public override void WriteSector(int track, int head, int sector, byte[] buffer)
{
int sectorLength = 0;
int offset = GetSectorOffset(track, head, sector, ref sectorLength);
if (buffer.Length != sectorLength)
{
throw new IOException();
}
if (offset != 0 && sectorLength != 0)
{
byte[] crc = Crc16.ComputeChecksumBytes(0xE295, buffer);
WriteBytes(offset, buffer);
WriteByte(offset + buffer.Length, crc[1]);
WriteByte(offset + buffer.Length + 1, crc[0]);
}
}
/// <summary>
/// Create DMK basic disk structure on disk image
/// </summary>
private void LowLevelFormat()
{
// Prepare blank sector data
byte[] sectorData = new byte[this.PhysicalSectorSize];
byte[] sectorCRC = Crc16.ComputeChecksumBytes(0xe295, sectorData);
for (int track = 0; track < this.PhysicalTracks; track++)
{
for (int head = 0; head < this.PhysicalHeads; head++)
{
byte[] trackData = new byte[this.trackSize];
// First, create the IDAM table
byte[] idamtable = new byte[128];
for (int i = 0, sectorOffset = 0x80ab; i < this.PhysicalSectors; i++, sectorOffset += 338)
{
idamtable[i * 2] = (byte)(sectorOffset & 0xff);
idamtable[(i * 2) + 1] = (byte)(sectorOffset >> 8);
}
Array.Copy(idamtable, 0, trackData, 0, idamtable.Length);
// Now lets make the track
Array.Copy(new byte[32].Initialize(0x4e), 0, trackData, idamtable.Length, 32);
// Lets create each sector
int interleavedSector = 1;
for (int sector = 1; sector < this.PhysicalSectors; sector++)
{
// Sector Preamble part
byte[] sectorPreamble = new byte[56].Initialize(0x4e);
Array.Copy(new byte[0x08], 0, sectorPreamble, 0, 0x08);
Array.Copy(new byte[0x03].Initialize(0xa1), 0, sectorPreamble, 0x08, 3);
byte[] sectorControl = new byte[] { 0xfe, (byte)track, (byte)head, (byte)sector, 0x01 };
Array.Copy(sectorControl, 0, sectorPreamble, 0x0b, 5);
byte[] sectorControlCRC = Crc16.ComputeChecksumBytes(0xcdb4, sectorControl);
sectorPreamble[0x10] = sectorControlCRC[1];
sectorPreamble[0x11] = sectorControlCRC[0];
Array.Copy(new byte[12], 0, sectorPreamble, 0x28, 12);
Array.Copy(new byte[3].Initialize(0xa1), 0, sectorPreamble, 0x34, 3);
sectorPreamble[0x37] = 0xfb;
// Sector Post-amble part
byte[] sectorPostamble = new byte[26].Initialize(0x4e);
sectorPostamble[0] = sectorCRC[1];
sectorPostamble[1] = sectorCRC[0];
// Write the parts to the track data
int trackOffset = idamtable.Length + ((interleavedSector - 1) * 338) + 32;
Array.Copy(sectorPreamble, 0, trackData, trackOffset, sectorPreamble.Length);
Array.Copy(sectorData, 0, trackData, trackOffset + 56, sectorData.Length);
Array.Copy(sectorPostamble, 0, trackData, trackOffset + 312, sectorPostamble.Length);
// Calculate next interleaved sector position
interleavedSector += this.Interleave;
if (interleavedSector > this.PhysicalSectors)
{
interleavedSector -= this.PhysicalSectors;
}
if (interleavedSector < this.Interleave)
{
interleavedSector++;
}
}
// Write out the track
this.WriteBytes(this.HeaderLength + (track * this.PhysicalHeads * this.trackSize) + (head * this.trackSize), trackData);
}
}
}
/// <summary>
/// Initializes a new instance of the <see cref="Crc16CalculatorStream"/> class.
/// </summary>
/// <param name="stream">Base stream to perform operations on</param>
/// <param name="length">Maximum number of stream bytes to process</param>
/// <param name="leaveOpen">Leave the base stream open once operations are complete</param>
/// <param name="crc16">Initial crc register value</param>
public Crc16CalculatorStream(System.IO.Stream stream, long length, bool leaveOpen, Crc16 crc16)
: this(leaveOpen, length, stream, crc16)
{
if (length < 0)
{
throw new ArgumentException("length");
}
}
/// <summary>
/// Initializes a new instance of the <see cref="Crc16CalculatorStream"/> class.
