stdlib/strtoul.c

   1 /*
   2  * Copyright (c) 1999 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * Copyright (c) 1999-2003 Apple Computer, Inc.  All Rights Reserved.
   7  *
   8  * This file contains Original Code and/or Modifications of Original Code
   9  * as defined in and that are subject to the Apple Public Source License
  10  * Version 2.0 (the 'License'). You may not use this file except in
  11  * compliance with the License. Please obtain a copy of the License at
  12  * http://www.opensource.apple.com/apsl/ and read it before using this
  13  * file.
  14  *
  15  * The Original Code and all software distributed under the License are
  16  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  17  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  18  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  19  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  20  * Please see the License for the specific language governing rights and
  21  * limitations under the License.
  22  *
  23  * @APPLE_LICENSE_HEADER_END@
  24  */
  25 /*
  26  * Copyright (c) 1990, 1993
  27  *      The Regents of the University of California.  All rights reserved.
  28  *
  29  * Redistribution and use in source and binary forms, with or without
  30  * modification, are permitted provided that the following conditions
  31  * are met:
  32  * 1. Redistributions of source code must retain the above copyright
  33  *    notice, this list of conditions and the following disclaimer.
  34  * 2. Redistributions in binary form must reproduce the above copyright
  35  *    notice, this list of conditions and the following disclaimer in the
  36  *    documentation and/or other materials provided with the distribution.
  37  * 3. All advertising materials mentioning features or use of this software
  38  *    must display the following acknowledgement:
  39  *      This product includes software developed by the University of
  40  *      California, Berkeley and its contributors.
  41  * 4. Neither the name of the University nor the names of its contributors
  42  *    may be used to endorse or promote products derived from this software
  43  *    without specific prior written permission.
  44  *
  45  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  46  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  47  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  48  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  49  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  50  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  51  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  52  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  53  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  54  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  55  * SUCH DAMAGE.
  56  */
  57
  58
  59 #include <limits.h>
  60 #include <ctype.h>
  61 #include <errno.h>
  62 #include <stdlib.h>
  63
  64 /*
  65  * Convert a string to an unsigned long integer.
  66  *
  67  * Ignores `locale' stuff.  Assumes that the upper and lower case
  68  * alphabets and digits are each contiguous.
  69  */
  70 unsigned long
  71 strtoul(nptr, endptr, base)
  72         const char *nptr;
  73         char **endptr;
  74         register int base;
  75 {
  76         register const char *s = nptr;
  77         register unsigned long acc;
  78         register int c;
  79         register unsigned long cutoff;
  80         register int neg = 0, any, cutlim;
  81
  82         /*
  83          * See strtol for comments as to the logic used.
  84          */
  85         do {
  86                 c = *s++;
  87         } while (isspace(c));
  88         if (c == '-') {
  89                 neg = 1;
  90                 c = *s++;
  91         } else if (c == '+')
  92                 c = *s++;
  93         if ((base == 0 || base == 16) &&
  94             c == '0' && (*s == 'x' || *s == 'X')) {
  95                 c = s[1];
  96                 s += 2;
  97                 base = 16;
  98         }
  99         if (base == 0)
 100                 base = c == '0' ? 8 : 10;
 101         cutoff = (unsigned long)ULONG_MAX / (unsigned long)base;
 102         cutlim = (unsigned long)ULONG_MAX % (unsigned long)base;
 103         for (acc = 0, any = 0;; c = *s++) {
 104                 if (isdigit(c))
 105                         c -= '0';
 106                 else if (isalpha(c))
 107                         c -= isupper(c) ? 'A' - 10 : 'a' - 10;
 108                 else
 109                         break;
 110                 if (c >= base)
 111                         break;
 112                 if (any < 0 || acc > cutoff || acc == cutoff && c > cutlim)
 113                         any = -1;
 114                 else {
 115                         any = 1;
 116                         acc *= base;
 117                         acc += c;
 118                 }
 119         }
 120         if (any < 0) {
 121                 acc = ULONG_MAX;
 122                 errno = ERANGE;
 123         } else if (neg)
 124                 acc = -acc;
 125         if (endptr != 0)
 126                 *endptr = (char *)(any ? s - 1 : nptr);
 127         return (acc);
 128 }