SF patch #907403: Improvements to cStringIO.writelines()
The writelines() method now accepts any iterable argument and writes
the lines one at a time rather than using ''.join(lines) followed by
a single write. Results in considerable memory savings and makes
the method suitable for use with generator expressions.
diff --git a/Modules/cStringIO.c b/Modules/cStringIO.c
index 4ec5e88..1420bce 100644
--- a/Modules/cStringIO.c
+++ b/Modules/cStringIO.c
@@ -416,40 +416,35 @@
return Py_None;
}
-
PyDoc_STRVAR(O_writelines__doc__,
-"writelines(sequence_of_strings): write each string");
+"writelines(sequence_of_strings) -> None. Write the strings to the file.\n"
+"\n"
+"Note that newlines are not added. The sequence can be any iterable object\n"
+"producing strings. This is equivalent to calling write() for each string.");
static PyObject *
O_writelines(Oobject *self, PyObject *args) {
- PyObject *tmp = 0;
- static PyObject *joiner = NULL;
-
- if (!joiner) {
- PyObject *empty_string = PyString_FromString("");
- if (empty_string == NULL)
- return NULL;
- joiner = PyObject_GetAttrString(empty_string, "join");
- Py_DECREF(empty_string);
- if (joiner == NULL)
- return NULL;
- }
-
- if (PyObject_Size(args) < 0) return NULL;
-
- args = PyTuple_Pack(1, args);
- if (args == NULL)
+ PyObject *it, *s;
+
+ it = PyObject_GetIter(args);
+ if (it == NULL)
return NULL;
- tmp = PyObject_Call(joiner, args, NULL);
- Py_DECREF(args);
- UNLESS (tmp) return NULL;
-
- args = PyTuple_Pack(1, tmp);
- Py_DECREF(tmp);
- UNLESS (args) return NULL;
-
- tmp = O_write(self, args);
- Py_DECREF(args);
- return tmp;
+ while ((s = PyIter_Next(it)) != NULL) {
+ int n;
+ char *c;
+ if (PyString_AsStringAndSize(s, &c, &n) == -1) {
+ Py_DECREF(it);
+ Py_DECREF(s);
+ return NULL;
+ }
+ if (O_cwrite((PyObject *)self, c, n) == -1) {
+ Py_DECREF(it);
+ Py_DECREF(s);
+ return NULL;
+ }
+ Py_DECREF(s);
+ }
+ Py_DECREF(it);
+ Py_RETURN_NONE;
}
static struct PyMethodDef O_methods[] = {