts={}, sized=(), sizes=(), stats=3.0, **print3opts):
        '''Print the statistics.

               *w=0*           -- indentation for each line

               *objs=()*       -- optional, list of objects

               *opts={}*       -- optional, dict of options used

               *sized=()*      -- optional, tuple of **Asized** instances returned

               *sizes=()*      -- optional, tuple of sizes returned

               *stats=0.0*     -- print stats, see function **asizeof**

               *print3options* -- print options, as in Python 3.0
        '''
        s = min(opts.get('stats', stats) or 0, self._stats_)
        if s > 0:  # print stats
            t = self._total + self._missed + sum(_values(self._seen))
            w = len(str(t)) + 1
            t = c = ''
            o = _kwdstr(**opts)
            if o and objs:
                c = ', '
             # print header line(s)
            if sized and objs:
                n = len(objs)
                if n > 1:
                    self._printf('%sasized(...%s%s) ...', linesep, c, o, **print3opts)
                    for i in range(n):  # no enumerate in Python 2.2.3
                        self._printf('%*d: %s', w - 1, i, sized[i], **print3opts)
                else:
                    self._printf('%sasized(%s): %s', linesep, o, sized, **print3opts)
            elif sizes and objs:
                self._printf('%sasizesof(...%s%s) ...', linesep, c, o, **print3opts)
                for z, o in zip(sizes, objs):
                    self._printf('%*d bytes%s%s:  %s', w, z, _SI(z), self._incl, self._repr(o), **print3opts)
            else:
                if objs:
                    t = self._repr(objs)
                self._printf('%sasizeof(%s%s%s) ...', linesep, t, c, o, **print3opts)
             # print summary
            self.print_summary(w=w, objs=objs, **print3opts)
            if s > 1:  # print profile
                c = int(s - int(s)) * 100
                self.print_profiles(w=w, cutoff=c, **print3opts)
                if s > 2:  # print typedefs
                    self.print_typedefs(w=w, **print3opts)

    def print_summary(self, w=0, objs=(), **print3opts):
        '''Print the summary statistics.

               *w=0*            -- indentation for each line

               *objs=()*        -- optional, list of objects

               *print3options*  -- print options, as in Python 3.0
        '''
        self._printf('%*d bytes%s%s', w, self._total, _SI(self._total), self._incl, **print3opts)
        if self._mask:
            self._printf('%*d byte aligned', w, self._mask + 1, **print3opts)
        self._printf('%*d byte sizeof(void*)', w, _sizeof_Cvoidp, **print3opts)
        n = len(objs or ())
        if n > 0:
            d = self._duplicate or ''
            if d:
                d = ', %d duplicate' % self._duplicate
            self._printf('%*d object%s given%s', w, n, _plural(n), d, **print3opts)
        t = sum(1 for t in _values(self._seen) if t != 0)
        self._printf('%*d object%s sized', w, t, _plural(t), **print3opts)
        if self._excl_d:
            t = sum(_values(self._excl_d))
            self._printf('%*d object%s excluded', w, t, _plural(t), **print3opts)
        t = sum(_values(self._seen))
        self._printf('%*d object%s seen', w, t, _plural(t), **print3opts)
        if self._missed > 0:
            self._printf('%*d object%s missed', w, self._missed, _plural(self._missed), **print3opts)
        if self._depth > 0:
            self._printf('%*d recursion depth', w, self._depth, **print3opts)

    def print_typedefs(self, w=0, **print3opts):
        '''Print the types and dict tables.

               *w=0*            -- indentation for each line

               *print3options*  -- print options, as in Python 3.0
        '''
        for k in _all_kinds:
             # XXX Python 3.0 doesn't sort type objects
            t = [(self._prepr(a), v) for a, v in _items(_typedefs) if v.kind == k and (v.both or self._code_)]
            if t:
                self._printf('%s%*d %s type%s:  basicsize, itemsize, _len_(), _refs()',
                             linesep, w, len(t), k, _plural(len(t)), **print3opts)
                for a, v in sorted(t):
                    self._printf('%*s %s:  %s', w, '', a, v, **print3opts)
         # dict and dict-like classes
        t = sum(len(v) for v in _values(_dict_classes))
        if t:
            self._printf('%s%*d dict/-like classes:', linesep, w, t, **print3opts)
            for m, v in _items(_dict_classes):
                self._printf('%*s %s:  %s', w, '', m, self._prepr(v), **print3opts)

    def set(self, align=None, code=None, detail=None, limit=None, stats=None):
        '''Set some options.  See also **reset**.

