Reduce implicit null checks

SabreTools.DatFiles/Formats/Logiqx.Reader.cs

@@ -273,7 +273,7 @@ namespace SabreTools.DatFiles.Formats
             ConvertDeviceRefs(game.DeviceRef, machine, filename, indexId, statsOnly, ref containsItems);
             ConvertSamples(game.Sample, machine, filename, indexId, statsOnly, ref containsItems);
             ConvertArchives(game.Archive, machine, filename, indexId, statsOnly, ref containsItems);
-            ConvertDrivers(game.Driver, machine, filename, indexId, statsOnly, ref containsItems);
+            ConvertDriver(game.Driver, machine, filename, indexId, statsOnly, ref containsItems);
             ConvertSoftwareLists(game.SoftwareList, machine, filename, indexId, statsOnly, ref containsItems);
 
             // If we had no items, create a Blank placeholder
@@ -599,42 +599,39 @@ namespace SabreTools.DatFiles.Formats
         /// <summary>
         /// Convert Driver information
         /// </summary>
-        /// <param name="drivers">Array of deserialized models to convert</param>
+        /// <param name="driver">Deserialized model to convert</param>
         /// <param name="machine">Prefilled machine to use</param>
         /// <param name="filename">Name of the file to be parsed</param>
         /// <param name="indexId">Index ID for the DAT</param>
         /// <param name="statsOnly">True to only add item statistics while parsing, false otherwise</param>
         /// <param name="containsItems">True if there were any items in the array, false otherwise</param>
-        private void ConvertDrivers(Models.Logiqx.Driver[]? drivers, Machine machine, string filename, int indexId, bool statsOnly, ref bool containsItems)
+        private void ConvertDriver(Models.Logiqx.Driver? driver, Machine machine, string filename, int indexId, bool statsOnly, ref bool containsItems)
         {
-            // If the drivers array is missing, we can't do anything
+            // If the driver is missing, we can't do anything
-            if (drivers == null || !drivers.Any())
+            if (driver == null)
                 return;
 
             containsItems = true;
-            foreach (var driver in drivers)
+            var item = new Driver
             {
-                var item = new Driver
+                Status = driver.Status?.AsSupportStatus() ?? SupportStatus.NULL,
+                Emulation = driver.Emulation?.AsSupportStatus() ?? SupportStatus.NULL,
+                Cocktail = driver.Cocktail?.AsSupportStatus() ?? SupportStatus.NULL,
+                SaveState = driver.SaveState?.AsSupported() ?? Supported.NULL,
+                RequiresArtwork = driver.RequiresArtwork?.AsYesNo(),
+                Unofficial = driver.Unofficial?.AsYesNo(),
+                NoSoundHardware = driver.NoSoundHardware?.AsYesNo(),
+                Incomplete = driver.Incomplete?.AsYesNo(),
+
+                Source = new Source
                 {
-                    Status = driver.Status?.AsSupportStatus() ?? SupportStatus.NULL,
+                    Index = indexId,
-                    Emulation = driver.Emulation?.AsSupportStatus() ?? SupportStatus.NULL,
+                    Name = filename,
-                    Cocktail = driver.Cocktail?.AsSupportStatus() ?? SupportStatus.NULL,
+                },
-                    SaveState = driver.SaveState?.AsSupported() ?? Supported.NULL,
+            };
-                    RequiresArtwork = driver.RequiresArtwork?.AsYesNo(),
-                    Unofficial = driver.Unofficial?.AsYesNo(),
-                    NoSoundHardware = driver.NoSoundHardware?.AsYesNo(),
-                    Incomplete = driver.Incomplete?.AsYesNo(),
 
-                    Source = new Source
+            item.CopyMachineInformation(machine);
-                    {
+            ParseAddHelper(item, statsOnly);
-                        Index = indexId,
-                        Name = filename,
-                    },
-                };
-
-                item.CopyMachineInformation(machine);
-                ParseAddHelper(item, statsOnly);
-            }
         }
 
         /// <summary>

SabreTools.DatFiles/Formats/Logiqx.Writer.cs

@@ -314,7 +314,6 @@ namespace SabreTools.DatFiles.Formats
                 var samples = new List<Models.Logiqx.Sample>();
                 var archives = new List<Models.Logiqx.Archive>();
                 var devicerefs = new List<Models.Logiqx.DeviceRef>();
-                var drivers = new List<Models.Logiqx.Driver>();
                 var softwarelists = new List<Models.Logiqx.SoftwareList>();
 
                 // Loop through and convert the items to respective lists
@@ -357,7 +356,7 @@ namespace SabreTools.DatFiles.Formats
                             devicerefs.Add(CreateDeviceRef(deviceref));
                             break;
                         case Driver driver:
-                            drivers.Add(CreateDriver(driver));
+                            game.Driver = CreateDriver(driver);
                             break;
                         case DatItems.Formats.SoftwareList softwarelist:
                             softwarelists.Add(CreateSoftwareList(softwarelist));
@@ -374,7 +373,6 @@ namespace SabreTools.DatFiles.Formats
                 game.Sample = samples.ToArray();
                 game.Archive = archives.ToArray();
                 game.DeviceRef = devicerefs.ToArray();
-                game.Driver = drivers.ToArray();
                 game.SoftwareList = softwarelists.ToArray();
 
                 // Add the game to the list

SabreTools.Models/ClrMamePro/GameBase.cs

@@ -60,7 +60,7 @@ namespace SabreTools.Models.ClrMamePro
         public Chip[]? Chip { get; set; }
 
         /// <remarks>video, Appears after Chip</remarks>
-        public Video? Video { get; set; }
+        public Video[]? Video { get; set; }
 
         /// <remarks>sound, Appears after Video</remarks>
         public Sound? Sound { get; set; }

SabreTools.Models/Internal/Machine.cs

@@ -61,6 +61,9 @@ namespace SabreTools.Models.Internal
         /// <remarks>DipSwitch[]</remarks>
         public const string DipSwitchKey = "dipswitch";
 
+        /// <remarks>string</remarks>
+        public const string DirNameKey = "dirName";
+
         /// <remarks>Disk[]</remarks>
         public const string DiskKey = "disk";
 
@@ -73,7 +76,7 @@ namespace SabreTools.Models.Internal
         /// <remarks>string</remarks>
         public const string DisplayTypeKey = "displaytype";
 
-        /// <remarks>Driver, Driver[]</remarks>
+        /// <remarks>Driver</remarks>
         public const string DriverKey = "driver";
 
         /// <remarks>Dump[]</remarks>
@@ -230,7 +233,7 @@ namespace SabreTools.Models.Internal
         /// <remarks>Trurip</remarks>
         public const string TruripKey = "trurip";
 
-        /// <remarks>Video, Video[]</remarks>
+        /// <remarks>Video[]</remarks>
         public const string VideoKey = "video";
 
         /// <remarks>string</remarks>

SabreTools.Models/Logiqx/GameBase.cs

@@ -102,10 +102,9 @@ namespace SabreTools.Models.Logiqx
         [XmlElement("archive")]
         public Archive[]? Archive { get; set; }
 
-        /// TODO: Validate multiple can exist
         /// <remarks>MAME extension</remarks>
         [XmlElement("driver")]
-        public Driver[]? Driver { get; set; }
+        public Driver? Driver { get; set; }
 
         /// <remarks>MAME extension</remarks>
         [XmlElement("softwarelist")]

SabreTools.Serialization/ArchiveDotOrg.Deserializer.cs

@@ -1,3 +1,4 @@
+using System;
 using System.Linq;
 using SabreTools.Models.ArchiveDotOrg;
 
@@ -22,7 +23,12 @@ namespace SabreTools.Serialization
 
             var machines = item.Read<Models.Internal.Machine[]>(Models.Internal.MetadataFile.MachineKey);
             if (machines != null && machines.Any())
-                files.File = machines.SelectMany(ConvertFromInternalModel).ToArray();
+            {
+                files.File = machines
+                .Where(m => m != null)
+                .SelectMany(ConvertFromInternalModel)
+                .ToArray();
+            }
 
             return files;
         }
@@ -30,23 +36,22 @@ namespace SabreTools.Serialization
         /// <summary>
         /// Convert from <cref="Models.Internal.Machine"/> to an array of <cref="Models.ArchiveDotOrg.File"/>
         /// </summary>
-        private static File[]? ConvertFromInternalModel(Models.Internal.Machine? item)
+        private static File[] ConvertFromInternalModel(Models.Internal.Machine item)
         {
-            if (item == null)
-                return null;
-
             var roms = item.Read<Models.Internal.Rom[]>(Models.Internal.Machine.RomKey);
-            return roms?.Select(ConvertFromInternalModel)?.ToArray();
+            if (roms == null)
+                return Array.Empty<File>();
+
+            return roms
+                .Where(r => r != null)
+                .Select(ConvertFromInternalModel).ToArray();
         }
 
         /// <summary>
         /// Convert from <cref="Models.Internal.Rom"/> to <cref="Models.ArchiveDotOrg.File"/>
         /// </summary>
-        private static File? ConvertFromInternalModel(Models.Internal.Rom? item)
+        private static File ConvertFromInternalModel(Models.Internal.Rom item)
         {
-            if (item == null)
-                return null;
-
             var file = new File
             {
                 Name = item.ReadString(Models.Internal.Rom.NameKey),

SabreTools.Serialization/ArchiveDotOrg.Serializer.cs

@@ -13,15 +13,23 @@ namespace SabreTools.Serialization
         /// <summary>
         /// Convert from <cref="Models.ArchiveDotOrg.Files"/> to <cref="Models.Internal.MetadataFile"/>
         /// </summary>
-        public static Models.Internal.MetadataFile ConvertToInternalModel(Files item)
+        public static Models.Internal.MetadataFile? ConvertToInternalModel(Files? item)
         {
+            if (item == null)
+                return null;
+            
             var metadataFile = new Models.Internal.MetadataFile
             {
                 [Models.Internal.MetadataFile.HeaderKey] = ConvertHeaderToInternalModel(item),
             };
 
             if (item?.File != null && item.File.Any())
-                metadataFile[Models.Internal.MetadataFile.MachineKey] = item.File.Select(ConvertMachineToInternalModel).ToArray();
+            {
+                metadataFile[Models.Internal.MetadataFile.MachineKey] = item.File
+                    .Where(f => f != null)
+                    .Select(ConvertMachineToInternalModel)
+                    .ToArray();
+            }
 
             return metadataFile;
         }

SabreTools.Serialization/AttractMode.Deserializer.cs

@@ -1,3 +1,4 @@
+using System;
 using System.Collections.Generic;
 using System.IO;
 using System.Linq;
@@ -136,7 +137,12 @@ namespace SabreTools.Serialization
 
             var machines = item.Read<Models.Internal.Machine[]>(Models.Internal.MetadataFile.MachineKey);
             if (machines != null && machines.Any())
-                metadataFile.Row = machines.SelectMany(ConvertMachineFromInternalModel).ToArray();
+            {
+                metadataFile.Row = machines
+                    .Where(m => m != null)
+                    .SelectMany(ConvertMachineFromInternalModel)
+                    .ToArray();
+            }
 
             return metadataFile;
         }
@@ -144,11 +150,8 @@ namespace SabreTools.Serialization
         /// <summary>
         /// Convert from <cref="Models.Internal.Header"/> to <cref="Models.AttractMode.MetadataFile"/>
         /// </summary>
-        private static MetadataFile? ConvertHeaderFromInternalModel(Models.Internal.Header? item)
+        private static MetadataFile ConvertHeaderFromInternalModel(Models.Internal.Header item)
         {
-            if (item == null)
-                return null;
-
             var metadataFile = new MetadataFile
             {
                 Header = item.ReadStringArray(Models.Internal.Header.HeaderKey),
@@ -159,55 +162,46 @@ namespace SabreTools.Serialization
         /// <summary>
         /// Convert from <cref="Models.Internal.Machine"/> to an array of <cref="Models.AttractMode.Row"/>
         /// </summary>
-        private static Row?[]? ConvertMachineFromInternalModel(Models.Internal.Machine? item)
+        private static Row[] ConvertMachineFromInternalModel(Models.Internal.Machine item)
         {
-            if (item == null)
-                return null;
-
             var roms = item.Read<Models.Internal.Rom[]>(Models.Internal.Machine.RomKey);
-            return roms?.Select(rom =>
+            if (roms == null || !roms.Any())
-            {
+                return Array.Empty<Row>();
-                if (rom == null)
-                    return null;
 
-                var rowItem = ConvertFromInternalModel(rom);
+            return roms
-
+                .Where(r => r != null)
-                rowItem.Name = item.ReadString(Models.Internal.Machine.NameKey);
+                .Select(rom => ConvertFromInternalModel(rom, item))
-                rowItem.Emulator = item.ReadString(Models.Internal.Machine.EmulatorKey);
+                .ToArray();
-                rowItem.CloneOf = item.ReadString(Models.Internal.Machine.CloneOfKey);
-                rowItem.Year = item.ReadString(Models.Internal.Machine.YearKey);
-                rowItem.Manufacturer = item.ReadString(Models.Internal.Machine.ManufacturerKey);
-                rowItem.Category = item.ReadString(Models.Internal.Machine.CategoryKey);
-                rowItem.Players = item.ReadString(Models.Internal.Machine.PlayersKey);
-                rowItem.Rotation = item.ReadString(Models.Internal.Machine.RotationKey);
-                rowItem.Control = item.ReadString(Models.Internal.Machine.ControlKey);
-                rowItem.Status = item.ReadString(Models.Internal.Machine.StatusKey);
-                rowItem.DisplayCount = item.ReadString(Models.Internal.Machine.DisplayCountKey);
-                rowItem.DisplayType = item.ReadString(Models.Internal.Machine.DisplayTypeKey);
-                rowItem.Extra = item.ReadString(Models.Internal.Machine.ExtraKey);
-                rowItem.Buttons = item.ReadString(Models.Internal.Machine.ButtonsKey);
-                rowItem.Favorite = item.ReadString(Models.Internal.Machine.FavoriteKey);
-                rowItem.Tags = item.ReadString(Models.Internal.Machine.TagsKey);
-                rowItem.PlayedCount = item.ReadString(Models.Internal.Machine.PlayedCountKey);
-                rowItem.PlayedTime = item.ReadString(Models.Internal.Machine.PlayedTimeKey);
-
-                return rowItem;
-            })?.ToArray();
         }
 
         /// <summary>
         /// Convert from <cref="Models.Internal.Rom"/> to <cref="Models.AttractMode.Row"/>
         /// </summary>
-        private static Row? ConvertFromInternalModel(Models.Internal.Rom? item)
+        private static Row ConvertFromInternalModel(Models.Internal.Rom item, Models.Internal.Machine parent)
         {
-            if (item == null)
-                return null;
-
             var row = new Row
             {
+                Name = parent.ReadString(Models.Internal.Machine.NameKey),
                 Title = item.ReadString(Models.Internal.Rom.NameKey),
+                Emulator = parent.ReadString(Models.Internal.Machine.EmulatorKey),
+                CloneOf = parent.ReadString(Models.Internal.Machine.CloneOfKey),
+                Year = parent.ReadString(Models.Internal.Machine.YearKey),
+                Manufacturer = parent.ReadString(Models.Internal.Machine.ManufacturerKey),
+                Category = parent.ReadString(Models.Internal.Machine.CategoryKey),
+                Players = parent.ReadString(Models.Internal.Machine.PlayersKey),
+                Rotation = parent.ReadString(Models.Internal.Machine.RotationKey),
+                Control = parent.ReadString(Models.Internal.Machine.ControlKey),
+                Status = parent.ReadString(Models.Internal.Machine.StatusKey),
+                DisplayCount = parent.ReadString(Models.Internal.Machine.DisplayCountKey),
+                DisplayType = parent.ReadString(Models.Internal.Machine.DisplayTypeKey),
                 AltRomname = item.ReadString(Models.Internal.Rom.AltRomnameKey),
                 AltTitle = item.ReadString(Models.Internal.Rom.AltTitleKey),
+                Extra = parent.ReadString(Models.Internal.Machine.ExtraKey),
+                Buttons = parent.ReadString(Models.Internal.Machine.ButtonsKey),
+                Favorite = parent.ReadString(Models.Internal.Machine.FavoriteKey),
+                Tags = parent.ReadString(Models.Internal.Machine.TagsKey),
+                PlayedCount = parent.ReadString(Models.Internal.Machine.PlayedCountKey),
+                PlayedTime = parent.ReadString(Models.Internal.Machine.PlayedTimeKey),
                 FileIsAvailable = item.ReadString(Models.Internal.Rom.FileIsAvailableKey),
             };
             return row;

SabreTools.Serialization/AttractMode.Serializer.cs

@@ -105,15 +105,23 @@ namespace SabreTools.Serialization
         /// <summary>
         /// Convert from <cref="Models.AttractMode.MetadataFile"/> to <cref="Models.Internal.MetadataFile"/>
         /// </summary>
-        public static Models.Internal.MetadataFile ConvertToInternalModel(MetadataFile item)
+        public static Models.Internal.MetadataFile? ConvertToInternalModel(MetadataFile? item)
         {
+            if (item == null)
+                return null;
+            
             var metadataFile = new Models.Internal.MetadataFile
             {
                 [Models.Internal.MetadataFile.HeaderKey] = ConvertHeaderToInternalModel(item),
             };
 
             if (item?.Row != null && item.Row.Any())
-                metadataFile[Models.Internal.MetadataFile.MachineKey] = item.Row.Select(ConvertMachineToInternalModel).ToArray();
+            {
+                metadataFile[Models.Internal.MetadataFile.MachineKey] = item.Row
+                    .Where(r => r != null)
+                    .Select(ConvertMachineToInternalModel)
+                    .ToArray();
+            }
 
             return metadataFile;
         }

SabreTools.Serialization/ClrMamePro.Deserializer.cs

@@ -53,6 +53,7 @@ namespace SabreTools.Serialization
             var samples = new List<Sample>();
             var archives = new List<Archive>();
             var chips = new List<Chip>();
+            var videos = new List<Video>();
             var dipSwitches = new List<DipSwitch>();
 
             var additional = new List<string>();
@@ -89,6 +90,7 @@ namespace SabreTools.Serialization
                                 game.Sample = samples.ToArray();
                                 game.Archive = archives.ToArray();
                                 game.Chip = chips.ToArray();
+                                game.Video = videos.ToArray();
                                 game.DipSwitch = dipSwitches.ToArray();
                                 game.ADDITIONAL_ELEMENTS = gameAdditional.ToArray();
 
@@ -103,6 +105,7 @@ namespace SabreTools.Serialization
                                 samples.Clear();
                                 archives.Clear();
                                 chips.Clear();
+                                videos.Clear();
                                 dipSwitches.Clear();
                                 gameAdditional.Clear();
                                 break;
@@ -293,7 +296,7 @@ namespace SabreTools.Serialization
                             chips.Add(CreateChip(reader));
                             break;
                         case "video":
-                            game.Video = CreateVideo(reader);
+                            videos.Add(CreateVideo(reader));
                             break;
                         case "sound":
                             game.Sound = CreateSound(reader);
@@ -848,7 +851,12 @@ namespace SabreTools.Serialization
 
             var machines = item.Read<Models.Internal.Machine[]>(Models.Internal.MetadataFile.MachineKey);
             if (machines != null && machines.Any())
-                metadataFile.Game = machines.Select(machine => ConvertMachineFromInternalModel(machine, game)).ToArray();
+            {
+                metadataFile.Game = machines
+                    .Where(m => m != null)
+                    .Select(machine => ConvertMachineFromInternalModel(machine, game))
+                    .ToArray();
+            }
 
             return metadataFile;
         }
@@ -856,11 +864,8 @@ namespace SabreTools.Serialization
         /// <summary>
         /// Convert from <cref="Models.Internal.Header"/> to <cref="Models.ClrMamePro.ClrMamePro"/>
         /// </summary>
-        private static Models.ClrMamePro.ClrMamePro? ConvertHeaderFromInternalModel(Models.Internal.Header? item)
+        private static Models.ClrMamePro.ClrMamePro ConvertHeaderFromInternalModel(Models.Internal.Header item)
         {
-            if (item == null)
-                return null;
-
             var clrMamePro = new Models.ClrMamePro.ClrMamePro
             {
                 Name = item.ReadString(Models.Internal.Header.NameKey),
@@ -885,11 +890,8 @@ namespace SabreTools.Serialization
         /// <summary>
         /// Convert from <cref="Models.Internal.Archive"/> to <cref="Models.ClrMamePro.Machine"/>
         /// </summary>
-        private static GameBase? ConvertMachineFromInternalModel(Models.Internal.Machine? item, bool game = false)
+        private static GameBase ConvertMachineFromInternalModel(Models.Internal.Machine item, bool game = false)
         {
-            if (item == null)
-                return null;
-
             GameBase gameBase = game ? new Models.ClrMamePro.Game() : new Models.ClrMamePro.Machine();
 
             gameBase.Name = item.ReadString(Models.Internal.Machine.NameKey);
@@ -902,43 +904,106 @@ namespace SabreTools.Serialization
             gameBase.SampleOf = item.ReadString(Models.Internal.Machine.SampleOfKey);
 
             var releases = item.Read<Models.Internal.Release[]>(Models.Internal.Machine.ReleaseKey);
-            gameBase.Release = releases?.Select(ConvertFromInternalModel)?.ToArray();
+            if (releases != null && releases.Any())
+            {
+                gameBase.Release = releases
+                    .Where(r => r != null)
+                    .Select(ConvertFromInternalModel)
+                    .ToArray();
+            }
 
             var biosSets = item.Read<Models.Internal.BiosSet[]>(Models.Internal.Machine.BiosSetKey);
-            gameBase.BiosSet = biosSets?.Select(ConvertFromInternalModel)?.ToArray();
+            if (biosSets != null && biosSets.Any())
+            {
+                gameBase.BiosSet = biosSets
+                    .Where(r => r != null)
+                    .Select(ConvertFromInternalModel)
+                    .ToArray();
+            }
 
             var roms = item.Read<Models.Internal.Rom[]>(Models.Internal.Machine.RomKey);
-            gameBase.Rom = roms?.Select(ConvertFromInternalModel)?.ToArray();
+            if (roms != null && roms.Any())
+            {
+                gameBase.Rom = roms
+                    .Where(r => r != null)
+                    .Select(ConvertFromInternalModel)
+                    .ToArray();
+            }
 
             var disks = item.Read<Models.Internal.Disk[]>(Models.Internal.Machine.DiskKey);
-            gameBase.Disk = disks?.Select(ConvertFromInternalModel)?.ToArray();
+            if (disks != null && disks.Any())
+            {
+                gameBase.Disk = disks
+                    .Where(d => d != null)
+                    .Select(ConvertFromInternalModel)
+                    .ToArray();
+            }
 
             var medias = item.Read<Models.Internal.Media[]>(Models.Internal.Machine.MediaKey);
-            gameBase.Media = medias?.Select(ConvertFromInternalModel)?.ToArray();
+            if (medias != null && medias.Any())
+            {
+                gameBase.Media = medias
+                    .Where(m => m != null)
+                    .Select(ConvertFromInternalModel)
+                    .ToArray();
+            }
 
             var samples = item.Read<Models.Internal.Sample[]>(Models.Internal.Machine.SampleKey);
-            gameBase.Sample = samples?.Select(ConvertFromInternalModel)?.ToArray();
+            if (samples != null && samples.Any())
+            {
+                gameBase.Sample = samples
+                    .Where(m => m != null)
+                    .Select(ConvertFromInternalModel)
+                    .ToArray();
+            }
 
             var archives = item.Read<Models.Internal.Archive[]>(Models.Internal.Machine.ArchiveKey);
-            gameBase.Archive = archives?.Select(ConvertFromInternalModel)?.ToArray();
+            if (archives != null && archives.Any())
+            {
+                gameBase.Archive = archives
+                    .Where(m => m != null)
+                    .Select(ConvertFromInternalModel)
+                    .ToArray();
+            }
 
             var chips = item.Read<Models.Internal.Chip[]>(Models.Internal.Machine.ChipKey);
-            gameBase.Chip = chips?.Select(ConvertFromInternalModel)?.ToArray();
+            if (chips != null && chips.Any())
+            {
+                gameBase.Chip = chips
+                    .Where(m => m != null)
+                    .Select(ConvertFromInternalModel)
+                    .ToArray();
+            }
 
