diff --git a/ArcFormats/ArcFormats.csproj b/ArcFormats/ArcFormats.csproj
index 918d02c1..b1d078fa 100644
--- a/ArcFormats/ArcFormats.csproj
+++ b/ArcFormats/ArcFormats.csproj
@@ -104,6 +104,8 @@
+
+
diff --git a/ArcFormats/Cmvs/ArcCPZ.cs b/ArcFormats/Cmvs/ArcCPZ.cs
index 4f5f2c87..080a46b7 100644
--- a/ArcFormats/Cmvs/ArcCPZ.cs
+++ b/ArcFormats/Cmvs/ArcCPZ.cs
@@ -2,7 +2,7 @@
//! \date Tue Nov 24 11:27:23 2015
//! \brief Purple Software resource archive.
//
-// Copyright (C) 2015-2016 by morkt
+// Copyright (C) 2015-2017 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
@@ -29,7 +29,6 @@ using System.ComponentModel.Composition;
using System.IO;
using System.Linq;
using GameRes.Utility;
-using System.Security.Cryptography;
namespace GameRes.Formats.Purple
{
@@ -41,6 +40,7 @@ namespace GameRes.Formats.Purple
public Cmvs.Md5Variant Md5Variant;
public uint DecoderFactor;
public uint EntryInitKey;
+ public uint EntrySubKey = 0x5C29E87B;
public byte EntryTailKey;
public byte EntryKeyPos = 9;
public uint IndexSeed = 0x2A65CB4E;
@@ -57,17 +57,6 @@ namespace GameRes.Formats.Purple
public uint Key;
}
- internal class CpzHeader
- {
- public int DirCount;
- public int DirEntriesSize;
- public int FileEntriesSize;
- public uint[] CmvsMd5 = new uint[4];
- public uint MasterKey;
- public bool IsEncrypted;
- public uint EntryKey;
- }
-
internal class CpzArchive : ArcFile
{
public CpzHeader Header;
@@ -98,7 +87,7 @@ namespace GameRes.Formats.Purple
public CpzOpener ()
{
- Signatures = new uint[] { 0x355A5043, 0x365A5043 };
+ Signatures = new uint[] { 0x355A5043, 0x365A5043, 0x375A5043 };
}
public static Dictionary KnownSchemes = new Dictionary();
@@ -113,75 +102,40 @@ namespace GameRes.Formats.Purple
{
if (null == KnownSchemes)
throw new OperationCanceledException ("Outdated encryption schemes database");
- var header = file.View.ReadBytes (0, 0x3C);
- var checksum = file.View.ReadUInt32 (0x3C);
- if (checksum != CheckSum (header, 0, 0x3C, 0x923A564Cu))
- return null;
- int version = header[3] - '0';
- CpzHeader cpz = 5 == version ? ReadHeaderV5 (header) : ReadHeaderV6 (header);
- int index_size = cpz.DirEntriesSize + cpz.FileEntriesSize;
- var index = file.View.ReadBytes (0x40, (uint)index_size);
- if (index.Length != index_size)
+
+ var cpz = CpzHeader.Parse (file);
+ if (null == cpz)
return null;
- using (var md5 = MD5.Create())
+ var index = file.View.ReadBytes (cpz.IndexOffset, cpz.IndexSize);
+ if (!cpz.VerifyIndex (index))
+ return null;
+
+ int file_table_size = cpz.DirEntriesSize + cpz.FileEntriesSize;
+ if (cpz.IndexKeySize > 24)
{
- var hash = md5.ComputeHash (index);
- if (!header.Skip (0x10).Take (0x10).SequenceEqual (hash))
- return null;
+ var index_key = UnpackIndexKey (index, file_table_size, cpz.IndexKeySize);
+ for (int i = 0; i < file_table_size; ++i)
+ {
+ index[i] ^= index_key[(i + 3) % 0x3FF];
+ }
}
+
+ var index_copy = new CowArray (index, 0, file_table_size).ToArray();
var cmvs_md5 = cpz.CmvsMd5.Clone() as uint[];
- foreach (var scheme in KnownSchemes.Values.Where (s => s.Version == version))
