/src/moddable/xs/sources/xsMapSet.c

Source
/*
 * Copyright (c) 2016-2026  Moddable Tech, Inc.
 *
 *   This file is part of the Moddable SDK Runtime.
 * 
 *   The Moddable SDK Runtime is free software: you can redistribute it and/or modify
 *   it under the terms of the GNU Lesser General Public License as published by
 *   the Free Software Foundation, either version 3 of the License, or
 *   (at your option) any later version.
 * 
 *   The Moddable SDK Runtime is distributed in the hope that it will be useful,
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *   GNU Lesser General Public License for more details.
 * 
 *   You should have received a copy of the GNU Lesser General Public License
 *   along with the Moddable SDK Runtime.  If not, see <http://www.gnu.org/licenses/>.
 *
 * This file incorporates work covered by the following copyright and  
 * permission notice:  
 *
 *       Copyright (C) 2010-2016 Marvell International Ltd.
 *       Copyright (C) 2002-2010 Kinoma, Inc.
 *
 *       Licensed under the Apache License, Version 2.0 (the "License");
 *       you may not use this file except in compliance with the License.
 *       You may obtain a copy of the License at
 *
 *        http://www.apache.org/licenses/LICENSE-2.0
 *
 *       Unless required by applicable law or agreed to in writing, software
 *       distributed under the License is distributed on an "AS IS" BASIS,
 *       WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *       See the License for the specific language governing permissions and
 *       limitations under the License.
 */

#include "xsAll.h"

#ifndef mxTableMinLength
  #define mxTableMinLength (1)
#endif
#ifndef mxTableMaxLength
  #define mxTableMaxLength (1024 * 1024)
#endif
#define mxTableThreshold(LENGTH) (((LENGTH) >> 1) + ((LENGTH) >> 2))

static txSlot* fxCheckMapInstance(txMachine* the, txSlot* slot, txBoolean mutable);
static txSlot* fxCheckMapKey(txMachine* the);
static txSlot* fxNewMapIteratorInstance(txMachine* the, txSlot* iterable, txInteger kind);

static txSlot* fxCheckSetInstance(txMachine* the, txSlot* slot, txBoolean mutable);
static txSlot* fxCheckSetValue(txMachine* the);

static void fxNewSetResult(txMachine* the, txSlot* table, txSlot* list, txSlot** tableAddress, txSlot** listAddress);
static txSlot* fxCheckSetRecord(txMachine* the, txInteger* otherSize, txSlot** otherHas, txSlot** otherKeys);
static txBoolean fxSetRecordHas(txMachine* the, txSlot* other, txSlot* otherHas, txSlot* value);
static void fxSetRecordKeys(txMachine* the, txSlot* other, txSlot* otherKeys, txSlot** iterator, txSlot** next, txSlot** value);

static txSlot* fxNewSetIteratorInstance(txMachine* the, txSlot* iterable, txInteger kind);

static txSlot* fxCanonicalizeKeyedCollectionKey(txSlot* key);
static void fxClearEntries(txMachine* the, txSlot* table, txSlot* list, txBoolean paired);
static txBoolean fxDeleteEntry(txMachine* the, txSlot* table, txSlot* list, txSlot* slot, txBoolean paired, txBoolean fit); 
static txSlot* fxGetEntry(txMachine* the, txSlot* table, txSlot* slot);
static void fxPurgeEntries(txMachine* the, txSlot* list);
static void fxResizeEntries(txMachine* the, txSlot* table, txSlot* list);
static void fxSetEntry(txMachine* the, txSlot* table, txSlot* list, txSlot* slot, txSlot* pair, txBoolean get); 
static txBoolean fxTestEntry(txMachine* the, txSlot* a, txSlot* b);

static txSlot* fxCanBeHeldWeakly(txMachine* the, txSlot* slot);

static txSlot* fxCheckWeakMapInstance(txMachine* the, txSlot* slot, txBoolean mutable);
static txSlot* fxCheckWeakMapKey(txMachine* the, txBoolean mutable);

static txSlot* fxCheckWeakSetInstance(txMachine* the, txSlot* slot, txBoolean mutable);
static txSlot* fxCheckWeakSetValue(txMachine* the, txBoolean mutable);

static txBoolean fxDeleteWeakEntry(txMachine* the, txSlot* link, txSlot* slot); 
static txSlot* fxGetWeakEntry(txMachine* the, txSlot* link, txSlot* slot);
static void fxSetWeakEntry(txMachine* the, txSlot* link, txSlot* slot, txSlot* pair, txBoolean get); 

static void fxKeepDuringJobs(txMachine* the, txSlot* target);
static txSlot* fxNewWeakRefInstance(txMachine* the);

static void fx_FinalizationRegistryCleanup(txMachine* the, txSlot* registry, txSlot* callback);

void fxBuildMapSet(txMachine* the)
{
  txSlot* slot;
  txSlot* property;
  
  /* MAP */
  mxPush(mxObjectPrototype);
  slot = fxLastProperty(the, fxNewObjectInstance(the));
  slot = fxNextHostAccessorProperty(the, slot, mxCallback(fx_Map_prototype_size), C_NULL, mxID(_size), XS_DONT_ENUM_FLAG);
  slot = fxNextHostFunctionProperty(the, slot, mxCallback(fx_Map_prototype_clear), 0, mxID(_clear), XS_DONT_ENUM_FLAG);
  slot = fxNextHostFunctionProperty(the, slot, mxCallback(fx_Map_prototype_delete), 1, mxID(_delete), XS_DONT_ENUM_FLAG);
  property = slot = fxNextHostFunctionProperty(the, slot, mxCallback(fx_Map_prototype_entries), 0, mxID(_entries), XS_DONT_ENUM_FLAG);
  slot = fxNextHostFunctionProperty(the, slot, mxCallback(fx_Map_prototype_forEach), 1, mxID(_forEach), XS_DONT_ENUM_FLAG);
  slot = fxNextHostFunctionProperty(the, slot, mxCallback(fx_Map_prototype_get), 1, mxID(_get), XS_DONT_ENUM_FLAG);
  slot = fxNextHostFunctionProperty(the, slot, mxCallback(fx_Map_prototype_has), 1, mxID(_has), XS_DONT_ENUM_FLAG);
  slot = fxNextHostFunctionProperty(the, slot, mxCallback(fx_Map_prototype_keys), 0, mxID(_keys), XS_DONT_ENUM_FLAG);
  slot = fxNextHostFunctionProperty(the, slot, mxCallback(fx_Map_prototype_set), 2, mxID(_set), XS_DONT_ENUM_FLAG);
  slot = fxNextHostFunctionProperty(the, slot, mxCallback(fx_Map_prototype_values), 0, mxID(_values), XS_DONT_ENUM_FLAG);
  slot = fxNextSlotProperty(the, slot, property, mxID(_Symbol_iterator), XS_DONT_ENUM_FLAG);
  slot = fxNextStringXProperty(the, slot, "Map", mxID(_Symbol_toStringTag), XS_DONT_ENUM_FLAG | XS_DONT_SET_FLAG);
#if mxECMAScript2026
  slot = fxNextHostFunctionProperty(the, slot, mxCallback(fx_Map_prototype_getOrInsert), 2, mxID(_getOrInsert), XS_DONT_ENUM_FLAG);
  slot = fxNextHostFunctionProperty(the, slot, mxCallback(fx_Map_prototype_getOrInsertComputed), 2, mxID(_getOrInsertComputed), XS_DONT_ENUM_FLAG);
#endif
  mxMapPrototype = *the->stack;
  slot = fxBuildHostConstructor(the, mxCallback(fx_Map), 0, mxID(_Map));
  mxMapConstructor = *the->stack;
  slot = fxLastProperty(the, slot);
  slot = fxNextHostAccessorProperty(the, slot, mxCallback(fx_species_get), C_NULL, mxID(_Symbol_species), XS_DONT_ENUM_FLAG);
#if mxECMAScript2024
  slot = fxNextHostFunctionProperty(the, slot, mxCallback(fx_Map_groupBy), 2, mxID(_groupBy), XS_DONT_ENUM_FLAG);
#endif
  mxPop();
  
  mxPush(mxIteratorPrototype);
  slot = fxLastProperty(the, fxNewObjectInstance(the));
  slot = fxNextHostFunctionProperty(the, slot, mxCallback(fx_MapIterator_prototype_next), 0, mxID(_next), XS_DONT_DELETE_FLAG | XS_DONT_ENUM_FLAG);
  slot = fxNextStringXProperty(the, slot, "Map Iterator", mxID(_Symbol_toStringTag), XS_DONT_ENUM_FLAG | XS_DONT_SET_FLAG);
  mxPull(mxMapIteratorPrototype);
  
  /* SET */
  mxPush(mxObjectPrototype);
  slot = fxLastProperty(the, fxNewObjectInstance(the));
  slot = fxNextHostAccessorProperty(the, slot, mxCallback(fx_Set_prototype_size), C_NULL, mxID(_size), XS_DONT_ENUM_FLAG);
  slot = fxNextHostFunctionProperty(the, slot, mxCallback(fx_Set_prototype_add), 1, mxID(_add), XS_DONT_ENUM_FLAG);
  slot = fxNextHostFunctionProperty(the, slot, mxCallback(fx_Set_prototype_clear), 0, mxID(_clear), XS_DONT_ENUM_FLAG);
  slot = fxNextHostFunctionProperty(the, slot, mxCallback(fx_Set_prototype_delete), 1, mxID(_delete), XS_DONT_ENUM_FLAG);
  slot = fxNextHostFunctionProperty(the, slot, mxCallback(fx_Set_prototype_entries), 0, mxID(_entries), XS_DONT_ENUM_FLAG);
  slot = fxNextHostFunctionProperty(the, slot, mxCallback(fx_Set_prototype_forEach), 1, mxID(_forEach), XS_DONT_ENUM_FLAG);
  slot = fxNextHostFunctionProperty(the, slot, mxCallback(fx_Set_prototype_has), 1, mxID(_has), XS_DONT_ENUM_FLAG);
  property = slot = fxNextHostFunctionProperty(the, slot, mxCallback(fx_Set_prototype_values), 0, mxID(_values), XS_DONT_ENUM_FLAG);
  slot = fxNextSlotProperty(the, slot, property, mxID(_keys), XS_DONT_ENUM_FLAG);
  slot = fxNextSlotProperty(the, slot, property, mxID(_Symbol_iterator), XS_DONT_ENUM_FLAG);
  slot = fxNextStringXProperty(the, slot, "Set", mxID(_Symbol_toStringTag), XS_DONT_ENUM_FLAG | XS_DONT_SET_FLAG);
#if mxECMAScript2025
  slot = fxNextHostFunctionProperty(the, slot, mxCallback(fx_Set_prototype_difference), 1, mxID(_difference), XS_DONT_ENUM_FLAG);
  slot = fxNextHostFunctionProperty(the, slot, mxCallback(fx_Set_prototype_intersection), 1, mxID(_intersection), XS_DONT_ENUM_FLAG);
  slot = fxNextHostFunctionProperty(the, slot, mxCallback(fx_Set_prototype_isDisjointFrom), 1, mxID(_isDisjointFrom), XS_DONT_ENUM_FLAG);
  slot = fxNextHostFunctionProperty(the, slot, mxCallback(fx_Set_prototype_isSubsetOf), 1, mxID(_isSubsetOf), XS_DONT_ENUM_FLAG);
  slot = fxNextHostFunctionProperty(the, slot, mxCallback(fx_Set_prototype_isSupersetOf), 1, mxID(_isSupersetOf), XS_DONT_ENUM_FLAG);
  slot = fxNextHostFunctionProperty(the, slot, mxCallback(fx_Set_prototype_symmetricDifference), 1, mxID(_symmetricDifference), XS_DONT_ENUM_FLAG);
  slot = fxNextHostFunctionProperty(the, slot, mxCallback(fx_Set_prototype_union), 1, mxID(_union), XS_DONT_ENUM_FLAG);
#endif
  mxSetPrototype = *the->stack;
  slot = fxBuildHostConstructor(the, mxCallback(fx_Set), 0, mxID(_Set));
  mxSetConstructor = *the->stack;
  slot = fxLastProperty(the, slot);
  slot = fxNextHostAccessorProperty(the, slot, mxCallback(fx_species_get), C_NULL, mxID(_Symbol_species), XS_DONT_ENUM_FLAG);
  mxPop();
  
