—

              
package File::Compare 1.1008;
use v5.12;
use warnings;
use Exporter 'import';
our @EXPORT = qw(compare);
our @EXPORT_OK = qw(cmp compare_text);
our $Too_Big = 1024 * 1024 * 2;
sub croak {
    require Carp;
    goto &Carp::croak;
}
sub compare {
    croak("Usage: compare( file1, file2 [, buffersize]) ")
      unless(@_ == 2 || @_ == 3);
    my ($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
    compare($from, $to, $cmp // -1);
}
1;
__END__
HideShow 43 lines of Pod
=head1 NAME
File::Compare - Compare files or filehandles
=head1 SYNOPSIS
        use File::Compare;
        if (compare("file1", "file2") == 0) {
            print "They're equal\n";
        }
=head1 DESCRIPTION
The C<File::Compare::compare> function compares the contents of two
sources, each of which can be a file or a file handle.  It is exported
from C<File::Compare> by default.
C<File::Compare::cmp> is a synonym for C<File::Compare::compare>.  It is
exported from C<File::Compare> only by request.
C<File::Compare::compare_text> does a line by line comparison of the two
files. It stops as soon as a difference is detected. C<compare_text()>
accepts an optional third argument: This must be a CODE reference to
a line comparison function, which returns C<0> when both lines are considered
equal. For example:
    compare_text($file1, $file2)
is basically equivalent to
    compare_text($file1, $file2, sub {$_[0] ne $_[1]} )
=head1 RETURN
C<File::Compare::compare> and its sibling functions return C<0> if the files
are equal, C<1> if the files are unequal, or C<-1> if an error was encountered.
=head1 AUTHOR
C<File::Compare> was written by Nick Ing-Simmons.
Its original documentation was written by Chip Salzenberg.