106 lines
3.5 KiB
JavaScript
106 lines
3.5 KiB
JavaScript
// Base64 JavaScript decoder
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// Copyright (c) 2008-2020 Lapo Luchini <lapo@lapo.it>
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// Permission to use, copy, modify, and/or distribute this software for any
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// purpose with or without fee is hereby granted, provided that the above
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// copyright notice and this permission notice appear in all copies.
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//
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// THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
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// WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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// MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
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// ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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// WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
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// ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
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// OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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(typeof define != 'undefined' ? define : function (factory) { 'use strict';
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if (typeof module == 'object') module.exports = factory();
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else window.base64 = factory();
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})(function () {
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"use strict";
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var Base64 = {},
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decoder, // populated on first usage
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haveU8 = (typeof Uint8Array == 'function');
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Base64.decode = function (a) {
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var isString = (typeof a == 'string');
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var i;
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if (decoder === undefined) {
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var b64 = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/",
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ignore = "= \f\n\r\t\u00A0\u2028\u2029";
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decoder = [];
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for (i = 0; i < 64; ++i)
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decoder[b64.charCodeAt(i)] = i;
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for (i = 0; i < ignore.length; ++i)
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decoder[ignore.charCodeAt(i)] = -1;
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// RFC 3548 URL & file safe encoding
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decoder['-'.charCodeAt(0)] = decoder['+'.charCodeAt(0)];
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decoder['_'.charCodeAt(0)] = decoder['/'.charCodeAt(0)];
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}
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var out = haveU8 ? new Uint8Array(a.length * 3 >> 2) : [];
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var bits = 0, char_count = 0, len = 0;
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for (i = 0; i < a.length; ++i) {
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var c = isString ? a.charCodeAt(i) : a[i];
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if (c == 61) // '='.charCodeAt(0)
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break;
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c = decoder[c];
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if (c == -1)
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continue;
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if (c === undefined)
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throw 'Illegal character at offset ' + i;
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bits |= c;
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if (++char_count >= 4) {
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out[len++] = (bits >> 16);
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out[len++] = (bits >> 8) & 0xFF;
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out[len++] = bits & 0xFF;
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bits = 0;
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char_count = 0;
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} else {
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bits <<= 6;
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}
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}
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switch (char_count) {
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case 1:
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throw "Base64 encoding incomplete: at least 2 bits missing";
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case 2:
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out[len++] = (bits >> 10);
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break;
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case 3:
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out[len++] = (bits >> 16);
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out[len++] = (bits >> 8) & 0xFF;
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break;
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}
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if (haveU8 && out.length > len) // in case it was originally longer because of ignored characters
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out = out.subarray(0, len);
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return out;
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};
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Base64.pretty = function (str) {
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// fix padding
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if (str.length % 4 > 0)
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str = (str + '===').slice(0, str.length + str.length % 4);
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// convert RFC 3548 to standard Base64
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str = str.replace(/-/g, '+').replace(/_/g, '/');
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// 80 column width
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return str.replace(/(.{80})/g, '$1\n');
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};
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Base64.re = /-----BEGIN [^-]+-----([A-Za-z0-9+/=\s]+)-----END [^-]+-----|begin-base64[^\n]+\n([A-Za-z0-9+/=\s]+)====/;
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Base64.unarmor = function (a) {
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var m = Base64.re.exec(a);
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if (m) {
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if (m[1])
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a = m[1];
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else if (m[2])
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a = m[2];
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else
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throw "RegExp out of sync";
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}
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return Base64.decode(a);
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};
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return Base64;
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});
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