Add itertools.accumulate().
diff --git a/Modules/itertoolsmodule.c b/Modules/itertoolsmodule.c
index d5336f2..04bfffc 100644
--- a/Modules/itertoolsmodule.c
+++ b/Modules/itertoolsmodule.c
@@ -2584,6 +2584,146 @@
PyObject_GC_Del, /* tp_free */
};
+/* accumulate object ************************************************************/
+
+typedef struct {
+ PyObject_HEAD
+ PyObject *total;
+ PyObject *it;
+} accumulateobject;
+
+static PyTypeObject accumulate_type;
+
+static PyObject *
+accumulate_new(PyTypeObject *type, PyObject *args, PyObject *kwds)
+{
+ static char *kwargs[] = {"iterable", "start", NULL};
+ PyObject *iterable;
+ PyObject *it;
+ PyObject *start = NULL;
+ accumulateobject *lz;
+
+ if (!PyArg_ParseTupleAndKeywords(args, kwds, "O|O:accumulate",
+ kwargs, &iterable, &start))
+ return NULL;
+
+ /* Get iterator. */
+ it = PyObject_GetIter(iterable);
+ if (it == NULL)
+ return NULL;
+
+ /* Default start value */
+ if (start == NULL) {
+ start = PyLong_FromLong(0);
+ if (start == NULL) {
+ Py_DECREF(it);
+ return NULL;
+ }
+ } else {
+ Py_INCREF(start);
+ }
+
+ /* create accumulateobject structure */
+ lz = (accumulateobject *)type->tp_alloc(type, 0);
+ if (lz == NULL) {
+ Py_DECREF(it);
+ Py_DECREF(start);
+ return NULL;
+ }
+
+ lz->total = start;
+ lz->it = it;
+ return (PyObject *)lz;
+}
+
+static void
+accumulate_dealloc(accumulateobject *lz)
+{
+ PyObject_GC_UnTrack(lz);
+ Py_XDECREF(lz->total);
+ Py_XDECREF(lz->it);
+ Py_TYPE(lz)->tp_free(lz);
+}
+
+static int
+accumulate_traverse(accumulateobject *lz, visitproc visit, void *arg)
+{
+ Py_VISIT(lz->it);
+ Py_VISIT(lz->total);
+ return 0;
+}
+
+static PyObject *
+accumulate_next(accumulateobject *lz)
+{
+ PyObject *val, *oldtotal, *newtotal;
+
+ val = PyIter_Next(lz->it);
+ if (val == NULL)
+ return NULL;
+
+ newtotal = PyNumber_Add(lz->total, val);
+ Py_DECREF(val);
+ if (newtotal == NULL)
+ return NULL;
+
+ oldtotal = lz->total;
+ lz->total = newtotal;
+ Py_DECREF(oldtotal);
+
+ Py_INCREF(newtotal);
+ return newtotal;
+}
+
+PyDoc_STRVAR(accumulate_doc,
+"accumulate(iterable, start=0) --> accumulate object\n\
+\n\
+Return series of accumulated sums.");
+
+static PyTypeObject accumulate_type = {
+ PyVarObject_HEAD_INIT(NULL, 0)
+ "itertools.accumulate", /* tp_name */
+ sizeof(accumulateobject), /* tp_basicsize */
+ 0, /* tp_itemsize */
+ /* methods */
+ (destructor)accumulate_dealloc, /* tp_dealloc */
+ 0, /* tp_print */
+ 0, /* tp_getattr */
+ 0, /* tp_setattr */
+ 0, /* tp_reserved */
+ 0, /* tp_repr */
+ 0, /* tp_as_number */
+ 0, /* tp_as_sequence */
+ 0, /* tp_as_mapping */
+ 0, /* tp_hash */
+ 0, /* tp_call */
+ 0, /* tp_str */
+ PyObject_GenericGetAttr, /* tp_getattro */
+ 0, /* tp_setattro */
+ 0, /* tp_as_buffer */
+ Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC |
+ Py_TPFLAGS_BASETYPE, /* tp_flags */
+ accumulate_doc, /* tp_doc */
+ (traverseproc)accumulate_traverse, /* tp_traverse */
+ 0, /* tp_clear */
+ 0, /* tp_richcompare */
+ 0, /* tp_weaklistoffset */
+ PyObject_SelfIter, /* tp_iter */
+ (iternextfunc)accumulate_next, /* tp_iternext */
+ 0, /* tp_methods */
+ 0, /* tp_members */
+ 0, /* tp_getset */
+ 0, /* tp_base */
+ 0, /* tp_dict */
+ 0, /* tp_descr_get */
+ 0, /* tp_descr_set */
+ 0, /* tp_dictoffset */
+ 0, /* tp_init */
+ 0, /* tp_alloc */
+ accumulate_new, /* tp_new */
+ PyObject_GC_Del, /* tp_free */
+};
+
/* compress object ************************************************************/
@@ -3496,6 +3636,7 @@
repeat(elem [,n]) --> elem, elem, elem, ... endlessly or up to n times\n\
\n\
Iterators terminating on the shortest input sequence:\n\
+accumulate(p, start=0) --> p0, p0+p1, p0+p1+p2\n\
chain(p, q, ...) --> p0, p1, ... plast, q0, q1, ... \n\
compress(data, selectors) --> (d[0] if s[0]), (d[1] if s[1]), ...\n\
dropwhile(pred, seq) --> seq[n], seq[n+1], starting when pred fails\n\
@@ -3541,6 +3682,7 @@
PyObject *m;
char *name;
PyTypeObject *typelist[] = {
+ &accumulate_type,
&combinations_type,
&cwr_type,
&cycle_type,