openbsd-compat/strtoul.c

   1 /* OPENBSD ORIGINAL: lib/libc/stdlib/strtoul.c */
   2
   3 /*
   4  * Copyright (c) 1990 Regents of the University of California.
   5  * 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. Neither the name of the University nor the names of its contributors
  16  *    may be used to endorse or promote products derived from this software
  17  *    without specific prior written permission.
  18  *
  19  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  29  * SUCH DAMAGE.
  30  */
  31
  32 #include "includes.h"
  33 #ifndef HAVE_STRTOUL
  34
  35 #if defined(LIBC_SCCS) && !defined(lint)
  36 static char *rcsid = "$OpenBSD: strtoul.c,v 1.5 2003/06/02 20:18:38 millert Exp $";
  37 #endif /* LIBC_SCCS and not lint */
  38
  39 #include <ctype.h>
  40 #include <errno.h>
  41 #include <limits.h>
  42 #include <stdlib.h>
  43
  44 /*
  45  * Convert a string to an unsigned long integer.
  46  *
  47  * Ignores `locale' stuff.  Assumes that the upper and lower case
  48  * alphabets and digits are each contiguous.
  49  */
  50 unsigned long
  51 strtoul(nptr, endptr, base)
  52         const char *nptr;
  53         char **endptr;
  54         register int base;
  55 {
  56         register const char *s;
  57         register unsigned long acc, cutoff;
  58         register int c;
  59         register int neg, any, cutlim;
  60
  61         /*
  62          * See strtol for comments as to the logic used.
  63          */
  64         s = nptr;
  65         do {
  66                 c = (unsigned char) *s++;
  67         } while (isspace(c));
  68         if (c == '-') {
  69                 neg = 1;
  70                 c = *s++;
  71         } else {
  72                 neg = 0;
  73                 if (c == '+')
  74                         c = *s++;
  75         }
  76         if ((base == 0 || base == 16) &&
  77             c == '0' && (*s == 'x' || *s == 'X')) {
  78                 c = s[1];
  79                 s += 2;
  80                 base = 16;
  81         }
  82         if (base == 0)
  83                 base = c == '0' ? 8 : 10;
  84
  85         cutoff = ULONG_MAX / (unsigned long)base;
  86         cutlim = ULONG_MAX % (unsigned long)base;
  87         for (acc = 0, any = 0;; c = (unsigned char) *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)
  97                         continue;
  98                 if (acc > cutoff || acc == cutoff && c > cutlim) {
  99                         any = -1;
 100                         acc = ULONG_MAX;
 101                         errno = ERANGE;
 102                 } else {
 103                         any = 1;
 104                         acc *= (unsigned long)base;
 105                         acc += c;
 106                 }
 107         }
 108         if (neg && any > 0)
 109                 acc = -acc;
 110         if (endptr != 0)
 111                 *endptr = (char *) (any ? s - 1 : nptr);
 112         return (acc);
 113 }
 114 #endif /* !HAVE_STRTOUL */