#!/usr/bin/perl
use strict;
use File::Find;
use Data::Dumper;

my $dir_list;
# count of { file_row => [...] } entries inside
# dir_row array. (err.. simply dir_row array's size).
my $dir_row_count = 0;
my $file_count = 0;
# number of files in a row..
my $file_split_count = 5; 
# previous directory
my $prev_dir; 

find(\&wanted, 'data');

print Dumper($dir_list);

### SUBS

sub wanted { 
  $DB::single = 1;
  unless ($prev_dir eq $File::Find::dir) {
    $prev_dir = $File::Find::dir;
    # got a new directory
    push @$dir_list, { dir => $File::Find::dir, dir_row => [] };
  }

  if (-f $_) {
    unless ($file_count % $file_split_count) {
      # add another file row if maximum number of files
      # allowed in a row has been exceeded.
      push @{$dir_list->[scalar @$dir_list - 1]{dir_row}}, { file_row => [] };
    }

    # add file to the file row...
    push @{$dir_list->[scalar @$dir_list - 1]{dir_row}[$dir_row_count]{file_row}}, 
      { filename => $File::Find::name };
    $dir_row_count++; 
    $file_count++;
  }
}