+ foreach (var scheme in KnownSchemes.Values.Where (s => s.Version == cpz.Version))
{
var arc = ReadIndex (file, scheme, cpz, index);
if (null != arc)
return arc;
// both CmvsMd5 and index was altered by ReadIndex in decryption attempt
Array.Copy (cmvs_md5, cpz.CmvsMd5, 4);
- file.View.Read (0x40, index, 0, (uint)index_size);
+ Array.Copy (index, index_copy, file_table_size);
}
throw new UnknownEncryptionScheme();
}
- CpzHeader ReadHeaderV5 (byte[] header)
- {
- uint entry_key = 0x37ACF831 ^ LittleEndian.ToUInt32 (header, 0x38);
- var cpz = new CpzHeader
- {
- DirCount = -0x1C5AC27 ^ LittleEndian.ToInt32 (header, 4),
- DirEntriesSize = 0x37F298E7 ^ LittleEndian.ToInt32 (header, 8),
- FileEntriesSize = 0x7A6F3A2C ^ LittleEndian.ToInt32 (header, 0x0C),
- MasterKey = 0xAE7D39BF ^ LittleEndian.ToUInt32 (header, 0x30),
- IsEncrypted = 0 != (0xFB73A955 ^ LittleEndian.ToUInt32 (header, 0x34)),
- EntryKey = 0,
- };
- cpz.CmvsMd5[0] = 0x43DE7C19 ^ LittleEndian.ToUInt32 (header, 0x20);
- cpz.CmvsMd5[1] = 0xCC65F415 ^ LittleEndian.ToUInt32 (header, 0x24);
- cpz.CmvsMd5[2] = 0xD016A93C ^ LittleEndian.ToUInt32 (header, 0x28);
- cpz.CmvsMd5[3] = 0x97A3BA9A ^ LittleEndian.ToUInt32 (header, 0x2C);
- return cpz;
- }
-
- CpzHeader ReadHeaderV6 (byte[] header)
- {
- uint entry_key = 0x37ACF832 ^ LittleEndian.ToUInt32 (header, 0x38);
- var cpz = new CpzHeader
- {
- DirCount = -0x1C5AC26 ^ LittleEndian.ToInt32 (header, 4),
- DirEntriesSize = 0x37F298E8 ^ LittleEndian.ToInt32 (header, 8),
- FileEntriesSize = 0x7A6F3A2D ^ LittleEndian.ToInt32 (header, 0x0C),
- MasterKey = 0xAE7D39B7 ^ LittleEndian.ToUInt32 (header, 0x30),
- IsEncrypted = 0 != (0xFB73A956 ^ LittleEndian.ToUInt32 (header, 0x34)),
- EntryKey = 0x7DA8F173 * Binary.RotR (entry_key, 5) + 0x13712765,
- };
- cpz.CmvsMd5[0] = 0x43DE7C1A ^ LittleEndian.ToUInt32 (header, 0x20);
- cpz.CmvsMd5[1] = 0xCC65F416 ^ LittleEndian.ToUInt32 (header, 0x24);
- cpz.CmvsMd5[2] = 0xD016A93D ^ LittleEndian.ToUInt32 (header, 0x28);
- cpz.CmvsMd5[3] = 0x97A3BA9B ^ LittleEndian.ToUInt32 (header, 0x2C);
- return cpz;
- }
-
- ArcFile ReadIndex (ArcView file, CmvsScheme scheme, CpzHeader cpz, byte[] index)
+ internal ArcFile ReadIndex (ArcView file, CmvsScheme scheme, CpzHeader cpz, byte[] index)
{
var cmvs_md5 = Cmvs.MD5.Create (scheme.Md5Variant);
cmvs_md5.Compute (cpz.CmvsMd5);
@@ -200,7 +154,7 @@ namespace GameRes.Formats.Purple
DecryptIndexDirectory (index, cpz.DirEntriesSize, key);
decoder.Init (cpz.MasterKey, cpz.CmvsMd5[2]);
- int base_offset = 0x40 + index.Length;
+ uint base_offset = cpz.IndexOffset + cpz.IndexSize;
int dir_offset = 0;
var dir = new List();
for (int i = 0; i < cpz.DirCount; ++i)
@@ -239,16 +193,20 @@ namespace GameRes.Formats.Purple
for (int j = 0; j < file_count; ++j)
{
int entry_size = LittleEndian.ToInt32 (index, cur_offset);
- if (entry_size > index.Length || entry_size <= 0x18)
+ if (entry_size > index.Length || entry_size <= cpz.EntryNameOffset)
return null;
- var name = Binary.GetCString (index, cur_offset+0x18, cur_entries_end-(cur_offset+0x18));
+ int name_offset = cur_offset + cpz.EntryNameOffset;
