Function char_to_digit_value

test-app/runtime/src/main/cpp/ada/ada.cpp:7999–8003

constexpr uint32_t initial_n = 128;

static constexpr int32_t char_to_digit_value(char value) {
  if (value >= 'a' && value <= 'z') return value - 'a';
  if (value >= '0' && value <= '9') return value - '0' + 26;
  return -1;
}

static constexpr char digit_to_char(int32_t digit) {
  return digit < 26 ? char(digit + 97) : char(digit + 22);