               *align*   -- size alignment

               *code*    -- incl. (byte)code size

               *detail*  -- Asized refs level

               *limit*   -- recursion limit

               *stats*   -- print statistics, see function **asizeof**

        Any options not set remain unchanged from the previous setting.
        '''
         # adjust
        if align is not None:
            self._align_ = align
            if align > 1:
                self._mask = align - 1
                if (self._mask & align) != 0:
                    raise ValueError('invalid option: %s=%r' % ('align', align))
            else:
                self._mask = 0
        if code is not None:
            self._code_ = code
            if code:  # incl. (byte)code
                self._incl = ' (incl. code)'
        if detail is not None:
            self._detail_ = detail
        if limit is not None:
            self._limit_ = limit
        if stats is not None:
            self._stats_ = s = int(stats)
            self._cutoff = (stats - s) * 100
            if s > 1:  # profile types
                self._profile = True
            else:
                self._profile = False

    def _get_duplicate(self):
        '''Number of duplicate objects.
        '''
        return self._duplicate
    duplicate = property(_get_duplicate, doc=_get_duplicate.__doc__)

    def _get_missed(self):
        '''Number of objects missed due to errors.
        '''
        return self._missed
    missed = property(_get_missed, doc=_get_missed.__doc__)

    def _get_total(self):
        '''Total size accumulated so far.
        '''
        return self._total
    total = property(_get_total, doc=_get_total.__doc__)

    def reset(self, align=8, clip=80, code=False, derive=False,
              detail=0, ignored=True, infer=False, limit=100, stats=0,
              stream=None):
        '''Reset options, state, etc.

        The available options and default values are:

             *align=8*       -- size alignment

             *clip=80*       -- clip repr() strings

             *code=False*    -- incl. (byte)code size

             *derive=False*  -- derive from super type

             *detail=0*      -- Asized refs level

             *ignored=True*  -- ignore certain types

             *infer=False*   -- try to infer types

             *limit=100*     -- recursion limit

             *stats=0.0*     -- print statistics, see function **asizeof**

             *stream=None*   -- output stream for printing

        See function **asizeof** for a description of the options.
        '''
         # options
        self._align_ = align
        self._clip_ = clip
        self._code_ = code
        self._derive_ = derive
        self._detail_ = detail  # for Asized only
        self._infer_ = infer
        self._limit_ = limit
        self._stats_ = stats
        self._stream = stream
        if ignored:
            self._ign_d = _kind_ignored
        else:
            self._ign_d = None
         # clear state
        self._clear()
        self.set(align=align, code=code, stats=stats)


 # public functions

def adict(*classes):
    '''Install one or more classes to be handled as dict.
    '''
    a = True
    for c in classes:
         # if class is dict-like, add class
         # name to _dict_classes[module]
        if isclass(c) and _infer_dict(c):
            t = _dict_classes.get(c.__module__, ())
            if c.__name__ not in t:  # extend tuple
                _dict_classes[c.__module__] = t + (c.__name__,)
        else:  # not a dict-like class
            a = False
    return a  # all installed if True


_asizer = Asizer()


def asized(*objs, **opts):
    '''Return a tuple containing an **Asized** instance for each
       object passed as positional argment using the following
       options.

           *align=8*       -- size alignment

           *clip=80*       -- clip repr() strings

           *code=False*    -- incl. (byte)code size

           *derive=False*  -- derive from super type

           *detail=0*      -- Asized refs level

           *ignored=True*  -- ignore certain types

           *infer=False*   -- try to infer types

           *limit=100*     -- recursion limit

           *stats=0.0*     -- print statistics

       If only one object is given, the return value is the **Asized**
       instance for that object.  Otherwise, the length of the returned
       tuple matches the number of given objects.

       Set *detail* to the desired referents level (recursion depth).

       See function **asizeof** for descriptions of the other options.

    '''
    if 'all' in opts:
        raise KeyError('invalid option: %s=%r' % ('all', opts['all']))
    if objs:
        _asizer.reset(**opts)
        t = _asizer.asized(*objs)
        _asizer.print_stats(objs, opts=opts, sized=t)  # show opts as _kwdstr
        _asizer._clear()
    else:
        t = ()
    return t


def asizeof(*objs, **opts):
    '''Return the combined size in bytes of all objects passed as positional arguments.

    The available options and defaults are the following.

         *align=8*       -- size alignment

         *all=False*     -- all current objects

         *clip=80*       -- clip ``repr()`` strings

         *code=False*    -- incl. (byte)code size

         *derive=False*  -- derive from super type

         *ignored=True*  -- ignore certain types

         *infer=False*   -- try to infer types

         *limit=100*     -- recursion limit

         *stats=0.0*     -- print statistics

    Set *align* to a power of 2 to align sizes.  Any value less
    than 2 avoids size alignment.

    All current module, global and stack objects are sized if
    *all* is True and if no positional arguments are supplied.

    A positive *clip* value truncates all repr() strings to at
    most *clip* characters.

    The (byte)code size of callable objects like functions,
    methods, classes, etc. is included only if *code* is True.

    If *derive* is True, new types are handled like an existing
    (super) type provided there is one and only of those.

    By default certain base types like object, super, etc. are
    ignored.  Set *ignored* to False to include those.

    If *infer* is True, new types are inferred from attributes
    (only implemented for dict types on callable attributes
    as get, has_key, items, keys and values).

