nacl-util.js

import Base64 from '../base64-js'

export const decodeUTF8 = (str) => {
  var utf8 = [];
  for (var i = 0; i < str.length; i++) {
    var charcode = str.charCodeAt(i);
    if (charcode < 0x80) utf8.push(charcode);
    else if (charcode < 0x800) {
      utf8.push(0xc0 | (charcode >> 6),
        0x80 | (charcode & 0x3f));
    }
    else if (charcode < 0xd800 || charcode >= 0xe000) {
      utf8.push(0xe0 | (charcode >> 12),
        0x80 | ((charcode >> 6) & 0x3f),
        0x80 | (charcode & 0x3f));
    }
    // surrogate pair
    else {
      i++;
      // UTF-16 encodes 0x10000-0x10FFFF by
      // subtracting 0x10000 and splitting the
      // 20 bits of 0x0-0xFFFFF into two halves
      charcode = 0x10000 + (((charcode & 0x3ff) << 10)
        | (str.charCodeAt(i) & 0x3ff))
      utf8.push(0xf0 | (charcode >> 18),
        0x80 | ((charcode >> 12) & 0x3f),
        0x80 | ((charcode >> 6) & 0x3f),
        0x80 | (charcode & 0x3f));
    }
  }
  return utf8;
}

export const encodeUTF8 = (data) => { // array of bytes
  var str = '',
    i;

  for (i = 0; i < data.length; i++) {
    var value = data[i];

    if (value < 0x80) {
      str += String.fromCharCode(value);
    } else if (value > 0xBF && value < 0xE0) {
      str += String.fromCharCode((value & 0x1F) << 6 | data[i + 1] & 0x3F);
      i += 1;
    } else if (value > 0xDF && value < 0xF0) {
      str += String.fromCharCode((value & 0x0F) << 12 | (data[i + 1] & 0x3F) << 6 | data[i + 2] & 0x3F);
      i += 2;
    } else {
      // surrogate pair
      var charCode = ((value & 0x07) << 18 | (data[i + 1] & 0x3F) << 12 | (data[i + 2] & 0x3F) << 6 | data[i + 3] & 0x3F) - 0x010000;

      str += String.fromCharCode(charCode >> 10 | 0xD800, charCode & 0x03FF | 0xDC00);
      i += 3;
    }
  }

  return str;
}

export const encodeBase64 = (data) => Base64.fromByteArray(data)

export const decodeBase64 = (str) => Base64.toByteArray(str)