GARbro-mirror/ArcFormats/CsWare/ArcPCS.cs

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//! \file ArcPCS.cs
//! \date Mon Jan 25 01:36:53 2016
//! \brief C's ware resource archive.
//
// Copyright (C) 2016 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.ComponentModel.Composition;
using System.IO;
using System.Security.Cryptography;
using GameRes.Cryptography;
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using GameRes.Utility;
namespace GameRes.Formats.CsWare
{
internal class PcsEntry : Entry
{
public byte Key;
public uint NameHash; // used in archives version 6
}
internal class PcsArchive : ArcFile
{
public readonly int Version;
public PcsArchive (ArcView arc, ArchiveFormat impl, ICollection<Entry> dir, int version)
: base (arc, impl, dir)
{
Version = version;
}
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}
[Export(typeof(ArchiveFormat))]
public class PcsOpener : ArchiveFormat
{
public override string Tag { get { return "PCS"; } }
public override string Description { get { return "C's ware resource archive"; } }
public override uint Signature { get { return 0x53434350; } } // 'PCCS'
public override bool IsHierarchic { get { return false; } }
public override bool CanWrite { get { return false; } }
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public override ArcFile TryOpen (ArcView file)
{
int version = file.View.ReadUInt16 (4);
if (version < 1 || version > 6)
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return null;
int count = file.View.ReadInt32 (8);
if (!IsSaneCount (count))
return null;
uint data_offset = file.View.ReadUInt32 (12);
uint index_size = data_offset - 0x10;
var index = file.View.ReadBytes (0x10, index_size);
if (6 == version)
{
index = ShuffleBlocks (index, file.View.ReadUInt16 (6));
}
int index_offset = 0;
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var dir = new List<Entry> (count);
for (int i = 0; i < count; ++i)
{
int name_length;
if (version > 1)
{
name_length = LittleEndian.ToInt32 (index, index_offset);
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if (0 == name_length)
break;
if (name_length > index_size)
return null;
index_offset += 5 + name_length;
}
name_length = LittleEndian.ToInt32 (index, index_offset);
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if (0 == name_length)
break;
if (name_length > index_size)
return null;
index_offset += 5;
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byte checksum;
var name = DecryptName (index, index_offset, name_length, out checksum);
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Entry entry;
if (version >= 4)
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{
var pcs_entry = FormatCatalog.Instance.Create<PcsEntry> (name);
entry = pcs_entry;
pcs_entry.Key = checksum;
if (6 == version)
pcs_entry.NameHash = ComputeHash (index, index_offset, name_length-1);
index_offset += name_length;
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int c = -1 - checksum;
for (int j = 0; j < 4; ++j)
{
byte key = (byte)((checksum + (17 << j)) & 0x33);
index[index_offset+j] = (byte)(c + key - index[index_offset+j]);
index[index_offset+j+4] = (byte)(c + key - index[index_offset+j+4]);
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}
}
else
{
index_offset += name_length;
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entry = FormatCatalog.Instance.Create<Entry> (name);
}
if (index_offset > data_offset)
return null;
entry.Offset = LittleEndian.ToUInt32 (index, index_offset) + data_offset;
entry.Size = LittleEndian.ToUInt32 (index, index_offset+4);
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if (!entry.CheckPlacement (file.MaxOffset))
return null;
dir.Add (entry);
index_offset += 0x10;
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}
if (0 == dir.Count)
return null;
return new PcsArchive (file, this, dir, version);
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}
public override Stream OpenEntry (ArcFile arc, Entry entry)
{
var pent = entry as PcsEntry;
var parc = arc as PcsArchive;
if (null == pent || null == parc)
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return base.OpenEntry (arc, entry);
uint header_size = Math.Min (entry.Size, 512u);
var header = arc.File.View.ReadBytes (entry.Offset, header_size);
if (6 == parc.Version)
{
header = ShuffleBlocks (header, pent.NameHash);
}
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for (int i = 0; i < header.Length; ++i)
{
header[i] = (byte)(pent.Key - header[i] - 1);
}
if (header_size == entry.Size)
return new MemoryStream (header);
var rest = arc.File.CreateStream (entry.Offset+512, entry.Size-512);
return new PrefixStream (header, rest);
}
string DecryptName (byte[] name_buffer, int offset, int length, out byte checksum)
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{
int count;
checksum = 0;
for (count = 0; count < length; ++count)
{
if (0 == name_buffer[offset+count])
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break;
name_buffer[offset+count] = Binary.RotByteL (name_buffer[offset+count], 4);
checksum += name_buffer[offset+count];
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}
return Encodings.cp932.GetString (name_buffer, offset, count);
}
byte[] ShuffleBlocks (byte[] input, uint key)
{
int block_size = input.Length >> 5;
var output = new byte[input.Length];
var twister = new MersenneTwister (key);
int copied_sections = 0;
for (int i = 0; i < 0x20; ++i)
{
int j = (int)(twister.Rand() & 0x1F);
while (0 != (copied_sections & (1 << j)))
j = (j + 1) & 0x1F;
copied_sections |= 1 << j;
Buffer.BlockCopy (input, j * block_size, output, i * block_size, block_size);
}
int shuffled = block_size << 5;
if (shuffled != input.Length)
Buffer.BlockCopy (input, shuffled, output, shuffled, input.Length-shuffled);
return output;
}
static readonly Lazy<HashAlgorithm> SHA1 = new Lazy<HashAlgorithm> (() => System.Security.Cryptography.SHA1.Create());
uint ComputeHash (byte[] data, int offset, int length)
{
var hash = SHA1.Value.ComputeHash (data, offset, length);
return BigEndian.ToUInt32 (hash, 0);
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}
}
}