  mxPush(mxIteratorPrototype);
  slot = fxLastProperty(the, fxNewObjectInstance(the));
  slot = fxNextHostFunctionProperty(the, slot, mxCallback(fx_SetIterator_prototype_next), 0, mxID(_next), XS_DONT_DELETE_FLAG | XS_DONT_ENUM_FLAG);
  slot = fxNextStringXProperty(the, slot, "Set Iterator", mxID(_Symbol_toStringTag), XS_DONT_ENUM_FLAG | XS_DONT_SET_FLAG);
  mxPull(mxSetIteratorPrototype);

  /* WEAK MAP */
  mxPush(mxObjectPrototype);
  slot = fxLastProperty(the, fxNewObjectInstance(the));
  slot = fxNextHostFunctionProperty(the, slot, mxCallback(fx_WeakMap_prototype_delete), 1, mxID(_delete), XS_DONT_ENUM_FLAG);
  slot = fxNextHostFunctionProperty(the, slot, mxCallback(fx_WeakMap_prototype_get), 1, mxID(_get), XS_DONT_ENUM_FLAG);
  slot = fxNextHostFunctionProperty(the, slot, mxCallback(fx_WeakMap_prototype_has), 1, mxID(_has), XS_DONT_ENUM_FLAG);
  slot = fxNextHostFunctionProperty(the, slot, mxCallback(fx_WeakMap_prototype_set), 2, mxID(_set), XS_DONT_ENUM_FLAG);
  slot = fxNextStringXProperty(the, slot, "WeakMap", mxID(_Symbol_toStringTag), XS_DONT_ENUM_FLAG | XS_DONT_SET_FLAG);
#if mxECMAScript2026
  slot = fxNextHostFunctionProperty(the, slot, mxCallback(fx_WeakMap_prototype_getOrInsert), 2, mxID(_getOrInsert), XS_DONT_ENUM_FLAG);
  slot = fxNextHostFunctionProperty(the, slot, mxCallback(fx_WeakMap_prototype_getOrInsertComputed), 2, mxID(_getOrInsertComputed), XS_DONT_ENUM_FLAG);
#endif
  mxWeakMapPrototype = *the->stack;
  slot = fxBuildHostConstructor(the, mxCallback(fx_WeakMap), 0, mxID(_WeakMap));
  mxWeakMapConstructor = *the->stack;
  mxPop();
  
  /* WEAK SET */
  mxPush(mxObjectPrototype);
  slot = fxLastProperty(the, fxNewObjectInstance(the));
  slot = fxNextHostFunctionProperty(the, slot, mxCallback(fx_WeakSet_prototype_add), 1, mxID(_add), XS_DONT_ENUM_FLAG);
  slot = fxNextHostFunctionProperty(the, slot, mxCallback(fx_WeakSet_prototype_delete), 1, mxID(_delete), XS_DONT_ENUM_FLAG);
  slot = fxNextHostFunctionProperty(the, slot, mxCallback(fx_WeakSet_prototype_has), 1, mxID(_has), XS_DONT_ENUM_FLAG);
  slot = fxNextStringXProperty(the, slot, "WeakSet", mxID(_Symbol_toStringTag), XS_DONT_ENUM_FLAG | XS_DONT_SET_FLAG);
  mxWeakSetPrototype = *the->stack;
  slot = fxBuildHostConstructor(the, mxCallback(fx_WeakSet), 0, mxID(_WeakSet));
  mxWeakSetConstructor = *the->stack;
  mxPop();
  
  /* WEAK REF */
  mxPush(mxObjectPrototype);
  slot = fxLastProperty(the, fxNewObjectInstance(the));
  slot = fxNextHostFunctionProperty(the, slot, mxCallback(fx_WeakRef_prototype_deref), 0, mxID(_deref), XS_DONT_ENUM_FLAG);
  slot = fxNextStringXProperty(the, slot, "WeakRef", mxID(_Symbol_toStringTag), XS_DONT_ENUM_FLAG | XS_DONT_SET_FLAG);
  mxWeakRefPrototype = *the->stack;
  slot = fxBuildHostConstructor(the, mxCallback(fx_WeakRef), 1, mxID(_WeakRef));
  mxWeakRefConstructor = *the->stack;
  mxPop();
  
  /* FINALIZATION REGISTRY */
  mxPush(mxObjectPrototype);
  slot = fxLastProperty(the, fxNewObjectInstance(the));
//  slot = fxNextHostFunctionProperty(the, slot, mxCallback(fx_FinalizationRegistry_prototype_cleanupSome), 0, mxID(_cleanupSome), XS_DONT_ENUM_FLAG);
  slot = fxNextHostFunctionProperty(the, slot, mxCallback(fx_FinalizationRegistry_prototype_register), 2, mxID(_register), XS_DONT_ENUM_FLAG);
  slot = fxNextHostFunctionProperty(the, slot, mxCallback(fx_FinalizationRegistry_prototype_unregister), 1, mxID(_unregister), XS_DONT_ENUM_FLAG);
  slot = fxNextStringXProperty(the, slot, "FinalizationRegistry", mxID(_Symbol_toStringTag), XS_DONT_ENUM_FLAG | XS_DONT_SET_FLAG);
  mxFinalizationRegistryPrototype = *the->stack;
  slot = fxBuildHostConstructor(the, mxCallback(fx_FinalizationRegistry), 1, mxID(_FinalizationRegistry));
  mxFinalizationRegistryConstructor = *the->stack;
  mxPop();
}

txSlot* fxCheckMapInstance(txMachine* the, txSlot* slot, txBoolean mutable)
{
  if (slot->kind == XS_REFERENCE_KIND) {
    txSlot* instance = slot->value.reference;
    if (((slot = instance->next)) && (slot->flag & XS_INTERNAL_FLAG) && (slot->kind == XS_MAP_KIND) && (instance != mxMapPrototype.value.reference)) {
      if (mutable && (slot->flag & XS_DONT_SET_FLAG))
        mxTypeError("this: read-only Map instance");
      return instance;
    }
  }
  mxTypeError("this: not a Map instance");
  return C_NULL;
}

txSlot* fxCheckMapKey(txMachine* the)
{
  if (mxArgc > 0) {
    txSlot* slot = mxArgv(0);
    return slot;
  }
  mxTypeError("no key");
  return C_NULL;
}

txSlot* fxNewMapInstance(txMachine* the)
{
  txSlot* map;
  txSlot* table;
  txSlot* list;
  txSlot* size;
  txSlot** address;
  map = fxNewSlot(the);
  map->kind = XS_INSTANCE_KIND;
  map->value.instance.garbage = C_NULL;
  map->value.instance.prototype = the->stack->value.reference;
  the->stack->kind = XS_REFERENCE_KIND;
  the->stack->value.reference = map;
  table = map->next = fxNewSlot(the);
  list = table->next = fxNewSlot(the);
  size = list->next = fxNewSlot(the);
  address = (txSlot**)fxNewChunk(the, mxTableMinLength * sizeof(txSlot*));
  c_memset(address, 0, mxTableMinLength * sizeof(txSlot*));
  /* TABLE */
  table->flag = XS_INTERNAL_FLAG;
  table->kind = XS_MAP_KIND;
  table->value.table.address = address;
  table->value.table.length = mxTableMinLength;
  /* LIST */
  list->flag = XS_INTERNAL_FLAG;
  list->kind = XS_LIST_KIND;
  list->value.list.first = C_NULL;
  list->value.list.last = C_NULL;
  /* SIZE */
  size->flag = XS_INTERNAL_FLAG;
  size->kind = XS_INTEGER_KIND;
  size->value.integer = 0;
  return map;
}

void fx_Map(txMachine* the)
{
  txSlot *function, *iterable, *iterator, *next, *value;
  if (!mxHasTarget)
    mxTypeError("call: Map");
  mxPushSlot(mxTarget);
  fxGetPrototypeFromConstructor(the, &mxMapPrototype);
  fxNewMapInstance(the);
  mxPullSlot(mxResult);
  if (mxArgc < 1)
    return;
  iterable = mxArgv(0);
  if ((iterable->kind == XS_UNDEFINED_KIND) || (iterable->kind == XS_NULL_KIND))
    return;
  mxPushSlot(mxResult);
  mxGetID(mxID(_set)); 
  function = the->stack;  
  if (!fxIsCallable(the, function))  
    mxTypeError("result.set: not a function");
  mxTemporary(iterator);
  mxTemporary(next);
  fxGetIterator(the, iterable, iterator, next, 0);  
  mxTemporary(value);
  while (fxIteratorNext(the, iterator, next, value)) {
    mxTry(the) {
      if (value->kind != XS_REFERENCE_KIND)
        mxTypeError("item: not an object");
      mxPushSlot(mxResult);
      mxPushSlot(function);
      mxCall();
      mxPushSlot(value);
      mxGetIndex(0);
      mxPushSlot(value);
      mxGetIndex(1);
      mxRunCount(2);
      mxPop();
    }
    mxCatch(the) {
      fxIteratorReturn(the, iterator, 1);
      fxJump(the);
    }
  }
}

