adapted __Pyx_PyObject_AsPy_UNICODE() to PEP 393

Cython/Compiler/PyrexTypes.py

@@ -1053,20 +1053,31 @@ static CYTHON_INLINE Py_UNICODE __Pyx_PyObject_AsPy_UNICODE(PyObject*);
 ''',
 impl='''
 static CYTHON_INLINE Py_UNICODE __Pyx_PyObject_AsPy_UNICODE(PyObject* x) {
-   static long maxval = 0;
     long ival;
+    #ifdef CYTHON_PEP393_ENABLED
+    const long maxval = 1114111;
+    #else
+    static long maxval = 0;
+    #endif
     if (PyUnicode_Check(x)) {
-       if (unlikely(PyUnicode_GET_SIZE(x) != 1)) {
+        if (unlikely(__Pyx_PyUnicode_GET_LENGTH(x) != 1)) {
             PyErr_Format(PyExc_ValueError,
                          "only single character unicode strings can be converted to Py_UNICODE, "
-                        "got length %"PY_FORMAT_SIZE_T"d", PyUnicode_GET_SIZE(x));
+                         "got length %"PY_FORMAT_SIZE_T"d", __Pyx_PyUnicode_GET_LENGTH(x));
             return (Py_UNICODE)-1;
         }
+        #ifdef CYTHON_PEP393_ENABLED
+        ival = PyUnicode_READ_CHAR(x, 0);
+        #else
         return PyUnicode_AS_UNICODE(x)[0];
-   }
+        #endif
+    } else {
+        #ifndef CYTHON_PEP393_ENABLED
         if (unlikely(!maxval))
             maxval = (long)PyUnicode_GetMax();
+        #endif
         ival = __Pyx_PyInt_AsLong(x);
+    }
     if (unlikely(ival < 0)) {
         if (!PyErr_Occurred())
             PyErr_SetString(PyExc_OverflowError,