luau_vm/table/

mod.rs

use core::mem;
use core::ptr::{self, NonNull};

mod layout;
mod lookup;

pub use layout::{
    LuaNode, LuaNodeCursor, RAW_LUA_NODE_DUMMY, RAW_TKEY_DEAD_KEY, RAW_TKEY_NIL, RawLuaNode,
    RawTKey, TKey,
};

use crate::VmErrorResult;
use crate::debug::DebugRuntime;
use crate::gc::GcBarrier;
use crate::gc::{GcObject, RawGcObject};
use crate::handle::RawHandle;
use crate::handle::sealed::Sealed;
use crate::memory::{LuaPage, MemoryRuntime};
use crate::string::TString;
use crate::thread::Thread;
use crate::types::{LUA_TNUMBER, LUA_TTABLE};
use crate::value::{RAW_TVALUE_NIL, RawTValue, TValue, TValueCursor, nil_object};

#[repr(C)]
pub struct RawLuaTable {
    pub tt: u8,
    pub marked: u8,
    pub memcat: u8,
    pub tm_cache: u8,
    pub readonly: u8,
    pub safe_env: u8,
    pub lsize_node: u8,
    pub node_mask_8: u8,
    pub size_array: i32,
    pub free: RawLuaTableFree,
    pub metatable: *mut RawLuaTable,
    pub array: *mut RawTValue,
    pub node: *mut RawLuaNode,
    pub gc_list: *mut RawGcObject,
}

#[repr(C)]
pub union RawLuaTableFree {
    pub last_free: i32,
    pub aboundary: i32,
}

const LOG_2: [u8; 256] = [
    0, 1, 2, 2, 3, 3, 3, 3, 4, 4, 4, 4, 4, 4, 4, 4, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5,
    6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6,
    7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7,
    7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7,
    8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8,
    8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8,
    8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8,
    8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8,
];

/// `luaO_log2`
fn log_2(mut value: u32) -> i32 {
    let mut log = -1;
    while value >= 256 {
        log += 8;
        value >>= 8;
    }
    log + i32::from(LOG_2[value as usize])
}

/// `ceillog2`
pub(super) fn ceil_log_2(value: u32) -> i32 {
    log_2(value - 1) + 1
}

#[derive(Clone, Copy, PartialEq, Eq)]
#[repr(transparent)]
/// Non-owning identity of a VM table record.
///
/// # Safety model for unsafe methods
///
/// The table and referenced storage must remain live in its owning VM. Keys,
/// values, nodes, and indices must match the current allocation; resize or
/// free operations invalidate derived cursors and views. Mutation must
/// preserve hashing, readonly, metatable-cache, and GC barrier invariants.
pub struct Table {
    pub(crate) raw: NonNull<RawLuaTable>,
}

/// Unstable table allocation and mutation capability.
///
/// # Safety
///
/// Tables, keys, values, cursors, and pages must be live records from this
/// thread's VM. Stack cursors and storage indices must be in bounds, and all
/// resize, hash, readonly, metatable, and GC barrier invariants must hold.
#[allow(
    clippy::missing_safety_doc,
    reason = "all methods share the capability-level safety contract"
)]
pub trait TableRuntime: Sealed {
    unsafe fn set_num(&self, table: Table, key: i32) -> VmErrorResult<TValue>;
    unsafe fn set_str(&self, table: Table, key: TString) -> VmErrorResult<LuaNodeCursor>;
    unsafe fn setp(&self, table: Table, key: *mut (), tag: i32) -> VmErrorResult<TValue>;
    unsafe fn set(&self, table: Table, key: TValue) -> VmErrorResult<TValue>;
    unsafe fn set_slot(&self, table: Table, slot: TValue, key: TValue) -> VmErrorResult<TValue>;
    unsafe fn new_key(&self, table: Table, key: TValue) -> VmErrorResult<TValue>;
    unsafe fn next_internal(&self, table: Table, key: TValueCursor) -> VmErrorResult<i32>;
    unsafe fn new_table_internal(&self, n_array: i32, n_hash: i32) -> VmErrorResult<Table>;
    unsafe fn resize_array(&self, table: Table, n_array: i32) -> VmErrorResult;
    unsafe fn resize_hash(&self, table: Table, n_hash: i32) -> VmErrorResult;
    unsafe fn free_table(&self, table: Table, page: LuaPage);
    unsafe fn clone_table_internal(&self, table: Table) -> VmErrorResult<Table>;
}

