From: "Tim Peters" <tim_one@email.msn.com>
To: "Guido van Rossum" <guido@CNRI.Reston.VA.US>
Date: Sat, 23 May 1998 21:45:53 -0400
Guido, the overflow checking in PyLong_AsLong is off a little:
1) If the C in use sign-extends right shifts on signed longs, there's a
spurious overflow error when converting the most-negative int:
Python 1.5.1 (#0, Apr 13 1998, 20:22:04) [MSC 32 bit (Intel)] on win32
Copyright 1991-1995 Stichting Mathematisch Centrum, Amsterdam
>>> x = -1L << 31
>>> x
-2147483648L
>>> int(x)
Traceback (innermost last):
File "<stdin>", line 1, in ?
OverflowError: long int too long to convert
>>>
2) If C does not sign-extend, some genuine overflows won't be caught.
The attached should repair both, and, because I installed a new disk and a C
compiler today, it's even been compiled this time <wink>.
Python 1.5.1 (#0, May 23 1998, 20:24:58) [MSC 32 bit (Intel)] on win32
Copyright 1991-1995 Stichting Mathematisch Centrum, Amsterdam
>>> x = -1L << 31
>>> x
-2147483648L
>>> int(x)
-2147483648
>>> int(-x)
Traceback (innermost last):
File "<stdin>", line 1, in ?
OverflowError: long int too long to convert
>>> int(-x-1)
2147483647
>>> int(x-1)
Traceback (innermost last):
File "<stdin>", line 1, in ?
OverflowError: long int too long to convert
>>>
end-casing-ly y'rs - tim
Make sure that no tp_as_numbers->nb_<whatever> function is called
without checking for a NULL pointer. Marc-Andre Lemburg will love it!
(Except that he's just rewritten all this code for a different
approach to coercions ;-( )
programming style.
Recoded many routines to incorporate better error checking, and/or
better versions of the same function found elsewhere
(e.g. bltinmodule.c or ceval.c). In particular,
Py_Number_{Int,Long,Float}() now convert from strings, just like the
built-in functions int(), long() and float().
Sequences and mappings are now safe to have NULL function pointers
anywhere in their tp_as_sequence or tp_as_mapping fields. (A few
places in other files need to be checked in too.)
Renamed PySequence_In() to PySequence_Contains().
clear_carefully() used to do in import.c. Differences: leave only
__builtins__ alone in the 2nd pass; and don't clear the dictionary (on
the theory that as long as there are references left to the
dictionary, those might be destructors that might expect __builtins__
to be alive when they run; and __builtins__ can't normally be part of
a cycle).
PyNumber_Coerce() except that when the coercion can't be done and no
other exceptions happen, it returns 1 instead of raising an
exception.
Use this function in PyObject_Compare() to avoid raising an exception
simply because two objects with numeric behavior can't be coerced to a
common type; instead, proceed with the non-numeric default comparison.
Note that this is a somewhat questionable practice -- comparisons for
numeric objects shouldn't default to random behavior like this, but it
is required for backward compatibility. (Case in point, it broke
comparison of kjDict objects to integers in Aaron Watters' kjbuckets
extension.) A correct fix (for python 2.0) should involve a different
definiton of comparison altogether.
sys.stdin.readline(), you get a fatal error (no current thread). This
is because there was a call to PyErr_CheckSignals() while there was no
current thread. I wonder how many more of these we find... I bnetter
go hunting for PyErr_CheckSignals() now...
in libmath.a so they are available to mathmodule.so (in case it is
shared). While this still gets triggered on Solaris 2.x, this appears
to be harmless there.
__getitem__(). This method never raises an exception; if the key is
not in the dictionary, the second (optional) argument is returned. If
the second argument is not provided and the key is missing, None is
returned.
mapp_methods: added "get" method.
arbitrary nested parens in a %(...)X style format.
#Also folded two lines and added more detail to the error message for
#unsupported format character.
former lets you give an instance a set of new instance vars. The
latter lets you give it a new class. Both are typechecked and
disallowed in restricted mode.
For classes, the check for read-only special attributes is tightened
so that only assignments to __dict__, __bases__, __name__,
__getattr__, __setattr__, and __delattr__ (these could be made to work
as well, but I don't know if that's useful -- let's see first whether
mucking with instances will help).
from the interned table. There are references in hard-to-find static
variables all over the interpreter, and it's not worth trying to get
rid of all those; but "uninterning" isn't fair either and may cause
subtle failures later -- so we have to keep them in the interned
table.
