Add hash methods to compare

lib/Data/Layered.pm

@@ -7,7 +7,7 @@ use Exporter;
 use vars qw(@ISA @EXPORT_OK);
 
 @ISA = qw(Exporter);
-@EXPORT_OK = qw(layered_get);
+@EXPORT_OK = qw(layered_get layered_get2 layered_get3);
 
 =encoding utf-8
 
@@ -109,6 +109,35 @@ sub layered_get {
     return \@results;
 }
 
+sub layered_get2 {
+    my ($class) = @_;
+    shift() unless ref $class;
+    my ($keys, $layers) = @_;
+
+    ## degenerated cases
+    return {} unless $keys;
+    return $keys unless $layers;
+
+    my %results   = ();
+    my @need_keys = @$keys;
+
+    for my $layer (@$layers) {
+        $layer->(\@need_keys, \%results);
+
+        # keys which have been resolved will have a key in %results
+        # the rest will need to be attempted at the next layer
+        @need_keys = grep { ! exists $results{$_} } @need_keys;
+    }
+
+    return \%results;
+}
+
+sub layered_get3 {
+    my $keys = $_[0];
+    my $res = layered_get2(@_);
+    return [ map { $res->{$_} } @$keys ];
+}
+
 =head1 AUTHOR
 
 Yann Kerherve E<lt>yannk@cpan.orgE<gt>

t/02_bench.t

@@ -0,0 +1,51 @@
+use Find::Lib '../lib';
+use strict;
+use warnings;
+use Benchmark 'timethese';
+
+use Data::Layered 'layered_get', 'layered_get2', 'layered_get3';
+
+## define some caches
+my $L1 = {};
+my $L2 = {};
+my $keys = [];
+for (1 .. 50000) {
+    $L1->{ int rand (100000) } = int rand (1000);
+    $L2->{ int rand (100000) } = int rand (1000);
+    push @$keys, int rand (100000);
+}
+my %seen;
+@$keys = grep { ! $seen{$_}++ } @$keys;
+
+my $l1 = sub { [ @$L1{ @{$_[0]} } ] };
+my $l2 = sub { [ @$L2{ @{$_[0]} } ] };
+
+my $l1_2 = sub {
+    my ($keys, $res) = @_;
+    for my $k (@$keys) {
+        $res->{$k} = $L1->{$k};
+    }
+};
+
+my $l2_2 = sub {
+    my ($keys, $res) = @_;
+    for my $k (@$keys) {
+        $res->{$k} = $L2->{$k};
+    }
+};
+
+timethese 5, {
+    layered_get => sub {
+        my $res = layered_get( $keys, [ $l1, $l2 ]);
+        #warn scalar grep { defined } @$res;
+    },
+    layered_get2 => sub {
+        my $res = layered_get2( $keys, [ $l1_2, $l2_2 ]);
+        #warn scalar grep { defined $res->{$_} } keys %$res;
+    },
+
+    layered_get3 => sub {
+        my $res = layered_get3( $keys, [ $l1_2, $l2_2 ]);
+        #warn scalar grep { defined $res->{$_} } keys %$res;
+    },
+};