Optimize bytearray % args

Issue #25399: Don't create temporary bytes objects: modify _PyBytes_Format() to
create work directly on bytearray objects.

* Rename _PyBytes_Format() to _PyBytes_FormatEx() just in case if something
  outside CPython uses it
* _PyBytes_FormatEx() now uses (char*, Py_ssize_t) for the input string, so
  bytearray_format() doesn't need tot create a temporary input bytes object
* Add use_bytearray parameter to _PyBytes_FormatEx() which is passed to
  _PyBytesWriter, to create a bytearray buffer instead of a bytes buffer

Most formatting operations are now between 2.5 and 5 times faster.

1 files changed, 5 insertions, 17 deletions

diff --git a/Objects/bytearrayobject.c b/Objects/bytearrayobject.c
index 5647b57a52..e535bce8d7 100644
--- a/Objects/bytearrayobject.c
+++ b/Objects/bytearrayobject.c
@@ -282,26 +282,14 @@ PyByteArray_Concat(PyObject *a, PyObject *b)
 static PyObject *
 bytearray_format(PyByteArrayObject *self, PyObject *args)
 {
-    PyObject *bytes_in, *bytes_out, *res;
-    char *bytestring;
-
-    if (self == NULL || !PyByteArray_Check(self) || args == NULL) {
+    if (self == NULL || !PyByteArray_Check(self)) {
         PyErr_BadInternalCall();
         return NULL;
     }
-    bytestring = PyByteArray_AS_STRING(self);
-    bytes_in = PyBytes_FromString(bytestring);
-    if (bytes_in == NULL)
-        return NULL;
-    bytes_out = _PyBytes_Format(bytes_in, args);
-    Py_DECREF(bytes_in);
-    if (bytes_out == NULL)
-        return NULL;
-    res = PyByteArray_FromObject(bytes_out);
-    Py_DECREF(bytes_out);
-    if (res == NULL)
-        return NULL;
-    return res;
+
+    return _PyBytes_FormatEx(PyByteArray_AS_STRING(self),
+                             PyByteArray_GET_SIZE(self),
+                             args, 1);
 }
 
 /* Functions stuffed into the type object */