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| author | Miss Islington (bot) <31488909+miss-islington@users.noreply.github.com> | 2018-01-16 10:27:15 (GMT) |
|---|---|---|
| committer | Raymond Hettinger <rhettinger@users.noreply.github.com> | 2018-01-16 10:27:15 (GMT) |
| commit | e7dbd0658304f11daf103d56662656efecad006d (patch) | |
| tree | 695c10968f5e63a0b5fcc61fc8fbbcf6ad1d49a2 | |
| parent | b92c159efada05b3a5ff9d0dbce3fcb2334631f6 (diff) | |
| download | cpython-e7dbd0658304f11daf103d56662656efecad006d.zip cpython-e7dbd0658304f11daf103d56662656efecad006d.tar.gz cpython-e7dbd0658304f11daf103d56662656efecad006d.tar.bz2 | |
bpo-26163: Frozenset hash improvement (GH-5194) (#5198)
(cherry picked from commit b44c5169f64178d2ff2914187b315549e7ab0cb6)
| -rw-r--r-- | Misc/NEWS.d/next/Core and Builtins/2018-01-14-20-32-47.bpo-26163.xv9Iuv.rst | 2 | ||||
| -rw-r--r-- | Objects/setobject.c | 1 |
2 files changed, 3 insertions, 0 deletions
diff --git a/Misc/NEWS.d/next/Core and Builtins/2018-01-14-20-32-47.bpo-26163.xv9Iuv.rst b/Misc/NEWS.d/next/Core and Builtins/2018-01-14-20-32-47.bpo-26163.xv9Iuv.rst new file mode 100644 index 0000000..163b9e0 --- /dev/null +++ b/Misc/NEWS.d/next/Core and Builtins/2018-01-14-20-32-47.bpo-26163.xv9Iuv.rst @@ -0,0 +1,2 @@ +Improved frozenset() hash to create more distinct hash values when faced +with datasets containing many similar values. diff --git a/Objects/setobject.c b/Objects/setobject.c index 24272b4..093a15f 100644 --- a/Objects/setobject.c +++ b/Objects/setobject.c @@ -790,6 +790,7 @@ frozenset_hash(PyObject *self) hash ^= ((Py_uhash_t)PySet_GET_SIZE(self) + 1) * 1927868237UL; /* Disperse patterns arising in nested frozensets */ + hash ^= (hash >> 11) ^ (~hash >> 25); hash = hash * 69069U + 907133923UL; /* -1 is reserved as an error code */ |