nameparser.java

来自「proguard 一个java的混淆器」· Java 代码 · 共 107 行

/*
 * ProGuard -- shrinking, optimization, obfuscation, and preverification
 *             of Java bytecode.
 *
 * Copyright (c) 2002-2007 Eric Lafortune ([e-mail])
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by the Free
 * Software Foundation; either version 2 of the License, or (at your option)
 * any later version.
 *
 * 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 General Public License for
 * more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program; if not, write to the Free Software Foundation, Inc.,
 * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 */
package proguard.util;

/**
 * This StringParser can create StringMatcher instances for regular expressions
 * matching names. The regular expressions are interpreted as comma-separated
 * lists of names, optionally prefixed with '!' negators.
 * If a name with a negator matches, a negative match is returned, without
 * considering any subsequent entries in the list.
 * Names can contain the following wildcards:
 * '?'  for a single character, and
 * '*'  for any number of characters.
 *
 * @author Eric Lafortune
 */
public class NameParser implements StringParser
{
    // Implementations for StringParser.

    public StringMatcher parse(String regularExpression)
    {
        int           index;
        StringMatcher nextMatcher = new EmptyStringMatcher();

        // Look for wildcards.
        for (index = 0; index < regularExpression.length(); index++)
        {
            // Is there a '*' wildcard?
            if (regularExpression.charAt(index) == '*')
            {
                // Create a matcher for the wildcard and, recursively, for the
                // remainder of the string.
                nextMatcher =
                    new VariableStringMatcher(null,
                                              null,
                                              0,
                                              Integer.MAX_VALUE,
                                              parse(regularExpression.substring(index + 1)));
                break;
            }

            // Is there a '?' wildcard?
            else if (regularExpression.charAt(index) == '?')
            {
                // Create a matcher for the wildcard and, recursively, for the
                // remainder of the string.
                nextMatcher =
                    new VariableStringMatcher(null,
                                              null,
                                              1,
                                              1,
                                              parse(regularExpression.substring(index + 1)));
                break;
            }
        }

        // Return a matcher for the fixed first part of the regular expression,
        // if any, and the remainder.
        return index != 0 ?
            (StringMatcher)new FixedStringMatcher(regularExpression.substring(0, index), nextMatcher) :
            (StringMatcher)nextMatcher;
    }


    /**
     * A main method for testing name matching.
     */
    public static void main(String[] args)
    {
        try
        {
            System.out.println("Regular expression ["+args[0]+"]");
            NameParser parser  = new NameParser();
            StringMatcher  matcher = parser.parse(args[0]);
            for (int index = 1; index < args.length; index++)
            {
                String string = args[index];
                System.out.print("String             ["+string+"]");
                System.out.println(" -> match = "+matcher.matches(args[index]));
            }
        }
        catch (Exception ex)
        {
            ex.printStackTrace();
        }
    }
}