gistfile1.txt

diff --git a/lib/Encode/MIME/Header.pm b/lib/Encode/MIME/Header.pm
index 5f209b2..d61b589 100644
--- a/lib/Encode/MIME/Header.pm
+++ b/lib/Encode/MIME/Header.pm
@@ -61,10 +61,10 @@ sub decode($$;$) {
     }{
         if      (uc($2) eq 'B'){
             $obj->{decode_b} or croak qq(MIME "B" unsupported);
-            decode_b($1, $3, $chk);
+            $obj->decode_b($1, $3, $chk);
         } elsif (uc($2) eq 'Q'){
             $obj->{decode_q} or croak qq(MIME "Q" unsupported);
-            decode_q($1, $3, $chk);
+            $obj->decode_q($1, $3, $chk);
         } else {
             croak qq(MIME "$2" encoding is nonexistent!);
         }
@@ -74,6 +74,7 @@ sub decode($$;$) {
 }
 
 sub decode_b {
+    my $self = shift;
     my $enc  = shift;
     my $d    = find_encoding($enc) or croak qq(Unknown encoding "$enc");
     my $db64 = decode_base64(shift);
@@ -84,7 +85,7 @@ sub decode_b {
 }
 
 sub decode_q {
-    my ( $enc, $q, $chk ) = @_;
+    my ( $self, $enc, $q, $chk ) = @_;
     my $d = find_encoding($enc) or croak qq(Unknown encoding "$enc");
     $q =~ s/_/ /go;
     $q =~ s/=([0-9A-Fa-f]{2})/pack("C", hex($1))/ego;
diff --git a/lib/Encode/MIME/Header/ISO_2022_JP.pm b/lib/Encode/MIME/Header/ISO_2022_JP.pm
index 4abfbd0..e9baf94 100644
--- a/lib/Encode/MIME/Header/ISO_2022_JP.pm
+++ b/lib/Encode/MIME/Header/ISO_2022_JP.pm
@@ -2,11 +2,12 @@ package Encode::MIME::Header::ISO_2022_JP;
 
 use strict;
 use warnings;
+use Carp;
 
 use base qw(Encode::MIME::Header);
 
 $Encode::Encoding{'MIME-Header-ISO_2022_JP'} =
-  bless { encode => 'B', bpl => 76, Name => 'MIME-Header-ISO_2022_JP' } =>
+  bless { decode_b => 1, decode_q => 1, encode => 'B', bpl => 76, Name => 'MIME-Header-ISO_2022_JP' } =>
   __PACKAGE__;
 
 use constant HEAD => '=?ISO-2022-JP?B?';
@@ -35,6 +36,27 @@ sub encode {
     return $str;
 }
 
+sub decode_b {
+    my $self = shift;
+    my ($enc) = @_;
+    if (Encode::resolve_alias($enc) eq 'iso-2022-jp') {
+        $self->SUPER::decode_b(@_);
+    } else {
+        croak qq("$enc" is not support);
+    }
+}
+
+sub decode_q {
+    my $self = shift;
+    my ($enc) = @_;
+    if (Encode::resolve_alias($enc) eq 'iso-2022-jp') {
+        $self->SUPER::decode_q(@_);
+    } else {
+        croak qq("$enc" is not support);
+    }
+}
+
+
 sub _mime_unstructured_header {
     my ( $oldheader, $bpl ) = @_;
     my $crlf = $oldheader =~ /\n$/;
diff --git a/t/mime_header_iso2022jp.t b/t/mime_header_iso2022jp.t
index 818443a..09eaa85 100644
--- a/t/mime_header_iso2022jp.t
+++ b/t/mime_header_iso2022jp.t
@@ -5,7 +5,7 @@ BEGIN {
     if( ord("A") == 193 ) {
 	plan skip_all => 'No Encode::MIME::Header::ISO_2022_JP on EBCDIC Platforms';
     } else {
-	plan tests => 14;
+	plan tests => 14 + 2;
     }
 }
 
@@ -45,4 +45,12 @@ for my $decoded (sort keys %mime){
     is($header, $encoded);
 }
 
+{
+    my $dan = decode('euc-jp', 'だん');
+    is(decode('MIME-Header-ISO_2022_JP', '=?ISO-2022-JP?B?GyRCJEAkcxsoQg==?='), $dan);
+
+    eval { decode('MIME-Header-ISO_2022_JP', '=?UTF-8?B?w6PCgcKgw6PCgsKT?=') };
+    like($@, qr/^"UTF-8" is not support/);
+}
+
 __END__