| /* |
| * Copyright (C) 2012 The Android Open Source Project |
| * |
| * 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.android.gallery3d.exif; |
| |
| import java.io.DataInputStream; |
| import java.io.EOFException; |
| import java.io.IOException; |
| import java.io.InputStream; |
| import java.nio.ByteOrder; |
| import java.nio.charset.Charset; |
| import java.util.Map.Entry; |
| import java.util.TreeMap; |
| |
| /** |
| * This class provides a low-level EXIF parsing API. Given a JPEG format InputStream, the caller |
| * can request which IFD's to read via {@link #parse(InputStream, int)} with given options. |
| * <p> |
| * Below is an example of getting EXIF data from IFD 0 and EXIF IFD using the parser. |
| * <pre> |
| * void parse() { |
| * ExifParser parser = ExifParser.parse(mImageInputStream, |
| * ExifParser.OPTION_IFD_0 | ExifParser.OPTIONS_IFD_EXIF); |
| * int event = parser.next(); |
| * while (event != ExifParser.EVENT_END) { |
| * switch (event) { |
| * case ExifParser.EVENT_START_OF_IFD: |
| * break; |
| * case ExifParser.EVENT_NEW_TAG: |
| * ExifTag tag = parser.getTag(); |
| * if (!tag.hasValue()) { |
| * parser.registerForTagValue(tag); |
| * } else { |
| * processTag(tag); |
| * } |
| * break; |
| * case ExifParser.EVENT_VALUE_OF_REGISTERED_TAG: |
| * tag = parser.getTag(); |
| * if (tag.getDataType() != ExifTag.TYPE_UNDEFINED) { |
| * processTag(tag); |
| * } |
| * break; |
| * } |
| * event = parser.next(); |
| * } |
| * } |
| * |
| * void processTag(ExifTag tag) { |
| * // process the tag as you like. |
| * } |
| * </pre> |
| */ |
| public class ExifParser { |
| /** |
| * When the parser reaches a new IFD area. Call |
| * {@link #getCurrentIfd()} to know which IFD we are in. |
| */ |
| public static final int EVENT_START_OF_IFD = 0; |
| /** |
| * When the parser reaches a new tag. Call {@link #getTag()}to get the |
| * corresponding tag. |
| */ |
| public static final int EVENT_NEW_TAG = 1; |
| /** |
| * When the parser reaches the value area of tag that is registered by |
| * {@link #registerForTagValue(ExifTag)} previously. Call |
| * {@link #getTag()} to get the corresponding tag. |
| */ |
| public static final int EVENT_VALUE_OF_REGISTERED_TAG = 2; |
| |
| /** |
| * When the parser reaches the compressed image area. |
| */ |
| public static final int EVENT_COMPRESSED_IMAGE = 3; |
| /** |
| * When the parser reaches the uncompressed image strip. |
| * Call {@link #getStripIndex()} to get the index of the strip. |
| * @see #getStripIndex() |
| * @see #getStripCount() |
| */ |
| public static final int EVENT_UNCOMPRESSED_STRIP = 4; |
| /** |
| * When there is nothing more to parse. |
| */ |
| public static final int EVENT_END = 5; |
| |
| /** |
| * Option bit to request to parse IFD0. |
| */ |
| public static final int OPTION_IFD_0 = 1 << 0; |
| /** |
| * Option bit to request to parse IFD1. |
| */ |
| public static final int OPTION_IFD_1 = 1 << 1; |
| /** |
| * Option bit to request to parse Exif-IFD. |
| */ |
| public static final int OPTION_IFD_EXIF = 1 << 2; |
| /** |
| * Option bit to request to parse GPS-IFD. |
| */ |
| public static final int OPTION_IFD_GPS = 1 << 3; |
| /** |
| * Option bit to request to parse Interoperability-IFD. |
| */ |
| public static final int OPTION_IFD_INTEROPERABILITY = 1 << 4; |
