Add support for freeform tags

AAXClean.nuspec

@@ -18,7 +18,7 @@
 	</metadata>
 	<dependencies>
 		<group targetFramework="net6.0">
-			<dependency id="Mpeg4Lib" version="0.1.12" />
+			<dependency id="Mpeg4Lib" version="0.1.20" />
 		</group>
 	</dependencies>
 	<files>

src/AAXClean/AAXClean.csproj

@@ -2,7 +2,7 @@
 
   <PropertyGroup>
     <TargetFramework>net6.0</TargetFramework>
-    <Version>1.0.3</Version>
+    <Version>1.1.0</Version>
     <Authors>MrGneissGuy</Authors>
     <Company>Just Me, Inc.</Company>
     <Description>Decrypts Audible aax and aaxc files to mp4.</Description>

src/Mpeg4Lib/Boxes/AdrmBox.cs

@@ -18,7 +18,7 @@ public AdrmBox(Stream file, BoxHeader header, IBox parent) : base(header, parent
 			DrmBlob = file.ReadBlock(56);
 			middleBlob = file.ReadBlock(4);
 			Checksum = file.ReadBlock(20);
-			long len = Header.FilePosition + Header.TotalBoxSize - file.Position;
+			long len = RemainingBoxLength(file);
 			endBlob = file.ReadBlock((int)len);
 		}
 

src/Mpeg4Lib/Boxes/AppleDataBox.cs

@@ -29,7 +29,7 @@ public AppleDataBox(Stream file, BoxHeader header, IBox parent) : base(header, p
 		{
 			DataType = (AppleDataType)file.ReadUInt32BE();
 			Flags = file.ReadUInt32BE();
-			long length = Header.FilePosition + Header.TotalBoxSize - file.Position;
+			long length = RemainingBoxLength(file);
 			Data = file.ReadBlock((int)length);
 		}
 		protected override void Render(Stream file)

src/Mpeg4Lib/Boxes/AppleListBox.cs

@@ -13,10 +13,16 @@ public AppleListBox(Stream file, BoxHeader header, IBox parent) : base(header, p
 
 			while (file.Position < endPos)
 			{
-				AppleTagBox appleTag = new AppleTagBox(file, new BoxHeader(file), this);
+				BoxHeader tagBoxHeader = new BoxHeader(file);
+
+				AppleTagBox appleTag
+					= tagBoxHeader.Type == "----"
+					? new FreeformTagBox(file, tagBoxHeader, this)
+					: new AppleTagBox(file, tagBoxHeader, this);
 
 				if (appleTag.Header.TotalBoxSize == 0)
 					break;
+
 				Children.Add(appleTag);
 			}
 		}
@@ -33,7 +39,7 @@ public void AddTag(string name, string data)
 		public void AddTag(string name, byte[] data, AppleDataType type)
 		{
 			AppleTagBox.Create(this, name, data, type);
-		}		
+		}
 
 		public void EditOrAddTag(string name, string data)
 		{
@@ -59,6 +65,44 @@ public void EditOrAddTag(string name, byte[] data, AppleDataType type)
 			}
 		}
 
