mirror of https://github.com/python/cpython
43 lines
1.0 KiB
Python
43 lines
1.0 KiB
Python
#
|
|
# These tests require gmpy and test the limits of the 32-bit build. The
|
|
# limits of the 64-bit build are so large that they cannot be tested
|
|
# on accessible hardware.
|
|
#
|
|
|
|
import sys
|
|
from decimal import *
|
|
from gmpy import mpz
|
|
|
|
|
|
_PyHASH_MODULUS = sys.hash_info.modulus
|
|
# hash values to use for positive and negative infinities, and nans
|
|
_PyHASH_INF = sys.hash_info.inf
|
|
_PyHASH_NAN = sys.hash_info.nan
|
|
|
|
# _PyHASH_10INV is the inverse of 10 modulo the prime _PyHASH_MODULUS
|
|
_PyHASH_10INV = pow(10, _PyHASH_MODULUS - 2, _PyHASH_MODULUS)
|
|
|
|
def xhash(coeff, exp):
|
|
sign = 1
|
|
if coeff < 0:
|
|
sign = -1
|
|
coeff = -coeff
|
|
if exp >= 0:
|
|
exp_hash = pow(10, exp, _PyHASH_MODULUS)
|
|
else:
|
|
exp_hash = pow(_PyHASH_10INV, -exp, _PyHASH_MODULUS)
|
|
hash_ = coeff * exp_hash % _PyHASH_MODULUS
|
|
ans = hash_ if sign == 1 else -hash_
|
|
return -2 if ans == -1 else ans
|
|
|
|
|
|
x = mpz(10) ** 425000000 - 1
|
|
coeff = int(x)
|
|
|
|
d = Decimal('9' * 425000000 + 'e-849999999')
|
|
|
|
h1 = xhash(coeff, -849999999)
|
|
h2 = hash(d)
|
|
|
|
assert h2 == h1
|