diff -r 1f3242fb0c9c Modules/sha256module.c
--- a/Modules/sha256module.c	Thu Jan 09 19:03:32 2014 -0500
+++ b/Modules/sha256module.c	Fri Jan 10 15:26:43 2014 +0800
@@ -36,6 +36,17 @@
 #define SHA_BLOCKSIZE    64
 #define SHA_DIGESTSIZE  32
 
+/*[clinic input]
+module _sha256
+class _sha256.SHA256
+[clinic start generated code]*/
+/*[clinic end generated code: checksum=da39a3ee5e6b4b0d3255bfef95601890afd80709]*/
+/*[python input]
+class SHAobject_converter(self_converter):
+    type = "SHAobject *"
+[python start generated code]*/
+/*[python end generated code: checksum=da39a3ee5e6b4b0d3255bfef95601890afd80709]*/
+
 /* The structure for storing SHA info */
 
 typedef struct {
@@ -462,18 +473,28 @@
     return retval;
 }
 
-PyDoc_STRVAR(SHA256_update__doc__,
-"Update this hash object's state with the provided string.");
+/*[clinic input]
+_sha256.SHA256.update
+    self: SHAobject
+    obj: object
+    /
+
+Update this hash object's state with the provided string.
+[clinic start generated code]*/
+
+PyDoc_STRVAR(_sha256_SHA256_update__doc__,
+"update(obj)\n"
+"Update this hash object\'s state with the provided string.");
+
+#define _SHA256_SHA256_UPDATE_METHODDEF    \
+    {"update", (PyCFunction)_sha256_SHA256_update, METH_O, _sha256_SHA256_update__doc__},
 
 static PyObject *
-SHA256_update(SHAobject *self, PyObject *args)
+_sha256_SHA256_update(SHAobject *self, PyObject *obj)
+/*[clinic end generated code: checksum=52c21735e19c8d9455303732eda5e5c1c7adb60e]*/
 {
-    PyObject *obj;
     Py_buffer buf;
 
-    if (!PyArg_ParseTuple(args, "O:update", &obj))
-        return NULL;
-
     GET_BUFFER_VIEW_OR_ERROUT(obj, &buf);
 
     sha_update(self, buf.buf, buf.len);
@@ -487,7 +508,7 @@
     {"copy",      (PyCFunction)SHA256_copy,      METH_NOARGS,  SHA256_copy__doc__},
     {"digest",    (PyCFunction)SHA256_digest,    METH_NOARGS,  SHA256_digest__doc__},
     {"hexdigest", (PyCFunction)SHA256_hexdigest, METH_NOARGS,  SHA256_hexdigest__doc__},
-    {"update",    (PyCFunction)SHA256_update,    METH_VARARGS, SHA256_update__doc__},
+    _SHA256_SHA256_UPDATE_METHODDEF
     {NULL,        NULL}         /* sentinel */
 };
 
@@ -594,27 +615,53 @@
 
 /* The single module-level function: new() */
 
-PyDoc_STRVAR(SHA256_new__doc__,
+/*[clinic input]
+_sha256.SHA256.sha256
+
+    string: object = None
+
+Return a new SHA-256 hash object; optionally initialized with a string.
+[clinic start generated code]*/
+
+PyDoc_STRVAR(_sha256_SHA256_sha256__doc__,
+"sha256(string=None)\n"
 "Return a new SHA-256 hash object; optionally initialized with a string.");
 
+#define _SHA256_SHA256_SHA256_METHODDEF    \
+    {"sha256", (PyCFunction)_sha256_SHA256_sha256, METH_VARARGS|METH_KEYWORDS, _sha256_SHA256_sha256__doc__},
+
 static PyObject *
-SHA256_new(PyObject *self, PyObject *args, PyObject *kwdict)
+_sha256_SHA256_sha256_impl(PyObject *self, PyObject *string);
+
+static PyObject *
+_sha256_SHA256_sha256(PyObject *self, PyObject *args, PyObject *kwargs)
 {
-    static char *kwlist[] = {"string", NULL};
+    PyObject *return_value = NULL;
+    static char *_keywords[] = {"string", NULL};
+    PyObject *string = Py_None;
+
+    if (!PyArg_ParseTupleAndKeywords(args, kwargs,
+        "|O:sha256", _keywords,
+        &string))
+        goto exit;
+    return_value = _sha256_SHA256_sha256_impl(self, string);
+
+exit:
+    return return_value;
+}
+
+static PyObject *
+_sha256_SHA256_sha256_impl(PyObject *self, PyObject *string)
+/*[clinic end generated code: checksum=c3c1d266f9e3196c16cad4bf2711fb78f5637f8a]*/
+{
     SHAobject *new;
-    PyObject *data_obj = NULL;
     Py_buffer buf;
 