| /** |
| * Option bit to request to parse thumbnail. |
| */ |
| public static final int OPTION_THUMBNAIL = 1 << 5; |
| |
| private static final int EXIF_HEADER = 0x45786966; // EXIF header "Exif" |
| private static final short EXIF_HEADER_TAIL = (short) 0x0000; // EXIF header in APP1 |
| |
| // TIFF header |
| private static final short LITTLE_ENDIAN_TAG = (short) 0x4949; // "II" |
| private static final short BIG_ENDIAN_TAG = (short) 0x4d4d; // "MM" |
| private static final short TIFF_HEADER_TAIL = 0x002A; |
| |
| private static final int TAG_SIZE = 12; |
| private static final int OFFSET_SIZE = 2; |
| |
| private final CountedDataInputStream mTiffStream; |
| private final int mOptions; |
| private int mIfdStartOffset = 0; |
| private int mNumOfTagInIfd = 0; |
| private int mIfdType; |
| private ExifTag mTag; |
| private ImageEvent mImageEvent; |
| private int mStripCount; |
| private ExifTag mStripSizeTag; |
| private ExifTag mJpegSizeTag; |
| private boolean mNeedToParseOffsetsInCurrentIfd; |
| private boolean mContainExifData = false; |
| |
| private final TreeMap<Integer, Object> mCorrespondingEvent = new TreeMap<Integer, Object>(); |
| |
| private boolean isIfdRequested(int ifdType) { |
| switch (ifdType) { |
| case IfdId.TYPE_IFD_0: |
| return (mOptions & OPTION_IFD_0) != 0; |
| case IfdId.TYPE_IFD_1: |
| return (mOptions & OPTION_IFD_1) != 0; |
| case IfdId.TYPE_IFD_EXIF: |
| return (mOptions & OPTION_IFD_EXIF) != 0; |
| case IfdId.TYPE_IFD_GPS: |
| return (mOptions & OPTION_IFD_GPS) != 0; |
| case IfdId.TYPE_IFD_INTEROPERABILITY: |
| return (mOptions & OPTION_IFD_INTEROPERABILITY) != 0; |
| } |
| return false; |
| } |
| |
| private boolean isThumbnailRequested() { |
| return (mOptions & OPTION_THUMBNAIL) != 0; |
| } |
| |
| private ExifParser(InputStream inputStream, int options) |
| throws IOException, ExifInvalidFormatException { |
| mContainExifData = seekTiffData(inputStream); |
| mTiffStream = new CountedDataInputStream(inputStream); |
| mOptions = options; |
| if (!mContainExifData) return; |
| if (mTiffStream.getReadByteCount() == 0) { |
| parseTiffHeader(); |
| long offset = mTiffStream.readUnsignedInt(); |
| registerIfd(IfdId.TYPE_IFD_0, offset); |
| } |
| } |
| |
| /** |
| * Parses the the given InputStream with the given options |
| * @exception IOException |
| * @exception ExifInvalidFormatException |
| */ |
| public static ExifParser parse(InputStream inputStream, int options) |
| throws IOException, ExifInvalidFormatException { |
| return new ExifParser(inputStream, options); |
| } |
| |
| /** |
| * Parses the the given InputStream with default options; that is, every IFD and thumbnaill |
| * will be parsed. |
| * @exception IOException |
| * @exception ExifInvalidFormatException |
| * @see #parse(InputStream, int) |
| */ |
| public static ExifParser parse(InputStream inputStream) |
| throws IOException, ExifInvalidFormatException { |
| return new ExifParser(inputStream, OPTION_IFD_0 | OPTION_IFD_1 |
| | OPTION_IFD_EXIF | OPTION_IFD_GPS | OPTION_IFD_INTEROPERABILITY |
| | OPTION_THUMBNAIL); |
| } |
| |
| /** |
| * Moves the parser forward and returns the next parsing event |
| * |
| * @exception IOException |
| * @exception ExifInvalidFormatException |
| * @see #EVENT_START_OF_IFD |
| * @see #EVENT_NEW_TAG |
