use strict;
use warnings;
use File::Spec;

my @arr = (
  { 'path' => '/c/', dir => '/' },
  { 'path' => '/c/a1.mp3', 'file' => 1, 'dir' => '/c' },
  { 'path' => '/c/a2.mp3', 'file' => 1, 'dir' => '/c' },
  { 'path' => '/c/bb/aa1.mp3', 'file' => 1, 'dir' => '/c/bb' },
  { 'path' => '/c/bb/aa2.mp3', 'file' => 1, 'dir' => '/c/bb' },
  { 'path' => '/c/bb/', 'dir' => '/c' },
  { 'path' => '/c/cc/', 'dir' => '/c' },
  { 'path' => '/c/aa/', 'dir' => '/c' }
);

my $TAB_WIDTH=3;
my $FORMAT="%-30s%s\n";

#-----------------------------------------
# The sorting function
#-----------------------------------------
sub parsePathPortably {
  my $hPathInfo = shift;
  my $sPath = $hPathInfo->{path};
  my $bFile = $hPathInfo->{file};
  my ($sVol, $sDir, $sLocal)
    = File::Spec->splitpath($sPath, !$bFile);

  # File::Spec->splitdir assumes $dir is a relative path
  # without this line the first element of @aDirs on *nix is
  # an empty directory (because nothing is before root)

  my $sRelPath = File::Spec->abs2rel($sDir, File::Spec->rootdir());
  my @aDirs =File::Spec->splitdir($sRelPath);

  # get indentation level and local file name
  my $iDepth = scalar(@aDirs);
  unless ($bFile) {
    $iDepth--;
    $sLocal = pop @aDirs;
  }

  # reconstruct the path, but before each directory name
  # segment insert 0x000 and before each file name segment
  # insert 0x001.  It is important to insert something
  # before *all* directory name elements to insure
  # that the "b" segment of /a/b/c and /a/b sort properly
  # 
  # we also insert before file names on the off,off chance
  # that you run into a file system where there is a file
  # name that begins with 0x000. DOS and most *nix systems
  # prohibit 0x000 in file names, but not all
  # - see [Wikipedia://Filename] for a list of OS's where
  # 0x000 does not appear to be in the list of reserved or
  # prohibited characters, among them: OS2, various Mac OS's

 my $k = File::Spec->catpath
    ($sVol, File::Spec->catdir(map{ord(0).$_} @aDirs)
     , ord($bFile ? 1 : 0) . $sLocal);
  return $k => [ $iDepth, $sPath, $sLocal ];
}

#--------------------------------------------------
# Demonstration of how to use the sorting function
#--------------------------------------------------
my $hPaths = { map { parsePathPortably($_) } @arr };
foreach my $k (sort keys %$hPaths) {
  my ($iDepth, $sPath, $sLocal) = @{$hPaths->{$k}};
  my $sIndent = ' ' x ($TAB_WIDTH*$iDepth);
  printf($FORMAT, "$sIndent$sLocal", $sPath);
}

##</code><code>##

c                             /c/
   aa                         /c/aa/
   bb                         /c/bb/
      aa1.mp3                 /c/bb/aa1.mp3
      aa2.mp3                 /c/bb/aa2.mp3
   cc                         /c/cc/
   a1.mp3                     /c/a1.mp3
   a2.mp3                     /c/a2.mp3