From fd8599c4ba40af9be56cc5230d6d0b1ff4590be4 Mon Sep 17 00:00:00 2001
From: morkt <morkt@users.noreply.github.com>
Date: Thu, 25 Oct 2018 17:01:29 +0400
Subject: [PATCH] (Legacy): added GAM images.

---
 Legacy/Legacy.csproj          |   2 +
 Legacy/ProjectMyu/ImageGAM.cs | 123 ++++++++++++++++++++++++++++++++++
 2 files changed, 125 insertions(+)
 create mode 100644 Legacy/ProjectMyu/ImageGAM.cs

diff --git a/Legacy/Legacy.csproj b/Legacy/Legacy.csproj
index 71ac7cae..000e3b82 100644
--- a/Legacy/Legacy.csproj
+++ b/Legacy/Legacy.csproj
@@ -88,6 +88,8 @@
     <Compile Include="Lazycrew\ImageDAT.cs" />
     <Compile Include="Melonpan\ArcTTD.cs" />
     <Compile Include="Mmfass\ArcSDA.cs" />
+    <Compile Include="PenguinWorks\ArcPAC.cs" />
+    <Compile Include="ProjectMyu\ImageGAM.cs" />
     <Compile Include="RSystem\ArcRAD.cs" />
     <Compile Include="RSystem\ImageRSG.cs" />
     <Compile Include="Brownie\ArcNAF.cs" />
diff --git a/Legacy/ProjectMyu/ImageGAM.cs b/Legacy/ProjectMyu/ImageGAM.cs
new file mode 100644
index 00000000..a2e86da6
--- /dev/null
+++ b/Legacy/ProjectMyu/ImageGAM.cs
@@ -0,0 +1,123 @@
+//! \file       ImageGAM.cs
+//! \date       2018 Oct 23
+//! \brief      Project-μ image format.
+//
+// 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.Collections.Generic;
+using System.ComponentModel.Composition;
+using System.IO;
+using GameRes.Compression;
+
+namespace GameRes.Formats.ProjectMu
+{
+    [Export(typeof(ImageFormat))]
+    public class GamFormat : ImageFormat
+    {
+        public override string         Tag { get { return "GAM"; } }
+        public override string Description { get { return "Project-μ image format"; } }
+        public override uint     Signature { get { return 0x4D4147; } } // 'GAM'
+
+        public override ImageMetaData ReadMetaData (IBinaryStream file)
+        {
+            using (var input = OpenGamStream (file))
+                return Bmp.ReadMetaData (input);
+        }
+
+        public override ImageData Read (IBinaryStream file, ImageMetaData info)
+        {
+            using (var input = OpenGamStream (file))
+                return Bmp.Read (input, info);
+        }
+
+        IBinaryStream OpenGamStream (IBinaryStream input)
+        {
+            input.Position = 8;
+            var unpacked = new PackedStream<GamDecompressor> (input.AsStream, true);
+            return new BinaryStream (unpacked, input.Name);
+        }
+
+        public override void Write (Stream file, ImageData image)
+        {
+            throw new System.NotImplementedException ("GamFormat.Write not implemented");
+        }
+    }
+
+    internal class GamDecompressor : Decompressor
+    {
+        Stream      m_input;
+
+        public override void Initialize (Stream input)
+        {
+            m_input = input;
+        }
+
+        protected override IEnumerator<int> Unpack ()
+        {
+            var frame = new byte[0x100];
+            int frame_pos = 0;
+            int bits = 1;
+            for (;;)
+            {
+                if (1 == bits)
+                {
+                    int b = m_input.ReadByte();
+                    if (-1 == b)
+                        yield break;
+                    bits = b;
+                    b = m_input.ReadByte();
+                    if (-1 == b)
+                        yield break;
+                    bits |= b << 8 | 0x10000;
+                }
+                if (0 == (bits & 1))
+                {
+                    int b = m_input.ReadByte();
+                    if (-1 == b)
+                        yield break;
+                    frame[frame_pos++ & 0xFF] = (byte)b;
+                    m_buffer[m_pos++] = (byte)b;
+                    if (0 == --m_length)
+                        yield return m_pos;
+                }
+                else
+                {
+                    int offset = m_input.ReadByte();
+                    if (-1 == offset)
+                        yield break;
+                    int count = m_input.ReadByte();
+                    if (-1 == count)
+                        yield break;
+                    while (count --> 0)
+                    {
+                        byte v = frame[(frame_pos - offset) & 0xFF];
+                        frame[frame_pos++ & 0xFF] = v;
+                        m_buffer[m_pos++] = v;
+                        if (0 == --m_length)
+                            yield return m_pos;
+                    }
+                }
+                bits >>= 1;
+            }
+        }
+    }
+}