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.mms.exif;
18 
19 import com.android.mms.LogTag;
20 
21 import android.util.Log;
22 
23 import java.io.IOException;
24 import java.io.InputStream;
25 
26 /**
27  * This class reads the EXIF header of a JPEG file and stores it in
28  * {@link ExifData}.
29  */
30 class ExifReader {
31     private static final String TAG = LogTag.TAG;
32 
33     private final ExifInterface mInterface;
34 
ExifReader(ExifInterface iRef)35     ExifReader(ExifInterface iRef) {
36         mInterface = iRef;
37     }
38 
39     /**
40      * Parses the inputStream and and returns the EXIF data in an
41      * {@link ExifData}.
42      *
43      * @throws ExifInvalidFormatException
44      * @throws IOException
45      */
read(InputStream inputStream)46     protected ExifData read(InputStream inputStream) throws ExifInvalidFormatException,
47             IOException {
48         ExifParser parser = ExifParser.parse(inputStream, mInterface);
49         ExifData exifData = new ExifData(parser.getByteOrder());
50         ExifTag tag = null;
51 
52         int event = parser.next();
53         while (event != ExifParser.EVENT_END) {
54             switch (event) {
55                 case ExifParser.EVENT_START_OF_IFD:
56                     exifData.addIfdData(new IfdData(parser.getCurrentIfd()));
57                     break;
58                 case ExifParser.EVENT_NEW_TAG:
59                     tag = parser.getTag();
60                     if (!tag.hasValue()) {
61                         parser.registerForTagValue(tag);
62                     } else {
63                         exifData.getIfdData(tag.getIfd()).setTag(tag);
64                     }
65                     break;
66                 case ExifParser.EVENT_VALUE_OF_REGISTERED_TAG:
67                     tag = parser.getTag();
68                     if (tag.getDataType() == ExifTag.TYPE_UNDEFINED) {
69                         parser.readFullTagValue(tag);
70                     }
71                     exifData.getIfdData(tag.getIfd()).setTag(tag);
72                     break;
73                 case ExifParser.EVENT_COMPRESSED_IMAGE:
74                     byte buf[] = new byte[parser.getCompressedImageSize()];
75                     if (buf.length == parser.read(buf)) {
76                         exifData.setCompressedThumbnail(buf);
77                     } else {
78                         Log.w(TAG, "Failed to read the compressed thumbnail");
79                     }
80                     break;
81                 case ExifParser.EVENT_UNCOMPRESSED_STRIP:
82                     buf = new byte[parser.getStripSize()];
83                     if (buf.length == parser.read(buf)) {
84                         exifData.setStripBytes(parser.getStripIndex(), buf);
85                     } else {
86                         Log.w(TAG, "Failed to read the strip bytes");
87                     }
88                     break;
89             }
90             event = parser.next();
91         }
92         return exifData;
93     }
94 }
95