dist/nvi/clib/strtoul.c

   1 /*      $NetBSD$ */
   2
   3 /*
   4  * Copyright (c) 1990, 1993
   5  *      The Regents of the University of California.  All rights reserved.
   6  *
   7  * Redistribution and use in source and binary forms, with or without
   8  * modification, are permitted provided that the following conditions
   9  * are met:
  10  * 1. Redistributions of source code must retain the above copyright
  11  *    notice, this list of conditions and the following disclaimer.
  12  * 2. Redistributions in binary form must reproduce the above copyright
  13  *    notice, this list of conditions and the following disclaimer in the
  14  *    documentation and/or other materials provided with the distribution.
  15  * 3. All advertising materials mentioning features or use of this software
  16  *    must display the following acknowledgement:
  17  *      This product includes software developed by the University of
  18  *      California, Berkeley and its contributors.
  19  * 4. Neither the name of the University nor the names of its contributors
  20  *    may be used to endorse or promote products derived from this software
  21  *    without specific prior written permission.
  22  *
  23  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  24  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  25  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  26  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  27  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  28  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  29  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  30  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  31  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  32  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  33  * SUCH DAMAGE.
  34  */
  35
  36 #include "config.h"
  37
  38 #if defined(LIBC_SCCS) && !defined(lint)
  39 static const char sccsid[] = "@(#)strtoul.c     8.1 (Berkeley) 6/4/93";
  40 #endif /* LIBC_SCCS and not lint */
  41
  42 #include <limits.h>
  43 #include <ctype.h>
  44 #include <errno.h>
  45 #include <stdlib.h>
  46
  47 /*
  48  * Convert a string to an unsigned long integer.
  49  *
  50  * Ignores `locale' stuff.  Assumes that the upper and lower case
  51  * alphabets and digits are each contiguous.
  52  *
  53  * PUBLIC: #ifndef HAVE_STRTOUL
  54  * PUBLIC: unsigned long strtoul __P((const char *, char **, int));
  55  * PUBLIC: #endif
  56  */
  57 unsigned long
  58 strtoul(const char *nptr, char **endptr, register int base)
  59 {
  60         register const char *s = nptr;
  61         register unsigned long acc;
  62         register int c;
  63         register unsigned long cutoff;
  64         register int neg = 0, any, cutlim;
  65
  66         /*
  67          * See strtol for comments as to the logic used.
  68          */
  69         do {
  70                 c = *s++;
  71         } while (isspace(c));
  72         if (c == '-') {
  73                 neg = 1;
  74                 c = *s++;
  75         } else if (c == '+')
  76                 c = *s++;
  77         if ((base == 0 || base == 16) &&
  78             c == '0' && (*s == 'x' || *s == 'X')) {
  79                 c = s[1];
  80                 s += 2;
  81                 base = 16;
  82         }
  83         if (base == 0)
  84                 base = c == '0' ? 8 : 10;
  85         cutoff = (unsigned long)ULONG_MAX / (unsigned long)base;
  86         cutlim = (unsigned long)ULONG_MAX % (unsigned long)base;
  87         for (acc = 0, any = 0;; c = *s++) {
  88                 if (isdigit(c))
  89                         c -= '0';
  90                 else if (isalpha(c))
  91                         c -= isupper(c) ? 'A' - 10 : 'a' - 10;
  92                 else
  93                         break;
  94                 if (c >= base)
  95                         break;
  96                 if (any < 0 || acc > cutoff || acc == cutoff && c > cutlim)
  97                         any = -1;
  98                 else {
  99                         any = 1;
 100                         acc *= base;
 101                         acc += c;
 102                 }
 103         }
 104         if (any < 0) {
 105                 acc = ULONG_MAX;
 106                 errno = ERANGE;
 107         } else if (neg)
 108                 acc = -acc;
 109         if (endptr != 0)
 110                 *endptr = (char *)(any ? s - 1 : nptr);
 111         return (acc);
 112 }