mirror of https://github.com/python/cpython
80 lines
2.7 KiB
Python
80 lines
2.7 KiB
Python
import sys
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import unittest
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from test.support import import_helper
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_testcapi = import_helper.import_module('_testcapi')
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SIZEOF_VOID_P = _testcapi.SIZEOF_VOID_P
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SIZEOF_PY_HASH_T = SIZEOF_VOID_P
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class CAPITest(unittest.TestCase):
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def test_hash_getfuncdef(self):
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# Test PyHash_GetFuncDef()
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hash_getfuncdef = _testcapi.hash_getfuncdef
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func_def = hash_getfuncdef()
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match func_def.name:
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case "fnv":
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self.assertEqual(func_def.hash_bits, 8 * SIZEOF_PY_HASH_T)
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self.assertEqual(func_def.seed_bits, 16 * SIZEOF_PY_HASH_T)
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case "siphash13":
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self.assertEqual(func_def.hash_bits, 64)
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self.assertEqual(func_def.seed_bits, 128)
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case "siphash24":
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self.assertEqual(func_def.hash_bits, 64)
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self.assertEqual(func_def.seed_bits, 128)
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case _:
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self.fail(f"unknown function name: {func_def.name!r}")
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# compare with sys.hash_info
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hash_info = sys.hash_info
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self.assertEqual(func_def.name, hash_info.algorithm)
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self.assertEqual(func_def.hash_bits, hash_info.hash_bits)
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self.assertEqual(func_def.seed_bits, hash_info.seed_bits)
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def test_hash_pointer(self):
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# Test Py_HashPointer()
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hash_pointer = _testcapi.hash_pointer
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UHASH_T_MASK = ((2 ** (8 * SIZEOF_PY_HASH_T)) - 1)
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HASH_T_MAX = (2 ** (8 * SIZEOF_PY_HASH_T - 1) - 1)
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def python_hash_pointer(x):
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# Py_HashPointer() rotates the pointer bits by 4 bits to the right
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x = (x >> 4) | ((x & 15) << (8 * SIZEOF_VOID_P - 4))
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# Convert unsigned uintptr_t (Py_uhash_t) to signed Py_hash_t
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if HASH_T_MAX < x:
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x = (~x) + 1
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x &= UHASH_T_MASK
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x = (~x) + 1
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return x
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if SIZEOF_VOID_P == 8:
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values = (
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0xABCDEF1234567890,
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0x1234567890ABCDEF,
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0xFEE4ABEDD1CECA5E,
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)
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else:
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values = (
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0x12345678,
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0x1234ABCD,
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0xDEADCAFE,
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)
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for value in values:
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expected = python_hash_pointer(value)
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with self.subTest(value=value):
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self.assertEqual(hash_pointer(value), expected,
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f"hash_pointer({value:x}) = "
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f"{hash_pointer(value):x} != {expected:x}")
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# Py_HashPointer(NULL) returns 0
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self.assertEqual(hash_pointer(0), 0)
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# Py_HashPointer((void*)(uintptr_t)-1) doesn't return -1 but -2
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VOID_P_MAX = -1 & (2 ** (8 * SIZEOF_VOID_P) - 1)
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self.assertEqual(hash_pointer(VOID_P_MAX), -2)
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