Add an NRO reader (#44)

src/LibHac/Nro.cs

@@ -0,0 +1,154 @@
+using System.IO;
+using LibHac.IO;
+
+namespace LibHac
+{
+    public class Nro
+    {
+        public NroStart Start { get; }
+        public NroHeader Header { get; }
+        public NroAssetHeader AssetHeader { get; }
+        private IStorage Storage { get; }
+        private IStorage AssetStorage { get; }
+
+        public Nro(IStorage storage)
+        {
+            Storage = storage;
+            var reader = new BinaryReader(Storage.AsStream());
+            Start = new NroStart(reader);
+            Header = new NroHeader(reader);
+
+            if (Header.Magic != "NRO0")
+                throw new InvalidDataException("NRO0 magic is incorrect!");
+
+            if (Header.Size < Storage.GetSize())
+            {
+                AssetStorage = Storage.Slice(Header.Size);
+                var assetReader = new BinaryReader(AssetStorage.AsStream());
+
+                AssetHeader = new NroAssetHeader(assetReader);
+                if (AssetHeader.Magic != "ASET")
+                    throw new InvalidDataException("ASET magic is incorrect!");
+            }
+        }
+
+        public IStorage OpenNroSegment(NroSegmentType type, bool leaveOpen)
+        {
+            NroSegment segment = Header.NroSegments[(int)type];
+
+            if (segment.Size <= 0) return new NullStorage(0);
+
+            return Storage.Slice(segment.FileOffset, segment.Size, leaveOpen);
+        }
+
+        public IStorage OpenNroAssetSection(NroAssetType type, bool leaveOpen)
+        {
+            NroAssetSection header = AssetHeader.NroAssetSections[(int)type];
+
+            if (header.Size <= 0) return new NullStorage(0);
+
+            return AssetStorage.Slice(header.FileOffset, header.Size, leaveOpen);
+        }
+
+    }
+
+    public class NroStart
+    {
+        public int Mod0Offset { get; }
+
+        public NroStart(BinaryReader reader)
+        {
+            reader.BaseStream.Position += 4;
+            Mod0Offset = reader.ReadInt32();
+            reader.BaseStream.Position += 8;
+        }
+    }
+
+    public class NroHeader
+    {
+        public string Magic { get; }
+        public uint Version { get; }
+        public uint Size { get; }
+        public uint BssSize { get; }
+        public byte[] BuildId { get; }
+
+        public NroSegment[] NroSegments { get; } = new NroSegment[0x3];
+
+        public NroHeader(BinaryReader reader)
+        {
+            Magic = reader.ReadAscii(4);
+            Version = reader.ReadUInt32();
+            Size = reader.ReadUInt32();
+            reader.BaseStream.Position += 4;
+
+            for (int i = 0; i < 3; i++)
+            {
+                NroSegments[i] = new NroSegment(reader, (NroSegmentType)i);
+            }
+
+            BssSize = reader.ReadUInt32();
+            reader.BaseStream.Position += 4;
+            BuildId = reader.ReadBytes(0x20);
+            reader.BaseStream.Position += 0x20;
+        }
+    }
+
+    public enum NroSegmentType
+    {
+        Text = 0,
+        Ro,
+        Data
+    }
+
+    public class NroSegment
+    {
+        public NroSegmentType Type { get; }
+        public uint FileOffset { get; }
+        public uint Size { get; }
+
+        public NroSegment(BinaryReader reader, NroSegmentType type)
+        {
+            Type = type;
+            FileOffset = reader.ReadUInt32();
+            Size = reader.ReadUInt32();
+        }
+    }
+
+    public class NroAssetHeader
+    {
+        public string Magic { get; }
+        public uint Version { get; }
+        public NroAssetSection[] NroAssetSections { get; } = new NroAssetSection[0x3];
+
+        public NroAssetHeader(BinaryReader reader)
+        {
+            Magic = reader.ReadAscii(4);
+            Version = reader.ReadUInt32();
+            for (int i = 0; i < 3; i++)
+            {
+                NroAssetSections[i] = new NroAssetSection(reader, (NroAssetType)i);
+            }
+        }
+    }
+
+    public enum NroAssetType
+    {
+        Icon = 0,
+        Nacp,
+        RomFs
+    }
+
+    public class NroAssetSection
+    {
+        public NroAssetType Type { get; }
+        public uint FileOffset { get; }
+        public uint Size { get; }
+
+        public NroAssetSection(BinaryReader reader, NroAssetType type)
+        {
+            Type = type;
+            FileOffset = (uint)reader.ReadUInt64();
+            Size = (uint)reader.ReadUInt64();
+        }
+    }
+}