| * @see #EVENT_VALUE_OF_REGISTERED_TAG |
| * @see #EVENT_COMPRESSED_IMAGE |
| * @see #EVENT_UNCOMPRESSED_STRIP |
| * @see #EVENT_END |
| */ |
| public int next() throws IOException, ExifInvalidFormatException { |
| if (!mContainExifData) { |
| return EVENT_END; |
| } |
| int offset = mTiffStream.getReadByteCount(); |
| int endOfTags = mIfdStartOffset + OFFSET_SIZE + TAG_SIZE * mNumOfTagInIfd; |
| if (offset < endOfTags) { |
| mTag = readTag(); |
| if (mNeedToParseOffsetsInCurrentIfd) { |
| checkOffsetOrImageTag(mTag); |
| } |
| return EVENT_NEW_TAG; |
| } else if (offset == endOfTags) { |
| long ifdOffset = readUnsignedLong(); |
| // There is a link to ifd1 at the end of ifd0 |
| if (mIfdType == IfdId.TYPE_IFD_0) { |
| if (isIfdRequested(IfdId.TYPE_IFD_1) || isThumbnailRequested()) { |
| if (ifdOffset != 0) { |
| registerIfd(IfdId.TYPE_IFD_1, ifdOffset); |
| } |
| } |
| } else { |
| if (ifdOffset != 0) { |
| throw new ExifInvalidFormatException("Invalid link to next IFD"); |
| } |
| } |
| } |
| while(mCorrespondingEvent.size() != 0) { |
| Entry<Integer, Object> entry = mCorrespondingEvent.pollFirstEntry(); |
| Object event = entry.getValue(); |
| skipTo(entry.getKey()); |
| if (event instanceof IfdEvent) { |
| mIfdType = ((IfdEvent) event).ifd; |
| mNumOfTagInIfd = mTiffStream.readUnsignedShort(); |
| mIfdStartOffset = entry.getKey(); |
| mNeedToParseOffsetsInCurrentIfd = needToParseOffsetsInCurrentIfd(); |
| if (((IfdEvent) event).isRequested) { |
| return EVENT_START_OF_IFD; |
| } else { |
| skipRemainingTagsInCurrentIfd(); |
| } |
| } else if (event instanceof ImageEvent) { |
| mImageEvent = (ImageEvent) event; |
| return mImageEvent.type; |
| } else { |
| ExifTagEvent tagEvent = (ExifTagEvent) event; |
| mTag = tagEvent.tag; |
| if (mTag.getDataType() != ExifTag.TYPE_UNDEFINED) { |
| readFullTagValue(mTag); |
| checkOffsetOrImageTag(mTag); |
| } |
| if (tagEvent.isRequested) { |
| return EVENT_VALUE_OF_REGISTERED_TAG; |
| } |
| } |
| } |
| return EVENT_END; |
| } |
| |
| /** |
| * Skips the tags area of current IFD, if the parser is not in the tag area, nothing will |
| * happen. |
| * |
| * @throws IOException |
| * @throws ExifInvalidFormatException |
| */ |
| public void skipRemainingTagsInCurrentIfd() throws IOException, ExifInvalidFormatException { |
| int endOfTags = mIfdStartOffset + OFFSET_SIZE + TAG_SIZE * mNumOfTagInIfd; |
| int offset = mTiffStream.getReadByteCount(); |
| if (offset > endOfTags) return; |
| if (mNeedToParseOffsetsInCurrentIfd) { |
| while (offset < endOfTags) { |
| mTag = readTag(); |
| checkOffsetOrImageTag(mTag); |
| offset += TAG_SIZE; |
| } |
| } else { |
| skipTo(endOfTags); |
| } |
| long ifdOffset = readUnsignedLong(); |
| // For ifd0, there is a link to ifd1 in the end of all tags |
| if (mIfdType == IfdId.TYPE_IFD_0 |
| && (isIfdRequested(IfdId.TYPE_IFD_1) || isThumbnailRequested())) { |
| if (ifdOffset > 0) { |
| registerIfd(IfdId.TYPE_IFD_1, ifdOffset); |
| } |
| } |
| } |
| |
| private boolean needToParseOffsetsInCurrentIfd() { |
| switch (mIfdType) { |
| case IfdId.TYPE_IFD_0: |
| return isIfdRequested(IfdId.TYPE_IFD_EXIF) || isIfdRequested(IfdId.TYPE_IFD_GPS) |
| || isIfdRequested(IfdId.TYPE_IFD_INTEROPERABILITY); |
| case IfdId.TYPE_IFD_1: |
| return isThumbnailRequested(); |
