Proposed Python hashdos fix

gistfile1.py

#copied from pypy to make it convenient to run the code
def intmask(n):
    if isinstance(n, int):
        return int(n)   # possibly bool->int
    assert not isinstance(n, float)
    n = long(n)
    n &= 18446744073709551615
    if n >= 9223372036854775808:
        n -= 2*9223372036854775808
    return int(n)

#Original PyPY version
#--------------------------------------
def _hash_string(s):
    """The algorithm behind compute_hash() for a string or a unicode."""
    length = len(s)
    if length == 0:
        return -1
    x = ord(s[0]) << 7
    i = 0
    while i < length:
        x = intmask((1000003*x) ^ ord(s[i]))
        i += 1
    x ^= length
    return intmask(x)

#Proposed replacement
#--------------------------------------
import os, array
size_exponent = 14 #adjust as a memory/security tradeoff
r = array.array('l', os.urandom(2**size_exponent))
len_r = len(r)

def _hash_string2(s):
    """The algorithm behind compute_hash() for a string or a unicode."""
    length = len(s)
    #print s
    if length == 0:
        return -1
    x = (ord(s[0]) << 7) ^ r[length % len_r]
    i = 0
    while i < length:
        x = intmask((1000003*x) ^ ord(s[i]))
        x ^= r[x % len_r]
        i += 1
    x ^= length
    return intmask(x)