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Annotation of GNUtools/libg++/libiberty/strtoul.c, revision 1.1.1.1

1.1       root        1: /*
                      2:  * strtol : convert a string to long.
                      3:  *
                      4:  * Andy Wilson, 2-Oct-89.
                      5:  */
                      6: 
                      7: #include <errno.h>
                      8: #include <ctype.h>
                      9: #include <stdio.h>
                     10: #include "ansidecl.h"
                     11: 
                     12: #ifndef ULONG_MAX
                     13: #define        ULONG_MAX       ((unsigned long)(~0L))          /* 0xFFFFFFFF */
                     14: #endif
                     15: 
                     16: extern int errno;
                     17: 
                     18: unsigned long
                     19: strtoul(s, ptr, base)
                     20:      CONST char *s; char **ptr; int base;
                     21: {
                     22:   unsigned long total = 0;
                     23:   unsigned digit;
                     24:   CONST char *start=s;
                     25:   int did_conversion=0;
                     26:   int overflow = 0;
                     27:   int negate = 0;
                     28:   unsigned long maxdiv, maxrem;
                     29: 
                     30:   if (s==NULL)
                     31:     {
                     32:       errno = ERANGE;
                     33:       if (!ptr)
                     34:        *ptr = (char *)start;
                     35:       return 0L;
                     36:     }
                     37: 
                     38:   while (isspace(*s))
                     39:     s++;
                     40:   if (*s == '+')
                     41:     s++;
                     42:   else if (*s == '-')
                     43:     s++, negate = 1;
                     44:   if (base==0 || base==16) /*  the 'base==16' is for handling 0x */
                     45:     {
                     46:       int tmp;
                     47: 
                     48:       /*
                     49:        * try to infer base from the string
                     50:        */
                     51:       if (*s != '0')
                     52:         tmp = 10;      /* doesn't start with 0 - assume decimal */
                     53:       else if (s[1] == 'X' || s[1] == 'x')
                     54:        tmp = 16, s += 2; /* starts with 0x or 0X - hence hex */
                     55:       else
                     56:        tmp = 8;        /* starts with 0 - hence octal */
                     57:       if (base==0)
                     58:        base = (int)tmp;
                     59:     }
                     60: 
                     61:   maxdiv = ULONG_MAX / base;
                     62:   maxrem = ULONG_MAX % base;
                     63: 
                     64:   while ((digit = *s) != '\0')
                     65:     {
                     66:       if (digit >= '0' && digit < ('0'+base))
                     67:        digit -= '0';
                     68:       else
                     69:        if (base > 10)
                     70:          {
                     71:            if (digit >= 'a' && digit < ('a'+(base-10)))
                     72:              digit = digit - 'a' + 10;
                     73:            else if (digit >= 'A' && digit < ('A'+(base-10)))
                     74:              digit = digit - 'A' + 10;
                     75:            else
                     76:              break;
                     77:          }
                     78:        else
                     79:          break;
                     80:       did_conversion = 1;
                     81:       if (total > maxdiv
                     82:          || (total == maxdiv && digit > maxrem))
                     83:        overflow = 1;
                     84:       total = (total * base) + digit;
                     85:       s++;
                     86:     }
                     87:   if (overflow)
                     88:     {
                     89:       errno = ERANGE;
                     90:       if (ptr != NULL)
                     91:        *ptr = (char *)s;
                     92:       return (ULONG_MAX);
                     93:     }
                     94:   if (ptr != NULL)
                     95:     *ptr = (char *) ((did_conversion) ? (char *)s : (char *)start);
                     96:   return negate ? -total : total;
                     97: }

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