Fix for http://sourceforge.net/bugs/?func=detailbug&bug_id=111866&group_id=5470.
This was a misleading bug -- the true "bug" was that hash(x) gave an error
return when x is an infinity. Fixed that. Added new Py_IS_INFINITY macro to
pyport.h. Rearranged code to reduce growing duplication in hashing of float and
complex numbers, pushing Trent's earlier stab at that to a logical conclusion.
Fixed exceedingly rare bug where hashing of floats could return -1 even if there
wasn't an error (didn't waste time trying to construct a test case, it was simply
obvious from the code that it *could* happen). Improved complex hash so that
hash(complex(x, y)) doesn't systematically equal hash(complex(y, x)) anymore.
diff --git a/Include/pyport.h b/Include/pyport.h
index 3d9b305..5bd641c 100644
--- a/Include/pyport.h
+++ b/Include/pyport.h
@@ -103,7 +103,7 @@
#define Py_ARITHMETIC_RIGHT_SHIFT(TYPE, I, J) ((I) >> (J))
#endif
-/* Py_FORCE_EXPANSION
+/* Py_FORCE_EXPANSION(X)
* "Simply" returns its argument. However, macro expansions within the
* argument are evaluated. This unfortunate trickery is needed to get
* token-pasting to work as desired in some cases.
@@ -123,6 +123,14 @@
#define Py_SAFE_DOWNCAST(VALUE, WIDE, NARROW) (NARROW)(VALUE)
#endif
+/* Py_IS_INFINITY(X)
+ * Return 1 if float or double arg is an infinity, else 0.
+ * Caution:
+ * X is evaluated more than once.
+ * This implementation may set the underflow flag if |X| is very small;
+ * it really can't be implemented correctly (& easily) before C99.
+ */
+ #define Py_IS_INFINITY(X) ((X) && (X)*0.5 == (X))
/**************************************************************************
Prototypes that are missing from the standard include files on some systems