    Set *limit* to a positive value to accumulate the sizes of
    the referents of each object, recursively up to the limit.
    Using *limit=0* returns the sum of the flat[4] sizes of
    the given objects.  High *limit* values may cause runtime
    errors and miss objects for sizing.

    A positive value for *stats* prints up to 8 statistics, (1)
    a summary of the number of objects sized and seen, (2) a
    simple profile of the sized objects by type and (3+) up to
    6 tables showing the static, dynamic, derived, ignored,
    inferred and dict types used, found resp. installed.  The
    fractional part of the *stats* value (x100) is the cutoff
    percentage for simple profiles.

    [4] See the documentation of this module for the definition of flat size.
    '''
    t, p = _objs_opts(objs, **opts)
    if t:
        _asizer.reset(**p)
        s = _asizer.asizeof(*t)
        _asizer.print_stats(objs=t, opts=opts)  # show opts as _kwdstr
        _asizer._clear()
    else:
        s = 0
    return s


def asizesof(*objs, **opts):
    '''Return a tuple containing the size in bytes of all objects
       passed as positional argments using the following options.

           *align=8*       -- size alignment

           *clip=80*       -- clip ``repr()`` strings

           *code=False*    -- incl. (byte)code size

           *derive=False*  -- derive from super type

           *ignored=True*  -- ignore certain types

           *infer=False*   -- try to infer types

           *limit=100*     -- recursion limit

           *stats=0.0*     -- print statistics

       See function **asizeof** for a description of the options.

       The length of the returned tuple equals the number of given
       objects.
    '''
    if 'all' in opts:
        raise KeyError('invalid option: %s=%r' % ('all', opts['all']))
    if objs:  # size given objects
        _asizer.reset(**opts)
        t = _asizer.asizesof(*objs)
        _asizer.print_stats(objs, opts=opts, sizes=t)  # show opts as _kwdstr
        _asizer._clear()
    else:
        t = ()
    return t


def _typedefof(obj, save=False, **opts):
    '''Get the typedef for an object.
    '''
    k = _objkey(obj)
    v = _typedefs.get(k, None)
    if not v:  # new typedef
        v = _typedef(obj, **opts)
        if save:
            _typedefs[k] = v
    return v


def basicsize(obj, **opts):
    '''Return the basic size of an object (in bytes).

       Valid options and defaults are

           *derive=False*  -- derive type from super type

           *infer=False*   -- try to infer types

           *save=False*    -- save typedef if new
    '''
    v = _typedefof(obj, **opts)
    if v:
        v = v.base
    return v


def flatsize(obj, align=0, **opts):
    '''Return the flat size of an object (in bytes),
       optionally aligned to a given power of 2.

       See function **basicsize** for a description of
       the other options.  See the documentation of
       this module for the definition of flat size.
    '''
    v = _typedefof(obj, **opts)
    if v:
        if align > 1:
            m = align - 1
            if (align & m) != 0:
                raise ValueError('invalid option: %s=%r' % ('align', align))
        else:
            m = 0
        v = v.flat(obj, m)
    return v


def itemsize(obj, **opts):
    '''Return the item size of an object (in bytes).

       See function **basicsize** for a description of
       the options.
    '''
    v = _typedefof(obj, **opts)
    if v:
        v = v.item
    return v


def leng(obj, **opts):
    '''Return the length of an object (in items).

       See function **basicsize** for a description of
       the options.
    '''
    v = _typedefof(obj, **opts)
    if v:
        v = v.leng
        if v and _callable(v):
            v = v(obj)
    return v


def refs(obj, **opts):
    '''Return (a generator for) specific referents of an
       object.

       See function **basicsize** for a description of
       the options.
    '''
    v = _typedefof(obj, **opts)
    if v:
        v = v.refs
        if v and _callable(v):
            v = v(obj, False)
    return v


def named_refs(obj):
    """
    Return all named referents of `obj`. Reuse functionality from asizeof.
    Does not return referents without a name, e.g. objects in a list.
    """
    refs = []
    v = _typedefof(obj)
    if v:
        v = v.refs
        if v and _callable(v):
            for ref in v(obj, True):
                try:
                    refs.append((ref.name, ref.ref))
                except AttributeError:
                    pass
    return refs


# License file from an earlier version of this source file follows:

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#       Copyright (c) 2002-2008 -- ProphICy Semiconductor, Inc.
#                        All rights reserved.
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# modification, are permitted provided that the following conditions
# are met:
#
# - Redistributions of source code must retain the above copyright
#   notice, this list of conditions and the following disclaimer.
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# - Redistributions in binary form must reproduce the above copyright
#   notice, this list of conditions and the following disclaimer in
#   the documentation and/or other materials provided with the
#   distribution.
#
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#   of its contributors may be used to endorse or promote products
#   derived from this software without specific prior written
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#
# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
# FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE
# COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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# HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
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# ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
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#---------------------------------------------------------------------
