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.

2 files changed, 27 insertions, 0 deletions

diff --git a/Lib/test/output/test_hash b/Lib/test/output/test_hash
new file mode 100644
index 0000000..0141a1a
--- /dev/null
+++ b/Lib/test/output/test_hash
@@ -0,0 +1 @@
+test_hash
diff --git a/Lib/test/test_hash.py b/Lib/test/test_hash.py
new file mode 100644
index 0000000..51b4c33
--- /dev/null
+++ b/Lib/test/test_hash.py
@@ -0,0 +1,26 @@
+# test the invariant that
+#   iff a==b then hash(a)==hash(b)
+#
+
+import test_support
+
+
+def same_hash(*objlist):
+	# hash each object given an raise TestFailed if
+	# the hash values are not all the same
+	hashed = map(hash, objlist)
+	for h in hashed[1:]:
+		if h != hashed[0]:
+			raise TestFailed, "hashed values differ: %s" % `objlist`
+
+
+
+same_hash(1, 1L, 1.0, 1.0+0.0j)
+same_hash(int(1), long(1), float(1), complex(1))
+
+same_hash(long(1.23e300), float(1.23e300))
+
+same_hash(float(0.5), complex(0.5, 0.0))
+
+
+