The idea is quite simple :
Just split up the string at every 1 and then count how long the sequences of zeroes are that you got back. As a one-liner, this looks like

perl -e "print length,qq(\n) for split /1/,'10000000000001000000000000
+00100';"
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As a full-blown Perl program, this would look somewhat like this :

#!/usr/bin/perl -w
use strict;

while (<DATA>) {
  my @bits = split /1/;
  # every string starts with a 1, so 
  # pop the first zero off of @bits
  pop @bits; 
  print join( ",", @bits ), "\n";
};
__DATA__
1000000000000100000000000000100
[download]

perl -MHTTP::Daemon -MHTTP::Response -MLWP::Simple -e ' ;    # The  
$d = new HTTP::Daemon and fork and getprint $d->url and exit;#spider
($c = $d->accept())->get_request(); $c->send_response( new   #in the
HTTP::Response(200,$_,$_,qq(Just another Perl hacker\n))); ' #  web
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