de.intarsys.pdf.st.STXRefSubsection Maven / Gradle / Ivy
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/*
* Copyright (c) 2007, intarsys consulting GmbH
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* - Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
*
* - Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
*
* - Neither the name of intarsys nor the names of its contributors may be used
* to endorse or promote products derived from this software without specific
* prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
package de.intarsys.pdf.st;
import java.util.ArrayList;
import java.util.List;
/**
* A XRef subsection in a PDF document.
*
* A XRef section consists of at least one subsection. The subsections describe
* the objects that have changed with regard to the previous document version.
*
* Each subsection contains entries for a contiguous range of objects. The
* serialized form starts with 2 number, the object number of the first entry
* and the number of entries. Following this there is one line for each entry in
* the form
*
* In Use entry: {@code
* offset[10] " " generation[5] " " n eol[2]
* }
*
* Free entry: {@code
* next free[10] " " generation[5] " " f eol[2]
* }
*/
public class STXRefSubsection {
private STXRefSubsection next;
private List entries;
private int start;
// record size for performance sake
private int size;
private STXRefSection xRefSection;
protected STXRefSubsection(int start) {
this(null, start);
}
public STXRefSubsection(STXRefSection xRefSection, int start) {
this.xRefSection = xRefSection;
this.start = start;
this.entries = new ArrayList();
this.size = 0;
}
protected void addEntry(STXRefEntry entry) {
int number = entry.getObjectNumber();
if (number < getStart()) {
throw new IllegalArgumentException("can't add object with number " + number);
}
int end = start + size;
if (start <= number && number < end) {
entries.set(number - start, entry);
return;
}
if (number == end) {
// fits to end of list
entries.add(entry);
size++;
checkNext();
return;
}
throw new IllegalArgumentException("can't add object with number " + number);
}
protected void checkNext() {
if (getNext() == null) {
return;
}
if (getSize() == 0) {
start = getNext().getStart();
mergeWithNext();
return;
}
if ((start + getSize()) == getNext().getStart()) {
mergeWithNext();
}
}
protected List getEntries() {
return entries;
}
protected STXRefEntry getEntry(int objectNumber) {
return (STXRefEntry) entries.get(objectNumber - start);
}
protected STXRefSubsection getNext() {
return next;
}
public int getSize() {
return size;
}
public int getStart() {
return start;
}
public int getStop() {
return start + getSize();
}
protected STXRefSection getXRefSection() {
return xRefSection;
}
protected boolean isInSection(int objectNumber) {
return ((objectNumber >= start) && (objectNumber < (start + getSize())));
}
protected void mergeWithNext() {
entries.addAll(getNext().getEntries());
size = entries.size();
setNext(getNext().getNext());
}
protected void setNext(STXRefSubsection next) {
this.next = next;
}
protected void setXRefSection(STXRefSection xRefSection) {
this.xRefSection = xRefSection;
}
}