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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 java.util.HashMap;
     20 import java.util.Map;
     21 
     22 /**
     23  * This class stores all the tags in an IFD.
     24  *
     25  * @see ExifData
     26  * @see ExifTag
     27  */
     28 class IfdData {
     29 
     30     private final int mIfdId;
     31     private final Map<Short, ExifTag> mExifTags = new HashMap<Short, ExifTag>();
     32     private int mOffsetToNextIfd = 0;
     33     private static final int[] sIfds = {
     34             IfdId.TYPE_IFD_0, IfdId.TYPE_IFD_1, IfdId.TYPE_IFD_EXIF,
     35             IfdId.TYPE_IFD_INTEROPERABILITY, IfdId.TYPE_IFD_GPS
     36     };
     37     /**
     38      * Creates an IfdData with given IFD ID.
     39      *
     40      * @see IfdId#TYPE_IFD_0
     41      * @see IfdId#TYPE_IFD_1
     42      * @see IfdId#TYPE_IFD_EXIF
     43      * @see IfdId#TYPE_IFD_GPS
     44      * @see IfdId#TYPE_IFD_INTEROPERABILITY
     45      */
     46     IfdData(int ifdId) {
     47         mIfdId = ifdId;
     48     }
     49 
     50     protected static int[] getIfds() {
     51         return sIfds;
     52     }
     53 
     54     /**
     55      * Get a array the contains all {@link ExifTag} in this IFD.
     56      */
     57     protected ExifTag[] getAllTags() {
     58         return mExifTags.values().toArray(new ExifTag[mExifTags.size()]);
     59     }
     60 
     61     /**
     62      * Gets the ID of this IFD.
     63      *
     64      * @see IfdId#TYPE_IFD_0
     65      * @see IfdId#TYPE_IFD_1
     66      * @see IfdId#TYPE_IFD_EXIF
     67      * @see IfdId#TYPE_IFD_GPS
     68      * @see IfdId#TYPE_IFD_INTEROPERABILITY
     69      */
     70     protected int getId() {
     71         return mIfdId;
     72     }
     73 
     74     /**
     75      * Gets the {@link ExifTag} with given tag id. Return null if there is no
     76      * such tag.
     77      */
     78     protected ExifTag getTag(short tagId) {
     79         return mExifTags.get(tagId);
     80     }
     81 
     82     /**
     83      * Adds or replaces a {@link ExifTag}.
     84      */
     85     protected ExifTag setTag(ExifTag tag) {
     86         tag.setIfd(mIfdId);
     87         return mExifTags.put(tag.getTagId(), tag);
     88     }
     89 
     90     protected boolean checkCollision(short tagId) {
     91         return mExifTags.get(tagId) != null;
     92     }
     93 
     94     /**
     95      * Removes the tag of the given ID
     96      */
     97     protected void removeTag(short tagId) {
     98         mExifTags.remove(tagId);
     99     }
    100 
    101     /**
    102      * Gets the tags count in the IFD.
    103      */
    104     protected int getTagCount() {
    105         return mExifTags.size();
    106     }
    107 
    108     /**
    109      * Sets the offset of next IFD.
    110      */
    111     protected void setOffsetToNextIfd(int offset) {
    112         mOffsetToNextIfd = offset;
    113     }
    114 
    115     /**
    116      * Gets the offset of next IFD.
    117      */
    118     protected int getOffsetToNextIfd() {
    119         return mOffsetToNextIfd;
    120     }
    121 
    122     /**
    123      * Returns true if all tags in this two IFDs are equal. Note that tags of
    124      * IFDs offset or thumbnail offset will be ignored.
    125      */
    126     @Override
    127     public boolean equals(Object obj) {
    128         if (this == obj) {
    129             return true;
    130         }
    131         if (obj == null) {
    132             return false;
    133         }
    134         if (obj instanceof IfdData) {
    135             IfdData data = (IfdData) obj;
    136             if (data.getId() == mIfdId && data.getTagCount() == getTagCount()) {
    137                 ExifTag[] tags = data.getAllTags();
    138                 for (ExifTag tag : tags) {
    139                     if (ExifInterface.isOffsetTag(tag.getTagId())) {
    140                         continue;
    141                     }
    142                     ExifTag tag2 = mExifTags.get(tag.getTagId());
    143                     if (!tag.equals(tag2)) {
    144                         return false;
    145                     }
    146                 }
    147                 return true;
    148             }
    149         }
    150         return false;
    151     }
    152 }
    153