Implemented list batching in cPickle.
diff --git a/Modules/cPickle.c b/Modules/cPickle.c
index 5452713..a35905d 100644
--- a/Modules/cPickle.c
+++ b/Modules/cPickle.c
@@ -87,6 +87,11 @@
#undef FALSE
#define FALSE "I00\n"
+/* Keep in synch with pickle.Pickler._BATCHSIZE. This is how many elements
+ * batch_{list, dict} pump out before doing APPENDS/SETITEMS.
+ */
+#define BATCHSIZE 1000
+
static char MARKv = MARK;
static PyObject *PickleError;
@@ -1614,34 +1619,119 @@
return res;
}
+/* iter is an iterator giving items, and we batch up chunks of
+ * MARK item item ... item APPENDS
+ * opcode sequences. Calling code should have arranged to first create an
+ * empty list, or list-like object, for the APPENDS to operate on.
+ * Returns 0 on success, <0 on error.
+ */
+static int
+batch_list(Picklerobject *self, PyObject *iter)
+{
+ PyObject *obj;
+ PyObject *slice[BATCHSIZE];
+ int i, n;
+
+ static char append = APPEND;
+ static char appends = APPENDS;
+
+ assert(iter != NULL);
+
+ if (self->proto == 0) {
+ /* APPENDS isn't available; do one at a time. */
+ for (;;) {
+ obj = PyIter_Next(iter);
+ if (obj == NULL) {
+ if (PyErr_Occurred())
+ return -1;
+ break;
+ }
+ i = save(self, obj, 0);
+ Py_DECREF(obj);
+ if (i < 0)
+ return -1;
+ if (self->write_func(self, &append, 1) < 0)
+ return -1;
+
+ }
+ return 0;
+ }
+
+ /* proto > 0: write in batches of BATCHSIZE. */
+ do {
+ /* Get next group of (no more than) BATCHSIZE elements. */
+ for (n = 0; n < BATCHSIZE; ++n) {
+ obj = PyIter_Next(iter);
+ if (obj == NULL) {
+ if (PyErr_Occurred())
+ goto BatchFailed;
+ break;
+ }
+ slice[n] = obj;
+ }
+
+ if (n > 1) {
+ /* Pump out MARK, slice[0:n], APPENDS. */
+ if (self->write_func(self, &MARKv, 1) < 0)
+ goto BatchFailed;
+ for (i = 0; i < n; ++i) {
+ if (save(self, slice[i], 0) < 0)
+ goto BatchFailed;
+ }
+ if (self->write_func(self, &appends, 1) < 0)
+ goto BatchFailed;
+ }
+ else if (n == 1) {
+ if (save(self, slice[0], 0) < 0)
+ goto BatchFailed;
+ if (self->write_func(self, &append, 1) < 0)
+ goto BatchFailed;
+ }
+
+ for (i = 0; i < n; ++i) {
+ Py_DECREF(slice[i]);
+ }
+ }while (n == BATCHSIZE);
+ return 0;
+
+BatchFailed:
+ while (--n >= 0) {
+ Py_DECREF(slice[n]);
+ }
+ return -1;
+}
+
static int
save_list(Picklerobject *self, PyObject *args)
{
- PyObject *element = 0;
- int s_len, len, i, using_appends, res = -1;
+ int res = -1;
char s[3];
+ int len;
+ PyObject *iter;
- static char append = APPEND, appends = APPENDS;
if (self->fast && !fast_save_enter(self, args))
goto finally;
+ /* Create an empty list. */
if (self->bin) {
s[0] = EMPTY_LIST;
- s_len = 1;
+ len = 1;
}
else {
s[0] = MARK;
s[1] = LIST;
- s_len = 2;
+ len = 2;
}
+ if (self->write_func(self, s, len) < 0)
+ goto finally;
+
+ /* Get list length, and bow out early if empty. */
if ((len = PyList_Size(args)) < 0)
goto finally;
- if (self->write_func(self, s, s_len) < 0)
- goto finally;
-
+ /* Memoize. */
if (len == 0) {
if (put(self, args) < 0)
goto finally;
@@ -1651,29 +1741,12 @@
goto finally;
}
- if ((using_appends = (self->bin && (len > 1))))
- if (self->write_func(self, &MARKv, 1) < 0)
- goto finally;
-
- for (i = 0; i < len; i++) {
- if (!( element = PyList_GET_ITEM((PyListObject *)args, i)))
- goto finally;
-
- if (save(self, element, 0) < 0)
- goto finally;
-
- if (!using_appends) {
- if (self->write_func(self, &append, 1) < 0)
- goto finally;
- }
- }
-
- if (using_appends) {
- if (self->write_func(self, &appends, 1) < 0)
- goto finally;
- }
-
- res = 0;
+ /* Materialize the list elements. */
+ iter = PyObject_GetIter(args);
+ if (iter == NULL)
+ goto finally;
+ res = batch_list(self, iter);
+ Py_DECREF(iter);
finally:
if (self->fast && !fast_save_leave(self, args))