在Javascript 中的Base64加密，支持中文加密及emoji表情的unicode编码的base64加密
转载高人分享的Base64加密。
解决了楼主在使用webscoket做web了聊天接口时出现的emoji表情的unicode编码的base64加密错误问题。
(function(global) {
'use strict';// existing version for noConflict()
var _Base64 = global.Base64;
var version = "2.1.9";
// if node.js, we use Buffer
var buffer;
if (typeof module !== 'undefined' && module.exports) {
try {
buffer = require('buffer').Buffer;
} catch (err) {}
}
// constants
var b64chars
= 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/';
var b64tab = function(bin) {
var t = {};
for (var i = 0, l = bin.length; i < l; i++) t[bin.charAt(i)] = i;
return t;
}(b64chars);
var fromCharCode = String.fromCharCode;
// encoder stuff
var cb_utob = function(c) {
if (c.length < 2) {
var cc = c.charCodeAt(0);
return cc < 0x80 ? c
: cc < 0x800 ? (fromCharCode(0xc0 | (cc >>> 6))
+ fromCharCode(0x80 | (cc & 0x3f)))
: (fromCharCode(0xe0 | ((cc >>> 12) & 0x0f))
+ fromCharCode(0x80 | ((cc >>> 6) & 0x3f))
+ fromCharCode(0x80 | ( cc & 0x3f)));
} else {
var cc = 0x10000
+ (c.charCodeAt(0) - 0xD800) * 0x400
+ (c.charCodeAt(1) - 0xDC00);
return (fromCharCode(0xf0 | ((cc >>> 18) & 0x07))
+ fromCharCode(0x80 | ((cc >>> 12) & 0x3f))
+ fromCharCode(0x80 | ((cc >>> 6) & 0x3f))
+ fromCharCode(0x80 | ( cc & 0x3f)));
}
};
var re_utob = /[\uD800-\uDBFF][\uDC00-\uDFFFF]|[^\x00-\x7F]/g;
var utob = function(u) {
return u.replace(re_utob, cb_utob);
};
var cb_encode = function(ccc) {
var padlen = [0, 2, 1][ccc.length % 3],
ord = ccc.charCodeAt(0) << 16
| ((ccc.length > 1 ? ccc.charCodeAt(1) : 0) << 8)
| ((ccc.length > 2 ? ccc.charCodeAt(2) : 0)),
chars = [
b64chars.charAt( ord >>> 18),
b64chars.charAt((ord >>> 12) & 63),
padlen >= 2 ? '=' : b64chars.charAt((ord >>> 6) & 63),
padlen >= 1 ? '=' : b64chars.charAt(ord & 63)
];
return chars.join('');
};
var btoa = global.btoa ? function(b) {
return global.btoa(b);
} : function(b) {
return b.replace(/[\s\S]{1,3}/g, cb_encode);
};
var _encode = buffer ? function (u) {
return (u.constructor === buffer.constructor ? u : new buffer(u))
.toString('base64')
}
: function (u) { return btoa(utob(u)) }
;
var encode = function(u, urisafe) {
return !urisafe
? _encode(String(u))
: _encode(String(u)).replace(/[+\/]/g, function(m0) {
return m0 == '+' ? '-' : '_';
}).replace(/=/g, '');
};
var encodeURI = function(u) { return encode(u, true) };
// decoder stuff
var re_btou = new RegExp([
'[\xC0-\xDF][\x80-\xBF]',
'[\xE0-\xEF][\x80-\xBF]{2}',
'[\xF0-\xF7][\x80-\xBF]{3}'
].join('|'), 'g');
var cb_btou = function(cccc) {
switch(cccc.length) {
case 4:
var cp = ((0x07 & cccc.charCodeAt(0)) << 18)
| ((0x3f & cccc.charCodeAt(1)) << 12)
| ((0x3f & cccc.charCodeAt(2)) << 6)
| (0x3f & cccc.charCodeAt(3)),
offset = cp - 0x10000;
return (fromCharCode((offset >>> 10) + 0xD800)
+ fromCharCode((offset & 0x3FF) + 0xDC00));
case 3:
return fromCharCode(
((0x0f & cccc.charCodeAt(0)) << 12)
| ((0x3f & cccc.charCodeAt(1)) << 6)
| (0x3f & cccc.charCodeAt(2))
);
default:
return fromCharCode(
((0x1f & cccc.charCodeAt(0)) << 6)
| (0x3f & cccc.charCodeAt(1))
);
}
};
var btou = function(b) {
return b.replace(re_btou, cb_btou);
};
var cb_decode = function(cccc) {
var len = cccc.length,
padlen = len % 4,
n = (len > 0 ? b64tab[cccc.charAt(0)] << 18 : 0)
| (len > 1 ? b64tab[cccc.charAt(1)] << 12 : 0)
| (len > 2 ? b64tab[cccc.charAt(2)] << 6 : 0)
| (len > 3 ? b64tab[cccc.charAt(3)] : 0),
chars = [
fromCharCode( n >>> 16),
fromCharCode((n >>> 8) & 0xff),
fromCharCode( n & 0xff)
];
chars.length -= [0, 0, 2, 1][padlen];
return chars.join('');
};
var atob = global.atob ? function(a) {
return global.atob(a);
} : function(a){
return a.replace(/[\s\S]{1,4}/g, cb_decode);
};
var _decode = buffer ? function(a) {
return (a.constructor === buffer.constructor
? a : new buffer(a, 'base64')).toString();
}
: function(a) { return btou(atob(a)) };
var decode = function(a){
return _decode(
String(a).replace(/[-_]/g, function(m0) { return m0 == '-' ? '+' : '/' })
.replace(/[^A-Za-z0-9\+\/]/g, '')
);
};
var noConflict = function() {
var Base64 = global.Base64;
global.Base64 = _Base64;
return Base64;
};
// export Base64
global.Base64 = {
VERSION: version,
atob: atob,
btoa: btoa,
fromBase64: decode,
toBase64: encode,
utob: utob,
encode: encode,
encodeURI: encodeURI,
btou: btou,
decode: decode,
noConflict: noConflict
};
// if ES5 is available, make Base64.extendString() available
if (typeof Object.defineProperty === 'function') {
var noEnum = function(v){
return {value:v,enumerable:false,writable:true,configurable:true};
};
global.Base64.extendString = function () {
Object.defineProperty(
String.prototype, 'fromBase64', noEnum(function () {
return decode(this)
}));
Object.defineProperty(
String.prototype, 'toBase64', noEnum(function (urisafe) {
return encode(this, urisafe)
}));
Object.defineProperty(
String.prototype, 'toBase64URI', noEnum(function () {
return encode(this, true)
}));
};
}
// that's it!
if (global['Meteor']) {
Base64 = global.Base64; // for normal export in Meteor.js
}
})(this);