// Get PX0 file image as a byte array. If the image contains compressed data,
// decompress it now, so returned bytes always reflect uncompressed state.
private static byte[] GetPX0ImageBytes(string fname)
{
const int teleGetHdrBytes = 22;
using (var binReader = new BinaryReader(File.Open(fname, FileMode.Open)))
{
// Read first 'TeleGetHdrBytes' bytes. These are never compressed.
byte[] firstBytes;
try
{
firstBytes = binReader.ReadBytes(teleGetHdrBytes);
}
catch
{
throw new Exception(string.Format("'{0}' NOT a TeleGet file! (Missing header?)", fname));
}
byte[] buf = null;
if (firstBytes[0] == 't' && firstBytes[1] == 'd')
{
// If 1st 2 bytes are lower case 'td' then data following
// header has been compressed. Decompress now.
buf = Decompress.GetDecompressedBytes(binReader);
}
else if (firstBytes[0] == 'T' && firstBytes[1] == 'D')
{
// If 1st 2 bytes are upper case 'TD' then data following
// header has NOT compressed. Just read it.
var buffer = new byte[16 * 1024];
using (var ms = new MemoryStream())
{
int read;
while ((read = binReader.Read(buffer, 0, buffer.Length)) > 0)
{
ms.Write(buffer, 0, read);
}
buf = ms.ToArray();
}
}
else
{
throw new Exception(string.Format("'{0}' NOT a TeleGet file!", fname));
}
if (null == buf || buf.Length < 1)
{
return(null); // No data after header?
}
var decodedData = new byte[buf.Length + firstBytes.Length];
firstBytes.CopyTo(decodedData, 0);
buf.CopyTo(decodedData, firstBytes.Length);
return(decodedData);
}
}
/*
* Get decompressed bytes. Note that this is not implemented with a view for speed.
*/
public static byte[] GetDecompressedBytes(BinaryReader reader)
{
using (var dcomp = new Decompress(reader))
using (var memStream = new MemoryStream())
{
for (;;)
{
int c = dcomp.Getbyte();
if (c < 0)
{
break; // EOF found!
}
memStream.WriteByte((byte)c);
}
return(memStream.ToArray());
}
}
