content: package org.apache.lucene.analysis;
  
  /**
   * Licensed to the Apache Software Foundation (ASF) under one or more
   * contributor license agreements.  See the NOTICE file distributed with
   * this work for additional information regarding copyright ownership.
   * The ASF licenses this file to You 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.
   */
  
  /*
  
     Porter stemmer in Java. The original paper is in
  
         Porter, 1980, An algorithm for suffix stripping, Program, Vol. 14,
         no. 3, pp 130-137,
  
     See also http://www.tartarus.org/~martin/PorterStemmer/index.html
  
     Bug 1 (reported by Gonzalo Parra 16/10/99) fixed as marked below.
     Tthe words 'aed', 'eed', 'oed' leave k at 'a' for step 3, and b[k-1]
     is then out outside the bounds of b.
  
     Similarly,
  
     Bug 2 (reported by Steve Dyrdahl 22/2/00) fixed as marked below.
     'ion' by itself leaves j = -1 in the test for 'ion' in step 5, and
     b[j] is then outside the bounds of b.
  
     Release 3.
  
     [ This version is derived from Release 3, modified by Brian Goetz to
       optimize for fewer object creations.  ]
  
  */
  
  
  import java.io.IOException;
  import java.io.InputStream;
  import java.io.FileInputStream;
  
  import static org.apache.lucene.util.RamUsageEstimator.NUM_BYTES_CHAR;
  import org.apache.lucene.util.ArrayUtil;
  
  /**
   *
   * Stemmer, implementing the Porter Stemming Algorithm
   *
   * The Stemmer class transforms a word into its root form.  The input
   * word can be provided a character at time (by calling add()), or at once
   * by calling one of the various stem(something) methods.
   */
  
  class PorterStemmer
  {
    private char[] b;
    private int i,    /* offset into b */
      j, k, k0;
    private boolean dirty = false;
    private static final int INITIAL_SIZE = 50;
  
    public PorterStemmer() {
      b = new char[INITIAL_SIZE];
      i = 0;
    }
  
    /**
     * reset() resets the stemmer so it can stem another word.  If you invoke
     * the stemmer by calling add(char) and then stem(), you must call reset()
     * before starting another word.
     */
    public void reset() { i = 0; dirty = false; }
  
    /**
     * Add a character to the word being stemmed.  When you are finished
     * adding characters, you can call stem(void) to process the word.
     */
    public void add(char ch) {
      if (b.length <= i) {
        b = ArrayUtil.grow(b, i+1);
      }
      b[i++] = ch;
    }
  
    /**
     * After a word has been stemmed, it can be retrieved by toString(),
     * or a reference to the internal buffer can be retrieved by getResultBuffer
     * and getResultLength (which is generally more efficient.)
     */
    @Override
    public String toString() { return new String(b,0,i); }
  
    /**
     * Returns the length of the word resulting from the stemming process.
     */
    public int getResultLength() { return i; }
  
    /**
     * Returns a reference to a character buffer containing the results of
     * the stemming process.  You also need to consult getResultLength()
     * to determine the length of the result.
     */
    public char[] getResultBuffer() { return b; }
  
    /* cons(i) is true <=> b[i] is a consonant. */
  
    private final boolean cons(int i) {
      switch (b[i]) {
      case 'a': case 'e': case 'i': case 'o': case 'u':
        return false;
      case 'y':
        return (i==k0) ? true : !cons(i-1);
      default:
        return true;
      }
    }
  
    /* m() measures the number of consonant sequences between k0 and j. if c is
       a consonant sequence and v a vowel sequence, and <..> indicates arbitrary
       presence,
  
            <c><v>       gives 0
            <c>vc<v>     gives 1
            <c>vcvc<v>   gives 2
            <c>vcvcvc<v> gives 3
            ....
    */
  
    private final int m() {
      int n = 0;
      int i = k0;
      while(true) {
        if (i > j)
          return n;
        if (! cons(i))
          break;
        i++;
      }
      i++;
      while(true) {
        while(true) {
          if (i > j)
            return n;
          if (cons(i))
            break;
          i++;
        }
        i++;
        n++;
        while(true) {
          if (i > j)
            return n;
          if (! cons(i))
            break;
          i++;
        }
        i++;
      }
    }
  
    /* vowelinstem() is true <=> k0,...j contains a vowel */
  
    private final boolean vowelinstem() {
      int i;
      for (i = k0; i <= j; i++)
        if (! cons(i))
          return true;
      return false;
    }
  
    /* doublec(j) is true <=> j,(j-1) contain a double consonant. */
  
    private final boolean doublec(int j) {
      if (j < k0+1)
        return false;
      if (b[j] != b[j-1])
        return false;
      return cons(j);
    }
  
    /* cvc(i) is true <=> i-2,i-1,i has the form consonant - vowel - consonant
       and also if the second c is not w,x or y. this is used when trying to
       restore an e at the end of a short word. e.g.
  
            cav(e), lov(e), hop(e), crim(e), but
            snow, box, tray.
  