static void fx_Map_groupByAux(txMachine* the)
{
  txSlot* instance = mxResult->value.reference;
  txSlot* table = instance->next;
  txSlot* list = table->next;
  txSlot* key = the->stack;
  txSlot* entry = fxGetEntry(the, table, key);
  if (entry)
    mxPushSlot(entry->next);
  else {
    mxPush(mxArrayPrototype);
    fxNewArrayInstance(the);
    fxSetEntry(the, table, list, key, the->stack, 0);
  }
}

void fx_Map_groupBy(txMachine* the)
{
  txSlot *instance, *key, *value;
  mxPush(mxMapPrototype);
  instance = fxNewMapInstance(the);
  mxPullSlot(mxResult);
  fxGroupBy(the, fx_Map_groupByAux);
  key = instance->next->next->value.list.first;
  while (key) {
    value = key->next;
    fxCacheArray(the, value->value.reference);
    key = value->next;
  }
}

void fx_Map_prototype_clear(txMachine* the)
{
  txSlot* instance = fxCheckMapInstance(the, mxThis, XS_MUTABLE);
  txSlot* table = instance->next;
  txSlot* list = table->next;
  fxClearEntries(the, table, list, 1);
}

void fx_Map_prototype_delete(txMachine* the)
{
  txSlot* instance = fxCheckMapInstance(the, mxThis, XS_MUTABLE);
  txSlot* table = instance->next;
  txSlot* list = table->next;
  txSlot* key = fxCheckMapKey(the);
  mxResult->value.boolean = fxDeleteEntry(the, table, list, key, 1, 1);
  mxResult->kind = XS_BOOLEAN_KIND;
}

void fx_Map_prototype_entries(txMachine* the)
{
  fxCheckMapInstance(the, mxThis, XS_IMMUTABLE);
  fxNewMapIteratorInstance(the, mxThis, 2);
}

void fx_Map_prototype_forEach(txMachine* the)
{
  txSlot* instance = fxCheckMapInstance(the, mxThis, XS_IMMUTABLE);
  txSlot* table = instance->next;
  txSlot* list = table->next;
  txSlot* function = fxArgToCallback(the, 0);
  txSlot* key;
  txSlot* value;
  mxPushList();
  key = the->stack->value.list.first = list->value.list.first;
  while (key) {
    value = key->next;
    if (!(key->flag & XS_DONT_ENUM_FLAG)) {
      /* THIS */
      if (mxArgc > 1)
        mxPushSlot(mxArgv(1));
      else
        mxPushUndefined();
      /* FUNCTION */
      mxPushSlot(function);
      mxCall();
      /* ARGUMENTS */
      mxPushSlot(value);
      mxPushSlot(key);
      mxPushSlot(mxThis);
      mxRunCount(3);
      mxPop();
    }
    key = the->stack->value.list.first = value->next;
  }
  mxPop();
}

void fx_Map_prototype_get(txMachine* the)
{
  txSlot* instance = fxCheckMapInstance(the, mxThis, XS_IMMUTABLE);
  txSlot* table = instance->next;
  txSlot* key = fxCheckMapKey(the);
  txSlot* result = fxGetEntry(the, table, key);
  if (result) {
    txSlot* value = result->next;
    mxResult->kind = value->kind;
    mxResult->value = value->value;
  }
}

void fx_Map_prototype_getOrInsert(txMachine* the)
{
  txSlot* instance = fxCheckMapInstance(the, mxThis, XS_MUTABLE);
  txSlot* table = instance->next;
  txSlot* list = table->next;
  txSlot* key = fxCheckMapKey(the);
  *mxResult = (mxArgc > 1) ? *mxArgv(1) : mxUndefined;
  fxSetEntry(the, table, list, key, mxResult, 1);
}

void fx_Map_prototype_getOrInsertComputed(txMachine* the)
{
  txSlot* instance = fxCheckMapInstance(the, mxThis, XS_MUTABLE);
  txSlot* table = instance->next;
  txSlot* list = table->next;
  txSlot* function = fxArgToCallback(the, 1);
  txSlot* key = fxCheckMapKey(the);
  txSlot* result = fxGetEntry(the, table, key);
  if (result) {
    txSlot* value = result->next;
    mxResult->kind = value->kind;
    mxResult->value = value->value;
    return;
  }
  mxPushUndefined();
  mxPushSlot(function);
  mxCall();
  mxPushSlot(key);
  mxRunCount(1);
  mxPullSlot(mxResult);
  fxSetEntry(the, table, list, key, mxResult, 0);
}

void fx_Map_prototype_has(txMachine* the)
{
  txSlot* instance = fxCheckMapInstance(the, mxThis, XS_IMMUTABLE);
  txSlot* table = instance->next;
  txSlot* key = fxCheckMapKey(the);
  txSlot* result = fxGetEntry(the, table, key);
  mxResult->kind = XS_BOOLEAN_KIND;
  mxResult->value.boolean = (result) ? 1 : 0;
}

void fx_Map_prototype_keys(txMachine* the)
{
  fxCheckMapInstance(the, mxThis, XS_IMMUTABLE);
  fxNewMapIteratorInstance(the, mxThis, 0);
}

void fx_Map_prototype_set(txMachine* the)
{
  txSlot* instance = fxCheckMapInstance(the, mxThis, XS_MUTABLE);
  txSlot* table = instance->next;
  txSlot* list = table->next;
  txSlot* key = fxCheckMapKey(the);
  fxSetEntry(the, table, list, key, (mxArgc > 1) ? mxArgv(1) : &mxUndefined, 0);
  *mxResult = *mxThis;
}

void fx_Map_prototype_size(txMachine* the)
{
  txSlot* instance = fxCheckMapInstance(the, mxThis, XS_IMMUTABLE);
  txSlot* table = instance->next;
  txSlot* list = table->next;
  mxResult->kind = XS_INTEGER_KIND;
  mxResult->value.integer = list->next->value.integer;
}

void fx_Map_prototype_values(txMachine* the)
{
  fxCheckMapInstance(the, mxThis, XS_IMMUTABLE);
  fxNewMapIteratorInstance(the, mxThis, 1);
}

txSlot* fxNewMapIteratorInstance(txMachine* the, txSlot* iterable, txInteger kind) 
{
  txSlot* instance;
  txSlot* property;
  mxPush(mxMapIteratorPrototype);
  instance = fxNewIteratorInstance(the, iterable, mxID(_Map));
  property = fxLastProperty(the, instance);
  property->kind = XS_LIST_KIND;
  property->value.list.first = C_NULL;
  property->value.list.last = C_NULL;
  property = fxNextIntegerProperty(the, property, kind, XS_NO_ID, XS_INTERNAL_FLAG);
  mxPullSlot(mxResult);
  return instance;
}

void fx_MapIterator_prototype_next(txMachine* the)
{
  txSlot* iterator = fxCheckIteratorInstance(the, mxThis, mxID(_Map));
  txSlot* result = iterator->next;
  txSlot* iterable = result->next;
  mxResult->kind = result->kind;
  mxResult->value = result->value;
  result = fxCheckIteratorResult(the, result);
  if (result->next->value.boolean == 0) {
    txSlot* list = iterable->next;
    txInteger kind = list->next->value.integer;
    txSlot* key = list->value.list.first;
    if (key)
      key = key->next->next;
    else
      key = iterable->value.reference->next->next->value.list.first;
    while (key && (key->flag & XS_DONT_ENUM_FLAG))
      key = key->next->next;
    if (key) {
      txSlot* value = key->next;
      if (kind == 2) {
        mxPushSlot(key);
        mxPushSlot(value);
        fxConstructArrayEntry(the, result);
      }
      else if (kind == 1) {
        result->kind = value->kind;
        result->value = value->value;
      }
      else {
        result->kind = key->kind;
        result->value = key->value;
      }
      list->value.list.first = key;
    }
    else {
      result->kind = XS_UNDEFINED_KIND;
      result->next->value.boolean = 1;
      list->value.list.first = C_NULL;
    }
  }
}

txSlot* fxCheckSetInstance(txMachine* the, txSlot* slot, txBoolean mutable)
{
  if (slot->kind == XS_REFERENCE_KIND) {
    txSlot* instance = slot->value.reference;
    if (((slot = instance->next)) && (slot->flag & XS_INTERNAL_FLAG) && (slot->kind == XS_SET_KIND) && (instance != mxSetPrototype.value.reference)) {
      if (mutable && (slot->flag & XS_DONT_SET_FLAG))
        mxTypeError("this: read-only Set instance");
      return instance;
    }
  }
  mxTypeError("this: not a Set instance");
  return C_NULL;
}

txSlot* fxCheckSetValue(txMachine* the)
{
  if (mxArgc > 0) {
    txSlot* slot = mxArgv(0);
    return slot;
  }
  mxTypeError("no value");
  return C_NULL;
}

txSlot* fxCheckSetRecord(txMachine* the, txInteger* otherSize, txSlot** otherHas, txSlot** otherKeys)
{
  txSlot* other;
  txNumber size;
  if (mxArgc < 1)
    mxTypeError("other is no object");
  other = mxArgv(0);  
  if (!mxIsReference(other))
    mxTypeError("other is no object");
    
  mxPushSlot(other);
  mxGetID(mxID(_size));  
  size = fxToNumber(the, the->stack);
  if (c_isnan(size))
    mxTypeError("other.size is NaN");
  size = c_trunc(size);
  if (size < 0)
    mxRangeError("other.size < 0");
  if (otherSize)
    *otherSize= (txInteger)size;
  mxPop();
  
  mxPushSlot(other);
  mxGetID(mxID(_has));
  if (!fxIsCallable(the, the->stack))
    mxTypeError("other.has is no function");
  if (otherHas)
    *otherHas = the->stack;
      
  mxPushSlot(other);
  mxGetID(mxID(_keys));
  if (!fxIsCallable(the, the->stack))
    mxTypeError("other.keys is no function");
  if (otherKeys)
    *otherKeys = the->stack;
    
  return other;
}

txSlot* fxNewSetInstance(txMachine* the, txInteger tableLength)
{
  txSlot* set;
  txSlot* table;
  txSlot* list;
  txSlot* size;
  txSlot** address;
  set = fxNewSlot(the);
  set->kind = XS_INSTANCE_KIND;
  set->value.instance.garbage = C_NULL;
  set->value.instance.prototype = the->stack->value.reference;
  the->stack->kind = XS_REFERENCE_KIND;
  the->stack->value.reference = set;
  table = set->next = fxNewSlot(the);
  list = table->next = fxNewSlot(the);
  size = list->next = fxNewSlot(the);
  address = (txSlot**)fxNewChunk(the, tableLength * sizeof(txSlot*));
  c_memset(address, 0, tableLength * sizeof(txSlot*));
  /* TABLE */
  table->flag = XS_INTERNAL_FLAG;
  table->kind = XS_SET_KIND;
  table->value.table.address = address;
  table->value.table.length = tableLength;
  /* LIST */
  list->flag = XS_INTERNAL_FLAG;
  list->kind = XS_LIST_KIND;
  list->value.list.first = C_NULL;
  list->value.list.last = C_NULL;
  /* SIZE */
  size->flag = XS_INTERNAL_FLAG;
  size->kind = XS_INTEGER_KIND;
  size->value.integer = 0;
  return set;
}

