From 13634cf7a407202777285172a57cfcddb20a2047 Mon Sep 17 00:00:00 2001 From: Fred Drake Date: Thu, 29 Jun 2000 19:17:04 +0000 Subject: This patch addresses two main issues: (1) There exist some non-fatal errors in some of the hash algorithms. For exmaple, in float_hash and complex_hash a certain part of the value is not included in the hash calculation. See Tim's, Guido's, and my discussion of this on python-dev in May under the title "fix float_hash and complex_hash for 64-bit *nix" (2) The hash algorithms that use pointers (e.g. func_hash, code_hash) are universally not correct on Win64 (they assume that sizeof(long) == sizeof(void*)) As well, this patch significantly cleans up the hash code. It adds the two function _Py_HashDouble and _PyHash_VoidPtr that the various hashing routine are changed to use. These help maintain the hash function invariant: (a==b) => (hash(a)==hash(b))) I have added Lib/test/test_hash.py and Lib/test/output/test_hash to test this for some cases. --- Objects/complexobject.c | 37 +++++++++---------------------------- 1 file changed, 9 insertions(+), 28 deletions(-) (limited to 'Objects/complexobject.c') diff --git a/Objects/complexobject.c b/Objects/complexobject.c index 42709ee09a..1a15a27ebd 100644 --- a/Objects/complexobject.c +++ b/Objects/complexobject.c @@ -285,8 +285,7 @@ complex_hash(v) PyComplexObject *v; { double intpart, fractpart; - int expo; - long hipart, x; + long x; /* This is designed so that Python numbers with the same value hash to the same value, otherwise comparisons of mapping keys will turn out weird */ @@ -302,7 +301,7 @@ complex_hash(v) #endif if (fractpart == 0.0 && v->cval.imag == 0.0) { - if (intpart > 0x7fffffffL || -intpart > 0x7fffffffL) { + if (intpart > LONG_MAX || -intpart > LONG_MAX) { /* Convert to long int and use its hash... */ PyObject *w = PyLong_FromDouble(v->cval.real); if (w == NULL) @@ -314,36 +313,18 @@ complex_hash(v) x = (long)intpart; } else { - fractpart = frexp(fractpart, &expo); - fractpart = fractpart * 2147483648.0; /* 2**31 */ - hipart = (long)fractpart; /* Take the top 32 bits */ - fractpart = (fractpart - (double)hipart) * 2147483648.0; - /* Get the next 32 bits */ - x = hipart + (long)fractpart + (long)intpart + (expo << 15); - /* Combine everything */ + x = _Py_HashDouble(v->cval.real); + if (x == -1) + return -1; if (v->cval.imag != 0.0) { /* Hash the imaginary part */ /* XXX Note that this hashes complex(x, y) to the same value as complex(y, x). Still better than it used to be :-) */ -#ifdef MPW - { - extended e; - fractpart = modf(v->cval.imag, &e); - intpart = e; - } -#else - fractpart = modf(v->cval.imag, &intpart); -#endif - fractpart = frexp(fractpart, &expo); - fractpart = fractpart * 2147483648.0; /* 2**31 */ - hipart = (long)fractpart; /* Take the top 32 bits */ - fractpart = - (fractpart - (double)hipart) * 2147483648.0; - /* Get the next 32 bits */ - x ^= hipart + (long)fractpart + - (long)intpart + (expo << 15); - /* Combine everything */ + long y = _Py_HashDouble(v->cval.imag); + if (y == -1) + return -1; + x += y; } } if (x == -1) -- cgit v1.2.1