+ var name = Binary.GetCString (index, name_offset, cur_entries_end - name_offset);
if (!is_root_dir)
name = Path.Combine (dir_name, name);
var entry = FormatCatalog.Instance.Create (name);
entry.Offset = LittleEndian.ToInt64 (index, cur_offset+4) + base_offset;
entry.Size = LittleEndian.ToUInt32 (index, cur_offset+0xC);
- entry.CheckSum = LittleEndian.ToUInt32 (index, cur_offset+0x10);
- entry.Key = LittleEndian.ToUInt32 (index, cur_offset+0x14) + dir_key;
+ int key_offset = cur_offset + 0x10;
+ if (cpz.IsLongSize)
+ key_offset += 4;
+ entry.CheckSum = LittleEndian.ToUInt32 (index, key_offset);
+ entry.Key = LittleEndian.ToUInt32 (index, key_offset+4) + dir_key;
if (!entry.CheckPlacement (file.MaxOffset))
return null;
dir.Add (entry);
@@ -271,7 +229,8 @@ namespace GameRes.Formats.Purple
var data = carc.File.View.ReadBytes (entry.Offset, entry.Size);
if (carc.Header.IsEncrypted)
{
- uint key = (carc.Header.MasterKey ^ cent.Key) + (uint)carc.Header.DirCount - 0x5C29E87B;
+ uint key = (carc.Header.MasterKey ^ cent.Key) + (uint)carc.Header.DirCount;
+ key -= carc.Decoder.Scheme.EntrySubKey;
key ^= carc.Header.EntryKey;
carc.Decoder.DecryptEntry (data, carc.Header.CmvsMd5, key);
}
@@ -282,6 +241,21 @@ namespace GameRes.Formats.Purple
return new BinMemoryStream (data, entry.Name);
}
+ internal byte[] UnpackIndexKey (byte[] data, int offset, int length)
+ {
+ int key_offset = offset + 20;
+ int packed_offset = offset + 24;
+ int packed_length = length - 24;
+ for (int i = 0; i < packed_length; ++i)
+ {
+ data[packed_offset + i] ^= data[key_offset + (i & 3)];
+ }
+ int unpacked_length = data.ToInt32 (offset + 16);
+ var output = new byte[unpacked_length];
+ var decoder = new HuffmanDecoder (data, packed_offset, packed_length, output);
+ return decoder.Unpack();
+ }
+
void DecryptIndexStage1 (byte[] data, uint key, CmvsScheme scheme)
{
var secret = scheme.Cpz5Secret;
@@ -367,33 +341,6 @@ namespace GameRes.Formats.Purple
}
}
- public static uint CheckSum (byte[] data, int index, int length, uint crc)
- {
- if (null == data)
- throw new ArgumentNullException ("data");
- if (index < 0 || index > data.Length)
- throw new ArgumentOutOfRangeException ("index");
- if (length < 0 || length > data.Length || length > data.Length-index)
- throw new ArgumentException ("length");
- int dwords = length / 4;
- if (dwords > 0)
- {
- unsafe
- {
- fixed (byte* raw = &data[index])
- {
- uint* raw32 = (uint*)raw;
- for (int i = 0; i < dwords; ++i)
- crc += raw32[i];
- }
- }
- index += length & -4;
- }
- for (int i = 0; i < (length & 3); ++i)
- crc += data[index+i];
- return crc;
- }
-
byte[] UnpackPs2 (byte[] data)
{
DecryptPs2 (data);
@@ -471,6 +418,8 @@ namespace GameRes.Formats.Purple
protected byte[] m_decode_table = new byte[0x100];
protected CmvsScheme m_scheme;
+ public CmvsScheme Scheme { get { return m_scheme; } }
+
public Cpz5Decoder (CmvsScheme scheme, uint key, uint summand)
{
m_scheme = scheme;
diff --git a/ArcFormats/Cmvs/CmvsMD5.cs b/ArcFormats/Cmvs/CmvsMD5.cs
index 7042ec40..e68e7fea 100644
--- a/ArcFormats/Cmvs/CmvsMD5.cs
