v1/src/typeimpl/org/apache/xmlbeans/impl/regex/BMPattern.java

/*
* The Apache Software License, Version 1.1
*
*
* Copyright (c) 2003 The Apache Software Foundation.  All rights 
* reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
*    notice, this list of conditions and the following disclaimer. 
*
* 2. 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.
*
* 3. The end-user documentation included with the redistribution,
*    if any, must include the following acknowledgment:  
*       "This product includes software developed by the
*        Apache Software Foundation (http://www.apache.org/)."
*    Alternately, this acknowledgment may appear in the software itself,
*    if and wherever such third-party acknowledgments normally appear.
*
* 4. The names "Apache" and "Apache Software Foundation" must 
*    not be used to endorse or promote products derived from this
*    software without prior written permission. For written 
*    permission, please contact apache@apache.org.
*
* 5. Products derived from this software may not be called "Apache 
*    XMLBeans", nor may "Apache" appear in their name, without prior 
*    written permission of the Apache Software Foundation.
*
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED 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 APACHE SOFTWARE FOUNDATION OR
* ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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* 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.
* ====================================================================
*
* This software consists of voluntary contributions made by many
* individuals on behalf of the Apache Software Foundation and was
* originally based on software copyright (c) 2000-2003 BEA Systems 
* Inc., <http://www.bea.com/>. For more information on the Apache Software
* Foundation, please see <http://www.apache.org/>.
*/

package org.apache.xmlbeans.impl.regex;

import java.text.CharacterIterator;

/**
 * Boyer-Moore searcher.
 */
public class BMPattern {
    char[] pattern;
    int[] shiftTable;
    boolean ignoreCase;

    public BMPattern(String pat, boolean ignoreCase) {
        this(pat, 256, ignoreCase);
    }

    public BMPattern(String pat, int tableSize, boolean ignoreCase) {
        this.pattern = pat.toCharArray();
        this.shiftTable = new int[tableSize];
        this.ignoreCase = ignoreCase;

        int length = pattern.length;
        for (int i = 0;  i < this.shiftTable.length;  i ++)
            this.shiftTable[i] = length;

        for (int i = 0;  i < length;  i ++) {
            char ch = this.pattern[i];
            int diff = length-i-1;
            int index = ch % this.shiftTable.length;
            if (diff < this.shiftTable[index])
                this.shiftTable[index] = diff;
            if (this.ignoreCase) {
                ch = Character.toUpperCase(ch);
                index = ch % this.shiftTable.length;
                if (diff < this.shiftTable[index])
                    this.shiftTable[index] = diff;
                ch = Character.toLowerCase(ch);
                index = ch % this.shiftTable.length;
                if (diff < this.shiftTable[index])
                    this.shiftTable[index] = diff;
            }
        }
    }

    /**
     *
     * @return -1 if <var>iterator</var> does not contain this pattern.
     */
    public int matches(CharacterIterator iterator, int start, int limit) {
        if (this.ignoreCase)  return this.matchesIgnoreCase(iterator, start, limit);
        int plength = this.pattern.length;
        if (plength == 0)  return start;
        int index = start+plength;
        while (index <= limit) {
            int pindex = plength;
            int nindex = index+1;
            char ch;
            do {
                if ((ch = iterator.setIndex(--index)) != this.pattern[--pindex])
                    break;
                if (pindex == 0)
                    return index;
            } while (pindex > 0);
            index += this.shiftTable[ch % this.shiftTable.length]+1;
            if (index < nindex)  index = nindex;
        }
        return -1;
    }

