Current File : //lib/x86_64-linux-gnu/perl5/5.38/Algorithm/Diff/XS.pm
package Algorithm::Diff::XS;
use 5.006;
use strict;
use warnings;
use vars '$VERSION';
use Algorithm::Diff;
BEGIN {
$VERSION = '0.04';
require XSLoader;
XSLoader::load( __PACKAGE__, $VERSION );
my $code = do {
open my $fh, '<', $INC{'Algorithm/Diff.pm'}
or die "Cannot read $INC{'Algorithm/Diff.pm'}: $!";
local $/;
<$fh>;
};
{
no warnings;
local $@;
$code =~ s/Algorithm::Diff/Algorithm::Diff::XS/g;
$code =~ s/sub LCSidx/sub LCSidx_old/g;
$code = "#line 1 " . __FILE__ . "\n$code";
eval $code;
die $@ if $@;
}
no warnings 'redefine';
sub LCSidx {
my $lcs = Algorithm::Diff::XS->_CREATE_;
my ( @l, @r );
for my $chunk ( $lcs->_LCS_(@_) ) {
push @l, $chunk->[0];
push @r, $chunk->[1];
}
return ( \@l, \@r );
}
}
sub _line_map_ {
my $ctx = shift;
my %lines;
push @{ $lines{ $_[$_] } }, $_ for 0 .. $#_; # values MUST be SvIOK
\%lines;
}
sub _LCS_ {
my ( $ctx, $a, $b ) = @_;
my ( $amin, $amax, $bmin, $bmax ) = ( 0, $#$a, 0, $#$b );
while ( $amin <= $amax and $bmin <= $bmax and $a->[$amin] eq $b->[$bmin] ) {
$amin++;
$bmin++;
}
while ( $amin <= $amax and $bmin <= $bmax and $a->[$amax] eq $b->[$bmax] ) {
$amax--;
$bmax--;
}
my $h =
$ctx->_line_map_( @$b[ $bmin .. $bmax ] ); # line numbers are off by $bmin
return $amin + _core_loop_( $ctx, $a, $amin, $amax, $h ) + ( $#$a - $amax )
unless wantarray;
my @lcs = _core_loop_( $ctx, $a, $amin, $amax, $h );
if ( $bmin > 0 ) {
$_->[1] += $bmin for @lcs; # correct line numbers
}
map( [ $_ => $_ ], 0 .. ( $amin - 1 ) ),
@lcs,
map( [ $_ => ++$bmax ], ( $amax + 1 ) .. $#$a );
}
1;
__END__
=head1 NAME
Algorithm::Diff::XS - Algorithm::Diff with XS core loop
=head1 SYNOPSIS
# Drop-in replacement to Algorithm::Diff, but "compact_diff"
# and C<LCSidx> will run much faster for large data sets.
use Algorithm::Diff::XS qw( compact_diff LCSidx );
=head1 DESCRIPTION
This module is a simple re-packaging of Joe Schaefer's excellent
but not very well-known L<Algorithm::LCS> with a drop-in interface
that simply re-uses the installed version of the L<Algorithm::Diff>
module.
Note that only the C<LCSidx> function is optimized in XS at the
moment, which means only C<compact_diff> will get significantly
faster for large data sets, while C<diff> and C<sdiff> will run
in identical speed as C<Algorithm::Diff>.
=head1 BENCHMARK
Rate Algorithm::Diff Algorithm::Diff::XS
Algorithm::Diff 14.7/s -- -98%
Algorithm::Diff::XS 806/s 5402% --
The benchmarking script is as below:
my @data = ([qw/a b d/ x 50], [qw/b a d c/ x 50]);
cmpthese( 500, {
'Algorithm::Diff' => sub {
Algorithm::Diff::compact_diff(@data)
},
'Algorithm::Diff::XS' => sub {
Algorithm::Diff::XS::compact_diff(@data)
},
});
=head1 SEE ALSO
L<Algorithm::Diff>, L<Algorithm::LCS>.
=head1 AUTHORS
Audrey Tang E<lt>cpan@audreyt.orgE<gt>
=head1 COPYRIGHT
Copyright 2008 by Audrey Tang E<lt>cpan@audreyt.orgE<gt>.
Contains derived code copyrighted 2003 by Joe Schaefer,
E<lt>joe+cpan@sunstarsys.comE<gt>.
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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