Also get rid of no-longer-needed insert of None in interned dict.
no valid directory is passed in. This prevents __del__ to fail when
invoked after __builtins__ has already been discarded.
Also add PyFrame_Fini() to discard the cache of frames.
In _Py_PrintReferences(), no longer suppress once-referenced string.
Add Py_Malloc and friends and PyMem_Malloc and friends (malloc
wrappers for third parties).
complexity saved much any more. A simple benchmark (grail) showed
that there were 3 times as many misses as hits, and the same number of
times again the code was bypassed altogether due to the existence of
setattro/getattro.
this many bytes have been read, readlines stops. Because of
buffering, the amount of bytes read is usually at least 8K more than
the hint.
Also changed read() and readline() to use PyArg_ParseTuple().
(Note that the *previous* checkin also fixed error handling and
narrowed the range of thread unblocking for all methods using
fread().)
see if we can guess the #bytes until the end of the file. If we
can't, increment the buffer size increments up to 0.5Meg to avoid
realloc'ing too much.
The table size is now constrained to be a power of two, and we use a
variable increment based on GF(2^n)-{0} (not that I have the faintest
idea what that is :-) which helps avoid the expensive '%' operation.
Some of the entries in the table of polynomials have been modified
according to a post by Tim Peters.
Rather than allocating a list object for the fast locals and another
(extensible one) for the value stack and allocating the block stack
dynamically, allocate the block stack with a fixed size (CO_MAXBLOCKS
from compile.h), and stick the locals and value stack at the end of
the object (this is now possible since the stack size is known
beforehand). Get rid of the owner field and the nvalues argument --
it is available in the code object, like nlocals.
This requires small changes in ceval.c only.
sequence, otherwise
operator.indexOf([4, 3, 2, 1], 9) would raise a SystemError!
Note: it might be wise to double check all these functions. I haven't
done that yet.
object pointers. Should be a bit faster than the C library's qsort(),
and doesn't have the prohibition on recursion that Solaris qsort() has
in the threaded version of their C library.
Thanks to discussions with Tim Peters.
defines that a shorter dictionary is always smaller than a longer one.
For dictionaries of the same size, the smallest differing element
determines the outcome (which yields the same results as before,
without explicit sorting).
be Ellipsis!).
Bumped the API version because a linker-visible symbol is affected.
Old C code will still compile -- there's a b/w compat macro.
Similarly, old Python code will still run, builtin exports both
Ellipses and Ellipsis.
Removed im_doc attribute; __name__ and __doc__ are now handled by
special casing in instancemethodgetattr(). This saves a few bytes and
INCREF/DECREF calls per i.m. object allocation/deallocation.
getcounts() returns a list of counts of allocations and
deallocations for all different object types.
getobjects(n [, type ]) returns a list of recently allocated
and not-yet-freed objects of the given type (all
objects if no type given). Only the n most recent
(all if n==0) objects are returned.
getcounts is only available if compiled with -DCOUNT_ALLOCS,
getobjects is only available if compiled with -DTRACE_REFS. Note that
everything must be compiled with these options!
entirely redone operator overloading. The rules for class
instances are now much more relaxed than for other built-in types
(whose coerce must still return two objects of the same type)
* Objects/floatobject.c: add overflow check when converting float
to int and implement truncation towards zero using ceil/float
* Objects/longobject.c: change ValueError to OverflowError when
converting to int
* Objects/rangeobject.c: modernized
* Objects/stringobject.c: use HAVE_LIMITS instead of __STDC__
* Objects/xxobject.c: changed to use new style (not finished?)
and __setattr__ support to override getattr(x, name) and
setattr(x, name, value) for class instances. This uses a special
hack whereby the class is supposed to be static: the __getattr__
and __setattr__ methods are looked up only once and saved in the
instance structure for speed
* funcobject.c (func_repr): don't call getstringvalue(None) for anonymous
functions.
* bltinmodule.c: removed lambda (which is now a built-in function);
removed implied lambda for string arg to filter/map/reduce.