-            var video = item.Read<Models.Internal.Video>(Models.Internal.Machine.VideoKey);
+            var videos = item.Read<Models.Internal.Video[]>(Models.Internal.Machine.VideoKey);
-            gameBase.Video = ConvertFromInternalModel(video);
+            if (videos != null && videos.Any())
+            {
+                gameBase.Video = videos
+                    .Where(m => m != null)
+                    .Select(ConvertFromInternalModel)
+                    .ToArray();
+            }
 
             var sound = item.Read<Models.Internal.Sound>(Models.Internal.Machine.SoundKey);
-            gameBase.Sound = ConvertFromInternalModel(sound);
+            if (sound != null)
+                gameBase.Sound = ConvertFromInternalModel(sound);
 
             var input = item.Read<Models.Internal.Input>(Models.Internal.Machine.InputKey);
-            gameBase.Input = ConvertFromInternalModel(input);
+            if (input != null)
+                gameBase.Input = ConvertFromInternalModel(input);
 
             var dipSwitches = item.Read<Models.Internal.DipSwitch[]>(Models.Internal.Machine.DipSwitchKey);
-            gameBase.DipSwitch = dipSwitches?.Select(ConvertFromInternalModel)?.ToArray();
+            if (dipSwitches != null && dipSwitches.Any())
+            {
+                gameBase.DipSwitch = dipSwitches
+                    .Where(m => m != null)
+                    .Select(ConvertFromInternalModel)
+                    .ToArray();
+            }
 
             var driver = item.Read<Models.Internal.Driver>(Models.Internal.Machine.DriverKey);
-            gameBase.Driver = ConvertFromInternalModel(driver);
+            if (driver != null)
+                gameBase.Driver = ConvertFromInternalModel(driver);
 
             return gameBase;
         }
@@ -946,11 +1011,8 @@ namespace SabreTools.Serialization
         /// <summary>
         /// Convert from <cref="Models.Internal.Archive"/> to <cref="Models.ClrMamePro.Archive"/>
         /// </summary>
-        private static Archive? ConvertFromInternalModel(Models.Internal.Archive? item)
+        private static Archive ConvertFromInternalModel(Models.Internal.Archive item)
         {
-            if (item == null)
-                return null;
-
             var archive = new Archive
             {
                 Name = item.ReadString(Models.Internal.Archive.NameKey),
@@ -961,11 +1023,8 @@ namespace SabreTools.Serialization
         /// <summary>
         /// Convert from <cref="Models.Internal.BiosSet"/> to <cref="Models.ClrMamePro.BiosSet"/>
         /// </summary>
-        private static BiosSet? ConvertFromInternalModel(Models.Internal.BiosSet? item)
+        private static BiosSet ConvertFromInternalModel(Models.Internal.BiosSet item)
         {
-            if (item == null)
-                return null;
-
             var biosset = new BiosSet
             {
                 Name = item.ReadString(Models.Internal.BiosSet.NameKey),
@@ -978,11 +1037,8 @@ namespace SabreTools.Serialization
         /// <summary>
         /// Convert from <cref="Models.Internal.Chip"/> to <cref="Models.ClrMamePro.Chip"/>
         /// </summary>
-        private static Chip? ConvertFromInternalModel(Models.Internal.Chip? item)
+        private static Chip ConvertFromInternalModel(Models.Internal.Chip item)
         {
-            if (item == null)
-                return null;
-
             var chip = new Chip
             {
                 Type = item.ReadString(Models.Internal.Chip.ChipTypeKey),
@@ -996,11 +1052,8 @@ namespace SabreTools.Serialization
         /// <summary>
         /// Convert from <cref="Models.Internal.DipSwitch"/> to <cref="Models.ClrMamePro.DipSwitch"/>
         /// </summary>
-        private static DipSwitch? ConvertFromInternalModel(Models.Internal.DipSwitch? item)
+        private static DipSwitch ConvertFromInternalModel(Models.Internal.DipSwitch item)
         {
-            if (item == null)
-                return null;
-
             var dipswitch = new DipSwitch
             {
                 Name = item.ReadString(Models.Internal.DipSwitch.NameKey),
@@ -1013,11 +1066,8 @@ namespace SabreTools.Serialization
         /// <summary>
         /// Convert from <cref="Models.Internal.Disk"/> to <cref="Models.ClrMamePro.Disk"/>
         /// </summary>
-        private static Disk? ConvertFromInternalModel(Models.Internal.Disk? item)
+        private static Disk ConvertFromInternalModel(Models.Internal.Disk item)
         {
-            if (item == null)
-                return null;
-
             var disk = new Disk
             {
                 Name = item.ReadString(Models.Internal.Disk.NameKey),
@@ -1033,11 +1083,8 @@ namespace SabreTools.Serialization
         /// <summary>
         /// Convert from <cref="Models.Internal.Driver"/> to <cref="Models.ClrMamePro.Driver"/>
         /// </summary>
-        private static Driver? ConvertFromInternalModel(Models.Internal.Driver? item)
+        private static Driver ConvertFromInternalModel(Models.Internal.Driver item)
         {
-            if (item == null)
-                return null;
-
             var driver = new Driver
             {
                 Status = item.ReadString(Models.Internal.Driver.StatusKey),
@@ -1052,11 +1099,8 @@ namespace SabreTools.Serialization
         /// <summary>
         /// Convert from <cref="Models.Internal.Input"/> to <cref="Models.ClrMamePro.Input"/>
         /// </summary>
-        private static Input? ConvertFromInternalModel(Models.Internal.Input? item)
+        private static Input ConvertFromInternalModel(Models.Internal.Input item)
         {
-            if (item == null)
-                return null;
-
             var input = new Input
             {
                 Players = item.ReadString(Models.Internal.Input.PlayersKey),
@@ -1072,11 +1116,8 @@ namespace SabreTools.Serialization
         /// <summary>
         /// Convert from <cref="Models.Internal.Media"/> to <cref="Models.ClrMamePro.Media"/>
         /// </summary>
-        private static Media? ConvertFromInternalModel(Models.Internal.Media? item)
+        private static Media ConvertFromInternalModel(Models.Internal.Media item)
         {
-            if (item == null)
-                return null;
-
             var media = new Media
             {
                 Name = item.ReadString(Models.Internal.Media.NameKey),
@@ -1091,11 +1132,8 @@ namespace SabreTools.Serialization
         /// <summary>
         /// Convert from <cref="Models.Internal.Release"/> to <cref="Models.ClrMamePro.Release"/>
         /// </summary>
-        private static Release? ConvertFromInternalModel(Models.Internal.Release? item)
+        private static Release ConvertFromInternalModel(Models.Internal.Release item)
         {
-            if (item == null)
-                return null;
-
             var release = new Release
             {
                 Name = item.ReadString(Models.Internal.Release.NameKey),
@@ -1110,11 +1148,8 @@ namespace SabreTools.Serialization
         /// <summary>
         /// Convert from <cref="Models.Internal.Rom"/> to <cref="Models.ClrMamePro.Rom"/>
         /// </summary>
-        private static Rom? ConvertFromInternalModel(Models.Internal.Rom? item)
+        private static Rom ConvertFromInternalModel(Models.Internal.Rom item)
         {
-            if (item == null)
-                return null;
-
             var rom = new Rom
             {
                 Name = item.ReadString(Models.Internal.Rom.NameKey),
@@ -1145,11 +1180,8 @@ namespace SabreTools.Serialization
         /// <summary>
         /// Convert from <cref="Models.Internal.Sample"/> to <cref="Models.ClrMamePro.Sample"/>
         /// </summary>
-        private static Sample? ConvertFromInternalModel(Models.Internal.Sample? item)
+        private static Sample ConvertFromInternalModel(Models.Internal.Sample item)
         {
-            if (item == null)
-                return null;
-
             var sample = new Sample
             {
                 Name = item.ReadString(Models.Internal.Sample.NameKey),
@@ -1160,11 +1192,8 @@ namespace SabreTools.Serialization
         /// <summary>
         /// Convert from <cref="Models.Internal.Sound"/> to <cref="Models.ClrMamePro.Sound"/>
         /// </summary>
-        private static Sound? ConvertFromInternalModel(Models.Internal.Sound? item)
+        private static Sound ConvertFromInternalModel(Models.Internal.Sound item)
         {
-            if (item == null)
-                return null;
-
             var sound = new Sound
             {
                 Channels = item.ReadString(Models.Internal.Sound.ChannelsKey),
@@ -1175,11 +1204,8 @@ namespace SabreTools.Serialization
         /// <summary>
         /// Convert from <cref="Models.Internal.Video"/> to <cref="Models.ClrMamePro.Video"/>
         /// </summary>
-        private static Video? ConvertFromInternalModel(Models.Internal.Video? item)
+        private static Video ConvertFromInternalModel(Models.Internal.Video item)
         {
-            if (item == null)
-                return null;
-
             var video = new Video
             {
                 Screen = item.ReadString(Models.Internal.Video.ScreenKey),

SabreTools.Serialization/ClrMamePro.Serializer.cs

@@ -4,6 +4,7 @@ using System.Linq;
 using System.Text;
 using SabreTools.IO.Writers;
 using SabreTools.Models.ClrMamePro;
+
 namespace SabreTools.Serialization
 {
     /// <summary>
@@ -154,7 +155,7 @@ namespace SabreTools.Serialization
             WriteSamples(game.Sample, writer);
             WriteArchives(game.Archive, writer);
             WriteChips(game.Chip, writer);
-            WriteVideo(game.Video, writer);
+            WriteVideos(game.Video, writer);
             WriteSound(game.Sound, writer);
             WriteInput(game.Input, writer);
             WriteDipSwitches(game.DipSwitch, writer);
@@ -356,23 +357,26 @@ namespace SabreTools.Serialization
         /// <summary>
         /// Write video information to the current writer
         /// </summary>
-        /// <param name="video">Video object to write</param>
+        /// <param name="videos">Array of Video objects to write</param>
         /// <param name="writer">ClrMameProWriter representing the output</param>
-        private static void WriteVideo(Video? video, ClrMameProWriter writer)
+        private static void WriteVideos(Video[]? videos, ClrMameProWriter writer)
         {
             // If the item is missing, we can't do anything
-            if (video == null)
+            if (videos == null)
                 return;
 
-            writer.WriteStartElement("video");
+            foreach (var video in videos)
-            writer.WriteRequiredAttributeString("screen", video.Screen, throwOnError: true);
+            {
-            writer.WriteRequiredAttributeString("orientation", video.Orientation, throwOnError: true);
+                writer.WriteStartElement("video");
-            writer.WriteOptionalAttributeString("x", video.X);
+                writer.WriteRequiredAttributeString("screen", video.Screen, throwOnError: true);
-            writer.WriteOptionalAttributeString("y", video.Y);
+                writer.WriteRequiredAttributeString("orientation", video.Orientation, throwOnError: true);
-            writer.WriteOptionalAttributeString("aspectx", video.AspectX);
+                writer.WriteOptionalAttributeString("x", video.X);
-            writer.WriteOptionalAttributeString("aspecty", video.AspectY);
+                writer.WriteOptionalAttributeString("y", video.Y);
-            writer.WriteOptionalAttributeString("freq", video.Freq);
+                writer.WriteOptionalAttributeString("aspectx", video.AspectX);
-            writer.WriteEndElement(); // video
+                writer.WriteOptionalAttributeString("aspecty", video.AspectY);
+                writer.WriteOptionalAttributeString("freq", video.Freq);
+                writer.WriteEndElement(); // video
+            }
         }
 
         /// <summary>
@@ -461,15 +465,23 @@ namespace SabreTools.Serialization
         /// <summary>
         /// Convert from <cref="Models.ClrMamePro.MetadataFile"/> to <cref="Models.Internal.MetadataFile"/>
         /// </summary>
-        public static Models.Internal.MetadataFile ConvertToInternalModel(MetadataFile item)
+        public static Models.Internal.MetadataFile? ConvertToInternalModel(MetadataFile? item)
         {
+            if (item == null)
+                return null;
+
             var metadataFile = new Models.Internal.MetadataFile();
 
             if (item?.ClrMamePro != null)
                 metadataFile[Models.Internal.MetadataFile.HeaderKey] = ConvertHeaderToInternalModel(item.ClrMamePro);
 
             if (item?.Game != null && item.Game.Any())
-                metadataFile[Models.Internal.MetadataFile.MachineKey] = item.Game.Select(ConvertMachineToInternalModel).ToArray();
+            {
+                metadataFile[Models.Internal.MetadataFile.MachineKey] = item.Game
+                    .Where(g => g != null)
+                    .Select(ConvertMachineToInternalModel)
+                    .ToArray();
+            }
 
             return metadataFile;
         }
@@ -518,31 +530,76 @@ namespace SabreTools.Serialization
             };
 
             if (item.Release != null && item.Release.Any())
-                machine[Models.Internal.Machine.ReleaseKey] = item.Release?.Select(ConvertToInternalModel)?.ToArray();
+            {
+                machine[Models.Internal.Machine.ReleaseKey] = item.Release
+                    .Where(r => r != null)
+                    .Select(ConvertToInternalModel)
+                    .ToArray();
+            }
 
             if (item.BiosSet != null && item.BiosSet.Any())
-                machine[Models.Internal.Machine.BiosSetKey] = item.BiosSet?.Select(ConvertToInternalModel)?.ToArray();
+            {
+                machine[Models.Internal.Machine.BiosSetKey] = item.BiosSet
+                    .Where(b => b != null)
+                    .Select(ConvertToInternalModel)
+                    .ToArray();
+            }
 
             if (item.Rom != null && item.Rom.Any())
-                machine[Models.Internal.Machine.RomKey] = item.Rom?.Select(ConvertToInternalModel)?.ToArray();
+            {
+                machine[Models.Internal.Machine.RomKey] = item.Rom
+                    .Where(r => r != null)
+                .Select(ConvertToInternalModel)
+                .ToArray();
+            }
 
             if (item.Disk != null && item.Disk.Any())
-                machine[Models.Internal.Machine.DiskKey] = item.Disk?.Select(ConvertToInternalModel)?.ToArray();
+            {
+                machine[Models.Internal.Machine.DiskKey] = item.Disk
+                    .Where(d => d != null)
+                    .Select(ConvertToInternalModel)
+                    .ToArray();
+            }
 
             if (item.Media != null && item.Media.Any())
-                machine[Models.Internal.Machine.MediaKey] = item.Media?.Select(ConvertToInternalModel)?.ToArray();
+            {
+                machine[Models.Internal.Machine.MediaKey] = item.Media
+                    .Where(m => m != null)
+                    .Select(ConvertToInternalModel)
+                    .ToArray();
+            }
 
             if (item.Sample != null && item.Sample.Any())
-                machine[Models.Internal.Machine.SampleKey] = item.Sample?.Select(ConvertToInternalModel)?.ToArray();
+            {
+                machine[Models.Internal.Machine.SampleKey] = item.Sample
+                    .Where(s => s != null)
+                    .Select(ConvertToInternalModel)
+                    .ToArray();
+            }
 
             if (item.Archive != null && item.Archive.Any())
-                machine[Models.Internal.Machine.ArchiveKey] = item.Archive?.Select(ConvertToInternalModel)?.ToArray();
+            {
+                machine[Models.Internal.Machine.ArchiveKey] = item.Archive
+                    .Where(a => a != null)
+                    .Select(ConvertToInternalModel)
+                    .ToArray();
+            }
 
             if (item.Chip != null && item.Chip.Any())
-                machine[Models.Internal.Machine.ChipKey] = item.Chip?.Select(ConvertToInternalModel)?.ToArray();
+            {
+                machine[Models.Internal.Machine.ChipKey] = item.Chip
+                    .Where(c => c != null)
+                    .Select(ConvertToInternalModel)
+                    .ToArray();
+            }
 
             if (item.Video != null)
-                machine[Models.Internal.Machine.VideoKey] = ConvertToInternalModel(item.Video);
+            {
+                machine[Models.Internal.Machine.VideoKey] = item.Video
+                    .Where(v => v != null)
+                    .Select(ConvertToInternalModel)
+                    .ToArray();
+            }
 
             if (item.Sound != null)
                 machine[Models.Internal.Machine.SoundKey] = ConvertToInternalModel(item.Sound);
@@ -551,7 +608,12 @@ namespace SabreTools.Serialization
                 machine[Models.Internal.Machine.InputKey] = ConvertToInternalModel(item.Input);
 
             if (item.DipSwitch != null && item.DipSwitch.Any())
-                machine[Models.Internal.Machine.DipSwitchKey] = item.DipSwitch?.Select(ConvertToInternalModel)?.ToArray();
+            {
+                machine[Models.Internal.Machine.DipSwitchKey] = item.DipSwitch
+                    .Where(d => d != null)
+                    .Select(ConvertToInternalModel)
+                    .ToArray();
+            }
 
             if (item.Driver != null)
                 machine[Models.Internal.Machine.DriverKey] = ConvertToInternalModel(item.Driver);

SabreTools.Serialization/DosCenter.Deserializer.cs

@@ -234,7 +234,12 @@ namespace SabreTools.Serialization
 
             var machines = item.Read<Models.Internal.Machine[]>(Models.Internal.MetadataFile.MachineKey);
             if (machines != null && machines.Any())
-                metadataFile.Game = machines.Select(ConvertMachineFromInternalModel).ToArray();
+            {
+                metadataFile.Game = machines
+                    .Where(m => m != null)
+                    .Select(ConvertMachineFromInternalModel)
+                    .ToArray();
+            }
 
             return metadataFile;
         }
@@ -242,11 +247,8 @@ namespace SabreTools.Serialization
         /// <summary>
         /// Convert from <cref="Models.Internal.Header"/> to <cref="Models.DosCenter.DosCenter"/>
         /// </summary>
-        private static Models.DosCenter.DosCenter? ConvertHeaderFromInternalModel(Models.Internal.Header? item)
+        private static Models.DosCenter.DosCenter ConvertHeaderFromInternalModel(Models.Internal.Header item)
         {
-            if (item == null)
-                return null;
-
             var dosCenter = new Models.DosCenter.DosCenter
             {
                 Name = item.ReadString(Models.Internal.Header.NameKey),
@@ -263,18 +265,21 @@ namespace SabreTools.Serialization
         /// <summary>
         /// Convert from <cref="Models.Internal.Machine"/> to <cref="Models.DosCenter.Game"/>
         /// </summary>
-        private static Game? ConvertMachineFromInternalModel(Models.Internal.Machine? item)
+        private static Game ConvertMachineFromInternalModel(Models.Internal.Machine item)
         {
-            if (item == null)
-                return null;
-
             var game = new Game
             {
                 Name = item.ReadString(Models.Internal.Machine.NameKey),
             };
 
             var roms = item.Read<Models.Internal.Rom[]>(Models.Internal.Machine.RomKey);
-            game.File = roms?.Select(ConvertFromInternalModel)?.ToArray();
+            if (roms != null && roms.Any())
+            {
+                game.File = roms
+                    .Where(r => r != null)
+                    .Select(ConvertFromInternalModel)
+                    .ToArray();
+            }
 
             return game;
         }
@@ -282,11 +287,8 @@ namespace SabreTools.Serialization
         /// <summary>
         /// Convert from <cref="Models.Internal.Rom"/> to <cref="Models.DosCenter.File"/>
         /// </summary>
-        private static Models.DosCenter.File? ConvertFromInternalModel(Models.Internal.Rom? item)
+        private static Models.DosCenter.File ConvertFromInternalModel(Models.Internal.Rom item)
         {
-            if (item == null)
-                return null;
-
             var file = new Models.DosCenter.File
             {
                 Name = item.ReadString(Models.Internal.Rom.NameKey),

