src/tiff/port/strtoul.c

   1 /* $Id$ */
   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. 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 #if 0
  33 static char sccsid[] = "@(#)strtoul.c   8.1 (Berkeley) 6/4/93";
  34 __RCSID("$NetBSD: strtoul.c,v 1.16 2003/08/07 16:43:45 agc Exp $");
  35 #endif
  36
  37 #include <ctype.h>
  38 #include <errno.h>
  39 #include <limits.h>
  40 #include <stdlib.h>
  41
  42 /*
  43  * Convert a string to an unsigned long integer.
  44  *
  45  * Ignores `locale' stuff.  Assumes that the upper and lower case
  46  * alphabets and digits are each contiguous.
  47  */
  48 unsigned long
  49 strtoul(const char *nptr, char **endptr, int base)
  50 {
  51         const char *s;
  52         unsigned long acc, cutoff;
  53         int c;
  54         int neg, any, cutlim;
  55
  56         /*
  57          * See strtol for comments as to the logic used.
  58          */
  59         s = nptr;
  60         do {
  61                 c = (unsigned char) *s++;
  62         } while (isspace(c));
  63         if (c == '-') {
  64                 neg = 1;
  65                 c = *s++;
  66         } else {
  67                 neg = 0;
  68                 if (c == '+')
  69                         c = *s++;
  70         }
  71         if ((base == 0 || base == 16) &&
  72             c == '0' && (*s == 'x' || *s == 'X')) {
  73                 c = s[1];
  74                 s += 2;
  75                 base = 16;
  76         }
  77         if (base == 0)
  78                 base = c == '0' ? 8 : 10;
  79
  80         cutoff = ULONG_MAX / (unsigned long)base;
  81         cutlim = (int)(ULONG_MAX % (unsigned long)base);
  82         for (acc = 0, any = 0;; c = (unsigned char) *s++) {
  83                 if (isdigit(c))
  84                         c -= '0';
  85                 else if (isalpha(c))
  86                         c -= isupper(c) ? 'A' - 10 : 'a' - 10;
  87                 else
  88                         break;
  89                 if (c >= base)
  90                         break;
  91                 if (any < 0)
  92                         continue;
  93                 if (acc > cutoff || (acc == cutoff && c > cutlim)) {
  94                         any = -1;
  95                         acc = ULONG_MAX;
  96                         errno = ERANGE;
  97                 } else {
  98                         any = 1;
  99                         acc *= (unsigned long)base;
 100                         acc += c;
 101                 }
 102         }
 103         if (neg && any > 0)
 104                 acc = -acc;
 105         if (endptr != 0)
 106                 /* LINTED interface specification */
 107                 *endptr = (char *)(any ? s - 1 : nptr);
 108         return (acc);
 109 }