Method GetBaseN

Int.cpp:1073–1111

// ------------------------------------------------

std::string Int::GetBaseN(int n,char *charset) {

  std::string ret;

  Int N(this);
  int isNegative = N.IsNegative();
  if (isNegative) N.Neg();

  // TODO: compute max digit
  unsigned char digits[1024];
  memset(digits, 0, sizeof(digits));

  int digitslen = 1;
  for (int i = 0; i < NB64BLOCK * 8; i++) {
    unsigned int carry = N.GetByte(NB64BLOCK*8 - i - 1);
    for (int j = 0; j < digitslen; j++) {
      carry += (unsigned int)(digits[j]) << 8;
      digits[j] = (unsigned char)(carry % n);
      carry /= n;
    }
    while (carry > 0) {
      digits[digitslen++] = (unsigned char)(carry % n);
      carry /= n;
    }
  }

  // reverse
  if (isNegative)
    ret.push_back('-');

  for (int i = 0; i < digitslen; i++)
    ret.push_back(charset[digits[digitslen - 1 - i]]);

  if (ret.length() == 0)
    ret.push_back('0');

  return ret;

}

// ------------------------------------------------