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 * Copyright (c) 1999, 2012, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code 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
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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 */

package com.sun.jndi.toolkit.url;

import java.net.MalformedURLException;
import java.io.UnsupportedEncodingException;
import java.net.URLDecoder;

Utilities for dealing with URLs.
Author:
Vincent Ryan/**
 * Utilities for dealing with URLs.
 * @author Vincent Ryan
 */

final public class UrlUtil {

    // To prevent creation of this static class
    private UrlUtil() {
    }

    
Decode a URI string (according to RFC 2396).
/**
     * Decode a URI string (according to RFC 2396).
     */
    public static final String decode(String s) throws MalformedURLException {
        try {
            return decode(s, "8859_1");
        } catch (UnsupportedEncodingException e) {
            // ISO-Latin-1 should always be available?
            throw new MalformedURLException("ISO-Latin-1 decoder unavailable");
        }
    }

    
Decode a URI string (according to RFC 2396).
Three-character sequences '%xy', where 'xy' is the two-digit
hexadecimal representation of the lower 8-bits of a character,
are decoded into the character itself.
The string is subsequently converted using the specified encoding
/**
     * Decode a URI string (according to RFC 2396).
     *
     * Three-character sequences '%xy', where 'xy' is the two-digit
     * hexadecimal representation of the lower 8-bits of a character,
     * are decoded into the character itself.
     *
     * The string is subsequently converted using the specified encoding
     */
    public static final String decode(String s, String enc)
            throws MalformedURLException, UnsupportedEncodingException {
        try {
            return URLDecoder.decode(s, enc);
        } catch (IllegalArgumentException iae) {
            MalformedURLException mue = new MalformedURLException("Invalid URI encoding: " + s);
            mue.initCause(iae);
            throw mue;
        }
    }

    
Encode a string for inclusion in a URI (according to RFC 2396).
Unsafe characters are escaped by encoding them in three-character
sequences '%xy', where 'xy' is the two-digit hexadecimal representation
of the lower 8-bits of the character.
The question mark '?' character is also escaped, as required by RFC 2255.
The string is first converted to the specified encoding.
For LDAP (2255), the encoding must be UTF-8.
/**
     * Encode a string for inclusion in a URI (according to RFC 2396).
     *
     * Unsafe characters are escaped by encoding them in three-character
     * sequences '%xy', where 'xy' is the two-digit hexadecimal representation
     * of the lower 8-bits of the character.
     *
     * The question mark '?' character is also escaped, as required by RFC 2255.
     *
     * The string is first converted to the specified encoding.
     * For LDAP (2255), the encoding must be UTF-8.
     */
    public static final String encode(String s, String enc)
        throws UnsupportedEncodingException {

        byte[] bytes = s.getBytes(enc);
        int count = bytes.length;

        /*
         * From RFC 2396:
         *
         *     mark = "-" | "_" | "." | "!" | "~" | "*" | "'" | "(" | ")"
         * reserved = ";" | "/" | ":" | "?" | "@" | "&" | "=" | "+" | "$" | ","
         */
        final String allowed = "=,+;.'-@&/$_()!~*:"; // '?' is omitted
        char[] buf = new char[3 * count];
        int j = 0;

        for (int i = 0; i < count; i++) {
            if ((bytes[i] >= 0x61 && bytes[i] <= 0x7A) || // a..z
                (bytes[i] >= 0x41 && bytes[i] <= 0x5A) || // A..Z
                (bytes[i] >= 0x30 && bytes[i] <= 0x39) || // 0..9
                (allowed.indexOf(bytes[i]) >= 0)) {
                buf[j++] = (char) bytes[i];
            } else {
                buf[j++] = '%';
                buf[j++] = Character.forDigit(0xF & (bytes[i] >>> 4), 16);
                buf[j++] = Character.forDigit(0xF & bytes[i], 16);
            }
        }
        return new String(buf, 0, j);
    }
}