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Egothor Software License version 1.00
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Copyright (C) 1997-2004 Leo Galambos.
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Copyright (C) 2002-2004 "Egothor developers"
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on behalf of the Egothor Project.
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This software is copyrighted by the "Egothor developers". If this
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license applies to a single file or document, the "Egothor developers"
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are the people or entities mentioned as copyright holders in that file
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or document. If this license applies to the Egothor project as a
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whole, the copyright holders are the people or entities mentioned in
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the file CREDITS. This file can be found in the same location as this
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license in the distribution.
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Redistribution and use in source and binary forms, with or without
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modification, are permitted provided that the following conditions are
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1. Redistributions of source code must retain the above copyright
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notice, the list of contributors, this list of conditions, and the
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2. Redistributions in binary form must reproduce the above copyright
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notice, the list of contributors, this list of conditions, and the
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disclaimer that follows these conditions in the documentation
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and/or other materials provided with the distribution.
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3. The name "Egothor" must not be used to endorse or promote products
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derived from this software without prior written permission. For
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written permission, please contact Leo.G@seznam.cz
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4. Products derived from this software may not be called "Egothor",
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nor may "Egothor" appear in their name, without prior written
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permission from Leo.G@seznam.cz.
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In addition, we request that you include in the end-user documentation
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provided with the redistribution and/or in the software itself an
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acknowledgement equivalent to the following:
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"This product includes software developed by the Egothor Project.
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http://egothor.sf.net/"
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THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
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WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
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MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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IN NO EVENT SHALL THE EGOTHOR PROJECT OR ITS CONTRIBUTORS BE LIABLE
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FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
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BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
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WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
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OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN
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IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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This software consists of voluntary contributions made by many
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individuals on behalf of the Egothor Project and was originally
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created by Leo Galambos (Leo.G@seznam.cz).
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package org.egothor.stemmer;
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import java.io.DataInput;
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import java.io.DataOutput;
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import java.io.IOException;
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import java.util.ArrayList;
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import java.util.List;
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* The MultiTrie is a Trie of Tries.
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* It stores words and their associated patch commands. The MultiTrie handles
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* patch commmands broken into their constituent parts, as a MultiTrie does, but
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* the commands are delimited by the skip command.
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public class MultiTrie2 extends MultiTrie {
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* Constructor for the MultiTrie object.
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* @param is the input stream
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* @exception IOException if an I/O error occurs
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public MultiTrie2(DataInput is) throws IOException {
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* Constructor for the MultiTrie2 object
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* @param forward set to <tt>true</tt> if the elements should be read left to
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public MultiTrie2(boolean forward) {
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* Return the element that is stored in a cell associated with the given key.
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* @param key the key to the cell holding the desired element
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public CharSequence getFully(CharSequence key) {
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StringBuilder result = new StringBuilder(tries.size() * 2);
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CharSequence lastkey = key;
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CharSequence p[] = new CharSequence[tries.size()];
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for (int i = 0; i < tries.size(); i++) {
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CharSequence r = tries.get(i).getFully(lastkey);
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if (r == null || (r.length() == 1 && r.charAt(0) == EOM)) {
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if (cannotFollow(lastch, r.charAt(0))) {
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lastch = r.charAt(r.length() - 2);
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// key=key.substring(lengthPP(r));
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if (p[i].charAt(0) == '-') {
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key = skip(key, lengthPP(p[i - 1]));
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key = skip(key, lengthPP(p[i]));
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// key = skip(key, lengthPP(r));
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if (key.length() != 0) {
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} catch (IndexOutOfBoundsException x) {}
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* Return the element that is stored as last on a path belonging to the given
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* @param key the key associated with the desired element
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* @return the element that is stored as last on a path
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public CharSequence getLastOnPath(CharSequence key) {
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StringBuilder result = new StringBuilder(tries.size() * 2);
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CharSequence lastkey = key;
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CharSequence p[] = new CharSequence[tries.size()];
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for (int i = 0; i < tries.size(); i++) {
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CharSequence r = tries.get(i).getLastOnPath(lastkey);
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if (r == null || (r.length() == 1 && r.charAt(0) == EOM)) {
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// System.err.println("LP:"+key+" last:"+lastch+" new:"+r);
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if (cannotFollow(lastch, r.charAt(0))) {
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lastch = r.charAt(r.length() - 2);
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// key=key.substring(lengthPP(r));
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if (p[i].charAt(0) == '-') {
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key = skip(key, lengthPP(p[i - 1]));
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key = skip(key, lengthPP(p[i]));
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// key = skip(key, lengthPP(r));
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if (key.length() != 0) {
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} catch (IndexOutOfBoundsException x) {}
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* Write this data structure to the given output stream.