impl crate::handle::sealed::Sealed for Table {}

impl RawHandle for Table {
    type Raw = RawLuaTable;

    fn as_ptr(&self) -> *mut Self::Raw {
        self.raw.as_ptr()
    }
}

impl AsRef<Table> for Table {
    fn as_ref(&self) -> &Table {
        self
    }
}

const MAX_BITS: i32 = 26;
const MAX_SIZE: i32 = 1 << MAX_BITS;

/// `twoto`
fn twoto(value: i32) -> i32 {
    1 << value
}

/// `countint`
fn count_int(key: f64, nums: &mut [i32; (MAX_BITS + 1) as usize]) -> i32 {
    match Table::array_index(key) {
        Some(index) if index > 0 && index <= MAX_SIZE => {
            nums[ceil_log_2(index as u32) as usize] += 1;
            1
        }
        _ => 0,
    }
}

/// `computesizes`
fn compute_sizes(nums: &[i32; (MAX_BITS + 1) as usize], n_array: &mut i32) -> i32 {
    let mut a = 0;
    let mut na = 0;
    let mut n = 0;
    let mut twotoi = 1;
    let mut index = 0;

    while twotoi / 2 < *n_array {
        if nums[index] > 0 {
            a += nums[index];
            if a > twotoi / 2 {
                n = twotoi;
                na = a;
            }
        }

        if a == *n_array {
            break;
        }

        index += 1;
        twotoi *= 2;
    }

    *n_array = n;
    debug_assert!(*n_array / 2 <= na && na <= *n_array);
    na
}

#[allow(
    clippy::missing_safety_doc,
    reason = "Table's shared raw-handle contract is documented on Table"
)]
impl Table {
    /// `numusearray`
    fn num_use_array(&self, nums: &mut [i32; (MAX_BITS + 1) as usize]) -> i32 {
        let mut ause = 0;
        let mut index = 1;
        let mut ttlg = 1;
        let size_array = unsafe { self.as_ptr().as_ref().unwrap_unchecked().size_array };
        let array = unsafe { self.array_cursor() };

        for lg in 0..=MAX_BITS {
            let mut lc = 0;
            let mut limit = ttlg;
            if limit > size_array {
                limit = size_array;
                if index > limit {
                    break;
                }
            }

            while index <= limit {
                if unsafe { !array.add((index - 1) as usize).is_nil_unchecked() } {
                    lc += 1;
                }
                index += 1;
            }

            nums[lg as usize] += lc;
            ause += lc;
            ttlg *= 2;
        }

        ause
    }

    /// `numusehash`
    fn num_use_hash(&self, nums: &mut [i32; (MAX_BITS + 1) as usize], n_array: &mut i32) -> i32 {
        let mut total_use = 0;
        let mut ause = 0;
        let mut index = unsafe { self.node_count() };

        while index > 0 {
            index -= 1;
            let node = unsafe { self.node(index as i32) };
            if !node.value_unchecked().is_nil() {
                let key = node.key();
                if key.tt() == LUA_TNUMBER {
                    ause += count_int(key.number_value(), nums);
                }
                total_use += 1;
            }
        }

        *n_array += ause;
        total_use
    }

    /// `setarrayvector`
    unsafe fn set_array_vector(&self, thread: &Thread, size: i32) -> VmErrorResult {
        if size > MAX_SIZE {
            return unsafe { crate::run_error!(thread, "table overflow") };
        }

        unsafe {
            let old_size = self.as_ptr().as_ref().unwrap_unchecked().size_array as usize;
            let new_size = size as usize;
            let memcat = self.as_ptr().as_ref().unwrap_unchecked().memcat;
            let array = TValueCursor::from_ptr(thread.realloc_array(
                self.as_ptr().as_ref().unwrap_unchecked().array,
                old_size,
                new_size,
                memcat,
            )?);

            for index in old_size..new_size {
                array.add(index).value_unchecked().set_nil();
            }
            self.set_array(array);
            self.as_ptr().as_mut().unwrap_unchecked().size_array = size;
        }
        Ok(())
    }