    /**
     *
     * @return -1 if <var>str</var> does not contain this pattern.
     */
    public int matches(String str, int start, int limit) {
        if (this.ignoreCase)  return this.matchesIgnoreCase(str, start, limit);
        int plength = this.pattern.length;
        if (plength == 0)  return start;
        int index = start+plength;
        while (index <= limit) {
            //System.err.println("Starts at "+index);
            int pindex = plength;
            int nindex = index+1;
            char ch;
            do {
                if ((ch = str.charAt(--index)) != this.pattern[--pindex])
                    break;
                if (pindex == 0)
                    return index;
            } while (pindex > 0);
            index += this.shiftTable[ch % this.shiftTable.length]+1;
            if (index < nindex)  index = nindex;
        }
        return -1;
    }
    /**
     *
     * @return -1 if <var>chars</char> does not contain this pattern.
     */
    public int matches(char[] chars, int start, int limit) {
        if (this.ignoreCase)  return this.matchesIgnoreCase(chars, start, limit);
        int plength = this.pattern.length;
        if (plength == 0)  return start;
        int index = start+plength;
        while (index <= limit) {
            //System.err.println("Starts at "+index);
            int pindex = plength;
            int nindex = index+1;
            char ch;
            do {
                if ((ch = chars[--index]) != this.pattern[--pindex])
                    break;
                if (pindex == 0)
                    return index;
            } while (pindex > 0);
            index += this.shiftTable[ch % this.shiftTable.length]+1;
            if (index < nindex)  index = nindex;
        }
        return -1;
    }

    int matchesIgnoreCase(CharacterIterator iterator, int start, int limit) {
        int plength = this.pattern.length;
        if (plength == 0)  return start;
        int index = start+plength;
        while (index <= limit) {
            int pindex = plength;
            int nindex = index+1;
            char ch;
            do {
                char ch1 = ch = iterator.setIndex(--index);
                char ch2 = this.pattern[--pindex];
                if (ch1 != ch2) {
                    ch1 = Character.toUpperCase(ch1);
                    ch2 = Character.toUpperCase(ch2);
                    if (ch1 != ch2 && Character.toLowerCase(ch1) != Character.toLowerCase(ch2))
                        break;
                }
                if (pindex == 0)
                    return index;
            } while (pindex > 0);
            index += this.shiftTable[ch % this.shiftTable.length]+1;
            if (index < nindex)  index = nindex;
        }
        return -1;
    }
    
    int matchesIgnoreCase(String text, int start, int limit) {
        int plength = this.pattern.length;
        if (plength == 0)  return start;
        int index = start+plength;
        while (index <= limit) {
            int pindex = plength;
            int nindex = index+1;
            char ch;
            do {
                char ch1 = ch = text.charAt(--index);
                char ch2 = this.pattern[--pindex];
                if (ch1 != ch2) {
                    ch1 = Character.toUpperCase(ch1);
                    ch2 = Character.toUpperCase(ch2);
                    if (ch1 != ch2 && Character.toLowerCase(ch1) != Character.toLowerCase(ch2))
                        break;
                }
                if (pindex == 0)
                    return index;
            } while (pindex > 0);
            index += this.shiftTable[ch % this.shiftTable.length]+1;
            if (index < nindex)  index = nindex;
        }
        return -1;
    }
    int matchesIgnoreCase(char[] chars, int start, int limit) {
        int plength = this.pattern.length;
        if (plength == 0)  return start;
        int index = start+plength;
        while (index <= limit) {
            int pindex = plength;
            int nindex = index+1;
            char ch;
            do {
                char ch1 = ch = chars[--index];
                char ch2 = this.pattern[--pindex];
                if (ch1 != ch2) {
                    ch1 = Character.toUpperCase(ch1);
                    ch2 = Character.toUpperCase(ch2);
                    if (ch1 != ch2 && Character.toLowerCase(ch1) != Character.toLowerCase(ch2))
                        break;
                }
                if (pindex == 0)
                    return index;
            } while (pindex > 0);
            index += this.shiftTable[ch % this.shiftTable.length]+1;
            if (index < nindex)  index = nindex;
        }
        return -1;
    }

    /*
    public static void main(String[] argv) {
        try {
            int[] shiftTable = new int[256];
            initializeBoyerMoore(argv[0], shiftTable, true);
            int o = -1;
            CharacterIterator ite = new java.text.StringCharacterIterator(argv[1]);
            long start = System.currentTimeMillis();
            //for (int i = 0;  i < 10000;  i ++)
                o = searchIgnoreCasesWithBoyerMoore(ite, 0, argv[0], shiftTable);
            start = System.currentTimeMillis()-start;
            System.out.println("Result: "+o+", Elapsed: "+start);
        } catch (Exception ex) {
            ex.printStackTrace();
        }
    }*/
}