SabreTools.Serialization/DosCenter.Serializer.cs

@@ -151,15 +151,23 @@ namespace SabreTools.Serialization
         /// <summary>
         /// Convert from <cref="Models.DosCenter.MetadataFile"/> to <cref="Models.Internal.MetadataFile"/>
         /// </summary>
-        public static Models.Internal.MetadataFile ConvertToInternalModel(MetadataFile item)
+        public static Models.Internal.MetadataFile? ConvertToInternalModel(MetadataFile? item)
         {
+            if (item == null)
+                return null;
+            
             var metadataFile = new Models.Internal.MetadataFile();
 
             if (item?.DosCenter != null)
                 metadataFile[Models.Internal.MetadataFile.HeaderKey] = ConvertHeaderToInternalModel(item.DosCenter);
 
             if (item?.Game != null && item.Game.Any())
-                metadataFile[Models.Internal.MetadataFile.MachineKey] = item.Game.Select(ConvertMachineToInternalModel).ToArray();
+            {
+                metadataFile[Models.Internal.MetadataFile.MachineKey] = item.Game
+                    .Where(g => g != null)
+                    .Select(ConvertMachineToInternalModel)
+                    .ToArray();
+            }
 
             return metadataFile;
         }
@@ -193,7 +201,12 @@ namespace SabreTools.Serialization
             };
 
             if (item.File != null && item.File.Any())
-                machine[Models.Internal.Machine.RomKey] = item.File.Select(ConvertToInternalModel).ToArray();
+            {
+                machine[Models.Internal.Machine.RomKey] = item.File
+                    .Where(f => f != null)
+                    .Select(ConvertToInternalModel)
+                    .ToArray();
+            }
 
             return machine;
         }

SabreTools.Serialization/EverdriveSMDB.Deserializer.cs

@@ -1,3 +1,4 @@
+using System;
 using System.Collections.Generic;
 using System.IO;
 using System.Linq;
@@ -91,7 +92,12 @@ namespace SabreTools.Serialization
 
             var machines = item.Read<Models.Internal.Machine[]>(Models.Internal.MetadataFile.MachineKey);
             if (machines != null && machines.Any())
-                metadataFile.Row = machines.SelectMany(ConvertMachineFromInternalModel).ToArray();
+            {
+                metadataFile.Row = machines
+                    .Where(m => m != null)
+                    .SelectMany(ConvertMachineFromInternalModel)
+                    .ToArray();
+            }
 
             return metadataFile;
         }
@@ -99,23 +105,23 @@ namespace SabreTools.Serialization
         /// <summary>
         /// Convert from <cref="Models.Internal.Machine"/> to an array of <cref="Models.EverdriveSMDB.Row"/>
         /// </summary>
-        private static Row[]? ConvertMachineFromInternalModel(Models.Internal.Machine item)
+        private static Row[] ConvertMachineFromInternalModel(Models.Internal.Machine item)
         {
-            if (item == null)
-                return null;
-
             var roms = item.Read<Models.Internal.Rom[]>(Models.Internal.Machine.RomKey);
-            return roms?.Select(ConvertFromInternalModel)?.ToArray();
+            if (roms == null || !roms.Any())
+                return Array.Empty<Row>();
+
+            return roms
+                .Where(r => r != null)
+                .Select(ConvertFromInternalModel)
+                .ToArray();
         }
 
         /// <summary>
         /// Convert from <cref="Models.Internal.Rom"/> to <cref="Models.EverdriveSMDB.Row"/>
         /// </summary>
-        private static Row? ConvertFromInternalModel(Models.Internal.Rom? item)
+        private static Row ConvertFromInternalModel(Models.Internal.Rom item)
         {
-            if (item == null)
-                return null;
-
             var row = new Row
             {
                 SHA256 = item.ReadString(Models.Internal.Rom.SHA256Key),

SabreTools.Serialization/EverdriveSMDB.Serializer.cs

@@ -88,15 +88,23 @@ namespace SabreTools.Serialization
         /// <summary>
         /// Convert from <cref="Models.EverdriveSMDB.MetadataFile"/> to <cref="Models.Internal.MetadataFile"/>
         /// </summary>
-        public static Models.Internal.MetadataFile ConvertToInternalModel(MetadataFile item)
+        public static Models.Internal.MetadataFile? ConvertToInternalModel(MetadataFile? item)
         {
+            if (item == null)
+                return null;
+            
             var metadataFile = new Models.Internal.MetadataFile
             {
                 [Models.Internal.MetadataFile.HeaderKey] = ConvertHeaderToInternalModel(item),
             };
 
             if (item?.Row != null && item.Row.Any())
-                metadataFile[Models.Internal.MetadataFile.MachineKey] = item.Row.Select(ConvertMachineToInternalModel).ToArray();
+            {
+                metadataFile[Models.Internal.MetadataFile.MachineKey] = item.Row
+                    .Where(r => r != null)
+                    .Select(ConvertMachineToInternalModel)
+                    .ToArray();
+            }
 
             return metadataFile;
         }

SabreTools.Serialization/Hashfile.Deserializer.cs

@@ -147,14 +147,82 @@ namespace SabreTools.Serialization
         /// <summary>
         /// Convert from <cref="Models.Internal.MetadataFile"/> to an array of <cref="Models.Hashfile.Hashfile"/>
         /// </summary>
-        public static Models.Hashfile.Hashfile[]? ConvertFromInternalModel(Models.Internal.MetadataFile? item, Hash hash)
+        /// <remarks>TODO: Add machine name prefixes to all items</remarks>
+        public static Models.Hashfile.Hashfile? ConvertFromInternalModel(Models.Internal.MetadataFile? item, Hash hash)
+        {
+            if (item == null)
+                return null;
+
+            var machines = item.Read<Models.Internal.Machine[]>(Models.Internal.MetadataFile.MachineKey);
+            if (machines == null || !machines.Any())
+                return null;
+
+            var hashfiles = machines
+                .Where(m => m != null)
+                .Select(machine => ConvertMachineFromInternalModel(machine, hash));
+
+            var sfvs = new List<SFV>();
+            var md5s = new List<MD5>();
+            var sha1s = new List<SHA1>();
+            var sha256s = new List<SHA256>();
+            var sha384s = new List<SHA384>();
+            var sha512s = new List<SHA512>();
+            var spamsums = new List<SpamSum>();
+
+            foreach (var hashfile in hashfiles)
+            {
+                if (hashfile.SFV != null && hashfile.SFV.Any())
+                    sfvs.AddRange(hashfile.SFV);
+                if (hashfile.MD5 != null && hashfile.MD5.Any())
+                    md5s.AddRange(hashfile.MD5);
+                if (hashfile.SHA1 != null && hashfile.SHA1.Any())
+                    sha1s.AddRange(hashfile.SHA1);
+                if (hashfile.SHA256 != null && hashfile.SHA256.Any())
+                    sha256s.AddRange(hashfile.SHA256);
+                if (hashfile.SHA384 != null && hashfile.SHA384.Any())
+                    sha384s.AddRange(hashfile.SHA384);
+                if (hashfile.SHA512 != null && hashfile.SHA512.Any())
+                    sha512s.AddRange(hashfile.SHA512);
+                if (hashfile.SpamSum != null && hashfile.SpamSum.Any())
+                    spamsums.AddRange(hashfile.SpamSum);
+            }
+
+            var hashfileItem = new Models.Hashfile.Hashfile();
+
+            if (sfvs.Any())
+                hashfileItem.SFV = sfvs.ToArray();
+            if (md5s.Any())
+                hashfileItem.MD5 = md5s.ToArray();
+            if (sha1s.Any())
+                hashfileItem.SHA1 = sha1s.ToArray();
+            if (sha256s.Any())
+                hashfileItem.SHA256 = sha256s.ToArray();
+            if (sha384s.Any())
+                hashfileItem.SHA384 = sha384s.ToArray();
+            if (sha512s.Any())
+                hashfileItem.SHA512 = sha512s.ToArray();
+            if (spamsums.Any())
+                hashfileItem.SpamSum = spamsums.ToArray();
+
+            return hashfileItem;
+        }
+
+        /// <summary>
+        /// Convert from <cref="Models.Internal.MetadataFile"/> to an array of <cref="Models.Hashfile.Hashfile"/>
+        /// </summary>
+        public static Models.Hashfile.Hashfile[]? ConvertArrayFromInternalModel(Models.Internal.MetadataFile? item, Hash hash)
         {
             if (item == null)
                 return null;
 
             var machines = item.Read<Models.Internal.Machine[]>(Models.Internal.MetadataFile.MachineKey);
             if (machines != null && machines.Any())
-                return machines.Select(machine => ConvertMachineFromInternalModel(machine, hash)).ToArray();
+            {
+                return machines
+                    .Where(m => m != null)
+                    .Select(machine => ConvertMachineFromInternalModel(machine, hash))
+                    .ToArray();
+            }
 
             return null;
         }
@@ -162,32 +230,64 @@ namespace SabreTools.Serialization
         /// <summary>
         /// Convert from <cref="Models.Internal.Machine"/> to <cref="Models.Hashfile.Hashfile"/>
         /// </summary>
-        private static Models.Hashfile.Hashfile? ConvertMachineFromInternalModel(Models.Internal.Machine? item, Hash hash)
+        private static Models.Hashfile.Hashfile ConvertMachineFromInternalModel(Models.Internal.Machine item, Hash hash)
         {
-            if (item == null)
-                return null;
-
             var roms = item.Read<Models.Internal.Rom[]>(Models.Internal.Machine.RomKey);
+            if (roms == null)
+                return new Models.Hashfile.Hashfile();
+
             return new Models.Hashfile.Hashfile
             {
-                SFV = hash == Hash.CRC ? roms?.Select(ConvertToSFV)?.ToArray() : null,
+                SFV = hash == Hash.CRC
-                MD5 = hash == Hash.MD5 ? roms?.Select(ConvertToMD5)?.ToArray() : null,
+                    ? roms
-                SHA1 = hash == Hash.SHA1 ? roms?.Select(ConvertToSHA1)?.ToArray() : null,
+                        .Where(r => r != null)
-                SHA256 = hash == Hash.SHA256 ? roms?.Select(ConvertToSHA256)?.ToArray() : null,
+                        .Select(ConvertToSFV)
-                SHA384 = hash == Hash.SHA384 ? roms?.Select(ConvertToSHA384)?.ToArray() : null,
+                        .ToArray()
-                SHA512 = hash == Hash.SHA512 ? roms?.Select(ConvertToSHA512)?.ToArray() : null,
+                    : null,
-                SpamSum = hash == Hash.SpamSum ? roms?.Select(ConvertToSpamSum)?.ToArray() : null,
+                MD5 = hash == Hash.MD5
+                    ? roms
+                        .Where(r => r != null)
+                        .Select(ConvertToMD5)
+                        .ToArray()
+                    : null,
+                SHA1 = hash == Hash.SHA1
+                    ? roms
+                        .Where(r => r != null)
+                        .Select(ConvertToSHA1)
+                        .ToArray()
+                    : null,
+                SHA256 = hash == Hash.SHA256
+                    ? roms
+                        .Where(r => r != null)
+                        .Select(ConvertToSHA256)
+                        .ToArray()
+                    : null,
+                SHA384 = hash == Hash.SHA384
+                    ? roms
+                        .Where(r => r != null)
+                        .Select(ConvertToSHA384)
+                        .ToArray()
+                    : null,
+                SHA512 = hash == Hash.SHA512
+                    ? roms
+                        .Where(r => r != null)
+                        .Select(ConvertToSHA512)
+                        .ToArray()
+                    : null,
+                SpamSum = hash == Hash.SpamSum
+                    ? roms
+                        .Where(r => r != null)
+                        .Select(ConvertToSpamSum)
+                        .ToArray()
+                    : null,
             };
         }
 
         /// <summary>
         /// Convert from <cref="Models.Internal.Rom"/> to <cref="Models.Hashfile.MD5"/>
         /// </summary>
-        private static MD5? ConvertToMD5(Models.Internal.Rom? item)
+        private static MD5 ConvertToMD5(Models.Internal.Rom item)
         {
-            if (item == null)
-                return null;
-
             var md5 = new MD5
             {
                 Hash = item.ReadString(Models.Internal.Rom.MD5Key),
@@ -199,11 +299,8 @@ namespace SabreTools.Serialization
         /// <summary>
         /// Convert from <cref="Models.Internal.Rom"/> to <cref="Models.Hashfile.SFV"/>
         /// </summary>
-        private static SFV? ConvertToSFV(Models.Internal.Rom? item)
+        private static SFV ConvertToSFV(Models.Internal.Rom item)
         {
-            if (item == null)
-                return null;
-
             var sfv = new SFV
             {
                 File = item.ReadString(Models.Internal.Rom.NameKey),
@@ -215,11 +312,8 @@ namespace SabreTools.Serialization
         /// <summary>
         /// Convert from <cref="Models.Internal.Rom"/> to <cref="Models.Hashfile.SHA1"/>
         /// </summary>
-        private static SHA1? ConvertToSHA1(Models.Internal.Rom? item)
+        private static SHA1 ConvertToSHA1(Models.Internal.Rom item)
         {
-            if (item == null)
-                return null;
-
             var sha1 = new SHA1
             {
                 Hash = item.ReadString(Models.Internal.Rom.SHA1Key),
@@ -231,11 +325,8 @@ namespace SabreTools.Serialization
         /// <summary>
         /// Convert from <cref="Models.Internal.Rom"/> to <cref="Models.Hashfile.SHA256"/>
         /// </summary>
-        private static SHA256? ConvertToSHA256(Models.Internal.Rom? item)
+        private static SHA256 ConvertToSHA256(Models.Internal.Rom item)
         {
-            if (item == null)
-                return null;
-
             var sha256 = new SHA256
             {
                 Hash = item.ReadString(Models.Internal.Rom.SHA256Key),
@@ -247,11 +338,8 @@ namespace SabreTools.Serialization
         /// <summary>
         /// Convert from <cref="Models.Internal.Rom"/> to <cref="Models.Hashfile.SHA384"/>
         /// </summary>
-        private static SHA384? ConvertToSHA384(Models.Internal.Rom? item)
+        private static SHA384 ConvertToSHA384(Models.Internal.Rom item)
         {
-            if (item == null)
-                return null;
-
             var sha384 = new SHA384
             {
                 Hash = item.ReadString(Models.Internal.Rom.SHA384Key),
@@ -263,11 +351,8 @@ namespace SabreTools.Serialization
         /// <summary>
         /// Convert from <cref="Models.Internal.Rom"/> to <cref="Models.Hashfile.SHA512"/>
         /// </summary>
-        private static SHA512? ConvertToSHA512(Models.Internal.Rom? item)
+        private static SHA512 ConvertToSHA512(Models.Internal.Rom item)
         {
-            if (item == null)
-                return null;
-
             var sha512 = new SHA512
             {
                 Hash = item.ReadString(Models.Internal.Rom.SHA512Key),
@@ -279,11 +364,8 @@ namespace SabreTools.Serialization
         /// <summary>
         /// Convert from <cref="Models.Internal.Rom"/> to <cref="Models.Hashfile.SpamSum"/>
         /// </summary>
-        private static SpamSum? ConvertToSpamSum(Models.Internal.Rom? item)
+        private static SpamSum ConvertToSpamSum(Models.Internal.Rom item)
         {
-            if (item == null)
-                return null;
-
             var spamsum = new SpamSum
             {
                 Hash = item.ReadString(Models.Internal.Rom.SpamSumKey),

SabreTools.Serialization/Hashfile.Serializer.cs

@@ -223,8 +223,11 @@ namespace SabreTools.Serialization
         /// <summary>
         /// Convert from <cref="Models.Hashfile.Hashfile"/> to <cref="Models.Internal.MetadataFile"/>
         /// </summary>
-        public static Models.Internal.MetadataFile ConvertToInternalModel(Models.Hashfile.Hashfile item)
+        public static Models.Internal.MetadataFile? ConvertToInternalModel(Models.Hashfile.Hashfile? item)
         {
+            if (item == null)
+                return null;
+            
             var metadataFile = new Models.Internal.MetadataFile
             {
                 [Models.Internal.MetadataFile.HeaderKey] = ConvertHeaderToInternalModel(item),

SabreTools.Serialization/Internal.cs

@@ -1,3 +1,4 @@
+using System;
 using System.Collections.Generic;
 using System.Linq;
 using SabreTools.Models.Internal;
@@ -6,6 +7,31 @@ namespace SabreTools.Serialization
 {
     public class Internal
     {
+        /// <summary>
+        /// Extract nested items from a Dump
+        /// </summary>
+        public static DatItem[]? ExtractItems(Dump? item)
+        {
+            if (item == null)
+                return null;
+
+            var datItems = new List<DatItem>();
+
+            var rom = item.Read<Rom>(Dump.RomKey);
+            if (rom != null)
+                datItems.Add(rom);
+
+            var megaRom = item.Read<Rom>(Dump.MegaRomKey);
+            if (megaRom != null)
+                datItems.Add(megaRom);
+
+            var sccPlusCart = item.Read<Rom>(Dump.SCCPlusCartKey);
+            if (sccPlusCart != null)
+                datItems.Add(sccPlusCart);
+
+            return datItems.ToArray();
+        }
+
         /// <summary>
         /// Extract nested items from a Part
         /// </summary>
@@ -22,15 +48,26 @@ namespace SabreTools.Serialization
 
             var dataAreas = item.Read<DataArea[]>(Part.DataAreaKey);
             if (dataAreas != null && dataAreas.Any())
-                datItems.AddRange(dataAreas.SelectMany(ExtractItems));
+            {
+                datItems.AddRange(dataAreas
+                    .Where(d => d != null)
+                    .SelectMany(ExtractItems));
+            }
 
             var diskAreas = item.Read<DiskArea[]>(Part.DiskAreaKey);
             if (diskAreas != null && diskAreas.Any())
-                datItems.AddRange(diskAreas.SelectMany(ExtractItems));
+            {
+                datItems.AddRange(diskAreas
+                    .Where(d => d != null)
+                    .SelectMany(ExtractItems));
+            }
 
             var dipSwitches = item.Read<DipSwitch[]>(Part.DipSwitchKey);
             if (dipSwitches != null && dipSwitches.Any())
-                datItems.AddRange(dipSwitches);
+            {
+                datItems.AddRange(dipSwitches
+                    .Where(d => d != null));
+            }
 
             return datItems.ToArray();
         }
@@ -38,23 +75,25 @@ namespace SabreTools.Serialization
         /// <summary>
         /// Extract nested items from a DataArea
         /// </summary>
-        private static Rom[]? ExtractItems(DataArea? item)
+        private static Rom[] ExtractItems(DataArea item)
         {
-            if (item == null)
+            var roms = item.Read<Rom[]>(DataArea.RomKey);
-                return null;
+            if (roms == null || !roms.Any())
+                return Array.Empty<Rom>();
 
-            return item.Read<Rom[]>(DataArea.RomKey);
+            return roms.ToArray();
         }
 
         /// <summary>
         /// Extract nested items from a DiskArea
         /// </summary>
-        private static Disk[]? ExtractItems(DiskArea? item)
+        private static Disk[] ExtractItems(DiskArea item)
         {
-            if (item == null)
+            var roms = item.Read<Disk[]>(DiskArea.DiskKey);
-                return null;
+            if (roms == null || !roms.Any())
+                return Array.Empty<Disk>();
 
-            return item.Read<Disk[]>(DiskArea.DiskKey);
+            return roms.ToArray();
         }
     }
 }

SabreTools.Serialization/Listrom.Deserializer.cs

@@ -202,7 +202,12 @@ namespace SabreTools.Serialization
 
             var machines = item.Read<Models.Internal.Machine[]>(Models.Internal.MetadataFile.MachineKey);
             if (machines != null && machines.Any())
-                metadataFile.Set = machines.Select(ConvertMachineFromInternalModel).ToArray();
+            {
+                metadataFile.Set = machines
+                    .Where(m => m != null)
+                    .Select(ConvertMachineFromInternalModel)
+                    .ToArray();
+            }
             
             return metadataFile;
         }
@@ -210,11 +215,8 @@ namespace SabreTools.Serialization
         /// <summary>
         /// Convert from <cref="Models.Internal.Machine"/> to <cref="Models.Listrom.Set"/>
         /// </summary>
-        private static Set? ConvertMachineFromInternalModel(Models.Internal.Machine? item)
+        private static Set ConvertMachineFromInternalModel(Models.Internal.Machine item)
         {
-            if (item == null)
-                return null;
-
             var set = new Set();
             if (item.ReadString(Models.Internal.Machine.IsDeviceKey) == "yes")
                 set.Device = item.ReadString(Models.Internal.Machine.NameKey);
@@ -225,11 +227,13 @@ namespace SabreTools.Serialization
 
             var roms = item.Read<Models.Internal.Rom[]>(Models.Internal.Machine.RomKey);
             if (roms != null)
-                rowItems.AddRange(roms.Select(ConvertFromInternalModel));
+            {
+                rowItems.AddRange(roms.Where(r => r != null).Select(ConvertFromInternalModel));
+            }
 
             var disks = item.Read<Models.Internal.Disk[]>(Models.Internal.Machine.DiskKey);
             if (disks != null)
-                rowItems.AddRange(disks.Select(ConvertFromInternalModel));
+                rowItems.AddRange(disks.Where(d => d != null).Select(ConvertFromInternalModel));
 
             set.Row = rowItems.ToArray();
             return set;
@@ -238,11 +242,8 @@ namespace SabreTools.Serialization
         /// <summary>
         /// Convert from <cref="Models.Internal.Disk"/> to <cref="Models.Listrom.Row"/>
         /// </summary>
-        private static Row? ConvertFromInternalModel(Models.Internal.Disk? item)
+        private static Row ConvertFromInternalModel(Models.Internal.Disk item)
         {
-            if (item == null)
-                return null;
-            
             var row = new Row
             {
                 Name = item.ReadString(Models.Internal.Disk.NameKey),
@@ -261,11 +262,8 @@ namespace SabreTools.Serialization
         /// <summary>
         /// Convert from <cref="Models.Internal.Rom"/> to <cref="Models.Listrom.Row"/>
         /// </summary>
-        private static Row? ConvertFromInternalModel(Models.Internal.Rom? item)
+        private static Row ConvertFromInternalModel(Models.Internal.Rom item)
         {
-            if (item == null)
-                return null;
-            
             var row = new Row
             {
                 Name = item.ReadString(Models.Internal.Rom.NameKey),

