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/*
* Copyright (c) 1990, 1993
* The Regents of the University of California. All rights reserved.
* Copyright (c) 2005, Dmitry Xmelkov
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* $Id: strtoul.c,v 1.3.2.1 2005/01/25 10:40:06 joerg_wunsch Exp $
*/
#include <limits.h>
#include <ctype.h>
#include <errno.h>
#include <stdlib.h>
/*
* Convert a string to an unsigned long integer.
*
* Ignores `locale' stuff. Assumes that the upper and lower case
* alphabets and digits are each contiguous.
*/
unsigned long
strtoul(nptr, endptr, base)
const char *nptr;
char **endptr;
register int base;
{
register unsigned long acc;
register unsigned char c;
register unsigned long cutoff;
register signed char any;
unsigned char flag = 0;
#define FL_NEG 0x01 /* number is negative */
#define FL_0X 0x02 /* number has a 0x prefix */
if (endptr)
*endptr = (char *)nptr;
if (base != 0 && (base < 2 || base > 36))
return 0;
/*
* See strtol for comments as to the logic used.
*/
do {
c = *nptr++;
} while (isspace(c));
if (c == '-') {
flag = FL_NEG;
c = *nptr++;
} else if (c == '+')
c = *nptr++;
if ((base == 0 || base == 16) &&
c == '0' && (*nptr == 'x' || *nptr == 'X')) {
c = nptr[1];
nptr += 2;
base = 16;
flag |= FL_0X;
}
if (base == 0)
base = c == '0' ? 8 : 10;
/*
* cutoff computation is similar to strtol().
*
* Description of the overflow detection logic used.
*
* First, let us assume an overflow.
*
* Result of `acc_old * base + c' is cut to 32 bits:
* acc_new <-- acc_old * base + c - 0x100000000
*
* `acc_old * base' is <= 0xffffffff (cutoff control)
*
* then: acc_new <= 0xffffffff + c - 0x100000000
*
* or: acc_new <= c - 1
*
* or: acc_new < c
*
* Second:
* if (no overflow) then acc * base + c >= c
* (or: acc_new >= c)
* is clear (alls are unsigned).
*
*/
switch (base) {
case 16: cutoff = ULONG_MAX / 16; break;
case 10: cutoff = ULONG_MAX / 10; break;
case 8: cutoff = ULONG_MAX / 8; break;
default: cutoff = ULONG_MAX / base;
}
for (acc = 0, any = 0;; c = *nptr++) {
if (c >= '0' && c <= '9')
c -= '0';
else if (c >= 'A' && c <= 'Z')
c -= 'A' - 10;
else if (c >= 'a' && c <= 'z')
c -= 'a' - 10;
else
break;
if (c >= base)
break;
if (any < 0)
continue;
if (acc > cutoff) {
any = -1;
continue;
}
acc = acc * base + c;
any = (c > acc) ? -1 : 1;
}
if (endptr) {
if (any)
*endptr = (char *)nptr - 1;
else if (flag & FL_0X)
*endptr = (char *)nptr - 2;
}
if (flag & FL_NEG)
acc = -acc;
if (any < 0) {
acc = ULONG_MAX;
errno = ERANGE;
}
return (acc);
}
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