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.UnsupportedEncodingException;
24import java.nio.ByteOrder;
25import java.util.ArrayList;
26import java.util.Arrays;
27import java.util.List;
28
29/**
30 * This class stores the EXIF header in IFDs according to the JPEG
31 * specification. It is the result produced by {@link ExifReader}.
32 *
33 * @see ExifReader
34 * @see IfdData
35 */
36class ExifData {
37    private static final String TAG = LogTag.TAG;
38    private static final byte[] USER_COMMENT_ASCII = {
39            0x41, 0x53, 0x43, 0x49, 0x49, 0x00, 0x00, 0x00
40    };
41    private static final byte[] USER_COMMENT_JIS = {
42            0x4A, 0x49, 0x53, 0x00, 0x00, 0x00, 0x00, 0x00
43    };
44    private static final byte[] USER_COMMENT_UNICODE = {
45            0x55, 0x4E, 0x49, 0x43, 0x4F, 0x44, 0x45, 0x00
46    };
47
48    private final IfdData[] mIfdDatas = new IfdData[IfdId.TYPE_IFD_COUNT];
49    private byte[] mThumbnail;
50    private final ArrayList<byte[]> mStripBytes = new ArrayList<byte[]>();
51    private final ByteOrder mByteOrder;
52
53    ExifData(ByteOrder order) {
54        mByteOrder = order;
55    }
56
57    /**
58     * Gets the compressed thumbnail. Returns null if there is no compressed
59     * thumbnail.
60     *
61     * @see #hasCompressedThumbnail()
62     */
63    protected byte[] getCompressedThumbnail() {
64        return mThumbnail;
65    }
66
67    /**
68     * Sets the compressed thumbnail.
69     */
70    protected void setCompressedThumbnail(byte[] thumbnail) {
71        mThumbnail = thumbnail;
72    }
73
74    /**
75     * Returns true it this header contains a compressed thumbnail.
76     */
77    protected boolean hasCompressedThumbnail() {
78        return mThumbnail != null;
79    }
80
81    /**
82     * Adds an uncompressed strip.
83     */
84    protected void setStripBytes(int index, byte[] strip) {
85        if (index < mStripBytes.size()) {
86            mStripBytes.set(index, strip);
87        } else {
88            for (int i = mStripBytes.size(); i < index; i++) {
89                mStripBytes.add(null);
90            }
91            mStripBytes.add(strip);
92        }
93    }
94
95    /**
96     * Gets the strip count.
97     */
98    protected int getStripCount() {
99        return mStripBytes.size();
100    }
101
102    /**
103     * Gets the strip at the specified index.
104     *
105     * @exceptions #IndexOutOfBoundException
106     */
107    protected byte[] getStrip(int index) {
108        return mStripBytes.get(index);
109    }
110
111    /**
112     * Returns true if this header contains uncompressed strip.
113     */
114    protected boolean hasUncompressedStrip() {
115        return mStripBytes.size() != 0;
116    }
117
118    /**
119     * Gets the byte order.
120     */
121    protected ByteOrder getByteOrder() {
122        return mByteOrder;
123    }
124
125    /**
126     * Returns the {@link IfdData} object corresponding to a given IFD if it
127     * exists or null.
128     */
129    protected IfdData getIfdData(int ifdId) {
130        if (ExifTag.isValidIfd(ifdId)) {
131            return mIfdDatas[ifdId];
132        }
133        return null;
134    }
135
136    /**
137     * Adds IFD data. If IFD data of the same type already exists, it will be
138     * replaced by the new data.
139     */
140    protected void addIfdData(IfdData data) {
141        mIfdDatas[data.getId()] = data;
142    }
143
144    /**
145     * Returns the {@link IfdData} object corresponding to a given IFD or
146     * generates one if none exist.
147     */
148    protected IfdData getOrCreateIfdData(int ifdId) {
149        IfdData ifdData = mIfdDatas[ifdId];
150        if (ifdData == null) {
151            ifdData = new IfdData(ifdId);
152            mIfdDatas[ifdId] = ifdData;
153        }
154        return ifdData;
155    }
156
157    /**
158     * Returns the tag with a given TID in the given IFD if the tag exists.
159     * Otherwise returns null.
160     */
161    protected ExifTag getTag(short tag, int ifd) {
162        IfdData ifdData = mIfdDatas[ifd];
163        return (ifdData == null) ? null : ifdData.getTag(tag);
164    }
165
166    /**
167     * Adds the given ExifTag to its default IFD and returns an existing ExifTag
168     * with the same TID or null if none exist.
169     */
170    protected ExifTag addTag(ExifTag tag) {
171        if (tag != null) {
172            int ifd = tag.getIfd();
173            return addTag(tag, ifd);
174        }
175        return null;
176    }
177
178    /**
179     * Adds the given ExifTag to the given IFD and returns an existing ExifTag
180     * with the same TID or null if none exist.
