// /*************************************************************************** // The Disc Image Chef // ---------------------------------------------------------------------------- // // Filename : Read.cs // Author(s) : Michael Drüing // // Component : Disk image plugins. // // --[ Description ] ---------------------------------------------------------- // // Reads d2f 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 . // // ---------------------------------------------------------------------------- // Copyright © 2018-2019 Michael Drüing // Copyright © 2011-2019 Natalia Portillo // ****************************************************************************/ using System; using System.IO; using System.Runtime.InteropServices; using System.Text; using DiscImageChef.Checksums; using DiscImageChef.CommonTypes; using DiscImageChef.CommonTypes.Enums; using DiscImageChef.CommonTypes.Interfaces; using DiscImageChef.Console; namespace DiscImageChef.DiscImages { public partial class WCDiskImage { public bool Open(IFilter imageFilter) { string comments = string.Empty; Stream stream = imageFilter.GetDataForkStream(); stream.Seek(0, SeekOrigin.Begin); byte[] header = new byte[32]; stream.Read(header, 0, 32); IntPtr hdrPtr = Marshal.AllocHGlobal(32); Marshal.Copy(header, 0, hdrPtr, 32); WCDiskImageFileHeader fheader = (WCDiskImageFileHeader)Marshal.PtrToStructure(hdrPtr, typeof(WCDiskImageFileHeader)); Marshal.FreeHGlobal(hdrPtr); DicConsole.DebugWriteLine("d2f plugin", "Detected WC DISK IMAGE with {0} heads, {1} tracks and {2} sectors per track.", fheader.heads, fheader.cylinders, fheader.sectorsPerTrack); imageInfo.Cylinders = fheader.cylinders; imageInfo.SectorsPerTrack = fheader.sectorsPerTrack; imageInfo.SectorSize = 512; // only 512 bytes per sector supported imageInfo.Heads = fheader.heads; imageInfo.Sectors = imageInfo.Heads * imageInfo.Cylinders * imageInfo.SectorsPerTrack; imageInfo.ImageSize = imageInfo.Sectors * imageInfo.SectorSize; imageInfo.XmlMediaType = XmlMediaType.BlockMedia; imageInfo.CreationTime = imageFilter.GetCreationTime(); imageInfo.LastModificationTime = imageFilter.GetLastWriteTime(); imageInfo.MediaTitle = Path.GetFileNameWithoutExtension(imageFilter.GetFilename()); imageInfo.MediaType = Geometry.GetMediaType(((ushort)imageInfo.Cylinders, (byte)imageInfo.Heads, (ushort)imageInfo.SectorsPerTrack, 512, MediaEncoding.MFM, false)); /* buffer the entire disk in memory */ for(int cyl = 0; cyl < imageInfo.Cylinders; cyl++) { for(int head = 0; head < imageInfo.Heads; head++) ReadTrack(stream, cyl, head); } /* if there are extra tracks, read them as well */ if(fheader.extraTracks[0] == 1) { DicConsole.DebugWriteLine("d2f plugin", "Extra track 1 (head 0) present, reading"); ReadTrack(stream, (int)imageInfo.Cylinders, 0); } if(fheader.extraTracks[1] == 1) { DicConsole.DebugWriteLine("d2f plugin", "Extra track 1 (head 1) present, reading"); ReadTrack(stream, (int)imageInfo.Cylinders, 1); } if(fheader.extraTracks[2] == 1) { DicConsole.DebugWriteLine("d2f plugin", "Extra track 2 (head 0) present, reading"); ReadTrack(stream, (int)imageInfo.Cylinders + 1, 0); } if(fheader.extraTracks[3] == 1) { DicConsole.DebugWriteLine("d2f plugin", "Extra track 2 (head 1) present, reading"); ReadTrack(stream, (int)imageInfo.Cylinders + 1, 1); } /* adjust number of cylinders */ if(fheader.extraTracks[0] == 1 || fheader.extraTracks[1] == 1) imageInfo.Cylinders++; if(fheader.extraTracks[2] == 1 || fheader.extraTracks[3] == 1) imageInfo.Cylinders++; /* read the comment and directory data if present */ if(fheader.extraFlags.HasFlag(ExtraFlag.Comment)) { DicConsole.DebugWriteLine("d2f plugin", "Comment present, reading"); byte[] sheaderBuffer = new byte[6]; stream.Read(sheaderBuffer, 0, 6); IntPtr sectPtr = Marshal.AllocHGlobal(6); Marshal.Copy(sheaderBuffer, 0, sectPtr, 6); WCDiskImageSectorHeader sheader = (WCDiskImageSectorHeader)Marshal.PtrToStructure(sectPtr, typeof(WCDiskImageSectorHeader)); Marshal.FreeHGlobal(sectPtr); if(sheader.flag != SectorFlag.Comment) throw new InvalidDataException(string.Format("Invalid sector type '{0}' encountered", sheader.flag.ToString())); byte[] comm = new byte[sheader.crc]; stream.Read(comm, 0, sheader.crc); comments += Encoding.ASCII.GetString(comm) + Environment.NewLine; } if(fheader.extraFlags.HasFlag(ExtraFlag.Directory)) { DicConsole.DebugWriteLine("d2f