A1,A2,A3,A4
B1,B2,B3,B4
1,Just some data,c29tZSBzdHJpbmc=
C1,C2,C3,C4
D1,VGhpcyBpcyBkZWNvZGVkIQ==,D3,D4,GibberishdlkfjsDKjdlslksJAoiasosaSDSD==

##</code><code>##

#csvDecode.pl VERSION 1
#Written by Andrew Hoyt
#Takes LogData from the MSS Portal and decodes the base64 characters (assuming there is any base64 to be decoded, and if so, that it's in column eleven).


#!/usr/bin/perl
use strict;
use warnings;
use Text::CSV;
use MIME::Base64;

my $i=0;

my @columns;
my @cleanData;
my @input;

my $file = 'data.csv';

my $csv = Text::CSV->new();

open (CSV, "<", $file) or die $!;


my $string;


while (<CSV>) {
	
	if ($csv->parse($_)) {
		@columns = $csv->fields();
		#my $numCols = $#columns;
		#print "($numCols)\n";

	} else {
		my $err = $csv->error_input;
		print "Failed to parse line: $err";
	}
	
	foreach (@columns){
	$_ = check($_);
	$cleanData[$i] = $_;
	$i++;
	print $_;
	}
	
	print "\n";

} 	

close CSV;

open (MYFILE, ">", "output.csv") or die $!;

	foreach (@cleanData){
		print MYFILE "$_,";
	
	#print MYFILE "\n";
	}

#print MYFILE "\n";
close MYFILE;

sub check{

my $col = shift;

$col = decode_base64($col) if m{
            ^
            (?: [A-Za-z0-9+/]{4} )*
            (?:
                [A-Za-z0-9+/]{2} [AEIMQUYcgkosw048] =
            |
                [A-Za-z0-9+/] [AQgw] ==
            )?
            $
        }x;


return $col;
}

##</code><code>##

A1,A2,A3,A4,B1,B2,B3,B4,1,Just some data,some string,C1,C2,C3,C4,D1,This is decoded!,D3,D4,GibberishdlkfjsDKjdlslksJAoiasosaSDSD==,