package org.apache.commons.codec;

/* ====================================================================
 * The Apache Software License, Version 1.1
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 * reserved.
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 * modification, are permitted provided that the following conditions
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 *    notice, this list of conditions and the following disclaimer.
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 *       "This product includes software developed by the
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 * This software consists of voluntary contributions made by many
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/**
 * Encodes a string into a soundex value.  Sounde is an encoding used to
 * relate similar names, but can also be used as a general purpose
 * scheme to find word with similar phonemes. 
 * 
 * @todo Needs internationalisation in a future release.
 *
 * @author tobrien@transolutions.net
 * @version $Id: Soundex.java,v 1.1 2002/02/22 05:20:00 bayard Exp $
 */
public class RefinedSoundex implements Encoder {

    static public final char[] US_ENGLISH_MAPPING =
        "01360240043788015936020505".toCharArray();

    static public final RefinedSoundex US_ENGLISH = new RefinedSoundex();
    
    private char[] soundexMapping;

    public RefinedSoundex() {
        this(US_ENGLISH_MAPPING);
    }

    public RefinedSoundex(char[] mapping) {
        this.soundexMapping = mapping;
    }

    /**
     * Get the SoundEx value of a string.
     * This implementation is taken from the code-snippers on 
     * http://www.sourceforge.net/
     */
    public String soundex(String str) {
       
        StringBuffer sBuf = new StringBuffer();        
        str = str.toUpperCase();

        sBuf.append( str.charAt(0) );

        char last, mapped, current;
        last = '*';

        for( int i = 0; i < str.length(); i++ ) {

            current = getMappingCode( str.charAt(i) );
            if( current == last ) {
                continue;
            } else if( current != 0 ) {
                sBuf.append( current );   
            }
            
            last = current;             
            
        }
        
        return sBuf.toString();
    }

    public String encode(String pString) {
        return( soundex( pString ) );   
    }

    /**
     * Used internally by the SoundEx algorithm.
     */
    private char getMappingCode(char c) {
        if( !Character.isLetter(c) ) {
            return 0;
        } else {
            return soundexMapping[Character.toUpperCase(c) - 'A'];
        }
    }

}