apps/plugins/lua/strtoul.c

   1 #include "rocklibc.h"
   2
   3 unsigned long int strtoul(const char *ptr, char **endptr, int base)
   4 {
   5   int neg = 0, overflow = 0;
   6   unsigned long int v=0;
   7   const char* orig;
   8   const char* nptr=ptr;
   9
  10   while(isspace(*nptr)) ++nptr;
  11
  12   if (*nptr == '-') { neg=1; nptr++; }
  13   else if (*nptr == '+') ++nptr;
  14   orig=nptr;
  15   if (base==16 && nptr[0]=='0') goto skip0x;
  16   if (base) {
  17     register unsigned int b=base-2;
  18     if (__unlikely(b>34)) { errno=EINVAL; return 0; }
  19   } else {
  20     if (*nptr=='0') {
  21       base=8;
  22 skip0x:
  23       if ((nptr[1]=='x'||nptr[1]=='X') && isxdigit(nptr[2])) {
  24         nptr+=2;
  25         base=16;
  26       }
  27     } else
  28       base=10;
  29   }
  30   while(__likely(*nptr)) {
  31     register unsigned char c=*nptr;
  32     c=(c>='a'?c-'a'+10:c>='A'?c-'A'+10:c<='9'?c-'0':0xff);
  33     if (__unlikely(c>=base)) break;     /* out of base */
  34     {
  35       register unsigned long x=(v&0xff)*base+c;
  36       register unsigned long w=(v>>8)*base+(x>>8);
  37       if (w>(ULONG_MAX>>8)) overflow=1;
  38       v=(w<<8)+(x&0xff);
  39     }
  40     ++nptr;
  41   }
  42   if (__unlikely(nptr==orig)) {         /* no conversion done */
  43     nptr=ptr;
  44     errno=EINVAL;
  45     v=0;
  46   }
  47   if (endptr) *endptr=(char *)nptr;
  48   if (overflow) {
  49     errno=ERANGE;
  50     return ULONG_MAX;
  51   }
  52   return (neg?-v:v);
  53 }