SabreTools.Serialization/Listrom.Serializer.cs

@@ -182,15 +182,23 @@ namespace SabreTools.Serialization
         /// <summary>
         /// Convert from <cref="Models.Listrom.MetadataFile"/> to <cref="Models.Internal.MetadataFile"/>
         /// </summary>
-        public static Models.Internal.MetadataFile ConvertToInternalModel(MetadataFile item)
+        public static Models.Internal.MetadataFile? ConvertToInternalModel(MetadataFile? item)
         {
+            if (item == null)
+                return null;
+            
             var metadataFile = new Models.Internal.MetadataFile
             {
                 [Models.Internal.MetadataFile.HeaderKey] = ConvertHeaderToInternalModel(item),
             };
 
             if (item?.Set != null && item.Set.Any())
-                metadataFile[Models.Internal.MetadataFile.MachineKey] = item.Set.Select(ConvertMachineToInternalModel).ToArray();
+            {
+                metadataFile[Models.Internal.MetadataFile.MachineKey] = item.Set
+                    .Where(s => s != null)
+                    .Select(ConvertMachineToInternalModel)
+                    .ToArray();
+            }
 
             return metadataFile;
         }

SabreTools.Serialization/Listxml.Deserializer.cs

@@ -11,7 +11,7 @@ namespace SabreTools.Serialization
         #region Internal
 
         /// <summary>
-        /// Convert from <cref="Models.Internal.MetadataFile"/> to <cref="Models.Listxml.M1"/>
+        /// Convert from <cref="Models.Internal.Models.Internal.MetadataFile"/> to <cref="Models.Listxml.M1"/>
         /// </summary>
         public static M1? ConvertM1FromInternalModel(Models.Internal.MetadataFile? item)
         {
@@ -23,13 +23,18 @@ namespace SabreTools.Serialization
 
             var machines = item.Read<Models.Internal.Machine[]>(Models.Internal.MetadataFile.MachineKey);
             if (machines != null && machines.Any())
-                m1.Game = machines.Select(ConvertMachineFromInternalModel).ToArray();
+            {
+                m1.Game = machines
+                    .Where(m => m != null)
+                    .Select(ConvertMachineFromInternalModel)
+                    .ToArray();
+            }
 
             return m1;
         }
 
         /// <summary>
-        /// Convert from <cref="Models.Internal.MetadataFile"/> to <cref="Models.Listxml.Mame"/>
+        /// Convert from <cref="Models.Internal.Models.Internal.MetadataFile"/> to <cref="Models.Listxml.Mame"/>
         /// </summary>
         public static Mame? ConvertMameFromInternalModel(Models.Internal.MetadataFile? item)
         {
@@ -41,19 +46,21 @@ namespace SabreTools.Serialization
 
             var machines = item.Read<Models.Internal.Machine[]>(Models.Internal.MetadataFile.MachineKey);
             if (machines != null && machines.Any())
-                mame.Game = machines.Select(ConvertMachineFromInternalModel).ToArray();
+            {
+                mame.Game = machines
+                    .Where(m => m != null)
+                    .Select(ConvertMachineFromInternalModel)
+                    .ToArray();
+            }
 
             return mame;
         }
 
         /// <summary>
-        /// Convert from <cref="Models.Internal.Header"/> to <cref="Models.Listxml.M1"/>
+        /// Convert from <cref="Models.Internal.Models.Internal.Header"/> to <cref="Models.Listxml.M1"/>
         /// </summary>
-        private static M1? ConvertM1FromInternalModel(Models.Internal.Header? item)
+        private static M1 ConvertM1FromInternalModel(Models.Internal.Header item)
         {
-            if (item == null)
-                return null;
-
             var m1 = new M1
             {
                 Version = item.ReadString(Models.Internal.Header.VersionKey),
@@ -62,13 +69,10 @@ namespace SabreTools.Serialization
         }
 
         /// <summary>
-        /// Convert from <cref="Models.Internal.Header"/> to <cref="Models.Listxml.Mame"/>
+        /// Convert from <cref="Models.Internal.Models.Internal.Header"/> to <cref="Models.Listxml.Mame"/>
         /// </summary>
-        private static Mame? ConvertMameFromInternalModel(Models.Internal.Header? item)
+        private static Mame ConvertMameFromInternalModel(Models.Internal.Header item)
         {
-            if (item == null)
-                return null;
-
             var mame = new Mame
             {
                 Build = item.ReadString(Models.Internal.Header.BuildKey),
@@ -80,13 +84,10 @@ namespace SabreTools.Serialization
         }
 
         /// <summary>
-        /// Convert from <cref="Models.Internal.Machine"/> to <cref="Models.Listxml.GameBase"/>
+        /// Convert from <cref="Models.Internal.Models.Internal.Machine"/> to <cref="Models.Listxml.GameBase"/>
         /// </summary>
-        private static GameBase? ConvertMachineFromInternalModel(Models.Internal.Machine? item)
+        private static GameBase ConvertMachineFromInternalModel(Models.Internal.Machine item)
         {
-            if (item == null)
-                return null;
-
             var machine = new Machine
             {
                 Name = item.ReadString(Models.Internal.Machine.NameKey),
@@ -105,76 +106,178 @@ namespace SabreTools.Serialization
             };
 
             var biosSets = item.Read<Models.Internal.BiosSet[]>(Models.Internal.Machine.BiosSetKey);
-            machine.BiosSet = biosSets?.Select(ConvertFromInternalModel)?.ToArray();
+            if (biosSets != null && biosSets.Any())
+            {
+                machine.BiosSet = biosSets
+                    .Where(b => b != null)
+                    .Select(ConvertFromInternalModel)
+                    .ToArray();
+            }
 
             var roms = item.Read<Models.Internal.Rom[]>(Models.Internal.Machine.RomKey);
-            machine.Rom = roms?.Select(ConvertFromInternalModel)?.ToArray();
+            if (roms != null && roms.Any())
+            {
+                machine.Rom = roms
+                    .Where(r => r != null)
+                    .Select(ConvertFromInternalModel)
+                    .ToArray();
+            }
 
             var disks = item.Read<Models.Internal.Disk[]>(Models.Internal.Machine.DiskKey);
-            machine.Disk = disks?.Select(ConvertFromInternalModel)?.ToArray();
+            if (disks != null && disks.Any())
+            {
+                machine.Disk = disks
+                    .Where(d => d != null)
+                    .Select(ConvertFromInternalModel)
+                    .ToArray();
+            }
 
             var deviceRefs = item.Read<Models.Internal.DeviceRef[]>(Models.Internal.Machine.DeviceRefKey);
-            machine.DeviceRef = deviceRefs?.Select(ConvertFromInternalModel)?.ToArray();
+            if (deviceRefs != null && deviceRefs.Any())
+            {
+                machine.DeviceRef = deviceRefs
+                    .Where(d => d != null)
+                    .Select(ConvertFromInternalModel)
+                    .ToArray();
+            }
 
             var samples = item.Read<Models.Internal.Sample[]>(Models.Internal.Machine.SampleKey);
-            machine.Sample = samples?.Select(ConvertFromInternalModel)?.ToArray();
+            if (samples != null && samples.Any())
+            {
+                machine.Sample = samples
+                    .Where(s => s != null)
+                    .Select(ConvertFromInternalModel)
+                    .ToArray();
+            }
 
             var chips = item.Read<Models.Internal.Chip[]>(Models.Internal.Machine.ChipKey);
-            machine.Chip = chips?.Select(ConvertFromInternalModel)?.ToArray();
+            if (chips != null && chips.Any())
+            {
+                machine.Chip = chips
+                    .Where(c => c != null)
+                    .Select(ConvertFromInternalModel)
+                    .ToArray();
+            }
 
             var displays = item.Read<Models.Internal.Display[]>(Models.Internal.Machine.DisplayKey);
-            machine.Display = displays?.Select(ConvertFromInternalModel)?.ToArray();
+            if (displays != null && displays.Any())
+            {
+                machine.Display = displays
+                    .Where(d => d != null)
+                    .Select(ConvertFromInternalModel)
+                    .ToArray();
+            }
 
             var videos = item.Read<Models.Internal.Video[]>(Models.Internal.Machine.VideoKey);
-            machine.Video = videos?.Select(ConvertFromInternalModel)?.ToArray();
+            if (videos != null && videos.Any())
+            {
+                machine.Video = videos
+                    .Where(d => d != null)
+                    .Select(ConvertFromInternalModel)
+                    .ToArray();
+            }
 
             var sound = item.Read<Models.Internal.Sound>(Models.Internal.Machine.SoundKey);
-            machine.Sound = ConvertFromInternalModel(sound);
+            if (sound != null)
+                machine.Sound = ConvertFromInternalModel(sound);
 
             var input = item.Read<Models.Internal.Input>(Models.Internal.Machine.InputKey);
-            machine.Input = ConvertFromInternalModel(input);
+            if (input != null)
+                machine.Input = ConvertFromInternalModel(input);
 
             var dipSwitches = item.Read<Models.Internal.DipSwitch[]>(Models.Internal.Machine.DipSwitchKey);
-            machine.DipSwitch = dipSwitches?.Select(ConvertFromInternalModel)?.ToArray();
+            if (dipSwitches != null && dipSwitches.Any())
+            {
+                machine.DipSwitch = dipSwitches
+                    .Where(d => d != null)
+                    .Select(ConvertFromInternalModel)
+                    .ToArray();
+            }
 
             var configurations = item.Read<Models.Internal.Configuration[]>(Models.Internal.Machine.ConfigurationKey);
-            machine.Configuration = configurations?.Select(ConvertFromInternalModel)?.ToArray();
+            if (configurations != null && configurations.Any())
+            {
+                machine.Configuration = configurations
+                    .Where(d => d != null)
+                    .Select(ConvertFromInternalModel)
+                    .ToArray();
+            }
 
             var ports = item.Read<Models.Internal.Port[]>(Models.Internal.Machine.PortKey);
-            machine.Port = ports?.Select(ConvertFromInternalModel)?.ToArray();
+            if (ports != null && ports.Any())
+            {
+                machine.Port = ports
+                    .Where(d => d != null)
+                    .Select(ConvertFromInternalModel)
+                    .ToArray();
+            }
 
             var adjusters = item.Read<Models.Internal.Adjuster[]>(Models.Internal.Machine.AdjusterKey);
-            machine.Adjuster = adjusters?.Select(ConvertFromInternalModel)?.ToArray();
+            if (adjusters != null && adjusters.Any())
+            {
+                machine.Adjuster = adjusters
+                    .Where(d => d != null)
+                    .Select(ConvertFromInternalModel)
+                    .ToArray();
+            }
 
             var driver = item.Read<Models.Internal.Driver>(Models.Internal.Machine.DriverKey);
-            machine.Driver = ConvertFromInternalModel(driver);
+            if (driver != null)
+                machine.Driver = ConvertFromInternalModel(driver);
 
             var features = item.Read<Models.Internal.Feature[]>(Models.Internal.Machine.FeatureKey);
-            machine.Feature = features?.Select(ConvertFromInternalModel)?.ToArray();
+            if (features != null && features.Any())
+            {
+                machine.Feature = features
+                    .Where(d => d != null)
+                    .Select(ConvertFromInternalModel)
+                    .ToArray();
+            }
 
             var devices = item.Read<Models.Internal.Device[]>(Models.Internal.Machine.DeviceKey);
-            machine.Device = devices?.Select(ConvertFromInternalModel)?.ToArray();
+            if (devices != null && devices.Any())
+            {
+                machine.Device = devices
+                    .Where(d => d != null)
+                    .Select(ConvertFromInternalModel)
+                    .ToArray();
+            }
 
             var slots = item.Read<Models.Internal.Slot[]>(Models.Internal.Machine.SlotKey);
-            machine.Slot = slots?.Select(ConvertFromInternalModel)?.ToArray();
+            if (slots != null && slots.Any())
+            {
+                machine.Slot = slots
+                    .Where(d => d != null)
+                    .Select(ConvertFromInternalModel)
+                    .ToArray();
+            }
 
             var softwareLists = item.Read<Models.Internal.SoftwareList[]>(Models.Internal.Machine.SoftwareListKey);
-            machine.SoftwareList = softwareLists?.Select(ConvertFromInternalModel)?.ToArray();
+            if (softwareLists != null && softwareLists.Any())
+            {
+                machine.SoftwareList = softwareLists
+                    .Where(d => d != null)
+                    .Select(ConvertFromInternalModel)
+                    .ToArray();
+            }
 
             var ramOptions = item.Read<Models.Internal.RamOption[]>(Models.Internal.Machine.RamOptionKey);
-            machine.RamOption = ramOptions?.Select(ConvertFromInternalModel)?.ToArray();
+            if (ramOptions != null && ramOptions.Any())
+            {
+                machine.RamOption = ramOptions
+                    .Where(d => d != null)
+                    .Select(ConvertFromInternalModel)
+                    .ToArray();
+            }
 
             return machine;
         }
 
         /// <summary>
-        /// Convert from <cref="Models.Internal.Adjuster"/> to <cref="Models.Listxml.Adjuster"/>
+        /// Convert from <cref="Models.Internal.Models.Internal.Adjuster"/> to <cref="Models.Listxml.Adjuster"/>
         /// </summary>
-        private static Adjuster? ConvertFromInternalModel(Models.Internal.Adjuster? item)
+        private static Adjuster ConvertFromInternalModel(Models.Internal.Adjuster item)
         {
-            if (item == null)
-                return null;
-
             var adjuster = new Adjuster
             {
                 Name = item.ReadString(Models.Internal.Adjuster.NameKey),
@@ -182,19 +285,17 @@ namespace SabreTools.Serialization
             };
 
             var condition = item.Read<Models.Internal.Condition>(Models.Internal.Adjuster.ConditionKey);
-            adjuster.Condition = ConvertFromInternalModel(condition);
+            if (condition != null)
+                adjuster.Condition = ConvertFromInternalModel(condition);
 
             return adjuster;
         }
 
         /// <summary>
-        /// Convert from <cref="Models.Internal.Analog"/> to <cref="Models.Listxml.Analog"/>
+        /// Convert from <cref="Models.Internal.Models.Internal.Analog"/> to <cref="Models.Listxml.Analog"/>
         /// </summary>
-        private static Analog? ConvertFromInternalModel(Models.Internal.Analog? item)
+        private static Analog ConvertFromInternalModel(Models.Internal.Analog item)
         {
-            if (item == null)
-                return null;
-
             var analog = new Analog
             {
                 Mask = item.ReadString(Models.Internal.Analog.MaskKey),
@@ -203,13 +304,10 @@ namespace SabreTools.Serialization
         }
 
         /// <summary>
-        /// Convert from <cref="Models.Internal.BiosSet"/> to <cref="Models.Listxml.BiosSet"/>
+        /// Convert from <cref="Models.Internal.Models.Internal.BiosSet"/> to <cref="Models.Listxml.BiosSet"/>
         /// </summary>
-        private static BiosSet? ConvertFromInternalModel(Models.Internal.BiosSet? item)
+        private static BiosSet ConvertFromInternalModel(Models.Internal.BiosSet item)
         {
-            if (item == null)
-                return null;
-
             var biosset = new BiosSet
             {
                 Name = item.ReadString(Models.Internal.BiosSet.NameKey),
@@ -220,13 +318,10 @@ namespace SabreTools.Serialization
         }
 
         /// <summary>
-        /// Convert from <cref="Models.Internal.Chip"/> to <cref="Models.Listxml.Chip"/>
+        /// Convert from <cref="Models.Internal.Models.Internal.Chip"/> to <cref="Models.Listxml.Chip"/>
         /// </summary>
-        private static Chip? ConvertFromInternalModel(Models.Internal.Chip? item)
+        private static Chip ConvertFromInternalModel(Models.Internal.Chip item)
         {
-            if (item == null)
-                return null;
-
             var chip = new Chip
             {
                 Name = item.ReadString(Models.Internal.Chip.NameKey),
@@ -239,13 +334,10 @@ namespace SabreTools.Serialization
         }
 
         /// <summary>
-        /// Convert from <cref="Models.Internal.Condition"/> to <cref="Models.Listxml.Condition"/>
+        /// Convert from <cref="Models.Internal.Models.Internal.Condition"/> to <cref="Models.Listxml.Condition"/>
         /// </summary>
-        private static Condition? ConvertFromInternalModel(Models.Internal.Condition? item)
+        private static Condition ConvertFromInternalModel(Models.Internal.Condition item)
         {
-            if (item == null)
-                return null;
-
             var condition = new Condition
             {
                 Tag = item.ReadString(Models.Internal.Condition.TagKey),
@@ -257,13 +349,10 @@ namespace SabreTools.Serialization
         }
 
         /// <summary>
-        /// Convert from <cref="Models.Internal.Configuration"/> to <cref="Models.Listxml.Configuration"/>
+        /// Convert from <cref="Models.Internal.Models.Internal.Configuration"/> to <cref="Models.Listxml.Configuration"/>
         /// </summary>
-        private static Configuration? ConvertFromInternalModel(Models.Internal.Configuration? item)
+        private static Configuration ConvertFromInternalModel(Models.Internal.Configuration item)
         {
-            if (item == null)
-                return null;
-
             var configuration = new Configuration
             {
                 Name = item.ReadString(Models.Internal.Configuration.NameKey),
@@ -272,25 +361,35 @@ namespace SabreTools.Serialization
             };
 
             var condition = item.Read<Models.Internal.Condition>(Models.Internal.Configuration.ConditionKey);
-            configuration.Condition = ConvertFromInternalModel(condition);
+            if (condition != null)
+                configuration.Condition = ConvertFromInternalModel(condition);
 
             var confLocations = item.Read<Models.Internal.ConfLocation[]>(Models.Internal.Configuration.ConfLocationKey);
-            configuration.ConfLocation = confLocations?.Select(ConvertFromInternalModel)?.ToArray();
+            if (confLocations != null && confLocations.Any())
+            {
+                configuration.ConfLocation = confLocations
+                    .Where(c => c != null)
+                    .Select(ConvertFromInternalModel)
+                    .ToArray();
+            }
 
             var confSettings = item.Read<Models.Internal.ConfSetting[]>(Models.Internal.Configuration.ConfSettingKey);
-            configuration.ConfSetting = confSettings?.Select(ConvertFromInternalModel)?.ToArray();
+            if (confSettings != null && confSettings.Any())
+            {
+                configuration.ConfSetting = confSettings
+                    .Where(c => c != null)
+                    .Select(ConvertFromInternalModel)
+                    .ToArray();
+            }
 
             return configuration;
         }
 
         /// <summary>
-        /// Convert from <cref="Models.Internal.ConfLocation"/> to <cref="Models.Listxml.ConfLocation"/>
+        /// Convert from <cref="Models.Internal.Models.Internal.ConfLocation"/> to <cref="Models.Listxml.ConfLocation"/>
         /// </summary>
-        private static ConfLocation? ConvertFromInternalModel(Models.Internal.ConfLocation? item)
+        private static ConfLocation ConvertFromInternalModel(Models.Internal.ConfLocation item)
         {
-            if (item == null)
-                return null;
-
             var confLocation = new ConfLocation
             {
                 Name = item.ReadString(Models.Internal.ConfLocation.NameKey),
@@ -301,13 +400,10 @@ namespace SabreTools.Serialization
         }
 
         /// <summary>
-        /// Convert from <cref="Models.Internal.ConfSetting"/> to <cref="Models.Listxml.ConfSetting"/>
+        /// Convert from <cref="Models.Internal.Models.Internal.ConfSetting"/> to <cref="Models.Listxml.ConfSetting"/>
         /// </summary>
-        private static ConfSetting? ConvertFromInternalModel(Models.Internal.ConfSetting? item)
+        private static ConfSetting ConvertFromInternalModel(Models.Internal.ConfSetting item)
         {
-            if (item == null)
-                return null;
-
             var confSetting = new ConfSetting
             {
                 Name = item.ReadString(Models.Internal.ConfSetting.NameKey),
@@ -316,19 +412,17 @@ namespace SabreTools.Serialization
             };
 
             var condition = item.Read<Models.Internal.Condition>(Models.Internal.ConfSetting.ConditionKey);
-            confSetting.Condition = ConvertFromInternalModel(condition);
+            if (condition != null)
+                confSetting.Condition = ConvertFromInternalModel(condition);
 
             return confSetting;
         }
 
         /// <summary>
-        /// Convert from <cref="Models.Internal.Control"/> to <cref="Models.Listxml.Control"/>
+        /// Convert from <cref="Models.Internal.Models.Internal.Control"/> to <cref="Models.Listxml.Control"/>
         /// </summary>
-        private static Control? ConvertFromInternalModel(Models.Internal.Control? item)
+        private static Control ConvertFromInternalModel(Models.Internal.Control item)
         {
-            if (item == null)
-                return null;
-
             var control = new Control
             {
                 Type = item.ReadString(Models.Internal.Control.TypeKey),
@@ -348,13 +442,10 @@ namespace SabreTools.Serialization
         }
 
