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      1 /*
      2  * Copyright (C) 2013 The Android Open Source Project
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *      http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 
     17 package com.android.accessorydisplay.common;
     18 
     19 /**
     20  * Defines message types.
     21  */
     22 public class Protocol {
     23     // Message header.
     24     //   0: service id (16 bits)
     25     //   2: what (16 bits)
     26     //   4: content size (32 bits)
     27     //   8: ... content follows ...
     28     static final int HEADER_SIZE = 8;
     29 
     30     // Maximum size of a message envelope including the header and contents.
     31     static final int MAX_ENVELOPE_SIZE = 64 * 1024;
     32 
     33     /**
     34      * Maximum message content size.
     35      */
     36     public static final int MAX_CONTENT_SIZE = MAX_ENVELOPE_SIZE - HEADER_SIZE;
     37 
     38     public static final class DisplaySinkService {
     39         private DisplaySinkService() { }
     40 
     41         public static final int ID = 1;
     42 
     43         // Query sink capabilities.
     44         // Replies with sink available or not available.
     45         public static final int MSG_QUERY = 1;
     46 
     47         // Send MPEG2-TS H.264 encoded content.
     48         public static final int MSG_CONTENT = 2;
     49     }
     50 
     51     public static final class DisplaySourceService {
     52         private DisplaySourceService() { }
     53 
     54         public static final int ID = 2;
     55 
     56         // Sink is now available for use.
     57         //   0: width (32 bits)
     58         //   4: height (32 bits)
     59         //   8: density dpi (32 bits)
     60         public static final int MSG_SINK_AVAILABLE = 1;
     61 
     62         // Sink is no longer available for use.
     63         public static final int MSG_SINK_NOT_AVAILABLE = 2;
     64     }
     65 }
     66