diff --git a/ArcFormats/ArcAMI.cs b/ArcFormats/ArcAMI.cs
index 5202940e..43e56b8f 100644
--- a/ArcFormats/ArcAMI.cs
+++ b/ArcFormats/ArcAMI.cs
@@ -33,7 +33,7 @@ using System.Globalization;
 using System.Windows;
 using System.Windows.Media;
 using System.Windows.Media.Imaging;
-using ZLibNet;
+using GameRes.Compression;
 using GameRes.Formats.Strings;
 using GameRes.Formats.Properties;
 
@@ -303,6 +303,7 @@ namespace GameRes.Formats
                 throw new FileFormatException ("GRP image encoder not available");
             bool is_grp = grp.Signature == FormatCatalog.ReadSignature (input);
             input.Position = 0;
+            var start = output.Position;
             using (var zstream = new ZLibStream (output, CompressionMode.Compress, CompressionLevel.Level9, true))
             {
                 if (is_grp)
@@ -317,9 +318,8 @@ namespace GameRes.Formats
                     grp.Write (zstream, image);
                     entry.UnpackedSize = (uint)zstream.TotalIn;
                 }
-                zstream.Flush();
-                return (uint)zstream.TotalOut;
             }
+            return (uint)(output.Position - start);
         }
 
         public override ResourceOptions GetDefaultOptions ()
diff --git a/ArcFormats/ArcAZSys.cs b/ArcFormats/ArcAZSys.cs
index 753fa651..a8076eba 100644
--- a/ArcFormats/ArcAZSys.cs
+++ b/ArcFormats/ArcAZSys.cs
@@ -27,9 +27,9 @@ using System;
 using System.Collections.Generic;
 using System.ComponentModel.Composition;
 using System.IO;
+using GameRes.Compression;
 using GameRes.Formats.Strings;
 using GameRes.Utility;
-using ZLibNet;
 
 namespace GameRes.Formats.AZSys
 {
diff --git a/ArcFormats/ArcCCT.cs b/ArcFormats/ArcCCT.cs
index b53fa2bd..7bb226f7 100644
--- a/ArcFormats/ArcCCT.cs
+++ b/ArcFormats/ArcCCT.cs
@@ -29,8 +29,8 @@ using System.ComponentModel.Composition;
 using System.IO;
 using System.Linq;
 using System.Text;
+using GameRes.Compression;
 using GameRes.Utility;
-using ZLibNet;
 
 namespace GameRes.Formats.Selen
 {
diff --git a/ArcFormats/ArcFormats.csproj b/ArcFormats/ArcFormats.csproj
index a1280158..9f491937 100644
--- a/ArcFormats/ArcFormats.csproj
+++ b/ArcFormats/ArcFormats.csproj
@@ -51,6 +51,7 @@
     <Reference Include="System" />
     <Reference Include="System.ComponentModel.Composition" />
     <Reference Include="System.Core" />
+    <Reference Include="System.IO.Compression" />
     <Reference Include="System.Xaml" />
     <Reference Include="System.Xml.Linq" />
     <Reference Include="System.Data.DataSetExtensions" />
@@ -58,10 +59,6 @@
     <Reference Include="System.Data" />
     <Reference Include="System.Xml" />
     <Reference Include="WindowsBase" />
-    <Reference Include="zlibnet, Version=1.3.0.0, Culture=neutral, processorArchitecture=MSIL">
-      <SpecificVersion>False</SpecificVersion>
-      <HintPath>..\zlib\zlibnet.dll</HintPath>
-    </Reference>
   </ItemGroup>
   <ItemGroup>
     <Compile Include="ArcADPACK.cs" />
@@ -125,6 +122,7 @@
     <Compile Include="ArcRPA.cs" />
     <Compile Include="ArcS25.cs" />
     <Compile Include="ArcSAF.cs" />
+    <Compile Include="ZLibStream.cs" />
     <None Include="ArcSeraph.cs" />
     <Compile Include="ArcSPack.cs" />
     <Compile Include="ArcSteinsGate.cs" />
@@ -290,14 +288,6 @@
     </ProjectReference>
   </ItemGroup>
   <ItemGroup>
-    <Content Include="..\zlib\zlib32.dll">
-      <Link>zlib32.dll</Link>
-      <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
-    </Content>
-    <Content Include="..\zlib\zlib64.dll">
-      <Link>zlib64.dll</Link>
-      <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
-    </Content>
     <EmbeddedResource Include="Resources\ShiinaRio4.jpg" />
     <EmbeddedResource Include="Resources\ShiinaRio1.png" />
     <EmbeddedResource Include="Resources\ShiinaRio2.png" />
diff --git a/ArcFormats/ArcNPA.cs b/ArcFormats/ArcNPA.cs
index 92b5bc11..39a3c4d1 100644
--- a/ArcFormats/ArcNPA.cs
+++ b/ArcFormats/ArcNPA.cs
@@ -31,7 +31,7 @@ using System.ComponentModel.Composition;
 using System.Collections.Generic;
 using System.Diagnostics;
 using System.Runtime.InteropServices;
-using ZLibNet;
+using GameRes.Compression;
 using GameRes.Formats.Strings;
 using GameRes.Formats.Properties;
 
