source: binary-improvements/7dtd-server-fixes/src/LandClaimList.cs@ 481

using System;
using System.Collections.Generic;
using AllocsFixes.PersistentData;

namespace AllocsFixes {
        public static class LandClaimList {
                public delegate bool OwnerFilter (Player _owner);

                public delegate bool PositionFilter (Vector3i _position);

                public static Dictionary<Player, List<Vector3i>> GetLandClaims (OwnerFilter[] _ownerFilters,
                        PositionFilter[] _positionFilters) {
                        Dictionary<Vector3i, PersistentPlayerData> d = GameManager.Instance.GetPersistentPlayerList ().m_lpBlockMap;
                        Dictionary<Player, List<Vector3i>> result = new Dictionary<Player, List<Vector3i>> ();

                        if (d == null) {
                                return result;
                        }

                        Dictionary<PersistentPlayerData, List<Vector3i>> owners =
                                new Dictionary<PersistentPlayerData, List<Vector3i>> ();
                        foreach (KeyValuePair<Vector3i, PersistentPlayerData> kvp in d) {
                                bool allowed = true;
                                if (_positionFilters != null) {
                                        foreach (PositionFilter pf in _positionFilters) {
                                                if (!pf (kvp.Key)) {
                                                        allowed = false;
                                                        break;
                                                }
                                        }
                                }

                                if (allowed) {
                                        if (!owners.ContainsKey (kvp.Value)) {
                                                owners.Add (kvp.Value, new List<Vector3i> ());
                                        }

                                        owners [kvp.Value].Add (kvp.Key);
                                }
                        }

                        foreach (KeyValuePair<PersistentPlayerData, List<Vector3i>> kvp in owners) {
                                Player p = PersistentContainer.Instance.Players.GetByInternalId (kvp.Key.UserIdentifier);
                                if (p == null) {
                                        PlatformUserIdentifierAbs platformId = kvp.Key.PlatformUserIdentifier;
                                        PlatformUserIdentifierAbs internalId = kvp.Key.UserIdentifier;
                                        PlatformUserIdentifierAbs crossPlatformId = platformId == null || platformId.Equals (internalId) ? null : internalId;
                                        p = new Player (internalId, platformId, crossPlatformId);
                                }

                                bool allowed = true;
                                if (_ownerFilters != null) {
                                        foreach (OwnerFilter of in _ownerFilters) {
                                                if (!of (p)) {
                                                        allowed = false;
                                                        break;
                                                }
                                        }
                                }

                                if (allowed) {
                                        result.Add (p, new List<Vector3i> ());
                                        foreach (Vector3i v in kvp.Value) {
                                                result [p].Add (v);
                                        }
                                }
                        }

                        return result;
                }

                public static OwnerFilter UserIdFilter (PlatformUserIdentifierAbs _userId) {
                        return _p => _p.InternalId.Equals (_userId);
                }

                public static PositionFilter CloseToFilter2dRect (Vector3i _position, int _maxDistance) {
                        return _v => Math.Abs (_v.x - _position.x) <= _maxDistance && Math.Abs (_v.z - _position.z) <= _maxDistance;
                }

                public static OwnerFilter OrOwnerFilter (OwnerFilter _f1, OwnerFilter _f2) {
                        return _p => _f1 (_p) || _f2 (_p);
                }
        }
}