    /// `setnodevector`
    unsafe fn set_node_vector(&self, thread: &Thread, size: i32) -> VmErrorResult {
        unsafe {
            let (node, lsize, count) = if size == 0 {
                (Table::dummy_node_cursor(), 0, 0usize)
            } else {
                let lsize = ceil_log_2(size as u32);
                if lsize > MAX_BITS {
                    return crate::run_error!(thread, "table overflow");
                }

                let count = twoto(lsize) as usize;
                let node = LuaNodeCursor::from_ptr(thread.new_array::<RawLuaNode>(
                    count,
                    self.as_ptr().as_ref().unwrap_unchecked().memcat,
                )?);

                for index in 0..count {
                    let current_cursor = node.add(index);
                    let current_node = current_cursor.node_unchecked();
                    current_node.key().set_nil();
                    current_node.value_unchecked().set_nil();
                }

                (node, lsize, count)
            };

            self.set_node(node);
            self.as_ptr().as_mut().unwrap_unchecked().lsize_node = lsize as u8;
            self.as_ptr().as_mut().unwrap_unchecked().node_mask_8 = ((1 << lsize) - 1) as u8;
            self.as_ptr().as_mut().unwrap_unchecked().free = RawLuaTableFree {
                last_free: count as i32,
            };
        }
        Ok(())
    }

    /// `arrayornewkey`
    unsafe fn array_or_new_key(&self, thread: &Thread, key: TValue) -> VmErrorResult<TValue> {
        unsafe {
            if key.is_number() {
                let Some(index) = Table::array_index(key.number_value()) else {
                    return self.new_key(thread, key);
                };
                if let Some(slot) = self.array_slot_for_key(index) {
                    return Ok(slot);
                }
            }

            self.new_key(thread, key)
        }
    }

    /// `resize`
    unsafe fn resize(&self, thread: &Thread, n_array: i32, n_hash: i32) -> VmErrorResult {
        unsafe {
            if n_array > MAX_SIZE || n_hash > MAX_SIZE {
                return crate::run_error!(thread, "table overflow");
            }

            let old_array_size = self.as_ptr().as_ref().unwrap_unchecked().size_array;
            let old_hash_lsize = self.as_ptr().as_ref().unwrap_unchecked().lsize_node as i32;
            let old_nodes = self.node_cursor();

            if n_array > old_array_size {
                self.set_array_vector(thread, n_array)?;
            }

            self.set_node_vector(thread, n_hash)?;
            let new_nodes = self.node_cursor();

            if n_array < old_array_size {
                self.as_ptr().as_mut().unwrap_unchecked().size_array = n_array;

                for index in n_array..old_array_size {
                    let value = self.array_slot(index as usize);
                    if !value.is_nil() {
                        let mut key_storage = RawTValue::number((index + 1) as f64);
                        let key = TValue::from_mut(&mut key_storage);
                        self.array_or_new_key(thread, key)?.set_obj(value);
                    }
                }

                let array = TValueCursor::from_ptr(thread.realloc_array(
                    self.as_ptr().as_ref().unwrap_unchecked().array,
                    old_array_size as usize,
                    n_array as usize,
                    self.as_ptr().as_ref().unwrap_unchecked().memcat,
                )?);
                self.set_array(array);
            }

            let new_array = self.array_cursor();
            for index in (0..twoto(old_hash_lsize)).rev() {
                let old_cursor = old_nodes.add(index as usize);
                let old_node = old_cursor.node_unchecked();
                if !old_node.value_unchecked().is_nil() {
                    let mut key_storage = RawTValue::nil();
                    let key = TValue::from_mut(&mut key_storage);
                    old_node.write_key_to_value(key);
                    self.array_or_new_key(thread, key)?
                        .set_obj(old_node.value_unchecked());
                }
            }

            debug_assert!(new_nodes == self.node_cursor());
            debug_assert!(new_array == self.array_cursor());

            if old_nodes != Table::dummy_node_cursor() {
                thread.free_array(
                    old_nodes.as_ptr(),
                    twoto(old_hash_lsize) as usize,
                    self.as_ptr().as_ref().unwrap_unchecked().memcat,
                );
            }
        }
        Ok(())
    }

