z85-codec/dist/z85-codec.cjs.development.js

Z85 - ZeroMQ's ascii85 encoding format

'use strict';

Object.defineProperty(exports, '__esModule', { value: true });

var encoder = ['0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z', 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z', '.', '-', ':', '+', '=', '^', '!', '/', '*', '?', '&', '<', '>', '(', ')', '[', ']', '{', '}', '@', '%', '$', '#'];
var decoder = [0x00, 0x44, 0x00, 0x54, 0x53, 0x52, 0x48, 0x00, 0x4b, 0x4c, 0x46, 0x41, 0x00, 0x3f, 0x3e, 0x45, 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x40, 0x00, 0x49, 0x42, 0x4a, 0x47, 0x51, 0x24, 0x25, 0x26, 0x27, 0x28, 0x29, 0x2a, 0x2b, 0x2c, 0x2d, 0x2e, 0x2f, 0x30, 0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37, 0x38, 0x39, 0x3a, 0x3b, 0x3c, 0x3d, 0x4d, 0x00, 0x4e, 0x43, 0x00, 0x00, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f, 0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17, 0x18, 0x19, 0x1a, 0x1b, 0x1c, 0x1d, 0x1e, 0x1f, 0x20, 0x21, 0x22, 0x23, 0x4f, 0x00, 0x50, 0x00, 0x00];
/**
 *  Encode data with the Z85 codec
 *
 * @param data - data to encode.
 * Length needs to be divisible by 4 otherwise null is returned.
 * String needs to be encoded in UTF-8.
 * @returns encoded data as string or null when encoding is not possible
 * @see {@link https://github.com/zeromq/rfc/blob/master/src/spec_32.c} for the used reference implementation
 */

function encode(data) {
  if (data.length % 4) return null;
  var encoded = '';
  var byteNbr = 0;
  var value = 0;
  var dataIndexAccess = typeof data === 'string' ? function (data, index) {
    return data.charCodeAt(index);
  } : function (data, index) {
    return data[index];
  };

  while (byteNbr < data.length) {
    value = value * 256 + dataIndexAccess(data, byteNbr++);

    if (byteNbr % 4 === 0) {
      var divisor = 52200625; // 85 * 85 * 85 * 85

      while (divisor >= 1) {
        encoded += encoder[Math.floor(value / divisor) % 85];
        divisor /= 85;
      }

      value = 0;
    }
  }

  return encoded;
}
/**
 *  Decode data with the Z85 codec
 *
 * @param string - string to decode.
 * Length needs to be divisible by 5 otherwise null is returned.
 * Needs to be encoded in UTF-8.
 * @returns decoded string as Uint8Array or null when decoding is not possible
 * @see {@link https://github.com/zeromq/rfc/blob/master/src/spec_32.c} for the used reference implementation
 */

function decode(string) {
  if (string.length % 5) return null;
  var decoded = new Uint8Array(string.length * 4 / 5);
  var byteNbr = 0;
  var charNbr = 0;
  var value = 0;

  while (charNbr < string.length) {
    if (!encoder.includes(string.charAt(charNbr))) return null; // invalid character

    var index = string.charCodeAt(charNbr++) - 32;
    value = value * 85 + decoder[index];

    if (charNbr % 5 === 0) {
      var divisor = 16777216; // 256 * 256 * 256

      while (divisor >= 1) {
        decoded[byteNbr++] = value / divisor % 256;
        divisor /= 256;
      }

      value = 0;
    }
  }

  return decoded;
}

exports.decode = decode;
exports.encode = encode;
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