/** public domain */
package org.xhtmlrenderer.simple.extend;
/**
* 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.
*
* @author Torbj�rn Gannholm
*/
public class URLUTF8Encoder {
/** Description of the Field */
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: <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>
*
* The space character ' ' is converted into a plus sign '+'. <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 encode( String s ) {
StringBuffer sbuf = new StringBuffer();
int len = s.length();
for ( int i = 0; i < len; i++ ) {
int ch = s.charAt( i );
append( sbuf, ch );
}
return sbuf.toString();
}
/**
* Description of the Method
*
* @param chars PARAM
* @return Returns
*/
public static String encode( char[] chars ) {
StringBuffer sbuf = new StringBuffer();
int len = chars.length;
for ( int i = 0; i < len; i++ ) {
int ch = chars[i];
append( sbuf, ch );
}
return sbuf.toString();
}
/**
* Description of the Method
*
* @param sbuf PARAM
* @param ch PARAM
*/
private static void append( StringBuffer sbuf, int ch ) {
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( '+' );
} 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 )] );
}
}
}