    */
  
    private final boolean cvc(int i) {
      if (i < k0+2 || !cons(i) || cons(i-1) || !cons(i-2))
        return false;
      else {
        int ch = b[i];
        if (ch == 'w' || ch == 'x' || ch == 'y') return false;
      }
      return true;
    }
  
    private final boolean ends(String s) {
      int l = s.length();
      int o = k-l+1;
      if (o < k0)
        return false;
      for (int i = 0; i < l; i++)
        if (b[o+i] != s.charAt(i))
          return false;
      j = k-l;
      return true;
    }
  
    /* setto(s) sets (j+1),...k to the characters in the string s, readjusting
       k. */
  
    void setto(String s) {
      int l = s.length();
      int o = j+1;
      for (int i = 0; i < l; i++)
        b[o+i] = s.charAt(i);
      k = j+l;
      dirty = true;
    }
  
    /* r(s) is used further down. */
  
    void r(String s) { if (m() > 0) setto(s); }
  
    /* step1() gets rid of plurals and -ed or -ing. e.g.
  
             caresses  ->  caress
             ponies    ->  poni
             ties      ->  ti
             caress    ->  caress
             cats      ->  cat
  
             feed      ->  feed
             agreed    ->  agree
             disabled  ->  disable
  
             matting   ->  mat
             mating    ->  mate
             meeting   ->  meet
             milling   ->  mill
             messing   ->  mess
  
             meetings  ->  meet
  
    */
  
    private final void step1() {
      if (b[k] == 's') {
        if (ends("sses")) k -= 2;
        else if (ends("ies")) setto("i");
        else if (b[k-1] != 's') k--;
      }
      if (ends("eed")) {
        if (m() > 0)
          k--;
      }
      else if ((ends("ed") || ends("ing")) && vowelinstem()) {
        k = j;
        if (ends("at")) setto("ate");
        else if (ends("bl")) setto("ble");
        else if (ends("iz")) setto("ize");
        else if (doublec(k)) {
          int ch = b[k--];
          if (ch == 'l' || ch == 's' || ch == 'z')
            k++;
        }
        else if (m() == 1 && cvc(k))
          setto("e");
      }
    }
  
    /* step2() turns terminal y to i when there is another vowel in the stem. */
  
    private final void step2() {
      if (ends("y") && vowelinstem()) {
        b[k] = 'i';
        dirty = true;
      }
    }
  
    /* step3() maps double suffices to single ones. so -ization ( = -ize plus
       -ation) maps to -ize etc. note that the string before the suffix must give
       m() > 0. */
  
    private final void step3() {
      if (k == k0) return; /* For Bug 1 */
      switch (b[k-1]) {
      case 'a':
        if (ends("ational")) { r("ate"); break; }
        if (ends("tional")) { r("tion"); break; }
        break;
      case 'c':
        if (ends("enci")) { r("ence"); break; }
        if (ends("anci")) { r("ance"); break; }
        break;
      case 'e':
        if (ends("izer")) { r("ize"); break; }
        break;
      case 'l':
        if (ends("bli")) { r("ble"); break; }
        if (ends("alli")) { r("al"); break; }
        if (ends("entli")) { r("ent"); break; }
        if (ends("eli")) { r("e"); break; }
        if (ends("ousli")) { r("ous"); break; }
        break;
      case 'o':
        if (ends("ization")) { r("ize"); break; }
        if (ends("ation")) { r("ate"); break; }
        if (ends("ator")) { r("ate"); break; }
        break;
      case 's':
        if (ends("alism")) { r("al"); break; }
        if (ends("iveness")) { r("ive"); break; }
        if (ends("fulness")) { r("ful"); break; }
        if (ends("ousness")) { r("ous"); break; }
        break;
      case 't':
        if (ends("aliti")) { r("al"); break; }
        if (ends("iviti")) { r("ive"); break; }
        if (ends("biliti")) { r("ble"); break; }
        break;
      case 'g':
        if (ends("logi")) { r("log"); break; }
      }
    }
  
    /* step4() deals with -ic-, -full, -ness etc. similar strategy to step3. */
  
    private final void step4() {
      switch (b[k]) {
      case 'e':
        if (ends("icate")) { r("ic"); break; }
        if (ends("ative")) { r(""); break; }
        if (ends("alize")) { r("al"); break; }
        break;
      case 'i':
        if (ends("iciti")) { r("ic"); break; }
        break;
      case 'l':
        if (ends("ical")) { r("ic"); break; }
        if (ends("ful")) { r(""); break; }
        break;
      case 's':
        if (ends("ness")) { r(""); break; }
        break;
      }
    }
  
