Add an optional size argument to _Py_char2wchar()

_Py_char2wchar() callers usually need the result size in characters. Since it's
trivial to compute it in _Py_char2wchar() (O(1) whereas wcslen() is O(n)), add
an option to get it.

1 files changed, 3 insertions, 2 deletions

diff --git a/Objects/unicodeobject.c b/Objects/unicodeobject.c
index 98427e3c2c..9fe9c42796 100644
--- a/Objects/unicodeobject.c
+++ b/Objects/unicodeobject.c
@@ -1783,17 +1783,18 @@ PyUnicode_DecodeFSDefaultAndSize(const char *s, Py_ssize_t size)
         /* locale encoding with surrogateescape */
         wchar_t *wchar;
         PyObject *unicode;
+        size_t len;
 
         if (s[size] != '\0' || size != strlen(s)) {
             PyErr_SetString(PyExc_TypeError, "embedded NUL character");
             return NULL;
         }
 
-        wchar = _Py_char2wchar(s);
+        wchar = _Py_char2wchar(s, &len);
         if (wchar == NULL)
             return NULL;
 
-        unicode = PyUnicode_FromWideChar(wchar, -1);
+        unicode = PyUnicode_FromWideChar(wchar, len);
         PyMem_Free(wchar);
         return unicode;
     }