/*

* Portions copyright (c) 2009 Nokia Corporation and/or its subsidiary(-ies).

* All rights reserved.

* This component and the accompanying materials are made available

* under the terms of "Eclipse Public License v1.0"

* which accompanies this distribution, and is available

* at the URL "http://www.eclipse.org/legal/epl-v10.html".

*

* Initial Contributors:

* Nokia Corporation - initial contribution.

*

* Contributors:

*

* Description:

*

*/

package com.nokia.mj.impl.fileutils;

import java.io.ByteArrayOutputStream;

/**

 * FileUTF8Handler helps in encoding an decoding a URL given.

 */

public class FileUTF8Handler

{

    public static String decode(String iEscapedUrl)

    {

        String decoded = iEscapedUrl;

        validateUnescapedUrl(decoded);

        if (iEscapedUrl.indexOf("%") != -1)

        {

            decoded = unescape(iEscapedUrl);

        }

        return decoded;

    }

    public static String encode(String iUnescapedUrl)

    {

        try

        {

            return URLUTF8Encoder.encode(decode(iUnescapedUrl));

        }

        catch (Exception e)

        {

            // Nothing to do

        }

        return iUnescapedUrl;

    }

    private static boolean isValidHexDigit(char aChar)

    {

        if (!Character.isDigit(aChar) && !(aChar >= 'a' && aChar <= 'f')

                && !(aChar >= 'A' && aChar <= 'F'))

        {

            return false;

        }

        return true;

    }

    private static void validateUnescapedUrl(String aUrl)

    {

        boolean isUnescaped = false;

        char charip1 = 0;

        char charip2 = 0;

        try

        {

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

            {

                if (aUrl.charAt(i) == '%')

                {

                    isUnescaped = true;

                    charip1 = aUrl.charAt(i + 1);

                    charip2 = aUrl.charAt(i + 2);

                    if ((!isValidHexDigit(charip1) || !isValidHexDigit(charip2)))

                    {

                        throw new IllegalArgumentException();

                    }

                }

                else

                {

                    if ((aUrl.charAt(i) > 127) && isUnescaped)

                    {

                        throw new IllegalArgumentException();

                    }

                }

            }

        }

        catch (StringIndexOutOfBoundsException ex)

        {

            // Occurs in case % is not followed by 2 characters.

            throw new IllegalArgumentException();

        }

    }

    /*

     * Created: 17 April 1997 Author: Bert Bos <bert@w3.org>

     *

     * unescape: http://www.w3.org/International/unescape.java

     *

     * Copyright © 1997 World Wide Web Consortium, (Massachusetts Institute of

     * Technology, European Research Consortium for Informatics and Mathematics,

     * Keio University). All Rights Reserved. This work is distributed under the

     * W3C® Software License [1] 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.

     *

     * [1] http://www.w3.org/Consortium/Legal/2002/copyright-software-20021231

     */

    public static String unescape(String s)

    {

        StringBuffer sbuf = new StringBuffer("");

        int l = s.length();

        int ch = -1;

        int b, sumb = 0;

        for (int i = 0, more = -1; i < l; i++)

        {

            /* Get next byte b from URL segment s */

            switch (ch = s.charAt(i))

            {

            case '%':

                ch = s.charAt(++i);

                int hb = (Character.isDigit((char) ch) ? ch - '0'

                          : 10 + Character.toLowerCase((char) ch) - 'a') & 0xF;

                ch = s.charAt(++i);

                int lb = (Character.isDigit((char) ch) ? ch - '0'

                          : 10 + Character.toLowerCase((char) ch) - 'a') & 0xF;

                b = (hb << 4) | lb;

                break;

            case '+':

                b = ' ';

                break;

            default:

                b = ch;

            }

            /* Decode byte b as UTF-8, sumb collects incomplete chars */

            if ((b & 0xc0) == 0x80)

            { // 10xxxxxx (continuation byte)

                sumb = (sumb << 6) | (b & 0x3f); // Add 6 bits to sumb

                if (--more == 0)

                    sbuf.append((char) sumb); // Add char to sbuf

            }

            else if ((b & 0x80) == 0x00)