    /* step5() takes off -ant, -ence etc., in context <c>vcvc<v>. */
  
    private final void step5() {
      if (k == k0) return; /* for Bug 1 */
      switch (b[k-1]) {
      case 'a':
        if (ends("al")) break;
        return;
      case 'c':
        if (ends("ance")) break;
        if (ends("ence")) break;
        return;
      case 'e':
        if (ends("er")) break; return;
      case 'i':
        if (ends("ic")) break; return;
      case 'l':
        if (ends("able")) break;
        if (ends("ible")) break; return;
      case 'n':
        if (ends("ant")) break;
        if (ends("ement")) break;
        if (ends("ment")) break;
        /* element etc. not stripped before the m */
        if (ends("ent")) break;
        return;
      case 'o':
        if (ends("ion") && j >= 0 && (b[j] == 's' || b[j] == 't')) break;
        /* j >= 0 fixes Bug 2 */
        if (ends("ou")) break;
        return;
        /* takes care of -ous */
      case 's':
        if (ends("ism")) break;
        return;
      case 't':
        if (ends("ate")) break;
        if (ends("iti")) break;
        return;
      case 'u':
        if (ends("ous")) break;
        return;
      case 'v':
        if (ends("ive")) break;
        return;
      case 'z':
        if (ends("ize")) break;
        return;
      default:
        return;
      }
      if (m() > 1)
        k = j;
    }
  
    /* step6() removes a final -e if m() > 1. */
  
    private final void step6() {
      j = k;
      if (b[k] == 'e') {
        int a = m();
        if (a > 1 || a == 1 && !cvc(k-1))
          k--;
      }
      if (b[k] == 'l' && doublec(k) && m() > 1)
        k--;
    }
  
  
    /**
     * Stem a word provided as a String.  Returns the result as a String.
     */
    public String stem(String s) {
      if (stem(s.toCharArray(), s.length()))
        return toString();
      else
        return s;
    }
  
    /** Stem a word contained in a char[].  Returns true if the stemming process
     * resulted in a word different from the input.  You can retrieve the
     * result with getResultLength()/getResultBuffer() or toString().
     */
    public boolean stem(char[] word) {
      return stem(word, word.length);
    }
  
    /** Stem a word contained in a portion of a char[] array.  Returns
     * true if the stemming process resulted in a word different from
     * the input.  You can retrieve the result with
     * getResultLength()/getResultBuffer() or toString().
     */
    public boolean stem(char[] wordBuffer, int offset, int wordLen) {
      reset();
      if (b.length < wordLen) {
        b = new char[ArrayUtil.oversize(wordLen, NUM_BYTES_CHAR)];
      }
      System.arraycopy(wordBuffer, offset, b, 0, wordLen);
      i = wordLen;
      return stem(0);
    }
  
    /** Stem a word contained in a leading portion of a char[] array.
     * Returns true if the stemming process resulted in a word different
     * from the input.  You can retrieve the result with
     * getResultLength()/getResultBuffer() or toString().
     */
    public boolean stem(char[] word, int wordLen) {
      return stem(word, 0, wordLen);
    }
  
    /** Stem the word placed into the Stemmer buffer through calls to add().
     * Returns true if the stemming process resulted in a word different
     * from the input.  You can retrieve the result with
     * getResultLength()/getResultBuffer() or toString().
     */
    public boolean stem() {
      return stem(0);
    }
  
    public boolean stem(int i0) {
      k = i - 1;
      k0 = i0;
      if (k > k0+1) {
        step1(); step2(); step3(); step4(); step5(); step6();
      }
      // Also, a word is considered dirty if we lopped off letters
      // Thanks to Ifigenia Vairelles for pointing this out.
      if (i != k+1)
        dirty = true;
      i = k+1;
      return dirty;
    }
  
    /** Test program for demonstrating the Stemmer.  It reads a file and
     * stems each word, writing the result to standard out.
     * Usage: Stemmer file-name
     */
    public static void main(String[] args) {
      PorterStemmer s = new PorterStemmer();
  
      for (int i = 0; i < args.length; i++) {
        try {
          InputStream in = new FileInputStream(args[i]);
          byte[] buffer = new byte[1024];
          int bufferLen, offset, ch;
  
          bufferLen = in.read(buffer);
          offset = 0;
          s.reset();
  
          while(true) {
            if (offset < bufferLen)
              ch = buffer[offset++];
            else {
              bufferLen = in.read(buffer);
              offset = 0;
              if (bufferLen < 0)
                ch = -1;
              else
                ch = buffer[offset++];
            }
  
            if (Character.isLetter((char) ch)) {
              s.add(Character.toLowerCase((char) ch));
            }
            else {
               s.stem();
               System.out.print(s.toString());
               s.reset();
               if (ch < 0)
                 break;
               else {
                 System.out.print((char) ch);
               }
             }
          }
  
          in.close();
        }
        catch (IOException e) {
          System.out.println("error reading " + args[i]);
        }
      }
    }
  }
  
  