libiberty/strtoul.c

   1 /*
   2  * Copyright (c) 1990 Regents of the University of California.
   3  * All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  * 3. [rescinded 22 July 1999]
  14  * 4. Neither the name of the University nor the names of its contributors
  15  *    may be used to endorse or promote products derived from this software
  16  *    without specific prior written permission.
  17  *
  18  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  19  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  20  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  21  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  22  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  23  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  24  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  25  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  26  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  27  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  28  * SUCH DAMAGE.
  29  */
  30
  31 #include <limits.h>
  32 #include <ctype.h>
  33 #include <errno.h>
  34 #if 0
  35 #include <stdlib.h>
  36 #endif
  37 #include "ansidecl.h"
  38
  39 #ifndef ULONG_MAX
  40 #define ULONG_MAX       ((unsigned long)(~0L))          /* 0xFFFFFFFF */
  41 #endif
  42
  43 /*
  44  * Convert a string to an unsigned long integer.
  45  *
  46  * Ignores `locale' stuff.  Assumes that the upper and lower case
  47  * alphabets and digits are each contiguous.
  48  */
  49 unsigned long
  50 strtoul(nptr, endptr, base)
  51         const char *nptr;
  52         char **endptr;
  53         register int base;
  54 {
  55         register const char *s = nptr;
  56         register unsigned long acc;
  57         register int c;
  58         register unsigned long cutoff;
  59         register int neg = 0, any, cutlim;
  60
  61         /*
  62          * See strtol for comments as to the logic used.
  63          */
  64         do {
  65                 c = *s++;
  66         } while (isspace(c));
  67         if (c == '-') {
  68                 neg = 1;
  69                 c = *s++;
  70         } else if (c == '+')
  71                 c = *s++;
  72         if ((base == 0 || base == 16) &&
  73             c == '0' && (*s == 'x' || *s == 'X')) {
  74                 c = s[1];
  75                 s += 2;
  76                 base = 16;
  77         }
  78         if (base == 0)
  79                 base = c == '0' ? 8 : 10;
  80         cutoff = (unsigned long)ULONG_MAX / (unsigned long)base;
  81         cutlim = (unsigned long)ULONG_MAX % (unsigned long)base;
  82         for (acc = 0, any = 0;; c = *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 || acc > cutoff || (acc == cutoff && c > cutlim))
  92                         any = -1;
  93                 else {
  94                         any = 1;
  95                         acc *= base;
  96                         acc += c;
  97                 }
  98         }
  99         if (any < 0) {
 100                 acc = ULONG_MAX;
 101                 errno = ERANGE;
 102         } else if (neg)
 103                 acc = -acc;
 104         if (endptr != 0)
 105                 *endptr = (char *) (any ? s - 1 : nptr);
 106         return (acc);
 107 }