/**
 * @module AccountName
 */
import * as bs58 from 'bs58';

import * as Long from 'long';

const { PublicKey } = require('./ecc');

/**
    Hashes a public key to a valid FIOIO account name.
    @arg {string} pubkey
    @return {string} valid FIOIO account name
*/
export function accountHash(pubkey : string) : string {
    if(!PublicKey.isValid(pubkey, 'EOS')) {
        throw new TypeError('invalid public key');
    }

    pubkey = pubkey.substring('EOS'.length, pubkey.length);

    const decoded58 = bs58.decode(pubkey);
    const long = shortenKey(decoded58);

    const output = stringFromUInt64T(long);
    return output;
}

function shortenKey(key : [number]) : any {
  var res = Long.fromValue (0, true);
  var temp = Long.fromValue (0, true);
  var toShift = 0;
  var i = 1;
  var len = 0;

  while (len <= 12) {
      //assert(i < 33, "Means the key has > 20 bytes with trailing zeroes...")
      temp = Long.fromValue(key[i], true).and(len == 12 ? 0x0f : 0x1f);
      if (temp == 0) {
          i+=1
          continue
      }
      if (len == 12){
        toShift = 0;
      }
      else{
        toShift = (5 * (12 - len) - 1);
      }
      temp = Long.fromValue(temp, true).shiftLeft(toShift);

      res = Long.fromValue(res, true).or(temp);
      len+=1
      i+=1
  }

  return res;
}

function stringFromUInt64T(temp : any) : string{
  var charmap = ".12345abcdefghijklmnopqrstuvwxyz".split('');

  var str = new Array(13);
  str[12] = charmap[Long.fromValue(temp, true).and(0x0f)];

  temp = Long.fromValue(temp, true).shiftRight(4);
  for (var i = 1; i <= 12; i++) {
      var c = charmap[Long.fromValue(temp, true).and(0x1f)];
      str[12 - i] = c;
      temp = Long.fromValue(temp, true).shiftRight(5);
  }
  var result = str.join('');
  if (result.length > 12) {
      result = result.substring(0, 12);
  }
  return result;
}

测试

describe('accountname', () => {
    it('matches', () => {
        const samplekey = "EOS7isxEua78KPVbGzKemH4nj2bWE52gqj8Hkac3tc7jKNvpfWzYS";
        const accountHash = AccountName.accountHash(samplekey);
        expect(accountHash).toEqual('p4hc54ppiofx');
    })
})

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