    /// `adjustasize`
    unsafe fn adjust_array_size(&self, mut size: i32, extra_key: Option<TValue>) -> i32 {
        let table_bound = unsafe {
            !self.has_dummy_node() || size < self.as_ptr().as_ref().unwrap_unchecked().size_array
        };
        let extra_key_index = extra_key
            .and_then(|key| {
                if key.is_number() {
                    Table::array_index(key.number_value())
                } else {
                    None
                }
            })
            .unwrap_or(-1);

        while size + 1 == extra_key_index
            || (table_bound && !unsafe { self.get_num(size + 1) }.is_nil())
        {
            size += 1;
        }

        size
    }

    /// `rehash`
    unsafe fn rehash(&self, thread: &Thread, extra_key: TValue) -> VmErrorResult {
        let mut nums = [0; (MAX_BITS + 1) as usize];
        let mut n_array = self.num_use_array(&mut nums);
        let mut total_use = n_array;
        total_use += self.num_use_hash(&mut nums, &mut n_array);

        if extra_key.is_number() {
            n_array += count_int(extra_key.number_value(), &mut nums);
        }
        total_use += 1;

        let na = compute_sizes(&nums, &mut n_array);
        let mut n_hash = total_use - na;

        unsafe {
            let mut adjusted = self.adjust_array_size(n_array, Some(extra_key));
            let extra_array = adjusted - n_array;
            if extra_array != 0 {
                n_hash -= extra_array;
                n_array = adjusted + extra_array;
                adjusted = self.adjust_array_size(n_array, Some(extra_key));
            }

            self.resize(thread, adjusted, n_hash)?;
        }
        Ok(())
    }

    /// `getfreepos`
    unsafe fn free_position(&self) -> Option<LuaNodeCursor> {
        let mut last_free = unsafe { self.as_ptr().as_ref().unwrap_unchecked().free.last_free };
        while last_free > 0 {
            last_free -= 1;
            unsafe {
                self.as_ptr().as_mut().unwrap_unchecked().free = RawLuaTableFree { last_free };
                let node_cursor = self.node_cursor().add(last_free as usize);
                if node_cursor.node_unchecked().key().is_nil() {
                    return Some(node_cursor);
                }
            }
        }

        None
    }

    unsafe fn new_hash_key(&self, thread: &Thread, key: TValue) -> VmErrorResult<TValue> {
        unsafe {
            let mut main_cursor = self.main_position(key);
            if !main_cursor.node_unchecked().value_unchecked().is_nil()
                || main_cursor == Table::dummy_node_cursor()
            {
                let Some(free_cursor) = self.free_position() else {
                    self.rehash(thread, key)?;
                    return self.array_or_new_key(thread, key);
                };

                debug_assert!(free_cursor != Table::dummy_node_cursor());

                let mut main_key_storage = RAW_TVALUE_NIL;
                let main_key = TValue::from_mut(&mut main_key_storage);
                main_cursor.node_unchecked().write_key_to_value(main_key);

                let mut other_cursor = self.main_position(main_key);
                if other_cursor != main_cursor {
                    let mut next_cursor =
                        other_cursor.offset(other_cursor.node_unchecked().next() as isize);
                    while next_cursor != main_cursor {
                        other_cursor =
                            other_cursor.offset(other_cursor.node_unchecked().next() as isize);
                        next_cursor =
                            other_cursor.offset(other_cursor.node_unchecked().next() as isize);
                    }

