package File::Compare;use 5.005_64;use strict;our($VERSION, @ISA, @EXPORT, @EXPORT_OK, $Too_Big);require Exporter;use Carp;$VERSION = '1.1002';@ISA = qw(Exporter);@EXPORT = qw(compare);@EXPORT_OK = qw(cmp compare_text);$Too_Big = 1024 * 1024 * 2;sub VERSION {    # Version of File::Compare    return $File::Compare::VERSION;}sub compare {    croak("Usage: compare( file1, file2 [, buffersize]) ")      unless(@_ == 2 || @_ == 3);    my ($from,$to,$size) = @_;    my $text_mode = defined($size) && (ref($size) eq 'CODE' || $size < 0);    my ($fromsize,$closefrom,$closeto);    local (*FROM, *TO);    croak("from undefined") unless (defined $from);    croak("to undefined") unless (defined $to);    if (ref($from) &&         (UNIVERSAL::isa($from,'GLOB') || UNIVERSAL::isa($from,'IO::Handle'))) {	*FROM = *$from;    } elsif (ref(\$from) eq 'GLOB') {	*FROM = $from;    } else {	open(FROM,"<$from") or goto fail_open1;	unless ($text_mode) {	    binmode FROM;	    $fromsize = -s FROM;	}	$closefrom = 1;    }    if (ref($to) &&        (UNIVERSAL::isa($to,'GLOB') || UNIVERSAL::isa($to,'IO::Handle'))) {	*TO = *$to;    } elsif (ref(\$to) eq 'GLOB') {	*TO = $to;    } else {	open(TO,"<$to") or goto fail_open2;	binmode TO unless $text_mode;	$closeto = 1;    }    if (!$text_mode && $closefrom && $closeto) {	# If both are opened files we know they differ if their size differ	goto fail_inner if $fromsize != -s TO;    }    if ($text_mode) {	local $/ = "\n";	my ($fline,$tline);	while (defined($fline = <FROM>)) {	    goto fail_inner unless defined($tline = <TO>);	    if (ref $size) {		# $size contains ref to comparison function		goto fail_inner if &$size($fline, $tline);	    } else {		goto fail_inner if $fline ne $tline;	    }	}	goto fail_inner if defined($tline = <TO>);    }    else {	unless (defined($size) && $size > 0) {	    $size = $fromsize || -s TO || 0;	    $size = 1024 if $size < 512;	    $size = $Too_Big if $size > $Too_Big;	}	my ($fr,$tr,$fbuf,$tbuf);	$fbuf = $tbuf = '';	while(defined($fr = read(FROM,$fbuf,$size)) && $fr > 0) {	    unless (defined($tr = read(TO,$tbuf,$fr)) && $tbuf eq $fbuf) {		goto fail_inner;	    }	}	goto fail_inner if defined($tr = read(TO,$tbuf,$size)) && $tr > 0;    }    close(TO) || goto fail_open2 if $closeto;    close(FROM) || goto fail_open1 if $closefrom;    return 0;      # All of these contortions try to preserve error messages...  fail_inner:    close(TO) || goto fail_open2 if $closeto;    close(FROM) || goto fail_open1 if $closefrom;    return 1;  fail_open2:    if ($closefrom) {	my $status = $!;	$! = 0;	close FROM;	$! = $status unless $!;    }  fail_open1:    return -1;}sub cmp;*cmp = \&compare;sub compare_text {    my ($from,$to,$cmp) = @_;    croak("Usage: compare_text( file1, file2 [, cmp-function])")	unless @_ == 2 || @_ == 3;    croak("Third arg to compare_text() function must be a code reference")	if @_ == 3 && ref($cmp) ne 'CODE';    # Using a negative buffer size puts compare into text_mode too    $cmp = -1 unless defined $cmp;    compare($from, $to, $cmp);}1;__END__=head1 NAMEFile::Compare - Compare files or filehandles=head1 SYNOPSIS  	use File::Compare;	if (compare("file1","file2") == 0) {	    print "They're equal\n";	}=head1 DESCRIPTIONThe File::Compare::compare function compares the contents of twosources, each of which can be a file or a file handle.  It is exportedfrom File::Compare by default.File::Compare::cmp is a synonym for File::Compare::compare.  It isexported from File::Compare only by request.File::Compare::compare_text does a line by line comparison of the twofiles. It stops as soon as a difference is detected. compare_text()accepts an optional third argument: This must be a CODE reference toa line comparison function, which returns 0 when both lines are consideredequal. For example:    compare_text($file1, $file2)is basically equivalent to    compare_text($file1, $file2, sub {$_[0] ne $_[1]} )=head1 RETURNFile::Compare::compare return 0 if the files are equal, 1 if thefiles are unequal, or -1 if an error was encountered.=head1 AUTHORFile::Compare was written by Nick Ing-Simmons.Its original documentation was written by Chip Salzenberg.=cut