node-ssl-certificates/lib/parser/asn1/base64.js

a node.js library for fetching, parsing and validating ssl-certificates

// Base64 JavaScript decoder
// Copyright (c) 2008-2022 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.

(typeof define != "undefined" ? define : function(factory) {
  "use strict";
  if (typeof module == "object") module.exports = factory();
  else window.base64 = factory();
})(function() {
  "use strict";

  const Base64 = {};
  let decoder; // populated on first usage
  const haveU8 = (typeof Uint8Array == "function");

  Base64.decode = function(a) {
    const isString = (typeof a == "string");
    let i;
    if (decoder === undefined) {
      const b64 = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
      const 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;
      }
      // RFC 3548 URL & file safe encoding
      decoder["-".charCodeAt(0)] = decoder["+".charCodeAt(0)];
      decoder["_".charCodeAt(0)] = decoder["/".charCodeAt(0)];
    }
    let out = haveU8 ? new Uint8Array(a.length * 3 >> 2) : [];
    let bits = 0; let char_count = 0; let 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;
  };

  Base64.pretty = function(str) {
    // fix padding
    if (str.length % 4 > 0) {
      str = (str + "===").slice(0, str.length + str.length % 4);
    }
    // convert RFC 3548 to standard Base64
    str = str.replace(/-/g, "+").replace(/_/g, "/");
    // 80 column width
    return str.replace(/(.{80})/g, "$1\n");
  };

  Base64.re = /-----BEGIN [^-]+-----([A-Za-z0-9+/=\s]+)-----END [^-]+-----|begin-base64[^\n]+\n([A-Za-z0-9+/=\s]+)====|^([A-Za-z0-9+/=\s]+)$/;
  Base64.unarmor = function(a) {
    const 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);
  };

  return Base64;
});