text: #include <fltKernel.h>
  #include <limits.h>
  
  _Check_return_
  _ACRTIMP long long __cdecl strtoll(_In_z_ char const *_String, _Out_opt_ _Deref_post_z_ char **_EndPtr, _In_ int _Radix)
  {
      const char *nptr = (const char *)_String;
      char **endptr = (char **)_EndPtr;
      int base = (int)_Radix;
  
      register const char *s = nptr;
      register long long acc;
      register int c;
      register long long cutoff;
      register int neg = 0, any, cutlim;
  
      /*
       * Skip white space and pick up leading +/- sign if any.
       * If base is 0, allow 0x for hex and 0 for octal, else
       * assume decimal; if base is already 16, allow 0x.
       */
      do
      {
          c = *s++;
      } while (isspace(c));
      if (c == '-')
      {
          neg = 1;
          c = *s++;
      }
      else if (c == '+')
          c = *s++;
      if ((base == 0 || base == 16) && c == '0' && (*s == 'x' || *s == 'X'))
      {
          c = s[1];
          s += 2;
          base = 16;
      }
      if (base == 0)
          base = c == '0' ? 8 : 10;
  
      /*
       * Compute the cutoff value between legal numbers and illegal
       * numbers.  That is the largest legal value, divided by the
       * base.  An input number that is greater than this value, if
       * followed by a legal input character, is too big.  One that
       * is equal to this value may be valid or not; the limit
       * between valid and invalid numbers is then based on the last
       * digit.  For instance, if the range for longs is
       * [-2147483648..2147483647] and the input base is 10,
       * cutoff will be set to 214748364 and cutlim to either
       * 7 (neg==0) or 8 (neg==1), meaning that if we have accumulated
       * a value > 214748364, or equal but the next digit is > 7 (or 8),
       * the number is too big, and we will return a range error.
       *
       * Set any if any `digits' consumed; make it negative to indicate
       * overflow.
       */
      cutoff = neg ? -(long long)LLONG_MIN : LLONG_MAX;
      cutlim = cutoff % (long long)base;
      cutoff /= (long long)base;
      for (acc = 0, any = 0;; c = *s++)
      {
          if (isdigit(c))
              c -= '0';
          else if (isalpha(c))
              c -= isupper(c) ? 'A' - 10 : 'a' - 10;
          else
              break;
          if (c >= base)
              break;
          if (any < 0 || acc > cutoff || (acc == cutoff && c > cutlim))
              any = -1;
          else
          {
              any = 1;
              acc *= base;
              acc += c;
          }
      }
      if (any < 0)
      {
          acc = neg ? LLONG_MIN : LLONG_MAX;
          errno = ERANGE;
      }
      else if (neg)
          acc = -acc;
      if (endptr != 0)
          *endptr = (char *)(any ? s - 1 : nptr);
      return (acc);
  }
  