         /// <summary>
-        /// Convert from <cref="Models.Internal.Device"/> to <cref="Models.Listxml.Device"/>
+        /// Convert from <cref="Models.Internal.Models.Internal.Device"/> to <cref="Models.Listxml.Device"/>
         /// </summary>
-        private static Device? ConvertFromInternalModel(Models.Internal.Device? item)
+        private static Device ConvertFromInternalModel(Models.Internal.Device item)
         {
-            if (item == null)
-                return null;
-
             var device = new Device
             {
                 Type = item.ReadString(Models.Internal.Device.TypeKey),
@@ -365,22 +456,26 @@ namespace SabreTools.Serialization
             };
 
             var instance = item.Read<Models.Internal.Instance>(Models.Internal.Device.InstanceKey);
-            device.Instance = ConvertFromInternalModel(instance);
+            if (instance != null)
+                device.Instance = ConvertFromInternalModel(instance);
 
             var extensions = item.Read<Models.Internal.Extension[]>(Models.Internal.Device.ExtensionKey);
-            device.Extension = extensions?.Select(ConvertFromInternalModel)?.ToArray();
+            if (extensions != null && extensions.Any())
+            {
+                device.Extension = extensions
+                    .Where(e => e != null)
+                    .Select(ConvertFromInternalModel)
+                    .ToArray();
+            }
 
             return device;
         }
 
         /// <summary>
-        /// Convert from <cref="DeviceRef"/> to <cref="Models.Listxml.DeviceRef"/>
+        /// Convert from <cref="Models.Internal.DeviceRef"/> to <cref="Models.Listxml.DeviceRef"/>
         /// </summary>
-        private static DeviceRef? ConvertFromInternalModel(Models.Internal.DeviceRef? item)
+        private static DeviceRef ConvertFromInternalModel(Models.Internal.DeviceRef item)
         {
-            if (item == null)
-                return null;
-
             var deviceRef = new DeviceRef
             {
                 Name = item.ReadString(Models.Internal.DeviceRef.NameKey),
@@ -389,13 +484,10 @@ namespace SabreTools.Serialization
         }
 
         /// <summary>
-        /// Convert from <cref="DipLocation"/> to <cref="Models.Listxml.DipLocation"/>
+        /// Convert from <cref="Models.Internal.DipLocation"/> to <cref="Models.Listxml.DipLocation"/>
         /// </summary>
-        private static DipLocation? ConvertFromInternalModel(Models.Internal.DipLocation? item)
+        private static DipLocation ConvertFromInternalModel(Models.Internal.DipLocation item)
         {
-            if (item == null)
-                return null;
-
             var dipLocation = new DipLocation
             {
                 Name = item.ReadString(Models.Internal.DipLocation.NameKey),
@@ -406,13 +498,10 @@ namespace SabreTools.Serialization
         }
 
         /// <summary>
-        /// Convert from <cref="DipSwitch"/> to <cref="Models.Listxml.DipSwitch"/>
+        /// Convert from <cref="Models.Internal.DipSwitch"/> to <cref="Models.Listxml.DipSwitch"/>
         /// </summary>
-        private static DipSwitch? ConvertFromInternalModel(Models.Internal.DipSwitch? item)
+        private static DipSwitch ConvertFromInternalModel(Models.Internal.DipSwitch item)
         {
-            if (item == null)
-                return null;
-
             var dipSwitch = new DipSwitch
             {
                 Name = item.ReadString(Models.Internal.DipSwitch.NameKey),
@@ -421,25 +510,35 @@ namespace SabreTools.Serialization
             };
 
             var condition = item.Read<Models.Internal.Condition>(Models.Internal.DipSwitch.ConditionKey);
-            dipSwitch.Condition = ConvertFromInternalModel(condition);
+            if (condition != null)
+                dipSwitch.Condition = ConvertFromInternalModel(condition);
 
             var dipLocations = item.Read<Models.Internal.DipLocation[]>(Models.Internal.DipSwitch.DipLocationKey);
-            dipSwitch.DipLocation = dipLocations?.Select(ConvertFromInternalModel)?.ToArray();
+            if (dipLocations != null && dipLocations.Any())
+            {
+                dipSwitch.DipLocation = dipLocations
+                    .Where(d => d != null)
+                    .Select(ConvertFromInternalModel)
+                    .ToArray();
+            }
 
             var dipValues = item.Read<Models.Internal.DipValue[]>(Models.Internal.DipSwitch.DipValueKey);
-            dipSwitch.DipValue = dipValues?.Select(ConvertFromInternalModel)?.ToArray();
+            if (dipValues != null && dipValues.Any())
+            {
+                dipSwitch.DipValue = dipValues
+                    .Where(d => d != null)
+                    .Select(ConvertFromInternalModel)
+                    .ToArray();
+            }
 
             return dipSwitch;
         }
 
         /// <summary>
-        /// Convert from <cref="DipValue"/> to <cref="Models.Listxml.DipValue"/>
+        /// Convert from <cref="Models.Internal.DipValue"/> to <cref="Models.Listxml.DipValue"/>
         /// </summary>
-        private static DipValue? ConvertFromInternalModel(Models.Internal.DipValue? item)
+        private static DipValue ConvertFromInternalModel(Models.Internal.DipValue item)
         {
-            if (item == null)
-                return null;
-
             var dipValue = new DipValue
             {
                 Name = item.ReadString(Models.Internal.DipValue.NameKey),
@@ -448,19 +547,17 @@ namespace SabreTools.Serialization
             };
 
             var condition = item.Read<Models.Internal.Condition>(Models.Internal.DipValue.ConditionKey);
-            dipValue.Condition = ConvertFromInternalModel(condition);
+            if (condition != null)
+                dipValue.Condition = ConvertFromInternalModel(condition);
 
             return dipValue;
         }
 
         /// <summary>
-        /// Convert from <cref="Disk"/> to <cref="Models.Listxml.Disk"/>
+        /// Convert from <cref="Models.Internal.Disk"/> to <cref="Models.Listxml.Disk"/>
         /// </summary>
-        private static Disk? ConvertFromInternalModel(Models.Internal.Disk? item)
+        private static Disk ConvertFromInternalModel(Models.Internal.Disk item)
         {
-            if (item == null)
-                return null;
-
             var disk = new Disk
             {
                 Name = item.ReadString(Models.Internal.Disk.NameKey),
@@ -477,13 +574,10 @@ namespace SabreTools.Serialization
         }
 
         /// <summary>
-        /// Convert from <cref="Display"/> to <cref="Models.Listxml.Display"/>
+        /// Convert from <cref="Models.Internal.Display"/> to <cref="Models.Listxml.Display"/>
         /// </summary>
-        private static Display? ConvertFromInternalModel(Models.Internal.Display? item)
+        private static Display ConvertFromInternalModel(Models.Internal.Display item)
         {
-            if (item == null)
-                return null;
-
             var display = new Display
             {
                 Tag = item.ReadString(Models.Internal.Display.TagKey),
@@ -505,13 +599,10 @@ namespace SabreTools.Serialization
         }
 
         /// <summary>
-        /// Convert from <cref="Driver"/> to <cref="Models.Listxml.Driver"/>
+        /// Convert from <cref="Models.Internal.Driver"/> to <cref="Models.Listxml.Driver"/>
         /// </summary>
-        private static Driver? ConvertFromInternalModel(Models.Internal.Driver? item)
+        private static Driver ConvertFromInternalModel(Models.Internal.Driver item)
         {
-            if (item == null)
-                return null;
-
             var driver = new Driver
             {
                 Status = item.ReadString(Models.Internal.Driver.StatusKey),
@@ -530,13 +621,10 @@ namespace SabreTools.Serialization
         }
 
         /// <summary>
-        /// Convert from <cref="Extension"/> to <cref="Models.Listxml.Extension"/>
+        /// Convert from <cref="Models.Internal.Extension"/> to <cref="Models.Listxml.Extension"/>
         /// </summary>
-        private static Extension? ConvertFromInternalModel(Models.Internal.Extension? item)
+        private static Extension ConvertFromInternalModel(Models.Internal.Extension item)
         {
-            if (item == null)
-                return null;
-
             var extension = new Extension
             {
                 Name = item.ReadString(Models.Internal.Extension.NameKey),
@@ -545,13 +633,10 @@ namespace SabreTools.Serialization
         }
 
         /// <summary>
-        /// Convert from <cref="Feature"/> to <cref="Models.Listxml.Feature"/>
+        /// Convert from <cref="Models.Internal.Feature"/> to <cref="Models.Listxml.Feature"/>
         /// </summary>
-        private static Feature? ConvertFromInternalModel(Models.Internal.Feature? item)
+        private static Feature ConvertFromInternalModel(Models.Internal.Feature item)
         {
-            if (item == null)
-                return null;
-
             var feature = new Feature
             {
                 Type = item.ReadString(Models.Internal.Feature.TypeKey),
@@ -562,13 +647,10 @@ namespace SabreTools.Serialization
         }
 
         /// <summary>
-        /// Convert from <cref="Input"/> to <cref="Models.Listxml.Input"/>
+        /// Convert from <cref="Models.Internal.Input"/> to <cref="Models.Listxml.Input"/>
         /// </summary>
-        private static Input? ConvertFromInternalModel(Models.Internal.Input? item)
+        private static Input ConvertFromInternalModel(Models.Internal.Input item)
         {
-            if (item == null)
-                return null;
-
             var input = new Input
             {
                 Service = item.ReadString(Models.Internal.Input.ServiceKey),
@@ -580,19 +662,22 @@ namespace SabreTools.Serialization
             };
 
             var controls = item.Read<Models.Internal.Control[]>(Models.Internal.Input.ControlKey);
-            input.Control = controls?.Select(ConvertFromInternalModel)?.ToArray();
+            if (controls != null && controls.Any())
+            {
+                input.Control = controls
+                    .Where(c => c != null)
+                    .Select(ConvertFromInternalModel)
+                    .ToArray();
+            }
 
             return input;
         }
 
         /// <summary>
-        /// Convert from <cref="Instance"/> to <cref="Models.Listxml.Instance"/>
+        /// Convert from <cref="Models.Internal.Instance"/> to <cref="Models.Listxml.Instance"/>
         /// </summary>
-        private static Instance? ConvertFromInternalModel(Models.Internal.Instance? item)
+        private static Instance ConvertFromInternalModel(Models.Internal.Instance item)
         {
-            if (item == null)
-                return null;
-
             var instance = new Instance
             {
                 Name = item.ReadString(Models.Internal.Instance.NameKey),
@@ -602,32 +687,32 @@ namespace SabreTools.Serialization
         }
 
         /// <summary>
-        /// Convert from <cref="Port"/> to <cref="Models.Listxml.Port"/>
+        /// Convert from <cref="Models.Internal.Port"/> to <cref="Models.Listxml.Port"/>
         /// </summary>
-        private static Port? ConvertFromInternalModel(Models.Internal.Port? item)
+        private static Port ConvertFromInternalModel(Models.Internal.Port item)
         {
-            if (item == null)
-                return null;
-
             var port = new Port
             {
                 Tag = item.ReadString(Models.Internal.Port.TagKey),
             };
 
             var analogs = item.Read<Models.Internal.Analog[]>(Models.Internal.Port.AnalogKey);
-            port.Analog = analogs?.Select(ConvertFromInternalModel)?.ToArray();
+            if (analogs != null && analogs.Any())
+            {
+                port.Analog = analogs
+                    .Where(a => a != null)
+                    .Select(ConvertFromInternalModel)
+                    .ToArray();
+            }
 
             return port;
         }
 
         /// <summary>
-        /// Convert from <cref="RamOption"/> to <cref="Models.Listxml.RamOption"/>
+        /// Convert from <cref="Models.Internal.RamOption"/> to <cref="Models.Listxml.RamOption"/>
         /// </summary>
-        private static RamOption? ConvertFromInternalModel(Models.Internal.RamOption? item)
+        private static RamOption ConvertFromInternalModel(Models.Internal.RamOption item)
         {
-            if (item == null)
-                return null;
-
             var ramOption = new RamOption
             {
                 Name = item.ReadString(Models.Internal.RamOption.NameKey),
@@ -637,13 +722,10 @@ namespace SabreTools.Serialization
         }
 
         /// <summary>
-        /// Convert from <cref="Rom"/> to <cref="Models.Listxml.Rom"/>
+        /// Convert from <cref="Models.Internal.Rom"/> to <cref="Models.Listxml.Rom"/>
         /// </summary>
-        private static Rom? ConvertFromInternalModel(Models.Internal.Rom? item)
+        private static Rom ConvertFromInternalModel(Models.Internal.Rom item)
         {
-            if (item == null)
-                return null;
-
             var rom = new Rom
             {
                 Name = item.ReadString(Models.Internal.Rom.NameKey),
@@ -663,13 +745,10 @@ namespace SabreTools.Serialization
         }
 
         /// <summary>
-        /// Convert from <cref="Sample"/> to <cref="Models.Listxml.Sample"/>
+        /// Convert from <cref="Models.Internal.Sample"/> to <cref="Models.Listxml.Sample"/>
         /// </summary>
-        private static Sample? ConvertFromInternalModel(Models.Internal.Sample? item)
+        private static Sample ConvertFromInternalModel(Models.Internal.Sample item)
         {
-            if (item == null)
-                return null;
-
             var sample = new Sample
             {
                 Name = item.ReadString(Models.Internal.Sample.NameKey),
@@ -678,32 +757,32 @@ namespace SabreTools.Serialization
         }
 
         /// <summary>
-        /// Convert from <cref="Slot"/> to <cref="Models.Listxml.Slot"/>
+        /// Convert from <cref="Models.Internal.Slot"/> to <cref="Models.Listxml.Slot"/>
         /// </summary>
-        private static Slot? ConvertFromInternalModel(Models.Internal.Slot? item)
+        private static Slot ConvertFromInternalModel(Models.Internal.Slot item)
         {
-            if (item == null)
-                return null;
-
             var slot = new Slot
             {
                 Name = item.ReadString(Models.Internal.Slot.NameKey),
             };
 
             var slotOptions = item.Read<Models.Internal.SlotOption[]>(Models.Internal.Slot.SlotOptionKey);
-            slot.SlotOption = slotOptions?.Select(ConvertFromInternalModel)?.ToArray();
+            if (slotOptions != null && slotOptions.Any())
+            {
+                slot.SlotOption = slotOptions
+                    .Where(s => s != null)
+                    .Select(ConvertFromInternalModel)
+                    .ToArray();
+            }
 
             return slot;
         }
 
         /// <summary>
-        /// Convert from <cref="SlotOption"/> to <cref="Models.Listxml.SlotOption"/>
+        /// Convert from <cref="Models.Internal.SlotOption"/> to <cref="Models.Listxml.SlotOption"/>
         /// </summary>
-        private static SlotOption? ConvertFromInternalModel(Models.Internal.SlotOption? item)
+        private static SlotOption ConvertFromInternalModel(Models.Internal.SlotOption item)
         {
-            if (item == null)
-                return null;
-
             var slotOption = new SlotOption
             {
                 Name = item.ReadString(Models.Internal.SlotOption.NameKey),
@@ -714,13 +793,10 @@ namespace SabreTools.Serialization
         }
 
         /// <summary>
-        /// Convert from <cref="SoftwareList"/> to <cref="Models.Listxml.SoftwareList"/>
+        /// Convert from <cref="Models.Internal.SoftwareList"/> to <cref="Models.Listxml.SoftwareList"/>
         /// </summary>
-        private static SoftwareList? ConvertFromInternalModel(Models.Internal.SoftwareList? item)
+        private static SoftwareList ConvertFromInternalModel(Models.Internal.SoftwareList item)
         {
-            if (item == null)
-                return null;
-
             var softwareList = new SoftwareList
             {
                 Tag = item.ReadString(Models.Internal.SoftwareList.TagKey),
@@ -732,13 +808,10 @@ namespace SabreTools.Serialization
         }
 
         /// <summary>
-        /// Convert from <cref="Sound"/> to <cref="Models.Listxml.Sound"/>
+        /// Convert from <cref="Models.Internal.Sound"/> to <cref="Models.Listxml.Sound"/>
         /// </summary>
-        private static Sound? ConvertFromInternalModel(Models.Internal.Sound? item)
+        private static Sound ConvertFromInternalModel(Models.Internal.Sound item)
         {
-            if (item == null)
-                return null;
-
             var sound = new Sound
             {
                 Channels = item.ReadString(Models.Internal.Sound.ChannelsKey),
@@ -747,13 +820,10 @@ namespace SabreTools.Serialization
         }
 
         /// <summary>
-        /// Convert from <cref="Video"/> to <cref="Models.Listxml.Video"/>
+        /// Convert from <cref="Models.Internal.Video"/> to <cref="Models.Listxml.Video"/>
         /// </summary>
-        private static Video? ConvertFromInternalModel(Models.Internal.Video? item)
+        private static Video ConvertFromInternalModel(Models.Internal.Video item)
         {
-            if (item == null)
-                return null;
-
             var video = new Video
             {
                 Screen = item.ReadString(Models.Internal.Video.ScreenKey),

SabreTools.Serialization/Listxml.Serializer.cs

@@ -13,15 +13,23 @@ namespace SabreTools.Serialization
         /// <summary>
         /// Convert from <cref="Models.Listxml.M1"/> to <cref="Models.Internal.MetadataFile"/>
         /// </summary>
-        public static Models.Internal.MetadataFile ConvertToInternalModel(M1 item)
+        public static Models.Internal.MetadataFile? ConvertToInternalModel(M1? item)
         {
+            if (item == null)
+                return null;
+
             var metadataFile = new Models.Internal.MetadataFile
             {
                 [Models.Internal.MetadataFile.HeaderKey] = ConvertHeaderToInternalModel(item),
             };
 
             if (item?.Game != null && item.Game.Any())
-                metadataFile[Models.Internal.MetadataFile.MachineKey] = item.Game.Select(ConvertMachineToInternalModel).ToArray();
+            {
+                metadataFile[Models.Internal.MetadataFile.MachineKey] = item.Game
+                    .Where(g => g != null)
+                    .Select(ConvertMachineToInternalModel)
+                    .ToArray();
+            }
 
             return metadataFile;
         }
@@ -29,15 +37,23 @@ namespace SabreTools.Serialization
         /// <summary>
         /// Convert from <cref="Models.Listxml.Mame"/> to <cref="Models.Internal.MetadataFile"/>
         /// </summary>
-        public static Models.Internal.MetadataFile ConvertToInternalModel(Mame item)
+        public static Models.Internal.MetadataFile? ConvertToInternalModel(Mame? item)
         {
+            if (item == null)
+                return null;
+
             var metadataFile = new Models.Internal.MetadataFile
             {
                 [Models.Internal.MetadataFile.HeaderKey] = ConvertHeaderToInternalModel(item),
             };
 
             if (item?.Game != null && item.Game.Any())
-                metadataFile[Models.Internal.MetadataFile.MachineKey] = item.Game.Select(ConvertMachineToInternalModel).ToArray();
+            {
+                metadataFile[Models.Internal.MetadataFile.MachineKey] = item.Game
+                    .Where(g => g != null)
+                    .Select(ConvertMachineToInternalModel)
+                    .ToArray();
+            }
 
             return metadataFile;
         }
@@ -91,28 +107,68 @@ namespace SabreTools.Serialization
             };
 
             if (item.BiosSet != null && item.BiosSet.Any())
-                machine[Models.Internal.Machine.BiosSetKey] = item.BiosSet.Select(ConvertToInternalModel).ToArray();
+            {
+                machine[Models.Internal.Machine.BiosSetKey] = item.BiosSet
+                    .Where(b => b != null)
+                    .Select(ConvertToInternalModel)
+                    .ToArray();
+            }
 
             if (item.Rom != null && item.Rom.Any())
-                machine[Models.Internal.Machine.RomKey] = item.Rom.Select(ConvertToInternalModel).ToArray();
+            {
+                machine[Models.Internal.Machine.RomKey] = item.Rom
+                    .Where(r => r != null)
+                    .Select(ConvertToInternalModel)
+                    .ToArray();
+            }
 
             if (item.Disk != null && item.Disk.Any())
-                machine[Models.Internal.Machine.DiskKey] = item.Disk.Select(ConvertToInternalModel).ToArray();
+            {
+                machine[Models.Internal.Machine.DiskKey] = item.Disk
+                    .Where(d => d != null)
+                    .Select(ConvertToInternalModel)
+                    .ToArray();
+            }
 
             if (item.DeviceRef != null && item.DeviceRef.Any())
-                machine[Models.Internal.Machine.DeviceRefKey] = item.DeviceRef.Select(ConvertToInternalModel).ToArray();
+            {
+                machine[Models.Internal.Machine.DeviceRefKey] = item.DeviceRef
+                    .Where(d => d != null)
+                    .Select(ConvertToInternalModel)
+                    .ToArray();
+            }
 
