Function Str_init

python/stringzilla.c:1137–1199

#pragma region Str

static int Str_init(Str *self, PyObject *args, PyObject *kwargs) {

    // Parse all arguments into PyObjects first
    Py_ssize_t nargs = PyTuple_Size(args);
    if (nargs > 3) {
        PyErr_SetString(PyExc_TypeError, "Invalid number of arguments");
        return -1;
    }
    PyObject *parent_obj = nargs >= 1 ? PyTuple_GET_ITEM(args, 0) : NULL;
    PyObject *from_obj = nargs >= 2 ? PyTuple_GET_ITEM(args, 1) : NULL;
    PyObject *to_obj = nargs >= 3 ? PyTuple_GET_ITEM(args, 2) : NULL;

    // Parse keyword arguments, if provided, and ensure no duplicates
    if (kwargs) {
        Py_ssize_t pos = 0;
        PyObject *key, *value;
        while (PyDict_Next(kwargs, &pos, &key, &value))
            if (PyUnicode_CompareWithASCIIString(key, "parent") == 0 && !parent_obj) { parent_obj = value; }
            else if (PyUnicode_CompareWithASCIIString(key, "from") == 0 && !from_obj) { from_obj = value; }
            else if (PyUnicode_CompareWithASCIIString(key, "to") == 0 && !to_obj) { to_obj = value; }
            else if (PyErr_Format(PyExc_TypeError, "Got an unexpected keyword argument '%U'", key))
                return -1;
    }

    // Now, layout-check and cast each argument
    Py_ssize_t from = 0, to = PY_SSIZE_T_MAX;
    if (from_obj) {
        from = PyLong_AsSsize_t(from_obj);
        if (from == -1 && PyErr_Occurred()) {
            PyErr_SetString(PyExc_TypeError, "The `from` argument must be an integer");
            return -1;
        }
    }
    if (to_obj) {
        to = PyLong_AsSsize_t(to_obj);
        if (to == -1 && PyErr_Occurred()) {
            PyErr_SetString(PyExc_TypeError, "The `to` argument must be an integer");
            return -1;
        }
    }

    // Handle empty string
    if (parent_obj == NULL) {
        self->memory.start = NULL;
        self->memory.length = 0;
    }
    // Increment the reference count of the parent
    else if (sz_py_export_string_like(parent_obj, &self->memory.start, &self->memory.length)) {
        self->parent = parent_obj;
        Py_INCREF(parent_obj);
    }
    else {
        wrap_current_exception("Unsupported parent type");
        return -1;
    }

    // Apply slicing
    sz_size_t normalized_offset, normalized_length;