                    other_cursor
                        .node_unchecked()
                        .key()
                        .set_next(free_cursor.offset_from(other_cursor) as i32);
                    ptr::copy_nonoverlapping(main_cursor.as_ptr(), free_cursor.as_ptr(), 1);
                    let main_next = main_cursor.node_unchecked().next();
                    if main_next != 0 {
                        free_cursor.node_unchecked().key().set_next(
                            free_cursor.node_unchecked().next()
                                + main_cursor.offset_from(free_cursor) as i32,
                        );
                        main_cursor.node_unchecked().key().set_next(0);
                    }
                    main_cursor.node_unchecked().value_unchecked().set_nil();
                } else {
                    let main_next = main_cursor.node_unchecked().next();
                    if main_next != 0 {
                        free_cursor.node_unchecked().key().set_next(
                            main_cursor
                                .offset(main_next as isize)
                                .offset_from(free_cursor) as i32,
                        );
                    } else {
                        debug_assert!(free_cursor.node_unchecked().next() == 0);
                    }

                    main_cursor
                        .node_unchecked()
                        .key()
                        .set_next(free_cursor.offset_from(main_cursor) as i32);
                    main_cursor = free_cursor;
                }
            }

            let main_node = main_cursor.node_unchecked();
            main_node.set_key_from_value(key);
            if key.is_collectable() {
                let object = key.gc_value();
                let table_object: GcObject = (*self).into();
                if table_object.is_black() && object.is_white() {
                    thread.barrier_table(*self, object);
                }
            }

            debug_assert!(main_node.value_unchecked().is_nil());
            Ok(main_node.value())
        }
    }

    /// `newkey`
    unsafe fn new_key(&self, thread: &Thread, key: TValue) -> VmErrorResult<TValue> {
        unsafe {
            let size_array = self.as_ptr().as_ref().unwrap_unchecked().size_array;
            if key.is_number() && key.number_value() == (size_array + 1) as f64 {
                self.rehash(thread, key)?;
                return self.array_or_new_key(thread, key);
            }

            self.new_hash_key(thread, key)
        }
    }

    /// `findindex`
    unsafe fn find_index(&self, thread: &Thread, key: TValue) -> VmErrorResult<i32> {
        if key.is_nil() {
            return Ok(-1);
        }

        unsafe {
            if key.is_number()
                && matches!(
                    Table::array_index(key.number_value()),
                    Some(index) if index > 0 && index <= self.as_ptr().as_ref().unwrap_unchecked().size_array
                )
            {
                return Ok(Table::array_index(key.number_value()).unwrap_unchecked() - 1);
            }

            let mut node_cursor = self.main_position(key);
            loop {
                let node_key = node_cursor.node_unchecked().key();
                if node_key.raw_equal_value(key)
                    || (node_key.is_dead_key()
                        && key.is_collectable()
                        && node_key.gc_value() == key.gc_value())
                {
                    let index = self.node_index(node_cursor);
                    return Ok(index + self.as_ptr().as_ref().unwrap_unchecked().size_array);
                }

                let next = node_key.next();
                if next == 0 {
                    break;
                }
                node_cursor = node_cursor.offset(next as isize);
            }

            crate::run_error!(thread, "invalid key to 'next'")
        }
    }
}

impl TableRuntime for Thread {
    /// `luaH_setnum`
    #[inline(always)]
    unsafe fn set_num(&self, table: Table, key: i32) -> VmErrorResult<TValue> {
        unsafe {
            if let Some(slot) = table.array_slot_for_key(key) {
                Ok(slot)
            } else {
                let slot = table.get_num(key);
                if slot != nil_object() {
                    Ok(slot)
                } else {
                    let mut value_storage = RawTValue::number(key as f64);
                    let value = TValue::from_mut(&mut value_storage);
                    table.new_key(self, value)
                }
            }
        }
    }