| case IfdId.TYPE_IFD_EXIF: |
| // The offset to interoperability IFD is located in Exif IFD |
| return isIfdRequested(IfdId.TYPE_IFD_INTEROPERABILITY); |
| default: |
| return false; |
| } |
| } |
| |
| /** |
| * If {@link #next()} return {@link #EVENT_NEW_TAG} or {@link #EVENT_VALUE_OF_REGISTERED_TAG}, |
| * call this function to get the corresponding tag. |
| * <p> |
| * |
| * For {@link #EVENT_NEW_TAG}, the tag may not contain the value if the size of the value is |
| * greater than 4 bytes. One should call {@link ExifTag#hasValue()} to check if the tag |
| * contains value. |
| * If there is no value,call {@link #registerForTagValue(ExifTag)} to have the parser emit |
| * {@link #EVENT_VALUE_OF_REGISTERED_TAG} when it reaches the area pointed by the offset. |
| * |
| * <p> |
| * When {@link #EVENT_VALUE_OF_REGISTERED_TAG} is emitted, the value of the tag will have |
| * already been read except for tags of undefined type. For tags of undefined type, call |
| * one of the read methods to get the value. |
| * |
| * @see #registerForTagValue(ExifTag) |
| * @see #read(byte[]) |
| * @see #read(byte[], int, int) |
| * @see #readLong() |
| * @see #readRational() |
| * @see #readShort() |
| * @see #readString(int) |
| * @see #readString(int, Charset) |
| */ |
| public ExifTag getTag() { |
| return mTag; |
| } |
| |
| /** |
| * Gets number of tags in the current IFD area. |
| */ |
| public int getTagCountInCurrentIfd() { |
| return mNumOfTagInIfd; |
| } |
| |
| /** |
| * Gets the ID of current IFD. |
| * |
| * @see IfdId#TYPE_IFD_0 |
| * @see IfdId#TYPE_IFD_1 |
| * @see IfdId#TYPE_IFD_GPS |
| * @see IfdId#TYPE_IFD_INTEROPERABILITY |
| * @see IfdId#TYPE_IFD_EXIF |
| */ |
| public int getCurrentIfd() { |
| return mIfdType; |
| } |
| |
| /** |
| * When receiving {@link #EVENT_UNCOMPRESSED_STRIP}, |
| * call this function to get the index of this strip. |
| * @see #getStripCount() |
| */ |
| public int getStripIndex() { |
| return mImageEvent.stripIndex; |
| } |
| |
| /** |
| * When receiving {@link #EVENT_UNCOMPRESSED_STRIP}, call this function to get the number |
| * of strip data. |
| * @see #getStripIndex() |
| */ |
| public int getStripCount() { |
| return mStripCount; |
| } |
| |
| /** |
| * When receiving {@link #EVENT_UNCOMPRESSED_STRIP}, call this function to get the strip size. |
| */ |
| public int getStripSize() { |
| if (mStripSizeTag == null) return 0; |
| if (mStripSizeTag.getDataType() == ExifTag.TYPE_UNSIGNED_SHORT) { |
| return mStripSizeTag.getUnsignedShort(mImageEvent.stripIndex); |
| } else { |
| // Cast unsigned int to int since the strip size is always smaller |
| // than the size of APP1 (65536) |
| return (int) mStripSizeTag.getUnsignedLong(mImageEvent.stripIndex); |
| } |
| } |
| |
| /** |
| * When receiving {@link #EVENT_COMPRESSED_IMAGE}, call this function to get the image data |
| * size. |
| */ |
| public int getCompressedImageSize() { |
| if (mJpegSizeTag == null) return 0; |
| // Cast unsigned int to int since the thumbnail is always smaller |
| // than the size of APP1 (65536) |
| return (int) mJpegSizeTag.getUnsignedLong(0); |
| } |
| |
| private void skipTo(int offset) throws IOException { |
| mTiffStream.skipTo(offset); |
| while (!mCorrespondingEvent.isEmpty() && mCorrespondingEvent.firstKey() < offset) { |
