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JavaScript generic ASN.1 parser (mirror)
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asn1js base64.js
3.8 kB · 104 lines
JavaScript
at github-101
123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105// Base64 JavaScript decoder// Copyright (c) 2008 Lapo Luchini <lapo@lapo.it>
// Permission to use, copy, modify, and/or distribute this software for any// purpose with or without fee is hereby granted, provided that the above// copyright notice and this permission notice appear in all copies.//// THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES// WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF// MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR// ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES// WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN// ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF// OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
const haveU8 = (typeof Uint8Array == 'function');
let decoder; // populated on first usage
export class Base64 {
static decode(a) { let isString = (typeof a == 'string'); let i; if (decoder === undefined) { let b64 = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/', ignore = '= \f\n\r\t\u00A0\u2028\u2029'; decoder = []; for (i = 0; i < 64; ++i) decoder[b64.charCodeAt(i)] = i; for (i = 0; i < ignore.length; ++i) decoder[ignore.charCodeAt(i)] = -1; // also support decoding Base64url (RFC 4648 section 5) decoder['-'.charCodeAt(0)] = decoder['+'.charCodeAt(0)]; decoder['_'.charCodeAt(0)] = decoder['/'.charCodeAt(0)]; } let out = haveU8 ? new Uint8Array(a.length * 3 >> 2) : []; let bits = 0, char_count = 0, len = 0; for (i = 0; i < a.length; ++i) { let c = isString ? a.charCodeAt(i) : a[i]; if (c == 61) // '='.charCodeAt(0) break; c = decoder[c]; if (c == -1) continue; if (c === undefined) throw 'Illegal character at offset ' + i; bits |= c; if (++char_count >= 4) { out[len++] = (bits >> 16); out[len++] = (bits >> 8) & 0xFF; out[len++] = bits & 0xFF; bits = 0; char_count = 0; } else { bits <<= 6; } } switch (char_count) { case 1: throw 'Base64 encoding incomplete: at least 2 bits missing'; case 2: out[len++] = (bits >> 10); break; case 3: out[len++] = (bits >> 16); out[len++] = (bits >> 8) & 0xFF; break; } if (haveU8 && out.length > len) // in case it was originally longer because of ignored characters out = out.subarray(0, len); return out; }
static pretty(str) { // fix padding let pad = 4 - str.length % 4; if (pad < 4) str += '==='.slice(0, pad); // convert Base64url (RFC 4648 section 5) to standard Base64 (RFC 4648 section 4) str = str.replace(/-/g, '+').replace(/_/g, '/'); // 80 column width return str.replace(/.{80}/g, '$&\n'); }
static unarmor(a) { let m = Base64.re.exec(a); if (m) { if (m[1]) a = m[1]; else if (m[2]) a = m[2]; else if (m[3]) a = m[3]; else throw 'RegExp out of sync'; } return Base64.decode(a); }
}
Base64.re = /-----BEGIN [^-]+-----([A-Za-z0-9+/=\s]+)-----END [^-]+-----|begin-base64[^\n]+\n([A-Za-z0-9+/=\s]+)====|^([A-Za-z0-9+/=\s]+)$/;