Re: How to use Convert::ASN1 ?

If the data was in ASN.1 format you would need an ASN.1 grammar to parse it. However, that doesn't look like ASN.1 data.

Here is a simple (non-ASN.1) decoder based on your specification:

    #!/usr/bin/perl -w

    use strict;

    my $message = pack 'H*', join '', qw(
        9f a1 0b 00 9f a1 0b 00 9f be 00 02 00 15 9f be
        01 81 0f 01 55 18 f3 0b 24 99 20 10 00 10 00 00
        00 01 9f be 19 81 09 00 01 10 60 18 00 38 38 11
        9f be 1b 08 02 01 10 ff ff ff ff ff a1 06 82 04
        04 00 00 00
    );

    _unpack_message($message);

    sub _unpack_message {

        my $message = shift;

        print "Tag     Length  Data\n";

        while ($message) {
            my $tag     = unpack 'H6', substr $message, 0, 3, '';
            my $length  = unpack 'C',  substr $message, 0, 1, '';

            if ($length == 0x81) {
                $length = unpack 'C',  substr $message, 0, 1, '';
            }

            my $template = 'H' . $length * 2;
            my $data     = unpack $template, substr $message, 0, $leng
+th, '';

            printf "%s  %-6d  %s\n", $tag, $length, $data;
        }
    }

    __END__
    Prints:

    Tag     Length  Data
    9fa10b  0       
    9fa10b  0       
    9fbe00  2       0015
    9fbe01  15      015518f30b24992010001000000001
    9fbe19  9       000110601800383811
    9fbe1b  8       020110ffffffffff
    a10682  4       04000000
[download]

--
John.

Comment on Re: How to use Convert::ASN1 ? Download Code

Replies are listed 'Best First'.

Re^2: How to use Convert::ASN1 ?
by bh_perl (Monk) on Jun 25, 2010 at 04:46 UTC

#!/usr/bin/perl -w

use Cwd;
use warnings;
use strict;
use Getopt::Long;

use constant FILEHDR => 4;
use constant CDRLEN  => 286;

my ($trace, $help, $infile);
my $swap = '';
my $indir  = getcwd;
my $outdir = getcwd;

GetOptions (
    "h|help"    => \$help,
    "filename|f=s"    => \$infile,
    "swap|s"    => \$swap,
    "input|i=s"    => \$indir,
    "output|o=s"    => \$outdir,
    "trace|t"    => \$trace
) or usage();


sub usage {
    exit;
}

my $outfile = $infile;
my $data;

if ($infile) {
    #open (OUTPUT, ">$outdir/$outfile");
    open (DATA, "$indir/$infile");
    binmode DATA;
    
    while ($data = <DATA>) {
        my $tag    = unpack "H2", substr $data,0,1,'';
        my $length = unpack "C", substr $data,0,1,'';

        if ($length == 0x81) {
            $length = unpack "C", substr $data,0,1,'';
        }

                # Problem is here.. data not substr correctly
        my $template = 'H' . $length*2;
        my $rec      = unpack $template, substr $data,0,$length,'';

        printf ("RECORD TAG    : %s\n", $tag);
        printf ("RECORD LENGTH : %s\n", $length);
        printf ("RECORD        : %s\n", $rec);
    }

    close(DATA);
    #close(OUTPUT);
}
[download]

84 47 00 0c 00 00 11 0a 03 50 35 04 00 64 0a 04
16 12 00 1e 00 1d 00 00 65 09 08 54 52 03 2f 82
05 10 00 02 6e 06 0b a8 53 11 67 00 00 00 7a 7f
00 69 4a 42 47 48 4a 41 0c 00 6a 53 54 4d 44 54
4f 1c 00 66 04 00 00
[download]

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