+++ b/ArcFormats/Cmvs/CmvsMD5.cs
@@ -27,7 +27,7 @@ using GameRes.Utility;
namespace GameRes.Formats.Cmvs
{
- public enum Md5Variant { A, B, Chrono, Memoria, Natsu }
+ public enum Md5Variant { A, B, Chrono, Memoria, Natsu, Aoi }
public abstract class MD5 : Cryptography.MD5Base
{
@@ -45,6 +45,7 @@ namespace GameRes.Formats.Cmvs
case Md5Variant.Chrono: return new Md5Chrono();
case Md5Variant.Memoria: return new Md5Memoria();
case Md5Variant.Natsu: return new Md5Natsu();
+ case Md5Variant.Aoi: return new Md5Aoi();
default: throw new System.ArgumentException ("Unknown MD5 variant", "variant");
}
}
@@ -151,4 +152,23 @@ namespace GameRes.Formats.Cmvs
data[3] = m_state[0] ^ 0xE3F9A742;
}
}
+
+ public class Md5Aoi : MD5
+ {
+ protected override void InitState ()
+ {
+ m_state[0] = 0xC74A2B02;
+ m_state[1] = 0xE7C8AB8F;
+ m_state[2] = 0x38BEBC4E;
+ m_state[3] = 0x7531A4C3;
+ }
+
+ protected override void SetResult (uint[] data)
+ {
+ data[0] = m_state[2] ^ 0x53A76D2E;
+ data[1] = m_state[1] + 0x5BB17FDA;
+ data[2] = m_state[0] + 0x6853E14D;
+ data[3] = m_state[3] ^ 0xF5C6A9A3;
+ }
+ }
}
diff --git a/ArcFormats/Cmvs/CpzHeader.cs b/ArcFormats/Cmvs/CpzHeader.cs
new file mode 100644
index 00000000..630718a1
--- /dev/null
+++ b/ArcFormats/Cmvs/CpzHeader.cs
@@ -0,0 +1,175 @@
+//! \file CpzHeader.cs
+//! \date 2017 Nov 27
+//! \brief CPZ archives header class.
+//
+// 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;
+using System.Collections.Generic;
+using System.Linq;
+using System.Security.Cryptography;
+using GameRes.Utility;
+
+namespace GameRes.Formats.Purple
+{
+ internal class CpzHeader
+ {
+ public int Version;
+ public int DirCount;
+ public int DirEntriesSize;
+ public int FileEntriesSize;
+ public uint[] CmvsMd5 = new uint[4];
+ public uint MasterKey;
+ public bool IsEncrypted;
+ public uint EntryKey;
+ public int IndexKeySize;
+ public uint Checksum;
+
+ public uint InitChecksum = 0x923A564Cu;
+ public uint IndexOffset;
+ public uint IndexSize;
+ public IEnumerable IndexMd5;
+ public int EntryNameOffset;
+
+ public bool IsLongSize { get { return Version > 6; } }
+
+ public static CpzHeader Parse (ArcView file)
+ {
+ var cpz = new CpzHeader { Version = file.View.ReadByte (3) - '0' };
+ int checksum_length;
+ byte[] header;
+ if (cpz.Version < 7)
+ {
+ header = file.View.ReadBytes (0, 0x40);
+ if (cpz.Version < 6)
+ cpz.ParseV5 (header);
+ else
+ cpz.ParseV6 (header);
+ cpz.IndexOffset = 0x40;
+ cpz.IndexSize = (uint)(cpz.DirEntriesSize + cpz.FileEntriesSize);
+ cpz.Checksum = header.ToUInt32 (0x3C);
+ checksum_length = 0x3C;
+ }
+ else
+ {
+ header = file.View.ReadBytes (0, 0x48);
+ cpz.ParseV7 (header);
+ cpz.IndexOffset = 0x48;
+ cpz.IndexSize = (uint)(cpz.DirEntriesSize + cpz.FileEntriesSize + cpz.IndexKeySize);
+ cpz.Checksum = header.ToUInt32 (0x44);
+ checksum_length = 0x40;
+ }
+ if (cpz.Checksum != CheckSum (header, 0, checksum_length, cpz.InitChecksum))
+ return null;
+
+ cpz.IndexMd5 = header.Skip (0x10).Take (0x10).ToArray();
+ return cpz;
+ }
+
+ private void ParseV5 (byte[] header)
+ {