    /// `luaH_setstr`
    #[inline(always)]
    unsafe fn set_str(&self, table: Table, key: TString) -> VmErrorResult<LuaNodeCursor> {
        unsafe {
            table.invalidate_tm_cache();

            if let Some(node_cursor) = table.get_str_node(key) {
                Ok(node_cursor)
            } else {
                let mut value_storage = RawTValue::string(key);
                let value = TValue::from_mut(&mut value_storage);
                table.new_hash_key(self, value)?;
                Ok(table.get_str_node(key).unwrap_unchecked())
            }
        }
    }

    /// `luaH_setp`
    unsafe fn setp(&self, table: Table, key: *mut (), tag: i32) -> VmErrorResult<TValue> {
        unsafe {
            let slot = table.getp(key, tag);
            if slot != nil_object() {
                Ok(slot)
            } else {
                let mut value_storage = RawTValue::light_userdata(key, tag);
                let value = TValue::from_mut(&mut value_storage);
                table.new_key(self, value)
            }
        }
    }

    /// `luaH_set`
    unsafe fn set(&self, table: Table, key: TValue) -> VmErrorResult<TValue> {
        unsafe {
            let slot = table.get(key);
            self.set_slot(table, slot, key)
        }
    }

    /// `luaH_setslot`
    unsafe fn set_slot(&self, table: Table, slot: TValue, key: TValue) -> VmErrorResult<TValue> {
        unsafe {
            table.invalidate_tm_cache();
            if slot != nil_object() {
                Ok(slot)
            } else {
                self.new_key(table, key)
            }
        }
    }

    /// `luaH_newkey`
    unsafe fn new_key(&self, table: Table, key: TValue) -> VmErrorResult<TValue> {
        unsafe {
            if key.is_nil() {
                return crate::run_error!(self, "table index is nil");
            } else if key.is_number() && key.number_value().is_nan() {
                return crate::run_error!(self, "table index is NaN");
            } else if key.is_vector() && crate::number::vec_is_nan(&key.vector_value()) {
                return crate::run_error!(self, "table index contains NaN");
            }

            table.new_key(self, key)
        }
    }

    /// `luaH_next`
    unsafe fn next_internal(&self, table: Table, key: TValueCursor) -> VmErrorResult<i32> {
        unsafe {
            let mut index = table.find_index(self, key.value_unchecked())?;

            index += 1;
            while index < table.as_ptr().as_ref().unwrap_unchecked().size_array {
                let value = table.array_slot(index as usize);
                if !value.is_nil() {
                    key.value_unchecked().set_number((index + 1) as f64);
                    key.add(1).value_unchecked().set_obj(value);
                    return Ok(1);
                }
                index += 1;
            }

            index -= table.as_ptr().as_ref().unwrap_unchecked().size_array;
            while index < table.node_count() as i32 {
                let node = table.node(index);
                if !node.value_unchecked().is_nil() {
                    node.write_key_to_value(key.value_unchecked());
                    key.add(1).value_unchecked().set_obj(node.value_unchecked());
                    return Ok(1);
                }
                index += 1;
            }

            Ok(0)
        }
    }

    /// `luaH_new`
    unsafe fn new_table_internal(&self, n_array: i32, n_hash: i32) -> VmErrorResult<Table> {
        let table = unsafe {
            let table = self.new_gco::<Table>(
                mem::size_of::<RawLuaTable>(),
                self.as_ptr().as_ref().unwrap_unchecked().active_memcat,
            )?;
            GcObject::from(table).init_header(self, LUA_TTABLE as u8);
            let table_ref = table.as_ptr().as_mut().unwrap_unchecked();
            table_ref.metatable = ptr::null_mut();
            table_ref.tm_cache = !0;
            table.init_empty_storage();
            if n_array > 0 {
                table.set_array_vector(self, n_array)?;
            }
            if n_hash > 0 {
                table.set_node_vector(self, n_hash)?;
            }
            table
        };

        Ok(table)
    }

    /// `luaH_resizearray`
    unsafe fn resize_array(&self, table: Table, n_array: i32) -> VmErrorResult {
        unsafe {
            let n_hash = if table.has_dummy_node() {
                0
            } else {
                table.node_count() as i32
            };
            let adjusted = table.adjust_array_size(n_array, None);
            table.resize(self, adjusted, n_hash)
        }
    }

