bcrypt-b64.js

/* eslint-disable capitalized-comments,unicorn/number-literal-case,unicorn/no-abusive-eslint-disable */
'use strict';

/**
 * bcrypt's own non-standard base64 dictionary.
 **/
const BASE64_CODE = './ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789'.split(
  ''
);

/* eslint-disable prettier/prettier */
const BASE64_INDEX = [
  -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, -1, -1, -1,  0,  1, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, -1, -1,
  -1, -1, -1, -1, -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, 26, 27, -1, -1, -1, -1, -1, -1, 28, 29, 30,
  31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50,
  51, 52, 53, -1, -1, -1, -1, -1
];
/* eslint-enable prettier/prettier */

/**
 * Encodes a Buffer to base64 using the bcrypt's base64 dictionary.
 * @param {Buffer} buff Buffer to encode.
 * @returns {string} The buffer encoded as a string.
 */
function encode(buff) {
  const len = buff.byteLength;
  let off = 0;
  const stra = [];

  while (off < len) {
    let c1 = buff[off++] & 0xff;
    stra.push(BASE64_CODE[(c1 >> 2) & 0x3f]);
    c1 = (c1 & 0x03) << 4;
    if (off >= len) {
      stra.push(BASE64_CODE[c1 & 0x3f]);
      break;
    }
    let c2 = buff[off++] & 0xff;
    c1 |= (c2 >> 4) & 0x0f;
    stra.push(BASE64_CODE[c1 & 0x3f]);
    c1 = (c2 & 0x0f) << 2;
    if (off >= len) {
      stra.push(BASE64_CODE[c1 & 0x3f]);
      break;
    }
    c2 = buff[off++] & 0xff;
    c1 |= (c2 >> 6) & 0x03;
    stra.push(BASE64_CODE[c1 & 0x3f]);
    stra.push(BASE64_CODE[c2 & 0x3f]);
  }
  return stra.join('');
}

/**
 * Decodes a base64 encoded string using the bcrypt's base64 dictionary.
 * @param {string} str String to decode.
 * @returns {Buffer} The string decoded as a Buffer.
 * @inner
 */
function decode(str) {
  let off = 0;
  let olen = 0;
  const slen = str.length;
  const stra = [];
  const len = str.length;

  while (off < slen - 1 && olen < len) {
    let code = str.charCodeAt(off++);
    const c1 = code < BASE64_INDEX.length ? BASE64_INDEX[code] : -1;
    code = str.charCodeAt(off++);
    const c2 = code < BASE64_INDEX.length ? BASE64_INDEX[code] : -1;
    if (c1 === -1 || c2 === -1) break;
    let o = (c1 << 2) >>> 0;
    o |= (c2 & 0x30) >> 4;
    stra.push(String.fromCharCode(o));
    if (++olen >= len || off >= slen) break;
    code = str.charCodeAt(off++);
    const c3 = code < BASE64_INDEX.length ? BASE64_INDEX[code] : -1;
    if (c3 === -1) break;
    o = ((c2 & 0x0f) << 4) >>> 0;
    o |= (c3 & 0x3c) >> 2;
    stra.push(String.fromCharCode(o));
    if (++olen >= len || off >= slen) break;
    code = str.charCodeAt(off++);
    const c4 = code < BASE64_INDEX.length ? BASE64_INDEX[code] : -1;
    o = ((c3 & 0x03) << 6) >>> 0;
    o |= c4;
    stra.push(String.fromCharCode(o));
    ++olen;
  }
  const buffa = [];
  for (off = 0; off < olen; off++) buffa.push(stra[off].charCodeAt(0));
  return Buffer.from(buffa);
}

module.exports = {
  encode,
  decode
};