void fxNewSetResult(txMachine* the, txSlot* table, txSlot* list, txSlot** tableAddress, txSlot** listAddress)
{
  txSlot *resultInstance, *resultTable, *resultList, *value;
  mxPush(mxSetPrototype);
  resultInstance = fxNewSetInstance(the, (list) ? table->value.table.length : mxTableMinLength);
  mxPullSlot(mxResult);
  resultTable = resultInstance->next;
  resultList = resultTable->next;
  if (list) {
    value = list->value.list.first;
    while (value) {
      fxSetEntry(the, resultTable, resultList, value, C_NULL, 0);
      value = value->next;
    }  
  }  
  *tableAddress = resultTable;
  *listAddress = resultList;
}

txBoolean fxSetRecordHas(txMachine* the, txSlot* other, txSlot* otherHas, txSlot* value)
{
  txBoolean result;
  mxPushSlot(other);
  mxPushSlot(otherHas);
  mxCall();
  mxPushSlot(value);
  mxRunCount(1);
  result = fxToBoolean(the, the->stack);
  mxPop();
  return result;
}

void fxSetRecordKeys(txMachine* the, txSlot* other, txSlot* otherKeys, txSlot** iterator, txSlot** next, txSlot** value)
{
  mxPushSlot(other);
  mxPushSlot(otherKeys);
  mxCall();
  mxRunCount(0);
  *iterator = the->stack;
  mxDub();
  mxGetID(mxID(_next));
  *next = the->stack;
  mxPushUndefined();
  *value = the->stack;
}

void fx_Set(txMachine* the)
{
  txSlot *function, *iterable, *iterator, *next, *value;
  if (!mxHasTarget)
    mxTypeError("call: Set");
  mxPushSlot(mxTarget);
  fxGetPrototypeFromConstructor(the, &mxSetPrototype);
  fxNewSetInstance(the, mxTableMinLength);
  mxPullSlot(mxResult);
  if (mxArgc < 1)
    return;
  iterable = mxArgv(0);
  if ((iterable->kind == XS_UNDEFINED_KIND) || (iterable->kind == XS_NULL_KIND))
    return;
  mxPushSlot(mxResult);
  mxGetID(mxID(_add)); 
  function = the->stack;  
  if (!fxIsCallable(the, function))  
    mxTypeError("result.add: not a function");
  mxTemporary(iterator);
  mxTemporary(next);
  fxGetIterator(the, iterable, iterator, next, 0);  
  mxTemporary(value);
  while (fxIteratorNext(the, iterator, next, value)) {
    mxTry(the) {
      mxPushSlot(mxResult);
      mxPushSlot(function);
      mxCall();
      mxPushSlot(value);
      mxRunCount(1);
      mxPop();
    }
    mxCatch(the) {
      fxIteratorReturn(the, iterator, 1);
      fxJump(the);
    }
  }
}

void fx_Set_prototype_add(txMachine* the)
{
  txSlot* instance = fxCheckSetInstance(the, mxThis, XS_MUTABLE);
  txSlot* table = instance->next;
  txSlot* list = table->next;
  txSlot* value = fxCheckSetValue(the);
  fxSetEntry(the, table, list, value, C_NULL, 0);
  *mxResult = *mxThis;
}

void fx_Set_prototype_clear(txMachine* the)
{
  txSlot* instance = fxCheckSetInstance(the, mxThis, XS_MUTABLE);
  txSlot* table = instance->next;
  txSlot* list = table->next;
  fxClearEntries(the, table, list, 0);
}

void fx_Set_prototype_delete(txMachine* the)
{
  txSlot* instance = fxCheckSetInstance(the, mxThis, XS_MUTABLE);
  txSlot* table = instance->next;
  txSlot* list = table->next;
  txSlot* value = fxCheckSetValue(the);
  mxResult->value.boolean = fxDeleteEntry(the, table, list, value, 0, 1);
  mxResult->kind = XS_BOOLEAN_KIND;
}

void fx_Set_prototype_difference(txMachine* the)
{
  txSlot* stack = the->stack;
  txSlot* instance = fxCheckSetInstance(the, mxThis, XS_IMMUTABLE);
  txSlot* table = instance->next;
  txSlot* list = table->next;
  txInteger size = list->next->value.integer, otherSize;
  txSlot *otherHas, *otherKeys, *resultTable, *resultList, *iterator, *next, *value;
  txSlot *other = fxCheckSetRecord(the, &otherSize, &otherHas, &otherKeys);
  fxNewSetResult(the, table, list, &resultTable, &resultList);
  if (size <= otherSize) {
    mxPushList();
    value = the->stack->value.list.first = list->value.list.first;
    while (value) {
      if (!(value->flag & XS_DONT_ENUM_FLAG)) {
        if (fxSetRecordHas(the, other, otherHas, value))
          fxDeleteEntry(the, resultTable, resultList, value, 0, 0);
      }
      value = the->stack->value.list.first = value->next;
    }
  }
  else {
    fxSetRecordKeys(the, other, otherKeys, &iterator, &next, &value);
    while (fxIteratorNext(the, iterator, next, value)) {
      fxCanonicalizeKeyedCollectionKey(value);
      fxDeleteEntry(the, resultTable, resultList, value, 0, 0);
    }
  }
  fxResizeEntries(the, resultTable, resultList);
  fxPurgeEntries(the, resultList);
  the->stack = stack;
}

void fx_Set_prototype_entries(txMachine* the)
{
  fxCheckSetInstance(the, mxThis, XS_IMMUTABLE);
  fxNewSetIteratorInstance(the, mxThis, 2);
}

void fx_Set_prototype_forEach(txMachine* the)
{
  txSlot* instance = fxCheckSetInstance(the, mxThis, XS_IMMUTABLE);
  txSlot* table = instance->next;
  txSlot* list = table->next;
  txSlot* function = fxArgToCallback(the, 0);
  txSlot* value;
  mxPushList();
  value = the->stack->value.list.first = list->value.list.first;
  while (value) {
    if (!(value->flag & XS_DONT_ENUM_FLAG)) {
      /* THIS */
      if (mxArgc > 1)
        mxPushSlot(mxArgv(1));
      else
        mxPushUndefined();
      /* FUNCTION */
      mxPushSlot(function);
      mxCall();
      /* ARGUMENTS */
      mxPushSlot(value);
      mxPushSlot(value);
      mxPushSlot(mxThis);
      mxRunCount(3);
      mxPop();
    }
    value = the->stack->value.list.first = value->next;
  }
  mxPop();
}

void fx_Set_prototype_has(txMachine* the)
{
  txSlot* instance = fxCheckSetInstance(the, mxThis, XS_IMMUTABLE);
  txSlot* table = instance->next;
  txSlot* value = fxCheckSetValue(the);
  txSlot* result = fxGetEntry(the, table, value);
  mxResult->kind = XS_BOOLEAN_KIND;
  mxResult->value.boolean = (result) ? 1 : 0;
}

void fx_Set_prototype_intersection(txMachine* the)
{
  txSlot* stack = the->stack;
  txSlot* instance = fxCheckSetInstance(the, mxThis, XS_IMMUTABLE);
  txSlot* table = instance->next;
  txSlot* list = table->next;
  txInteger size = list->next->value.integer, otherSize;
  txSlot *otherHas, *otherKeys, *resultTable, *resultList, *iterator, *next, *value;
  txSlot *other = fxCheckSetRecord(the, &otherSize, &otherHas, &otherKeys);
  fxNewSetResult(the, table, C_NULL, &resultTable, &resultList);
  if (size <= otherSize) {
    mxPushList();
    value = the->stack->value.list.first = list->value.list.first;
    while (value) {
      if (!(value->flag & XS_DONT_ENUM_FLAG)) {
        if (fxSetRecordHas(the, other, otherHas, value))
          fxSetEntry(the, resultTable, resultList, value, C_NULL, 0);
      }
      value = the->stack->value.list.first = value->next;
    }
  }
  else {
    fxSetRecordKeys(the, other, otherKeys, &iterator, &next, &value);
    while (fxIteratorNext(the, iterator, next, value)) {
      fxCanonicalizeKeyedCollectionKey(value);
      if (fxGetEntry(the, table, value))
        fxSetEntry(the, resultTable, resultList, value, C_NULL, 0);
    }
  }
  the->stack = stack;
}

void fx_Set_prototype_isDisjointFrom(txMachine* the)
{
  txSlot* stack = the->stack;
  txSlot* instance = fxCheckSetInstance(the, mxThis, XS_IMMUTABLE);
  txSlot* table = instance->next;
  txSlot* list = table->next;
  txInteger size = list->next->value.integer, otherSize;
  txSlot *otherHas, *otherKeys, *iterator, *next, *value;
  txSlot *other = fxCheckSetRecord(the, &otherSize, &otherHas, &otherKeys);
  mxResult->value.boolean = 0;
  mxResult->kind = XS_BOOLEAN_KIND;
  if (size <= otherSize) {
    mxPushList();
    value = the->stack->value.list.first = list->value.list.first;
    while (value) {
      if (!(value->flag & XS_DONT_ENUM_FLAG)) {
        if (fxSetRecordHas(the, other, otherHas, value))
          goto bail;
      }
      value = the->stack->value.list.first = value->next;
    }
  }
  else {
    fxSetRecordKeys(the, other, otherKeys, &iterator, &next, &value);
    while (fxIteratorNext(the, iterator, next, value)) {
      if (fxGetEntry(the, table, value)) {
        fxIteratorReturn(the, iterator, 0);
        goto bail;
      }
    }
  }
  mxResult->value.boolean = 1;
bail:
  the->stack = stack;
}

void fx_Set_prototype_isSubsetOf(txMachine* the)
{
  txSlot* stack = the->stack;
  txSlot* instance = fxCheckSetInstance(the, mxThis, XS_IMMUTABLE);
  txSlot* table = instance->next;
  txSlot* list = table->next;
  txInteger size = list->next->value.integer, otherSize;
  txSlot *otherHas, *value;
  txSlot *other = fxCheckSetRecord(the, &otherSize, &otherHas, C_NULL);
  mxResult->value.boolean = 0;
  mxResult->kind = XS_BOOLEAN_KIND;
  if (size > otherSize)
    goto bail;
  mxPushList();
  value = the->stack->value.list.first = list->value.list.first;
  while (value) {
    if (!(value->flag & XS_DONT_ENUM_FLAG)) {
      if (!fxSetRecordHas(the, other, otherHas, value))
        goto bail;
    }
    value = the->stack->value.list.first = value->next;
  }
  mxResult->value.boolean = 1;
bail:
  the->stack = stack;
}

