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.mms.exif;
18
19import com.android.mms.LogTag;
20
21import android.util.Log;
22
23import java.io.IOException;
24import java.io.InputStream;
25
26/**
27 * This class reads the EXIF header of a JPEG file and stores it in
28 * {@link ExifData}.
29 */
30class ExifReader {
31    private static final String TAG = LogTag.TAG;
32
33    private final ExifInterface mInterface;
34
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     */
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