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* Simplify and speed-up list_resize(). Relying on the newly documented

Browse source 
invariants allows the ob_item != NULL check to be replaced with an
  assertion.

* Added assertions to list_init() which document and verify that the
  tp_new slot establishes the invariants.  This may preclude a future
  bug if a custom tp_new slot is written.
This commit is contained in:
Raymond Hettinger 2004-07-29 23:31:29 +00:00
parent 93677f075d
commit c0aaa2db4f
1 changed files with 7 additions and 3 deletions
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10
Objects/listobject.c
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@ -19,9 +19,8 @@ list_resize(PyListObject *self, int newsize)
current size, then proceed with the realloc() to shrink the list. current size, then proceed with the realloc() to shrink the list.
*/ */
if (self->allocated >= newsize && if (self->allocated >= newsize && self->ob_size < newsize + 16) {
self->ob_size < newsize + 16 && assert(self->ob_item != NULL || newsize == 0);
self->ob_item != NULL) {
self->ob_size = newsize; self->ob_size = newsize;
return 0; return 0;
} }
@ -2314,6 +2313,11 @@ list_init(PyListObject *self, PyObject *args, PyObject *kw)
if (!PyArg_ParseTupleAndKeywords(args, kw, "|O:list", kwlist, &arg)) if (!PyArg_ParseTupleAndKeywords(args, kw, "|O:list", kwlist, &arg))
return -1; return -1;
/* Verify list invariants established by PyType_GenericAlloc() */
assert(0 <= self->ob_size && self->ob_size <= self->allocated);
assert(self->ob_item != NULL || self->allocated == 0);
/* Empty previous contents */ /* Empty previous contents */
if (self->ob_item != NULL) { if (self->ob_item != NULL) {
(void)list_clear(self); (void)list_clear(self);