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
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?)
Added $(SYSDEF) to its build rule in Makefile.
* cgensupport.[ch], modsupport.[ch]: removed some old stuff. Also
changed files that still used it... And made several things static
that weren't but should have been... And other minor cleanups...
* listobject.[ch]: add external interfaces {set,get}listslice
* socketmodule.c: fix bugs in new send() argument parsing.
* sunaudiodevmodule.c: added flush() and close().
* Stubs for faster implementation of local variables (not yet finished)
* Added function name to code object. Print it for code and function
objects. THIS MAKES THE .PYC FILE FORMAT INCOMPATIBLE (the version
number has changed accordingly)
* Print address of self for built-in methods
* New internal functions getattro and setattro (getattr/setattr with
string object arg)
* Replaced "dictobject" with more powerful "mappingobject"
* New per-type functio tp_hash to implement arbitrary object hashing,
and hashobject() to interface to it
* Added built-in functions hash(v) and hasattr(v, 'name')
* classobject: made some functions static that accidentally weren't;
added __hash__ special instance method to implement hash()
* Added proper comparison for built-in methods and functions
* Fixcprt.py: added [-y file] option, do only files younger than file.
* modsupport.[ch]: added vmkvalue().
* intobject.c: use mkvalue().
* stringobject.c: added "formatstring"; renamed string* to string_*;
ceval.c: call formatstring for string % value.
* longobject.c: close memory leak in divmod.
* parsetok.c: set result node to NULL when returning an error.
* various modules: added 1993 to copyright.
* thread.c: added copyright notice.
* ceval.c: minor change to error message for "+"
* stdwinmodule.c: check for error from wfetchcolor
* config.c: MS-DOS fixes (define PYTHONPATH, use DELIM, use osdefs.h)
* Add declaration of inittab to import.h
* sysmodule.c: added sys.builtin_module_names
* xxmodule.c, xxobject.c: fix minor errors
stdwinmodule.c: wsetfont can now return an error
Makefile: add CL_USE and CL_LIB*S; config.c: move CL part around
New things in imgfile; also in Makefile.
longobject.c: fix comparison of negative long ints... [REAL BUG!]
marshal.c: add dumps() and loads() to read/write strings
timemodule.c: make sure there's always a floatsleep()
posixmodule.c: rationalize struct returned by times()
Makefile: add test target, disable imgfile by default
thread.c: Improved coexistance with dl module (sjoerd)
stdwinmodule.c: Change include stdwin.h if macintosh
rotormodule.c: added missing last argument to RTR_?_region calls
confic.c: merged with configmac.c, added 1993 to copyright message
fileobject.c: int compared to NULL in writestring(); change fopenRF ifdef
timemodule.c: simplify times() using mkvalue; include myselect.h
earlier (for sequent).
posixmodule: for sequent, include unistd.h instead of explicit
extern definitions and don't define rename()
Makefile: change misleading/wrong MD5 comments
* flmodule.c: added some missing functions; changed readonly flags of
some data members based upon FORMS documentation.
* listobject.c: fixed int/long arg lint bug (bites PC compilers).
* several: removed redundant print methods (repr is good enough).
* posixmodule.c: added (still experimental) process group functions.
coercion is now completely generic.
* ceval.c: for instances, don't coerce for + and *; * reverses
arguments if left one is non-instance numeric and right one sequence.
Guido van Rossum