I take it back!

Having looked in more detail at the specification this morning, I see why you're having problems working out how to do this.

This is one of those really nasty pieces of mainframe/COBOL-esque encoding, that requires BCD math on a fixed length BCD field. (COBOL: PIC 9(13) COMP).

Perl's pack & unpack don't have anything to handle this directly, and even on a 64-bit machine, integer math simply isn't capable of handling 13-byte numbers.

One way might be to drop into Inline::C and inline assembler (or Inline::Asm ) and use the vestigal BCD opcodes. (Though MS 64-bit compilers don't support inline assembler.)

There are also some weird x64 opcodes that treat an 80-bit floating point register as a 17 digit BCD value that might be pressed into service for this.

Perhaps the easiest and most portable way would be to use Math::BigInt to do the math; as_hex() to get it out of BigInt format; and then pack 'H26' to creat the binary string.

Or download the USPS libraries and link them from XS.

I think that the BigInt method would be easiest. Let us know if you need help with that?

Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.
"Science is about questioning the status quo. Questioning authority".
In the absence of evidence, opinion is indistinguishable from prejudice.
RIP an inspiration; A true Folk's Guy

In reply to Re: USPS Intelligent Barcode - binary data manipulations by BrowserUk
in thread USPS Intelligent Barcode - binary data manipulations by elfpen

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.