Fix improper padding in B encoding

* libmailutils/stream/fltstream.c: stop encoding when no more
input is available.
* libmailutils/tests/encode2047.at: add new tests.
* libmailutils/filter/base64.c (_base64_encoder): detect eof

@@ -233,6 +233,13 @@ _base64_encoder (void *xd,
       break;
     }
 
+  if (iobuf->isize == 0)
+    {
+      iobuf->osize = 0;
+      iobuf->eof = 1;
+      return mu_filter_ok;
+    }
+  
   if (iobuf->isize <= 3)
     {
       if (cmd == mu_filter_lastbuf)

@@ -149,7 +149,7 @@ filter_read (mu_stream_t stream, char *buf, size_t size, size_t *pret)
 	      if (rdsize == 0 &&
 		  MFB_RDBYTES (fs->outbuf) == 0 &&
 		  MFB_RDBYTES (fs->inbuf) == 0)
-		cmd = mu_filter_lastbuf;
+		break;
 	      
 	      MFB_advance_level (&fs->inbuf, rdsize);
 	    }

@@ -14,18 +14,41 @@
 # You should have received a copy of the GNU General Public License
 # along with GNU Mailutils.  If not, see <http://www.gnu.org/licenses/>.
 
-AT_SETUP([encode2047])
-AT_KEYWORDS([encode])
-
-AT_CHECK([
-AT_DATA(input,[dnl
-\\345\326\305\304\316\305\327\316\331\312\040\317\324\336\305\324
+dnl ------------------------------------------------------------
+dnl TESTENC2047([NAME], [KW = `'], [OPT], [INPUT], [STDOUT = `'])
+dnl
+m4_pushdef([TESTENC2047],[
+m4_pushdef([MU_TEST_GROUP],[Encode 2047])
+m4_pushdef([MU_TEST_KEYWORDS],[encode2047 encode])
+m4_pushdef([MU_TEST_COMMAND],[encode2047 -eB $3])
+MU_GENERIC_TEST([$1],[$2],[$4],[],[$5
 ])
-
-encode2047 -c koi8-r -eB -o < input],
-[0],
-[=?koi8-r?B?5dbFxM7F187ZyiDP1N7F1A==?=
+m4_popdef([MU_TEST_COMMAND])
+m4_popdef([MU_TEST_KEYWORDS])
+m4_popdef([MU_TEST_GROUP])
 ])
 
-AT_CLEANUP
+TESTENC2047([8-bit input],[enc01],
+            [-c koi8-r -o],
+            [\\345\326\305\304\316\305\327\316\331\312\040\317\324\336\305\324],
+            [=?koi8-r?B?5dbFxM7F187ZyiDP1N7F1A==?=])
+
+TESTENC2047([padding 1],[enc02],
+            [],
+            [abcd],
+	    [=?iso-8859-1?B?YWJjZA==?=])
+	    
+TESTENC2047([padding 2],[enc03],
+            [],
+            [abcdef],
+	    [=?iso-8859-1?B?YWJjZGVm?=])
+
+TESTENC2047([padding 3],[enc04],
+            [-cUTF-8],
+	    [Wichtige Mitteilung zur Schaltung Ihres Anschlusses],
+	    [=?UTF-8?B?V2ljaHRpZ2UgTWl0dGVpbHVuZyB6dXIgU2NoYWx0dW5nIElocmVzIEFuc2NobHVzc2Vz?=])
+	    
+	    
+m4_popdef([TESTENC2047])
+