Android Open Source - Android-Exif Exif Data

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License

The source code is released under:

GNU General Public License

Java Source Code

/*
 * Copyright (C) 2012 The Android Open Source Project
 *//from   w ww.  j av  a2  s.  c  o m
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.ai.exif;

import java.io.UnsupportedEncodingException;
import java.nio.ByteOrder;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;

import android.util.Log;

/**
 * This class stores the EXIF header in IFDs according to the JPEG
 * specification. It is the result produced by {@link ExifReader}.
 * <p>
 * Copy from and com.android.camera.exif
 * 
 * @author leo
 * @see ExifReader
 * @see IfdData
 */
class ExifData {
  private static final String TAG = "ExifData";
  private static final byte[] USER_COMMENT_ASCII = { 0x41, 0x53, 0x43, 0x49, 0x49, 0x00, 0x00, 0x00 };
  private static final byte[] USER_COMMENT_JIS = { 0x4A, 0x49, 0x53, 0x00, 0x00, 0x00, 0x00, 0x00 };
  private static final byte[] USER_COMMENT_UNICODE = { 0x55, 0x4E, 0x49, 0x43, 0x4F, 0x44, 0x45, 0x00 };

  private final IfdData[] mIfdDatas = new IfdData[IfdId.TYPE_IFD_COUNT];
  private byte[] mThumbnail;
  private final ArrayList<byte[]> mStripBytes = new ArrayList<byte[]>();
  private final ByteOrder mByteOrder;

  ExifData(ByteOrder order) {
    mByteOrder = order;
  }

  /**
   * Gets the compressed thumbnail. Returns null if there is no compressed
   * thumbnail.
   * 
   * @see #hasCompressedThumbnail()
   */
  protected byte[] getCompressedThumbnail() {
    return mThumbnail;
  }

  /**
   * Sets the compressed thumbnail.
   */
  protected void setCompressedThumbnail(byte[] thumbnail) {
    mThumbnail = thumbnail;
  }

  /**
   * Returns true it this header contains a compressed thumbnail.
   */
  protected boolean hasCompressedThumbnail() {
    return mThumbnail != null;
  }

  /**
   * Adds an uncompressed strip.
   */
  protected void setStripBytes(int index, byte[] strip) {
    if (index < mStripBytes.size()) {
      mStripBytes.set(index, strip);
    } else {
      for (int i = mStripBytes.size(); i < index; i++) {
        mStripBytes.add(null);
      }
      mStripBytes.add(strip);
    }
  }

  /**
   * Gets the strip count.
   */
  protected int getStripCount() {
    return mStripBytes.size();
  }

  /**
   * Gets the strip at the specified index.
   * 
   * @exceptions #IndexOutOfBoundException
   */
  protected byte[] getStrip(int index) {
    return mStripBytes.get(index);
  }

  /**
   * Returns true if this header contains uncompressed strip.
   */
  protected boolean hasUncompressedStrip() {
    return mStripBytes.size() != 0;
  }

  /**
   * Gets the byte order.
   */
  protected ByteOrder getByteOrder() {
    return mByteOrder;
  }

  /**
   * Returns the {@link IfdData} object corresponding to a given IFD if it
   * exists or null.
   */
  protected IfdData getIfdData(int ifdId) {
    if (ExifTag.isValidIfd(ifdId)) {
      return mIfdDatas[ifdId];
    }
    return null;
  }

  /**
   * Adds IFD data. If IFD data of the same type already exists, it will be
   * replaced by the new data.
   */
  protected void addIfdData(IfdData data) {
    mIfdDatas[data.getId()] = data;
  }

  /**
   * Returns the {@link IfdData} object corresponding to a given IFD or
   * generates one if none exist.
   */
  protected IfdData getOrCreateIfdData(int ifdId) {
    IfdData ifdData = mIfdDatas[ifdId];
    if (ifdData == null) {
      ifdData = new IfdData(ifdId);
      mIfdDatas[ifdId] = ifdData;
    }
    return ifdData;
  }

  /**
   * Returns the tag with a given TID in the given IFD if the tag exists.
   * Otherwise returns null.
   */
  protected ExifTag getTag(short tag, int ifd) {
    IfdData ifdData = mIfdDatas[ifd];
    return (ifdData == null) ? null : ifdData.getTag(tag);
  }

  /**
   * Adds the given ExifTag to its default IFD and returns an existing ExifTag
   * with the same TID or null if none exist.
   */
  protected ExifTag addTag(ExifTag tag) {
    if (tag != null) {
      int ifd = tag.getIfd();
      return addTag(tag, ifd);
    }
    return null;
  }

