From: Benjamin Peterson <benjamin@python.org>
Date: Fri, 1 Jan 2016 17:55:47 +0000 (-0600)
Subject: merge 3.3
X-Git-Tag: v3.4.5rc1~44
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=630329e4ea03e01a830e94c06c47027e7886c6dd;p=thirdparty%2FPython%2Fcpython.git

merge 3.3
---

630329e4ea03e01a830e94c06c47027e7886c6dd
diff --cc Objects/setobject.c
index 304519c5d472,fc17fa560ed5..61f1d94e46be
--- a/Objects/setobject.c
+++ b/Objects/setobject.c
@@@ -1,30 -1,7 +1,27 @@@
  
  /* set object implementation
 +
     Written and maintained by Raymond D. Hettinger <python@rcn.com>
     Derived from Lib/sets.py and Objects/dictobject.c.
 +
-    Copyright (c) 2003-2013 Python Software Foundation.
-    All rights reserved.
- 
 +   The basic lookup function used by all operations.
 +   This is based on Algorithm D from Knuth Vol. 3, Sec. 6.4.
 +
 +   The initial probe index is computed as hash mod the table size.
 +   Subsequent probe indices are computed as explained in Objects/dictobject.c.
 +
 +   To improve cache locality, each probe inspects a series of consecutive
 +   nearby entries before moving on to probes elsewhere in memory.  This leaves
 +   us with a hybrid of linear probing and open addressing.  The linear probing
 +   reduces the cost of hash collisions because consecutive memory accesses
 +   tend to be much cheaper than scattered probes.  After LINEAR_PROBES steps,
 +   we then use open addressing with the upper bits from the hash value.  This
 +   helps break-up long chains of collisions.
 +
 +   All arithmetic on hash should ignore overflow.
 +
 +   Unlike the dictionary implementation, the lookkey functions can return
 +   NULL if the rich comparison returns an error.
  */
  
  #include "Python.h"