+		public void AddFreeformTag(string domain, string name, string data)
+		{
+			FreeformTagBox.Create(this, domain, name, Encoding.UTF8.GetBytes(data), AppleDataType.Utf_8);
+		}
+
+		public void AddFreeformTag(string domain, string name, byte[] data, AppleDataType type)
+		{
+			FreeformTagBox.Create(this, domain, name, data, type);
+		}
+
+		public void EditOrAddFreeformTag(string domain, string name, string data)
+		{
+			EditOrAddFreeformTag(domain, name, Encoding.UTF8.GetBytes(data), AppleDataType.Utf_8);
+		}
+
+		public void EditOrAddFreeformTag(string domain, string name, byte[] data)
+		{
+			EditOrAddFreeformTag(domain, name, data, AppleDataType.ContainsData);
+		}
+
+		public void EditOrAddFreeformTag(string domain, string name, byte[] data, AppleDataType type)
+		{
+			FreeformTagBox tag
+				= Tags
+				.OfType<FreeformTagBox>()
+				.Where(t => t.Mean.ReverseDnsDomain == domain && t.Name.Name == name)
+				.FirstOrDefault();
+
+			if (tag is null)
+			{
+				AddFreeformTag(domain, name, data, type);
+			}
+			else if (tag?.Data.DataType == type)
+			{
+				tag.Data.Data = data;
+			}
+		}
+
 		public string GetTagString(string name)
 		{
 			byte[] tag = GetTagBytes(name);
@@ -72,6 +116,22 @@ public byte[] GetTagBytes(string name)
 			.Where(t => t.Header.Type == name)
 			.FirstOrDefault()
 			?.GetChild<AppleDataBox>()
-			?.Data;		
+			?.Data;
+
+		public string GetFreeformTagString(string domain, string name)
+		{
+			byte[] tag = GetFreeformTagBytes(domain, name);
+			if (tag is null) return null;
+
+			return Encoding.UTF8.GetString(tag);
+		}
+
+		public byte[] GetFreeformTagBytes(string domain, string name)
+			=> Tags
+			.OfType<FreeformTagBox>()
+			.Where(t => t.Mean.ReverseDnsDomain == domain && t.Name.Name == name)
+			.FirstOrDefault()
+			?.GetChild<AppleDataBox>()
+			?.Data;
 	}
 }

src/Mpeg4Lib/Boxes/AppleTagBox.cs

@@ -1,21 +1,27 @@
-using System.IO;
+using System;
+using System.IO;
+using System.Text;
 
 namespace Mpeg4Lib.Boxes
 {
 	public class AppleTagBox : Box
 	{
-		public static void Create(AppleListBox parent, string name, byte[] data, AppleDataType dataType)
+		public static AppleTagBox Create(AppleListBox parent, string name, byte[] data, AppleDataType dataType)
 		{
+			if (Encoding.ASCII.GetByteCount(name) != 4)
+				throw new ArgumentOutOfRangeException($"{nameof(name)} must be exactly 4 bytes long");
+
 			int size = data.Length + 2 + 8 /* empty Box size*/ ;
 			BoxHeader header = new BoxHeader((uint)size, name);
 
 			AppleTagBox tagBox = new AppleTagBox(header, parent);
 			AppleDataBox.Create(tagBox, data, dataType);
 
 			parent.Children.Add(tagBox);
+			return tagBox;
 		}
 
-		private AppleTagBox(BoxHeader header, IBox parent) : base(header, parent) { }
+		protected AppleTagBox(BoxHeader header, IBox parent) : base(header, parent) { }
 
 		public AppleTagBox(Stream file, BoxHeader header, IBox parent) : base(header, parent)
 		{

src/Mpeg4Lib/Boxes/Box.cs

@@ -13,6 +13,8 @@ public abstract class Box : IBox
 		public List<IBox> Children { get; } = new List<IBox>();
 		public virtual long RenderSize => 8 + Children.Sum(b => b.RenderSize);
 
+		protected long RemainingBoxLength(Stream file) => Header.FilePosition + Header.TotalBoxSize - file.Position;
+
 		public Box(BoxHeader header, IBox parent)
 		{
 			Header = header;

src/Mpeg4Lib/Boxes/BoxFactory.cs

@@ -36,6 +36,8 @@ public static IBox CreateBox(Stream file, IBox parent)
 				"meta" => new MetaBox(file, header, parent),
 				"ilst" => new AppleListBox(file, header, parent),
 				"data" => new AppleDataBox(file, header, parent),
+				"mean" => new MeanBox(file, header, parent),
+				"name" => new NameBox(file, header, parent),
 				_ => new UnknownBox(file, header, parent),
 			};
 		}

