package RangedHash;

sub TIEHASH { bless({}, shift); }
# the key should be the start point of the range
sub STORE { $_[0]->{$_[1]} = $_[2]; }

sub FETCH {
	my ($self, $point) = @_;
	my $cursor = 0;
	foreach ( sort keys %$self ) {
		return $self->{$cursor} if ( $point >= $cursor && $point < $_ );
		$cursor = $_;
	}
	return $self->{$cursor}
}

package main;

my %ranged_hash;
tie(%ranged_hash, "RangedHash");
$ranged_hash{0} = 'foo';
$ranged_hash{10} = 'bar';
$ranged_hash{20} = 'qux';
$range_hash{3}; # 'foo'
$range_hash{14}; # 'bar'
$range_hash{27}; # 'qux'