--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/symbian-qemu-0.9.1-12/python-2.6.1/Misc/find_recursionlimit.py Fri Jul 31 15:01:17 2009 +0100
@@ -0,0 +1,117 @@
+#! /usr/bin/env python
+"""Find the maximum recursion limit that prevents interpreter termination.
+
+This script finds the maximum safe recursion limit on a particular
+platform. If you need to change the recursion limit on your system,
+this script will tell you a safe upper bound. To use the new limit,
+call sys.setrecursionlimit().
+
+This module implements several ways to create infinite recursion in
+Python. Different implementations end up pushing different numbers of
+C stack frames, depending on how many calls through Python's abstract
+C API occur.
+
+After each round of tests, it prints a message:
+"Limit of NNNN is fine".
+
+The highest printed value of "NNNN" is therefore the highest potentially
+safe limit for your system (which depends on the OS, architecture, but also
+the compilation flags). Please note that it is practically impossible to
+test all possible recursion paths in the interpreter, so the results of
+this test should not be trusted blindly -- although they give a good hint
+of which values are reasonable.
+
+NOTE: When the C stack space allocated by your system is exceeded due
+to excessive recursion, exact behaviour depends on the platform, although
+the interpreter will always fail in a likely brutal way: either a
+segmentation fault, a MemoryError, or just a silent abort.
+
+NB: A program that does not use __methods__ can set a higher limit.
+"""
+
+import sys
+import itertools
+
+class RecursiveBlowup1:
+ def __init__(self):
+ self.__init__()
+
+def test_init():
+ return RecursiveBlowup1()
+
+class RecursiveBlowup2:
+ def __repr__(self):
+ return repr(self)
+
+def test_repr():
+ return repr(RecursiveBlowup2())
+
+class RecursiveBlowup4:
+ def __add__(self, x):
+ return x + self
+
+def test_add():
+ return RecursiveBlowup4() + RecursiveBlowup4()
+
+class RecursiveBlowup5:
+ def __getattr__(self, attr):
+ return getattr(self, attr)
+
+def test_getattr():
+ return RecursiveBlowup5().attr
+
+class RecursiveBlowup6:
+ def __getitem__(self, item):
+ return self[item - 2] + self[item - 1]
+
+def test_getitem():
+ return RecursiveBlowup6()[5]
+
+def test_recurse():
+ return test_recurse()
+
+def test_cpickle(_cache={}):
+ try:
+ import cPickle
+ except ImportError:
+ print "cannot import cPickle, skipped!"
+ return
+ l = None
+ for n in itertools.count():
+ try:
+ l = _cache[n]
+ continue # Already tried and it works, let's save some time
+ except KeyError:
+ for i in range(100):
+ l = [l]
+ cPickle.dumps(l, protocol=-1)
+ _cache[n] = l
+
+def check_limit(n, test_func_name):
+ sys.setrecursionlimit(n)
+ if test_func_name.startswith("test_"):
+ print test_func_name[5:]
+ else:
+ print test_func_name
+ test_func = globals()[test_func_name]
+ try:
+ test_func()
+ # AttributeError can be raised because of the way e.g. PyDict_GetItem()
+ # silences all exceptions and returns NULL, which is usually interpreted
+ # as "missing attribute".
+ except (RuntimeError, AttributeError):
+ pass
+ else:
+ print "Yikes!"
+
+limit = 1000
+while 1:
+ check_limit(limit, "test_recurse")
+ check_limit(limit, "test_add")
+ check_limit(limit, "test_repr")
+ check_limit(limit, "test_init")
+ check_limit(limit, "test_getattr")
+ check_limit(limit, "test_getitem")
+ check_limit(limit, "test_cpickle")
+ print "Limit of %d is fine" % limit
+ limit = limit + 100