So I have this:
public static long FindPosition(Stream stream, byte[] byteSequence)
{
if (byteSequence.Length > stream.Length)
return -1;
byte[] buffer = new byte[byteSequence.Length];
using (BufferedStream bufStream = new BufferedStream(stream, byteSequence.Length))
{
int i;
while ((i = bufStream.Read(buffer, 0, byteSequence.Length)) == byteSequence.Length)
{
if (byteSequence.SequenceEqual(buffer))
return bufStream.Position - byteSequence.Length;
else
bufStream.Position -= byteSequence.Length - PadLeftSequence(buffer, byteSequence);
}
}
return -1;
}
private static int PadLeftSequence(byte[] bytes, byte[] seqBytes)
{
int i = 1;
while (i < bytes.Length)
{
int n = bytes.Length - i;
byte[] aux1 = new byte[n];
byte[] aux2 = new byte[n];
Array.Copy(bytes, i, aux1, 0, n);
Array.Copy(seqBytes, aux2, n);
if (aux1.SequenceEqual(aux2))
return i;
i++;
}
return i;
}
Which works perfectly to get an offset that has a specific set of bytes, but now I want to do the inverse, find a set of bytes from a specific offset. How can I do that?
Try this example:
long offset = 100L; // Offset
int bytesCount = 20; // Number of bytes to read
byte[] buffer = new byte[bytesCount];
stream.Seek( offset, SeekOrigin.Begin ); // Set offset from Begin of a stream
stream.Read( buffer, 0, bytesCount ); // Read bytesCount from previous set offset
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