void fx_Set_prototype_isSupersetOf(txMachine* the)
{
  txSlot* stack = the->stack;
  txSlot* instance = fxCheckSetInstance(the, mxThis, XS_IMMUTABLE);
  txSlot* table = instance->next;
  txSlot* list = table->next;
  txInteger size = list->next->value.integer, otherSize;
  txSlot *otherKeys, *iterator, *next, *value;
  txSlot *other = fxCheckSetRecord(the, &otherSize, C_NULL, &otherKeys);
  mxResult->value.boolean = 0;
  mxResult->kind = XS_BOOLEAN_KIND;
  if (size < otherSize)
    goto bail;
  fxSetRecordKeys(the, other, otherKeys, &iterator, &next, &value);
  while (fxIteratorNext(the, iterator, next, value)) {
    if (!fxGetEntry(the, table, value)) {
      fxIteratorReturn(the, iterator, 0);
      goto bail;
    }
  }
  mxResult->value.boolean = 1;
bail:
  the->stack = stack;
}

void fx_Set_prototype_size(txMachine* the)
{
  txSlot* instance = fxCheckSetInstance(the, mxThis, XS_IMMUTABLE);
  txSlot* table = instance->next;
  txSlot* list = table->next;
  mxResult->kind = XS_INTEGER_KIND;
  mxResult->value.integer = list->next->value.integer;
}

void fx_Set_prototype_symmetricDifference(txMachine* the)
{
  txSlot* stack = the->stack;
  txSlot* instance = fxCheckSetInstance(the, mxThis, XS_IMMUTABLE);
  txSlot* table = instance->next;
  txSlot* list = table->next;
  txSlot *otherKeys, *resultTable, *resultList, *iterator, *next, *value;
  txSlot *other = fxCheckSetRecord(the, C_NULL, C_NULL, &otherKeys);
  fxNewSetResult(the, table, list, &resultTable, &resultList);
  fxSetRecordKeys(the, other, otherKeys, &iterator, &next, &value);
  while (fxIteratorNext(the, iterator, next, value)) {
    fxCanonicalizeKeyedCollectionKey(value);
    if (fxGetEntry(the, table, value))
      fxDeleteEntry(the, resultTable, resultList, value, 0, 0);
    else
      fxSetEntry(the, resultTable, resultList, value, C_NULL, 0);
  }
  fxResizeEntries(the, resultTable, resultList);
  fxPurgeEntries(the, resultList);
  the->stack = stack;
}

void fx_Set_prototype_union(txMachine* the)
{
  txSlot* stack = the->stack;
  txSlot* instance = fxCheckSetInstance(the, mxThis, XS_IMMUTABLE);
  txSlot* table = instance->next;
  txSlot* list = table->next;
  txSlot *otherKeys, *resultTable, *resultList, *iterator, *next, *value;
  txSlot *other = fxCheckSetRecord(the, C_NULL, C_NULL, &otherKeys);
  fxNewSetResult(the, table, list, &resultTable, &resultList);
  fxSetRecordKeys(the, other, otherKeys, &iterator, &next, &value);
  while (fxIteratorNext(the, iterator, next, value)) {
    fxCanonicalizeKeyedCollectionKey(value);
    fxSetEntry(the, resultTable, resultList, value, C_NULL, 0);
  }
  the->stack = stack;
}

void fx_Set_prototype_values(txMachine* the)
{
  fxCheckSetInstance(the, mxThis, XS_IMMUTABLE);
  fxNewSetIteratorInstance(the, mxThis, 1);
}

txSlot* fxNewSetIteratorInstance(txMachine* the, txSlot* iterable, txInteger kind) 
{
  txSlot* instance;
  txSlot* property;
  mxPush(mxSetIteratorPrototype);
  instance = fxNewIteratorInstance(the, iterable, mxID(_Set));
  property = fxLastProperty(the, instance);
  property->kind = XS_LIST_KIND;
  property->value.list.first = C_NULL;
  property->value.list.last = C_NULL;
  property = fxNextIntegerProperty(the, property, kind, XS_NO_ID, XS_INTERNAL_FLAG);
  mxPullSlot(mxResult);
  return instance;
}

void fx_SetIterator_prototype_next(txMachine* the)
{
  txSlot* iterator = fxCheckIteratorInstance(the, mxThis, mxID(_Set));
  txSlot* result = iterator->next;
  txSlot* iterable = result->next;
  mxResult->kind = result->kind;
  mxResult->value = result->value;
  result = fxCheckIteratorResult(the, result);
  if (result->next->value.boolean == 0) {
    txSlot* list = iterable->next;
    txInteger kind = list->next->value.integer;
    txSlot* value = list->value.list.first;
    if (value)
      value = value->next;
    else
      value = iterable->value.reference->next->next->value.list.first;
    while (value && (value->flag & XS_DONT_ENUM_FLAG))
      value = value->next;
    if (value) {
      if (kind == 2) {
        mxPushSlot(value);
        mxPushSlot(value);
        fxConstructArrayEntry(the, result);
      }
      else {
        result->kind = value->kind;
        result->value = value->value;
      }
      list->value.list.first = value;
    }
    else {
      result->kind = XS_UNDEFINED_KIND;
      result->next->value.boolean = 1;
      list->value.list.first = C_NULL;
    }
  }
}

txSlot* fxCanonicalizeKeyedCollectionKey(txSlot* key)
{
  if ((key->kind == XS_NUMBER_KIND) && (key->value.number == 0)) { \
    key->kind = XS_INTEGER_KIND; \
    key->value.integer = 0; \
  }
  return key;
}

void fxClearEntries(txMachine* the, txSlot* table, txSlot* list, txBoolean paired)
{
  txSlot* slot = list->value.list.first;
  while (slot) {
    slot->flag = XS_DONT_ENUM_FLAG;
    slot->kind = XS_UNDEFINED_KIND;
    slot = slot->next;
  }
  c_memset(table->value.table.address, 0, table->value.table.length * sizeof(txSlot*));
  list->next->value.integer = 0;
  fxResizeEntries(the, table, list);
  fxPurgeEntries(the, list);
}

txBoolean fxDeleteEntry(txMachine* the, txSlot* table, txSlot* list, txSlot* key, txBoolean paired, txBoolean fit) 
{
  txSlot* info = list->next;
  txU4 sum = fxSumEntry(the, key);
  txU4 index = sum & (table->value.table.length - 1);
  txSlot** address = &(table->value.table.address[index]);
  txSlot* entry;
  txSlot* first;
  txSlot* last;
  while ((entry = *address)) {
    if (entry->value.entry.sum == sum) {
      first = entry->value.entry.slot;
      if (fxTestEntry(the, first, key)) {
        *address = entry->next;
        entry->next = C_NULL;
        first->flag = XS_DONT_ENUM_FLAG;
        first->kind = XS_UNDEFINED_KIND;
        if (paired) {
          last = first->next;
          last->flag = XS_DONT_ENUM_FLAG;
          last->kind = XS_UNDEFINED_KIND;
        }
        info->value.integer--;
        if (fit) {
          fxResizeEntries(the, table, list);
          fxPurgeEntries(the, list);
        }
        return 1;
      }
    }
    address = &entry->next;
  }
  return 0;
}

txSlot* fxGetEntry(txMachine* the, txSlot* table, txSlot* slot) 
{
  txU4 sum = fxSumEntry(the, slot);
  txU4 index = sum & (table->value.table.length - 1);
  txSlot* entry = table->value.table.address[index];
  txSlot* result;
  while (entry) {
    if (entry->value.entry.sum == sum) {
      result = entry->value.entry.slot;
      if (fxTestEntry(the, result, slot))
        return result;
    }
    entry = entry->next;
  }
  return C_NULL;
}

void fxPurgeEntries(txMachine* the, txSlot* list) 
{
  txSlot* former = C_NULL;
  txSlot** address = &(list->value.list.first);
  txSlot* slot;
  while ((slot = *address)) {
    if (slot->flag & XS_DONT_ENUM_FLAG) {
      *address = slot->next;
    }
    else {
      former = slot;
      address = &slot->next;
    }
  }
  list->value.list.last = former;
}

void fxResizeEntries(txMachine* the, txSlot* table, txSlot* list) 
{
  txSize size = list->next->value.integer;
  txSize formerLength = table->value.table.length;
  txSize currentLength = formerLength;
  txSize high = mxTableThreshold(formerLength);
  txSize low = mxTableThreshold(formerLength) >> 1;
  if (high < size) {
    currentLength = formerLength << 1;
    if (currentLength > mxTableMaxLength)
      currentLength = mxTableMaxLength;
  }
  else if (low >= size) {
    currentLength = formerLength >> 1;
    if (currentLength < mxTableMinLength)
      currentLength = mxTableMinLength;
  }
  if (formerLength != currentLength) {
    txSlot** currentAddress = (txSlot**)fxNewChunk(the, currentLength * sizeof(txSlot*));
    if (currentAddress) {
      txSlot** formerAddress = table->value.table.address;

            txSize currentMask = currentLength - 1;
      c_memset(currentAddress, 0, currentLength * sizeof(txSlot*));
      while (formerLength) {
        txSlot* entry;
        while ((entry = *formerAddress)) {
          txU4 index = entry->value.entry.sum & currentMask;
           *formerAddress = entry->next;
          entry->next = currentAddress[index];
          currentAddress[index] = entry;
        }
        formerLength--;
        formerAddress++;
      }
      table->value.table.address = currentAddress;
      table->value.table.length = currentLength;
    }
  }
//  {
//    txSize holes = 0;
//    txSize collisions = 0;
//    txSize i =  0;
//    while (i < table->value.table.length) {
//      txSize j = 0;
//      txSlot* entry = table->value.table.address[i];
//      while (entry) {
//        j++;
//        entry = entry->next;
//      }
//      if (j == 0)
//        holes++;
//      else if (collisions < j)
//        collisions = j;
//      i++;
//    }
//    fprintf(stderr, "# size %d capacity %d holes %d collisions <%d\n", size, table->value.table.length, holes, collisions);
//  }
}

