/*
 * JBoss, Home of Professional Open Source
 * Copyright 2006, JBoss Inc., and individual contributors as indicated
 * by the @authors tag. See the copyright.txt in the distribution for a
 * full listing of individual contributors.
 *
 * This is free software; you can redistribute it and/or modify it
 * under the terms of the GNU Lesser General Public License as
 * published by the Free Software Foundation; either version 2.1 of
 * the License, or (at your option) any later version.
 *
 * This software 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
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this software; if not, write to the Free
 * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
 * 02110-1301 USA, or see the FSF site: http://www.fsf.org.
 */
package org.jboss.wsf.common;

import java.util.regex.Matcher;
import java.util.regex.Pattern;

/**
 *
 * @author <a href="mailto:mvecera@redhat.com">Martin Vecera</a>
 */
final public class Normalizer {
    private static final Pattern PATTERN = Pattern.compile("[&<>'\"\r\n]");

    public static String normalize(String strValue) {
        return normalize(strValue, false);
    }

    public static String normalize(String strValue, boolean canonical) {
        Matcher m = PATTERN.matcher(strValue);
        if (m.find()) {
            int pos = m.start(); // we can use previous match to skip some part at the string beginning
            int len = strValue.length(); // just a single call to length()
            char[] input = new char[len]; // this is to ommit calls to String.charAt()
            strValue.getChars(0, len, input, 0);
            StringBuilder sb = new StringBuilder(len * 3); // faster than StringBuffer, not thread safe

            int copyStart = 0;

            for (int i = pos; i < len; i++) {
                char ch = input[i];
                switch (ch) {
                    case '<':
                        if (copyStart < i) {
                            sb.append(input, copyStart, i - copyStart);
                        }
                        copyStart = i + 1;
                        sb.append("&lt;");
                        break;
                    case '>':
                        if (copyStart < i) {
                            sb.append(input, copyStart, i - copyStart);
                        }
                        copyStart = i + 1;
                        sb.append("&gt;");
                        break;
                    case '"':
                        if (copyStart < i) {
                            sb.append(input, copyStart, i - copyStart);
                        }
                        copyStart = i + 1;
                        sb.append("&quot;");
                        break;
                    case '\'':
                        if (copyStart < i) {
                            sb.append(input, copyStart, i - copyStart);
                        }
                        copyStart = i + 1;
                        sb.append("&apos;");
                        break;
                    case '&':
                        if (copyStart < i) {
                            sb.append(input, copyStart, i - copyStart);
                        }
                        copyStart = i + 1;
                        sb.append("&amp;");
                        break;
                    case '\r':
                    case '\n':
                        if (canonical) {
                            sb.append("&#");
                            sb.append(Integer.toString(ch));
                            sb.append(';');
                            break;
                        }

                }
            }
            if (copyStart < len) {
                sb.append(input, copyStart, len - copyStart);
            }

            return sb.toString();
        } else {
            return strValue;
        }
    }
}