diff options
| author | Mark Dickinson <dickinsm@gmail.com> | 2010-05-23 13:33:13 (GMT) |
|---|---|---|
| committer | Mark Dickinson <dickinsm@gmail.com> | 2010-05-23 13:33:13 (GMT) |
| commit | dc787d2055a7b562b64ca91b8f1af6d49fa39f1c (patch) | |
| tree | f6a3868e8134c25c662868f19306bfea76b0ab45 /Include/pyport.h | |
| parent | 03721133a68814696e3eee75b1eb09f5016ff078 (diff) | |
| download | cpython-dc787d2055a7b562b64ca91b8f1af6d49fa39f1c.zip cpython-dc787d2055a7b562b64ca91b8f1af6d49fa39f1c.tar.gz cpython-dc787d2055a7b562b64ca91b8f1af6d49fa39f1c.tar.bz2 | |
Issue #8188: Introduce a new scheme for computing hashes of numbers
(instances of int, float, complex, decimal.Decimal and
fractions.Fraction) that makes it easy to maintain the invariant that
hash(x) == hash(y) whenever x and y have equal value.
Diffstat (limited to 'Include/pyport.h')
| -rw-r--r-- | Include/pyport.h | 14 |
1 files changed, 14 insertions, 0 deletions
diff --git a/Include/pyport.h b/Include/pyport.h index dc5c1fd..9561285 100644 --- a/Include/pyport.h +++ b/Include/pyport.h @@ -126,6 +126,20 @@ Used in: PY_LONG_LONG #endif #endif +/* Parameters used for the numeric hash implementation. See notes for + _PyHash_Double in Objects/object.c. Numeric hashes are based on + reduction modulo the prime 2**_PyHASH_BITS - 1. */ + +#if SIZEOF_LONG >= 8 +#define _PyHASH_BITS 61 +#else +#define _PyHASH_BITS 31 +#endif +#define _PyHASH_MODULUS ((1UL << _PyHASH_BITS) - 1) +#define _PyHASH_INF 314159 +#define _PyHASH_NAN 0 +#define _PyHASH_IMAG 1000003UL + /* 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 * without loss of information. Similarly for intptr_t, wrt a signed |