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* @param os the output stream
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* @exception IOException if an I/O error occurs
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public void store(DataOutput os) throws IOException {
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* Add an element to this structure consisting of the given key and patch
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* This method will return without executing if the <tt>cmd</tt>
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* parameter's length is 0.
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* @param cmd the patch command
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public void add(CharSequence key, CharSequence cmd) {
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if (cmd.length() == 0) {
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// System.err.println( cmd );
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CharSequence p[] = decompose(cmd);
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int levels = p.length;
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// System.err.println("levels "+key+" cmd "+cmd+"|"+levels);
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while (levels >= tries.size()) {
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tries.add(new Trie(forward));
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CharSequence lastkey = key;
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for (int i = 0; i < levels; i++) {
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if (key.length() > 0) {
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tries.get(i).add(key, p[i]);
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tries.get(i).add(lastkey, p[i]);
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// System.err.println("-"+key+" "+p[i]+"|"+key.length());
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* key=key.substring(lengthPP(p[i]));
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if (p[i].length() > 0 && p[i].charAt(0) == '-') {
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key = skip(key, lengthPP(p[i - 1]));
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key = skip(key, lengthPP(p[i]));
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// System.err.println("--->"+key);
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if (key.length() > 0) {
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tries.get(levels).add(key, EOM_NODE);
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tries.get(levels).add(lastkey, EOM_NODE);
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* Break the given patch command into its constituent pieces. The pieces are
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* delimited by NOOP commands.
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* @param cmd the patch command
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* @return an array containing the pieces of the command
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public CharSequence[] decompose(CharSequence cmd) {
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for (int i = 0; 0 <= i && i < cmd.length();) {
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int next = dashEven(cmd, i);
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CharSequence part[] = new CharSequence[parts];
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for (int i = 0; 0 <= i && i < cmd.length();) {
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int next = dashEven(cmd, i);
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part[x++] = cmd.subSequence(i, i + 2);
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part[x++] = (next < 0) ? cmd.subSequence(i, cmd.length()) : cmd.subSequence(i, next);
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* Remove empty rows from the given Trie and return the newly reduced Trie.
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* @param by the Trie to reduce
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* @return the newly reduced Trie
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public Trie reduce(Reduce by) {
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List<Trie> h = new ArrayList<Trie>();
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for (Trie trie : tries)
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h.add(trie.reduce(by));
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MultiTrie2 m = new MultiTrie2(forward);
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private boolean cannotFollow(char after, char goes) {
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return after == goes;
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private CharSequence skip(CharSequence in, int count) {
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return in.subSequence(count, in.length());
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return in.subSequence(0, in.length() - count);
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private int dashEven(CharSequence in, int from) {
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while (from < in.length()) {
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if (in.charAt(from) == '-') {
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@SuppressWarnings("fallthrough")
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private int lengthPP(CharSequence cmd) {
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for (int i = 0; i < cmd.length(); i++) {
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switch (cmd.charAt(i++)) {
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len += cmd.charAt(i) - 'a' + 1;
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len++; /* intentional fallthrough */