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      1 /*
      2  * Copyright 2011 castLabs, Berlin
      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.googlecode.mp4parser.boxes.mp4.objectdescriptors;
     18 
     19 import com.coremedia.iso.IsoTypeReader;
     20 
     21 import java.io.IOException;
     22 import java.nio.ByteBuffer;
     23 
     24 /*
     25 abstract aligned(8) expandable(228-1) class BaseDescriptor : bit(8) tag=0 {
     26 // empty. To be filled by classes extending this class.
     27 }
     28 
     29 int sizeOfInstance = 0;
     30 bit(1) nextByte;
     31 bit(7) sizeOfInstance;
     32 while(nextByte) {
     33 bit(1) nextByte;
     34 bit(7) sizeByte;
     35 sizeOfInstance = sizeOfInstance<<7 | sizeByte;
     36 }
     37  */
     38 @Descriptor(tags = 0x00)
     39 public abstract class BaseDescriptor {
     40     int tag;
     41     int sizeOfInstance;
     42     int sizeBytes;
     43 
     44     public BaseDescriptor() {
     45     }
     46 
     47     public int getTag() {
     48         return tag;
     49     }
     50 
     51     public int getSize() {
     52         return sizeOfInstance
     53                 + 1//1 for the tag
     54                 + sizeBytes;
     55     }
     56 
     57     public int getSizeOfInstance() {
     58         return sizeOfInstance;
     59     }
     60 
     61     public int getSizeBytes() {
     62         return sizeBytes;
     63     }
     64 
     65     public final void parse(int tag, ByteBuffer bb) throws IOException {
     66         this.tag = tag;
     67 
     68         int i = 0;
     69         int tmp = IsoTypeReader.readUInt8(bb);
     70         i++;
     71         sizeOfInstance = tmp & 0x7f;
     72         while (tmp >>> 7 == 1) { //nextbyte indicator bit
     73             tmp = IsoTypeReader.readUInt8(bb);
     74             i++;
     75             //sizeOfInstance = sizeOfInstance<<7 | sizeByte;
     76             sizeOfInstance = sizeOfInstance << 7 | tmp & 0x7f;
     77         }
     78         sizeBytes = i;
     79         ByteBuffer detailSource = bb.slice();
     80         detailSource.limit(sizeOfInstance);
     81         parseDetail(detailSource);
     82         assert detailSource.remaining() == 0: this.getClass().getSimpleName() + " has not been fully parsed";
     83         bb.position(bb.position() + sizeOfInstance);
     84     }
     85 
     86     public abstract void parseDetail(ByteBuffer bb) throws IOException;
     87 
     88 
     89 
     90     @Override
     91     public String toString() {
     92         final StringBuilder sb = new StringBuilder();
     93         sb.append("BaseDescriptor");
     94         sb.append("{tag=").append(tag);
     95         sb.append(", sizeOfInstance=").append(sizeOfInstance);
     96         sb.append('}');
     97         return sb.toString();
     98     }
     99 }
    100