Function Str_like_utf8_case_insensitive_find_iter

python/stringzilla.c:4760–4841

    "    [Str('Straße'), Str('STRASSE')]";

static PyObject *Str_like_utf8_case_insensitive_find_iter(PyObject *self, PyObject *const *args,
                                                          Py_ssize_t positional_args_count, PyObject *kwnames) {
    // Check if called as member or module function
    int is_member = self != NULL && PyObject_TypeCheck(self, &StrType);
    int min_args = is_member ? 1 : 2;
    int max_args = is_member ? 2 : 3;

    if (positional_args_count < min_args || positional_args_count > max_args) {
        PyErr_Format(PyExc_TypeError,
                     "utf8_case_insensitive_find_iter() requires %d to %d positional arguments, got %zd", min_args,
                     max_args, positional_args_count);
        return NULL;
    }

    PyObject *haystack_obj = is_member ? self : args[0];
    PyObject *needle_obj = is_member ? args[0] : args[1];
    int include_overlapping = 0;

    // Parse keyword arguments
    if (kwnames) {
        Py_ssize_t n_kwnames = PyTuple_GET_SIZE(kwnames);
        for (Py_ssize_t i = 0; i < n_kwnames; ++i) {
            PyObject *key = PyTuple_GET_ITEM(kwnames, i);
            PyObject *value = args[positional_args_count + i];
            if (PyUnicode_CompareWithASCIIString(key, "include_overlapping") == 0) {
                include_overlapping = PyObject_IsTrue(value);
            }
            else {
                PyErr_Format(PyExc_TypeError, "utf8_case_insensitive_find_iter() got unexpected keyword argument '%U'",
                             key);
                return NULL;
            }
        }
    }

    // Check positional include_overlapping argument
    if (positional_args_count > max_args - 1) include_overlapping = PyObject_IsTrue(args[is_member ? 1 : 2]);

    // Extract haystack and needle views
    sz_string_view_t haystack_view, needle_view;
    if (!sz_py_export_string_like(haystack_obj, &haystack_view.start, &haystack_view.length) ||
        !sz_py_export_string_like(needle_obj, &needle_view.start, &needle_view.length)) {
        return NULL; // Exception already set by helper
    }

    // Handle edge case: empty needle yields nothing
    if (needle_view.length == 0) {
        // Return an empty iterator by setting current = end
        Utf8CaseInsensitiveFindIterator *iter =
            PyObject_New(Utf8CaseInsensitiveFindIterator, &Utf8CaseInsensitiveFindIteratorType);
        if (!iter) return PyErr_NoMemory();

        iter->haystack_obj = haystack_obj;
        Py_INCREF(haystack_obj);
        iter->needle_obj = needle_obj;
        Py_INCREF(needle_obj);
        iter->current = haystack_view.start + haystack_view.length; // Start at end = empty iterator
        iter->haystack_end = haystack_view.start + haystack_view.length;