/** @fileOverview Bit array codec implementations.
*
* @author Emily Stark
* @author Mike Hamburg
* @author Dan Boneh
*/
/**
* Base64 encoding/decoding
* @namespace
*/
sjcl.codec.base64 = {
/** The base64 alphabet.
* @private
*/
_chars: "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/",
/** Convert from a bitArray to a base64 string. */
fromBits: function (arr, _noEquals, _url) {
var out = "", i, bits=0, c = sjcl.codec.base64._chars, ta=0, bl = sjcl.bitArray.bitLength(arr);
if (_url) {
c = c.substr(0,62) + '-_';
}
for (i=0; out.length * 6 < bl; ) {
out += c.charAt((ta ^ arr[i]>>>bits) >>> 26);
if (bits < 6) {
ta = arr[i] << (6-bits);
bits += 26;
i++;
} else {
ta <<= 6;
bits -= 6;
}
}
while ((out.length & 3) && !_noEquals) { out += "="; }
return out;
},
/** Convert from a base64 string to a bitArray */
toBits: function(str, _url) {
str = str.replace(/\s|=/g,'');
var out = [], i, bits=0, c = sjcl.codec.base64._chars, ta=0, x;
if (_url) {
c = c.substr(0,62) + '-_';
}
for (i=0; i<str.length; i++) {
x = c.indexOf(str.charAt(i));
if (x < 0) {
throw new sjcl.exception.invalid("this isn't base64!");
}
if (bits > 26) {
bits -= 26;
out.push(ta ^ x>>>bits);
ta = x << (32-bits);
} else {
bits += 6;
ta ^= x << (32-bits);
}
}
if (bits&56) {
out.push(sjcl.bitArray.partial(bits&56, ta, 1));
}
return out;
}
};
sjcl.codec.base64url = {
fromBits: function (arr) { return sjcl.codec.base64.fromBits(arr,1,1); },
toBits: function (str) { return sjcl.codec.base64.toBits(str,1); }
};