void fxSetEntry(txMachine* the, txSlot* table, txSlot* list, txSlot* key, txSlot* pair, txBoolean get) 
{
  txU4 sum = fxSumEntry(the, key);
  txU4 index = sum & (table->value.table.length - 1);
  txSlot** address = &(table->value.table.address[index]);
  txSlot* entry = *address;
  txSlot* first;
  txSlot* last;
  while (entry) {
    if (entry->value.entry.sum == sum) {
      first = entry->value.entry.slot;
      if (fxTestEntry(the, first, key)) {
        if (pair) {
          last = first->next;
          if (get) {
            pair->kind = last->kind;
            pair->value = last->value;
          }
          else {
            last->kind = pair->kind;
            last->value = pair->value;
          }
        }
        return;
      }
    }
    entry = entry->next;
  }
  first = fxNewSlot(the);
  first->kind = key->kind;
  first->value = key->value;
  mxPushClosure(first);
  if (pair) {
    first->next = last = fxNewSlot(the);
    last->kind = pair->kind;
    last->value = pair->value;
    mxPushClosure(last);
  }
  entry = fxNewSlot(the);
  address = &(table->value.table.address[index]);
  entry->next = *address;
  entry->kind = XS_ENTRY_KIND;
  entry->value.entry.slot = first;
  entry->value.entry.sum = sum;
  *address = entry;
  if (list->value.list.last)
    list->value.list.last->next = first;
  else
    list->value.list.first = first;
  if (pair)
    list->value.list.last = last;
  else
    list->value.list.last = first;
  if (pair)
    mxPop();
  mxPop();
  list->next->value.integer++;
  fxResizeEntries(the, table, list);
}

txU4 fxSumEntry(txMachine* the, txSlot* slot) 
{
  txU1 kind = slot->kind;
  txU8 sum;
  
  if ((XS_STRING_KIND == kind) || (XS_STRING_X_KIND == kind)) {
    // Dan Bernstein: http://www.cse.yorku.ca/~oz/hash.html
    txU1 *string = (txU1*)slot->value.string;
    sum = 5381;
    while ((kind = c_read8(string++))) {
      sum = ((sum << 5) + sum) + kind;
    }
  }
  else {
    if (XS_REFERENCE_KIND == kind) {
      sum = (txU8)(((uintptr_t)slot->value.reference) / sizeof(txSlot));
    }
    else if (XS_INTEGER_KIND == kind) {
      fxToNumber(the, slot);
      sum = *((txU8*)&slot->value.number);
    }
    else if (XS_NUMBER_KIND == kind) {
      if (slot->value.number == 0) {
        sum = slot->value.number = 0;
      }
      else {
        if (c_isnan(slot->value.number)) {
        #if mxCanonicalNaN
          slot->value.number = *gxCanonicalNaN64;
        #else       
          slot->value.number = C_NAN;
        #endif
        }
        sum = *((txU8*)&slot->value.number);
      }
    }
    else if ((XS_BIGINT_KIND == kind) || (XS_BIGINT_X_KIND == kind)) {
      sum = gxTypeBigInt.toBigUint64(the, slot);
    }
    else if (XS_SYMBOL_KIND == kind) {
      sum = slot->value.symbol;
    }
    else if (XS_BOOLEAN_KIND == kind) {
      sum = slot->value.boolean;
    }
    else {
      sum = 0;
    }
    // Thomas Wang: http://web.archive.org/web/20071223173210/http://www.concentric.net/~Ttwang/tech/inthash.htm
    sum = (~sum) + (sum << 18); // sum = (sum << 18) - sum - 1;
    sum = sum ^ (sum >> 31);
    sum = sum * 21; // sum = (sum + (sum << 2)) + (sum << 4);
    sum = sum ^ (sum >> 11);
    sum = sum + (sum << 6);
    sum = sum ^ (sum >> 22);
  }
  sum &= 0xFFFFFFFF;
  return (txU4)sum;
}

txBoolean fxTestEntry(txMachine* the, txSlot* a, txSlot* b)
{ 
  txBoolean result = 0;
  if (a->kind == b->kind) {
    if ((XS_UNDEFINED_KIND == a->kind) || (XS_NULL_KIND == a->kind))
      result = 1;
    else if (XS_BOOLEAN_KIND == a->kind)
      result = a->value.boolean == b->value.boolean;
    else if (XS_INTEGER_KIND == a->kind)
      result = a->value.integer == b->value.integer;
        else if (XS_NUMBER_KIND == a->kind)
      result = ((c_isnan(a->value.number) && c_isnan(b->value.number)) || (a->value.number == b->value.number));
    else if ((XS_STRING_KIND == a->kind) || (XS_STRING_X_KIND == a->kind))
      result = c_strcmp(a->value.string, b->value.string) == 0;
    else if (XS_SYMBOL_KIND == a->kind)
      result = a->value.symbol == b->value.symbol;
    else if ((XS_BIGINT_KIND == a->kind) || (XS_BIGINT_X_KIND == a->kind))
      result = gxTypeBigInt.compare(the, 0, 1, 0, a, b);
    else if (XS_REFERENCE_KIND == a->kind)
      result = a->value.reference == b->value.reference;
  }
  else if ((XS_INTEGER_KIND == a->kind) && (XS_NUMBER_KIND == b->kind))
    result = (!c_isnan(b->value.number)) && ((txNumber)(a->value.integer) == b->value.number);
  else if ((XS_NUMBER_KIND == a->kind) && (XS_INTEGER_KIND == b->kind))
    result = (!c_isnan(a->value.number)) && (a->value.number == (txNumber)(b->value.integer));
  else if ((XS_STRING_KIND == a->kind) && (XS_STRING_X_KIND == b->kind))
    result = c_strcmp(a->value.string, b->value.string) == 0;
  else if ((XS_STRING_X_KIND == a->kind) && (XS_STRING_KIND == b->kind))
    result = c_strcmp(a->value.string, b->value.string) == 0;
  else if ((XS_BIGINT_KIND == a->kind) && (XS_BIGINT_X_KIND == b->kind))
    result = gxTypeBigInt.compare(the, 0, 1, 0, a, b);
  else if ((XS_BIGINT_X_KIND == a->kind) && (XS_BIGINT_KIND == b->kind))
    result = gxTypeBigInt.compare(the, 0, 1, 0, a, b);
  return result;
}

txSlot* fxCanBeHeldWeakly(txMachine* the, txSlot* slot)
{
  if (slot->kind == XS_REFERENCE_KIND)
    slot = slot->value.reference;
#if mxKeysGarbageCollection
  else if (slot->kind == XS_SYMBOL_KIND) {
    slot = fxGetKey(the, slot->value.symbol);
    if (slot->kind == XS_REFERENCE_KIND)
      slot = slot->value.reference;
    else
      slot = C_NULL;
  }
#endif
  else
    slot = C_NULL;
  return slot;
}

txSlot* fxCheckWeakMapInstance(txMachine* the, txSlot* slot, txBoolean mutable)
{
  if (slot->kind == XS_REFERENCE_KIND) {
    txSlot* instance = slot->value.reference;
    if (((slot = instance->next)) && (slot->flag & XS_INTERNAL_FLAG) && (slot->kind == XS_WEAK_MAP_KIND) && (instance != mxWeakMapPrototype.value.reference)) {
      if (mutable && (slot->flag &  XS_DONT_SET_FLAG))
        mxTypeError("this: read-only WeakMap instance");
      return instance;
    }
  }
  mxTypeError("this: not a WeakMap instance");
  return C_NULL;
}

txSlot* fxCheckWeakMapKey(txMachine* the, txBoolean mutable)
{
  if (mxArgc > 0) {
    txSlot* slot = fxCanBeHeldWeakly(the, mxArgv(0));
    if (slot && mutable && (slot->flag & XS_MARK_FLAG))
      mxTypeError("key: read-only");
    return slot;
  }
  return C_NULL;
}

txSlot* fxNewWeakMapInstance(txMachine* the)
{
  txSlot* map;
  txSlot* list;
  map = fxNewSlot(the);
  map->kind = XS_INSTANCE_KIND;
  map->value.instance.garbage = C_NULL;
  map->value.instance.prototype = the->stack->value.reference;
  the->stack->kind = XS_REFERENCE_KIND;
  the->stack->value.reference = map;
  /* LIST */
  list = map->next = fxNewSlot(the);
  list->flag = XS_INTERNAL_FLAG;
  list->kind = XS_WEAK_MAP_KIND;
  list->value.weakList.first = C_NULL;
  list->value.weakList.link = the->firstWeakListLink;
  the->firstWeakListLink = list;
  return map;
}

void fx_WeakMap(txMachine* the)
{
  txSlot *function, *iterable, *iterator, *next, *value;
  if (!mxHasTarget)
    mxTypeError("call: WeakMap");
  mxPushSlot(mxTarget);
  fxGetPrototypeFromConstructor(the, &mxWeakMapPrototype);
  fxNewWeakMapInstance(the);
  mxPullSlot(mxResult);
  if (mxArgc < 1)
    return;
  iterable = mxArgv(0);
  if ((iterable->kind == XS_UNDEFINED_KIND) || (iterable->kind == XS_NULL_KIND))
    return;
  mxPushSlot(mxResult);
  mxGetID(mxID(_set)); 
  function = the->stack;  
  if (!fxIsCallable(the, function))  
    mxTypeError("result.set: not a function");
  mxTemporary(iterator);
  mxTemporary(next);
  fxGetIterator(the, iterable, iterator, next, 0);  
  mxTemporary(value);
  while (fxIteratorNext(the, iterator, next, value)) {
    mxTry(the) {
      mxPushSlot(mxResult);
      mxPushSlot(function);
      mxCall();
      if (value->kind != XS_REFERENCE_KIND)
        mxTypeError("item: not an object");
      mxPushSlot(value);
      mxGetIndex(0);
      mxPushSlot(value);
      mxGetIndex(1);
      mxRunCount(2);
      mxPop();
    }
    mxCatch(the) {
      fxIteratorReturn(the, iterator, 1);
      fxJump(the);
    }
  }
}

void fx_WeakMap_prototype_delete(txMachine* the)
{
  txSlot* instance = fxCheckWeakMapInstance(the, mxThis, XS_MUTABLE);
  txSlot* key = fxCheckWeakMapKey(the, XS_MUTABLE);
  mxResult->value.boolean = (key) ? fxDeleteWeakEntry(the, instance->next, key) : 0;
  mxResult->kind = XS_BOOLEAN_KIND;
}

void fx_WeakMap_prototype_get(txMachine* the)
{
  txSlot* instance = fxCheckWeakMapInstance(the, mxThis, XS_IMMUTABLE);
  txSlot* key = fxCheckWeakMapKey(the, XS_IMMUTABLE);
  txSlot* result = (key) ? fxGetWeakEntry(the, instance->next, key) : C_NULL;
  if (result) {
    txSlot* value = result->value.weakEntry.value;
    mxResult->kind = value->kind;
    mxResult->value = value->value;
  }
}

void fx_WeakMap_prototype_getOrInsert(txMachine* the)
{
  txSlot* instance = fxCheckWeakMapInstance(the, mxThis, XS_MUTABLE);
  txSlot* key = fxCheckWeakMapKey(the, XS_MUTABLE);
  if (!key)
    mxTypeError("key: not an object");
  *mxResult = (mxArgc > 1) ? *mxArgv(1) : mxUndefined;
  fxSetWeakEntry(the, instance->next, key, mxResult, 1);
}

