87 lines
1.7 KiB
C
87 lines
1.7 KiB
C
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/* $NetBSD: strtoul.c,v 1.4 1999/11/29 22:51:19 simonb Exp $ */
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#include <sys/param.h>
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#include <lib/libkern/libkern.h>
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#ifndef ULONG_MAX
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#define ULONG_MAX ((u_long)(~0L)) /* 0xFFFFFFFF */
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#endif
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u_long
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strtoul(s, ptr, base)
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const char *s;
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char **ptr;
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int base;
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{
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u_long total = 0;
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u_int digit;
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const char *start=s;
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int did_conversion=0;
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int overflow = 0;
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int negate = 0;
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u_long maxdiv, maxrem;
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if (s == NULL) {
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if (!ptr)
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*ptr = (char *)start;
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return 0L;
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}
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while (*s == ' ')
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s++;
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if (*s == '+')
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s++;
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else if (*s == '-')
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s++, negate = 1;
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if (base==0 || base==16) { /* the 'base==16' is for handling 0x */
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int tmp;
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/*
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* try to infer base from the string
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*/
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if (*s != '0')
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tmp = 10; /* doesn't start with 0 - assume decimal */
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else if (s[1] == 'X' || s[1] == 'x')
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tmp = 16, s += 2; /* starts with 0x or 0X - hence hex */
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else
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tmp = 8; /* starts with 0 - hence octal */
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if (base==0)
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base = (int)tmp;
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}
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maxdiv = ULONG_MAX / base;
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maxrem = ULONG_MAX % base;
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while ((digit = *s) != '\0') {
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if (digit >= '0' && digit < ('0' + min(base, 10)))
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digit -= '0';
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else
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if (base > 10) {
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if (digit >= 'a' && digit < ('a'+(base-10)))
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digit = digit - 'a' + 10;
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else if (digit >= 'A' && digit < ('A'+(base-10)))
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digit = digit - 'A' + 10;
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else
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break;
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}
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else
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break;
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did_conversion = 1;
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if (total > maxdiv
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|| (total == maxdiv && digit > maxrem))
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overflow = 1;
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total = (total * base) + digit;
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s++;
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}
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if (overflow) {
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if (ptr != NULL)
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*ptr = (char *)s;
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return (ULONG_MAX);
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}
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if (ptr != NULL)
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*ptr = (char *) ((did_conversion) ? (char *)s : (char *)start);
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return negate ? -total : total;
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}
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/* End of strtoul.c */
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