FML::Checksum -> Mail::Message::Checksum

1 files changed, 245 insertions, 0 deletions

diff --git a/fml/lib/Mail/Message/Checksum.pm b/fml/lib/Mail/Message/Checksum.pm
new file mode 100644
index 00000000..f5d96d94
--- /dev/null
+++ b/fml/lib/Mail/Message/Checksum.pm
@@ -0,0 +1,245 @@
+#-*- perl -*-
+#
+#  Copyright (C) 2001 Ken'ichi Fukamachi
+#   All rights reserved. This program is free software; you can
+#   redistribute it and/or modify it under the same terms as Perl itself.
+#
+# $FML: Checksum.pm,v 1.13 2001/12/22 09:21:00 fukachan Exp $
+#
+
+package Mail::Message::Checksum;
+use strict;
+use vars qw(@ISA @EXPORT @EXPORT_OK $AUTOLOAD);
+use Carp;
+use FML::Log qw(Log LogWarn LogError);
+
+=head1 NAME
+
+Mail::Message::Checksum - utilities for check sum
+
+=head1 SYNOPSIS
+
+   use Mail::Message::Checksum;
+   $cksum  = new Mail::Message::Checksum;
+   $md5sum = $cksum->md5( \$string );
+
+=head1 METHODS
+
+=head2 C<new()>
+
+the constructor.
+It checks we can use MD5 perl module or we need to use external programs
+such as C<md5>, C<cksum>, et.al.
+
+=cut
+
+
+sub new
+{
+    my ($self, $args) = @_;
+    my ($type) = ref($self) || $self;
+    my $me     = {};
+
+    _init($me, $args);
+
+    return bless $me, $type;
+}
+
+
+sub _init
+{
+    my ($self, $args) = @_;
+
+    if (defined $args->{ program }) {
+	$self->{ _program } = $args->{ program };
+    }
+
+    my $pkg = 'MD5';
+    eval qq{ require $pkg; $pkg->import();};
+
+    unless ($@) {
+	$self->{ _type } = 'native';
+    }
+    else {
+	eval qq{ require File::Utils; import File::Utils qw(search_program);};
+	my $prog = search_program('md5') || search_program('md5sum');
+	if (defined $prog) {
+	    $self->{ _program } = $prog;
+	}
+    }
+}
+
+
+
+=head2 C<md5(\$string)>
+
+return the md5 checksum of the given string C<$string>.
+
+=cut
+
+
+sub md5
+{
+    my ($self, $r_data) = @_;
+
+    if ($self->{ _type } eq 'native') {
+	$self->_md5_native($r_data);
+    }
+    else {
+	$self->_md5_by_program($r_data);
+    }
+
+}
+
+
+sub _md5_native
+{
+    my ($self, $r_data) = @_;
+    my ($buf, $p, $pe);
+
+    $pe = length($$r_data);
+
+    my $md5;
+    eval q{ $md5 = new MD5;};
+    $md5->reset();
+
+    $p = 0;
+    while (1) {
+	last if $p > $pe;
+	$_  = substr($$r_data, $p, 128);
+	$p += 128;
+	$md5->add($_);
+    }
+
+    $md5->hexdigest();
+}
+
+
+sub _md5_by_program
+{
+    my ($self, $r_data) = @_;
+
+    if (defined $self->{ _program }) {
+	my $program = $self->{ _program };
+
+	use FileHandle;
+	my ($rh, $wh) = FileHandle::pipe;
+
+	eval qq{ require IPC::Open2; IPC::Open2->import();};
+	my $pid = open2($rh, $wh, $self->{ _program });
+	if (defined $pid) {
+	    print $wh $$r_data;
+	    close($wh);
+	    my $cksum = 0;
+	    sysread($rh, $cksum, 1024);
+	    $cksum =~ s/[\s\n]*$//;
+	    close($rh);
+	    return $cksum if $cksum;
+	}
+    }
+
+    undef;
+}
+
+
+=head2 C<cksum1($file)>
+
+C<not implemented>.
+
+This is a 16-bit checksum. The algorithm used by historic BSD systems
+as the sum(1) algorithm and by historic AT&T System V UNIX systems as
+the sum algorithm when using the C<-r> option.
+
+=head2 C<cksum2($file)>
+
+return the traditional checksum of the given C<$file>.
+
+This is a 32-bit checksum. The algorithm used by historic AT&T System
+V UNIX systems as the default sum algorithm.
+
+See POSIX 1003.2 for more details.
+
+=cut
+
+
+sub cksum2
+{
+    my ($self, $f) = @_;
+    my ($crc, $total, $nr, $buf, $r);
+
+    $crc = $total = 0;
+    if (open($f, $f)) {
+        while (($nr = sysread($f, $buf, 1024)) > 0) {
+            my ($i) = 0;
+            $total += $nr;
+
+            for ($i = 0; $i < $nr; $i++) {
+                $r = substr($buf, $i, 1);
+                $crc += ord($r);
+            }
+        }
+        close($f);
+        $crc = ($crc & 0xffff) + ($crc >> 16);
+        $crc = ($crc & 0xffff) + ($crc >> 16);
+    }
+    else {
+        Log("ERROR: no such file $f");
+    }
+
+    ($crc, $total);
+}
+
+
+=head2 C<crc($file)>
+
+C<not implemented>.
+
+The default CRC used is based on the polynomial used for CRC error
+checking in the networking standard ISO 8802-3:1989 The CRC checksum
+encoding is defined by the generating polynomial:
+
+  G(x) = x^32 + x^26 + x^23 + x^22 + x^16 + x^12 +
+         x^11 + x^10 + x^8 + x^7 + x^5 + x^4 + x^2 + x + 1
+
+Mathematically, the CRC value corresponding to a given file is defined
+by the following procedure:
+
+The n bits to be evaluated are considered to be the coefficients of
+a mod 2 polynomial M(x) of degree n-1.  These n bits are the bits
+from the file, with the most significant bit being the most signif-
+icant bit of the first octet of the file and the last bit being the
+least significant bit of the last octet, padded with zero bits (if
+necessary) to achieve an integral number of octets, followed by one
+or more octets representing the length of the file as a binary val-
+ue, least significant octet first.  The smallest number of octets
+capable of representing this integer are used.
+
+M(x) is multiplied by x^32 (i.e., shifted left 32 bits) and divided
+by G(x) using mod 2 division, producing a remainder R(x) of degree
+<= 31.
+
+The coefficients of R(x) are considered to be a 32-bit sequence.
+
+The bit sequence is complemented and the result is the CRC.
+
+=head1 AUTHOR
+
+Ken'ichi Fukamachi
+
+=head1 COPYRIGHT
+
+Copyright (C) 2001 Ken'ichi Fukamachi
+
+All rights reserved. This program is free software; you can
+redistribute it and/or modify it under the same terms as Perl itself.
+
+=head1 HISTORY
+
+Mail::Message::Checksum appeared in fml5 mailing list driver package.
+See C<http://www.fml.org/> for more details.
+
+Algorithm used here is based on NetBSD cksum library (C program).
+
+=cut
+
+1;