From: Mark Firestone <hash_bang@...>
Date: 2005-01-09T09:10:38+09:00
Subject: file io question

I'm writing a fido mail tosser for my ruby bbs.  (A thankless task that
is far worse than I ever imagined when I started.) and I have a problem
I don't understand.

To read the packets (the header in this case, I have to do the
following, is it is stored in an odd way.  Here's a snippet of the file
header...

PP�
 (and lots of other low ascii characters...)

So, I read it like this, suck in a bunch of it in a buffer...

buffer   = happy.read(0x3a)

orgnode	= (buffer[0x01] << 8) + buffer[0x00]
destnode  	= (buffer[0x03] << 8) + buffer[0x02]
orgnet	= (buffer[0x15] << 8) + buffer[0x14]
destnet	= (buffer[0x17] << 8) + buffer[0x16]
orgzone	= (buffer[0x23] << 8) + buffer[0x22]
destzone	= (buffer[0x25] << 8) + buffer[0x24]

and so on.  This works great, we get the right answer...

if I try to reverse this and write stuff, it doesn't work.  For
example...

happy = File.new("#{path}", File::CREAT|File::APPEND|File::RDWR, 0644)

buffer = []
   
   buffer[0x00] = (f_hdr.orgnode & 0x00ff)
   buffer[0x01] = ((f_hdr.orgnode & 0xff00) >> 8)
   buffer[0x02] = (f_hdr.destnode & 0x00ff).chr
   buffer[0x03] = ((f_hdr.destnode & 0xff00) >> 8)
   buffer[0x04] = ((f_hdr.year + 1900) & 0x00ff)
   buffer[0x05] = (((f_hdr.year + 1900) & 0xff00) >> 8)
   buffer[0x06] = f_hdr.month
   buffer[0x08] = f_hdr.day
   buffer[0x0a] = f_hdr.hour

and so on and then...

happy.write buffer

I get a string of numbers.  If I try to put .chr at the end, the first
two values read ok, then it goes haywire.  I don't think I understand
what I'm doing.  Can anyone point me in the right direction? 

Thanks!

Mark