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Consolidate the occurrances of the prime used as the multiplier when hashing.

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This commit is contained in:
Gregory P. Smith 2012-01-14 15:45:13 -08:00
commit f5b62a9b31
4 changed files with 7 additions and 4 deletions
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5
Include/pyport.h
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@ -131,6 +131,9 @@ Used in: PY_LONG_LONG
#endif #endif
#endif #endif
/* Prime multiplier used in string and various other hashes. */
#define _PyHASH_MULTIPLIER 1000003 /* 0xf4243 */
/* Parameters used for the numeric hash implementation. See notes for /* Parameters used for the numeric hash implementation. See notes for
_Py_HashDouble in Objects/object.c. Numeric hashes are based on _Py_HashDouble in Objects/object.c. Numeric hashes are based on
reduction modulo the prime 2**_PyHASH_BITS - 1. */ reduction modulo the prime 2**_PyHASH_BITS - 1. */
@ -143,7 +146,7 @@ Used in: PY_LONG_LONG
#define _PyHASH_MODULUS (((size_t)1 << _PyHASH_BITS) - 1) #define _PyHASH_MODULUS (((size_t)1 << _PyHASH_BITS) - 1)
#define _PyHASH_INF 314159 #define _PyHASH_INF 314159
#define _PyHASH_NAN 0 #define _PyHASH_NAN 0
#define _PyHASH_IMAG 1000003UL #define _PyHASH_IMAG _PyHASH_MULTIPLIER
/* uintptr_t is the C9X name for an unsigned integral type such that a /* uintptr_t is the C9X name for an unsigned integral type such that a
* legitimate void* can be cast to uintptr_t and then back to void* again * legitimate void* can be cast to uintptr_t and then back to void* again

2
Objects/object.c
View file

@ -761,7 +761,7 @@ _Py_HashBytes(unsigned char *p, Py_ssize_t len)
x = (Py_uhash_t) *p << 7; x = (Py_uhash_t) *p << 7;
for (i = 0; i < len; i++) for (i = 0; i < len; i++)
x = (1000003U * x) ^ (Py_uhash_t) *p++; x = (_PyHASH_MULTIPLIER * x) ^ (Py_uhash_t) *p++;
x ^= (Py_uhash_t) len; x ^= (Py_uhash_t) len;
if (x == -1) if (x == -1)
x = -2; x = -2;

2
Objects/tupleobject.c
View file

@ -316,7 +316,7 @@ tuplehash(PyTupleObject *v)
register Py_hash_t y; register Py_hash_t y;
register Py_ssize_t len = Py_SIZE(v); register Py_ssize_t len = Py_SIZE(v);
register PyObject **p; register PyObject **p;
Py_uhash_t mult = 1000003; Py_uhash_t mult = _PyHASH_MULTIPLIER;
x = 0x345678; x = 0x345678;
p = v->ob_item; p = v->ob_item;
while (--len >= 0) { while (--len >= 0) {

2
Objects/unicodeobject.c
View file

@ -11210,7 +11210,7 @@ unicode_hash(PyObject *self)
#define HASH(P) \ #define HASH(P) \
x = (Py_uhash_t)*P << 7; \ x = (Py_uhash_t)*P << 7; \
while (--len >= 0) \ while (--len >= 0) \
x = (1000003*x) ^ (Py_uhash_t)*P++; x = (_PyHASH_MULTIPLIER*x) ^ (Py_uhash_t)*P++;
switch (PyUnicode_KIND(self)) { switch (PyUnicode_KIND(self)) {
case PyUnicode_1BYTE_KIND: { case PyUnicode_1BYTE_KIND: {