67 lines
2 KiB
JavaScript
67 lines
2 KiB
JavaScript
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// http://ntt.cc/2008/01/19/base64-encoder-decoder-with-javascript.html
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// window.atob and window.btoa
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(function (window) {
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var keyStr = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=";
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window.btoa || (window.btoa = function encode64(input) {
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input = escape(input);
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var output = "";
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var chr1, chr2, chr3 = "";
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var enc1, enc2, enc3, enc4 = "";
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var i = 0;
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do {
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chr1 = input.charCodeAt(i++);
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chr2 = input.charCodeAt(i++);
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chr3 = input.charCodeAt(i++);
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enc1 = chr1 >> 2;
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enc2 = ((chr1 & 3) << 4) | (chr2 >> 4);
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enc3 = ((chr2 & 15) << 2) | (chr3 >> 6);
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enc4 = chr3 & 63;
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if (isNaN(chr2)) {
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enc3 = enc4 = 64;
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} else if (isNaN(chr3)) {
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enc4 = 64;
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}
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output = output + keyStr.charAt(enc1) + keyStr.charAt(enc2) + keyStr.charAt(enc3) + keyStr.charAt(enc4);
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chr1 = chr2 = chr3 = "";
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enc1 = enc2 = enc3 = enc4 = "";
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} while (i < input.length);
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return output;
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});
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window.atob || (window.atob = function(input) {
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var output = "";
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var chr1, chr2, chr3 = "";
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var enc1, enc2, enc3, enc4 = "";
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var i = 0;
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// remove all characters that are not A-Z, a-z, 0-9, +, /, or =
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var base64test = /[^A-Za-z0-9\+\/\=]/g;
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if (base64test.exec(input)) {
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alert("There were invalid base64 characters in the input text.\n" + "Valid base64 characters are A-Z, a-z, 0-9, '+', '/',and '='\n" + "Expect errors in decoding.");
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}
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input = input.replace(/[^A-Za-z0-9\+\/\=]/g, "");
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do {
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enc1 = keyStr.indexOf(input.charAt(i++));
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enc2 = keyStr.indexOf(input.charAt(i++));
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enc3 = keyStr.indexOf(input.charAt(i++));
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enc4 = keyStr.indexOf(input.charAt(i++));
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chr1 = (enc1 << 2) | (enc2 >> 4);
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chr2 = ((enc2 & 15) << 4) | (enc3 >> 2);
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chr3 = ((enc3 & 3) << 6) | enc4;
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output = output + String.fromCharCode(chr1);
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if (enc3 != 64) {
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output = output + String.fromCharCode(chr2);
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}
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if (enc4 != 64) {
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output = output + String.fromCharCode(chr3);
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}
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chr1 = chr2 = chr3 = "";
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enc1 = enc2 = enc3 = enc4 = "";
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} while (i < input.length);
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return unescape(output);
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});
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}(this));
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