             if (item.Sample != null && item.Sample.Any())
-                machine[Models.Internal.Machine.SampleKey] = item.Sample.Select(ConvertToInternalModel).ToArray();
+            {
+                machine[Models.Internal.Machine.SampleKey] = item.Sample
+                    .Where(s => s != null)
+                    .Select(ConvertToInternalModel)
+                    .ToArray();
+            }
 
             if (item.Chip != null && item.Chip.Any())
-                machine[Models.Internal.Machine.ChipKey] = item.Chip.Select(ConvertToInternalModel).ToArray();
+            {
+                machine[Models.Internal.Machine.ChipKey] = item.Chip
+                    .Where(c => c != null)
+                    .Select(ConvertToInternalModel)
+                    .ToArray();
+            }
 
             if (item.Display != null && item.Display.Any())
-                machine[Models.Internal.Machine.DisplayKey] = item.Display.Select(ConvertToInternalModel).ToArray();
+            {
+                machine[Models.Internal.Machine.DisplayKey] = item.Display
+                    .Where(d => d != null)
+                    .Select(ConvertToInternalModel)
+                    .ToArray();
+            }
 
             if (item.Video != null && item.Video.Any())
-                machine[Models.Internal.Machine.VideoKey] = item.Video.Select(ConvertToInternalModel).ToArray();
+            {
+                machine[Models.Internal.Machine.VideoKey] = item.Video
+                    .Where(v => v != null)
+                    .Select(ConvertToInternalModel)
+                    .ToArray();
+            }
 
             if (item.Sound != null)
                 machine[Models.Internal.Machine.SoundKey] = ConvertToInternalModel(item.Sound);
@@ -121,34 +177,79 @@ namespace SabreTools.Serialization
                 machine[Models.Internal.Machine.InputKey] = ConvertToInternalModel(item.Input);
 
             if (item.DipSwitch != null && item.DipSwitch.Any())
-                machine[Models.Internal.Machine.DipSwitchKey] = item.DipSwitch.Select(ConvertToInternalModel).ToArray();
+            {
+                machine[Models.Internal.Machine.DipSwitchKey] = item.DipSwitch
+                    .Where(d => d != null)
+                    .Select(ConvertToInternalModel)
+                    .ToArray();
+            }
 
             if (item.Configuration != null && item.Configuration.Any())
-                machine[Models.Internal.Machine.ConfigurationKey] = item.Configuration.Select(ConvertToInternalModel).ToArray();
+            {
+                machine[Models.Internal.Machine.ConfigurationKey] = item.Configuration
+                    .Where(c => c != null)
+                    .Select(ConvertToInternalModel)
+                    .ToArray();
+            }
 
             if (item.Port != null && item.Port.Any())
-                machine[Models.Internal.Machine.PortKey] = item.Port.Select(ConvertToInternalModel).ToArray();
+            {
+                machine[Models.Internal.Machine.PortKey] = item.Port
+                    .Where(p => p != null)
+                    .Select(ConvertToInternalModel)
+                    .ToArray();
+            }
 
             if (item.Adjuster != null && item.Adjuster.Any())
-                machine[Models.Internal.Machine.AdjusterKey] = item.Adjuster.Select(ConvertToInternalModel).ToArray();
+            {
+                machine[Models.Internal.Machine.AdjusterKey] = item.Adjuster
+                    .Where(a => a != null)
+                    .Select(ConvertToInternalModel)
+                    .ToArray();
+            }
 
             if (item.Driver != null)
                 machine[Models.Internal.Machine.DriverKey] = ConvertToInternalModel(item.Driver);
 
             if (item.Feature != null && item.Feature.Any())
-                machine[Models.Internal.Machine.FeatureKey] = item.Feature.Select(ConvertToInternalModel).ToArray();
+            {
+                machine[Models.Internal.Machine.FeatureKey] = item.Feature
+                    .Where(f => f != null)
+                    .Select(ConvertToInternalModel)
+                    .ToArray();
+            }
 
             if (item.Device != null && item.Device.Any())
-                machine[Models.Internal.Machine.DeviceKey] = item.Device.Select(ConvertToInternalModel).ToArray();
+            {
+                machine[Models.Internal.Machine.DeviceKey] = item.Device
+                    .Where(d => d != null)
+                    .Select(ConvertToInternalModel)
+                    .ToArray();
+            }
 
             if (item.Slot != null && item.Slot.Any())
-                machine[Models.Internal.Machine.SlotKey] = item.Slot.Select(ConvertToInternalModel).ToArray();
+            {
+                machine[Models.Internal.Machine.SlotKey] = item.Slot
+                    .Where(s => s != null)
+                    .Select(ConvertToInternalModel)
+                    .ToArray();
+            }
 
             if (item.SoftwareList != null && item.SoftwareList.Any())
-                machine[Models.Internal.Machine.SoftwareListKey] = item.SoftwareList.Select(ConvertToInternalModel).ToArray();
+            {
+                machine[Models.Internal.Machine.SoftwareListKey] = item.SoftwareList
+                    .Where(s => s != null)
+                    .Select(ConvertToInternalModel)
+                    .ToArray();
+            }
 
             if (item.RamOption != null && item.RamOption.Any())
-                machine[Models.Internal.Machine.RamOptionKey] = item.RamOption.Select(ConvertToInternalModel).ToArray();
+            {
+                machine[Models.Internal.Machine.RamOptionKey] = item.RamOption
+                    .Where(r => r != null)
+                    .Select(ConvertToInternalModel)
+                    .ToArray();
+            }
 
             return machine;
         }
@@ -243,10 +344,20 @@ namespace SabreTools.Serialization
                 configuration[Models.Internal.Configuration.ConditionKey] = ConvertToInternalModel(item.Condition);
 
             if (item.ConfLocation != null && item.ConfLocation.Any())
-                configuration[Models.Internal.Configuration.ConfLocationKey] = item.ConfLocation.Select(ConvertToInternalModel).ToArray();
+            {
+                configuration[Models.Internal.Configuration.ConfLocationKey] = item.ConfLocation
+                    .Where(c => c != null)
+                    .Select(ConvertToInternalModel)
+                    .ToArray();
+            }
 
             if (item.ConfSetting != null && item.ConfSetting.Any())
-                configuration[Models.Internal.Configuration.ConfSettingKey] = item.ConfSetting.Select(ConvertToInternalModel).ToArray();
+            {
+                configuration[Models.Internal.Configuration.ConfSettingKey] = item.ConfSetting
+                    .Where(c => c != null)
+                    .Select(ConvertToInternalModel)
+                    .ToArray();
+            }
 
             return configuration;
         }
@@ -324,7 +435,12 @@ namespace SabreTools.Serialization
                 device[Models.Internal.Device.InstanceKey] = ConvertToInternalModel(item.Instance);
 
             if (item.Extension != null && item.Extension.Any())
-                device[Models.Internal.Device.ExtensionKey] = item.Extension.Select(ConvertToInternalModel).ToArray();
+            {
+                device[Models.Internal.Device.ExtensionKey] = item.Extension
+                    .Where(e => e != null)
+                    .Select(ConvertToInternalModel)
+                    .ToArray();
+            }
 
             return device;
         }
@@ -371,10 +487,20 @@ namespace SabreTools.Serialization
                 dipSwitch[Models.Internal.DipSwitch.ConditionKey] = ConvertToInternalModel(item.Condition);
 
             if (item.DipLocation != null && item.DipLocation.Any())
-                dipSwitch[Models.Internal.DipSwitch.DipLocationKey] = item.DipLocation.Select(ConvertToInternalModel).ToArray();
+            {
+                dipSwitch[Models.Internal.DipSwitch.DipLocationKey] = item.DipLocation
+                    .Where(d => d != null)
+                    .Select(ConvertToInternalModel)
+                    .ToArray();
+            }
 
             if (item.DipValue != null && item.DipValue.Any())
-                dipSwitch[Models.Internal.DipSwitch.DipValueKey] = item.DipValue.Select(ConvertToInternalModel).ToArray();
+            {
+                dipSwitch[Models.Internal.DipSwitch.DipValueKey] = item.DipValue
+                    .Where(d => d != null)
+                    .Select(ConvertToInternalModel)
+                    .ToArray();
+            }
 
             return dipSwitch;
         }
@@ -506,7 +632,12 @@ namespace SabreTools.Serialization
             };
 
             if (item.Control != null && item.Control.Any())
-                input[Models.Internal.Input.ControlKey] = item.Control.Select(ConvertToInternalModel).ToArray();
+            {
+                input[Models.Internal.Input.ControlKey] = item.Control
+                    .Where(c => c != null)
+                    .Select(ConvertToInternalModel)
+                    .ToArray();
+            }
 
             return input;
         }
@@ -535,7 +666,12 @@ namespace SabreTools.Serialization
             };
 
             if (item.Analog != null && item.Analog.Any())
-                port[Models.Internal.Port.AnalogKey] = item.Analog.Select(ConvertToInternalModel).ToArray();
+            {
+                port[Models.Internal.Port.AnalogKey] = item.Analog
+                    .Where(a => a != null)
+                    .Select(ConvertToInternalModel)
+                    .ToArray();
+            }
 
             return port;
         }
@@ -599,7 +735,12 @@ namespace SabreTools.Serialization
             };
 
             if (item.SlotOption != null && item.SlotOption.Any())
-                slot[Models.Internal.Slot.SlotOptionKey] = item.SlotOption.Select(ConvertToInternalModel).ToArray();
+            {
+                slot[Models.Internal.Slot.SlotOptionKey] = item.SlotOption
+                    .Where(s => s != null)
+                    .Select(ConvertToInternalModel)
+                    .ToArray();
+            }
 
             return slot;
         }

SabreTools.Serialization/Logiqx.Deserializer.cs

@@ -29,10 +29,15 @@ namespace SabreTools.Serialization
             if (header != null)
                 datafile.Header = ConvertHeaderFromInternalModel(header);
 
-            // TODO: Handle Dir items
+            // TODO: Handle Dir items - Currently need to be generated from the machines
             var machines = item.Read<Models.Internal.Machine[]>(Models.Internal.MetadataFile.MachineKey);
             if (machines != null && machines.Any())
-                datafile.Game = machines.Select(machine => ConvertMachineFromInternalModel(machine, game)).ToArray();
+            {
+                datafile.Game = machines
+                    .Where(m => m != null)
+                    .Select(machine => ConvertMachineFromInternalModel(machine, game))
+                    .ToArray();
+            }
 
             return datafile;
         }
@@ -102,11 +107,8 @@ namespace SabreTools.Serialization
         /// <summary>
         /// Convert from <cref="Models.Internal.Machine"/> to <cref="Models.Logiqx.GameBase"/>
         /// </summary>
-        private static GameBase? ConvertMachineFromInternalModel(Models.Internal.Machine? item, bool game = false)
+        private static GameBase ConvertMachineFromInternalModel(Models.Internal.Machine item, bool game = false)
         {
-            if (item == null)
-                return null;
-
             GameBase gameBase = game ? new Game() : new Machine();
 
             gameBase.Name = item.ReadString(Models.Internal.Machine.NameKey);
@@ -130,37 +132,93 @@ namespace SabreTools.Serialization
             gameBase.Category = item.ReadStringArray(Models.Internal.Machine.CategoryKey);
 
             var trurip = item.Read<Trurip>(Models.Internal.Machine.TruripKey);
-            gameBase.Trurip = trurip;
+            if (trurip != null)
+                gameBase.Trurip = trurip;
 
             var releases = item.Read<Models.Internal.Release[]>(Models.Internal.Machine.ReleaseKey);
-            gameBase.Release = releases?.Select(ConvertFromInternalModel)?.ToArray();
+            if (releases != null && releases.Any())
+            {
+                gameBase.Release = releases
+                    .Where(r => r != null)
+                    .Select(ConvertFromInternalModel)
+                    .ToArray();
+            }
 
             var biosSets = item.Read<Models.Internal.BiosSet[]>(Models.Internal.Machine.BiosSetKey);
-            gameBase.BiosSet = biosSets?.Select(ConvertFromInternalModel)?.ToArray();
+            if (biosSets != null && biosSets.Any())
+            {
+                gameBase.BiosSet = biosSets
+                    .Where(b => b != null)
+                    .Select(ConvertFromInternalModel)
+                    .ToArray();
+            }
 
             var roms = item.Read<Models.Internal.Rom[]>(Models.Internal.Machine.RomKey);
-            gameBase.Rom = roms?.Select(ConvertFromInternalModel)?.ToArray();
+            if (roms != null && roms.Any())
+            {
+                gameBase.Rom = roms
+                    .Where(r => r != null)
+                    .Select(ConvertFromInternalModel)
+                    .ToArray();
+            }
 
             var disks = item.Read<Models.Internal.Disk[]>(Models.Internal.Machine.DiskKey);
-            gameBase.Disk = disks?.Select(ConvertFromInternalModel)?.ToArray();
+            if (disks != null && disks.Any())
+            {
+                gameBase.Disk = disks
+                    .Where(d => d != null)
+                    .Select(ConvertFromInternalModel)
+                    .ToArray();
+            }
 
             var medias = item.Read<Models.Internal.Media[]>(Models.Internal.Machine.MediaKey);
-            gameBase.Media = medias?.Select(ConvertFromInternalModel)?.ToArray();
+            if (medias != null && medias.Any())
+            {
+                gameBase.Media = medias
+                    .Where(m => m != null)
+                    .Select(ConvertFromInternalModel)
+                    .ToArray();
+            }
 
             var deviceRefs = item.Read<Models.Internal.DeviceRef[]>(Models.Internal.Machine.DeviceRefKey);
-            gameBase.DeviceRef = deviceRefs?.Select(ConvertFromInternalModel)?.ToArray();
+            if (deviceRefs != null && deviceRefs.Any())
+            {
+                gameBase.DeviceRef = deviceRefs
+                    .Where(m => m != null)
+                    .Select(ConvertFromInternalModel)
+                    .ToArray();
+            }
 
             var samples = item.Read<Models.Internal.Sample[]>(Models.Internal.Machine.SampleKey);
-            gameBase.Sample = samples?.Select(ConvertFromInternalModel)?.ToArray();
+            if (samples != null && samples.Any())
+            {
+                gameBase.Sample = samples
+                    .Where(m => m != null)
+                    .Select(ConvertFromInternalModel)
+                    .ToArray();
+            }
 
             var archives = item.Read<Models.Internal.Archive[]>(Models.Internal.Machine.ArchiveKey);
-            gameBase.Archive = archives?.Select(ConvertFromInternalModel)?.ToArray();
+            if (archives != null && archives.Any())
+            {
+                gameBase.Archive = archives
+                    .Where(m => m != null)
+                    .Select(ConvertFromInternalModel)
+                    .ToArray();
+            }
 
-            var drivers = item.Read<Models.Internal.Driver[]>(Models.Internal.Machine.DriverKey);
+            var driver = item.Read<Models.Internal.Driver>(Models.Internal.Machine.DriverKey);
-            gameBase.Driver = drivers?.Select(ConvertFromInternalModel)?.ToArray();
+            if (driver != null)
+                gameBase.Driver = ConvertFromInternalModel(driver);
 
             var softwareLists = item.Read<Models.Internal.SoftwareList[]>(Models.Internal.Machine.SoftwareListKey);
-            gameBase.SoftwareList = softwareLists?.Select(ConvertFromInternalModel)?.ToArray();
+            if (softwareLists != null && softwareLists.Any())
+            {
+                gameBase.SoftwareList = softwareLists
+                    .Where(m => m != null)
+                    .Select(ConvertFromInternalModel)
+                    .ToArray();
+            }
 
             return gameBase;
         }
@@ -168,11 +226,8 @@ namespace SabreTools.Serialization
         /// <summary>
         /// Convert from <cref="Models.Internal.Archive"/> to <cref="Models.Logiqx.Archive"/>
         /// </summary>
-        private static Archive? ConvertFromInternalModel(Models.Internal.Archive? item)
+        private static Archive ConvertFromInternalModel(Models.Internal.Archive item)
         {
-            if (item == null)
-                return null;
-
             var archive = new Archive
             {
                 Name = item.ReadString(Models.Internal.Archive.NameKey),
@@ -183,11 +238,8 @@ namespace SabreTools.Serialization
         /// <summary>
         /// Convert from <cref="Models.Internal.BiosSet"/> to <cref="Models.Logiqx.BiosSet"/>
         /// </summary>
-        private static BiosSet? ConvertFromInternalModel(Models.Internal.BiosSet? item)
+        private static BiosSet ConvertFromInternalModel(Models.Internal.BiosSet item)
         {
-            if (item == null)
-                return null;
-
             var biosset = new BiosSet
             {
                 Name = item.ReadString(Models.Internal.BiosSet.NameKey),
@@ -200,11 +252,8 @@ namespace SabreTools.Serialization
         /// <summary>
         /// Convert from <cref="Models.Internal.DeviceRef"/> to <cref="Models.Logiqx.DeviceRef"/>
         /// </summary>
-        private static DeviceRef? ConvertFromInternalModel(Models.Internal.DeviceRef? item)
+        private static DeviceRef ConvertFromInternalModel(Models.Internal.DeviceRef item)
         {
-            if (item == null)
-                return null;
-
             var deviceRef = new DeviceRef
             {
                 Name = item.ReadString(Models.Internal.DipSwitch.NameKey),
@@ -215,11 +264,8 @@ namespace SabreTools.Serialization
         /// <summary>
         /// Convert from <cref="Models.Internal.Disk"/> to <cref="Models.Logiqx.Disk"/>
         /// </summary>
-        private static Disk? ConvertFromInternalModel(Models.Internal.Disk? item)
+        private static Disk ConvertFromInternalModel(Models.Internal.Disk item)
         {
-            if (item == null)
-                return null;
-
             var disk = new Disk
             {
                 Name = item.ReadString(Models.Internal.Disk.NameKey),
@@ -235,11 +281,8 @@ namespace SabreTools.Serialization
         /// <summary>
         /// Convert from <cref="Models.Internal.Driver"/> to <cref="Models.Logiqx.Driver"/>
         /// </summary>
-        private static Driver? ConvertFromInternalModel(Models.Internal.Driver? item)
+        private static Driver ConvertFromInternalModel(Models.Internal.Driver item)
         {
-            if (item == null)
-                return null;
-
             var driver = new Driver
             {
                 Status = item.ReadString(Models.Internal.Driver.StatusKey),
@@ -257,11 +300,8 @@ namespace SabreTools.Serialization
         /// <summary>
         /// Convert from <cref="Models.Internal.Media"/> to <cref="Models.Logiqx.Media"/>
         /// </summary>
-        private static Media? ConvertFromInternalModel(Models.Internal.Media? item)
+        private static Media ConvertFromInternalModel(Models.Internal.Media item)
         {
-            if (item == null)
-                return null;
-
             var media = new Media
             {
                 Name = item.ReadString(Models.Internal.Media.NameKey),
@@ -276,11 +316,8 @@ namespace SabreTools.Serialization
         /// <summary>
         /// Convert from <cref="Models.Internal.Release"/> to <cref="Models.Logiqx.Release"/>
         /// </summary>
-        private static Release? ConvertFromInternalModel(Models.Internal.Release? item)
+        private static Release ConvertFromInternalModel(Models.Internal.Release item)
         {
-            if (item == null)
-                return null;
-
             var release = new Release
             {
                 Name = item.ReadString(Models.Internal.Release.NameKey),
@@ -295,7 +332,7 @@ namespace SabreTools.Serialization
         /// <summary>
         /// Convert from <cref="Models.Internal.Rom"/> to <cref="Models.Logiqx.Rom"/>
         /// </summary>
-        private static Rom? ConvertFromInternalModel(Models.Internal.Rom? item)
+        private static Rom ConvertFromInternalModel(Models.Internal.Rom item)
         {
             if (item == null)
                 return null;
@@ -327,11 +364,8 @@ namespace SabreTools.Serialization
         /// <summary>
         /// Convert from <cref="Models.Internal.Sample"/> to <cref="Models.Logiqx.Sample"/>
         /// </summary>
-        private static Sample? ConvertFromInternalModel(Models.Internal.Sample? item)
+        private static Sample ConvertFromInternalModel(Models.Internal.Sample item)
         {
-            if (item == null)
-                return null;
-
             var sample = new Sample
             {
                 Name = item.ReadString(Models.Internal.Sample.NameKey),
@@ -342,11 +376,8 @@ namespace SabreTools.Serialization
         /// <summary>
         /// Convert from <cref="Models.Internal.SoftwareList"/> to <cref="Models.Logiqx.SoftwareList"/>
         /// </summary>
-        private static SoftwareList? ConvertFromInternalModel(Models.Internal.SoftwareList? item)
+        private static SoftwareList ConvertFromInternalModel(Models.Internal.SoftwareList item)
         {
-            if (item == null)
-                return null;
-
             var softwareList = new SoftwareList
             {
                 Tag = item.ReadString(Models.Internal.SoftwareList.TagKey),

SabreTools.Serialization/Logiqx.Serializer.cs

@@ -1,3 +1,5 @@
+using System;
+using System.Collections.Generic;
 using System.IO;
 using System.Linq;
 using SabreTools.Models.Logiqx;
@@ -22,16 +24,34 @@ namespace SabreTools.Serialization
         /// <summary>
         /// Convert from <cref="Models.Logiqx.Datafile"/> to <cref="Models.Internal.MetadataFile"/>
         /// </summary>
-        public static Models.Internal.MetadataFile ConvertToInternalModel(Datafile item)
+        public static Models.Internal.MetadataFile? ConvertToInternalModel(Datafile? item)
         {
+            if (item == null)
+                return null;
+
             var metadataFile = new Models.Internal.MetadataFile
             {
                 [Models.Internal.MetadataFile.HeaderKey] = ConvertHeaderToInternalModel(item),
             };
 
