[pypy-svn] r15383 - pypy/dist/pypy/objspace/std

[arigo at codespeak.net]

Author: arigo
Date: Fri Jul 29 22:53:21 2005
New Revision: 15383

Modified:
   pypy/dist/pypy/objspace/std/dictobject.py
Log:
Don't use '%' in W_DictObject.  Better use '&' masking, as we know the hash
table's length is a power of two.  Additionally, genc doesn't know about '/'
and '%' on r_uint...


Modified: pypy/dist/pypy/objspace/std/dictobject.py
==============================================================================
--- pypy/dist/pypy/objspace/std/dictobject.py	(original)
+++ pypy/dist/pypy/objspace/std/dictobject.py	Fri Jul 29 22:53:21 2005
@@ -65,7 +65,8 @@
         assert isinstance(lookup_hash, r_uint)
         space = self.space
         data = self.data
-        i = lookup_hash % len(data)
+        mask = len(data) - 1   # len(data) is expected to be a power of 2
+        i = lookup_hash & mask
 
         entry = data[i]
         if entry.w_key is None or space.is_w(w_lookup, entry.w_key):
@@ -85,7 +86,7 @@
         perturb = lookup_hash
         while 1:
             i = (i << 2) + i + perturb + 1
-            entry = data[i%len(data)]
+            entry = data[i & mask]
             if entry.w_key is None:
                 if freeslot:
                     return freeslot