File: base64.js

/*******************************************
  Base64 encoding in javascript
  Autor: valyala (valyala@tut.by)
********************************************/
function base64_encode(a) {
    var chars = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/'.split('');
    var i, n = a.length, tmp = 0, s = Array();
    i = j = 0;
    while (i < n) {
        tmp = (tmp << 8) | a[i];
        if (i % 3 == 2) {
            s[s.length] = chars[(tmp >> 18) & 0x3f];
            s[s.length] = chars[(tmp >> 12) & 0x3f];
            s[s.length] = chars[(tmp >> 6) & 0x3f];
            s[s.length] = chars[tmp & 0x3f];
            j += 4;
            if (j % 76 == 0) s[s.length] = '\r\n';
            tmp = 0;
        }
        i++;
    }
    switch (i % 3) {
    case 1 :
        s[s.length] = chars[(tmp >> 2) & 0x3f];
        s[s.length] = chars[(tmp << 4) & 0x3f];
        s[s.length] = '=';
        s[s.length] = '=';
        break;
    case 2 :
        s[s.length] = chars[(tmp >> 10) & 0x3f];
        s[s.length] = chars[(tmp >> 4) & 0x3f];
        s[s.length] = chars[(tmp << 2) & 0x3f];
        s[s.length] = '=';
        break;
    }
    return s.join('');
}

function base64_decode(s) {
    s = s.split('');
    var chars = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/'.split('');
    var i, j, codes = Object(), a = Array(), n = s.length, tmp = 0;
    for (i = 0; i < 64; i++) codes[chars[i]] = i; // ôîðìèðóåì òàáëèöó êîäîâ
    i = j = 0;
    while (i < n) {
        while (i < n && isNaN(codes[s[i]]) && s[i] != '=') i++; // ïðîïóñêàåì íåâåðíûå ñèìâîëû
        if (i == n || s[i] == '=') break;
        tmp = (tmp << 6) | codes[s[i]];
        if (j % 4 == 3) {
            a[a.length] = (tmp >> 16) & 0xff;
            a[a.length] = (tmp >> 8) & 0xff;
            a[a.length] = tmp & 0xff;
            tmp = 0;
        }
        j++;
        i++;
    }
    switch (j % 4) {
    case 2 :
        a[a.length] = (tmp >> 4) & 0xff;
        break;
    case 3 :
        a[a.length] = (tmp >> 10) & 0xff;
        a[a.length] = (tmp >> 2) & 0xff;
        break;
    }
    return a;
}

function utf8_encode(s) {
    var n = s.length, i, a = Array(), ch;
    for (i = 0; i < n; i++) {
        ch = s.charCodeAt(i);
        if (!(ch >> 7)) a[a.length] = ch; // îäèí áàéò
        else if (!(ch >> 11)) {
            // äâà áàéòà
            a[a.length] = 0xc0 | (ch >> 6);
            a[a.length] = 0x80 | (ch & 0x3f);
        } else if (!(ch >> 16)) {
            // òðè áàéòà
            a[a.length] = 0xe0 | (ch >> 12);
            a[a.length] = 0x80 | ((ch >> 6) & 0x3f);
            a[a.length] = 0x80 | (ch & 0x3f);
        } else {
            // ÷åòûðå áàéòà
            a[a.length] = 0xf0 | (ch >> 18);
            a[a.length] = 0x80 | ((ch >> 12) & 0x3f);
            a[a.length] = 0x80 | ((ch >> 6) & 0x3f);
            a[a.length] = 0x80 | (ch & 0x3f);
        }
    }
    return a;
}

function utf8_decode(a) {
    var n = a.length, i, s = '', ch;
    i = 0;
    while (i < n) {
        if (!(a[i] & 0x80)) ch = a[i]; // îäèí áàéò
        else if (i + 1 < n && !((a[i + 1] & 0xc0) ^ 0x80)) {
            if (!((a[i] & 0xe0) ^ 0xc0)) {
                ch = ((a[i] & 0x1f) << 6) | (a[i + 1] & 0x3f); // äâà áàéòà
                i++;
            }
            else if (i + 2 < n && !((a[i + 2] & 0xc0) ^ 0x80)) {
                if (!((a[i] & 0xf0) ^ 0xe0)) {
                    ch = ((a[i] & 0x0f) << 12) | ((a[i + 1] & 0x3f) << 6) | (a[i + 2] & 0x3f); // òðè áàéòà
                    i += 2;
                }
                else if (i + 3 < n && !((a[i + 3] & 0xc0) ^ 0x80)) {
                    if (!((a[i] & 0xf8) ^ 0xf0)) {
                        ch = ((a[i] & 0x07) << 18) | ((a[i + 1] & 0x3f) << 12) | ((a[i + 2] & 0x3f) << 6) | (a[i + 3] & 0x3f); // ÷åòûðå áàéòà
                        i += 3;
                    }
                    else {
                        // íåâåðíûé ôîðìàò ñèìâîëà ñ èíäåêñîì i
                    }
                } else {
                    // íåâåðíûé ôîðìàò ñèìâîëà ñ èíäåêñîì i + 3
                }
            } else {
                // íåâåðíûé ôîðìàò ñèìâîëà ñ èíäåêñîì i + 2
            }
        } else {
            // íåâåðíûé ôîðìàò ñèìâîëà ñ èíäåêñîì i + 1
        }
        s += String.fromCharCode(ch);
        i++;
    }
    return s;
}

/********************************************************************************/

function b64dec(str)
{
	return utf8_decode(base64_decode(str));
}

function b64enc(str)
{
	return base64_encode(utf8_encode(str));
}