stringTextToListHexPrefix function

List stringTextToListHexPrefix(String string)

Implementation

List stringTextToListHexPrefix(String string) {
  List listDec = string.runes.toList();
  List listHex = [];
  int symbol6Hex = 0;
  int textLength = 2;
  int prefixLength = 0;

  for (int a = 0; a < listDec.length; a++) {
    String stringHex = listDec[a].toRadixString(16);
    stringHex = isNotEven(stringHex);
    if (stringHex.length > 3) {
      /// If the hexadecimal value is more than three characters long, the following happens: First the prefix is created. For this the current counter
      /// of the loop is added with textlength and then multiplied by 2, because decryption is done in single bytes. The number 1 and 2 indicate how
      /// long the hexadecimal value is. Second we add the prefix to the first position or after the last prefix. Then the length of the prefix is
      /// added to the current value, the textLength is increased by 1 or 2 depending on how long the symbol is, and finally the counter for the
      /// six-digit hexadecimal values is increased if this was one.
      List prefixList =
          prefixInt((a + textLength) * 2, stringHex.length == 4 ? 1 : 2);
      listHex.insertAll(prefixLength, prefixList);

      prefixLength += prefixList.length;
      textLength += stringHex.length == 4 ? 1 : 2;
      symbol6Hex += stringHex.length == 4 ? 0 : 1;
    }

    listHex.add(stringHex);
  }

  List prefixTextLength = prefixInt(listDec.length + symbol6Hex, 0);

  /// First the length of the text is added.
  listHex.insertAll(0, prefixTextLength);

  /// The semicolon is inserted so that you know where the last symbol is when decoding.
  listHex.insert(prefixLength + prefixTextLength.length, "3b");
  return bigIntHexList(listHex);
}