Files
Aaru/DiscImageChef.DiscImages/HDCopy/Identify.cs

79 lines
3.1 KiB
C#

// /***************************************************************************
// The Disc Image Chef
// ----------------------------------------------------------------------------
//
// Filename : Identify.cs
// Author(s) : Natalia Portillo <claunia@claunia.com>
//
// Component : Disk image plugins.
//
// --[ Description ] ----------------------------------------------------------
//
// Identifies HD-Copy disk images.
//
// --[ License ] --------------------------------------------------------------
//
// This library is free software; you can redistribute it and/or modify
// it under the terms of the GNU Lesser General Public License as
// published by the Free Software Foundation; either version 2.1 of the
// License, or (at your option) any later version.
//
// This library is distributed in the hope that it will be useful, but
// WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
// Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public
// License along with this library; if not, see <http://www.gnu.org/licenses/>.
//
// ----------------------------------------------------------------------------
// Copyright © 2017 Michael Drüing
// Copyright © 2011-2018 Natalia Portillo
// ****************************************************************************/
using System;
using System.IO;
using System.Runtime.InteropServices;
using DiscImageChef.CommonTypes.Interfaces;
namespace DiscImageChef.DiscImages
{
public partial class HdCopy
{
public bool Identify(IFilter imageFilter)
{
Stream stream = imageFilter.GetDataForkStream();
stream.Seek(0, SeekOrigin.Begin);
if(stream.Length < 2 + 2 * 82) return false;
byte[] header = new byte[2 + 2 * 82];
stream.Read(header, 0, 2 + 2 * 82);
IntPtr hdrPtr = Marshal.AllocHGlobal(2 + 2 * 82);
Marshal.Copy(header, 0, hdrPtr, 2 + 2 * 82);
HdcpFileHeader fheader = (HdcpFileHeader)Marshal.PtrToStructure(hdrPtr, typeof(HdcpFileHeader));
Marshal.FreeHGlobal(hdrPtr);
/* Some sanity checks on the values we just read.
* We know the image is from a DOS floppy disk, so assume
* some sane cylinder and sectors-per-track count.
*/
if(fheader.sectorsPerTrack < 8 || fheader.sectorsPerTrack > 40) return false;
if(fheader.lastCylinder < 37 || fheader.lastCylinder >= 82) return false;
// Validate the trackmap. First two tracks need to be present
if(fheader.trackMap[0] != 1 || fheader.trackMap[1] != 1) return false;
// all other tracks must be either present (=1) or absent (=0)
for(int i = 0; i < 2 * 82; i++)
if(fheader.trackMap[i] > 1)
return false;
// TODO: validate the tracks
// For now, having a valid header should be sufficient.
return true;
}
}
}