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#
# 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
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