Greetings.

I'm seeking wisdom from the monastery on handling creation of an array of bytes. I've done some research and it appears that I can use the pack command, but I am at a loss on how to obtain the results I seek.

I need to construct a "token" formatted as: 

bytes 0 - 3: unsigned 32 bit representation of seconds since the epoch
bytes 4 - 7: unsigned 32 bit number (this represents an employee id)
byte 8: A check byte computed from the exclusive-or ("xor") of all the
+ previous bytes

[download]

I understand I can get the seconds since the epoch using time(), and I have the employee id as a 9 digit number - how do I format these into the above token and how do I create the xor check byte?

Any and all assistance is greatly appreciated.

In reply to packing into a byte token by dulac

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":


  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.