            { // 0xxxxxxx (yields 7 bits)

                sbuf.append((char) b); // Store in sbuf

            }

            else if ((b & 0xe0) == 0xc0)

            { // 110xxxxx (yields 5 bits)

                sumb = b & 0x1f;

                more = 1; // Expect 1 more byte

            }

            else if ((b & 0xf0) == 0xe0)

            { // 1110xxxx (yields 4 bits)

                sumb = b & 0x0f;

                more = 2; // Expect 2 more bytes

            }

            else if ((b & 0xf8) == 0xf0)

            { // 11110xxx (yields 3 bits)

                sumb = b & 0x07;

                more = 3; // Expect 3 more bytes

            }

            else if ((b & 0xfc) == 0xf8)

            { // 111110xx (yields 2 bits)

                sumb = b & 0x03;

                more = 4; // Expect 4 more bytes

            }

            else

                /* if ((b & 0xfe) == 0xfc) */  // 1111110x (yields 1 bit)

            {

                sumb = b & 0x01;

                more = 5; // Expect 5 more bytes

            }

            /* We don't test if the UTF-8 encoding is well-formed */

        }

        return sbuf.toString();

    }

}

/**

 * Provides a method to encode any string into a URL-safe form. Non-ASCII

 * characters are first encoded as sequences of two or three bytes, using the

 * UTF-8 algorithm, before being encoded as %HH escapes.

 *

 * Created: 17 April 1997 Author: Bert Bos <bert@w3.org>

 *

 * URLUTF8Encoder: http://www.w3.org/International/URLUTF8Encoder.java

 *

 * Copyright © 1997 World Wide Web Consortium, (Massachusetts Institute of

 * Technology, European Research Consortium for Informatics and Mathematics,

 * Keio University). All Rights Reserved. This work is distributed under the

 * W3C® Software License [1] 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.

