From 6c6f5d927dedf95499aa03a90873c2cb8e4f2720 Mon Sep 17 00:00:00 2001
From: morkt <morkt@users.noreply.github.com>
Date: Thu, 14 Jun 2018 23:17:34 +0400
Subject: [PATCH] implemented BELL-DA compressed bitmaps.

---
 ArcFormats/BellDa/ImageCP.cs | 127 +++++++++++++++++++++++++++++++++++
 1 file changed, 127 insertions(+)
 create mode 100644 ArcFormats/BellDa/ImageCP.cs

diff --git a/ArcFormats/BellDa/ImageCP.cs b/ArcFormats/BellDa/ImageCP.cs
new file mode 100644
index 00000000..1019acf8
--- /dev/null
+++ b/ArcFormats/BellDa/ImageCP.cs
@@ -0,0 +1,127 @@
+//! \file       ImageCP.cs
+//! \date       2018 Jun 11
+//! \brief      BELL-DA LZSS-compressed bitmap.
+//
+// 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.BellDa
+{
+    [Export(typeof(ImageFormat))]
+    public class CpFormat : ImageFormat
+    {
+        public override string         Tag { get { return "BMP/CP"; } }
+        public override string Description { get { return "BELL-DA compressed bitmap"; } }
+        public override uint     Signature { get { return 0; } }
+
+        public CpFormat ()
+        {
+            Signatures = new uint[] { 0x42FD5043, 0 };
+        }
+
+        public override ImageMetaData ReadMetaData (IBinaryStream file)
+        {
+            var header = file.ReadHeader (5);
+            if (!header.AsciiEqual (0, "CP") || (header[2] & 0xC0) != 0xC0 ||
+                !header.AsciiEqual (3, "BM"))
+                return null;
+            using (var bmp = OpenCompressed (file))
+                return Bmp.ReadMetaData (bmp);
+        }
+
+        public override ImageData Read (IBinaryStream file, ImageMetaData info)
+        {
+            using (var bmp = OpenCompressed (file))
+                return Bmp.Read (bmp, info);
+        }
+
+        internal IBinaryStream OpenCompressed (IBinaryStream file)
+        {
+            Stream input = new StreamRegion (file.AsStream, 2, true);
+            input = new PackedStream<CpLzssDecompressor> (input);
+            return new BinaryStream (input, file.Name);
+        }
+
+        public override void Write (Stream file, ImageData image)
+        {
+            throw new System.NotImplementedException ("CpFormat.Write not implemented");
+        }
+    }
+
+    internal class CpLzssDecompressor : Decompressor
+    {
+        Stream          m_input;
+
+        public override void Initialize (Stream input)
+        {
+            m_input = input;
+        }
+
+        protected override IEnumerator<int> Unpack ()
+        {
+            byte[] frame = new byte[0x1000];
+            int frame_pos = 1;
+            const int frame_mask = 0xFFF;
+            for (;;)
+            {
+                int ctl = m_input.ReadByte();
+                if (-1 == ctl)
+                    yield break;
+                for (int bit = 0x80; bit != 0; bit >>= 1)
+                {
+                    if (0 != (ctl & bit))
+                    {
+                        int b = m_input.ReadByte();
+                        if (-1 == b)
+                            yield break;
+                        frame[frame_pos++ & frame_mask] = (byte)b;
+                        m_buffer[m_pos++] = (byte)b;
+                        if (0 == --m_length)
+                            yield return m_pos;
+                    }
+                    else
+                    {
+                        int hi = m_input.ReadByte();
+                        if (-1 ==hi)
+                            yield break;
+                        int lo = m_input.ReadByte();
+                        if (-1 == lo)
+                            yield break;
+                        int offset = hi << 4 | lo >> 4;
+                        for (int count = 2 + (lo & 0xF); count > 0; --count)
+                        {
+                            byte v = frame[offset++ & frame_mask];
+                            frame[frame_pos++ & frame_mask] = v;
+                            m_buffer[m_pos++] = v;
+                            if (0 == --m_length)
+                                yield return m_pos;
+                        }
+                    }
+                }
+            }
+        }
+    }
+}