@dip1059/bitcoinjs-lib/src/cashaddr/convertBits.js

bitcoinjs-lib with some other btc based network support. Cloned from https://github.com/junderw/bitcoinjs-lib/tree/cashv5

'use strict';
// Copyright (c) 2017-2018 Emilio Almansi
// Copyright (c) 2017 Pieter Wuille
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE.
Object.defineProperty(exports, '__esModule', { value: true });
const validation_1 = require('./validation');
/**
 * Converts an array of integers made up of 'from' bits into an
 * array of integers made up of 'to' bits. The output array is
 * zero-padded if necessary, unless strict mode is true.
 * Throws a {@link ValidationError} if input is invalid.
 * Original by Pieter Wuille: https://github.com/sipa/bech32.
 *
 * @param {Uint8Array} data Array of integers made up of 'from' bits.
 * @param {number} from Length in bits of elements in the input array.
 * @param {number} to Length in bits of elements in the output array.
 * @param {bool} strictMode Require the conversion to be completed without padding.
 * @returns {Uint8Array}
 */
function convertBits(data, from, to, strictMode) {
  const length = strictMode
    ? Math.floor((data.length * from) / to)
    : Math.ceil((data.length * from) / to);
  const mask = (1 << to) - 1;
  const result = new Uint8Array(length);
  let index = 0;
  let accumulator = 0;
  let bits = 0;
  for (const value of data) {
    validation_1.validate(
      0 <= value && value >> from === 0,
      'Invalid value: ' + value + '.',
    );
    accumulator = (accumulator << from) | value;
    bits += from;
    while (bits >= to) {
      bits -= to;
      result[index] = (accumulator >> bits) & mask;
      ++index;
    }
  }
  if (!strictMode) {
    if (bits > 0) {
      result[index] = (accumulator << (to - bits)) & mask;
      ++index;
    }
  } else {
    validation_1.validate(
      bits < from && ((accumulator << (to - bits)) & mask) === 0,
      'Input cannot be converted to ' +
        to +
        ' bits without padding, but strict mode was used.',
    );
  }
  return result;
}
exports.convertBits = convertBits;