Looping through object manager crash

[zdohdds]

Good evening. Don't know how to write correctly the exit condition from looping.

        // Win 7.1.0.22996 x64
        public const uint Entity = 0x1602B20;
        public const uint Entity_first = 0x18;

        //....
        [StructLayout(LayoutKind.Explicit)]
        public unsafe struct CG_Object
        {
            [FieldOffset(0x10)]
            public ObjectDescriptor* Descriptors;

            [FieldOffset(0x20)]
            public uint EntitiType;

            [FieldOffset(0x70)]
            public IntPtr NextEntity;
        } 

        public static unsafe IntPtr EntityList { get { return new IntPtr(*(long*)(Memory._baseAddress + (int)Offsets.Entity)); } }
        public static unsafe IntPtr EntityFirst { get { return new IntPtr(*(long*)(EntityList + (int)Offsets.Entity_first)); } }

        public static IntPtr GetObjectByGuid(Guid guid)
        {
            IntPtr pointer = EntityFirst;
            while (pointer != IntPtr.Zero)
            {
                WoWObject wowObject = new WoWObject(pointer);
                if (wowObject.Guid == guid) return pointer;
                else pointer = wowObject.NextEntity;
            }
            return IntPtr.Zero;
        } 

This search is working, but, over time, the program crashes, because the last wowObject.NextEntity refers to does not need a value.
When was the last wowObject.NextEntity refers to 0x0, then everything is fine.

What you need to add to lopping always worked, under any circumstances?

[MurderBurger]

If you write out the entity pointers as bits you'll see something like this.

...
1011000101011110010001010010100
1011000101011110100000010101000
1011000101011110101111010111100
1011000101011110111110011010000
1011000101011111001101011100100
1011000101011111011100011111000
1011000101011111101011100001100
1011000101011111111010100100000
1011000101100000001001100110100
1011000101100000011000101001000
1011000101100000100111101011100
1011000101100000110110101110000
1011000101100001000101110000100
1010001111110000011000001110000
1011000101100001110010111000000
1010010010001001100011010010100
1011000101100011011100001001100
1010010010001000110111100011100
1010010010000111100000000101100
1011000101100010011111111111100
1010010010001000001011110100100
1011000101100011111010001110100
1010001111110000010100101001000
1011000101100010010000111101000
1011000101100001010100110011000
1011000101100010111110000100100
0000101011110000001000100100101 ← entity pointer that is causing the crash.

Do you see something special about the last entity pointer?

[zdohdds]

If you write out the entity pointers as bits you'll see something like this.

...
1011000101011110010001010010100
1011000101011110100000010101000
1011000101011110101111010111100
1011000101011110111110011010000
1011000101011111001101011100100
1011000101011111011100011111000
1011000101011111101011100001100
1011000101011111111010100100000
1011000101100000001001100110100
1011000101100000011000101001000
1011000101100000100111101011100
1011000101100000110110101110000
1011000101100001000101110000100
1010001111110000011000001110000
1011000101100001110010111000000
1010010010001001100011010010100
1011000101100011011100001001100
1010010010001000110111100011100
1010010010000111100000000101100
1011000101100010011111111111100
1010010010001000001011110100100
1011000101100011111010001110100
1010001111110000010100101001000
1011000101100010010000111101000
1011000101100001010100110011000
1011000101100010111110000100100
0000101011110000001000100100101 ← entity pointer that is causing the crash.

Do you see something special about the last entity pointer?

Thanks for the quick response. Yes, I know about the first bit, but if I write this condition, it finds nothing, even TargetGUID.

while ((pointer != IntPtr.Zero) && (pointer.ToInt64() & 1 == 0)) 

right? i don't know how to right to do for bits =)

[lolp1]

This is how I always did it externally, should still work fine with updated pointers.

 
    /// <summary>
    ///     A static class to handle creating a list of entites containing the <see cref="WowObjectData" /> structure.
    /// </summary>
    public static class EntityList
    {
        #region Properties
        /// <summary>
        ///     Collects a dictonary of current entitie with the guid as the key.
        /// </summary>
        public static Dictionary<WowGuid, WowObject> EntitiesAsDictionary
        {
            get
            {
                var woWObjects = new Dictionary<WowGuid, WowObject>();
                CollectEntities(GetFirstObject(), woWObjects);
                return woWObjects;
            }
        }

        /// <summary>
        ///     A collection of current entities.
        /// </summary>
        public static IEnumerable<WowObject> Entities => EntitiesAsDictionary.Values.ToList();
        #endregion

        #region Methods
        /// <summary>
        ///     Gets the pointer to the first object in the list.
        /// </summary>
        /// <returns></returns>
        private static IntPtr GetFirstObject()
        {
            var mgr = Wow64.CurrentManager;
            return mgr.VisibleObjects.m_fulllist.baseClass.m_terminator.m_next;
        }

        /// <summary>
        ///     Gets the pointer to the next object in the list.
        /// </summary>
        /// <param name="current">The current objects pointer.</param>
        /// <returns>SetObjectManager pointer to the next object.</returns>
        private static IntPtr GetNextObjectFrom(IntPtr current)
        {
            var mgr = Wow64.CurrentManager;
            return Wow.Memory.Read<IntPtr>(current + mgr.VisibleObjects.m_fulllist.baseClass.m_linkoffset + IntPtr.Size);
        }

        /// <summary>
        ///     Generates the dictonary of entities.
        /// </summary>
        /// <param name="firstObject">The address to the first object of the entity list.</param>
        /// <param name="wowObjectDictionary">The dictonary to fill results with.</param>
        [SuppressMessage("ReSharper", "SwitchStatementMissingSomeCases")]
        private static void CollectEntities(IntPtr firstObject, IDictionary<WowGuid, WowObject> wowObjectDictionary)
        {
            var current = firstObject;
            while (((current.ToInt64() & 1) == 0) && current != IntPtr.Zero)
            {
                var type = (WoWObjectType) Wow.Memory.Read<int>(current + WowOffsets.EntityList.Type);
                switch (type)
                {
                    case WoWObjectType.Item:
                        AddTo(wowObjectDictionary, new WowItem(current));
                        break;

                    case WoWObjectType.Container:
                        AddTo(wowObjectDictionary, new WowContainer(current));
                        break;

                    case WoWObjectType.Unit:
                        AddTo(wowObjectDictionary, new WowUnit(current));
                        break;

                    case WoWObjectType.Player:
                        AddTo(wowObjectDictionary, new WowPlayer(current));
                        break;

                    case WoWObjectType.GameObject:
                        AddTo(wowObjectDictionary, new WowGameObject(current));
                        break;

                    case WoWObjectType.Corpse:
                        AddTo(wowObjectDictionary, new WowCorpse(current));
                        break;

                    default:
                        AddTo(wowObjectDictionary, new WowObject(current));
                        break;
                }
                current = GetNextObjectFrom(current);
            }
        }

        private static void AddTo(IDictionary<WowGuid, WowObject> wowObjects, WowObject wowObject)
        {
            wowObjects.Add(wowObject.Guid, wowObject);
        }
        #endregion
    }

[zdohdds]

Thank you very much.