package path;
use strict;
use warnings;

my $sep;
my $sep_not;
BEGIN {
  if($^O=~/linux|os2|vms|unix|epoc/i)
  {
    $sep=qr!/!;
    $sep_not=qr![^/]!;
  }
  elsif($^O=~/win/i)
  {
    $sep=qr/\\/;
    $sep_not=qr/[^\\]/;
  }
  elsif($^O=~/cygwin/i)
  {
    $sep=qr'[/\\]';
    $sep_not=qr'[^/\\]';
  }
  elsif($^O=~/mac/i)
  {
    $sep=qr!:!;
    $sep_not=qr![^:]!;
  }
  else
  {
    $sep=qr([/\\:]);
    $sep_not=qr([^/\\:]);
  }
}

sub clean($)
{
  my $path=shift;
  1 while( $path=~s!$sep($sep)!$1!gs );
  1 while( $path=~s!(^|$sep)\.$sep!$1!s );
  1 while( $path=~s!$sep$sep_not*$sep\.\.!!s );
  1 while( $path=~s!^$sep\.\.?(?=$sep)!!s );
  1 while( $path=~s!^\.$sep!!s );
  1 while( $path=~s!($sep)\.$!$1!s );
  return $path;
}

sub strip($)
{
  my $path=shift;
  1 while( $path=~s!^\.\.?$sep!!s );
  1 while( $path=~s!(^|$sep)\.\.?(?=$sep|$)!$1!s );
  1 while( $path=~s!$sep($sep)!$1!gs );
  return $path;
}

1;