package Number;

use strict;
use warnings;
use IO::File;
use Carp;
use Fcntl ':flock';
use Tie::Scalar;
our @ISA = qw(Tie::StdScalar);

# VARs intern
my $fh = new IO::File;
my %rep = ();            # Repository
my $repkey = undef;      # Pepository Key

# Constructor
sub TIESCALAR{
	my $class = shift;

	my %args = (
		-file => undef,
		-key  => undef,
		-auto => 1,
		@_
	);

	croak "No file, use -file in args!" if not defined $args{-file};
	croak "No key, use -key in args!" if not defined $args{-key};

	deserialize($args{-file}) or return;
	$repkey = $args{-key} || '_default';
	$rep{$repkey} ||= 0;
	$rep{$repkey}++ if $args{-auto} == 1;
	my $nr = $rep{$repkey};
	return bless \$nr, $class;
}

# hash to file
sub serialize{
	if(defined $fh){
		truncate $fh, 0;
		seek $fh, 0, 0;
		while(my ($k, $v) = each %rep){
			print $fh pack("N", length $k).$k.pack("N", $v);
		}
	}
}

# hash from $file
sub deserialize{
	my $file = shift;
	$fh->open($file, O_CREAT|O_BINARY|O_RDWR) or return;
	flock($fh, LOCK_EX) or die "Your system does not support flock()!";
	binmode $fh, ':raw';
	seek $fh, 0, 0;
	my ($buffer, $key, $klen, $number) = (undef, undef, undef, undef);
	while(read $fh, $buffer, 4){
		$klen = unpack "N", $buffer;
		read $fh, $key, $klen;
		read $fh, $buffer, 4;
		$rep{$key} = unpack "N", $buffer;
	}
	return 1;
}


sub DESTROY{
	serialize();
	undef $fh;
}

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1; ########################################################################
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