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GH-84783: Make the slice object hashable (GH-101264)

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Furkan Onder 2023-02-19 00:22:02 +00:00 • committed by GitHub
parent 5170caf305
commit 61f1e67c6f
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7 changed files with 53 additions and 12 deletions
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38
Objects/sliceobject.c
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@ -628,6 +628,42 @@ slice_traverse(PySliceObject *v, visitproc visit, void *arg)
return 0;
}
/* code based on tuplehash() of Objects/tupleobject.c */
#if SIZEOF_PY_UHASH_T > 4
#define _PyHASH_XXPRIME_1 ((Py_uhash_t)11400714785074694791ULL)
#define _PyHASH_XXPRIME_2 ((Py_uhash_t)14029467366897019727ULL)
#define _PyHASH_XXPRIME_5 ((Py_uhash_t)2870177450012600261ULL)
#define _PyHASH_XXROTATE(x) ((x << 31) | (x >> 33)) /* Rotate left 31 bits */
#else
#define _PyHASH_XXPRIME_1 ((Py_uhash_t)2654435761UL)
#define _PyHASH_XXPRIME_2 ((Py_uhash_t)2246822519UL)
#define _PyHASH_XXPRIME_5 ((Py_uhash_t)374761393UL)
#define _PyHASH_XXROTATE(x) ((x << 13) | (x >> 19)) /* Rotate left 13 bits */
#endif
static Py_hash_t
slicehash(PySliceObject *v)
{
Py_uhash_t acc = _PyHASH_XXPRIME_5;
#define _PyHASH_SLICE_PART(com) { \
Py_uhash_t lane = PyObject_Hash(v->com); \
if(lane == (Py_uhash_t)-1) { \
return -1; \
} \
acc += lane * _PyHASH_XXPRIME_2; \
acc = _PyHASH_XXROTATE(acc); \
acc *= _PyHASH_XXPRIME_1; \
}
_PyHASH_SLICE_PART(start);
_PyHASH_SLICE_PART(stop);
_PyHASH_SLICE_PART(step);
#undef _PyHASH_SLICE_PART
if(acc == (Py_uhash_t)-1) {
return 1546275796;
}
return acc;
}
PyTypeObject PySlice_Type = {
PyVarObject_HEAD_INIT(&PyType_Type, 0)
"slice", /* Name of this type */
@ -642,7 +678,7 @@ PyTypeObject PySlice_Type = {
0, /* tp_as_number */
0, /* tp_as_sequence */
0, /* tp_as_mapping */
PyObject_HashNotImplemented, /* tp_hash */
(hashfunc)slicehash, /* tp_hash */
0, /* tp_call */
0, /* tp_str */
PyObject_GenericGetAttr, /* tp_getattro */