181     */
182    protected ExifTag addTag(ExifTag tag, int ifdId) {
183        if (tag != null && ExifTag.isValidIfd(ifdId)) {
184            IfdData ifdData = getOrCreateIfdData(ifdId);
185            return ifdData.setTag(tag);
186        }
187        return null;
188    }
189
190    protected void clearThumbnailAndStrips() {
191        mThumbnail = null;
192        mStripBytes.clear();
193    }
194
195    /**
196     * Removes the thumbnail and its related tags. IFD1 will be removed.
197     */
198    protected void removeThumbnailData() {
199        clearThumbnailAndStrips();
200        mIfdDatas[IfdId.TYPE_IFD_1] = null;
201    }
202
203    /**
204     * Removes the tag with a given TID and IFD.
205     */
206    protected void removeTag(short tagId, int ifdId) {
207        IfdData ifdData = mIfdDatas[ifdId];
208        if (ifdData == null) {
209            return;
210        }
211        ifdData.removeTag(tagId);
212    }
213
214    /**
215     * Decodes the user comment tag into string as specified in the EXIF
216     * standard. Returns null if decoding failed.
217     */
218    protected String getUserComment() {
219        IfdData ifdData = mIfdDatas[IfdId.TYPE_IFD_0];
220        if (ifdData == null) {
221            return null;
222        }
223        ExifTag tag = ifdData.getTag(ExifInterface.getTrueTagKey(ExifInterface.TAG_USER_COMMENT));
224        if (tag == null) {
225            return null;
226        }
227        if (tag.getComponentCount() < 8) {
228            return null;
229        }
230
231        byte[] buf = new byte[tag.getComponentCount()];
232        tag.getBytes(buf);
233
234        byte[] code = new byte[8];
235        System.arraycopy(buf, 0, code, 0, 8);
236
237        try {
238            if (Arrays.equals(code, USER_COMMENT_ASCII)) {
239                return new String(buf, 8, buf.length - 8, "US-ASCII");
240            } else if (Arrays.equals(code, USER_COMMENT_JIS)) {
241                return new String(buf, 8, buf.length - 8, "EUC-JP");
242            } else if (Arrays.equals(code, USER_COMMENT_UNICODE)) {
243                return new String(buf, 8, buf.length - 8, "UTF-16");
244            } else {
245                return null;
246            }
247        } catch (UnsupportedEncodingException e) {
248            Log.w(TAG, "Failed to decode the user comment");
249            return null;
250        }
251    }
252
253    /**
254     * Returns a list of all {@link ExifTag}s in the ExifData or null if there
255     * are none.
256     */
257    protected List<ExifTag> getAllTags() {
258        ArrayList<ExifTag> ret = new ArrayList<ExifTag>();
259        for (IfdData d : mIfdDatas) {
260            if (d != null) {
261                ExifTag[] tags = d.getAllTags();
262                if (tags != null) {
263                    for (ExifTag t : tags) {
264                        ret.add(t);
265                    }
266                }
267            }
268        }
269        if (ret.size() == 0) {
270            return null;
271        }
272        return ret;
273    }
274
275    /**
276     * Returns a list of all {@link ExifTag}s in a given IFD or null if there
277     * are none.
278     */
279    protected List<ExifTag> getAllTagsForIfd(int ifd) {
280        IfdData d = mIfdDatas[ifd];
281        if (d == null) {
282            return null;
283        }
284        ExifTag[] tags = d.getAllTags();
285        if (tags == null) {
286            return null;
287        }
288        ArrayList<ExifTag> ret = new ArrayList<ExifTag>(tags.length);
289        for (ExifTag t : tags) {
290            ret.add(t);
291        }
292        if (ret.size() == 0) {
293            return null;
294        }
295        return ret;
296    }
297
298    /**
299     * Returns a list of all {@link ExifTag}s with a given TID or null if there
300     * are none.
301     */
302    protected List<ExifTag> getAllTagsForTagId(short tag) {
303        ArrayList<ExifTag> ret = new ArrayList<ExifTag>();
304        for (IfdData d : mIfdDatas) {
305            if (d != null) {
306                ExifTag t = d.getTag(tag);
307                if (t != null) {
308                    ret.add(t);
309                }
310            }
311        }
312        if (ret.size() == 0) {
313            return null;
314        }
315        return ret;
316    }
317
318    @Override
319    public boolean equals(Object obj) {
320        if (this == obj) {
321            return true;
322        }
323        if (obj == null) {
324            return false;
325        }
326        if (obj instanceof ExifData) {
327            ExifData data = (ExifData) obj;
328            if (data.mByteOrder != mByteOrder ||
329                    data.mStripBytes.size() != mStripBytes.size() ||
330                    !Arrays.equals(data.mThumbnail, mThumbnail)) {
331                return false;
332            }
333            for (int i = 0; i < mStripBytes.size(); i++) {
334                if (!Arrays.equals(data.mStripBytes.get(i), mStripBytes.get(i))) {
335                    return false;
336                }
337            }
338            for (int i = 0; i < IfdId.TYPE_IFD_COUNT; i++) {
339                IfdData ifd1 = data.getIfdData(i);
340                IfdData ifd2 = getIfdData(i);
341                if (ifd1 != ifd2 && ifd1 != null && !ifd1.equals(ifd2)) {
342                    return false;
343                }
344            }
345            return true;
346        }
347        return false;
348    }
349
350}
351