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      1 /*
      2  * Copyright (C) 2012 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.messaging.util.exif;
     18 
     19 import android.util.Log;
     20 import com.android.messaging.util.LogUtil;
     21 
     22 import java.io.IOException;
     23 import java.io.InputStream;
     24 
     25 /**
     26  * This class reads the EXIF header of a JPEG file and stores it in
     27  * {@link ExifData}.
     28  */
     29 class ExifReader {
     30     private static final String TAG = LogUtil.BUGLE_TAG;
     31 
     32     private final ExifInterface mInterface;
     33 
     34     ExifReader(ExifInterface iRef) {
     35         mInterface = iRef;
     36     }
     37 
     38     /**
     39      * Parses the inputStream and and returns the EXIF data in an
     40      * {@link ExifData}.
     41      *
     42      * @throws ExifInvalidFormatException
     43      * @throws java.io.IOException
     44      */
     45     protected ExifData read(InputStream inputStream) throws ExifInvalidFormatException,
     46             IOException {
     47         ExifParser parser = ExifParser.parse(inputStream, mInterface);
     48         ExifData exifData = new ExifData(parser.getByteOrder());
     49         ExifTag tag = null;
     50 
     51         int event = parser.next();
     52         while (event != ExifParser.EVENT_END) {
     53             switch (event) {
     54                 case ExifParser.EVENT_START_OF_IFD:
     55                     exifData.addIfdData(new IfdData(parser.getCurrentIfd()));
     56                     break;
     57                 case ExifParser.EVENT_NEW_TAG:
     58                     tag = parser.getTag();
     59                     if (!tag.hasValue()) {
     60                         parser.registerForTagValue(tag);
     61                     } else {
     62                         exifData.getIfdData(tag.getIfd()).setTag(tag);
     63                     }
     64                     break;
     65                 case ExifParser.EVENT_VALUE_OF_REGISTERED_TAG:
     66                     tag = parser.getTag();
     67                     if (tag.getDataType() == ExifTag.TYPE_UNDEFINED) {
     68                         parser.readFullTagValue(tag);
     69                     }
     70                     exifData.getIfdData(tag.getIfd()).setTag(tag);
     71                     break;
     72                 case ExifParser.EVENT_COMPRESSED_IMAGE:
     73                     byte buf[] = new byte[parser.getCompressedImageSize()];
     74                     if (buf.length == parser.read(buf)) {
     75                         exifData.setCompressedThumbnail(buf);
     76                     } else {
     77                         Log.w(TAG, "Failed to read the compressed thumbnail");
     78                     }
     79                     break;
     80                 case ExifParser.EVENT_UNCOMPRESSED_STRIP:
     81                     buf = new byte[parser.getStripSize()];
     82                     if (buf.length == parser.read(buf)) {
     83                         exifData.setStripBytes(parser.getStripIndex(), buf);
     84                     } else {
     85                         Log.w(TAG, "Failed to read the strip bytes");
     86                     }
     87                     break;
     88             }
     89             event = parser.next();
     90         }
     91         return exifData;
     92     }
     93 }
     94