mirrors/cpython
1
0
Fork 0
mirror of https://github.com/python/cpython.git synced 2025-10-03 13:45:29 +00:00
Code Issues Projects Releases Packages Wiki Activity Actions 8

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

Browse source 
to a single #define instead of having several copies in several files.

This excludes the Modules/ tree (datetime and expat both have a copy
for their own purposes with no need for it to be the same).
This commit is contained in:
Gregory P. Smith 2012-01-14 15:31:34 -08:00
parent 515687a7ed
commit 63e6c3222f
4 changed files with 7 additions and 4 deletions
Download patch file Download diff file Expand all files Collapse all files

5
Include/pyport.h
View file

@ -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
_PyHash_Double in Objects/object.c. Numeric hashes are based on _PyHash_Double 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/bytesobject.c
View file

@ -881,7 +881,7 @@ bytes_hash(PyBytesObject *a)
p = (unsigned char *) a->ob_sval; p = (unsigned char *) a->ob_sval;
x = *p << 7; x = *p << 7;
while (--len >= 0) while (--len >= 0)
x = (1000003*x) ^ *p++; x = (_PyHASH_MULTIPLIER*x) ^ *p++;
x ^= Py_SIZE(a); x ^= Py_SIZE(a);
if (x == -1) if (x == -1)
x = -2; x = -2;

2
Objects/tupleobject.c
View file

@ -315,7 +315,7 @@ tuplehash(PyTupleObject *v)
register Py_hash_t x, y; register Py_hash_t x, y;
register Py_ssize_t len = Py_SIZE(v); register Py_ssize_t len = Py_SIZE(v);
register PyObject **p; register PyObject **p;
Py_hash_t mult = 1000003L; Py_hash_t mult = _PyHASH_MULTIPLIER;
x = 0x345678L; x = 0x345678L;
p = v->ob_item; p = v->ob_item;
while (--len >= 0) { while (--len >= 0) {

2
Objects/unicodeobject.c
View file

@ -7666,7 +7666,7 @@ unicode_hash(PyUnicodeObject *self)
p = self->str; p = self->str;
x = *p << 7; x = *p << 7;
while (--len >= 0) while (--len >= 0)
x = (1000003*x) ^ *p++; x = (_PyHASH_MULTIPLIER*x) ^ *p++;
x ^= Py_SIZE(self); x ^= Py_SIZE(self);
if (x == -1) if (x == -1)
x = -2; x = -2;