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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: strtol.c,v 1.2.2.1 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 a long integer.
*
* Ignores `locale' stuff. Assumes that the upper and lower case
* alphabets and digits are each contiguous.
*/
long
strtol(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;
/*
* Skip white space and pick up leading +/- sign if any.
* If base is 0, allow 0x for hex and 0 for octal, else
* assume decimal; if base is already 16, allow 0x.
*/
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;
/*
* Compute the cutoff value between legal numbers and illegal
* numbers. That is the largest legal value, divided by the
* base. An input number that is greater than this value, if
* followed by a legal input character, is too big. One that
* is equal to this value may be valid or not; the decision
* about this is done as outlined below.
*
* Overflow detections works as follows:
*
* As:
* acc_old <= cutoff
* then:
* acc_old * base <= 0x80000000 (unsigned)
* then:
* acc_old * base + c <= 0x80000000 + c
* or:
* acc_new <= 0x80000000 + 35
*
* i.e. carry from MSB (by calculating acc_new) is impossible
* and we can check result directly:
*
* if (acc_new > 0x80000000) then overflow
*
* Set any if any `digits' consumed; make it negative to indicate
* overflow.
*/
#if LONG_MIN != -LONG_MAX - 1
# error "This implementation of strtol() does not work on this platform."
#endif
switch (base) {
case 10:
cutoff = ((unsigned long)LONG_MAX + 1) / 10;
break;
case 16:
cutoff = ((unsigned long)LONG_MAX + 1) / 16;
break;
case 8:
cutoff = ((unsigned long)LONG_MAX + 1) / 8;
break;
case 2:
cutoff = ((unsigned long)LONG_MAX + 1) / 2;
break;
default:
cutoff = ((unsigned long)LONG_MAX + 1) / 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;
if (acc > (unsigned long)LONG_MAX + 1)
any = -1;
else
any = 1;
}
if (endptr) {
if (any)
*endptr = (char *)nptr - 1;
else if (flag & FL_0X)
*endptr = (char *)nptr - 2;
}
if (any < 0) {
acc = (flag & FL_NEG) ? LONG_MIN : LONG_MAX;
errno = ERANGE;
} else if (flag & FL_NEG) {
acc = -acc;
} else if ((signed long)acc < 0) {
acc = LONG_MAX;
errno = ERANGE;
}
return (acc);
}
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