source: binary-improvements/7dtd-server-fixes/src/PlayerDataStuff.cs@ 120

using System;
using System.Collections.Generic;

public class PlayerDataStuff
{
        public class PlayerItems
        {
                public SortedList<string, int> belt = new SortedList<string, int> ();
                public SortedList<string, int> bag = new SortedList<string, int> ();

                public PlayerItems (InventoryField[] _belt, InventoryField[] _bag)
                {
                        foreach (InventoryField item in _belt) {
                                if (item.count > 0) {
                                        string name = getInvFieldName (item);
                                        if (belt.ContainsKey (name)) {
                                                belt [name] += item.count;
                                        } else {
                                                belt.Add (name, item.count);
                                        }
                                }
                        }

                        foreach (InventoryField item in _bag) {
                                if (item.count > 0) {
                                        string name = getInvFieldName (item);
                                        if (bag.ContainsKey (name)) {
                                                bag [name] += item.count;
                                        } else {
                                                bag.Add (name, item.count);
                                        }
                                }
                        }
                }
        };

        private static Dictionary<int, PlayerItems> itemsPerEntityId = new Dictionary<int, PlayerItems> ();

        public static PlayerItems GetPlayerItems (int entityId)
        {
                if (itemsPerEntityId.ContainsKey (entityId))
                        return itemsPerEntityId [entityId];
                else
                        return null;
        }

        public static void GM_SavePlayerData (GameManager manager, int _clientId, PlayerDataFile _playerDataFile)
        {
                try {
                        int entityId = CommonMappingFunctions.GetEntityID (CommonMappingFunctions.GetClientInfoFromClientID (_clientId));
                        if (entityId >= 0) {
                                Log.Out ("Saving playerData for entity id: " + entityId);

                                if (itemsPerEntityId.ContainsKey (entityId))
                                        itemsPerEntityId.Remove (entityId);
                                itemsPerEntityId.Add (entityId, new PlayerItems (_playerDataFile.inventory, _playerDataFile.bag));
                        }
                } catch (Exception e) {
                        Log.Out ("Error in GM_SavePlayerData: " + e);
                }
                /*
                Log.Out ("Inventory of player:");
                for (int i = 0; i < _playerDataFile.inventory.Length; i++) {
                        InventoryField item = _playerDataFile.inventory [i];
                        printItem (item, i);
                }

                Log.Out ("Bag of player:");
                for (int i = 0; i < _playerDataFile.bag.Length; i++) {
                        InventoryField item = _playerDataFile.bag [i];
                        printItem (item, i);
                }*/
        }

        private static string getInvFieldName (InventoryField item)
        {
                ItemBase iBase = ItemBase.list [item.itemValue.type];
                string name = iBase.name;
                if (iBase.IsBlock ()) {
                        ItemBlock iBlock = (ItemBlock)iBase;
                        name = iBlock.GetItemName (item.itemValue);
                }
                return name;
        }

        private static void printItem (InventoryField item, int slot)
        {
                if (item.count > 0) {
                        ItemBase iBase = ItemBase.list [item.itemValue.type];
                        string name = iBase.name;
                        if (iBase.IsBlock ()) {
                                ItemBlock iBlock = (ItemBlock)iBase;
                                name = iBlock.GetItemName (item.itemValue);
                        }
                        Log.Out (string.Format ("Slot {0:00}: {1:00} * {2}", slot, item.count, name));
                }
        }
}