--- amavisd.orig	2006-01-28 15:31:53.000000000 +0900
+++ amavisd	2006-05-16 01:07:03.000000000 +0900
@@ -1392,6 +1392,7 @@
 
 # A wrapper for Encode::encode, avoiding a bug in Perl 5.8.0 which causes
 # Encode::encode to loop and fill memory when given a tainted string
+use Encode::Guess;
 sub safe_encode($$;$) {
   if (!$unicode_aware) { $_[1] }  # just return the second argument
   else {
@@ -1399,7 +1400,12 @@
     $check = 0  if !defined($check);
     # taintedness of the string, with UTF-8 flag unconditionally off
     my($taint) = Encode::encode('ascii',substr($str,0,0));
-    $taint . Encode::encode($encoding,untaint($str),$check);  # preserve taint
+    my $enc = guess_encoding(untaint($str), qw/euc-jp shiftjis 7bit-jis/);
+    if (ref($enc)){
+      $taint . Encode::encode($encoding,$enc->decode(untaint($str)),$check);  # preserve taint
+    }else{
+      $taint . Encode::encode($encoding,untaint($str),$check);  # preserve taint
+    }
   }
 }