| mCorrespondingEvent.pollFirstEntry(); |
| } |
| } |
| |
| /** |
| * When getting {@link #EVENT_NEW_TAG} in the tag area of IFD, |
| * the tag may not contain the value if the size of the value is greater than 4 bytes. |
| * When the value is not available here, call this method so that the parser will emit |
| * {@link #EVENT_VALUE_OF_REGISTERED_TAG} when it reaches the area where the value is located. |
| |
| * @see #EVENT_VALUE_OF_REGISTERED_TAG |
| */ |
| public void registerForTagValue(ExifTag tag) { |
| mCorrespondingEvent.put(tag.getOffset(), new ExifTagEvent(tag, true)); |
| } |
| |
| private void registerIfd(int ifdType, long offset) { |
| // Cast unsigned int to int since the offset is always smaller |
| // than the size of APP1 (65536) |
| mCorrespondingEvent.put((int) offset, new IfdEvent(ifdType, isIfdRequested(ifdType))); |
| } |
| |
| private void registerCompressedImage(long offset) { |
| mCorrespondingEvent.put((int) offset, new ImageEvent(EVENT_COMPRESSED_IMAGE)); |
| } |
| |
| private void registerUncompressedStrip(int stripIndex, long offset) { |
| mCorrespondingEvent.put((int) offset, new ImageEvent(EVENT_UNCOMPRESSED_STRIP |
| , stripIndex)); |
| } |
| |
| private ExifTag readTag() throws IOException, ExifInvalidFormatException { |
| short tagId = mTiffStream.readShort(); |
| short dataFormat = mTiffStream.readShort(); |
| long numOfComp = mTiffStream.readUnsignedInt(); |
| if (numOfComp > Integer.MAX_VALUE) { |
| throw new ExifInvalidFormatException( |
| "Number of component is larger then Integer.MAX_VALUE"); |
| } |
| ExifTag tag = new ExifTag(tagId, dataFormat, (int) numOfComp, mIfdType); |
| int dataSize = tag.getDataSize(); |
| if (dataSize > 4) { |
| long offset = mTiffStream.readUnsignedInt(); |
| if (offset > Integer.MAX_VALUE) { |
| throw new ExifInvalidFormatException( |
| "offset is larger then Integer.MAX_VALUE"); |
| } |
| tag.setOffset((int) offset); |
| } else { |
| readFullTagValue(tag); |
| mTiffStream.skip(4 - dataSize); |
| } |
| return tag; |
| } |
| |
| /** |
| * Check the tag, if the tag is one of the offset tag that points to the IFD or image the |
| * caller is interested in, register the IFD or image. |
| */ |
| private void checkOffsetOrImageTag(ExifTag tag) { |
| switch (tag.getTagId()) { |
| case ExifTag.TAG_EXIF_IFD: |
| if (isIfdRequested(IfdId.TYPE_IFD_EXIF) |
| || isIfdRequested(IfdId.TYPE_IFD_INTEROPERABILITY)) { |
| registerIfd(IfdId.TYPE_IFD_EXIF, tag.getUnsignedLong(0)); |
| } |
| break; |
| case ExifTag.TAG_GPS_IFD: |
| if (isIfdRequested(IfdId.TYPE_IFD_GPS)) { |
| registerIfd(IfdId.TYPE_IFD_GPS, tag.getUnsignedLong(0)); |
| } |
| break; |
| case ExifTag.TAG_INTEROPERABILITY_IFD: |
| if (isIfdRequested(IfdId.TYPE_IFD_INTEROPERABILITY)) { |
| registerIfd(IfdId.TYPE_IFD_INTEROPERABILITY, tag.getUnsignedLong(0)); |
| } |
| break; |
| case ExifTag.TAG_JPEG_INTERCHANGE_FORMAT: |
| if (isThumbnailRequested()) { |
| registerCompressedImage(tag.getUnsignedLong(0)); |
| } |
| break; |
| case ExifTag.TAG_JPEG_INTERCHANGE_FORMAT_LENGTH: |
| if (isThumbnailRequested()) { |
| mJpegSizeTag = tag; |
| } |
| break; |
| case ExifTag.TAG_STRIP_OFFSETS: |
| if (isThumbnailRequested()) { |
| if (tag.hasValue()) { |
| for (int i = 0; i < tag.getComponentCount(); i++) { |
