/* ***** BEGIN LICENSE BLOCK *****
* Version: MPL 1.1/GPL 2.0/LGPL 2.1
*
* The contents of this file are subject to the Mozilla Public License Version
* 1.1 (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.mozilla.org/MPL/
*
* Software distributed under the License is distributed on an "AS IS" basis,
* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
* for the specific language governing rights and limitations under the
* License.
*
* The Original Code is part of dcm4che, an implementation of DICOM(TM) in
* Java(TM), hosted at https://github.com/gunterze/dcm4che.
*
* The Initial Developer of the Original Code is
* Agfa Healthcare.
* Portions created by the Initial Developer are Copyright (C) 2013
* the Initial Developer. All Rights Reserved.
*
* Contributor(s):
* See @authors listed below
*
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* either the GNU General Public License Version 2 or later (the "GPL"), or
* the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
* in which case the provisions of the GPL or the LGPL are applicable instead
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* ***** END LICENSE BLOCK ***** */
package org.dcm4che3.imageio.stream;
import java.io.IOException;
import javax.imageio.stream.ImageInputStream;
import javax.imageio.stream.ImageInputStreamImpl;
import org.dcm4che3.data.BulkData;
import org.dcm4che3.data.Fragments;
/**
* @author Gunter Zeilinger <gunterze@gmail.com>
*
*/
public class SegmentedInputImageStream extends ImageInputStreamImpl {
private final ImageInputStream stream;
private final long[] segmentPositionsList;
private final int[] segmentLengths;
private int curSegment;
private long curSegmentEnd;
public SegmentedInputImageStream(ImageInputStream stream,
Fragments pixeldataFragments, int frameIndex) throws IOException {
long[] offsets = new long[pixeldataFragments.size()-(frameIndex+1)];
int[] length = new int[offsets.length];
for (int i = 0; i < length.length; i++) {
BulkData bulkData = (BulkData) pixeldataFragments.get(i+frameIndex+1);
offsets[i] = bulkData.offset;
length[i] = bulkData.length;
}
this.stream = stream;
this.segmentPositionsList = offsets;
this.segmentLengths = length;
seek(0);
}
public SegmentedInputImageStream(ImageInputStream stream,
long[] segmentPositionsList, int[] segmentLengths)
throws IOException {
this.stream = stream;
this.segmentPositionsList = segmentPositionsList.clone();
this.segmentLengths = segmentLengths.clone();
seek(0);
}
private int offsetOf(int segment) {
int pos = 0;
for (int i = 0; i < segment; ++i)
pos += segmentLengths[i];
return pos;
}
@Override
public void seek(long pos) throws IOException {
super.seek(pos);
for (int i = 0, off = 0; i < segmentLengths.length; i++) {
int end = off + segmentLengths[i];
if (pos < end) {
stream.seek(segmentPositionsList[i] + pos - off);
curSegment = i;
curSegmentEnd = end;
return;
}
off = end;
}
curSegment = -1;
}
@Override
public int read() throws IOException {
if (!prepareRead())
return -1;
bitOffset = 0;
int val = stream.read();
if (val != -1) {
++streamPos;
}
return val;
}
private boolean prepareRead() throws IOException {
if (curSegment < 0)
return false;
if (streamPos < curSegmentEnd)
return true;
if (curSegment >= segmentPositionsList.length)
return false;
seek(offsetOf(curSegment+1));
return true;
}
@Override
public int read(byte[] b, int off, int len) throws IOException {
if (!prepareRead())
return -1;
bitOffset = 0;
int nbytes = stream.read(b, off,
Math.min(len, (int) (curSegmentEnd-streamPos)));
if (nbytes != -1) {
streamPos += nbytes;
}
return nbytes;
}
}