>(1) make the FileStream a class property
>(2) add a byte[] Buffer as a class property

I assume the usage of propery would be to avoid declaring the types at each request. Is that correct?

>(3) Add a method IsByteEqual ( int fileOffset, int value)
>

>if ( fileOffset +1 > length of the buffer )
>    read a buffer starting a file offset 0, size = fileOffset +1 rounded to a multiple of 4 k ( or 16 k)
>
>return buffer[fileOffset ] ==value
>

>You will need to clear the buffer each time you open a new file
>
>(4) sample
>

>if( IsByteEqual(0, 0x45) andalso IsByteEqual(1, 0x64) )
>  filetype = something
>else if if( IsByteEqual(0, 0c80) andalso IsByteEqual(24, 0x88) )
> filetype = somethingelse
>.....
>else
> filetype = undefined
>

Thanks, I will see about seeking only at the proper locations.

However, some advanced logic, such as determining a zip file type requires more processing and for particular ones like that, I am not sure if a seek would suffice.