    /// `luaH_resizehash`
    unsafe fn resize_hash(&self, table: Table, n_hash: i32) -> VmErrorResult {
        unsafe {
            table.resize(
                self,
                table.as_ptr().as_ref().unwrap_unchecked().size_array,
                n_hash,
            )
        }
    }

    /// `luaH_free`
    unsafe fn free_table(&self, table: Table, page: LuaPage) {
        unsafe {
            let table_ref = table.as_ptr().as_ref().unwrap_unchecked();
            let memcat = table_ref.memcat;
            table.free_storage(self);
            self.free_gco(
                table.into(),
                core::mem::size_of::<RawLuaTable>(),
                memcat,
                page,
            );
        }
    }

    /// `luaH_clone`
    unsafe fn clone_table_internal(&self, table: Table) -> VmErrorResult<Table> {
        unsafe {
            let active_memcat = self.as_ptr().as_ref().unwrap_unchecked().active_memcat;
            let cloned = self.new_gco::<Table>(mem::size_of::<RawLuaTable>(), active_memcat)?;
            GcObject::from(cloned).init_header(self, LUA_TTABLE as u8);

            let cloned_ref = cloned.as_ptr().as_mut().unwrap_unchecked();
            cloned_ref.metatable = table
                .metatable()
                .map_or(ptr::null_mut(), |table| table.as_ptr());
            cloned_ref.tm_cache = table.as_ptr().as_ref().unwrap_unchecked().tm_cache;
            cloned.init_empty_storage();

            let table_ref = table.as_ptr().as_ref().unwrap_unchecked();
            let cloned_memcat = cloned.as_ptr().as_ref().unwrap_unchecked().memcat;

            if table_ref.size_array > 0 {
                let size_array = table_ref.size_array as usize;
                let array =
                    TValueCursor::from_ptr(self.new_array::<RawTValue>(size_array, cloned_memcat)?);

                cloned.set_array(array);
                cloned.as_ptr().as_mut().unwrap_unchecked().size_array = table_ref.size_array;
                cloned.maybe_set_aboundary(table.get_aboundary());
                ptr::copy_nonoverlapping(table.array_cursor().as_ptr(), array.as_ptr(), size_array);
            }

            if !table.has_dummy_node() {
                let size = table.node_count();
                let node = self.new_array::<RawLuaNode>(size, cloned_memcat)?;

                cloned.set_node(LuaNodeCursor::from_ptr(node));
                cloned.as_ptr().as_mut().unwrap_unchecked().lsize_node = table_ref.lsize_node;
                cloned.as_ptr().as_mut().unwrap_unchecked().node_mask_8 = table_ref.node_mask_8;
                cloned.as_ptr().as_mut().unwrap_unchecked().free = RawLuaTableFree {
                    last_free: table_ref.free.last_free,
                };
                ptr::copy_nonoverlapping(table_ref.node, node, size);
            }

            Ok(cloned)
        }
    }
}

impl Table {
    /// `luaH_clear`
    ///
    /// # Safety
    ///
    /// The table must be a live record owned by the active VM and exclusively
    /// mutable for the duration of the call. Any outstanding element or node
    /// cursors must not be used after their slots are cleared.
    pub unsafe fn clear(&self) {
        unsafe {
            for index in 0..self.as_ptr().as_ref().unwrap_unchecked().size_array as usize {
                self.array_slot(index).set_nil();
            }

            self.maybe_set_aboundary(0);

            if !self.has_dummy_node() {
                let size = self.node_count();
                self.as_ptr().as_mut().unwrap_unchecked().free = RawLuaTableFree {
                    last_free: size as i32,
                };

                for index in 0..size {
                    let node = self.node(index as i32);
                    node.set_key_from_value(nil_object());
                    node.value_unchecked().set_nil();
                    node.key().set_next(0);
                }
            }

            self.as_ptr().as_mut().unwrap_unchecked().tm_cache = !0;
        }
    }
}