/// </summary>
/// <param name="leaveOpen">Leave the base stream open once operations are complete</param>
/// <param name="length">Maximum number of stream bytes to process</param>
/// <param name="stream">Base stream to perform operations on</param>
/// <param name="crc16">Initial crc register value</param>
private Crc16CalculatorStream(bool leaveOpen, long length, System.IO.Stream stream, Crc16 crc16)
: base()
{
this.innerStream = stream;
this.crc16 = crc16 ?? new Crc16();
this.lengthLimit = length;
this.leaveOpen = leaveOpen;
}
private int GetSectorOffset(int track, int head, int sector, ref int sectorsize)
{
int offset = 0;
sectorsize = 0;
int trackoffset = this.HeaderLength + (track * this.PhysicalHeads * this.trackLength) + (head * this.trackLength);
int idamOffset = 0;
int i = 0;
byte[] idam = new byte[0];
// Search for sector
for (i = 0; i < DMK_TOK_LEN; i++)
{
idamOffset = ((this.ReadByte(trackoffset + (i * 2) + 1) << 8) + this.ReadByte(trackoffset + (i * 2))) & 0x3fff;
if (idamOffset == 0)
{
i = DMK_TOK_LEN;
break;
}
if ((idamOffset + DMK_IDAM_LENGTH) > trackLength)
{
continue;
}
int idamCRC = (this.ReadByte(trackoffset + idamOffset + 5) << 8) + this.ReadByte(trackoffset + idamOffset + 6);
idam = this.ReadBytes(trackoffset + idamOffset, DMK_IDAM_LENGTH - 2);
int calcCRC = Crc16.ComputeChecksum(0xCDB4, idam);
if (idamCRC == calcCRC)
{
if (sector == idam[3] && track == idam[1] && head == idam[2])
{
break;
}
}
}
if (i >= DMK_TOK_LEN)
{
throw new SectorNotFoundException();
}
int state = 0;
int offs = idamOffset + DMK_IDAM_LENGTH;
for (i = 0; i < DMK_DATA_GAP; i++)
{
if ((i + offs) > trackLength)
{
throw new SectorNotFoundException();
}
if (this.ReadByte(trackoffset + offs + i) == 0xA1)
{
state++;
}
else if ((this.ReadByte(trackoffset + offs + i) == 0xFB) && state > 0)
{
break;
}
else
{
state = 0;
}
}
if (i >= DMK_DATA_GAP)
{
throw new SectorNotFoundException();
}
offs += i + 1;
int sec_len = 128 << idam[4];
if ((offs + sec_len) > trackLength)
{
throw new SectorNotFoundException();
}
offset = trackoffset + offs;
sectorsize = sec_len;
return(offset);
}
public override void CreateDisk(string filename, int tracks, int heads, int sectors, int sectorsize, byte filldata)
{
if (this.baseStream != null)
{
this.baseStream.Close();
this.baseStream = null;
}
this.filename = filename;
try
{
this.baseStream = File.Open(this.filename, FileMode.Create, FileAccess.ReadWrite, FileShare.Read);
physicalTracks = tracks;
physicalHeads = heads;
physicalSectors = sectors;
physicalSectorSize = sectorsize;
trackLength = DMK_DEFAULT_TRACK_LENGTH;
byte[] sectorData = new byte[this.PhysicalSectorSize].Initialize(filldata);
byte[] sectorCRC = Crc16.ComputeChecksumBytes(0xE295, sectorData);
byte[] header = new byte[] { 0, (byte)this.PhysicalTracks, (byte)(this.trackLength & 0xff), (byte)(this.trackLength >> 8), (byte)(((this.PhysicalHeads > 1) ? 0 : 1) << 4), 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 };
headerLength = header.Length;
this.baseStream.Write(header, 0, HeaderLength);
for (int t = 0; t < PhysicalTracks; t++)
{
for (int h = 0; h < PhysicalHeads; h++)
{
byte[] trackData = new byte[trackLength].Initialize(0x4E);
for (int i = 0; i < 128; i++)
{
trackData[i] = 0;
}
int[] sPointers = new int[PhysicalSectors];
for (int s = 0, i = 0x80AB; s < PhysicalSectors; s++, i += 338)
{
sPointers[s] = i;
trackData[2 * s] = (byte)(i & 0xff);
trackData[2 * s + 1] = (byte)(i >> 8);
}
int SectorID = 1;
for (int s = 0; s < PhysicalSectors; s++)
{
int sectorOffset = (sPointers[SectorID - 1] & 0x3fff) - 11;
for (int i = 0; i < 8; i++)
{
trackData[sectorOffset++] = 0;
}
for (int i = 0; i < 3; i++)
{
trackData[sectorOffset++] = 0xA1;
}
byte[] sectorControl = new byte[] { 0xFE, (byte)t, (byte)h, (byte)(s + 1), (byte)((PhysicalSectorSize / 128) >> 1) };
byte[] sectorControlCRC = Crc16.ComputeChecksumBytes(0xCDB4, sectorControl);
Array.Copy(sectorControl, 0, trackData, sectorOffset, 5);
sectorOffset += 5;
trackData[sectorOffset++] = sectorControlCRC[1];
trackData[sectorOffset++] = sectorControlCRC[0];
sectorOffset += 22;
for (int i = 0; i < 12; i++)
{
trackData[sectorOffset++] = 0;
}
for (int i = 0; i < 3; i++)
{
trackData[sectorOffset++] = 0xA1;
}
trackData[sectorOffset++] = 0xFB;
Array.Copy(sectorData, 0, trackData, sectorOffset, PhysicalSectorSize);
sectorOffset += PhysicalSectorSize;
trackData[sectorOffset++] = sectorCRC[1];
trackData[sectorOffset++] = sectorCRC[0];
if (s < PhysicalSectors - 1)
{
SectorID++;
SectorID += interleave;
if (SectorID > PhysicalSectors)
{
SectorID -= PhysicalSectors;
}
while (trackData[sPointers[SectorID - 1] & 0x3FFF] == 0xFE)
{
SectorID++;
}
if (SectorID > PhysicalSectors)
{
throw new IOException();
}
}
}
this.baseStream.Write(trackData, 0, trackData.Length);
}
}
}
catch (IOException)
{
MessageBox.Show(string.Format(MainForm.ResourceManager.GetString("DiskImageBase_FileOpenError", MainForm.CultureInfo), this.filename), MainForm.ResourceManager.GetString("DiskImageBase_FileOpenErrorCaption", MainForm.CultureInfo), MessageBoxButtons.OK, MessageBoxIcon.Error);
this.filename = string.Empty;
}
}