-            // TODO: Handle Dir items
+            var machines = new List<Models.Internal.Machine>();
-            if (item?.Game != null && item.Game.Any())
+
-                metadataFile[Models.Internal.MetadataFile.MachineKey] = item.Game.Select(ConvertMachineToInternalModel).ToArray();
+            if (item.Game != null && item.Game.Any())
+            {
+               machines.AddRange(item.Game
+                    .Where(g => g != null)
+                    .Select(ConvertMachineToInternalModel));
+            }
+
+            if (item.Dir != null && item.Dir.Any())
+            {
+                machines.AddRange(item.Dir
+                    .Where(d => d != null)
+                    .SelectMany(ConvertDirToInternalModel));
+            }
+
+            if (machines.Any())
+                metadataFile[Models.Internal.MetadataFile.MachineKey] = machines.ToArray();
 
             return metadataFile;
         }
@@ -41,7 +61,7 @@ namespace SabreTools.Serialization
         /// </summary>
         private static Models.Internal.Header ConvertHeaderToInternalModel(Datafile item)
         {
-            var header = ConvertHeaderToInternalModel(item.Header);
+            var header = item.Header != null ? ConvertHeaderToInternalModel(item.Header) : new Models.Internal.Header();
 
             header[Models.Internal.Header.BuildKey] = item.Build;
             header[Models.Internal.Header.DebugKey] = item.Debug;
@@ -94,6 +114,25 @@ namespace SabreTools.Serialization
             return header;
         }
 
+        /// <summary>
+        /// Convert from <cref="Models.Logiqx.Dir"/> to an array of <cref="Models.Internal.Machine"/>
+        /// </summary>
+        private static Models.Internal.Machine[] ConvertDirToInternalModel(Dir item)
+        {
+            if (item.Game == null || !item.Game.Any())
+                return Array.Empty<Models.Internal.Machine>();
+
+            return item.Game
+                .Where(g => g != null)
+                .Select(game =>
+                {
+                    var machine = ConvertMachineToInternalModel(game);
+                    machine[Models.Internal.Machine.DirNameKey] = item.Name;
+                    return machine;
+                })
+                .ToArray();
+        }
+
         /// <summary>
         /// Convert from <cref="Models.Logiqx.GameBase"/> to <cref="Models.Internal.Machine"/>
         /// </summary>
@@ -147,8 +186,8 @@ namespace SabreTools.Serialization
             if (item.Archive != null && item.Archive.Any())
                 machine[Models.Internal.Machine.ArchiveKey] = item.Archive.Select(ConvertToInternalModel).ToArray();
 
-            if (item.Driver != null && item.Driver.Any())
+            if (item.Driver != null)
-                machine[Models.Internal.Machine.DriverKey] = item.Driver.Select(ConvertToInternalModel).ToArray();
+                machine[Models.Internal.Machine.DriverKey] = ConvertToInternalModel(item.Driver);
 
             if (item.SoftwareList != null && item.SoftwareList.Any())
                 machine[Models.Internal.Machine.SoftwareListKey] = item.SoftwareList.Select(ConvertToInternalModel).ToArray();

SabreTools.Serialization/OfflineList.Deserializer.cs

@@ -23,7 +23,15 @@ namespace SabreTools.Serialization
 
             var machines = item.Read<Models.Internal.Machine[]>(Models.Internal.MetadataFile.MachineKey);
             if (machines != null && machines.Any())
-                dat.Games = new Games { Game = machines.Select(ConvertMachineFromInternalModel).ToArray() };
+            {
+                dat.Games = new Games
+                {
+                    Game = machines
+                        .Where(m => m != null)
+                        .Select(ConvertMachineFromInternalModel)
+                        .ToArray()
+                };
+            }
 
             return dat;
         }
@@ -31,11 +39,8 @@ namespace SabreTools.Serialization
         /// <summary>
         /// Convert from <cref="Models.Internal.Header"/> to <cref="Models.OfflineList.Dat"/>
         /// </summary>
-        private static Dat? ConvertHeaderFromInternalModel(Models.Internal.Header? item)
+        private static Dat ConvertHeaderFromInternalModel(Models.Internal.Header item)
         {
-            if (item == null)
-                return null;
-
             var dat = new Dat
             {
                 NoNamespaceSchemaLocation = item.ReadString(Models.Internal.Header.SchemaLocationKey),
@@ -83,11 +88,8 @@ namespace SabreTools.Serialization
         /// <summary>
         /// Convert from <cref="Models.Internal.Machine"/> to <cref="Models.OfflineList.Game"/>
         /// </summary>
-        private static Game? ConvertMachineFromInternalModel(Models.Internal.Machine? item)
+        private static Game ConvertMachineFromInternalModel(Models.Internal.Machine item)
         {
-            if (item == null)
-                return null;
-
             var game = new Game
             {
                 ImageNumber = item.ReadString(Models.Internal.Machine.ImageNumberKey),
@@ -105,11 +107,19 @@ namespace SabreTools.Serialization
             };
 
             var roms = item.Read<Models.Internal.Rom[]>(Models.Internal.Machine.RomKey);
-            game.RomSize = roms?
+            if (roms != null && roms.Any())
-                .Select(rom => rom.ReadString(Models.Internal.Rom.SizeKey))?
+            {
-                .FirstOrDefault(s => s != null);
+                game.RomSize = roms
-            var romCRCs = roms?.Select(ConvertFromInternalModel).ToArray();
+                    .Select(rom => rom.ReadString(Models.Internal.Rom.SizeKey))
-            game.Files = new Files { RomCRC = romCRCs };
+                    .FirstOrDefault(s => s != null);
+
+                var romCRCs = roms
+                    .Where(r => r != null)
+                    .Select(ConvertFromInternalModel)
+                    .ToArray();
+
+                game.Files = new Files { RomCRC = romCRCs };
+            }
 
             return game;
         }
@@ -117,11 +127,8 @@ namespace SabreTools.Serialization
         /// <summary>
         /// Convert from <cref="Models.Internal.Rom"/> to <cref="Models.OfflineList.FileRomCRC"/>
         /// </summary>
-        private static FileRomCRC? ConvertFromInternalModel(Models.Internal.Rom? item)
+        private static FileRomCRC ConvertFromInternalModel(Models.Internal.Rom item)
         {
-            if (item == null)
-                return null;
-
             var fileRomCRC = new FileRomCRC
             {
                 Extension = item.ReadString(Models.Internal.Rom.ExtensionKey),

SabreTools.Serialization/OfflineList.Serializer.cs

@@ -13,15 +13,23 @@ namespace SabreTools.Serialization
         /// <summary>
         /// Convert from <cref="Models.OfflineList.Dat"/> to <cref="Models.Internal.MetadataFile"/>
         /// </summary>
-        public static Models.Internal.MetadataFile ConvertToInternalModel(Dat item)
+        public static Models.Internal.MetadataFile? ConvertToInternalModel(Dat? item)
         {
+            if (item == null)
+                return null;
+
             var metadataFile = new Models.Internal.MetadataFile
             {
                 [Models.Internal.MetadataFile.HeaderKey] = ConvertHeaderToInternalModel(item),
             };
 
             if (item?.Games?.Game != null && item.Games.Game.Any())
-                metadataFile[Models.Internal.MetadataFile.MachineKey] = item.Games.Game.Select(ConvertMachineToInternalModel).ToArray();
+            {
+                metadataFile[Models.Internal.MetadataFile.MachineKey] = item.Games.Game
+                    .Where(g => g != null)
+                    .Select(ConvertMachineToInternalModel)
+                    .ToArray();
+            }
 
             return metadataFile;
         }
@@ -82,12 +90,15 @@ namespace SabreTools.Serialization
 
             if (item.Files?.RomCRC != null && item.Files.RomCRC.Any())
             {
-                machine[Models.Internal.Machine.RomKey] = item.Files.RomCRC.Select(romCRC =>
+                machine[Models.Internal.Machine.RomKey] = item.Files.RomCRC
-                {
+                    .Where(r => r != null)
-                    var rom = ConvertToInternalModel(romCRC);
+                    .Select(romCRC =>
-                    rom[Models.Internal.Rom.SizeKey] = item.RomSize;
+                    {
-                    return rom;
+                        var rom = ConvertToInternalModel(romCRC);
-                }).ToArray();
+                        rom[Models.Internal.Rom.SizeKey] = item.RomSize;
+                        return rom;
+                    })
+                    .ToArray();
             }
 
             return machine;

SabreTools.Serialization/OpenMSX.Deserializer.cs

@@ -23,7 +23,12 @@ namespace SabreTools.Serialization
 
             var machines = item.Read<Models.Internal.Machine[]>(Models.Internal.MetadataFile.MachineKey);
             if (machines != null && machines.Any())
-                softwareDb.Software = machines.Select(ConvertMachineFromInternalModel).ToArray();
+            {
+                softwareDb.Software = machines
+                    .Where(m => m != null)
+                    .Select(ConvertMachineFromInternalModel)
+                    .ToArray();
+            }
             
             return softwareDb;
         }
@@ -31,11 +36,8 @@ namespace SabreTools.Serialization
         /// <summary>
         /// Convert from <cref="Models.Internal.Header"/> to <cref="Models.OpenMSX.SoftwareDb"/>
         /// </summary>
-        private static SoftwareDb? ConvertHeaderFromInternalModel(Models.Internal.Header? item)
+        private static SoftwareDb ConvertHeaderFromInternalModel(Models.Internal.Header item)
         {
-            if (item == null)
-                return null;
-
             var softwareDb = new SoftwareDb
             {
                 Timestamp = item.ReadString(Models.Internal.Header.TimestampKey),
@@ -46,11 +48,8 @@ namespace SabreTools.Serialization
         /// <summary>
         /// Convert from <cref="Models.Internal.Machine"/> to <cref="Models.OpenMSX.Software"/>
         /// </summary>
-        private static Software? ConvertMachineFromInternalModel(Models.Internal.Machine? item)
+        private static Software ConvertMachineFromInternalModel(Models.Internal.Machine item)
         {
-            if (item == null)
-                return null;
-            
             var game = new Software
             {
                 Title = item.ReadString(Models.Internal.Machine.NameKey),
@@ -62,7 +61,13 @@ namespace SabreTools.Serialization
             };
 
             var dumps = item.Read<Models.Internal.Dump[]>(Models.Internal.Machine.DumpKey);
-            game.Dump = dumps?.Select(ConvertFromInternalModel)?.ToArray();
+            if (dumps != null && dumps.Any())
+            {
+                game.Dump = dumps
+                    .Where(d => d != null)
+                    .Select(ConvertFromInternalModel)
+                    .ToArray();
+            }
 
             return game;
         }
@@ -70,24 +75,25 @@ namespace SabreTools.Serialization
         /// <summary>
         /// Convert from <cref="Models.Internal.Dump"/> to <cref="Models.OpenMSX.Dump"/>
         /// </summary>
-        private static Dump? ConvertFromInternalModel(Models.Internal.Dump? item)
+        private static Dump ConvertFromInternalModel(Models.Internal.Dump item)
         {
-            if (item == null)
-                return null;
-            
             var dump = new Dump();
 
             var original = item.Read<Models.Internal.Original>(Models.Internal.Dump.OriginalKey);
-            dump.Original = ConvertFromInternalModel(original);
+            if (original != null)
+                dump.Original = ConvertFromInternalModel(original);
 
             var rom = item.Read<Models.Internal.Rom>(Models.Internal.Dump.RomKey);
-            dump.Rom = ConvertRomFromInternalModel(rom);
+            if (rom != null)
+                dump.Rom = ConvertRomFromInternalModel(rom);
 
             var megaRom = item.Read<Models.Internal.Rom>(Models.Internal.Dump.MegaRomKey);
-            dump.Rom = ConvertMegaRomFromInternalModel(megaRom);
+            if (megaRom != null)
+                dump.Rom = ConvertMegaRomFromInternalModel(megaRom);
 
             var sccPlusCart = item.Read<Models.Internal.Rom>(Models.Internal.Dump.SCCPlusCartKey);
-            dump.Rom = ConvertSCCPlusCartFromInternalModel(sccPlusCart);
+            if (sccPlusCart != null)
+                dump.Rom = ConvertSCCPlusCartFromInternalModel(sccPlusCart);
 
             return dump;
         }
@@ -95,11 +101,8 @@ namespace SabreTools.Serialization
         /// <summary>
         /// Convert from <cref="Models.Internal.Rom"/> to <cref="Models.OpenMSX.MegaRom"/>
         /// </summary>
-        private static MegaRom? ConvertMegaRomFromInternalModel(Models.Internal.Rom? item)
+        private static MegaRom ConvertMegaRomFromInternalModel(Models.Internal.Rom item)
         {
-            if (item == null)
-                return null;
-            
             var megaRom = new MegaRom
             {
                 Start = item.ReadString(Models.Internal.Rom.StartKey),
@@ -113,11 +116,8 @@ namespace SabreTools.Serialization
         /// <summary>
         /// Convert from <cref="Models.Internal.Original"/> to <cref="Models.OpenMSX.Original"/>
         /// </summary>
-        private static Original? ConvertFromInternalModel(Models.Internal.Original? item)
+        private static Original ConvertFromInternalModel(Models.Internal.Original item)
         {
-            if (item == null)
-                return null;
-            
             var original = new Original
             {
                 Value = item.ReadString(Models.Internal.Original.ValueKey),
@@ -129,11 +129,8 @@ namespace SabreTools.Serialization
         /// <summary>
         /// Convert from <cref="Models.Internal.Rom"/> to <cref="Models.OpenMSX.Rom"/>
         /// </summary>
-        private static Rom? ConvertRomFromInternalModel(Models.Internal.Rom? item)
+        private static Rom ConvertRomFromInternalModel(Models.Internal.Rom item)
         {
-            if (item == null)
-                return null;
-            
             var rom = new Rom
             {
                 Start = item.ReadString(Models.Internal.Rom.StartKey),
@@ -147,11 +144,8 @@ namespace SabreTools.Serialization
         /// <summary>
         /// Convert from <cref="Models.Internal.Rom"/> to <cref="Models.OpenMSX.SCCPlusCart"/>
         /// </summary>
-        private static SCCPlusCart? ConvertSCCPlusCartFromInternalModel(Models.Internal.Rom? item)
+        private static SCCPlusCart ConvertSCCPlusCartFromInternalModel(Models.Internal.Rom item)
         {
-            if (item == null)
-                return null;
-            
             var sccPlusCart = new SCCPlusCart
             {
                 Start = item.ReadString(Models.Internal.Rom.StartKey),

SabreTools.Serialization/OpenMSX.Serializer.cs

@@ -22,15 +22,23 @@ namespace SabreTools.Serialization
         /// <summary>
         /// Convert from <cref="Models.OpenMSX.SoftwareDb"/> to <cref="Models.Internal.MetadataFile"/>
         /// </summary>
-        public static Models.Internal.MetadataFile ConvertToInternalModel(SoftwareDb item)
+        public static Models.Internal.MetadataFile? ConvertToInternalModel(SoftwareDb? item)
         {
+            if (item == null)
+                return null;
+
             var metadataFile = new Models.Internal.MetadataFile
             {
                 [Models.Internal.MetadataFile.HeaderKey] = ConvertHeaderToInternalModel(item),
             };
 
             if (item?.Software != null && item.Software.Any())
-                metadataFile[Models.Internal.MetadataFile.MachineKey] = item.Software.Select(ConvertMachineToInternalModel).ToArray();
+            {
+                metadataFile[Models.Internal.MetadataFile.MachineKey] = item.Software
+                    .Where(s => s != null)
+                    .Select(ConvertMachineToInternalModel)
+                    .ToArray();
+            }
 
             return metadataFile;
         }
@@ -63,7 +71,12 @@ namespace SabreTools.Serialization
             };
 
             if (item.Dump != null && item.Dump.Any())
-                machine[Models.Internal.Machine.DumpKey] = item.Dump.Select(ConvertToInternalModel).ToArray();
+            {
+                machine[Models.Internal.Machine.DumpKey] = item.Dump
+                    .Where(d => d != null)
+                    .Select(ConvertToInternalModel)
+                    .ToArray();
+            }
 
             return machine;
         }
@@ -78,19 +91,22 @@ namespace SabreTools.Serialization
             if (item.Original != null)
                 dump[Models.Internal.Dump.OriginalKey] = ConvertToInternalModel(item.Original);
 
-            switch (item.Rom)
+            if (item.Rom != null)
             {
-                case Rom rom:
+                switch (item.Rom)
-                    dump[Models.Internal.Dump.RomKey] = ConvertToInternalModel(rom);
+                {
-                    break;
+                    case Rom rom:
+                        dump[Models.Internal.Dump.RomKey] = ConvertToInternalModel(rom);
+                        break;
 
-                case MegaRom megaRom:
+                    case MegaRom megaRom:
-                    dump[Models.Internal.Dump.MegaRomKey] = ConvertToInternalModel(megaRom);
+                        dump[Models.Internal.Dump.MegaRomKey] = ConvertToInternalModel(megaRom);
-                    break;
+                        break;
 
-                case SCCPlusCart sccPlusCart:
+                    case SCCPlusCart sccPlusCart:
-                    dump[Models.Internal.Dump.SCCPlusCartKey] = ConvertToInternalModel(sccPlusCart);
+                        dump[Models.Internal.Dump.SCCPlusCartKey] = ConvertToInternalModel(sccPlusCart);
-                    break;
+                        break;
+                }
             }
 
             return dump;

SabreTools.Serialization/RomCenter.Deserializer.cs

@@ -1,3 +1,4 @@
+using System;
 using System.Collections.Generic;
 using System.IO;
 using System.Linq;
@@ -236,7 +237,15 @@ namespace SabreTools.Serialization
 
             var machines = item.Read<Models.Internal.Machine[]>(Models.Internal.MetadataFile.MachineKey);
             if (machines != null && machines.Any())
-                metadataFile.Games = new Games { Rom = machines.SelectMany(ConvertMachineFromInternalModel).ToArray() };
+            {
+                metadataFile.Games = new Games
+                {
+                    Rom = machines
+                        .Where(m => m != null)
+                        .SelectMany(ConvertMachineFromInternalModel)
+                        .ToArray()
+                };
+            }
 
             return metadataFile;
         }
@@ -244,11 +253,8 @@ namespace SabreTools.Serialization
         /// <summary>
         /// Convert from <cref="Models.Internal.Header"/> to <cref="Models.RomCenter.MetadataFile"/>
         /// </summary>
-        private static MetadataFile? ConvertHeaderFromInternalModel(Models.Internal.Header? item)
+        private static MetadataFile ConvertHeaderFromInternalModel(Models.Internal.Header item)
         {
-            if (item == null)
-                return null;
-
             var metadataFile = new MetadataFile();
 
             if (item.ContainsKey(Models.Internal.Header.AuthorKey)
@@ -300,23 +306,23 @@ namespace SabreTools.Serialization
         /// <summary>
         /// Convert from <cref="Models.Internal.Machine"/> to an array of <cref="Models.RomCenter.Rom"/>
         /// </summary>
-        private static Rom?[]? ConvertMachineFromInternalModel(Models.Internal.Machine? item)
+        private static Rom[] ConvertMachineFromInternalModel(Models.Internal.Machine item)
         {
-            if (item == null)
-                return null;
-
             var roms = item.Read<Models.Internal.Rom[]>(Models.Internal.Machine.RomKey);
-            return roms?.Select(rom => ConvertFromInternalModel(rom, item))?.ToArray();
+            if (roms == null)
+                return Array.Empty<Rom>();
+
+            return roms
+                .Where(r => r != null)
+                .Select(rom => ConvertFromInternalModel(rom, item))
+                .ToArray();
         }
 
         /// <summary>
         /// Convert from <cref="Models.Internal.Rom"/> to <cref="Models.RomCenter.Rom"/>
         /// </summary>
-        private static Rom? ConvertFromInternalModel(Models.Internal.Rom? item, Models.Internal.Machine? parent)
+        private static Rom ConvertFromInternalModel(Models.Internal.Rom item, Models.Internal.Machine parent)
         {
-            if (item == null)
-                return null;
-
             var row = new Rom
             {
                 RomName = item.ReadString(Models.Internal.Rom.NameKey),
@@ -324,10 +330,10 @@ namespace SabreTools.Serialization
                 RomSize = item.ReadString(Models.Internal.Rom.SizeKey),
                 MergeName = item.ReadString(Models.Internal.Rom.MergeKey),
 
-                ParentName = parent?.ReadString(Models.Internal.Machine.RomOfKey),
+                ParentName = parent.ReadString(Models.Internal.Machine.RomOfKey),
-                //ParentDescription = parent?.ReadString(Models.Internal.Machine.ParentDescriptionKey), // This is unmappable
+                //ParentDescription = parent.ReadString(Models.Internal.Machine.ParentDescriptionKey), // This is unmappable
-                GameName = parent?.ReadString(Models.Internal.Machine.NameKey),
+                GameName = parent.ReadString(Models.Internal.Machine.NameKey),
-                GameDescription = parent?.ReadString(Models.Internal.Machine.DescriptionKey),
+                GameDescription = parent.ReadString(Models.Internal.Machine.DescriptionKey),
             };
             return row;
         }

