You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: utils.rs
    path of file: ./repos/nvim-oxi/crates/luajit/src
    
    the code of the file until where you have to start completion: use std::ffi::{c_int, CStr};
use std::fmt::Display;

use crate::ffi::{self, lua_State};

/// Does nothing if the stack is already taller than `n`, grows the stack
/// height to `n` by adding `nil`s if it's not.
pub unsafe fn grow_stack(lstate: *mut lua_State, n: c_int) {
    if ffi::lua_gettop(lstate) < n {
        ffi::lua_setto
    
pub unsafe fn is_table_array(lstate: *mut lua_State, index: c_int) -> bool {
    ffi::lua_pushnil(lstate);

    if ffi::lua_next(lstate, index - 1) == 0 {
        // Empty table.
        if ffi::lua_getmetatable(lstate, index) == 0 {
            return true;
        }
        ffi::lua_pop(lstate, 1);
        return false;
    }

    let ty = ffi::lua_type(lstate, -2);
    ffi::lua_pop(lstate, 2);
    ty == ffi::LUA_TNUMBER
}