chovy-sign/CHOVY-SIGN/DiscUtils/Iso9660/BootValidationEntry.cs

88 lines
2.9 KiB
C#

//
// Copyright (c) 2008-2011, Kenneth Bell
//
// 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 DiscUtils.Streams;
namespace DiscUtils.Iso9660
{
internal class BootValidationEntry
{
private readonly byte[] _data;
public byte HeaderId;
public string ManfId;
public byte PlatformId;
public BootValidationEntry()
{
HeaderId = 1;
PlatformId = 0;
ManfId = ".Net DiscUtils";
}
public BootValidationEntry(byte[] src, int offset)
{
_data = new byte[32];
Array.Copy(src, offset, _data, 0, 32);
HeaderId = _data[0];
PlatformId = _data[1];
ManfId = EndianUtilities.BytesToString(_data, 4, 24).TrimEnd('\0').TrimEnd(' ');
}
public bool ChecksumValid
{
get
{
ushort total = 0;
for (int i = 0; i < 16; ++i)
{
total += EndianUtilities.ToUInt16LittleEndian(_data, i * 2);
}
return total == 0;
}
}
internal void WriteTo(byte[] buffer, int offset)
{
Array.Clear(buffer, offset, 0x20);
buffer[offset + 0x00] = HeaderId;
buffer[offset + 0x01] = PlatformId;
EndianUtilities.StringToBytes(ManfId, buffer, offset + 0x04, 24);
buffer[offset + 0x1E] = 0x55;
buffer[offset + 0x1F] = 0xAA;
EndianUtilities.WriteBytesLittleEndian(CalcChecksum(buffer, offset), buffer, offset + 0x1C);
}
private static ushort CalcChecksum(byte[] buffer, int offset)
{
ushort total = 0;
for (int i = 0; i < 16; ++i)
{
total += EndianUtilities.ToUInt16LittleEndian(buffer, offset + i * 2);
}
return (ushort)(0 - total);
}
}
}