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/*
* 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.IOException;
import java.nio.charset.Charset;
import java.util.Map.Entry;
import java.util.TreeMap;
public class IfdParser {
private static final int TAG_SIZE = 12;
private final TiffInputStream mTiffStream;
private final int mEndOfTagOffset;
private final int mNumOfTag;
private int mNextOffset;
private int mOffsetToNextIfd = 0;
private TreeMap<Integer, ExifTag> mCorrespondingTag = new TreeMap<Integer, ExifTag>();
private ExifTag mCurrTag;
private int mCurrTagOffset;
public static final int TYPE_NEW_TAG = 0;
public static final int TYPE_VALUE_OF_PREV_TAG = 1;
public static final int TYPE_NEXT_IFD = 2;
public static final int TYPE_END = 3;
IfdParser(TiffInputStream tiffStream, int offset) throws IOException {
mTiffStream = tiffStream;
mTiffStream.skipTo(offset);
mNumOfTag = mTiffStream.readUnsignedShort();
mEndOfTagOffset = offset + mNumOfTag * TAG_SIZE + 2;
mNextOffset = offset + 2;
}
public int next() throws IOException {
int offset = mTiffStream.getReadByteCount();
if (offset < mEndOfTagOffset) {
offset = mNextOffset;
skipTo(mNextOffset);
if(mNextOffset < mEndOfTagOffset) {
mNextOffset += TAG_SIZE;
return TYPE_NEW_TAG;
}
}
if (offset == mEndOfTagOffset) {
mOffsetToNextIfd = mTiffStream.readInt();
}
if (!mCorrespondingTag.isEmpty()) {
Entry<Integer, ExifTag> entry = mCorrespondingTag.pollFirstEntry();
mCurrTag = entry.getValue();
mCurrTagOffset = entry.getKey();
skipTo(entry.getKey());
return TYPE_VALUE_OF_PREV_TAG;
} else {
if (offset <= mOffsetToNextIfd) {
skipTo(mOffsetToNextIfd);
// Reset mOffsetToNextIfd to 0 so next call to next() will point to the end
mOffsetToNextIfd = 0;
return TYPE_NEXT_IFD;
} else {
return TYPE_END;
}
}
}
public 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");
}
return new ExifTag(tagId, dataFormat, (int) numOfComp);
}
public ExifTag getCorrespodingExifTag() {
return mCurrTagOffset != mTiffStream.getReadByteCount() ? null : mCurrTag;
}
public void waitValueOfTag(ExifTag tag, long offset) {
if (offset > Integer.MAX_VALUE || offset < 0) {
throw new IllegalArgumentException(offset + " must be in 0 ~ " + Integer.MAX_VALUE);
}
mCorrespondingTag.put((int) offset, tag);
}
public void skipTo(int offset) throws IOException {
mTiffStream.skipTo(offset);
while (!mCorrespondingTag.isEmpty() && mCorrespondingTag.firstKey() < offset) {
mCorrespondingTag.pollFirstEntry();
}
}
public IfdParser parseIfdBlock() throws IOException {
return new IfdParser(mTiffStream, mTiffStream.getReadByteCount());
}
public int read(byte[] buffer, int offset, int length) throws IOException {
return mTiffStream.read(buffer, offset, length);
}
public int read(byte[] buffer) throws IOException {
return mTiffStream.read(buffer);
}
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 "";
}
}
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);
}
public int readUnsignedShort() throws IOException {
return readShort() & 0xffff;
}
public long readUnsignedInt() throws IOException {
return readInt() & 0xffffffffL;
}
public Rational readUnsignedRational() throws IOException {
long nomi = readUnsignedInt();
long denomi = readUnsignedInt();
return new Rational(nomi, denomi);
}
public int readInt() throws IOException {
return mTiffStream.readInt();
}
public short readShort() throws IOException {
return mTiffStream.readShort();
}
public Rational readRational() throws IOException {
int nomi = readInt();
int denomi = readInt();
return new Rational(nomi, denomi);
}
}
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