src/Mpeg4Lib/Boxes/FreeformTagBox.cs

@@ -0,0 +1,37 @@
+using System.IO;
+using System.Text;
+
+namespace Mpeg4Lib.Boxes
+{
+	//https://mutagen.readthedocs.io/en/latest/api/mp4.html
+	public class FreeformTagBox : AppleTagBox
+	{
+		public MeanBox Mean => GetChild<MeanBox>();
+		public NameBox Name => GetChild<NameBox>();
+
+		public static FreeformTagBox Create(AppleListBox parent, string domain, string tagName, byte[] data, AppleDataType dataType)
+		{
+			int size
+				= 12 /* empty FullBox size*/ + Encoding.UTF8.GetByteCount(domain)
+				+ 12 /* empty FullBox size*/ + Encoding.UTF8.GetByteCount(tagName)
+				+ 8 /* empty Box size*/ + data.Length + 2;
+
+			BoxHeader header = new BoxHeader((uint)size, "----");
+
+			var tagBox = new FreeformTagBox(header, parent);
+			MeanBox.Create(tagBox, domain);
+			NameBox.Create(tagBox, tagName);
+			AppleDataBox.Create(tagBox, data, dataType);
+
+			parent.Children.Add(tagBox);
+			return tagBox;
+		}
+
+		protected FreeformTagBox(BoxHeader header, IBox parent) : base(header, parent) { }
+
+		public FreeformTagBox(Stream file, BoxHeader header, IBox parent) : base(header, parent)
+		{
+			LoadChildren(file);
+		}
+	}
+}

src/Mpeg4Lib/Boxes/MeanBox.cs

@@ -0,0 +1,39 @@
+using Mpeg4Lib.Util;
+using System.IO;
+using System.Text;
+
+namespace Mpeg4Lib.Boxes
+{
+	public class MeanBox : FullBox
+	{
+		public override long RenderSize => base.RenderSize + Encoding.UTF8.GetByteCount(ReverseDnsDomain);
+		public string ReverseDnsDomain { get; set; }
+		public MeanBox(Stream file, BoxHeader header, IBox parent) : base(file, header, parent)
+		{
+			var stringSize = RemainingBoxLength(file);
+			var stringData = file.ReadBlock((int)stringSize);
+			ReverseDnsDomain = Encoding.UTF8.GetString(stringData);
+		}
+
+		public static void Create(IBox parent, string domain)
+		{
+			int size = Encoding.UTF8.GetByteCount(domain) + 12 /* empty FullBox size*/;
+			BoxHeader header = new BoxHeader((uint)size, "mean");
+
+			MeanBox meanBox = new MeanBox(header, parent, domain);
+
+			parent.Children.Add(meanBox);
+		}
+
+		private MeanBox(BoxHeader header, IBox parent, string domain) : base(new byte[4], header, parent)
+		{
+			ReverseDnsDomain = domain;
+		}
+
+		protected override void Render(Stream file)
+		{
+			base.Render(file);
+			file.Write(Encoding.UTF8.GetBytes(ReverseDnsDomain));
+		}
+	}
+}

src/Mpeg4Lib/Boxes/NameBox.cs

@@ -0,0 +1,39 @@
+using Mpeg4Lib.Util;
+using System.IO;
+using System.Text;
+
+namespace Mpeg4Lib.Boxes
+{
+	public class NameBox : FullBox
+	{
+		public override long RenderSize => base.RenderSize + Encoding.UTF8.GetByteCount(Name);
+		public string Name { get; set; }
+		public NameBox(Stream file, BoxHeader header, IBox parent) : base(file, header, parent)
+		{
+			var stringSize = RemainingBoxLength(file);
+			var stringData = file.ReadBlock((int)stringSize);
+			Name = Encoding.UTF8.GetString(stringData);
+		}
+
+		public static void Create(IBox parent, string name)
+		{
+			int size = Encoding.UTF8.GetByteCount(name) + 12 /* empty FullBox size*/;
+			BoxHeader header = new BoxHeader((uint)size, "name");
+
+			NameBox nameBox = new NameBox(header, parent, name);
+
+			parent.Children.Add(nameBox);
+		}
+
+		private NameBox(BoxHeader header, IBox parent, string name) : base(new byte[4], header, parent)
+		{
+			Name = name;
+		}
+
+		protected override void Render(Stream file)
+		{
+			base.Render(file);
+			file.Write(Encoding.UTF8.GetBytes(Name));
+		}
+	}
+}

src/Mpeg4Lib/Mpeg4Lib.csproj

@@ -2,7 +2,7 @@
 
   <PropertyGroup>
     <TargetFramework>net6.0</TargetFramework>
-	  <Version>0.1.12</Version>
+	  <Version>0.1.2</Version>
 	  <Authors>MrGneissGuy</Authors>
 	  <Company>Just Me, Inc.</Company>
 	  <Description>Parsees mpeg-4 files</Description>