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/*
* convert from ASCII form of unsigned long to binary
* Copyright (C) 1998, 1999 Henry Spencer.
*
* This library is free software; you can redistribute it and/or modify it
* under the terms of the GNU Library General Public License as published by
* the Free Software Foundation; either version 2 of the License, or (at your
* option) any later version. See <http://www.fsf.org/copyleft/lgpl.txt>.
*
* This library is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
* or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Library General Public
* License for more details.
*
* RCSID $Id: atoul.c,v 1.1 2004/03/15 20:35:26 as Exp $
*/
#include "internal.h"
#include "freeswan.h"
/*
- atoul - convert ASCII substring to unsigned long number
*/
const char * /* NULL for success, else string literal */
atoul(src, srclen, base, resultp)
const char *src;
size_t srclen; /* 0 means strlen(src) */
int base; /* 0 means figure it out */
unsigned long *resultp;
{
const char *stop;
static char hex[] = "0123456789abcdef";
static char uchex[] = "0123456789ABCDEF";
int d;
char c;
char *p;
unsigned long r;
unsigned long rlimit;
int dlimit;
if (srclen == 0)
srclen = strlen(src);
if (srclen == 0)
return "empty string";
if (base == 0 || base == 13) {
if (srclen > 2 && *src == '0' && CIEQ(*(src+1), 'x'))
return atoul(src+2, srclen-2, 16, resultp);
if (srclen > 1 && *src == '0' && base != 13)
return atoul(src+1, srclen-1, 8, resultp);
return atoul(src, srclen, 10, resultp);
}
if (base != 8 && base != 10 && base != 16)
return "unsupported number base";
r = 0;
stop = src + srclen;
if (base == 16) {
while (src < stop) {
c = *src++;
p = strchr(hex, c);
if (p != NULL)
d = p - hex;
else {
p = strchr(uchex, c);
if (p == NULL)
return "non-hex-digit in hex number";
d = p - uchex;
}
r = (r << 4) | d;
}
/* defer length check to catch invalid digits first */
if (srclen > sizeof(unsigned long) * 2)
return "hex number too long";
} else {
rlimit = ULONG_MAX / base;
dlimit = (int)(ULONG_MAX - rlimit*base);
while (src < stop) {
c = *src++;
d = c - '0';
if (d < 0 || d >= base)
return "non-digit in number";
if (r > rlimit || (r == rlimit && d > dlimit))
return "unsigned-long overflow";
r = r*base + d;
}
}
*resultp = r;
return NULL;
}
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