var base64EncodeChars = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
var base64DecodeChars = new Array(
    -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
    -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
    -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 62, -1, -1, -1, 63,
    52, 53, 54, 55, 56, 57, 58, 59, 60, 61, -1, -1, -1, -1, -1, -1,
    -1, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14,
    15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, -1, -1, -1, -1, -1,
    -1, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40,
    41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, -1, -1, -1, -1, -1);

function base64decode(str) {
    var c1, c2, c3, c4;
    var i, len, out;

    len = str.length;
    i = 0;
    out = "";
    while(i < len) {
    /* c1 */
    do {
        c1 = base64DecodeChars[str.charCodeAt(i++) & 0xff];
    } while(i < len && c1 == -1);
    if(c1 == -1)
        break;

    /* c2 */
    do {
        c2 = base64DecodeChars[str.charCodeAt(i++) & 0xff];
    } while(i < len && c2 == -1);
    if(c2 == -1)
        break;

    out += String.fromCharCode((c1 << 2) | ((c2 & 0x30) >> 4));

    /* c3 */
    do {
        c3 = str.charCodeAt(i++) & 0xff;
        if(c3 == 61)
        return out;
        c3 = base64DecodeChars[c3];
    } while(i < len && c3 == -1);
    if(c3 == -1)
        break;

    out += String.fromCharCode(((c2 & 0XF) << 4) | ((c3 & 0x3C) >> 2));

    /* c4 */
    do {
        c4 = str.charCodeAt(i++) & 0xff;
        if(c4 == 61)
        return out;
        c4 = base64DecodeChars[c4];
    } while(i < len && c4 == -1);
    if(c4 == -1)
        break;
    out += String.fromCharCode(((c3 & 0x03) << 6) | c4);
    }
    return out;
}

function utf8to16(str) {
    var out, i, len, c;
    var char2, char3;

    out = "";
    len = str.length;
    i = 0;
    while(i < len) {
    c = str.charCodeAt(i++);
    switch(c >> 4)
    { 
      case 0: case 1: case 2: case 3: case 4: case 5: case 6: case 7:
        // 0xxxxxxx
        out += str.charAt(i-1);
        break;
      case 12: case 13:
        // 110x xxxx   10xx xxxx
        char2 = str.charCodeAt(i++);
        out += String.fromCharCode(((c & 0x1F) << 6) | (char2 & 0x3F));
        break;
      case 14:
        // 1110 xxxx 10xx xxxx 10xx xxxx
        char2 = str.charCodeAt(i++);
        char3 = str.charCodeAt(i++);
        out += String.fromCharCode(((c & 0x0F) << 12) |
                       ((char2 & 0x3F) << 6) |
                       ((char3 & 0x3F) << 0));
        break;
    }
    }

    return out;
}