| if (tag.getDataType() == ExifTag.TYPE_UNSIGNED_SHORT) { |
| registerUncompressedStrip(i, tag.getUnsignedShort(i)); |
| } else { |
| registerUncompressedStrip(i, tag.getUnsignedLong(i)); |
| } |
| } |
| } else { |
| mCorrespondingEvent.put(tag.getOffset(), new ExifTagEvent(tag, false)); |
| } |
| } |
| break; |
| case ExifTag.TAG_STRIP_BYTE_COUNTS: |
| if (isThumbnailRequested()) { |
| if (tag.hasValue()) { |
| mStripSizeTag = tag; |
| } |
| } |
| break; |
| } |
| } |
| |
| private void readFullTagValue(ExifTag tag) throws IOException { |
| switch(tag.getDataType()) { |
| case ExifTag.TYPE_UNSIGNED_BYTE: |
| case ExifTag.TYPE_UNDEFINED: |
| { |
| byte buf[] = new byte[tag.getComponentCount()]; |
| read(buf); |
| tag.setValue(buf); |
| } |
| break; |
| case ExifTag.TYPE_ASCII: |
| tag.setValue(readString(tag.getComponentCount())); |
| break; |
| case ExifTag.TYPE_UNSIGNED_LONG: |
| { |
| long value[] = new long[tag.getComponentCount()]; |
| for (int i = 0, n = value.length; i < n; i++) { |
| value[i] = readUnsignedLong(); |
| } |
| tag.setValue(value); |
| } |
| break; |
| case ExifTag.TYPE_UNSIGNED_RATIONAL: |
| { |
| Rational value[] = new Rational[tag.getComponentCount()]; |
| for (int i = 0, n = value.length; i < n; i++) { |
| value[i] = readUnsignedRational(); |
| } |
| tag.setValue(value); |
| } |
| break; |
| case ExifTag.TYPE_UNSIGNED_SHORT: |
| { |
| int value[] = new int[tag.getComponentCount()]; |
| for (int i = 0, n = value.length; i < n; i++) { |
| value[i] = readUnsignedShort(); |
| } |
| tag.setValue(value); |
| } |
| break; |
| case ExifTag.TYPE_LONG: |
| { |
| int value[] = new int[tag.getComponentCount()]; |
| for (int i = 0, n = value.length; i < n; i++) { |
| value[i] = readLong(); |
| } |
| tag.setValue(value); |
| } |
| break; |
| case ExifTag.TYPE_RATIONAL: |
| { |
| Rational value[] = new Rational[tag.getComponentCount()]; |
| for (int i = 0, n = value.length; i < n; i++) { |
| value[i] = readRational(); |
| } |
| tag.setValue(value); |
| } |
| break; |
| } |
| } |
| |
| private void parseTiffHeader() throws IOException, |
| ExifInvalidFormatException { |
| short byteOrder = mTiffStream.readShort(); |
| ByteOrder order; |
| if (LITTLE_ENDIAN_TAG == byteOrder) { |
| mTiffStream.setByteOrder(ByteOrder.LITTLE_ENDIAN); |
| } else if (BIG_ENDIAN_TAG == byteOrder) { |
| mTiffStream.setByteOrder(ByteOrder.BIG_ENDIAN); |
| } else { |
| throw new ExifInvalidFormatException("Invalid TIFF header"); |
| } |
| |
| if (mTiffStream.readShort() != TIFF_HEADER_TAIL) { |
| throw new ExifInvalidFormatException("Invalid TIFF header"); |
| } |
| } |
| |
| private boolean seekTiffData(InputStream inputStream) throws IOException, |
| ExifInvalidFormatException { |
| DataInputStream dataStream = new DataInputStream(inputStream); |
| |
| // SOI and APP1 |
| if (dataStream.readShort() != JpegHeader.SOI) { |
| throw new ExifInvalidFormatException("Invalid JPEG format"); |
| } |
| |
| short marker = dataStream.readShort(); |
| while(marker != JpegHeader.APP1 && marker != JpegHeader.EOI |
| && !JpegHeader.isSofMarker(marker)) { |
| int length = dataStream.readUnsignedShort(); |
| if ((length - 2) != dataStream.skip(length - 2)) { |
| throw new EOFException(); |
| } |
| marker = dataStream.readShort(); |
| } |
| |
| if (marker != JpegHeader.APP1) return false; // No APP1 segment |
