mod.js

/*
    This file is part of web3.js.

    web3.js is free software: you can redistribute it and/or modify
    it under the terms of the GNU Lesser General Public License as published by
    the Free Software Foundation, either version 3 of the License, or
    (at your option) any later version.

    web3.js is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU Lesser General Public License for more details.

    You should have received a copy of the GNU Lesser General Public License
    along with web3.js.  If not, see <http://www.gnu.org/licenses/>.
*/

import {
  BN as BigNumber,
  utils,
} from "./deps.js";

var leftPad = function (string, bytes) {
  var result = string;
  while (result.length < bytes * 2) {
    result = "0" + result;
  }
  return result;
};

/**
 * Prepare an IBAN for mod 97 computation by moving the first 4 chars to the end and transforming the letters to
 * numbers (A = 10, B = 11, ..., Z = 35), as specified in ISO13616.
 *
 * @method iso13616Prepare
 * @param {String} iban the IBAN
 * @returns {String} the prepared IBAN
 */
var iso13616Prepare = function (iban) {
  var A = "A".charCodeAt(0);
  var Z = "Z".charCodeAt(0);

  iban = iban.toUpperCase();
  iban = iban.substr(4) + iban.substr(0, 4);

  return iban.split("").map(function (n) {
    var code = n.charCodeAt(0);
    if (code >= A && code <= Z) {
      // A = 10, B = 11, ... Z = 35
      return code - A + 10;
    } else {
      return n;
    }
  }).join("");
};

/**
 * Calculates the MOD 97 10 of the passed IBAN as specified in ISO7064.
 *
 * @method mod9710
 * @param {String} iban
 * @returns {Number}
 */
var mod9710 = function (iban) {
  var remainder = iban,
    block;

  while (remainder.length > 2) {
    block = remainder.slice(0, 9);
    remainder = parseInt(block, 10) % 97 + remainder.slice(block.length);
  }

  return parseInt(remainder, 10) % 97;
};

/**
 * This prototype should be used to create iban object from iban correct string
 *
 * @param {String} iban
 */
var Iban = function Iban(iban) {
  this._iban = iban;
};

/**
 * This method should be used to create an ethereum address from a direct iban address
 *
 * @method toAddress
 * @param {String} iban address
 * @return {String} the ethereum address
 */
Iban.toAddress = function (ib) {
  ib = new Iban(ib);

  if (!ib.isDirect()) {
    throw new Error("IBAN is indirect and can't be converted");
  }

  return ib.toAddress();
};

/**
 * This method should be used to create iban address from an ethereum address
 *
 * @method toIban
 * @param {String} address
 * @return {String} the IBAN address
 */
Iban.toIban = function (address) {
  return Iban.fromAddress(address).toString();
};

/**
 * This method should be used to create iban object from an ethereum address
 *
 * @method fromAddress
 * @param {String} address
 * @return {Iban} the IBAN object
 */
Iban.fromAddress = function (address) {
  if (!utils.isAddress(address)) {
    throw new Error("Provided address is not a valid address: " + address);
  }

  address = address.replace("0x", "").replace("0X", "");

  var asBn = new BigNumber(address, 16);
  var base36 = asBn.toString(36);
  var padded = leftPad(base36, 15);
  return Iban.fromBban(padded.toUpperCase());
};

/**
 * Convert the passed BBAN to an IBAN for this country specification.
 * Please note that <i>"generation of the IBAN shall be the exclusive responsibility of the bank/branch servicing the account"</i>.
 * This method implements the preferred algorithm described in http://en.wikipedia.org/wiki/International_Bank_Account_Number#Generating_IBAN_check_digits
 *
 * @method fromBban
 * @param {String} bban the BBAN to convert to IBAN
 * @returns {Iban} the IBAN object
 */
Iban.fromBban = function (bban) {
  var countryCode = "XE";

  var remainder = mod9710(iso13616Prepare(countryCode + "00" + bban));
  var checkDigit = ("0" + (98 - remainder)).slice(-2);

  return new Iban(countryCode + checkDigit + bban);
};

/**
 * Should be used to create IBAN object for given institution and identifier
 *
 * @method createIndirect
 * @param {Object} options, required options are "institution" and "identifier"
 * @return {Iban} the IBAN object
 */
Iban.createIndirect = function (options) {
  return Iban.fromBban("ETH" + options.institution + options.identifier);
};

/**
 * This method should be used to check if given string is valid iban object
 *
 * @method isValid
 * @param {String} iban string
 * @return {Boolean} true if it is valid IBAN
 */
Iban.isValid = function (iban) {
  var i = new Iban(iban);
  return i.isValid();
};

/**
 * Should be called to check if iban is correct
 *
 * @method isValid
 * @returns {Boolean} true if it is, otherwise false
 */
Iban.prototype.isValid = function () {
  return /^XE[0-9]{2}(ETH[0-9A-Z]{13}|[0-9A-Z]{30,31})$/.test(this._iban) &&
    mod9710(iso13616Prepare(this._iban)) === 1;
};

/**
 * Should be called to check if iban number is direct
 *
 * @method isDirect
 * @returns {Boolean} true if it is, otherwise false
 */
Iban.prototype.isDirect = function () {
  return this._iban.length === 34 || this._iban.length === 35;
};

/**
 * Should be called to check if iban number if indirect
 *
 * @method isIndirect
 * @returns {Boolean} true if it is, otherwise false
 */
Iban.prototype.isIndirect = function () {
  return this._iban.length === 20;
};

/**
 * Should be called to get iban checksum
 * Uses the mod-97-10 checksumming protocol (ISO/IEC 7064:2003)
 *
 * @method checksum
 * @returns {String} checksum
 */
Iban.prototype.checksum = function () {
  return this._iban.substr(2, 2);
};

/**
 * Should be called to get institution identifier
 * eg. XREG
 *
 * @method institution
 * @returns {String} institution identifier
 */
Iban.prototype.institution = function () {
  return this.isIndirect() ? this._iban.substr(7, 4) : "";
};

/**
 * Should be called to get client identifier within institution
 * eg. GAVOFYORK
 *
 * @method client
 * @returns {String} client identifier
 */
Iban.prototype.client = function () {
  return this.isIndirect() ? this._iban.substr(11) : "";
};

/**
 * Should be called to get client direct address
 *
 * @method toAddress
 * @returns {String} ethereum address
 */
Iban.prototype.toAddress = function () {
  if (this.isDirect()) {
    var base36 = this._iban.substr(4);
    var asBn = new BigNumber(base36, 36);
    return utils.toChecksumAddress(asBn.toString(16, 20));
  }

  return "";
};

Iban.prototype.toString = function () {
  return this._iban;
};

export default Iban;