package anzsoft.xmpp4gwt.client;

/**
 * Simple class for Base64 encoding and decoding. Original javascript code was
 * found at http://www.webtoolkit.info/javascript-base64.html .
 * 
 */
public class Base64 {
	@SuppressWarnings("unused")
	private static final String _keyStr = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=";

	@SuppressWarnings("unused")
	private static native String _utf8_decode(String utftext) /*-{
																var string = "";
																var i = 0;
																var c = c1 = c2 = 0;

																while ( i < utftext.length ) {
																c = utftext.charCodeAt(i);

																if (c < 128) {
																string += String.fromCharCode(c);
																i++;
																}
																else if((c > 191) && (c < 224)) {
																c2 = utftext.charCodeAt(i+1);
																string += String.fromCharCode(((c & 31) << 6) | (c2 & 63));
																i += 2;
																}
																else {
																c2 = utftext.charCodeAt(i+1);
																c3 = utftext.charCodeAt(i+2);
																string += String.fromCharCode(((c & 15) << 12) | ((c2 & 63) << 6) | (c3 & 63));
																i += 3;
																}

																}

																return string;
																}-*/;

	@SuppressWarnings("unused")
	private static native String _utf8_encode(String string) /*-{		
																string = string.replace(/\r\n/g,"\n");
																var utftext = "";

																for (var n = 0; n < string.length; n++) {

																var c = string.charCodeAt(n);

																if (c < 128) {
																utftext += String.fromCharCode(c);
																}
																else if((c > 127) && (c < 2048)) {
																utftext += String.fromCharCode((c >> 6) | 192);
																utftext += String.fromCharCode((c & 63) | 128);
																}
																else {
																utftext += String.fromCharCode((c >> 12) | 224);
																utftext += String.fromCharCode(((c >> 6) & 63) | 128);
																utftext += String.fromCharCode((c & 63) | 128);
																}
																}
																
																return utftext;
																}-*/;

	// public method for decoding
	public static native String decode(String input) /*-{
														var output = "";
														var chr1, chr2, chr3;
														var enc1, enc2, enc3, enc4;
														var i = 0;

														input = input.replace(/[^A-Za-z0-9\+\/\=]/g, "");

														while (i < input.length) {

														enc1 = @anzsoft.xmpp4gwt.client.Base64::_keyStr.indexOf(input.charAt(i++));
														enc2 = @anzsoft.xmpp4gwt.client.Base64::_keyStr.indexOf(input.charAt(i++));
														enc3 = @anzsoft.xmpp4gwt.client.Base64::_keyStr.indexOf(input.charAt(i++));
														enc4 = @anzsoft.xmpp4gwt.client.Base64::_keyStr.indexOf(input.charAt(i++));

														chr1 = (enc1 << 2) | (enc2 >> 4);
														chr2 = ((enc2 & 15) << 4) | (enc3 >> 2);
														chr3 = ((enc3 & 3) << 6) | enc4;

														output = output + String.fromCharCode(chr1);

														if (enc3 != 64) {
														output = output + String.fromCharCode(chr2);
														}
														if (enc4 != 64) {
														output = output + String.fromCharCode(chr3);
														}

														}

														output = @anzsoft.xmpp4gwt.client.Base64::_utf8_decode(Ljava/lang/String;)(output);

														return output;
														}-*/;

	// private method for UTF-8 decoding

	// public method for encoding
	public static native String encode(String input) /*-{
														var output = "";
														var chr1, chr2, chr3, enc1, enc2, enc3, enc4;
														var i = 0;

														input = @anzsoft.xmpp4gwt.client.Base64::_utf8_encode(Ljava/lang/String;)(input);

														while (i < input.length) {
														chr1 = input.charCodeAt(i++);
														chr2 = input.charCodeAt(i++);
														chr3 = input.charCodeAt(i++);

														enc1 = chr1 >> 2;
														enc2 = ((chr1 & 3) << 4) | (chr2 >> 4);
														enc3 = ((chr2 & 15) << 2) | (chr3 >> 6);
														enc4 = chr3 & 63;

														if (isNaN(chr2)) {
														enc3 = enc4 = 64;
														} else if (isNaN(chr3)) {
														enc4 = 64;
														}

														output = output +
														@anzsoft.xmpp4gwt.client.Base64::_keyStr.charAt(enc1) + @anzsoft.xmpp4gwt.client.Base64::_keyStr.charAt(enc2) +
														@anzsoft.xmpp4gwt.client.Base64::_keyStr.charAt(enc3) + @anzsoft.xmpp4gwt.client.Base64::_keyStr.charAt(enc4);
														}

														return output;
														}-*/;
}