net-snmp 5.7
strtoul.c
00001 /*
00002  * Copyright (c) 1990, 1993
00003  *      The Regents of the University of California.  All rights reserved.
00004  *
00005  * Redistribution and use in source and binary forms, with or without
00006  * modification, are permitted provided that the following conditions
00007  * are met:
00008  * 1. Redistributions of source code must retain the above copyright
00009  *        notice, this list of conditions and the following disclaimer.
00010  * 2. Redistributions in binary form must reproduce the above copyright
00011  *        notice, this list of conditions and the following disclaimer in the
00012  *        documentation and/or other materials provided with the distribution.
00013  * 3. Neither the name of the University nor the names of its contributors
00014  *        may be used to endorse or promote products derived from this software
00015  *        without specific prior written permission.
00016  *
00017  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
00018  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
00019  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
00020  * ARE DISCLAIMED.      IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
00021  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
00022  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
00023  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
00024  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
00025  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
00026  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
00027  * SUCH DAMAGE.
00028  */
00029 
00030 #include <net-snmp/net-snmp-config.h>
00031 
00032 #if defined(LIBC_SCCS) && !defined(lint)
00033 static char     sccsid[] = "@(#)strtoul.c   8.1 (Berkeley) 6/4/93";
00034 #endif                          /* LIBC_SCCS and not lint */
00035 
00036 #if HAVE_LIMITS_H
00037 #include <limits.h>
00038 #endif
00039 #include <ctype.h>
00040 #include <errno.h>
00041 #if HAVE_STDLIB_H
00042 #include <stdlib.h>
00043 #endif
00044 
00045 /*
00046  * Convert a string to an unsigned long integer.
00047  *
00048  * Ignores `locale' stuff.  Assumes that the upper and lower case
00049  * alphabets and digits are each contiguous.
00050  */
00051 unsigned long
00052 strtoul(const char *nptr, char **endptr, int base)
00053 {
00054     const char     *s = nptr;
00055     unsigned long   acc;
00056     unsigned char   c;
00057     unsigned long   cutoff;
00058     int             neg = 0, any, cutlim;
00059 
00060     /*
00061      * See strtol for comments as to the logic used.
00062      */
00063     do {
00064         c = *s++;
00065     } while (isspace(c));
00066     if (c == '-') {
00067         neg = 1;
00068         c = *s++;
00069     } else if (c == '+')
00070         c = *s++;
00071     if ((base == 0 || base == 16) && c == '0' && (*s == 'x' || *s == 'X')) {
00072         c = s[1];
00073         s += 2;
00074         base = 16;
00075     }
00076     if (base == 0)
00077         base = c == '0' ? 8 : 10;
00078     cutoff = (unsigned long) ULONG_MAX / (unsigned long) base;
00079     cutlim = (unsigned long) ULONG_MAX % (unsigned long) base;
00080     for (acc = 0, any = 0;; c = *s++) {
00081         if (!isascii(c))
00082             break;
00083         if (isdigit(c))
00084             c -= '0';
00085         else if (isalpha(c))
00086             c -= isupper(c) ? 'A' - 10 : 'a' - 10;
00087         else
00088             break;
00089         if (c >= base)
00090             break;
00091         if (any < 0 || acc > cutoff || (acc == cutoff && c > cutlim))
00092             any = -1;
00093         else {
00094             any = 1;
00095             acc *= base;
00096             acc += c;
00097         }
00098     }
00099     if (any < 0) {
00100         acc = ULONG_MAX;
00101         errno = ERANGE;
00102     } else if (neg)
00103         acc = -acc;
00104     if (endptr != 0)
00105         *endptr = (char *) (any ? s - 1 : nptr);
00106     return (acc);
00107 }