Mega Code Archive
Provides a method to encode any string into a URL-safe form
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/**
*
* JFreeReport : a free Java reporting library
*
*
* Project Info: http://reporting.pentaho.org/
*
* (C) Copyright 2001-2007, by Object Refinery Ltd, Pentaho Corporation and Contributors.
*
* This library 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 library 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
* library; if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330,
* Boston, MA 02111-1307, USA.
*
* [Java is a trademark or registered trademark of Sun Microsystems, Inc.
* in the United States and other countries.]
*
* ------------
* UTFEncodingUtil.java
* ------------
* (C) Copyright 2001-2007, by Object Refinery Ltd, Pentaho Corporation and Contributors.
*/
import java.io.UnsupportedEncodingException;
/**
* 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.
* <p/>
* Code is the public example given at http://www.w3.org/International/O-URL-code.html
*
* @author Bert Bos
*/
public class UTFEncodingUtil
{
/**
* Private Constructor prevents Object Creation.
*/
private UTFEncodingUtil()
{
}
/**
* A lookup table.
*/
private static final 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 according to RFC 1738.
* <p/>
* <quote> "...Only alphanumerics [0-9a-zA-Z], the special characters "$-_.+!*'()," [not including the quotes - ed],
* and reserved characters used for their reserved purposes may be used unencoded within a URL."</quote>
* <p/>
* <ul> <li><p>The ASCII characters 'a' through 'z', 'A' through 'Z', and '0' through '9' remain the same.
* <p/>
* <li><p>The unreserved characters - _ . ! ~ * ' ( ) remain the same.
* <p/>
* <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
* <p/>
* <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 encodeUTF8(final String s)
{
final StringBuffer sbuf = new StringBuffer();
final char[] sChars = s.toCharArray();
final int len = sChars.length;
for (int i = 0; i < len; i++)
{
final int ch = sChars[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 == '-' || ch == '_' // unreserved
|| 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();
}
/**
* Encodes a byte-array. The array is expected to contain ASCII characters, or the result may not be valid.
*
* @param s the byte array
* @return the array as encoded string.
*/
private static String encodeBytes(final byte[] s)
{
final StringBuffer sbuf = new StringBuffer();
final int len = s.length;
for (int i = 0; i < len; i++)
{
final int ch = (s[i] & 0xff);
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 == '-' || ch == '_' // unreserved
|| ch == '.' || ch == '!'
|| ch == '~' || ch == '*'
|| ch == '\'' || ch == '('
|| ch == ')')
{
sbuf.append((char) ch);
}
else
{ // other ASCII
sbuf.append(hex[ch]);
}
}
return sbuf.toString();
}
/**
* Encodes thh given string using the provided encoding. The encoding must be a valid Java-encoding.
*
* @param s the string that should be encoded.
* @param encoding the encoding to tranform the string into bytes.
* @return the encoded string.
* @throws UnsupportedEncodingException if the specified encoding is not recognized.
*/
public static String encode(final String s, final String encoding)
throws UnsupportedEncodingException
{
if ("utf-8".equalsIgnoreCase(encoding))
{
return encodeUTF8(s);
}
return encodeBytes(s.getBytes(encoding));
}
/**
* Decodes the given string using the provided encoding. The encoding must be a valid
* Java-encoding.
*
* @param s the string that should be encoded.
* @param encoding the encoding to tranform the bytes into a string.
* @return the encoded string.
* @throws UnsupportedEncodingException if the specified encoding is not recognized.
*/
public static String decode(final String s, final String encoding)
throws UnsupportedEncodingException
{
if ("utf-8".equalsIgnoreCase(encoding))
{
return decodeUTF(s);
}
// the resulting string will never be greater than the encoded string
final byte[] result = new byte[s.length()];
final char[] chars = s.toCharArray();
int position = 0;
for (int i = 0; i < chars.length; i++)
{
final char ch = chars[i];
final int b;
switch (ch)
{
case'%':
final char lch = s.charAt(++i);
final int hb = (Character.isDigit(lch)
? lch - '0'
: 10 + Character.toLowerCase(lch) - 'a') & 0xF;
final char hch = s.charAt(++i);
final int lb = (Character.isDigit(hch)
? hch - '0'
: 10 + Character.toLowerCase(hch) - 'a') & 0xF;
b = (hb << 4) | lb;
break;
case'+':
b = ' ';
break;
default:
b = ch;
}
result[position] = (byte) b;
position += 1;
}
return new String(result, 0, position, encoding);
}
/**
* Decodes the given string using the encoding UTF-8.
*
* @param s the string that should be encoded.
* @return the encoded string.
*/
public static String decodeUTF(final String s)
{
final StringBuffer sbuf = new StringBuffer();
final char[] chars = s.toCharArray();
final int l = chars.length;
int sumb = 0;
for (int i = 0, more = -1; i < l; i++)
{
/* Get next byte b from URL segment s */
final int ch = chars[i];
final int b;
switch (ch)
{
case'%':
final char lch = s.charAt(++i);
final int hb = (Character.isDigit(lch)
? lch - '0'
: 10 + Character.toLowerCase(lch) - 'a') & 0xF;
final char hch = s.charAt(++i);
final int lb = (Character.isDigit(hch)
? hch - '0'
: 10 + Character.toLowerCase(hch) - '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();
}
}
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