Function sz_py_is_mutable

python/stringzilla.c:420–438

* @brief Helper function to check if a Python object represents a mutable buffer. * Returns sz_true_k if the object is mutable (can be written to), sz_false_k if immutable. * Sets a Python exception if immutable. */

 *          Sets a Python exception if immutable.
 */
SZ_INTERNAL sz_bool_t sz_py_is_mutable(PyObject *object) {
    if (PyUnicode_Check(object)) {
        PyErr_SetString(PyExc_TypeError, "str objects are immutable (use bytearray instead)");
        return sz_false_k;
    }
    else if (PyBytes_Check(object)) {
        PyErr_SetString(PyExc_TypeError, "bytes objects are immutable (use bytearray instead)");
        return sz_false_k;
    }
    else if (PyMemoryView_Check(object)) {
        Py_buffer *view = PyMemoryView_GET_BUFFER(object);
        if (view->readonly) {
            PyErr_SetString(PyExc_TypeError, "memoryview is read-only");
            return sz_false_k;
        }
    }
    // Everything else is optimistically considered mutable
    return sz_true_k;
}

/**
 *  @brief  Helper function to export a Python string-like object into a `sz_string_view_t`.