Very early SevenZip WIP version

ROMVault2/SupportedFiles/SevenZip/Structure/Header.cs

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+using System;
+using System.IO;
+using ROMVault2.SupportedFiles.SevenZip.Compress.LZMA;
+
+namespace ROMVault2.SupportedFiles.SevenZip.Structure
+{
+    public class Header
+    {
+        public StreamsInfo StreamsInfo;
+        public FileInfo FileInfo;
+
+        public void Read(BinaryReader br)
+        {
+            Util.log("Begin : ReadHeader", 1);
+            for (; ; )
+            {
+                HeaderProperty hp = (HeaderProperty)br.ReadByte();
+                Util.log("HeaderProperty = " + hp);
+                switch (hp)
+                {
+                    case HeaderProperty.kMainStreamsInfo:
+                        StreamsInfo = new StreamsInfo();
+                        StreamsInfo.Read(br);
+                        break;
+
+                    case HeaderProperty.kFilesInfo:
+                        FileInfo = new FileInfo();
+                        FileInfo.Read(br);
+                        break;
+
+                    case HeaderProperty.kEnd:
+                        Util.log("End : ReadHeader", -1);
+                        return;
+
+                    default:
+                        throw new Exception(hp.ToString());
+                }
+            }
+        }
+
+
+        private void Write(BinaryWriter bw)
+        {
+            bw.Write((byte)HeaderProperty.kHeader);
+            StreamsInfo.Write(bw);
+            FileInfo.Write(bw);
+            bw.Write((byte)HeaderProperty.kEnd);
+        }
+
+        public void WriteHeader(BinaryWriter bw)
+        {
+            Write(bw);
+        }
+
+        public static ZipReturn ReadHeaderOrPackedHeader(Stream stream, long baseOffset, out Header header)
+        {
+            header = null;
+            Util.log("Begin : ReadHeaderOrPackedHeader", 1);
+
+            BinaryReader br = new BinaryReader(stream);
+
+            HeaderProperty hp = (HeaderProperty)br.ReadByte();
+            Util.log("HeaderProperty = " + hp);
+            switch (hp)
+            {
+                case HeaderProperty.kEncodedHeader:
+                    {
+                        StreamsInfo streamsInfo = new StreamsInfo();
+                        streamsInfo.Read(br);
+
+                        if (streamsInfo.Folders.Length > 1)
+                            return ZipReturn.ZipUnsupportedCompression;
+
+                        Folder firstFolder = streamsInfo.Folders[0];
+                        if (firstFolder.Coders.Length > 1)
+                            return ZipReturn.ZipUnsupportedCompression;
+
+                        byte[] method = firstFolder.Coders[0].Method;
+                        if (!(method.Length == 3 && method[0] == 3 && method[1] == 1 && method[2] == 1))  // LZMA
+                            return ZipReturn.ZipUnsupportedCompression;
+
+                        stream.Seek(baseOffset + (long)streamsInfo.PackPosition, SeekOrigin.Begin);
+                        using (Decoder decoder = new Decoder())
+                        {
+                            decoder.SetDecoderProperties(firstFolder.Coders[0].Properties);
+                            decoder.SetUpStream(stream);
+                            ZipReturn zr = ReadHeaderOrPackedHeader(decoder, baseOffset, out header);
+                            if (zr != ZipReturn.ZipGood)
+                                return zr;
+                        }
+                        Util.log("End : ReadHeaderOrPackedHeader (Packed)", -1);
+                        return ZipReturn.ZipGood;
+                    }
+                case HeaderProperty.kHeader:
+                    {
+                        header = new Header();
+                        header.Read(br);
+                        Util.log("End : ReadHeaderOrPackedHeader (UnPacked)", -1);
+                        return ZipReturn.ZipGood;
+                    }
+            }
+
+            return ZipReturn.ZipCenteralDirError;
+        }
+
+
+
+
+
+    }
+}