introduced multi-file archive class.

ArcFormats/ArcFormats.csproj

@@ -186,6 +186,7 @@
     <Compile Include="Maika\AudioWV5.cs" />
     <Compile Include="MangaGamer\ArcSHA.cs" />
     <Compile Include="Mnp\ArcMMA.cs" />
+    <Compile Include="MultiFileArchive.cs" />
     <Compile Include="Noesis\ArcIGA.cs" />
     <Compile Include="NonColor\ArcMinato.cs" />
     <Compile Include="Misc\ArcBIN.cs" />

ArcFormats/MultiFileArchive.cs

@@ -0,0 +1,110 @@
+//! \file       MultiFileArchive.cs
+//! \date       2018 Aug 09
+//! \brief      Treat multiple files as a single archive by virtually concatenating them.
+//
+// Copyright (C) 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
+// deal in the Software without restriction, including without limitation the
+// rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
+// sell copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in
+// all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+// IN THE SOFTWARE.
+//
+
+using System;
+using System.Collections.Generic;
+using System.IO;
+
+namespace GameRes.Formats
+{
+    public class MultiFileArchive : ArcFile
+    {
+        IEnumerable<ArcView>  m_parts;
+
+        public IEnumerable<ArcView> Parts
+        {
+            get
+            {
+                yield return File;
+                if (m_parts != null)
+                    foreach (var part in m_parts)
+                        yield return part;
+            }
+        }
+
+        public MultiFileArchive (ArcView arc, ArchiveFormat impl, ICollection<Entry> dir, IEnumerable<ArcView> parts = null)
+            : base (arc, impl, dir)
+        {
+            m_parts = parts;
+        }
+
+        public Stream OpenStream (Entry entry)
+        {
+            Stream input = null;
+            try
+            {
+                long part_offset = 0;
+                long entry_start = entry.Offset;
+                long entry_end   = entry.Offset + GetEntrySize (entry);
+                foreach (var part in Parts)
+                {
+                    long part_end_offset = part_offset + part.MaxOffset;
+                    if (entry_start < part_end_offset)
+                    {
+                        uint part_size = (uint)Math.Min (entry_end - entry_start, part_end_offset - entry_start);
+                        var entry_part = part.CreateStream (entry_start - part_offset, part_size);
+                        if (input != null)
+                            input = new ConcatStream (input, entry_part);
+                        else
+                            input = entry_part;
+                        entry_start += part_size;
+                        if (entry_start >= entry_end)
+                            break;
+                    }
+                    part_offset = part_end_offset;
+                }
+                if (null == input)
+                    return Stream.Null;
+                return input;
+            }
+            catch
+            {
+                if (input != null)
+                    input.Dispose();
+                throw;
+            }
+        }
+
+        protected virtual uint GetEntrySize (Entry entry)
+        {
+            return entry.Size;
+        }
+        
+        bool m_disposed = false;
+        protected override void Dispose (bool disposing)
+        {
+            if (m_disposed)
+                return;
+
+            if (disposing && m_parts != null)
+            {
+                foreach (var arc in m_parts)
+                    arc.Dispose();
+            }
+            m_disposed = true;
+            base.Dispose (disposing);
+        }
+    }
+}