reactos/lib/crtdll/old cruft/stdlib/strtoull.c

   1 /* Copyright (C) 1996 DJ Delorie, see COPYING.DJ for details */
   2 /* Copyright (C) 1994 DJ Delorie, see COPYING.DJ for details */
   3 #include <limits.h>
   4 #include <msvcrt/ctype.h>
   5 #include <msvcrt/errno.h>
   6 #include <msvcrt/stdlib.h>
   7 //#include <msvcrt/unconst.h>
   8
   9 /*
  10  * Convert a string to an unsigned long integer.
  11  *
  12  * Ignores `locale' stuff.  Assumes that the upper and lower case
  13  * alphabets and digits are each contiguous.
  14  */
  15 unsigned long
  16 strtoull(const char *nptr, char **endptr, int base)
  17 {
  18   const char *s = nptr;
  19   unsigned long acc;
  20   int c;
  21   unsigned long cutoff;
  22   int neg = 0, any, cutlim;
  23
  24   /*
  25    * See strtol for comments as to the logic used.
  26    */
  27   do {
  28     c = *s++;
  29   } while (isspace(c));
  30   if (c == '-')
  31   {
  32     neg = 1;
  33     c = *s++;
  34   }
  35   else if (c == '+')
  36     c = *s++;
  37   if ((base == 0 || base == 16) &&
  38       c == '0' && (*s == 'x' || *s == 'X'))
  39   {
  40     c = s[1];
  41     s += 2;
  42     base = 16;
  43   }
  44   if (base == 0)
  45     base = c == '0' ? 8 : 10;
  46   cutoff = (unsigned long)ULONG_MAX / base;
  47   cutlim = (unsigned long)ULONG_MAX % base;
  48   for (acc = 0, any = 0;; c = *s++)
  49   {
  50     if (isdigit(c))
  51       c -= '0';
  52     else if (isalpha(c))
  53       c -= isupper(c) ? 'A' - 10 : 'a' - 10;
  54     else
  55       break;
  56     if (c >= base)
  57       break;
  58     if (any < 0 || acc > cutoff || (acc == cutoff && c > cutlim))
  59       any = -1;
  60     else {
  61       any = 1;
  62       acc *= base;
  63       acc += c;
  64     }
  65   }
  66   if (any < 0)
  67   {
  68     acc = ULONG_MAX;
  69     errno = ERANGE;
  70   }
  71   else if (neg)
  72     acc = -acc;
  73   if (endptr != 0)
  74     *endptr = any ? (char *)s - 1 : (char *)nptr;
  75   return acc;
  76 }