Encode::MIME::Header clean up

Encode.pm

@@ -15,7 +15,7 @@ use Exporter 5.57 'import';
 
 our @EXPORT = qw(
   decode  decode_utf8  encode  encode_utf8 str2bytes bytes2str
-  encodings  find_encoding clone_encoding
+  encodings  find_encoding find_mime_encoding clone_encoding
 );
 our @FB_FLAGS = qw(
   DIE_ON_ERR WARN_ON_ERR RETURN_ON_ERR LEAVE_SRC
@@ -102,6 +102,8 @@ sub define_encoding {
 sub getEncoding {
     my ( $class, $name, $skip_external ) = @_;
 
+    defined($name) or return;
+
     $name =~ s/\s+//g; # https://rt.cpan.org/Ticket/Display.html?id=65796
 
     ref($name) && $name->can('renew') and return $name;
@@ -130,6 +132,14 @@ sub find_encoding($;$) {
     return __PACKAGE__->getEncoding( $name, $skip_external );
 }
 
+sub find_mime_encoding($;$) {
+    my ( $mime_name, $skip_external ) = @_;
+    eval { require Encode::MIME::Name; };
+    $@ and return;
+    my $name = Encode::MIME::Name::get_encode_name( $mime_name );
+    return find_encoding( $name, $skip_external );
+}
+
 sub resolve_alias($) {
     my $obj = find_encoding(shift);
     defined $obj and return $obj->name;
@@ -577,6 +587,20 @@ name of the encoding object.
 
 See L<Encode::Encoding> for details.
 
+=head3 find_mime_encoding
+
+  [$obj =] find_mime_encoding(MIME_ENCODING)
+
+Returns the I<encoding object> corresponding to I<MIME_ENCODING>.  Acts
+same as C<find_encoding()> but C<mime_name()> of returned object must
+match to I<MIME_ENCODING>.  So as opposite of C<find_encoding()>
+canonical names and aliases are not used when searching for object.
+
+    find_mime_encoding("utf8"); # returns undef because "utf8" is not valid I<MIME_ENCODING>
+    find_mime_encoding("utf-8"); # returns encode object "utf-8-strict"
+    find_mime_encoding("UTF-8"); # same as "utf-8" because I<MIME_ENCODING> is case insensitive
+    find_mime_encoding("utf-8-strict"); returns undef because "utf-8-strict" is not valid I<MIME_ENCODING>
+
 =head3 from_to
 
   [$length =] from_to($octets, FROM_ENC, TO_ENC [, CHECK])