public static CHSVolume Load(String source, Byte[] data)
{
// header
if (!HasHeader(data))
{
return(null);
}
Int32 p = 0;
Byte b = data[p++];
Byte b2 = data[p++];
Boolean adc = false;
if ((b == (Byte)'t') && (b2 == (Byte)'d'))
{
adc = true;
}
else if ((b != (Byte)'T') || (b2 != (Byte)'D'))
{
Debug.WriteLine(1, "File does not appear to be TeleDisk format (no TD header)");
return(null);
}
if ((b = data[p++]) != 0)
{
Debug.WriteLine(1, "Multi-file images not supported (volume sequence is {0:D0}, expect 0)", b);
return(null);
}
p++; // skip check signature byte
p++; // skip version number byte
p++; // skip source density byte
p++; // skip drive type byte
Int32 stepping = data[p++];
p++; // skip dos mode byte
Int32 nh = data[p++]; // number of sides
p += 2; // header CRC
if (adc)
{
LZSS.Decompressor D = new LZSS.Decompressor(data, p);
data = D.GetBytes();
p = 0;
}
// comment block
Int32 n;
String info = source;
if ((stepping & 0x80) != 0)
{
if (p + 10 >= data.Length)
{
return(null);
}
p += 2; // CRC
n = Buffer.GetUInt16L(data, ref p);
p += 6; // date/time
StringBuilder buf = new StringBuilder(n);
for (Int32 i = 0; i < n; i++)
{
b = Buffer.GetByte(data, ref p);
buf.Append((b == 0) ? '\n' : (Char)b);
}
info = buf.ToString();
}
// determine disk geometry
Int32 q = p;
Int32 nc = -1;
Int32[] ct = new Int32[256];
while (p < data.Length)
{
// track header
Int32 ns = Buffer.GetByte(data, ref p); // number of sectors on this track
if (ns == 255)
{
break;
}
Int32 c = Buffer.GetByte(data, ref p) + 1;
if (c > nc)
{
nc = c;
}
Int32 h = Buffer.GetByte(data, ref p) + 1;
if (h > nh)
{
nh = h;
}
p++; // CRC
// sectors
for (Int32 s = 0; s < ns; s++)
{
// sector header
p++; // skip cylinder id
p++; // skip side id
p++; // skip sector id
b = Buffer.GetByte(data, ref p); // sector size
ct[b]++;
Byte f = Buffer.GetByte(data, ref p); // flags
p++; // skip CRC
if ((f & 0x30) != 0)
{
continue;
}
n = Buffer.GetUInt16L(data, ref p);
p += n;
}
}
Int32 ss = -1;
n = 0;
for (Int32 i = 0; i < 256; i++)
{
if (ct[i] > n)
{
n = ct[i];
ss = 128 << i;
}
}
CHSVolume vol = new CHSVolume(source, source, ss, nc, nh);
// track data
p = q;
while (p < data.Length)
{
// track header
Int32 ns = Buffer.GetByte(data, ref p); // number of sectors on this track
if (ns == 255)
{
break;
}
Int32 c = Buffer.GetByte(data, ref p);
Int32 h = Buffer.GetByte(data, ref p);
p++; // CRC
Track T = new Track(ns);
vol[c, h] = T;
// sectors
for (Int32 s = 0; s < ns; s++)
{
// sector header
p++; // skip cylinder id
p++; // skip side id
Int32 id = Buffer.GetByte(data, ref p); // sector id
n = 128 << Buffer.GetByte(data, ref p); // sector size
Byte f = Buffer.GetByte(data, ref p); // flags
p++; // skip CRC
if ((f & 0x30) != 0)
{
continue;
}
Int32 l = Buffer.GetUInt16L(data, ref p) - 1;
switch (Buffer.GetByte(data, ref p))
{
case 0:
T[s] = new Sector(id, n, data, p);
p += n;
break;
case 1:
T[s] = new Sector(id, n);
q = 0;
while (n > 0)
{
Int32 k = Buffer.GetUInt16L(data, ref p);
b = Buffer.GetByte(data, ref p);
b2 = Buffer.GetByte(data, ref p);
for (Int32 i = 0; i < k; i++)
{
T[s][q++] = b;
T[s][q++] = b2;
n -= 2;
}
}
break;
case 2:
T[s] = new Sector(id, n);
q = 0;
while (n > 0)
{
Int32 k = Buffer.GetByte(data, ref p);
if (k == 0)
{
k = Buffer.GetByte(data, ref p);
T[s].CopyFrom(data, p, q, k);
p += k;
q += k;
n -= k;
}
else
{
k *= 2;
Int32 z = Buffer.GetByte(data, ref p);
for (Int32 i = 0; i < z; i++)
{
T[s].CopyFrom(data, p, q, k);
q += k;
n -= k;
}
p += k;
}
}
break;
}
}
}
return(vol);
}
public static CHSVolume Load(String source, Byte[] data)
{
if (!IsValid(data))
{
return(null);
}
Int32 z1 = 29, z2 = 27, z3 = 25, z4 = 23;
Int32 nt = 154;
CHSVolume V = new CHSVolume(source, source, 256, 1, nt, 0, 1, 0);
for (Int32 t = 1; t <= 39; t++)
{
V[t, 0] = new Track(z1);
}
for (Int32 t = 40; t <= 53; t++)
{
V[t, 0] = new Track(z2);
}
for (Int32 t = 54; t <= 64; t++)
{
V[t, 0] = new Track(z3);
}
for (Int32 t = 65; t <= 77; t++)
{
V[t, 0] = new Track(z4);
}
for (Int32 t = 78; t <= 116; t++)
{
V[t, 0] = new Track(z1);
}
for (Int32 t = 117; t <= 130; t++)
{
V[t, 0] = new Track(z2);
}
for (Int32 t = 131; t <= 141; t++)
{
V[t, 0] = new Track(z3);
}
for (Int32 t = 142; t <= nt; t++)
{
V[t, 0] = new Track(z4);
}
Int32 p = 0;
Int32 q = (data.Length == V.BlockCount * 257) ? V.BlockCount * 256 : -1;
for (Int32 t = 1; t <= nt; t++)
{
Track T = V[t, 0];
for (Int32 s = 0; s < T.Length; s++)
{
Sector S = new Sector(s, 256, data, p);
p += 256;
if (q != -1)
{
S.ErrorCode = data[q++];
}
T[s] = S;
}
}
return(V);
}
