[pypy-svn] r10274 - pypy/dist/pypy/objspace/std

[tismer at codespeak.net]

Author: tismer
Date: Sun Apr  3 22:06:44 2005
New Revision: 10274

Modified:
   pypy/dist/pypy/objspace/std/listobject.py
Log:
a _del_slice that seems to be solid against desctruction side-effects,
not depending on the life time of local variables.
The issue might come up, again, if we decide to change array size
on changing w_list.w_size, of course.

Modified: pypy/dist/pypy/objspace/std/listobject.py
==============================================================================
--- pypy/dist/pypy/objspace/std/listobject.py	(original)
+++ pypy/dist/pypy/objspace/std/listobject.py	Sun Apr  3 22:06:44 2005
@@ -439,16 +439,21 @@
         ihigh = w_list.ob_size
     items = w_list.ob_item
     d = ihigh-ilow
-    # keep a reference to the objects to be removed,
     # preventing side effects during destruction
-    recycle = [items[i] for i in range(ilow, ihigh)]
-    for i in range(ilow, w_list.ob_size - d):
+    # first, re-arrange the list so unused elements are at the end.
+    newsize = w_list.ob_size - d
+    for i in range(ilow, newsize):
+        hold = items[i]
         items[i] = items[i+d]
-        items[i+d] = None
-    w_list.ob_size -= d
-    # set the unused items to None to make sure the objects are freed
-    for i in range(w_list.ob_size, ilow+d):
-        items[i] = None
+        items[i+d] = hold
+    # now get rid of the objects at the end, always
+    # keeping the list consistent
+    while w_list.ob_size > newsize:
+        p = w_list.ob_size-1
+        hold = w_list.ob_item[p]
+        w_list.ob_size = p
+        w_list.ob_item[p] = None
+        del hold
 
 # note that the default value will come back wrapped!!!
 def list_pop__List_ANY(space, w_list, w_idx=-1):