| |
| // APP1 length, it's not used for us |
| dataStream.readShort(); |
| |
| // Exif header |
| return (dataStream.readInt() == EXIF_HEADER |
| && dataStream.readShort() == EXIF_HEADER_TAIL); |
| } |
| |
| /** |
| * Reads bytes from the InputStream. |
| */ |
| public int read(byte[] buffer, int offset, int length) throws IOException { |
| return mTiffStream.read(buffer, offset, length); |
| } |
| |
| /** |
| * Equivalent to read(buffer, 0, buffer.length). |
| */ |
| public int read(byte[] buffer) throws IOException { |
| return mTiffStream.read(buffer); |
| } |
| |
| /** |
| * Reads a String from the InputStream with UTF8 charset. |
| * This is used for reading values of type {@link ExifTag#TYPE_ASCII}. |
| */ |
| public String readString(int n) throws IOException { |
| if (n > 0) { |
| byte[] buf = new byte[n]; |
| mTiffStream.readOrThrow(buf); |
| return new String(buf, 0, n - 1, "UTF8"); |
| } else { |
| return ""; |
| } |
| } |
| |
| /** |
| * Reads a String from the InputStream with the given charset. |
| * This is used for reading values of type {@link ExifTag#TYPE_ASCII}. |
| */ |
| public String readString(int n, Charset charset) throws IOException { |
| byte[] buf = new byte[n]; |
| mTiffStream.readOrThrow(buf); |
| return new String(buf, 0, n - 1, charset); |
| } |
| |
| /** |
| * Reads value of type {@link ExifTag#TYPE_UNSIGNED_SHORT} from the InputStream. |
| */ |
| public int readUnsignedShort() throws IOException { |
| return mTiffStream.readShort() & 0xffff; |
| } |
| |
| /** |
| * Reads value of type {@link ExifTag#TYPE_UNSIGNED_LONG} from the InputStream. |
| */ |
| public long readUnsignedLong() throws IOException { |
| return readLong() & 0xffffffffL; |
| } |
| |
| /** |
| * Reads value of type {@link ExifTag#TYPE_UNSIGNED_RATIONAL} from the InputStream. |
| */ |
| public Rational readUnsignedRational() throws IOException { |
| long nomi = readUnsignedLong(); |
| long denomi = readUnsignedLong(); |
| return new Rational(nomi, denomi); |
| } |
| |
| /** |
| * Reads value of type {@link ExifTag#TYPE_LONG} from the InputStream. |
| */ |
| public int readLong() throws IOException { |
| return mTiffStream.readInt(); |
| } |
| |
| /** |
| * Reads value of type {@link ExifTag#TYPE_RATIONAL} from the InputStream. |
| */ |
| public Rational readRational() throws IOException { |
| int nomi = readLong(); |
| int denomi = readLong(); |
| return new Rational(nomi, denomi); |
| } |
| |
| private static class ImageEvent { |
| int stripIndex; |
| int type; |
| ImageEvent(int type) { |
| this.stripIndex = 0; |
| this.type = type; |
| } |
| ImageEvent(int type, int stripIndex) { |
| this.type = type; |
| this.stripIndex = stripIndex; |
| } |
| } |
| |
| private static class IfdEvent { |
| int ifd; |
| boolean isRequested; |
| IfdEvent(int ifd, boolean isInterestedIfd) { |
| this.ifd = ifd; |
| this.isRequested = isInterestedIfd; |
| } |
| } |
| |
| private static class ExifTagEvent { |
| ExifTag tag; |
| boolean isRequested; |
| ExifTagEvent(ExifTag tag, boolean isRequireByUser) { |
| this.tag = tag; |
| this.isRequested = isRequireByUser; |
| } |
| } |
| |
| /** |
| * Gets the byte order of the current InputStream. |
| */ |
| public ByteOrder getByteOrder() { |
| return mTiffStream.getByteOrder(); |
| } |
| } |