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package Hash::Diff;
use strict;
use warnings;
use Carp;
use Hash::Merge;
use base 'Exporter';
use vars qw($VERSION @ISA @EXPORT_OK %EXPORT_TAGS);
$VERSION = 0.010;
@EXPORT_OK = qw( diff left_diff );
sub left_diff {
my ($h1, $h2) = @_;
my $rh = {}; # return_hash
foreach my $k (keys %{$h1}) {
if (not defined $h1->{$k} and exists $h2->{$k} and not defined $h2->{$k}) {
# Empty
}
elsif (ref $h1->{$k} eq 'HASH') {
if (ref $h2->{$k} eq 'HASH') {
my $d = left_diff($h1->{$k}, $h2->{$k});
$rh->{$k} = $d if (%$d);
}
else {
$rh->{$k} = $h1->{$k}
}
}
elsif ((!defined $h1->{$k})||(!defined $h2->{$k})||($h1->{$k} ne $h2->{$k})) {
$rh->{$k} = $h1->{$k}
}
}
return $rh;
}
sub diff {
my ($h1, $h2) = @_;
return Hash::Merge::merge(left_diff($h1,$h2),left_diff($h2,$h1));
}
1;
__END__
=head1 NAME
Hash::Diff - Return difference between two hashes as a hash
=head1 SYNOPSIS
use Hash::Diff qw( diff );
my %a = (
'foo' => 1,
'bar' => { a => 1, b => 1 },
);
my %b = (
'foo' => 2,
'bar' => { a => 1 },
);
my %c = %{ diff( \%a, \%b ) };
# %c = %{ foo => 1, bar => { b => 1} }
=head1 DESCRIPTION
Hash::Diff returns the difference between two hashes as a hash.
=over
=item diff ( <hashref>, <hashref> )
Diffs two hashes. Returns a reference to the new hash.
=item left_diff ( <hashref>, <hashref> )
Returns the values in the left hash that is not, or different from the right hash.
=back
=head1 CAVEATS
This will not handle self-referencing/recursion within hashes well.
This will only handle HASH and SCALAR.
Plans for a future version include incorporate deep recursion protection.
And support for ARRAY.
=head1 BUGS
Sure!
Report here: http://rt.cpan.org/NoAuth/Bugs.html?Dist=Hash::Diff
=head1 AUTHOR
Bjorn-Olav Strand E<lt>bo@startsiden.noE<gt>
=head1 CONTRIBUTOR
Charles McGarvey E<lt>ccm@cpan.orgE<gt>
=head1 COPYRIGHT
Copyright (c) 2010 ABC Startsiden AS. All rights reserved.
This library is free software. You can redistribute it and/or modify it
under the same terms as Perl itself.
=cut
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