+ DirCount = -0x1C5AC27 ^ LittleEndian.ToInt32 (header, 4);
+ DirEntriesSize = 0x37F298E7 ^ LittleEndian.ToInt32 (header, 8);
+ FileEntriesSize = 0x7A6F3A2C ^ LittleEndian.ToInt32 (header, 0x0C);
+ MasterKey = 0xAE7D39BF ^ LittleEndian.ToUInt32 (header, 0x30);
+ IsEncrypted = 0 != (0xFB73A955 ^ LittleEndian.ToUInt32 (header, 0x34));
+ EntryKey = 0;
+ EntryNameOffset = 0x18;
+ CmvsMd5[0] = 0x43DE7C19 ^ LittleEndian.ToUInt32 (header, 0x20);
+ CmvsMd5[1] = 0xCC65F415 ^ LittleEndian.ToUInt32 (header, 0x24);
+ CmvsMd5[2] = 0xD016A93C ^ LittleEndian.ToUInt32 (header, 0x28);
+ CmvsMd5[3] = 0x97A3BA9A ^ LittleEndian.ToUInt32 (header, 0x2C);
+ }
+
+ private void ParseV6 (byte[] header)
+ {
+ uint entry_key = 0x37ACF832 ^ LittleEndian.ToUInt32 (header, 0x38);
+ DirCount = -0x1C5AC26 ^ LittleEndian.ToInt32 (header, 4);
+ DirEntriesSize = 0x37F298E8 ^ LittleEndian.ToInt32 (header, 8);
+ FileEntriesSize = 0x7A6F3A2D ^ LittleEndian.ToInt32 (header, 0x0C);
+ MasterKey = 0xAE7D39B7 ^ LittleEndian.ToUInt32 (header, 0x30);
+ IsEncrypted = 0 != (0xFB73A956 ^ LittleEndian.ToUInt32 (header, 0x34));
+ EntryKey = 0x7DA8F173 * Binary.RotR (entry_key, 5) + 0x13712765;
+ EntryNameOffset = 0x18;
+ CmvsMd5[0] = 0x43DE7C1A ^ LittleEndian.ToUInt32 (header, 0x20);
+ CmvsMd5[1] = 0xCC65F416 ^ LittleEndian.ToUInt32 (header, 0x24);
+ CmvsMd5[2] = 0xD016A93D ^ LittleEndian.ToUInt32 (header, 0x28);
+ CmvsMd5[3] = 0x97A3BA9B ^ LittleEndian.ToUInt32 (header, 0x2C);
+ }
+
+ private void ParseV7 (byte[] header)
+ {
+ ParseV6 (header);
+ var index_key_size = LittleEndian.ToInt32 (header, 0x40);
+ IndexKeySize = 0x65EF99F3 ^ index_key_size;
+ InitChecksum = (uint)index_key_size - 0x6DC5A9B4u;
+ EntryNameOffset = 0x1C;
+ }
+
+ public bool VerifyIndex (byte[] index)
+ {
+ if (index.Length != (int)IndexSize)
+ return false;
+ using (var md5 = MD5.Create())
+ {
+ var hash = md5.ComputeHash (index);
+ if (!hash.SequenceEqual (IndexMd5))
+ return false;
+ if (Version > 6 && IndexKeySize > 0x10)
+ {
+ int index_size = DirEntriesSize + FileEntriesSize;
+ hash = md5.ComputeHash (index, index_size+0x10, IndexKeySize-0x10);
+ if (!hash.SequenceEqual (index.Skip (index_size).Take (0x10)))
+ return false;
+ }
+ return true;
+ }
+ }
+
+ public static uint CheckSum (byte[] data, int index, int length, uint crc)
+ {
+ if (null == data)
+ throw new ArgumentNullException ("data");
+ if (index < 0 || index > data.Length)
+ throw new ArgumentOutOfRangeException ("index");
+ if (length < 0 || length > data.Length || length > data.Length-index)
+ throw new ArgumentException ("length");
+ int dwords = length / 4;
+ if (dwords > 0)
+ {
+ unsafe
+ {
+ fixed (byte* raw = &data[index])
+ {
+ uint* raw32 = (uint*)raw;
+ for (int i = 0; i < dwords; ++i)
+ crc += raw32[i];
+ }
+ }
+ index += length & -4;
+ }
+ for (int i = 0; i < (length & 3); ++i)
+ crc += data[index+i];
+ return crc;
+ }
+ }
+}
diff --git a/ArcFormats/Cmvs/HuffmanDecoder.cs b/ArcFormats/Cmvs/HuffmanDecoder.cs
new file mode 100644
index 00000000..9e5842bb
--- /dev/null
+++ b/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;
+ }
+ }
+}