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
17package com.android.messaging.util.exif;
18
19import android.util.Log;
20import com.android.messaging.util.LogUtil;
21
22import java.io.IOException;
23import java.io.InputStream;
24
25/**
26 * This class reads the EXIF header of a JPEG file and stores it in
27 * {@link ExifData}.
28 */
29class 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