 *

 * [1] http://www.w3.org/Consortium/Legal/2002/copyright-software-20021231

 */

class URLUTF8Encoder

{

    final static String[] hex = { "%00", "%01", "%02", "%03", "%04", "%05",

                                  "%06", "%07", "%08", "%09", "%0a", "%0b", "%0c", "%0d", "%0e",

                                  "%0f", "%10", "%11", "%12", "%13", "%14", "%15", "%16", "%17",

                                  "%18", "%19", "%1a", "%1b", "%1c", "%1d", "%1e", "%1f", "%20",

                                  "%21", "%22", "%23", "%24", "%25", "%26", "%27", "%28", "%29",

                                  "%2a", "%2b", "%2c", "%2d", "%2e", "%2f", "%30", "%31", "%32",

                                  "%33", "%34", "%35", "%36", "%37", "%38", "%39", "%3a", "%3b",

                                  "%3c", "%3d", "%3e", "%3f", "%40", "%41", "%42", "%43", "%44",

                                  "%45", "%46", "%47", "%48", "%49", "%4a", "%4b", "%4c", "%4d",

                                  "%4e", "%4f", "%50", "%51", "%52", "%53", "%54", "%55", "%56",

                                  "%57", "%58", "%59", "%5a", "%5b", "%5c", "%5d", "%5e", "%5f",

                                  "%60", "%61", "%62", "%63", "%64", "%65", "%66", "%67", "%68",

                                  "%69", "%6a", "%6b", "%6c", "%6d", "%6e", "%6f", "%70", "%71",

                                  "%72", "%73", "%74", "%75", "%76", "%77", "%78", "%79", "%7a",

                                  "%7b", "%7c", "%7d", "%7e", "%7f", "%80", "%81", "%82", "%83",

                                  "%84", "%85", "%86", "%87", "%88", "%89", "%8a", "%8b", "%8c",

                                  "%8d", "%8e", "%8f", "%90", "%91", "%92", "%93", "%94", "%95",

                                  "%96", "%97", "%98", "%99", "%9a", "%9b", "%9c", "%9d", "%9e",

                                  "%9f", "%a0", "%a1", "%a2", "%a3", "%a4", "%a5", "%a6", "%a7",

                                  "%a8", "%a9", "%aa", "%ab", "%ac", "%ad", "%ae", "%af", "%b0",

                                  "%b1", "%b2", "%b3", "%b4", "%b5", "%b6", "%b7", "%b8", "%b9",

                                  "%ba", "%bb", "%bc", "%bd", "%be", "%bf", "%c0", "%c1", "%c2",

                                  "%c3", "%c4", "%c5", "%c6", "%c7", "%c8", "%c9", "%ca", "%cb",

                                  "%cc", "%cd", "%ce", "%cf", "%d0", "%d1", "%d2", "%d3", "%d4",

                                  "%d5", "%d6", "%d7", "%d8", "%d9", "%da", "%db", "%dc", "%dd",

                                  "%de", "%df", "%e0", "%e1", "%e2", "%e3", "%e4", "%e5", "%e6",

                                  "%e7", "%e8", "%e9", "%ea", "%eb", "%ec", "%ed", "%ee", "%ef",

                                  "%f0", "%f1", "%f2", "%f3", "%f4", "%f5", "%f6", "%f7", "%f8",

                                  "%f9", "%fa", "%fb", "%fc", "%fd", "%fe", "%ff"

                                };

    /**

     * Encode a string to the "x-www-form-urlencoded" form, enhanced with the

     * UTF-8-in-URL proposal. This is what happens:

     *

     * <ul>

     * <li>

     * <p>

     * The ASCII characters 'a' through 'z', 'A' through 'Z', and '0' through

     * '9' remain the same.

     *

     * <li>

     * <p>

     * The unreserved characters - _ . ! ~ * ' ( ) remain the same.

     *

     * <li>

     * <p>

     * The space character ' ' is converted into a plus sign '+'.

     *

     * <li>

     * <p>

     * All other ASCII characters are converted into the 3-character string

     * "%xy", where xy is the two-digit hexadecimal representation of the

     * character code

     *

     * <li>

     * <p>

     * All non-ASCII characters are encoded in two steps: first to a sequence of

     * 2 or 3 bytes, using the UTF-8 algorithm; secondly each of these bytes is

     * encoded as "%xx".

     * </ul>

     *

     * @param s

     *            The string to be encoded

     * @return The encoded string

     */

    public static String encode(String s)

    {

        StringBuffer sbuf = new StringBuffer();

        int len = s.length();

        for (int i = 0; i < len; i++)

        {

            int ch = s.charAt(i);

            if ('A' <= ch && ch <= 'Z')

            { // 'A'..'Z'

                sbuf.append((char) ch);

            }

            else if ('a' <= ch && ch <= 'z')

            { // 'a'..'z'

                sbuf.append((char) ch);

            }

            else if ('0' <= ch && ch <= '9')

            { // '0'..'9'

                sbuf.append((char) ch);

            }

            else if (ch == ' ')

            { // space

                // sbuf.append('+');

                sbuf.append("%20");

            }

            else if (ch == '-'

                     || ch == '_' // unreserved

                     || ch == '.' || ch == '!' || ch == '~' || ch == '*'

                     || ch == '\'' || ch == '(' || ch == ')' || ch == ':'

                     || ch == '/')

            {

                sbuf.append((char) ch);

            }

            else if (ch <= 0x007f)

            { // other ASCII

                sbuf.append(hex[ch]);

            }

            else if (ch <= 0x07FF)

            { // non-ASCII <= 0x7FF

                sbuf.append(hex[0xc0 | (ch >> 6)]);

                sbuf.append(hex[0x80 | (ch & 0x3F)]);

            }

            else

            { // 0x7FF < ch <= 0xFFFF

                sbuf.append(hex[0xe0 | (ch >> 12)]);

                sbuf.append(hex[0x80 | ((ch >> 6) & 0x3F)]);

                sbuf.append(hex[0x80 | (ch & 0x3F)]);

            }

        }

        return sbuf.toString();

    }

}