GARbro-mirror/ArcFormats/Cmvs/CpzHeader.cs

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2017-11-27 16:47:15 +08:00
//! \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<byte> 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;
}
}
}