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base64.js
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base64.js
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/*
* Base 64 implementation in JavaScript
* Copyright (c) 2009 Nicholas C. Zakas. All rights reserved.
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
/**
* Base64-encodes a string of text.
* @param {String} text The text to encode.
* @return {String} The base64-encoded string.
*/
function base64Encode(text){
if (/([^\u0000-\u00ff])/.test(text)){
throw new Error("Can't base64 encode non-ASCII characters.");
}
var digits = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/",
i = 0,
cur, prev, byteNum,
result=[];
while(i < text.length){
cur = text.charCodeAt(i);
byteNum = i % 3;
switch(byteNum){
case 0: //first byte
result.push(digits.charAt(cur >> 2));
break;
case 1: //second byte
result.push(digits.charAt((prev & 3) << 4 | (cur >> 4)));
break;
case 2: //third byte
result.push(digits.charAt((prev & 0x0f) << 2 | (cur >> 6)));
result.push(digits.charAt(cur & 0x3f));
break;
}
prev = cur;
i++;
}
if (byteNum == 0){
result.push(digits.charAt((prev & 3) << 4));
result.push("==");
} else if (byteNum == 1){
result.push(digits.charAt((prev & 0x0f) << 2));
result.push("=");
}
return result.join("");
}
/**
* Base64-decodes a string of text.
* @param {String} text The text to decode.
* @return {String} The base64-decoded string.
*/
function base64Decode(text){
//ignore white space
text = text.replace(/\s/g,"");
//first check for any unexpected input
if(!(/^[a-z0-9\+\/\s]+\={0,2}$/i.test(text)) || text.length % 4 > 0){
throw new Error("Not a base64-encoded string.");
}
//local variables
var digits = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/",
cur, prev, digitNum,
i=0,
result = [];
//remove any equals signs
text = text.replace(/=/g, "");
//loop over each character
while(i < text.length){
cur = digits.indexOf(text.charAt(i));
digitNum = i % 4;
switch(digitNum){
//case 0: first digit - do nothing, not enough info to work with
case 1: //second digit
result.push(String.fromCharCode(prev << 2 | cur >> 4));
break;
case 2: //third digit
result.push(String.fromCharCode((prev & 0x0f) << 4 | cur >> 2));
break;
case 3: //fourth digit
result.push(String.fromCharCode((prev & 3) << 6 | cur));
break;
}
prev = cur;
i++;
}
//return a string
return result.join("");
}