From ab44aa7e68c87c41ca8c92fd6c5107f3a404d1a4 Mon Sep 17 00:00:00 2001
From: Matt Nadareski <mnadareski@outlook.com>
Date: Thu, 28 Aug 2025 08:14:38 -0400
Subject: [PATCH] Start implementing tar

---
 .../Deserializers/TapeArchive.cs              | 104 +++++++++++++++++-
 1 file changed, 103 insertions(+), 1 deletion(-)

diff --git a/SabreTools.Serialization/Deserializers/TapeArchive.cs b/SabreTools.Serialization/Deserializers/TapeArchive.cs
index 56a6fd22..46b95ccc 100644
--- a/SabreTools.Serialization/Deserializers/TapeArchive.cs
+++ b/SabreTools.Serialization/Deserializers/TapeArchive.cs
@@ -1,4 +1,7 @@
+using System.Collections.Generic;
 using System.IO;
+using System.Text;
+using SabreTools.IO.Extensions;
 using SabreTools.Models.TAR;
 
 namespace SabreTools.Serialization.Deserializers
@@ -22,7 +25,19 @@ namespace SabreTools.Serialization.Deserializers
 
                 var archive = new Archive();
 
-                // TODO: Implement everything
+                // Read all entries sequentially
+                List<Entry> entries = [];
+                while (data.Position < data.Length)
+                {
+                    var entry = ParseEntry(data);
+                    if (entry == null)
+                        break;
+
+                    entries.Add(entry);
+                }
+
+                // Assign the entries
+                archive.Entries = [.. entries];
 
                 return archive;
             }
@@ -32,5 +47,92 @@ namespace SabreTools.Serialization.Deserializers
                 return null;
             }
         }
+
+        /// <summary>
+        /// Parse a Stream into an Entry
+        /// </summary>
+        /// <param name="data">Stream to parse</param>
+        /// <returns>Filled Entry on success, null on error</returns>
+        public static Entry? ParseEntry(Stream data)
+        {
+            var obj = new Entry();
+
+            #region Header
+
+            var header = ParseHeader(data);
+            if (header == null)
+                return null;
+
+            obj.Header = header;
+
+            #endregion
+
+            #region Blocks
+
+            List<Block> blocks = [];
+
+            // TODO: Implement
+            // Each block is 512 bytes of data. The size in the entry
+            // header is in octal string representation. To the best
+            // of my knowledge, the number of blocks is just the
+            // ceiling(size / 512). That is going to be how this is
+            // implemented.
+
+            obj.Blocks = [.. blocks];
+
+            #endregion
+
+            return obj;
+        }
+
+        /// <summary>
+        /// Parse a Stream into a Header
+        /// </summary>
+        /// <param name="data">Stream to parse</param>
+        /// <returns>Filled Header on success, null on error</returns>
+        public static Header? ParseHeader(Stream data)
+        {
+            var obj = new Header();
+
+            byte[] filenameBytes = data.ReadBytes(100);
+            obj.FileName = Encoding.ASCII.GetString(filenameBytes);
+            obj.Mode = data.ReadBytes(8);
+            obj.UID = data.ReadBytes(8);
+            obj.GID = data.ReadBytes(8);
+            obj.Size = data.ReadBytes(12);
+            obj.ModifiedTime = data.ReadBytes(12);
+            obj.Checksum = data.ReadBytes(8);
+            obj.TypeFlag = (TypeFlag)data.ReadByteValue();
+            byte[] linkNameBytes = data.ReadBytes(100);
+            obj.LinkName = Encoding.ASCII.GetString(linkNameBytes);
+
+            // If end of stream has been reached
+            if (data.Position >= data.Length)
+                return obj;
+
+            // Peek at the next 6 bytes
+            byte[] temp = data.ReadBytes(6);
+            string tempString = Encoding.ASCII.GetString(temp);
+            data.Seek(-6, SeekOrigin.Current);
+            if (tempString != "ustar\0")
+                return obj;
+
+            byte[] magicBytes = data.ReadBytes(6);
+            obj.Magic = Encoding.ASCII.GetString(magicBytes);
+            byte[] versionBytes = data.ReadBytes(3);
+            obj.Version = Encoding.ASCII.GetString(versionBytes);
+            byte[] userNameBytes = data.ReadBytes(32);
+            obj.UserName = Encoding.ASCII.GetString(userNameBytes);
+            byte[] groupNameBytes = data.ReadBytes(32);
+            obj.GroupName = Encoding.ASCII.GetString(groupNameBytes);
+            byte[] devMajorBytes = data.ReadBytes(8);
+            obj.DevMajor = Encoding.ASCII.GetString(devMajorBytes);
+            byte[] devMinorBytes = data.ReadBytes(8);
+            obj.DevMinor = Encoding.ASCII.GetString(devMinorBytes);
+            byte[] prefixBytes = data.ReadBytes(155);
+            obj.Prefix = Encoding.ASCII.GetString(prefixBytes);
+
+            return obj;
+        }
     }
 }