Android Open Source - Android-Exif Exif Reader

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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
 */* w w w .j  a  va 2 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.IOException;
import java.io.InputStream;

import android.util.Log;

/**
 * This class reads the EXIF header of a JPEG file and stores it in
 * {@link ExifData}.
 * 
 * <p>
 * Copy from and com.android.camera.exif
 * 
 * @author leo
 */
class ExifReader {
  private static final String TAG = "ExifReader";

  private final ExifInterface mInterface;

  ExifReader(ExifInterface iRef) {
    mInterface = iRef;
  }

  /**
   * Parses the inputStream and and returns the EXIF data in an
   * {@link ExifData}.
   * 
   * @throws ExifInvalidFormatException
   * @throws IOException
   */
  protected ExifData read(InputStream inputStream) throws ExifInvalidFormatException, IOException {
    ExifParser parser = ExifParser.parse(inputStream, mInterface);
    ExifData exifData = new ExifData(parser.getByteOrder());
    ExifTag tag = null;

    int event = parser.next();
    while (event != ExifParser.EVENT_END) {
      switch (event) {
      case ExifParser.EVENT_START_OF_IFD:
        exifData.addIfdData(new IfdData(parser.getCurrentIfd()));
        break;
      case ExifParser.EVENT_NEW_TAG:
        tag = parser.getTag();
        if (!tag.hasValue()) {
          parser.registerForTagValue(tag);
        } else {
          exifData.getIfdData(tag.getIfd()).setTag(tag);
        }
        break;
      case ExifParser.EVENT_VALUE_OF_REGISTERED_TAG:
        tag = parser.getTag();
        if (tag.getDataType() == ExifTag.TYPE_UNDEFINED) {
          parser.readFullTagValue(tag);
        }
        exifData.getIfdData(tag.getIfd()).setTag(tag);
        break;
      case ExifParser.EVENT_COMPRESSED_IMAGE:
        byte buf[] = new byte[parser.getCompressedImageSize()];
        if (buf.length == parser.read(buf)) {
          exifData.setCompressedThumbnail(buf);
        } else {
          Log.w(TAG, "Failed to read the compressed thumbnail");
        }
        break;
      case ExifParser.EVENT_UNCOMPRESSED_STRIP:
        buf = new byte[parser.getStripSize()];
        if (buf.length == parser.read(buf)) {
          exifData.setStripBytes(parser.getStripIndex(), buf);
        } else {
          Log.w(TAG, "Failed to read the strip bytes");
        }
        break;
      }
      event = parser.next();
    }
    return exifData;
  }
}

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