implemented CPZ7 archives.

ArcFormats/Cmvs/HuffmanDecoder.cs

@@ -0,0 +1,108 @@
+//! \file       HuffmanDecoder.cs
+//! \date       2017 Nov 27
+//! \brief      Custom Huffman decoder for CPZ archives.
+//
+// Copyright (C) 2017 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.IO;
+using GameRes.Utility;
+
+namespace GameRes.Formats.Purple
+{
+    internal sealed class HuffmanDecoder
+    {
+        byte[]          m_input;
+        byte[]          m_output;
+
+        int             m_src;
+        int             m_bits;
+        int             m_bit_count;
+
+        ushort[] lhs = new ushort[512];
+        ushort[] rhs = new ushort[512];
+        ushort token = 256;
+
+        public HuffmanDecoder (byte[] src, int index, int length, byte[] dst)
+        {
+            m_input = src;
+            m_output = dst;
+
+            m_src = index;
+            m_bit_count = 0;
+        }
+
+        public byte[] Unpack ()
+        {
+            int dst = 0;
+            token = 256;
+            ushort root = CreateTree();
+            while (dst < m_output.Length)
+            {
+                ushort symbol = root;
+                while (symbol >= 0x100)
+                {
+                    if (0 != GetBits (1))
+                        symbol = rhs[symbol];
+                    else
+                        symbol = lhs[symbol];
+                }
+                m_output[dst++] = (byte)symbol;
+            }
+            return m_output;
+        }
+
+        ushort CreateTree()
+        {
+            if (0 != GetBits (1))
+            {
+                ushort v = token++;
+                if (v >= 511)
+                    throw new InvalidDataException ("Invalid compressed data");
+                lhs[v] =  CreateTree();
+                rhs[v] =  CreateTree();
+                return v;
+            }
+            else
+            {
+                return (ushort)GetBits (8);
+            }
+        }
+
+        int GetBits (int count)
+        {
+            int bits = 0;
+            while (count --> 0)
+            {
+                if (0 == m_bit_count)
+                {
+                    m_bits = LittleEndian.ToInt32 (m_input, m_src);
+                    m_src += 4;
+                    m_bit_count = 32;
+                }
+                bits = bits << 1 | (m_bits & 1);
+                m_bits >>= 1;
+                --m_bit_count;
+            }
+            return bits;
+        }
+    }
+}