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mystic/source/_posts/oztex/viewdata/base64.js
2019-01-16 14:07:59 +11:00

115 lines
3.9 KiB
JavaScript

/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
// From: http://hg.mozilla.org/mozilla-central/raw-file/ec10630b1a54/js/src/devtools/jint/sunspider/string-base64.js
/*jslint white: false, bitwise: false, plusplus: false */
/*global console */
var Base64 = {
/* Convert data (an array of integers) to a Base64 string. */
toBase64Table : 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/'.split(''),
base64Pad : '=',
encode: function (data) {
"use strict";
var result = '';
var toBase64Table = Base64.toBase64Table;
var base64Pad = Base64.base64Pad;
var length = data.length;
var i;
// Convert every three bytes to 4 ascii characters.
/* BEGIN LOOP */
for (i = 0; i < (length - 2); i += 3) {
result += toBase64Table[data[i] >> 2];
result += toBase64Table[((data[i] & 0x03) << 4) + (data[i+1] >> 4)];
result += toBase64Table[((data[i+1] & 0x0f) << 2) + (data[i+2] >> 6)];
result += toBase64Table[data[i+2] & 0x3f];
}
/* END LOOP */
// Convert the remaining 1 or 2 bytes, pad out to 4 characters.
if (length%3) {
i = length - (length%3);
result += toBase64Table[data[i] >> 2];
if ((length%3) === 2) {
result += toBase64Table[((data[i] & 0x03) << 4) + (data[i+1] >> 4)];
result += toBase64Table[(data[i+1] & 0x0f) << 2];
result += base64Pad;
} else {
result += toBase64Table[(data[i] & 0x03) << 4];
result += base64Pad + base64Pad;
}
}
return result;
},
/* Convert Base64 data to a string */
toBinaryTable : [
-1,-1,-1,-1, -1,-1,-1,-1, -1,-1,-1,-1, -1,-1,-1,-1,
-1,-1,-1,-1, -1,-1,-1,-1, -1,-1,-1,-1, -1,-1,-1,-1,
-1,-1,-1,-1, -1,-1,-1,-1, -1,-1,-1,62, -1,-1,-1,63,
52,53,54,55, 56,57,58,59, 60,61,-1,-1, -1, 0,-1,-1,
-1, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9,10, 11,12,13,14,
15,16,17,18, 19,20,21,22, 23,24,25,-1, -1,-1,-1,-1,
-1,26,27,28, 29,30,31,32, 33,34,35,36, 37,38,39,40,
41,42,43,44, 45,46,47,48, 49,50,51,-1, -1,-1,-1,-1
],
decode: function (data, offset) {
"use strict";
offset = typeof(offset) !== 'undefined' ? offset : 0;
var toBinaryTable = Base64.toBinaryTable;
var base64Pad = Base64.base64Pad;
var result, result_length, idx, i, c, padding;
var leftbits = 0; // number of bits decoded, but yet to be appended
var leftdata = 0; // bits decoded, but yet to be appended
var data_length = data.indexOf('=') - offset;
if (data_length < 0) { data_length = data.length - offset; }
/* Every four characters is 3 resulting numbers */
result_length = (data_length >> 2) * 3 + Math.floor((data_length%4)/1.5);
result = new Array(result_length);
// Convert one by one.
/* BEGIN LOOP */
for (idx = 0, i = offset; i < data.length; i++) {
c = toBinaryTable[data.charCodeAt(i) & 0x7f];
padding = (data.charAt(i) === base64Pad);
// Skip illegal characters and whitespace
if (c === -1) {
console.error("Illegal character code " + data.charCodeAt(i) + " at position " + i);
continue;
}
// Collect data into leftdata, update bitcount
leftdata = (leftdata << 6) | c;
leftbits += 6;
// If we have 8 or more bits, append 8 bits to the result
if (leftbits >= 8) {
leftbits -= 8;
// Append if not padding.
if (!padding) {
result[idx++] = (leftdata >> leftbits) & 0xff;
}
leftdata &= (1 << leftbits) - 1;
}
}
/* END LOOP */
// If there are any bits left, the base64 string was corrupted
if (leftbits) {
throw {name: 'Base64-Error',
message: 'Corrupted base64 string'};
}
return result;
}
}; /* End of Base64 namespace */