@@ -200,13 +200,13 @@ namespace GameRes.Formats.NitroPlus
                     {
                         if (entry.IsPacked)
                         {
+                            var start = destination.Position;
                             using (var zstream = new ZLibStream (destination, CompressionMode.Compress,
                                                                 CompressionLevel.Level9, true))
                             {
                                 file.CopyTo (zstream);
-                                zstream.Flush();
-                                entry.Size = (uint)zstream.TotalOut;
                             }
+                            entry.Size = (uint)(destination.Position - start);
                         }
                         else
                         {
diff --git a/ArcFormats/ArcNexas.cs b/ArcFormats/ArcNexas.cs
index 1e877d10..be9588ed 100644
--- a/ArcFormats/ArcNexas.cs
+++ b/ArcFormats/ArcNexas.cs
@@ -32,7 +32,6 @@ using System.ComponentModel.Composition;
 using GameRes.Compression;
 using GameRes.Formats.Strings;
 using GameRes.Utility;
-using ZLibNet;
 
 namespace GameRes.Formats.NeXAS
 {
diff --git a/ArcFormats/ArcNitro.cs b/ArcFormats/ArcNitro.cs
index ccf17a43..eb883cdd 100644
--- a/ArcFormats/ArcNitro.cs
+++ b/ArcFormats/ArcNitro.cs
@@ -28,8 +28,8 @@ using System.Collections.Generic;
 using System.ComponentModel.Composition;
 using System.IO;
 using System.Text;
+using GameRes.Compression;
 using GameRes.Utility;
-using ZLibNet;
 
 namespace GameRes.Formats.NitroPlus
 {
diff --git a/ArcFormats/ArcRPA.cs b/ArcFormats/ArcRPA.cs
index 8ebfa4fe..641a55b5 100644
--- a/ArcFormats/ArcRPA.cs
+++ b/ArcFormats/ArcRPA.cs
@@ -31,9 +31,9 @@ using System.Diagnostics;
 using System.Globalization;
 using System.IO;
 using System.Text;
+using GameRes.Compression;
 using GameRes.Formats.Properties;
 using GameRes.Formats.Strings;
-using ZLibNet;
 
 namespace GameRes.Formats.RenPy
 {
diff --git a/ArcFormats/ArcSAF.cs b/ArcFormats/ArcSAF.cs
index b928198d..750d4be8 100644
--- a/ArcFormats/ArcSAF.cs
+++ b/ArcFormats/ArcSAF.cs
@@ -27,8 +27,8 @@ using System;
 using System.Collections.Generic;
 using System.ComponentModel.Composition;
 using System.IO;
+using GameRes.Compression;
 using GameRes.Utility;
-using ZLibNet;
 