  /**
   * Adds the given ExifTag to the given IFD and returns an existing ExifTag
   * with the same TID or null if none exist.
   */
  protected ExifTag addTag(ExifTag tag, int ifdId) {
    if (tag != null && ExifTag.isValidIfd(ifdId)) {
      IfdData ifdData = getOrCreateIfdData(ifdId);
      return ifdData.setTag(tag);
    }
    return null;
  }

  protected void clearThumbnailAndStrips() {
    mThumbnail = null;
    mStripBytes.clear();
  }

  /**
   * Removes the thumbnail and its related tags. IFD1 will be removed.
   */
  protected void removeThumbnailData() {
    clearThumbnailAndStrips();
    mIfdDatas[IfdId.TYPE_IFD_1] = null;
  }

  /**
   * Removes the tag with a given TID and IFD.
   */
  protected void removeTag(short tagId, int ifdId) {
    IfdData ifdData = mIfdDatas[ifdId];
    if (ifdData == null) {
      return;
    }
    ifdData.removeTag(tagId);
  }

  /**
   * Decodes the user comment tag into string as specified in the EXIF
   * standard. Returns null if decoding failed.
   */
  protected String getUserComment() {
    IfdData ifdData = mIfdDatas[IfdId.TYPE_IFD_0];
    if (ifdData == null) {
      return null;
    }
    ExifTag tag = ifdData.getTag(ExifInterface.getTrueTagKey(ExifInterface.TAG_USER_COMMENT));
    if (tag == null) {
      return null;
    }
    if (tag.getComponentCount() < 8) {
      return null;
    }

    byte[] buf = new byte[tag.getComponentCount()];
    tag.getBytes(buf);

    byte[] code = new byte[8];
    System.arraycopy(buf, 0, code, 0, 8);

    try {
      if (Arrays.equals(code, USER_COMMENT_ASCII)) {
        return new String(buf, 8, buf.length - 8, "US-ASCII");
      } else if (Arrays.equals(code, USER_COMMENT_JIS)) {
        return new String(buf, 8, buf.length - 8, "EUC-JP");
      } else if (Arrays.equals(code, USER_COMMENT_UNICODE)) {
        return new String(buf, 8, buf.length - 8, "UTF-16");
      } else {
        return null;
      }
    } catch (UnsupportedEncodingException e) {
      Log.w(TAG, "Failed to decode the user comment");
      return null;
    }
  }

  /**
   * Returns a list of all {@link ExifTag}s in the ExifData or null if there
   * are none.
   */
  protected List<ExifTag> getAllTags() {
    ArrayList<ExifTag> ret = new ArrayList<ExifTag>();
    for (IfdData d : mIfdDatas) {
      if (d != null) {
        ExifTag[] tags = d.getAllTags();
        if (tags != null) {
          for (ExifTag t : tags) {
            ret.add(t);
          }
        }
      }
    }
    if (ret.size() == 0) {
      return null;
    }
    return ret;
  }

  /**
   * Returns a list of all {@link ExifTag}s in a given IFD or null if there
   * are none.
   */
  protected List<ExifTag> getAllTagsForIfd(int ifd) {
    IfdData d = mIfdDatas[ifd];
    if (d == null) {
      return null;
    }
    ExifTag[] tags = d.getAllTags();
    if (tags == null) {
      return null;
    }
    ArrayList<ExifTag> ret = new ArrayList<ExifTag>(tags.length);
    for (ExifTag t : tags) {
      ret.add(t);
    }
    if (ret.size() == 0) {
      return null;
    }
    return ret;
  }

  /**
   * Returns a list of all {@link ExifTag}s with a given TID or null if there
   * are none.
   */
  protected List<ExifTag> getAllTagsForTagId(short tag) {
    ArrayList<ExifTag> ret = new ArrayList<ExifTag>();
    for (IfdData d : mIfdDatas) {
      if (d != null) {
        ExifTag t = d.getTag(tag);
        if (t != null) {
          ret.add(t);
        }
      }
    }
    if (ret.size() == 0) {
      return null;
    }
    return ret;
  }

  @Override
  public boolean equals(Object obj) {
    if (this == obj) {
      return true;
    }
    if (obj == null) {
      return false;
    }
    if (obj instanceof ExifData) {
      ExifData data = (ExifData) obj;
      if (data.mByteOrder != mByteOrder || data.mStripBytes.size() != mStripBytes.size() || !Arrays.equals(data.mThumbnail, mThumbnail)) {
        return false;
      }
      for (int i = 0; i < mStripBytes.size(); i++) {
        if (!Arrays.equals(data.mStripBytes.get(i), mStripBytes.get(i))) {
          return false;
        }
      }
      for (int i = 0; i < IfdId.TYPE_IFD_COUNT; i++) {
        IfdData ifd1 = data.getIfdData(i);
        IfdData ifd2 = getIfdData(i);
        if (ifd1 != ifd2 && ifd1 != null && !ifd1.equals(ifd2)) {
          return false;
        }
      }
      return true;
    }
    return false;
  }

}

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