Function FormatExponent

include/sonic/internal/ftoa.h:827–863

}

static sonic_force_inline char* FormatExponent(F64Decimal v, char* out,
                                               unsigned cnt) {
  char* p = out + 1;
  char* end = FormatSignificand(v.sig, p, cnt);
  while (*(end - 1) == '0') end--;

  /* print decimal point if needed */
  *out = *p;
  if (end - p > 1) {
    *p = '.';
  } else {
    end--;
  }

  /* print the exponent */
  *end++ = 'e';
  int32_t exp = v.exp + (int32_t)cnt - 1;
  if (exp < 0) {
    *end++ = '-';
    exp = -exp;
  } else {
    *end++ = '+';
  }

  if (exp >= 100) {
    int32_t c = exp % 10;
    Copy2Digs(end, kDigits + 2 * (exp / 10));
    end[2] = (char)('0' + c);
    end += 3;
  } else if (exp >= 10) {
    Copy2Digs(end, kDigits + 2 * exp);
    end += 2;
  } else {
    *end++ = (char)('0' + exp);
  }
  return end;
}

static sonic_force_inline char* FormatDecimal(F64Decimal v, char* out,
                                              unsigned cnt) {