void fx_WeakMap_prototype_getOrInsertComputed(txMachine* the)
{
  txSlot* instance = fxCheckWeakMapInstance(the, mxThis, XS_MUTABLE);
  txSlot* key = fxCheckWeakMapKey(the, XS_MUTABLE);
  txSlot* function;
  txSlot* result;
  if (!key)
    mxTypeError("key: not an object");
  function = fxArgToCallback(the, 1);
  result = fxGetWeakEntry(the, instance->next, key);
  if (result) {
    txSlot* value = result->value.weakEntry.value;
    mxResult->kind = value->kind;
    mxResult->value = value->value;
    return;
  }
  mxPushUndefined();
  mxPushSlot(function);
  mxCall();
  if (key->next && (key->next->flag & XS_INTERNAL_FLAG) && (key->next->kind == XS_SYMBOL_KIND))
    mxPushSlot(key->next);
  else
    mxPushReference(key);
  mxRunCount(1);
  mxPullSlot(mxResult);
  fxSetWeakEntry(the, instance->next, key, mxResult, 0);
}

void fx_WeakMap_prototype_has(txMachine* the)
{
  txSlot* instance = fxCheckWeakMapInstance(the, mxThis, XS_IMMUTABLE);
  txSlot* key = fxCheckWeakMapKey(the, XS_IMMUTABLE);
  txSlot* result = (key) ? fxGetWeakEntry(the, instance->next, key) : C_NULL;
  mxResult->kind = XS_BOOLEAN_KIND;
  mxResult->value.boolean = (result) ? 1 : 0;
}

void fx_WeakMap_prototype_set(txMachine* the)
{
  txSlot* instance = fxCheckWeakMapInstance(the, mxThis, XS_MUTABLE);
  txSlot* key = fxCheckWeakMapKey(the, XS_MUTABLE);
  if (!key)
    mxTypeError("key: not an object");
  fxSetWeakEntry(the, instance->next, key, (mxArgc > 1) ? mxArgv(1) : &mxUndefined, 0);
  *mxResult = *mxThis;
}

txSlot* fxCheckWeakSetInstance(txMachine* the, txSlot* slot, txBoolean mutable)
{
  if (slot->kind == XS_REFERENCE_KIND) {
    txSlot* instance = slot->value.reference;
    if (((slot = instance->next)) && (slot->flag & XS_INTERNAL_FLAG) && (slot->kind == XS_WEAK_SET_KIND) && (instance != mxWeakSetPrototype.value.reference)) {
      if (mutable && (slot->flag & XS_DONT_SET_FLAG))
        mxTypeError("this: read-only WeakSet instance");
      return instance;
    }
  }
  mxTypeError("this: not a WeakSet instance");
  return C_NULL;
}

txSlot* fxCheckWeakSetValue(txMachine* the, txBoolean mutable)
{
  if (mxArgc > 0) {
    txSlot* slot = fxCanBeHeldWeakly(the, mxArgv(0));
    if (slot && mutable && (slot->flag & XS_MARK_FLAG))
      mxTypeError("value: read-only");
    return slot;
  }
  return C_NULL;
}

txSlot* fxNewWeakSetInstance(txMachine* the)
{
  txSlot* set;
  txSlot* list;
  set = fxNewSlot(the);
  set->kind = XS_INSTANCE_KIND;
  set->value.instance.garbage = C_NULL;
  set->value.instance.prototype = the->stack->value.reference;
  the->stack->kind = XS_REFERENCE_KIND;
  the->stack->value.reference = set;
  /* LIST */
  list = set->next = fxNewSlot(the);
  list->flag = XS_INTERNAL_FLAG;
  list->kind = XS_WEAK_SET_KIND;
  list->value.weakList.first = C_NULL;
  list->value.weakList.link = the->firstWeakListLink;
  the->firstWeakListLink = list;
  return set;
}

void fx_WeakSet(txMachine* the)
{
  txSlot *function, *iterable, *iterator, *next, *value;
  if (!mxHasTarget)
    mxTypeError("call: WeakSet");
  mxPushSlot(mxTarget);
  fxGetPrototypeFromConstructor(the, &mxWeakSetPrototype);
  fxNewWeakSetInstance(the);
  mxPullSlot(mxResult);
  if (mxArgc < 1)
    return;
  iterable = mxArgv(0);
  if ((iterable->kind == XS_UNDEFINED_KIND) || (iterable->kind == XS_NULL_KIND))
    return;
  mxPushSlot(mxResult);
  mxGetID(mxID(_add)); 
  function = the->stack;  
  if (!fxIsCallable(the, function))  
    mxTypeError("result.add: not a function");
  mxTemporary(iterator);
  mxTemporary(next);
  fxGetIterator(the, iterable, iterator, next, 0);  
  mxTemporary(value);
  while (fxIteratorNext(the, iterator, next, value)) {
    mxTry(the) {
      mxPushSlot(mxResult);
      mxPushSlot(function);
      mxCall();
      mxPushSlot(value);
      mxRunCount(1);
      mxPop();
    }
    mxCatch(the) {
      fxIteratorReturn(the, iterator, 1);
      fxJump(the);
    }
  }
}

void fx_WeakSet_prototype_add(txMachine* the)
{
  txSlot* instance = fxCheckWeakSetInstance(the, mxThis, XS_MUTABLE);
  txSlot* value = fxCheckWeakSetValue(the, XS_MUTABLE);
  if (!value)
    mxTypeError("value: not an object");
  fxSetWeakEntry(the, instance->next, value, &mxUndefined, 0);
  *mxResult = *mxThis;
}

void fx_WeakSet_prototype_has(txMachine* the)
{
  txSlot* instance = fxCheckWeakSetInstance(the, mxThis, XS_IMMUTABLE);
  txSlot* value = fxCheckWeakSetValue(the, XS_IMMUTABLE);
  txSlot* result = (value) ? fxGetWeakEntry(the, instance->next, value) : C_NULL;
  mxResult->kind = XS_BOOLEAN_KIND;
  mxResult->value.boolean = (result) ? 1 : 0;
}

void fx_WeakSet_prototype_delete(txMachine* the)
{
  txSlot* instance = fxCheckWeakSetInstance(the, mxThis, XS_MUTABLE);
  txSlot* value = fxCheckWeakSetValue(the, XS_MUTABLE);
  mxResult->value.boolean = (value) ? fxDeleteWeakEntry(the, instance->next, value) : 0;
  mxResult->kind = XS_BOOLEAN_KIND;
}

txBoolean fxDeleteWeakEntry(txMachine* the, txSlot* list, txSlot* key) 
{
  txSlot* slot = (key->flag & XS_EXOTIC_FLAG) ? key->next : key;
  txSlot** address = &slot->next;
  while ((slot = *address)) {
    if (!(slot->flag & XS_INTERNAL_FLAG))
      break;
    if ((slot->kind == XS_WEAK_ENTRY_KIND) && (slot->value.weakEntry.check == list)) {
      slot->value.weakEntry.value->kind = XS_UNINITIALIZED_KIND;
      *address = slot->next;
      return 1;
    }      
    address = &slot->next;
  }
  return 0;
}

txSlot* fxGetWeakEntry(txMachine* the, txSlot* list, txSlot* key) 
{
  txSlot* slot = (key->flag & XS_EXOTIC_FLAG) ? key->next : key;
    slot = slot->next;
  while (slot) {
    if (!(slot->flag & XS_INTERNAL_FLAG))
      break;
    if ((slot->kind == XS_WEAK_ENTRY_KIND) && (slot->value.weakEntry.check == list))
      return slot;
    slot = slot->next;
  }
  return C_NULL;
}

void fxSetWeakEntry(txMachine* the, txSlot* list, txSlot* key, txSlot* value, txBoolean get) 
{
  txSlot* slot = (key->flag & XS_EXOTIC_FLAG) ? key->next : key;
  txSlot** address = &slot->next;
  txSlot* keyEntry;
  txSlot* listEntry;
  txSlot* closure;
  while ((slot = *address)) {
    if (!(slot->flag & XS_INTERNAL_FLAG))
      break;
    if ((slot->kind == XS_WEAK_ENTRY_KIND) && (slot->value.weakEntry.check == list)) {
      slot = slot->value.weakEntry.value;
      if (get) {
        value->kind = slot->kind;
        value->value = slot->value;
      }
      else {
        slot->kind = value->kind;
        slot->value = value->value;
      }
      return;
    }      
    address = &slot->next;
  }
  
  keyEntry = fxNewSlot(the);
  mxPushClosure(keyEntry);
  listEntry = fxNewSlot(the);
  mxPushClosure(listEntry);
  closure = fxNewSlot(the);
  closure->kind = value->kind;
  closure->value = value->value;
  
  slot = (key->flag & XS_EXOTIC_FLAG) ? key->next : key;
  address = &slot->next;
  while ((slot = *address)) {
    if (!(slot->flag & XS_INTERNAL_FLAG))
      break;
    address = &slot->next;
  }
  
  keyEntry->next = *address;
  keyEntry->flag = XS_INTERNAL_FLAG;
  keyEntry->kind = XS_WEAK_ENTRY_KIND;
  keyEntry->value.weakEntry.check = list;
  keyEntry->value.weakEntry.value = closure;
  *address = keyEntry;
  
  listEntry->next = list->value.weakList.first;
  listEntry->flag = XS_INTERNAL_FLAG;
  listEntry->kind = XS_WEAK_ENTRY_KIND;
  listEntry->value.weakEntry.check = key;
  listEntry->value.weakEntry.value = closure;
  list->value.weakList.first = listEntry;
  
  mxPop();
  mxPop();
}

void fxKeepDuringJobs(txMachine* the, txSlot* target)
{
  txSlot* instance = mxDuringJobs.value.reference;
  txSlot** address = &(instance->next);
  txSlot* slot;
  while ((slot = *address)) {
    if (slot->value.reference == target)
      return;
    address = &(slot->next);
  }
  *address = slot = fxNewSlot(the);
  slot->value.reference = target;
  slot->kind = XS_REFERENCE_KIND;
}

txSlot* fxCheckWeakRefInstance(txMachine* the, txSlot* slot)
{
  if (slot->kind == XS_REFERENCE_KIND) {
    txSlot* instance = slot->value.reference;
    if (((slot = instance->next)) && (slot->flag & XS_INTERNAL_FLAG) && (slot->kind == XS_WEAK_REF_KIND))
      return instance;
  }
  mxTypeError("this is no WeakRef instance");
  return C_NULL;
}

