58 lines
1.5 KiB
JavaScript
58 lines
1.5 KiB
JavaScript
/** @fileOverview Bit array codec implementations.
|
|
*
|
|
* @author Emily Stark
|
|
* @author Mike Hamburg
|
|
* @author Dan Boneh
|
|
*/
|
|
|
|
/** @namespace Base64 encoding/decoding */
|
|
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;
|
|
}
|
|
};
|