 namespace GameRes.Formats.Lune
 {
diff --git a/ArcFormats/ArcSeraph.cs b/ArcFormats/ArcSeraph.cs
index ce8592b0..50865115 100644
--- a/ArcFormats/ArcSeraph.cs
+++ b/ArcFormats/ArcSeraph.cs
@@ -28,7 +28,7 @@ using System.Collections.Generic;
 using System.ComponentModel.Composition;
 using System.IO;
 using System.Text.RegularExpressions;
-using ZLibNet;
+using GameRes.Compression;
 
 namespace GameRes.Formats.Seraphim
 {
diff --git a/ArcFormats/ArcWARC.cs b/ArcFormats/ArcWARC.cs
index d29f903b..5b72dea3 100644
--- a/ArcFormats/ArcWARC.cs
+++ b/ArcFormats/ArcWARC.cs
@@ -31,10 +31,10 @@ using System.Linq;
 using System.Runtime.InteropServices;
 using System.Windows;
 using System.Windows.Media.Imaging;
+using GameRes.Compression;
 using GameRes.Formats.Properties;
 using GameRes.Formats.Strings;
 using GameRes.Utility;
-using ZLibNet;
 
 namespace GameRes.Formats.ShiinaRio // 椎名里緒
 {
@@ -97,7 +97,7 @@ namespace GameRes.Formats.ShiinaRio // 椎名里緒
             Stream index;
             if (version >= 170)
             {
-                if (0x78 != enc_index[8]) // FIXME: check if it looks like ZLib stream
+                if (0x78 != enc_index[8]) // check if it looks like ZLib stream
                     return null;
                 var zindex = new MemoryStream (enc_index, 8, (int)index_length-8);
                 index = new ZLibStream (zindex, CompressionMode.Decompress);
diff --git a/ArcFormats/ArcXP3.cs b/ArcFormats/ArcXP3.cs
index 3b3ee818..078ab60d 100644
--- a/ArcFormats/ArcXP3.cs
+++ b/ArcFormats/ArcXP3.cs
@@ -27,6 +27,7 @@ using System;
 using System.IO;
 using System.IO.MemoryMappedFiles;
 using System.Text;
+using System.Text.RegularExpressions;
 using System.Linq;
 using System.Collections.Generic;
 using System.ComponentModel.Composition;
@@ -34,8 +35,8 @@ using System.Runtime.InteropServices;
 using System.Windows.Media;
 using System.Windows.Media.Imaging;
 using System.Diagnostics;
+using GameRes.Compression;
 using GameRes.Utility;
-using ZLibNet;
 using GameRes.Formats.Strings;
 using GameRes.Formats.Properties;
 
@@ -174,7 +175,7 @@ namespace GameRes.Formats.KiriKiri
                                 entry.IsEncrypted = 0 != header.ReadUInt32();
                                 long file_size = header.ReadInt64();
                                 long packed_size = header.ReadInt64();
-                                if (file_size > uint.MaxValue || packed_size > uint.MaxValue)
+                                if (file_size > uint.MaxValue || packed_size > uint.MaxValue || packed_size > file.MaxOffset)
                                 {
                                     goto NextEntry;
                                 }
@@ -193,7 +194,7 @@ namespace GameRes.Formats.KiriKiri
                                     entry.Cipher = NoCryptAlgorithm;
 
                                 char[] name = header.ReadChars (name_size);
-                                entry.Name = new string (name);
+                                entry.Name = NormalizePath (new string (name));
                                 entry.Type = FormatCatalog.Instance.GetTypeFromName (entry.Name);
                                 break;
                             }
@@ -246,6 +247,13 @@ NextEntry:
             return new ArcFile (file, this, dir);
         }
 