txSlot* fxNewWeakRefInstance(txMachine* the)
{
  txSlot* slot;
  txSlot* instance = fxNewSlot(the);
  instance->kind = XS_INSTANCE_KIND;
  instance->value.instance.garbage = C_NULL;
  instance->value.instance.prototype = the->stack->value.reference;
  the->stack->kind = XS_REFERENCE_KIND;
  the->stack->value.reference = instance;
  slot = instance->next = fxNewSlot(the);
  slot->flag = XS_INTERNAL_FLAG;
  slot->kind = XS_WEAK_REF_KIND;
  slot->value.weakRef.target = C_NULL;
  slot->value.weakRef.link = C_NULL;
  return instance;
}

void fx_WeakRef(txMachine* the)
{
  txSlot* target;
  txSlot* instance;
  if (!mxHasTarget)
    mxTypeError("call: WeakRef");
  if (mxArgc < 1)
    mxTypeError("no target");
  target = fxCanBeHeldWeakly(the, mxArgv(0));
  if (!target)
    mxTypeError("target: not an object");
  mxPushSlot(mxTarget);
  fxGetPrototypeFromConstructor(the, &mxWeakRefPrototype);
  instance = fxNewWeakRefInstance(the);
  mxPullSlot(mxResult);
  fxKeepDuringJobs(the, target);
  instance->next->value.weakRef.target = target;
}

void fx_WeakRef_prototype_deref(txMachine* the)
{
  txSlot* instance = fxCheckWeakRefInstance(the, mxThis);
  txSlot* target = instance->next->value.weakRef.target;
  if (target) {
    txSlot* property = target->next;
    if (property && (property->flag & XS_INTERNAL_FLAG) && (property->kind == XS_SYMBOL_KIND)) {
      mxResult->value.symbol = property->value.symbol;
      mxResult->kind = XS_SYMBOL_KIND;
    }
    else {
      mxResult->value.reference = target;
      mxResult->kind = XS_REFERENCE_KIND;
    }
    fxKeepDuringJobs(the, target);
  }
}

txSlot* fxCheckFinalizationRegistryInstance(txMachine* the, txSlot* slot)
{
  if (slot->kind == XS_REFERENCE_KIND) {
    txSlot* instance = slot->value.reference;
    if (((slot = instance->next)) && (slot->flag & XS_INTERNAL_FLAG) && (slot->kind == XS_CLOSURE_KIND) && (slot->value.closure->kind == XS_FINALIZATION_REGISTRY_KIND)) {
      if (slot->flag & XS_MARK_FLAG)
        mxTypeError("this: read-only FinalizationRegistry instance");
      return instance;
    }
  }
  mxTypeError("this: not a FinalizationRegistry instance");
  return C_NULL;
}

void fx_FinalizationRegistry(txMachine* the)
{
  txSlot* callback;
  txSlot* instance;
  txSlot* property;
  txSlot* registry;
  txSlot* slot;
  if (!mxHasTarget)
    mxTypeError("call: FinalizationRegistry");
  if (mxArgc < 1)
    mxTypeError("no callback");
  callback = mxArgv(0);
  if (!fxIsCallable(the, callback))
    mxTypeError("callback: not a function");
  mxPushSlot(mxTarget);
  fxGetPrototypeFromConstructor(the, &mxFinalizationRegistryPrototype);
  instance = fxNewSlot(the);
  instance->kind = XS_INSTANCE_KIND;
  instance->value.instance.garbage = C_NULL;
  instance->value.instance.prototype = the->stack->value.reference;
  the->stack->kind = XS_REFERENCE_KIND;
  the->stack->value.reference = instance;
  mxPullSlot(mxResult);
  property = instance->next = fxNewSlot(the);
  property->flag = XS_INTERNAL_FLAG;
  property->kind = XS_CLOSURE_KIND;
  property->value.closure = C_NULL;
  registry = fxNewSlot(the);
  registry->kind = XS_FINALIZATION_REGISTRY_KIND;
  registry->value.finalizationRegistry.callback = C_NULL;
  registry->value.finalizationRegistry.flags = XS_NO_FLAG;
  property->value.closure = registry;
  slot = fxNewSlot(the);
  slot->kind = callback->kind;
  slot->value = callback->value;
  registry->value.finalizationRegistry.callback = slot;
}


#if 0
// removed from FinalizationRegistry specification
void fx_FinalizationRegistry_prototype_cleanupSome(txMachine* the)
{
  txSlot* instance;
  txSlot* registry;
  txSlot* callback = C_NULL;
  txSlot** address;
  txSlot* slot;
  if (!mxIsReference(mxThis))
    mxTypeError("this: not an object");
  instance = fxCheckFinalizationRegistryInstance(the, mxThis);
  registry = instance->next->value.closure;
  if (mxArgc > 0) {
    callback = mxArgv(0);
    if (mxIsUndefined(callback))
      callback = C_NULL;
    else if (!fxIsCallable(the, callback))
      mxTypeError("callback: not a function");
  }
  fx_FinalizationRegistryCleanup(the, registry, callback);
  callback = registry->value.finalizationRegistry.callback;
  if (callback->next == C_NULL) {
    address = &(mxFinalizationRegistries.value.reference->next);
    while ((slot = *address)) {
      if (slot->value.closure == registry) {
        *address = slot->next;
        return;
      }
      address = &(slot->next);
    }
  }
}
#endif

void fx_FinalizationRegistry_prototype_register(txMachine* the)
{
  txSlot* instance;
  txSlot* registry;
  txSlot* target;
  txSlot* token = C_NULL;
  txSlot* callback;
  txSlot** address;
  txSlot* slot;
  if (!mxIsReference(mxThis))
    mxTypeError("this: not an object");
  instance = fxCheckFinalizationRegistryInstance(the, mxThis);
  registry = instance->next->value.closure;
  if (mxArgc < 1)
    mxTypeError("no target");
  target = fxCanBeHeldWeakly(the, mxArgv(0));
  if (!target)
    mxTypeError("target: not an object");
  if (mxArgc > 1) {
    if (fxIsSameValue(the, mxArgv(0), mxArgv(1), 1))
      mxTypeError("target and holdings are the same");
  }
  if (mxArgc > 2) {
    token = mxArgv(2);
    if (mxIsUndefined(token))
      token = C_NULL;
    else {
      token = fxCanBeHeldWeakly(the, token);
      if (!token)
        mxTypeError("token: not an object");
    }
  }
  callback = registry->value.finalizationRegistry.callback;
  address = &(callback->next);
  while ((slot = *address))
    address = &(slot->next);
  slot = *address = fxNewSlot(the);
  if (mxArgc > 1) {
    slot->kind = mxArgv(1)->kind;
    slot->value = mxArgv(1)->value;
  }
  slot = slot->next = fxNewSlot(the);
  slot->kind = XS_FINALIZATION_CELL_KIND;
  slot->value.finalizationCell.target = target;
  slot->value.finalizationCell.token = token;
  
  address = &(mxFinalizationRegistries.value.reference->next);
  while ((slot = *address)) {
    if (slot->value.closure == registry)
      return;
    address = &(slot->next);
  }
  slot = *address = fxNewSlot(the);
  slot->kind = XS_CLOSURE_KIND;
  slot->value.closure = registry;
}  

void fx_FinalizationRegistry_prototype_unregister(txMachine* the)
{
  txSlot* instance;
  txSlot* token;
  txSlot* registry;
  txSlot* callback;
  txSlot** address;
  txSlot* slot;
  if (!mxIsReference(mxThis))
    mxTypeError("this: not an object");
  instance = fxCheckFinalizationRegistryInstance(the, mxThis);
  if (mxArgc < 1)
    mxTypeError("no token");
  token = fxCanBeHeldWeakly(the, mxArgv(0));
  if (!token)
    mxTypeError("token: not an object");
  mxResult->kind = XS_BOOLEAN_KIND;
  mxResult->value.boolean = 0;
  registry = instance->next->value.closure;
  callback = registry->value.finalizationRegistry.callback;
  address = &(callback->next);
  while ((slot = *address)) {
    slot = slot->next;
    if (slot->value.finalizationCell.token && fxIsSameInstance(the, slot->value.finalizationCell.token, token)) {
      *address = slot->next;
      mxResult->value.boolean = 1;
    }
    else
      address = &(slot->next);
  }
  if (callback->next == C_NULL) {
    address = &(mxFinalizationRegistries.value.reference->next);
    while ((slot = *address)) {
      if (slot->value.closure == registry) {
        *address = slot->next;
        return;
      }
      address = &(slot->next);
    }
  }
}

void fx_FinalizationRegistryCleanup(txMachine* the, txSlot* registry, txSlot* callback)
{
  txSlot* slot;
  txUnsigned flags;
  txSlot** address;
  txSlot* value;

  if (!(registry->value.finalizationRegistry.flags & XS_FINALIZATION_REGISTRY_CHANGED))
    return;
    
  slot = registry->value.finalizationRegistry.callback->next;
  flags = 0;
  while (slot) {
    slot = slot->next;
    if (slot->value.finalizationCell.target == C_NULL) {
      flags = 1;
      break;
    }
    slot = slot->next;
  }
  if (!flags)
    return;
  if (!callback)
    callback = registry->value.finalizationRegistry.callback;
  flags = registry->value.finalizationRegistry.flags;
  {
    mxTry(the) {
      address = &(registry->value.finalizationRegistry.callback->next);
      while ((value = *address)) {
        slot = value->next;
        if (slot->value.finalizationCell.target == C_NULL) {
          *address = slot->next;
          mxPushUndefined();
          mxPushSlot(callback);
          mxCall();
          mxPushSlot(value);
          mxRunCount(1);
          mxPop();
        }
        else
          address = &(slot->next);
      }
      registry->value.finalizationRegistry.flags = flags;
    }
    mxCatch(the) {
      registry->value.finalizationRegistry.flags = flags;
      fxJump(the);
    }
  }
  
  slot = registry->value.finalizationRegistry.callback->next;
  while (slot) {
    slot = slot->next;
    if (slot->value.finalizationCell.target == C_NULL)
      break;
    slot = slot->next;
  }
  if (!slot)
    registry->value.finalizationRegistry.flags &= ~XS_FINALIZATION_REGISTRY_CHANGED;
}

void fxCleanupFinalizationRegistries(txMachine* the)
{
  txSlot** address = &(mxFinalizationRegistries.value.reference->next);
  txSlot* closure;
  while ((closure = *address)) {
    txSlot* registry = closure->value.closure;
    if (registry->value.finalizationRegistry.flags & XS_FINALIZATION_REGISTRY_CHANGED) {
      fx_FinalizationRegistryCleanup(the, registry, C_NULL);
      address = &(mxFinalizationRegistries.value.reference->next);
    }
    else
      address = &(closure->next);
  }
}



Coverage Report

Created: 2026-07-16 06:43