com.itextpdf.layout.hyphenation.TernaryTreeIterator Maven / Gradle / Ivy
/*
This file is part of the iText (R) project.
Copyright (c) 1998-2020 iText Group NV
Authors: Bruno Lowagie, Paulo Soares, et al.
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU Affero General Public License version 3
as published by the Free Software Foundation with the addition of the
following permission added to Section 15 as permitted in Section 7(a):
FOR ANY PART OF THE COVERED WORK IN WHICH THE COPYRIGHT IS OWNED BY
ITEXT GROUP. ITEXT GROUP DISCLAIMS THE WARRANTY OF NON INFRINGEMENT
OF THIRD PARTY RIGHTS
This program is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
or FITNESS FOR A PARTICULAR PURPOSE.
See the GNU Affero General Public License for more details.
You should have received a copy of the GNU Affero General Public License
along with this program; if not, see http://www.gnu.org/licenses or write to
the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
Boston, MA, 02110-1301 USA, or download the license from the following URL:
http://itextpdf.com/terms-of-use/
The interactive user interfaces in modified source and object code versions
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Section 5 of the GNU Affero General Public License.
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You can be released from the requirements of the license by purchasing
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*/
package com.itextpdf.layout.hyphenation;
import java.util.Enumeration;
import java.util.Stack;
/**
* An object that iterates over the {@link TernaryTree}.
*/
class TernaryTreeIterator implements Enumeration {
/**
* current node index
*/
int cur;
/**
* current key
*/
String curkey;
TernaryTree tt;
private class Item {
/**
* parent
*/
char parent;
/**
* child
*/
char child;
/**
* default constructor
*/
public Item() {
parent = 0;
child = 0;
}
/**
* Construct item.
*
* @param p a char
* @param c a char
*/
public Item(char p, char c) {
parent = p;
child = c;
}
public Item(Item i) {
this.parent = i.parent;
this.child = i.child;
}
}
/**
* Node stack
*/
Stack ns;
/**
* key stack implemented with a StringBuffer
*/
StringBuffer ks;
/**
* default constructor
*/
public TernaryTreeIterator(TernaryTree tt) {
this.tt = tt;
cur = -1;
ns = new Stack();
ks = new StringBuffer();
reset();
}
/**
* Resets the Iterator to its initial state.
*/
public void reset() {
ns.removeAllElements();
ks.setLength(0);
cur = tt.root;
run();
}
/**
* @return next element
*/
public Object nextElement() {
String res = curkey;
cur = up();
run();
return res;
}
/**
* @return value
*/
public char getValue() {
if (cur >= 0) {
return tt.eq[cur];
}
return (char) 0;
}
/**
* @return true if more elements
*/
public boolean hasMoreElements() {
return (cur != -1);
}
/**
* traverse upwards
*/
private int up() {
Item i = new Item();
int res = 0;
if (ns.size() == 0) {
return -1;
}
if (cur != 0 && tt.sc[cur] == 0) {
return tt.lo[cur];
}
boolean climb = true;
while (climb) {
i = (Item) ns.pop();
i.child++;
switch (i.child) {
case (char) 1:
if (tt.sc[i.parent] != 0) {
res = tt.eq[i.parent];
ns.push(new Item(i));
ks.append(tt.sc[i.parent]);
} else {
i.child++;
ns.push(new Item(i));
res = tt.hi[i.parent];
}
climb = false;
break;
case (char) 2:
res = tt.hi[i.parent];
ns.push(new Item(i));
if (ks.length() > 0) {
// pop
ks.setLength(ks.length() - 1);
}
climb = false;
break;
default:
if (ns.size() == 0) {
return -1;
}
climb = true;
break;
}
}
return res;
}
/**
* traverse the tree to find next key
*/
private int run() {
if (cur == -1) {
return -1;
}
boolean leaf = false;
while (true) {
// first go down on low branch until leaf or compressed branch
while (cur != 0) {
if (tt.sc[cur] == 0xFFFF) {
leaf = true;
break;
}
ns.push(new Item((char) cur, '\u0000'));
if (tt.sc[cur] == 0) {
leaf = true;
break;
}
cur = tt.lo[cur];
}
if (leaf) {
break;
}
// nothing found, go up one node and try again
cur = up();
if (cur == -1) {
return -1;
}
}
// The current node should be a data node and
// the key should be in the key stack (at least partially)
StringBuffer buf = new StringBuffer(ks.toString());
if (tt.sc[cur] == 0xFFFF) {
int p = tt.lo[cur];
while (tt.kv.get(p) != 0) {
buf.append(tt.kv.get(p++));
}
}
curkey = buf.toString();
return 0;
}
}