+        static readonly Regex PathRe = new Regex (@"[^\\/]+[\\/]\.\.[\\/]");
+
+        private static string NormalizePath (string filename)
+        {
+            return PathRe.Replace (filename, "");
+        }
+
         private long SkipExeHeader (ArcView file)
         {
             long offset = 0x10;
@@ -507,13 +515,13 @@ NextEntry:
             };
             if (compress)
             {
+                var start = output.Position;
                 using (var zstream = new ZLibStream (output, CompressionMode.Compress, CompressionLevel.Level9, true))
                 {
                     xp3entry.Hash = CheckedCopy (file, zstream);
-                    zstream.Flush();
-                    segment.PackedSize = (uint)zstream.TotalOut;
-                    xp3entry.Size = segment.PackedSize;
                 }
+                segment.PackedSize = (uint)(output.Position - start);
+                xp3entry.Size = segment.PackedSize;
             }
             else
             {
@@ -542,11 +550,9 @@ NextEntry:
                         PackedSize   = unpacked_size,
                     };
                     xp3entry.Segments.Add (segment);
-                    bool need_output_dispose = false;
                     if (compress)
                     {
                         output = new ZLibStream (output, CompressionMode.Compress, CompressionLevel.Level9, true);
-                        need_output_dispose = true;
                     }
                     unsafe
                     {
@@ -573,18 +579,17 @@ NextEntry:
                             }
                             if (hash_after_crypt)
                                 xp3entry.Hash = checksum.Value;
-                            if (compress)
-                            {
-                                output.Flush();
-                                segment.PackedSize = (uint)(output as ZLibStream).TotalOut;
-                                xp3entry.Size = segment.PackedSize;
-                            }
                         }
                         finally
                         {
                             view.SafeMemoryMappedViewHandle.ReleasePointer();
-                            if (need_output_dispose)
+                            if (compress)
+                            {
+                                var dest = (output as ZLibStream).BaseStream;
                                 output.Dispose();
+                                segment.PackedSize = (uint)(dest.Position - segment.Offset);
+                                xp3entry.Size = segment.PackedSize;
+                            }
                         }
                     }
                 }
diff --git a/ArcFormats/ArcYPF.cs b/ArcFormats/ArcYPF.cs
index efcfd011..cff26c65 100644
--- a/ArcFormats/ArcYPF.cs
+++ b/ArcFormats/ArcYPF.cs
@@ -30,7 +30,7 @@ using System.Collections.Generic;
 using System.ComponentModel.Composition;
 using System.Windows.Media;
 using System.Windows.Media.Imaging;
-using ZLibNet;
+using GameRes.Compression;
 using GameRes.Formats.Strings;
 using GameRes.Formats.Properties;
 using GameRes.Utility;
@@ -184,13 +184,13 @@ namespace GameRes.Formats.YuRis
                     {
                         if (entry.IsPacked)
                         {
+                            var start = output.Position;
                             using (var zstream = new ZLibStream (checked_stream, CompressionMode.Compress,
                                                                  CompressionLevel.Level9, true))
                             {
                                 input.CopyTo (zstream);
-                                zstream.Flush();
-                                entry.Size = (uint)zstream.TotalOut;
                             }
+                            entry.Size = (uint)(output.Position - start);
                         }
                         else
                         {
diff --git a/ArcFormats/AudioPCM.cs b/ArcFormats/AudioPCM.cs
index 1a2743b8..154066b4 100644
--- a/ArcFormats/AudioPCM.cs
+++ b/ArcFormats/AudioPCM.cs
@@ -26,8 +26,8 @@
 using System;
 using System.ComponentModel.Composition;
 using System.IO;
+using GameRes.Compression;
 using GameRes.Utility;
-using ZLibNet;
 
 namespace GameRes.Formats.Circus
 {
diff --git a/ArcFormats/AudioPMW.cs b/ArcFormats/AudioPMW.cs
index f0dda172..16612265 100644
--- a/ArcFormats/AudioPMW.cs
+++ b/ArcFormats/AudioPMW.cs
@@ -25,7 +25,7 @@
 
 using System.ComponentModel.Composition;
 using System.IO;
-using ZLibNet;
+using GameRes.Compression;
 
