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- ;(function () {
- var object = typeof exports != 'undefined' ? exports : this; // #8: web workers
- var chars = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=';
- function InvalidCharacterError(message) {
- this.message = message;
- }
- InvalidCharacterError.prototype = new Error;
- InvalidCharacterError.prototype.name = 'InvalidCharacterError';
- // encoder
- // [https://gist.github.com/999166] by [https://github.com/nignag]
- object.btoa || (
- object.btoa = function (input) {
- var str = String(input);
- for (
- // initialize result and counter
- var block, charCode, idx = 0, map = chars, output = '';
- // if the next str index does not exist:
- // change the mapping table to "="
- // check if d has no fractional digits
- str.charAt(idx | 0) || (map = '=', idx % 1);
- // "8 - idx % 1 * 8" generates the sequence 2, 4, 6, 8
- output += map.charAt(63 & block >> 8 - idx % 1 * 8)
- ) {
- charCode = str.charCodeAt(idx += 3/4);
- if (charCode > 0xFF) {
- throw new InvalidCharacterError("'btoa' failed: The string to be encoded contains characters outside of the Latin1 range.");
- }
- block = block << 8 | charCode;
- }
- return output;
- });
- // decoder
- // [https://gist.github.com/1020396] by [https://github.com/atk]
- object.atob || (
- object.atob = function (input) {
- var str = String(input).replace(/=+$/, '');
- if (str.length % 4 == 1) {
- throw new InvalidCharacterError("'atob' failed: The string to be decoded is not correctly encoded.");
- }
- for (
- // initialize result and counters
- var bc = 0, bs, buffer, idx = 0, output = '';
- // get next character
- buffer = str.charAt(idx++);
- // character found in table? initialize bit storage and add its ascii value;
- ~buffer && (bs = bc % 4 ? bs * 64 + buffer : buffer,
- // and if not first of each 4 characters,
- // convert the first 8 bits to one ascii character
- bc++ % 4) ? output += String.fromCharCode(255 & bs >> (-2 * bc & 6)) : 0
- ) {
- // try to find character in table (0-63, not found => -1)
- buffer = chars.indexOf(buffer);
- }
- return output;
- });
- }());
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