usr/src/boot/lib/libstand/strtoul.c

   1 /*
   2  * Copyright (c) 1990, 1993
   3  *      The Regents of the University of California.  All rights reserved.
   4  *
   5  * Copyright (c) 2011 The FreeBSD Foundation
   6  * All rights reserved.
   7  * Portions of this software were developed by David Chisnall
   8  * under sponsorship from the FreeBSD Foundation.
   9  *
  10  * Redistribution and use in source and binary forms, with or without
  11  * modification, are permitted provided that the following conditions
  12  * are met:
  13  * 1. Redistributions of source code must retain the above copyright
  14  *    notice, this list of conditions and the following disclaimer.
  15  * 2. Redistributions in binary form must reproduce the above copyright
  16  *    notice, this list of conditions and the following disclaimer in the
  17  *    documentation and/or other materials provided with the distribution.
  18  * 4. Neither the name of the University nor the names of its contributors
  19  *    may be used to endorse or promote products derived from this software
  20  *    without specific prior written permission.
  21  *
  22  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  23  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  24  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  25  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  26  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  27  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  28  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  29  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  30  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  31  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  32  * SUCH DAMAGE.
  33  */
  34
  35 #if defined(LIBC_SCCS) && !defined(lint)
  36 static char sccsid[] = "@(#)strtoul.c   8.1 (Berkeley) 6/4/93";
  37 #endif /* LIBC_SCCS and not lint */
  38 #include <sys/cdefs.h>
  39 __FBSDID("$FreeBSD$");
  40
  41 #include "stand.h"
  42 #include <limits.h>
  43
  44 /*
  45  * Convert a string to an unsigned long integer.
  46  *
  47  * Assumes that the upper and lower case
  48  * alphabets and digits are each contiguous.
  49  */
  50 unsigned long
  51 strtoul(const char * __restrict nptr, char ** __restrict endptr, int base)
  52 {
  53         const char *s;
  54         unsigned long acc;
  55         char c;
  56         unsigned long cutoff;
  57         int neg, any, cutlim;
  58
  59         /*
  60          * See strtol for comments as to the logic used.
  61          */
  62         s = nptr;
  63         do {
  64                 c = *s++;
  65         } while (isspace((unsigned char)c));
  66         if (c == '-') {
  67                 neg = 1;
  68                 c = *s++;
  69         } else {
  70                 neg = 0;
  71                 if (c == '+')
  72                         c = *s++;
  73         }
  74         if ((base == 0 || base == 16) &&
  75             c == '0' && (*s == 'x' || *s == 'X') &&
  76             ((s[1] >= '0' && s[1] <= '9') ||
  77             (s[1] >= 'A' && s[1] <= 'F') ||
  78             (s[1] >= 'a' && s[1] <= 'f'))) {
  79                 c = s[1];
  80                 s += 2;
  81                 base = 16;
  82         }
  83         if (base == 0)
  84                 base = c == '0' ? 8 : 10;
  85         acc = any = 0;
  86         if (base < 2 || base > 36)
  87                 goto noconv;
  88
  89         cutoff = ULONG_MAX / base;
  90         cutlim = ULONG_MAX % base;
  91         for ( ; ; c = *s++) {
  92                 if (c >= '0' && c <= '9')
  93                         c -= '0';
  94                 else if (c >= 'A' && c <= 'Z')
  95                         c -= 'A' - 10;
  96                 else if (c >= 'a' && c <= 'z')
  97                         c -= 'a' - 10;
  98                 else
  99                         break;
 100                 if (c >= base)
 101                         break;
 102                 if (any < 0 || acc > cutoff || (acc == cutoff && c > cutlim))
 103                         any = -1;
 104                 else {
 105                         any = 1;
 106                         acc *= base;
 107                         acc += c;
 108                 }
 109         }
 110         if (any < 0) {
 111                 acc = ULONG_MAX;
 112                 errno = ERANGE;
 113         } else if (!any) {
 114 noconv:
 115                 errno = EINVAL;
 116         } else if (neg)
 117                 acc = -acc;
 118         if (endptr != NULL)
 119                 *endptr = (char *)(any ? s - 1 : nptr);
 120         return (acc);
 121 }