-    if (!PyArg_ParseTupleAndKeywords(args, kwdict, "|O:new", kwlist,
-                                     &data_obj)) {
-        return NULL;
-    }
-
-    if (data_obj)
-        GET_BUFFER_VIEW_OR_ERROUT(data_obj, &buf);
+    if (string != Py_None)
+        GET_BUFFER_VIEW_OR_ERROUT(string, &buf);
 
     if ((new = newSHA256object()) == NULL) {
-        if (data_obj)
+        if (string != Py_None)
             PyBuffer_Release(&buf);
         return NULL;
     }
@@ -623,11 +670,11 @@
 
     if (PyErr_Occurred()) {
         Py_DECREF(new);
-        if (data_obj)
+        if (string != Py_None)
             PyBuffer_Release(&buf);
         return NULL;
     }
-    if (data_obj) {
+    if (string != Py_None) {
         sha_update(new, buf.buf, buf.len);
         PyBuffer_Release(&buf);
     }
@@ -635,27 +682,53 @@
     return (PyObject *)new;
 }
 
-PyDoc_STRVAR(SHA224_new__doc__,
+/*[clinic input]
+_sha256.SHA256.sha224
+
+    string: object = None
+
+Return a new SHA-224 hash object; optionally initialized with a string.
+[clinic start generated code]*/
+
+PyDoc_STRVAR(_sha256_SHA256_sha224__doc__,
+"sha224(string=None)\n"
 "Return a new SHA-224 hash object; optionally initialized with a string.");
 
+#define _SHA256_SHA256_SHA224_METHODDEF    \
+    {"sha224", (PyCFunction)_sha256_SHA256_sha224, METH_VARARGS|METH_KEYWORDS, _sha256_SHA256_sha224__doc__},
+
 static PyObject *
-SHA224_new(PyObject *self, PyObject *args, PyObject *kwdict)
+_sha256_SHA256_sha224_impl(PyObject *self, PyObject *string);
+
+static PyObject *
+_sha256_SHA256_sha224(PyObject *self, PyObject *args, PyObject *kwargs)
 {
-    static char *kwlist[] = {"string", NULL};
+    PyObject *return_value = NULL;
+    static char *_keywords[] = {"string", NULL};
+    PyObject *string = Py_None;
+
+    if (!PyArg_ParseTupleAndKeywords(args, kwargs,
+        "|O:sha224", _keywords,
+        &string))
+        goto exit;
+    return_value = _sha256_SHA256_sha224_impl(self, string);
+
+exit:
+    return return_value;
+}
+
+static PyObject *
+_sha256_SHA256_sha224_impl(PyObject *self, PyObject *string)
+/*[clinic end generated code: checksum=5954d185599991b04b593b6e0cec82cae05c2bad]*/
+{
     SHAobject *new;
-    PyObject *data_obj = NULL;
     Py_buffer buf;
 
-    if (!PyArg_ParseTupleAndKeywords(args, kwdict, "|O:new", kwlist,
-                                     &data_obj)) {
-        return NULL;
-    }
-
-    if (data_obj)
-        GET_BUFFER_VIEW_OR_ERROUT(data_obj, &buf);
+    if (string != Py_None)
+        GET_BUFFER_VIEW_OR_ERROUT(string, &buf);
 
     if ((new = newSHA224object()) == NULL) {
-        if (data_obj)
+        if (string != Py_None)
             PyBuffer_Release(&buf);
         return NULL;
     }
@@ -664,11 +737,11 @@
 
     if (PyErr_Occurred()) {
         Py_DECREF(new);
-        if (data_obj)
+        if (string != Py_None)
             PyBuffer_Release(&buf);
         return NULL;
     }
-    if (data_obj) {
+    if (string != Py_None) {
         sha_update(new, buf.buf, buf.len);
         PyBuffer_Release(&buf);
     }
@@ -680,8 +753,8 @@
 /* List of functions exported by this module */
 
 static struct PyMethodDef SHA_functions[] = {
-    {"sha256", (PyCFunction)SHA256_new, METH_VARARGS|METH_KEYWORDS, SHA256_new__doc__},
-    {"sha224", (PyCFunction)SHA224_new, METH_VARARGS|METH_KEYWORDS, SHA224_new__doc__},
+    _SHA256_SHA256_SHA256_METHODDEF
+    _SHA256_SHA256_SHA224_METHODDEF
     {NULL,      NULL}            /* Sentinel */
 };