SabreTools.Serialization/RomCenter.Serializer.cs

@@ -178,15 +178,22 @@ namespace SabreTools.Serialization
         /// <summary>
         /// Convert from <cref="Models.RomCenter.MetadataFile"/> to <cref="Models.Internal.MetadataFile"/>
         /// </summary>
-        public static Models.Internal.MetadataFile ConvertToInternalModel(MetadataFile item)
+        public static Models.Internal.MetadataFile? ConvertToInternalModel(MetadataFile? item)
         {
+            if (item == null)
+                return null;
+            
             var metadataFile = new Models.Internal.MetadataFile
             {
                 [Models.Internal.MetadataFile.HeaderKey] = ConvertHeaderToInternalModel(item),
             };
 
             if (item?.Games?.Rom != null && item.Games.Rom.Any())
-                metadataFile[Models.Internal.MetadataFile.MachineKey] = item.Games.Rom.Select(ConvertMachineToInternalModel).ToArray();
+            {
+                metadataFile[Models.Internal.MetadataFile.MachineKey] = item.Games.Rom
+                    .Where(r => r != null)
+                    .Select(ConvertMachineToInternalModel).ToArray();
+            }
 
             return metadataFile;
         }

SabreTools.Serialization/SeparatedValue.Deserializer.cs

@@ -135,7 +135,12 @@ namespace SabreTools.Serialization
 
             var machines = item.Read<Models.Internal.Machine[]>(Models.Internal.MetadataFile.MachineKey);
             if (machines != null && machines.Any())
-                metadataFile.Row = machines.SelectMany(ConvertMachineFromInternalModel).ToArray();
+            {
+                metadataFile.Row = machines
+                    .Where(m => m != null)
+                    .SelectMany(ConvertMachineFromInternalModel)
+                    .ToArray();
+            }
 
             return metadataFile;
         }
@@ -143,11 +148,8 @@ namespace SabreTools.Serialization
         /// <summary>
         /// Convert from <cref="Models.Internal.Header"/> to <cref="Models.SeparatedValue.MetadataFile"/>
         /// </summary>
-        private static MetadataFile? ConvertHeaderFromInternalModel(Models.Internal.Header? item)
+        private static MetadataFile ConvertHeaderFromInternalModel(Models.Internal.Header item)
         {
-            if (item == null)
-                return null;
-
             var metadataFile = new MetadataFile
             {
                 Header = item.ReadStringArray(Models.Internal.Header.HeaderKey),
@@ -158,24 +160,33 @@ namespace SabreTools.Serialization
         /// <summary>
         /// Convert from <cref="Models.Internal.Machine"/> to an array of <cref="Models.SeparatedValue.Row"/>
         /// </summary>
-        private static Row[]? ConvertMachineFromInternalModel(Models.Internal.Machine? item)
+        private static Row[] ConvertMachineFromInternalModel(Models.Internal.Machine item)
         {
-            if (item == null)
-                return null;
-
             var rowItems = new List<Row>();
 
+            var roms = item.Read<Models.Internal.Rom[]>(Models.Internal.Machine.RomKey);
+            if (roms != null && roms.Any())
+            {
+                rowItems.AddRange(roms
+                    .Where(r => r != null)
+                    .Select(rom => ConvertFromInternalModel(rom, item)));
+            }
+
             var disks = item.Read<Models.Internal.Disk[]>(Models.Internal.Machine.DiskKey);
-            if (disks != null)
+            if (disks != null && disks.Any())
-                rowItems.AddRange(disks.Select(disk => ConvertFromInternalModel(disk, item)));
+            {
+                rowItems.AddRange(disks
+                    .Where(d => d != null)
+                    .Select(disk => ConvertFromInternalModel(disk, item)));
+            }
 
             var media = item.Read<Models.Internal.Media[]>(Models.Internal.Machine.MediaKey);
-            if (media != null)
+            if (media != null && media.Any())
-                rowItems.AddRange(media.Select(medium => ConvertFromInternalModel(medium, item)));
+            {
-
+                rowItems.AddRange(media
-            var roms = item.Read<Models.Internal.Rom[]>(Models.Internal.Machine.RomKey);
+                    .Where(m => m != null)
-            if (roms != null)
+                    .Select(medium => ConvertFromInternalModel(medium, item)));
-                rowItems.AddRange(roms.Select(rom => ConvertFromInternalModel(rom, item)));
+            }
 
             return rowItems.ToArray();
         }
@@ -183,15 +194,12 @@ namespace SabreTools.Serialization
         /// <summary>
         /// Convert from <cref="Models.Internal.Disk"/> to <cref="Models.SeparatedValue.Row"/>
         /// </summary>
-        private static Row? ConvertFromInternalModel(Models.Internal.Disk? item, Models.Internal.Machine? parent)
+        private static Row ConvertFromInternalModel(Models.Internal.Disk item, Models.Internal.Machine parent)
         {
-            if (item == null)
-                return null;
-
             var row = new Row
             {
-                GameName = parent?.ReadString(Models.Internal.Machine.NameKey),
+                GameName = parent.ReadString(Models.Internal.Machine.NameKey),
-                Description = parent?.ReadString(Models.Internal.Machine.DescriptionKey),
+                Description = parent.ReadString(Models.Internal.Machine.DescriptionKey),
                 Type = "disk",
                 DiskName = item.ReadString(Models.Internal.Disk.NameKey),
                 MD5 = item.ReadString(Models.Internal.Disk.MD5Key),
@@ -204,15 +212,12 @@ namespace SabreTools.Serialization
         /// <summary>
         /// Convert from <cref="Models.Internal.Media"/> to <cref="Models.SeparatedValue.Row"/>
         /// </summary>
-        private static Row? ConvertFromInternalModel(Models.Internal.Media? item, Models.Internal.Machine? parent)
+        private static Row ConvertFromInternalModel(Models.Internal.Media item, Models.Internal.Machine parent)
         {
-            if (item == null)
-                return null;
-
             var row = new Row
             {
-                GameName = parent?.ReadString(Models.Internal.Machine.NameKey),
+                GameName = parent.ReadString(Models.Internal.Machine.NameKey),
-                Description = parent?.ReadString(Models.Internal.Machine.DescriptionKey),
+                Description = parent.ReadString(Models.Internal.Machine.DescriptionKey),
                 Type = "media",
                 DiskName = item.ReadString(Models.Internal.Media.NameKey),
                 MD5 = item.ReadString(Models.Internal.Media.MD5Key),
@@ -226,11 +231,8 @@ namespace SabreTools.Serialization
         /// <summary>
         /// Convert from <cref="Models.Internal.Rom"/> to <cref="Models.SeparatedValue.Row"/>
         /// </summary>
-        private static Row? ConvertFromInternalModel(Models.Internal.Rom? item, Models.Internal.Machine? parent)
+        private static Row ConvertFromInternalModel(Models.Internal.Rom item, Models.Internal.Machine parent)
         {
-            if (item == null)
-                return null;
-
             var row = new Row
             {
                 GameName = parent?.ReadString(Models.Internal.Machine.NameKey),

SabreTools.Serialization/SeparatedValue.Serializer.cs

@@ -133,8 +133,11 @@ namespace SabreTools.Serialization
         /// <summary>
         /// Convert from <cref="Models.SeparatedValue.MetadataFile"/> to <cref="Models.Internal.MetadataFile"/>
         /// </summary>
-        public static Models.Internal.MetadataFile ConvertToInternalModel(MetadataFile item)
+        public static Models.Internal.MetadataFile? ConvertToInternalModel(MetadataFile? item)
         {
+            if (item == null)
+                return null;
+
             var metadataFile = new Models.Internal.MetadataFile
             {
                 [Models.Internal.MetadataFile.HeaderKey] = ConvertHeaderToInternalModel(item),

SabreTools.Serialization/SoftwareList.Deserializer.cs

@@ -23,7 +23,12 @@ namespace SabreTools.Serialization
 
             var machines = item.Read<Models.Internal.Machine[]>(Models.Internal.MetadataFile.MachineKey);
             if (machines != null && machines.Any())
-                metadataFile.Software = machines.Select(ConvertMachineFromInternalModel).ToArray();
+            {
+                metadataFile.Software = machines
+                    .Where(m => m != null)
+                    .Select(ConvertMachineFromInternalModel)
+                    .ToArray();
+            }
 
             return metadataFile;
         }
@@ -31,11 +36,8 @@ namespace SabreTools.Serialization
         /// <summary>
         /// Convert from <cref="Models.Internal.Header"/> to <cref="Models.SoftwareList.SoftwareList"/>
         /// </summary>
-        private static SoftwareList? ConvertHeaderFromInternalModel(Models.Internal.Header? item)
+        private static SoftwareList ConvertHeaderFromInternalModel(Models.Internal.Header item)
         {
-            if (item == null)
-                return null;
-
             var softwareList = new SoftwareList
             {
                 Name = item.ReadString(Models.Internal.Header.NameKey),
@@ -48,11 +50,8 @@ namespace SabreTools.Serialization
         /// <summary>
         /// Convert from <cref="Models.Internal.Machine"/> to <cref="Models.SoftwareList.Software"/>
         /// </summary>
-        private static Software? ConvertMachineFromInternalModel(Models.Internal.Machine? item)
+        private static Software ConvertMachineFromInternalModel(Models.Internal.Machine item)
         {
-            if (item == null)
-                return null;
-            
             var software = new Software
             {
                 Name = item.ReadString(Models.Internal.Machine.NameKey),
@@ -65,13 +64,31 @@ namespace SabreTools.Serialization
             };
 
             var infos = item.Read<Models.Internal.Info[]>(Models.Internal.Machine.InfoKey);
-            software.Info = infos?.Select(ConvertFromInternalModel)?.ToArray();
+            if (infos != null && infos.Any())
+            {
+                software.Info = infos
+                    .Where(i => i != null)
+                    .Select(ConvertFromInternalModel)
+                    .ToArray();
+            }
 
             var sharedFeats = item.Read<Models.Internal.SharedFeat[]>(Models.Internal.Machine.SharedFeatKey);
-            software.SharedFeat = sharedFeats?.Select(ConvertFromInternalModel)?.ToArray();
+            if (sharedFeats != null && sharedFeats.Any())
+            {
+                software.SharedFeat = sharedFeats
+                    .Where(s => s != null)
+                    .Select(ConvertFromInternalModel)
+                    .ToArray();
+            }
 
             var parts = item.Read<Models.Internal.Part[]>(Models.Internal.Machine.PartKey);
-            software.Part = parts?.Select(ConvertFromInternalModel)?.ToArray();
+            if (parts != null && parts.Any())
+            {
+                software.Part = parts
+                    .Where(p => p != null)
+                    .Select(ConvertFromInternalModel)
+                    .ToArray();
+            }
 
             return software;
         }
@@ -79,11 +96,8 @@ namespace SabreTools.Serialization
         /// <summary>
         /// Convert from <cref="Models.Internal.DataArea"/> to <cref="Models.SoftwareList.DataArea"/>
         /// </summary>
-        private static DataArea? ConvertFromInternalModel(Models.Internal.DataArea? item)
+        private static DataArea ConvertFromInternalModel(Models.Internal.DataArea item)
         {
-            if (item == null)
-                return null;
-            
             var dataArea = new DataArea
             {
                 Name = item.ReadString(Models.Internal.DataArea.NameKey),
@@ -93,7 +107,13 @@ namespace SabreTools.Serialization
             };
 
             var roms = item.Read<Models.Internal.Rom[]>(Models.Internal.DataArea.RomKey);
-            dataArea.Rom = roms?.Select(ConvertFromInternalModel)?.ToArray();
+            if (roms != null && roms.Any())
+            {
+                dataArea.Rom = roms
+                    .Where(r => r != null)
+                    .Select(ConvertFromInternalModel)
+                    .ToArray();
+            }
 
             return dataArea;
         }
@@ -101,11 +121,8 @@ namespace SabreTools.Serialization
         /// <summary>
         /// Convert from <cref="Models.Internal.DipSwitch"/> to <cref="Models.SoftwareList.DipSwitch"/>
         /// </summary>
-        private static DipSwitch? ConvertFromInternalModel(Models.Internal.DipSwitch? item)
+        private static DipSwitch ConvertFromInternalModel(Models.Internal.DipSwitch item)
         {
-            if (item == null)
-                return null;
-            
             var dipSwitch = new DipSwitch
             {
                 Name = item.ReadString(Models.Internal.DipSwitch.NameKey),
@@ -114,7 +131,13 @@ namespace SabreTools.Serialization
             };
 
             var dipValues = item.Read<Models.Internal.DipValue[]>(Models.Internal.DipSwitch.DipValueKey);
-            dipSwitch.DipValue = dipValues?.Select(ConvertFromInternalModel)?.ToArray();
+            if (dipValues != null && dipValues.Any())
+            {
+                dipSwitch.DipValue = dipValues
+                    .Where(d => d != null)
+                    .Select(ConvertFromInternalModel)
+                    .ToArray();
+            }
 
             return dipSwitch;
         }
@@ -122,11 +145,8 @@ namespace SabreTools.Serialization
         /// <summary>
         /// Convert from <cref="Models.Internal.DipValue"/> to <cref="Models.SoftwareList.DipValue"/>
         /// </summary>
-        private static DipValue? ConvertFromInternalModel(Models.Internal.DipValue? item)
+        private static DipValue ConvertFromInternalModel(Models.Internal.DipValue item)
         {
-            if (item == null)
-                return null;
-            
             var dipValue = new DipValue
             {
                 Name = item.ReadString(Models.Internal.DipValue.NameKey),
@@ -139,11 +159,8 @@ namespace SabreTools.Serialization
         /// <summary>
         /// Convert from <cref="Models.Internal.Disk"/> to <cref="Models.SoftwareList.Disk"/>
         /// </summary>
-        private static Disk? ConvertFromInternalModel(Models.Internal.Disk? item)
+        private static Disk ConvertFromInternalModel(Models.Internal.Disk item)
         {
-            if (item == null)
-                return null;
-            
             var disk = new Disk
             {
                 Name = item.ReadString(Models.Internal.Disk.NameKey),
@@ -158,18 +175,21 @@ namespace SabreTools.Serialization
         /// <summary>
         /// Convert from <cref="Models.Internal.DiskArea"/> to <cref="Models.SoftwareList.DiskArea"/>
         /// </summary>
-        private static DiskArea? ConvertFromInternalModel(Models.Internal.DiskArea? item)
+        private static DiskArea ConvertFromInternalModel(Models.Internal.DiskArea item)
         {
-            if (item == null)
-                return null;
-            
             var diskArea = new DiskArea
             {
                 Name = item.ReadString(Models.Internal.DiskArea.NameKey),
             };
 
             var disks = item.Read<Models.Internal.Disk[]>(Models.Internal.DiskArea.DiskKey);
-            diskArea.Disk = disks?.Select(ConvertFromInternalModel)?.ToArray();
+            if (disks != null && disks.Any())
+            {
+                diskArea.Disk = disks
+                    .Where(d => d != null)
+                    .Select(ConvertFromInternalModel)
+                    .ToArray();
+            }
 
             return diskArea;
         }
@@ -177,11 +197,8 @@ namespace SabreTools.Serialization
         /// <summary>
         /// Convert from <cref="Models.Internal.Feature"/> to <cref="Models.SoftwareList.Feature"/>
         /// </summary>
-        private static Feature? ConvertFromInternalModel(Models.Internal.Feature? item)
+        private static Feature ConvertFromInternalModel(Models.Internal.Feature item)
         {
-            if (item == null)
-                return null;
-            
             var feature = new Feature
             {
                 Name = item.ReadString(Models.Internal.Feature.NameKey),
@@ -193,11 +210,8 @@ namespace SabreTools.Serialization
         /// <summary>
         /// Convert from <cref="Models.Internal.Info"/> to <cref="Models.SoftwareList.Info"/>
         /// </summary>
-        private static Info? ConvertFromInternalModel(Models.Internal.Info? item)
+        private static Info ConvertFromInternalModel(Models.Internal.Info item)
         {
-            if (item == null)
-                return null;
-            
             var info = new Info
             {
                 Name = item.ReadString(Models.Internal.Info.NameKey),
@@ -209,11 +223,8 @@ namespace SabreTools.Serialization
         /// <summary>
         /// Convert from <cref="Models.Internal.Part"/> to <cref="Models.SoftwareList.Part"/>
         /// </summary>
-        private static Part? ConvertFromInternalModel(Models.Internal.Part? item)
+        private static Part ConvertFromInternalModel(Models.Internal.Part item)
         {
-            if (item == null)
-                return null;
-            
             var part = new Part
             {
                 Name = item.ReadString(Models.Internal.Part.NameKey),
@@ -221,16 +232,40 @@ namespace SabreTools.Serialization
             };
 
             var features = item.Read<Models.Internal.Feature[]>(Models.Internal.Part.FeatureKey);
-            part.Feature = features?.Select(ConvertFromInternalModel)?.ToArray();
+            if (features != null && features.Any())
+            {
+                part.Feature = features
+                    .Where(f => f != null)
+                    .Select(ConvertFromInternalModel)
+                    .ToArray();
+            }
 
             var dataAreas = item.Read<Models.Internal.DataArea[]>(Models.Internal.Part.DataAreaKey);
-            part.DataArea = dataAreas?.Select(ConvertFromInternalModel)?.ToArray();
+            if (dataAreas != null && dataAreas.Any())
+            {
+                part.DataArea = dataAreas
+                    .Where(d => d != null)
+                    .Select(ConvertFromInternalModel)
+                    .ToArray();
+            }
 
             var diskAreas = item.Read<Models.Internal.DiskArea[]>(Models.Internal.Part.DiskAreaKey);
-            part.DiskArea = diskAreas?.Select(ConvertFromInternalModel)?.ToArray();
+            if (diskAreas != null && diskAreas.Any())
+            {
+                part.DiskArea = diskAreas
+                    .Where(d => d != null)
+                    .Select(ConvertFromInternalModel)
+                    .ToArray();
+            }
 
             var dipSwitches = item.Read<Models.Internal.DipSwitch[]>(Models.Internal.Part.DipSwitchKey);
-            part.DipSwitch = dipSwitches?.Select(ConvertFromInternalModel)?.ToArray();
+            if (dipSwitches != null && dipSwitches.Any())
+            {
+                part.DipSwitch = dipSwitches
+                    .Where(d => d != null)
+                    .Select(ConvertFromInternalModel)
+                    .ToArray();
+            }
 
             return part;
         }
@@ -238,11 +273,8 @@ namespace SabreTools.Serialization
         /// <summary>
         /// Convert from <cref="Models.Internal.Rom"/> to <cref="Models.SoftwareList.Rom"/>
         /// </summary>
-        private static Rom? ConvertFromInternalModel(Models.Internal.Rom? item)
+        private static Rom ConvertFromInternalModel(Models.Internal.Rom item)
         {
-            if (item == null)
-                return null;
-            
             var rom = new Rom
             {
                 Name = item.ReadString(Models.Internal.Rom.NameKey),
@@ -261,11 +293,8 @@ namespace SabreTools.Serialization
         /// <summary>
         /// Convert from <cref="Models.Internal.SharedFeat"/> to <cref="Models.SoftwareList.SharedFeat"/>
         /// </summary>
-        private static SharedFeat? ConvertFromInternalModel(Models.Internal.SharedFeat? item)
+        private static SharedFeat ConvertFromInternalModel(Models.Internal.SharedFeat item)
         {
-            if (item == null)
-                return null;
-            
             var sharedFeat = new SharedFeat
             {
                 Name = item.ReadString(Models.Internal.SharedFeat.NameKey),

SabreTools.Serialization/SoftwareList.Serializer.cs

@@ -22,15 +22,23 @@ namespace SabreTools.Serialization
         /// <summary>
         /// Convert from <cref="Models.SoftwareList.SoftwareList"/> to <cref="Models.Internal.MetadataFile"/>
         /// </summary>
-        public static Models.Internal.MetadataFile ConvertToInternalModel(SoftwareList item)
+        public static Models.Internal.MetadataFile? ConvertToInternalModel(SoftwareList? item)
         {
+            if (item == null)
+                return null;
+
             var metadataFile = new Models.Internal.MetadataFile
             {
                 [Models.Internal.MetadataFile.HeaderKey] = ConvertHeaderToInternalModel(item),
             };
 
             if (item?.Software != null && item.Software.Any())
-                metadataFile[Models.Internal.MetadataFile.MachineKey] = item.Software.Select(ConvertMachineToInternalModel).ToArray();
+            {
+                metadataFile[Models.Internal.MetadataFile.MachineKey] = item.Software
+                    .Where(s => s != null)
+                    .Select(ConvertMachineToInternalModel)
+                    .ToArray();
+            }
 
             return metadataFile;
         }

SabreTools.Test/Serialization/DeserializationTests.cs

@@ -589,10 +589,10 @@ namespace SabreTools.Test.Parser
                     Assert.Null(item.ADDITIONAL_ELEMENTS);
                 }
 
-                foreach (var item in game.Driver ?? Array.Empty<Models.Logiqx.Driver>())
+                if (game.Driver != null)
                 {
-                    Assert.Null(item.ADDITIONAL_ATTRIBUTES);
+                    Assert.Null(game.Driver.ADDITIONAL_ATTRIBUTES);
-                    Assert.Null(item.ADDITIONAL_ELEMENTS);
+                    Assert.Null(game.Driver.ADDITIONAL_ELEMENTS);
                 }
 
                 foreach (var item in game.SoftwareList ?? Array.Empty<Models.Logiqx.SoftwareList>())
@@ -664,10 +664,10 @@ namespace SabreTools.Test.Parser
                     Assert.Null(item.ADDITIONAL_ELEMENTS);
                 }
 
-                foreach (var item in game.Driver ?? Array.Empty<Models.Logiqx.Driver>())
+                if (game.Driver != null)
                 {
-                    Assert.Null(item.ADDITIONAL_ATTRIBUTES);
+                    Assert.Null(game.Driver.ADDITIONAL_ATTRIBUTES);
-                    Assert.Null(item.ADDITIONAL_ELEMENTS);
+                    Assert.Null(game.Driver.ADDITIONAL_ELEMENTS);
                 }
 
                 foreach (var item in game.SoftwareList ?? Array.Empty<Models.Logiqx.SoftwareList>())