Added check to make sure BTreeItems objects don't segfault by

exceeding underlying BTree data because BTree items were deleted
since the BTreeItems object was deleted.

Note that accessing BTreeItems elements could give incorrect
results if BTree items are deleted after creating a BTreeItems
object.

lib/Components/BTree/BTree.c

@@ -85,7 +85,7 @@
 
 static char BTree_module_documentation[] = 
 ""
-"\n$Id: BTree.c,v 1.22 1999/06/10 20:29:41 jim Exp $"
+"\n$Id: BTree.c,v 1.23 1999/06/23 22:49:08 jim Exp $"
 ;
 
 #define PERSISTENT
@@ -283,7 +283,8 @@ BTreeItems_item(BTreeItems *self, int i)
   j=i;
   l=self->len;
   if(j < 0) j += l;
-  if(j < 0 || j >= l)
+  i=j+self->first;
+  if(j < 0 || j >= l || i >= self->data->count)
     {
       PyObject *v;
       v=PyInt_FromLong(i);
@@ -296,7 +297,6 @@ BTreeItems_item(BTreeItems *self, int i)
       Py_DECREF(v);
       return NULL;
     }
-  i=j+self->first;
 
   return BTreeItems_item_BTree(self->kind, i, self->data);
 }
@@ -1842,7 +1842,7 @@ initBTree()
 #endif
 {
   PyObject *m, *d;
-  char *rev="$Revision: 1.22 $";
+  char *rev="$Revision: 1.23 $";
 
   UNLESS(PyExtensionClassCAPI=PyCObject_Import("ExtensionClass","CAPI"))
       return;