From b4d3ca64f3c148ea0dcaccbc419010e2f0b64ed6 Mon Sep 17 00:00:00 2001
From: YeLike <93629620+YeLikesss@users.noreply.github.com>
Date: Wed, 22 Apr 2026 18:50:51 +0800
Subject: [PATCH] =?UTF-8?q?[NekoNovel]=20=E6=94=AF=E6=8C=81?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 ArcFormats/ArcFormats.csproj      |  1 +
 ArcFormats/NekoNovel/ArcNKPACK.cs | 94 +++++++++++++++++++++++++++++++
 2 files changed, 95 insertions(+)
 create mode 100644 ArcFormats/NekoNovel/ArcNKPACK.cs

diff --git a/ArcFormats/ArcFormats.csproj b/ArcFormats/ArcFormats.csproj
index 2aa2aa8c..8b715459 100644
--- a/ArcFormats/ArcFormats.csproj
+++ b/ArcFormats/ArcFormats.csproj
@@ -265,6 +265,7 @@
     <Compile Include="MAGES\ImageBIN.cs" />
     <Compile Include="Mugi\ArcBIN.cs" />
     <Compile Include="Musica\ArcPAK.cs" />
+    <Compile Include="NekoNovel\ArcNKPACK.cs" />
     <Compile Include="NEKOWORKs\ArcPACK.cs" />
     <Compile Include="NipponIchi\ArcCASN.cs" />
     <Compile Include="NipponIchi\ArcPSFS.cs" />
diff --git a/ArcFormats/NekoNovel/ArcNKPACK.cs b/ArcFormats/NekoNovel/ArcNKPACK.cs
new file mode 100644
index 00000000..0519d21d
--- /dev/null
+++ b/ArcFormats/NekoNovel/ArcNKPACK.cs
@@ -0,0 +1,94 @@
+using System;
+using System.IO;
+using System.Collections.Generic;
+using System.Text;
+using GameRes.Compression;
+using System.ComponentModel.Composition;
+using CommunityToolkit.HighPerformance;
+
+namespace GameRes.Formats.NekoNovel
+{
+    [Export(typeof(ArchiveFormat))]
+    public class NkpackOpener : ArchiveFormat
+    {
+        public override string Tag => "NKPACK/NekoNovel";
+        public override string Description => "NekoNovel resource archive";
+        public override uint Signature => 0u;
+        public override bool IsHierarchic => true;
+        public override bool CanWrite => false;
+
+        public NkpackOpener()
+        {
+            Extensions = new string[] { "nkpack" };
+        }
+
+        private static readonly byte[] s_mHeader = new byte[]
+        {
+            0x0F, 0x00, 0x00, 0x00, 0x4E, 0x4B, 0x4E, 0x4F, 0x45, 0x56, 0x4C, 0x20, 0x50, 0x41, 0x43, 0x4B,
+            0x41, 0x47, 0x45
+        };
+
+        public override ArcFile TryOpen(ArcView file)
+        {
+            if (!file.View.BytesEqual(0L, s_mHeader))
+            {
+                return null;
+            }
+            using (ArcViewStream stream = file.CreateStream())
+            {
+                stream.Seek(-4L, SeekOrigin.End);
+                uint entryOffset = ~stream.ReadUInt32();
+
+                stream.Seek(entryOffset, SeekOrigin.Begin);
+                string signature = ReadString(stream);
+
+                int count = stream.ReadInt32();
+                List<Entry> entries = new List<Entry>(count);
+                for (int i = 0; i < count; ++i)
+                {
+                    string name = ReadString(stream);
+
+                    PackedEntry entry = Create<PackedEntry>(name);
+                    entry.Offset = ~stream.ReadUInt32();
+                    entry.UnpackedSize = stream.ReadUInt32();
+                    entry.Size = ~stream.ReadUInt32();
+                    entry.IsPacked = true;
+
+                    if (!entry.CheckPlacement(file.MaxOffset))
+                    { 
+                        return null;
+                    }
+
+                    entries.Add(entry);
+                }
+
+                return new ArcFile(file, this, entries);
+            }
+        }
+
+        public override Stream OpenEntry(ArcFile arc, Entry entry)
+        {
+            if (!(entry is PackedEntry e))
+            {
+                return arc.File.CreateStream(entry.Offset, entry.Size);
+            }
+            return new ZLibStream(arc.File.CreateStream(e.Offset, e.Size), CompressionMode.Decompress);
+        }
+
+        private unsafe static string ReadString(Stream stream)
+        {
+            uint length = 0u;
+            stream.Read(new Span<byte>(&length, 4));
+
+            if (length == 0u)
+            {
+                return string.Empty;
+            }
+
+            byte[] data = new byte[length];
+            stream.Read(data, 0, data.Length);
+
+            return Encoding.UTF8.GetString(data);
+        }
+    }
+}