* Grammar, graminit.[ch], compile.[ch]: replaced lambda as built-in
function by lambda as grammar entity: instead of "lambda('x: x+1')" you
write "lambda x: x+1".
* Xtmodule.c (checkargdict): return 0, not NULL, for error.
* posixmodule.c: don't prototype getcwd() -- it's not portable...
* mappingobject.c: double-check validity of last_name_char in
dict{lookup,insert,remove}.
* arraymodule.c: need memmove only for non-STDC Suns.
* Makefile: comment out HTML_LIBS and XT_USE by default
* pythonmain.c: don't prototype getopt() -- it's not standardized
* socketmodule.c: cast flags arg to {get,set}sockopt() and addrbuf arg to
recvfrom() to (ANY*).
* pythonrun.c (initsigs): fix prototype, make it static
* intobject.c (LONG_BIT): only #define it if not already defined
* classobject.[ch]: remove all references to unused instance_convert()
* mappingobject.c (getmappingsize): Don't return NULL in int function.
each dir in sys.path, try each possible extension. (Note: C extensions
are loaded before Python modules in the same directory, to allow having
a C version used when dynamic loading is supported and a Python version
as a back-up.)
* import.c (reload_module): test for error from getmodulename()
* moduleobject.c: implement module name as dict entry '__name__' instead
of special-casing it in module_getattr(); this way a module (or
function!) can access its own module name, and programs that know what
they are doing can rename modules.
* stdwinmodule.c (initstdwin): strip ".py" suffix of argv[0].
* {tuple,list,mapping,array}object.c: call printobject with 0 for flags
* compile.c (parsestr): use quote instead of '\'' at one crucial point
* arraymodule.c (array_getattr): Added __members__ attribute
* object.[ch], bltinmodule.c, fileobject.c: changed str() to call
strobject() which calls an object's __str__ method if it has one.
strobject() is also called by writeobject() when PRINT_RAW is passed.
* ceval.c: rationalize code for PRINT_ITEM (no change in function!)
* funcobject.c, codeobject.c: added compare and hash functionality.
Functions with identical code objects and the same global dictionary are
equal. Code objects are equal when their code, constants list and names
list are identical (i.e. the filename and code name don't count).
(hash doesn't work yet since the constants are in a list and lists can't
be hashed -- suppose this should really be done with a tuple now we have
resizetuple!)
setlistslice() can be used to cut the unused part out of a freshly made
slice (as done by bagof()). [needed by the next mod!]
* structural changes to bagof(), map() etc.
* PROTO.h, mymalloc.h: added #ifdefs for TURBOC and GNUC.
* allobjects.h: added #include "rangeobject.h"
* Grammar: added lambda_input; relaxed syntax for exec.
* bltinmodule.c: added bagof, map, reduce, lambda, xrange.
* tupleobject.[ch]: added resizetuple().
* rangeobject.[ch]: new object type to speed up range operations (not
convinced this is needed!!!)
* Grammar: add exec statement; allow testlist in expr statement.
* ceval.c, compile.c, opcode.h: support exec statement;
avoid optimizing locals when it is used
* fileobject.{c,h}: add getfilename() internal function.
shared. The default is to save references to the integers in
the range -1..99. The lower limit can be set by defining
NSMALLNEGINTS (absolute value of smallest integer to be saved)
and NSMALLPOSINTS (1 more than the largest integer to be
saved).
tupleobject.c: Save a reference to the empty tuple to be returned
whenever a tuple of size 0 is requested. Tuples of size 1
upto, but not including, MAXSAVESIZE (default 20) are put in
free lists when deallocated. When MAXSAVESIZE equals 1, only
share references to the empty tuple, when MAXSAVESIZE equals
0, don't include the code at all and revert to the old
behavior.
object.c: Print some more statistics when COUNT_ALLOCS is defined.
without .py file); Bill's dynamic loading for SunOS using shared
libraries.
pwdmodule.c (mkgrent): remove DECREF of uninitialized variable.
classobject.c (instance_getattr): Fix case when class lookup returns
unbound method instead of function.
image objects, and lots of new methods.
* Added counting of allocations and deallocations of builtin types if
COUNT_ALLOCS is defined. Had to move calls to NEWREF down in some
files.
* Bug fix in sorting lists.
Guido van Rossum
Barry Warsaw
Jack Jansen
Sjoerd Mullender