From d29691e0ee18356e0902244f85031ce8cdd90668 Mon Sep 17 00:00:00 2001
From: Valeriy Mironov <valeronm@gmail.com>
Date: Sun, 13 May 2018 08:21:37 +0300
Subject: [PATCH] Started work on Cor .res decompression

---
 Resources/Compression.cs   | 88 ++++++++++++++++++++++++++++++++++++++
 Resources/Resources.csproj |  1 +
 WatchFace/Program.cs       |  6 ++-
 3 files changed, 94 insertions(+), 1 deletion(-)
 create mode 100644 Resources/Compression.cs

diff --git a/Resources/Compression.cs b/Resources/Compression.cs
new file mode 100644
index 0000000..02faa20
--- /dev/null
+++ b/Resources/Compression.cs
@@ -0,0 +1,88 @@
+using NLog;
+using System;
+using System.IO;
+
+namespace Resources
+{
+    public class Compression
+    {
+        private static readonly Logger Logger = LogManager.GetCurrentClassLogger();
+
+        class Header
+        {
+            public const int Size = 9;
+
+            public byte[] Buffer;
+            public byte Flags => Buffer[0];
+            public uint CompressedLength => BitConverter.ToUInt32(Buffer, 1);
+            public uint DecompressedLength => BitConverter.ToUInt32(Buffer, 5);
+            public bool IsCompressed => (Flags & 1) > 0;
+            public int LengthSize => (Flags & 2) > 0 ? 4 : 1;
+
+            public static Header Read(BinaryReader reader)
+            {
+                var buffer = new byte[Size];
+                reader.Read(buffer, 0, buffer.Length);
+                return new Header { Buffer = buffer };
+            }
+        }
+
+        private readonly Stream _stream;
+        private readonly BinaryReader _reader;
+        private readonly long _streamSize;
+
+        public Compression(Stream stream)
+        {
+            _stream = stream;
+            _reader = new BinaryReader(stream);
+            _streamSize = stream.Length;
+        }
+
+        public Stream Decompress()
+        {
+            var output = new MemoryStream();
+            var buffer = new byte[5120];
+
+            var offset = (uint)0;
+
+            while (true)
+            {
+                var header = Header.Read(_reader);
+
+                if (header.DecompressedLength == 4096)
+                {
+                    Logger.Debug("Compression block header read at offset 0x{0:X}", offset);
+                    Logger.Debug("Flags 0x{0:X}, Compressed {1}, Decompressed {2}, LengthSize {3}",
+                        header.Flags, header.CompressedLength, header.DecompressedLength, header.LengthSize);
+
+                    _reader.Read(buffer, 0, (int)header.CompressedLength - 9);
+                    offset += header.CompressedLength;
+
+
+                    if (header.IsCompressed)
+                    {
+                        // Here should be decompression
+
+                    }
+                    else
+                        output.Write(buffer, 0, (int)header.CompressedLength);
+                }
+                else
+                {
+                    var latestBlock = _streamSize - offset;
+                    Logger.Debug("Latest block read at offset 0x{0:X}, size: {1}", offset, latestBlock);
+
+                    _reader.Read(buffer, 0, (int)(latestBlock - Header.Size));
+
+                    output.Write(header.Buffer, 0, Header.Size);
+                    output.Write(buffer, 0, (int)(latestBlock - Header.Size));
+                    break;
+                }
+            }
+
+            output.Seek(0, SeekOrigin.Begin);
+            return output;
+        }
+
+    }
+}
diff --git a/Resources/Resources.csproj b/Resources/Resources.csproj
index bc6ff7d..8d09397 100644
--- a/Resources/Resources.csproj
+++ b/Resources/Resources.csproj
@@ -48,6 +48,7 @@
     <Reference Include="System.Xml" />
   </ItemGroup>
   <ItemGroup>
+    <Compile Include="Compression.cs" />
     <Compile Include="Extractor.cs" />
     <Compile Include="ImageLoader.cs" />
     <Compile Include="Image\ImageType.cs" />
diff --git a/WatchFace/Program.cs b/WatchFace/Program.cs
index 1847788..024530e 100644
--- a/WatchFace/Program.cs
+++ b/WatchFace/Program.cs
@@ -72,6 +72,9 @@ namespace WatchFace
                         case ".bin":
                             UnpackWatchFace(inputFileName);
                             break;
+                        case ".res":
+                            UnpackResources(inputFileName);
+                            break;
                         case ".json":
                             PackWatchFace(inputFileName);
                             break;
@@ -205,7 +208,8 @@ namespace WatchFace
             FileDescriptor resDescriptor;
             using (var stream = File.OpenRead(inputFileName))
             {
-                resDescriptor = FileReader.Read(stream);
+                var decompressedStream = new Compression(stream).Decompress();
+                resDescriptor = FileReader.Read(decompressedStream);
             }
 
             ExportResConfig(resDescriptor, Path.Combine(outputDirectory, "header.json"));