plugin", "Directory listing present, reading"); byte[] sheaderBuffer = new byte[6]; stream.Read(sheaderBuffer, 0, 6); IntPtr sectPtr = Marshal.AllocHGlobal(6); Marshal.Copy(sheaderBuffer, 0, sectPtr, 6); WCDiskImageSectorHeader sheader = (WCDiskImageSectorHeader)Marshal.PtrToStructure(sectPtr, typeof(WCDiskImageSectorHeader)); Marshal.FreeHGlobal(sectPtr); if(sheader.flag != SectorFlag.Directory) throw new InvalidDataException(string.Format("Invalid sector type '{0}' encountered", sheader.flag.ToString())); byte[] dir = new byte[sheader.crc]; stream.Read(dir, 0, sheader.crc); comments += Encoding.ASCII.GetString(dir); } if(comments.Length > 0) imageInfo.Comments = comments; // save some variables for later use fileHeader = fheader; wcImageFilter = imageFilter; return true; } public byte[] ReadSector(ulong sectorAddress) { int sectorNumber = (int)(sectorAddress % imageInfo.SectorsPerTrack) + 1; int trackNumber = (int)(sectorAddress / imageInfo.SectorsPerTrack); int headNumber = imageInfo.Heads > 1 ? trackNumber % 2 : 0; int cylinderNumber = imageInfo.Heads > 1 ? trackNumber / 2 : trackNumber; if(badSectors[(cylinderNumber, headNumber, sectorNumber)]) { DicConsole.DebugWriteLine("d2f plugin", "reading bad sector {0} ({1},{2},{3})", sectorAddress, cylinderNumber, headNumber, sectorNumber); /* if we have sector data, return that */ if(sectorCache.ContainsKey((cylinderNumber, headNumber, sectorNumber))) return sectorCache[(cylinderNumber, headNumber, sectorNumber)]; /* otherwise, return an empty sector */ return new byte[512]; } return sectorCache[(cylinderNumber, headNumber, sectorNumber)]; } public byte[] ReadSectors(ulong sectorAddress, uint length) { byte[] result = new byte[length * imageInfo.SectorSize]; if(sectorAddress + length > imageInfo.Sectors) throw new ArgumentOutOfRangeException(nameof(length), "Requested more sectors than available"); for(int i = 0; i < length; i++) ReadSector(sectorAddress + (ulong)i).CopyTo(result, i * imageInfo.SectorSize); return result; } /// /// Read a whole track and cache it /// /// The stream to read from /// The cylinder number of the track being read. /// The head number of the track being read. void ReadTrack(Stream stream, int cyl, int head) { byte[] sectorData; byte[] crc; short calculatedCRC; for(int sect = 1; sect < imageInfo.SectorsPerTrack + 1; sect++) { /* read the sector header */ byte[] sheaderBuffer = new byte[6]; stream.Read(sheaderBuffer, 0, 6); IntPtr sectPtr = Marshal.AllocHGlobal(6); Marshal.Copy(sheaderBuffer, 0, sectPtr, 6); WCDiskImageSectorHeader sheader = (WCDiskImageSectorHeader)Marshal.PtrToStructure(sectPtr, typeof(WCDiskImageSectorHeader)); Marshal.FreeHGlobal(sectPtr); /* validate the sector header */ if(sheader.cylinder != cyl || sheader.head != head || sheader.sector != sect) throw new InvalidDataException(string.Format("Unexpected sector encountered. Found CHS {0},{1},{2} but expected {3},{4},{5}", sheader.cylinder, sheader.head, sheader.sector, cyl, head, sect)); sectorData = new byte[512]; /* read the sector data */ switch(sheader.flag) { case SectorFlag.Normal: /* read a normal sector and store it in cache */ stream.Read(sectorData, 0, 512); sectorCache[(cyl, head, sect)] = sectorData; Crc16Context.Data(sectorData, 512, out crc); calculatedCRC = (short)((256 * crc[0]) | crc[1]); /* DicConsole.DebugWriteLine("d2f plugin", "CHS {0},{1},{2}: Regular sector, stored CRC=0x{3:x4}, calculated CRC=0x{4:x4}", cyl, head, sect, sheader.crc, 256 * crc[0] + crc[1]); */ badSectors[(cyl, head, sect)] = sheader.crc != calculatedCRC; if(calculatedCRC != sheader.crc) DicConsole.DebugWriteLine("d2f plugin", "CHS {0},{1},{2}: CRC mismatch: stored CRC=0x{3:x4}, calculated CRC=0x{4:x4}", cyl, head, sect, sheader.crc, calculatedCRC); break; case SectorFlag.BadSector: /* DicConsole.DebugWriteLine("d2f plugin", "CHS {0},{1},{2}: Bad sector", cyl, head, sect); */ badSectors[(cyl, head, sect)] = true; break; case SectorFlag.RepeatByte: /* DicConsole.DebugWriteLine("d2f plugin", "CHS {0},{1},{2}: RepeatByte sector, fill byte 0x{0:x2}", cyl, head, sect, sheader.crc & 0xff); */ for(int i = 0; i < 512; i++) sectorData[i] = (byte)(sheader.crc & 0xff); sectorCache[(cyl, head, sect)] = sectorData; badSectors[(cyl, head, sect)] = false; break; default: throw new InvalidDataException(string.Format("Invalid sector type '{0}' encountered", sheader.flag.ToString())); } } } } }