eccd4a816a
From https://github.com/dankogai/js-base64 (cherry picked from commit 7e5c36ed5b7fc67ba919973834e015ce92b5708b)
140 lines
4.3 KiB
JavaScript
140 lines
4.3 KiB
JavaScript
/*
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* $Id: base64.js,v 2.6 2012/08/24 05:23:18 dankogai Exp dankogai $
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*
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* Licensed under the MIT license.
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* http://www.opensource.org/licenses/mit-license.php
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*
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* References:
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* http://en.wikipedia.org/wiki/Base64
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*/
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(function(global) {
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'use strict';
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// if node.js, we use Buffer
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var buffer;
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if (typeof module !== 'undefined' && module.exports) {
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buffer = require('buffer').Buffer;
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}
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// constants
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var b64chars
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= 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/';
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var b64tab = function(bin) {
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var t = {};
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for (var i = 0, l = bin.length; i < l; i++) t[bin.charAt(i)] = i;
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return t;
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}(b64chars);
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var fromCharCode = String.fromCharCode;
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// encoder stuff
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var cb_utob = function(c) {
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var cc = c.charCodeAt(0);
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return cc < 0x80 ? c
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: cc < 0x800 ? fromCharCode(0xc0 | (cc >>> 6))
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+ fromCharCode(0x80 | (cc & 0x3f))
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: fromCharCode(0xe0 | ((cc >>> 12) & 0x0f))
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+ fromCharCode(0x80 | ((cc >>> 6) & 0x3f))
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+ fromCharCode(0x80 | ( cc & 0x3f));
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};
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var utob = function(u) {
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return u.replace(/[^\x00-\x7F]/g, cb_utob);
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};
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var cb_encode = function(ccc) {
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var padlen = [0, 2, 1][ccc.length % 3],
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ord = ccc.charCodeAt(0) << 16
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| ((ccc.length > 1 ? ccc.charCodeAt(1) : 0) << 8)
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| ((ccc.length > 2 ? ccc.charCodeAt(2) : 0)),
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chars = [
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b64chars.charAt( ord >>> 18),
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b64chars.charAt((ord >>> 12) & 63),
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padlen >= 2 ? '=' : b64chars.charAt((ord >>> 6) & 63),
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padlen >= 1 ? '=' : b64chars.charAt(ord & 63)
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];
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return chars.join('');
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};
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var btoa = global.btoa || function(b) {
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return b.replace(/[\s\S]{1,3}/g, cb_encode);
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};
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var _encode = buffer
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? function (u) { return (new buffer(u)).toString('base64') }
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: function (u) { return btoa(utob(u)) }
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;
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var encode = function(u, urisafe) {
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return !urisafe
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? _encode(u)
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: _encode(u).replace(/[+\/]/g, function(m0) {
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return m0 == '+' ? '-' : '_';
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});
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};
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var encodeURI = function(u) { return encode(u, true) };
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// decoder stuff
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var re_btou = /[\xC0-\xDF][\x80-\xBF]|[\xE0-\xEF][\x80-\xBF]{2}/g;
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var cb_btou = function(ccc) {
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return fromCharCode(
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ccc.length < 3 ? ((0x1f & ccc.charCodeAt(0)) << 6)
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| (0x3f & ccc.charCodeAt(1))
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: ((0x0f & ccc.charCodeAt(0)) << 12)
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| ((0x3f & ccc.charCodeAt(1)) << 6)
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| (0x3f & ccc.charCodeAt(2))
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);
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};
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var btou = function(b) {
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return b.replace(re_btou, cb_btou);
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};
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var cb_decode = function(cccc) {
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var len = cccc.length,
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padlen = len % 4,
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n = (len > 0 ? b64tab[cccc.charAt(0)] << 18 : 0)
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| (len > 1 ? b64tab[cccc.charAt(1)] << 12 : 0)
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| (len > 2 ? b64tab[cccc.charAt(2)] << 6 : 0)
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| (len > 3 ? b64tab[cccc.charAt(3)] : 0),
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chars = [
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fromCharCode( n >>> 16),
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fromCharCode((n >>> 8) & 0xff),
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fromCharCode( n & 0xff)
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];
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chars.length -= [0, 0, 2, 1][padlen];
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return chars.join('');
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};
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var atob = global.atob || function(a){
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return a.replace(/[\s\S]{1,4}/g, cb_decode);
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};
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var _decode = buffer
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? function(a) { return (new buffer(a, 'base64')).toString() }
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: function(a) { return btou(atob(a)) }
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;
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var decode = function(a){
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return _decode(
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a.replace(/[-_]/g, function(m0) { return m0 == '-' ? '+' : '/' })
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.replace(/[^A-Za-z0-9\+\/]/g, '')
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);
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};
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// export Base64
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global.Base64 = {
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atob: atob,
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btoa: btoa,
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fromBase64: decode,
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toBase64: encode,
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utob: utob,
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encode: encode,
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encodeURI: encodeURI,
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btou: btou,
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decode: decode
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};
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// if ES5 is available, make Base64.extendString() available
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if (typeof Object.defineProperty === 'function') {
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var noEnum = function(v){
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return {value:v,enumerable:false,writable:true,configurable:true};
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};
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global.Base64.extendString = function () {
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Object.defineProperty(
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String.prototype, 'fromBase64', noEnum(function () {
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return decode(this)
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}));
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Object.defineProperty(
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String.prototype, 'toBase64', noEnum(function (urisafe) {
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return encode(this, urisafe)
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}));
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};
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}
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// that's it!
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})(this);
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