Bug 343102: cleanup patch for the original fix, r=mscott, sr=neil

mailnews/mime/src/mimeenc.cpp

@@ -100,6 +100,11 @@ mime_decode_qp_buffer (MimeDecoderData *data, const char *buffer, PRInt32 length
 	 trailing whitespace which remains must have been introduced
 	 by a stupid gateway. */
 
+  /* Treat null bytes as spaces when format_out is
+   nsMimeOutput::nsMimeMessageBodyDisplay (see bug 243199 comment 7) */
+  PRBool treatNullAsSpace = data->objectToDecode &&
+                            data->objectToDecode->options->format_out == nsMimeOutput::nsMimeMessageBodyDisplay;
+
   while (length > 0 || i != 0)
 	{
 	  while (i < 3 && length > 0)
@@ -177,20 +182,8 @@ mime_decode_qp_buffer (MimeDecoderData *data, const char *buffer, PRInt32 length
 			  if (in > out) *out++ = token[2];
 			  continue;
 			}
-		  /* treat null bytes as spaces per bug 243199 comment 7 */
-                  /* treat null bytes as null if data->objectToDecode is null
-		   * Reason: Null bytes shall only be displayed as " " when format_out equals nsMimeOutput::nsMimeMessageBodyDisplay
-		   * Bug 344102
-		   */
-		  *out++ =       c
-                               ||( 
-                                    ( 
-                                       data->objectToDecode && 
-                                       data->objectToDecode->options->format_out != nsMimeOutput::nsMimeMessageBodyDisplay
-                                     
-                                    ) || (! (data->objectToDecode ))
-                                 ) ? (char) c : ' ';
 
+			*out++ = c ? (char) c : ((treatNullAsSpace) ? ' ' : (char) c);
 		}
 	  else
 		{