replace_delete_substring(PyBytesObject *self,
                         const char *from_s, Py_ssize_t from_len,
                         Py_ssize_t maxcount) {
    char *self_s, *result_s;
    char *start, *next, *end;
    Py_ssize_t self_len, result_len;
    Py_ssize_t count, offset;
    PyBytesObject *result;

    self_len = PyBytes_GET_SIZE(self);
    self_s = PyBytes_AS_STRING(self);

    count = stringlib_count(self_s, self_len,
                            from_s, from_len,
                            maxcount);

    if (count == 0) {
        /* no matches */
        return return_self(self);
    }

    result_len = self_len - (count * from_len);
    assert (result_len>=0);

    if ( (result = (PyBytesObject *)
          PyBytes_FromStringAndSize(NULL, result_len)) == NULL )
        return NULL;

    result_s = PyBytes_AS_STRING(result);

    start = self_s;
    end = self_s + self_len;
    while (count-- > 0) {
        offset = stringlib_find(start, end-start,
                                from_s, from_len,
                                0);
        if (offset == -1)
            break;
        next = start + offset;

        Py_MEMCPY(result_s, start, next-start);

        result_s += (next-start);
        start = next+from_len;
    }
    Py_MEMCPY(result_s, start, end-start);
    return result;
}
Unknown