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Base64.js
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Base64.js
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/*
* Base64 Encoding
*
* @author lellansin <lellansin@gmail.com>
* @website http://www.lellansin.com/tutorials/ciphers
*/
(function() {
var Base64 = {};
var ALPHABET = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=';
/*
* 编码
*/
Base64.encode = function (words) {
var cipher = '', code = utf8_encode(words);
var i = 0, chr1, chr2, chr3,
enc1, enc2, enc3, enc4;
while (i < code.length) {
chr1 = code.charCodeAt(i++);
chr2 = code.charCodeAt(i++);
chr3 = code.charCodeAt(i++);
enc1 = chr1 >> 2;
enc2 = ((chr1 & 3) << 4) | (chr2 >> 4);
enc3 = ((chr2 & 15) << 2) | (chr3 >> 6);
enc4 = chr3 & 63;
if (isNaN(chr2))
enc3 = enc4 = 64;
else if (isNaN(chr3))
enc4 = 64;
cipher += ALPHABET.charAt(enc1) + ALPHABET.charAt(enc2) +
ALPHABET.charAt(enc3) + ALPHABET.charAt(enc4);
}
return cipher;
};
/*
* 解码
*/
Base64.decode = function (text) {
var code = '', cipher = text.replace(/[^A-Za-z0-9\+\/\=]/g, '');
var i = 0, chr1, chr2, chr3,
enc1, enc2, enc3, enc4;
while (i < cipher.length) {
enc1 = ALPHABET.indexOf(cipher.charAt(i++));
enc2 = ALPHABET.indexOf(cipher.charAt(i++));
enc3 = ALPHABET.indexOf(cipher.charAt(i++));
enc4 = ALPHABET.indexOf(cipher.charAt(i++));
chr1 = (enc1 << 2) | (enc2 >> 4);
chr2 = ((enc2 & 15) << 4) | (enc3 >> 2);
chr3 = ((enc3 & 3) << 6) | enc4;
code += String.fromCharCode(chr1);
if (enc3 != 64)
code += String.fromCharCode(chr2);
if (enc4 != 64)
code += String.fromCharCode(chr3);
}
return utf8_decode(code);
};
var utf8_encode = function (string) {
return string.replace(/([^\r])|\r/g,
function(text, ch) {
if (!ch)
return '';
var c = ch.charCodeAt(0);
if (c < 128)
return ch;
else if((c > 127) && (c < 2048))
return String.fromCharCode((c >> 6) | 192) + String.fromCharCode((c & 63) | 128);
else
return String.fromCharCode((c >> 12) | 224) + String.fromCharCode(((c >> 6) & 63) | 128) + String.fromCharCode((c & 63) | 128);
});
};
var utf8_decode = function (utftext) {
var c1 = 0, c2 = 0, c3 = 0;
return utftext.replace(/([\x0-\x7F])|([\xC0-\xDF][.])|([.]{3})/,
function(text, asc, ansi, utf) {
if (asc)
return asc;
c1 = text.charCodeAt(0);
c2 = text.charCodeAt(1);
if(ansi)
return String.fromCharCode(((c1 & 31) << 6) | (c2 & 63));
c3 = utf.charCodeAt(2);
return String.fromCharCode(((c1 & 15) << 12) | ((c2 & 63) << 6) | (c3 & 63));
});
};
// -------------------------------------------------
// 明文
var text = 'hello world!';
// 编码
var str = Base64.encode(text);
console.log('密文', str);
// 解码
console.log('原文', Base64.decode(str));
})();