import sys
import resource


# on my settings, these settings cause segmentation fault in ~30 seconds.
# note that I set SCALE_EXPRESSION_BY to 10,000 as well
resource.setrlimit(resource.RLIMIT_DATA, (92233720368, 92233720368))
resource.setrlimit(resource.RLIMIT_STACK, (8372, 67090))


# multiply the large expression in the 'nastiness' string by this factor
# floating point numbers are supported
SCALE_EXPRESSION_BY = 10000

class ExecMethods:
    COMPILE_ONLY = 0
    COMPILE_THEN_EXEC = 1
    ONE_STEP_EXEC = 2

USE_EXECMETHOD = ExecMethods.COMPILE_THEN_EXEC

# --- do not change. ---
# when this magic number is 50 and the constant above is 1, you get the
# original example posted by @mjo
SCALING_CONSTANT = 88
# ------ 


def do_compile():
    """Return a booean indicating success"""
    try:
        if USE_EXECMETHOD == ExecMethods.COMPILE_ONLY:
            compile(nastiness, '', 'exec')
        elif USE_EXECMETHOD == ExecMethods.COMPILE_THEN_EXEC:
            co = compile(nastiness, '', 'exec')
            exec(co)
        elif USE_EXECMETHOD == ExecMethods.ONE_STEP_EXEC:
            exec(nastiness)
        return True
    except RecursionError:
        return False


def grow_to_success():
    """At the bottom, this runs for python3"""
    limit = sys.getrecursionlimit()
    while not do_compile():
        print('limit: {}'.format(limit))
        limit = int(limit * 1.3)
        sys.setrecursionlimit(limit)
    return limit


def shrink_to_failure():
    """At the bottom, this runs for python2"""
    limit = sys.getrecursionlimit()
    while do_compile():
        print('limit: {}'.format(limit))
        limit = int(limit * 0.5)
        sys.setrecursionlimit(limit)
    return limit


nastiness = ("""d2u1 = 1
d2u1u2 = 2
d2u1u3 = 3
d2u2 = 5
d2u2u3 = 7
d2u3 = 11
du1 = 13
du2 = 17
du3 = 19
u1 = 23
u2 = 29
u3 = 31

DPT = """

+ ("""1/2*(u1^12*u2^5*d2u1 + 6*u1^11*u2^6*d2u1 + 16*u1^10*u2^7*d2u1 + """
+ ("""25*u1^9*u2^8*d2u1 + 25*u1^8*u2^9*d2u1 + 16*u1^7*u2^10*d2u1 + 6*u1^6*u2^11*d2u1 + 
u1^5*u2^12*d2u1 + 5*u1^12*u2^4*u3*d2u1 + 36*u1^11*u2^5*u3*d2u1 + 
116*u1^10*u2^6*u3*d2u1 + 220*u1^9*u2^7*u3*d2u1 + 270*u1^8*u2^8*u3*d2u1 + 
220*u1^7*u2^9*u3*d2u1 + 116*u1^6*u2^10*u3*d2u1 + 36*u1^5*u2^11*u3*d2u1 + 
5*u1^4*u2^12*u3*d2u1 + 10*u1^12*u2^3*u3^2*d2u1 + 90*u1^11*u2^4*u3^2*d2u1 + 
"""
* int(SCALE_EXPRESSION_BY * SCALING_CONSTANT))
+ """356*u1^10*u2^5*u3^2*d2u1)"""))


if __name__ == '__main__':
    if sys.version_info[0] == 3:
        grow_to_success()
    else:
        shrink_to_failure()