(Entis): improved ErisaN compression handling.

ArcFormats/Entis/ArcNOA.cs

@@ -2,7 +2,7 @@
 //! \date       Thu Apr 23 15:57:17 2015
 //! \brief      Entis GLS engine archives implementation.
 //
-// Copyright (C) 2015-2016 by morkt
+// Copyright (C) 2015-2018 by morkt
 //
 // Permission is hereby granted, free of charge, to any person obtaining a copy
 // of this software and associated documentation files (the "Software"), to
@@ -77,7 +77,7 @@ namespace GameRes.Formats.Entis
 
         public NoaOpener ()
         {
-            Extensions = new string[] { "noa", "dat", "rsa" };
+            Extensions = new string[] { "noa", "dat", "rsa", "arc" };
             Settings = new[] { NoaEncoding };
         }
 
@@ -96,14 +96,14 @@ namespace GameRes.Formats.Entis
             var reader = new IndexReader (file, NoaEncoding.Get<Encoding>());
             if (!reader.ParseRoot() || 0 == reader.Dir.Count)
                 return null;
-            if (!reader.HasEncrypted)
+            if (reader.HasEncrypted)
-                return new ArcFile (file, this, reader.Dir);
+            {
-
                 var password = GetArcPassword (file.Name);
-            if (string.IsNullOrEmpty (password))
+                if (!string.IsNullOrEmpty (password))
-                return new ArcFile (file, this, reader.Dir);
                     return new NoaArchive (file, this, reader.Dir, password);
             }
+            return new ArcFile (file, this, reader.Dir);
+        }
 
         public override Stream OpenEntry (ArcFile arc, Entry entry)
         {
@@ -118,8 +118,8 @@ namespace GameRes.Formats.Entis
 
             if (EncType.ERISACode == nent.Encryption)
             {
-                using (var enc = arc.File.CreateStream (entry.Offset+0x10, (uint)size-4))
+                var enc = arc.File.CreateStream (entry.Offset+0x10, (uint)size-4);
-                    return DecodeNemesis (enc);
+                return new ErisaNemesisStream (enc, (int)entry.Size);
             }
 
             var narc = arc as NoaArchive;
@@ -183,7 +183,7 @@ namespace GameRes.Formats.Entis
                         if (null == cotomi)
                             continue;
                         using (var res = new MemoryStream (cotomi))
-                        using (var input = DecodeNemesis (res))
+                        using (var input = new ErisaNemesisStream (res))
                         {
                             var xml = new XmlDocument();
                             xml.Load (input);
@@ -210,24 +210,6 @@ namespace GameRes.Formats.Entis
             return null;
         }
 
-        Stream DecodeNemesis (Stream input)
-        {
-            var decoder = new NemesisDecodeContext();
-            decoder.AttachInputFile (input);
-            decoder.PrepareToDecodeERISANCode();
-            var file = new MemoryStream ((int)input.Length);
-            var buffer = new byte[0x10000];
-            for (;;)
-            {
-                int read = (int)decoder.DecodeNemesisCodeBytes (buffer, 0x10000);
-                if (0 == read)
-                    break;
-                file.Write (buffer, 0, read);
-            }
-            file.Position = 0;
-            return file;
-        }
-
         Stream DecodeBSHF (Stream input, string password)
         {
             uint nTotalBytes = (uint)input.Length - 4;
@@ -317,10 +299,11 @@ namespace GameRes.Formats.Entis
 
                     entry.Encryption = m_file.View.ReadUInt32 (dir_offset);
                     m_found_encrypted = m_found_encrypted || (EncType.Raw != entry.Encryption && EncType.ERISACode != entry.Encryption);
+                    bool is_packed = EncType.ERISACode == entry.Encryption;
                     dir_offset += 4;
 
                     entry.Offset = base_offset + m_file.View.ReadInt64 (dir_offset);
-                    if (!entry.CheckPlacement (m_file.MaxOffset))
+                    if (!is_packed && !entry.CheckPlacement (m_file.MaxOffset))
                     {
                         entry.Size = (uint)(m_file.MaxOffset - entry.Offset);
                     }

ArcFormats/Entis/ErisaNemesis.cs

@@ -5,6 +5,7 @@
 
 using System;
 using System.Diagnostics;
+using System.IO;
 
 namespace GameRes.Formats.Entis
 {
@@ -64,17 +65,16 @@ namespace GameRes.Formats.Entis
 
         public override uint DecodeBytes (Array ptrDst, uint nCount)
         {
-            return DecodeNemesisCodeBytes (ptrDst as byte[], nCount);
+            return DecodeNemesisCodeBytes (ptrDst as byte[], 0, nCount);
         }
 
-        public uint DecodeNemesisCodeBytes (byte[] ptrDst, uint nCount)
+        public uint DecodeNemesisCodeBytes (byte[] ptrDst, int dst, uint nCount)
         {
             if (m_flagEOF)
                 return 0;
 
             ErisaProbBase pBase = m_pProbERISA;
             uint nDecoded = 0;
-            int dst = 0;
             byte bytSymbol;
             while (nDecoded < nCount)
             {
@@ -150,7 +150,6 @@ namespace GameRes.Formats.Entis
                         if (nSymbol != ErisaProbModel.EscCode)
                         {
                             pModel.AddSymbol ((short)nSymbol);
-                            iSym = -1;
                         }
                         else
                         {
@@ -214,7 +213,7 @@ namespace GameRes.Formats.Entis
 
                 if ((pBase.dwWorkUsed < ErisaProbBase.SlotMax) && (iDeg < 4))
                 {
-                    int iSymbol = ((byte)nSymbol) >> ErisaProbBase.m_nShiftCount[iDeg];
+                    int iSymbol = bytSymbol >> ErisaProbBase.m_nShiftCount[iDeg];
                     if (iSymbol >= ErisaProbModel.SubSortMax)
                         throw new InvalidFormatException ("Invalid Nemesis encoding sequence");
                     if (++pModel.SubModel[iSymbol].Occured >= ErisaProbBase.m_nNewProbLimit[iDeg])
@@ -295,4 +294,45 @@ namespace GameRes.Formats.Entis
         public uint     first;
         public uint[]   index = new uint[Nemesis.IndexLimit];
     }
+
+    internal class ErisaNemesisStream : InputProxyStream
+    {
+        NemesisDecodeContext    m_decoder;
+        int                     m_remaining;
+        bool                    m_eof = false;
+
+        public ErisaNemesisStream (Stream input, int output_length = 0) : base (input)
+        {
+            m_decoder = new NemesisDecodeContext();
+            m_decoder.AttachInputFile (input);
+            m_decoder.PrepareToDecodeERISANCode();
+            m_remaining = output_length > 0 ? output_length : int.MaxValue;
+        }
+
+        public override int Read (byte[] buffer, int offset, int count)
+        {
+            int read = 0;
+            if (!m_eof && m_remaining > 0)
+            {
+                uint chunk_size = (uint)Math.Min (count, m_remaining);
+                read = (int)m_decoder.DecodeNemesisCodeBytes (buffer, offset, chunk_size);
+                m_eof = read < count;
+                m_remaining -= read;
+            }
+            return read;
+        }
+
+        public override bool CanSeek  { get { return false; } }
+        public override long Length   { get { throw new NotSupportedException(); } }
+
+        public override long Position {
+            get { throw new NotSupportedException(); }
+            set { throw new NotSupportedException(); }
+        }
+
+        public override long Seek (long offset, SeekOrigin origin)
+        {
+            throw new NotSupportedException();
+        }
+    }
 }