 namespace GameRes.Formats.ScenePlayer
 {
diff --git a/ArcFormats/ImageBMZ.cs b/ArcFormats/ImageBMZ.cs
index f04d4f78..d5b69715 100644
--- a/ArcFormats/ImageBMZ.cs
+++ b/ArcFormats/ImageBMZ.cs
@@ -27,7 +27,7 @@ using System.ComponentModel.Composition;
 using System.IO;
 using System.Text;
 using GameRes.Utility;
-using ZLibNet;
+using GameRes.Compression;
 
 namespace GameRes.Formats.BlackRainbow
 {
diff --git a/ArcFormats/ImageCPB.cs b/ArcFormats/ImageCPB.cs
index 7f970484..35c7d327 100644
--- a/ArcFormats/ImageCPB.cs
+++ b/ArcFormats/ImageCPB.cs
@@ -29,7 +29,7 @@ using System.IO;
 using System.Windows;
 using System.Windows.Media;
 using System.Windows.Media.Imaging;
-using ZLibNet;
+using GameRes.Compression;
 
 namespace GameRes.Formats.AZSys
 {
diff --git a/ArcFormats/ImageHG3.cs b/ArcFormats/ImageHG3.cs
index c01d2255..6b201540 100644
--- a/ArcFormats/ImageHG3.cs
+++ b/ArcFormats/ImageHG3.cs
@@ -28,7 +28,7 @@ using System.IO;
 using System.ComponentModel.Composition;
 using System.Windows.Media.Imaging;
 using System.Windows.Media;
-using ZLibNet;
+using GameRes.Compression;
 using GameRes.Utility;
 
 namespace GameRes.Formats
diff --git a/ArcFormats/ImagePMP.cs b/ArcFormats/ImagePMP.cs
index daea6d9e..870d3f42 100644
--- a/ArcFormats/ImagePMP.cs
+++ b/ArcFormats/ImagePMP.cs
@@ -26,8 +26,8 @@
 using System.ComponentModel.Composition;
 using System.IO;
 using System.Text;
+using GameRes.Compression;
 using GameRes.Utility;
-using ZLibNet;
 
 namespace GameRes.Formats.ScenePlayer
 {
@@ -50,10 +50,6 @@ namespace GameRes.Formats.ScenePlayer
             int first = stream.ReadByte() ^ 0x21;
             if (first != 0x78) // doesn't look like zlib stream
                 return null;
-            int flg = stream.ReadByte() ^ 0x21;
-            int fcheck = first << 8 | flg;
-            if (fcheck % 0x1f != 0)
-                return null;
 
             stream.Position = 0;
             using (var input = new XoredStream (stream, 0x21, true))
diff --git a/ArcFormats/ImageQNT.cs b/ArcFormats/ImageQNT.cs
index e8ff7c17..5da97bb9 100644
--- a/ArcFormats/ImageQNT.cs
+++ b/ArcFormats/ImageQNT.cs
@@ -29,8 +29,8 @@ using System.IO;
 using System.Windows;
 using System.Windows.Media;
 using System.Windows.Media.Imaging;
+using GameRes.Compression;
 using GameRes.Utility;
-using ZLibNet;
 
 namespace GameRes.Formats.AliceSoft
 {
diff --git a/inflate.cs b/inflate.cs
index 3c717c8a..3e847158 100644
--- a/inflate.cs
+++ b/inflate.cs
@@ -5,7 +5,7 @@
 
 using System;
 using System.IO;
-using ZLibNet;
+using System.IO.Compression;
 
 class Inflate
 {
@@ -16,10 +16,10 @@ class Inflate
         try
         {
             var input = File.Open (args[0], FileMode.Open, FileAccess.Read);
-//            input.Position = 2;
-            using (var stream = new ZLibStream (input, CompressionMode.Decompress))
-                using (var output = File.Create (args[1]))
-                    stream.CopyTo (output);
+            input.Position = 2;
+            using (var stream = new DeflateStream (input, CompressionMode.Decompress))
+            using (var output = File.Create (args[1]))
+                stream.CopyTo (output);
             Console.WriteLine ("{0} => {1}", args[0], args[1]);
         }
         catch (Exception X)