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ssue #19183: Implement PEP 456 'secure and interchangeable hash algorithm'.

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Python now uses SipHash24 on all major platforms.
This commit is contained in:
Christian Heimes 2013-11-20 11:46:18 +01:00
parent fe32aec25a
commit 985ecdcfc2
27 changed files with 1029 additions and 242 deletions
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35
Objects/unicodeobject.c
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@ -11386,39 +11386,8 @@ unicode_hash(PyObject *self)
_PyUnicode_HASH(self) = 0;
return 0;
}
/* The hash function as a macro, gets expanded three times below. */
#define HASH(P) \
x ^= (Py_uhash_t) *P << 7; \
while (--len >= 0) \
x = (_PyHASH_MULTIPLIER * x) ^ (Py_uhash_t) *P++; \
x = (Py_uhash_t) _Py_HashSecret.prefix;
switch (PyUnicode_KIND(self)) {
case PyUnicode_1BYTE_KIND: {
const unsigned char *c = PyUnicode_1BYTE_DATA(self);
HASH(c);
break;
}
case PyUnicode_2BYTE_KIND: {
const Py_UCS2 *s = PyUnicode_2BYTE_DATA(self);
HASH(s);
break;
}
default: {
Py_UCS4 *l;
assert(PyUnicode_KIND(self) == PyUnicode_4BYTE_KIND &&
"Impossible switch case in unicode_hash");
l = PyUnicode_4BYTE_DATA(self);
HASH(l);
break;
}
}
x ^= (Py_uhash_t) PyUnicode_GET_LENGTH(self);
x ^= (Py_uhash_t) _Py_HashSecret.suffix;
if (x == -1)
x = -2;
x = _Py_HashBytes(PyUnicode_DATA(self),
PyUnicode_GET_LENGTH(self) * PyUnicode_KIND(self));
_PyUnicode_HASH(self) = x;
return x;
}