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 [rescinded 22 July 1999]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 #ifdef HAVE_CONFIG_H
  32 #include "config.h"
  33 #endif
  34 #ifdef HAVE_LIMITS_H
  35 #include <limits.h>
  36 #endif
  37 #ifdef HAVE_SYS_PARAM_H
  38 #include <sys/param.h>
  39 #endif
  40 #include <errno.h>
  41 #ifdef NEED_DECLARATION_ERRNO
  42 extern int errno;
  43 #endif
  44 #if 0
  45 #include <stdlib.h>
  46 #endif
  47 #include "ansidecl.h"
  48 #include "safe-ctype.h"
  49
  50 #ifndef ULONG_MAX
  51 #define ULONG_MAX       ((unsigned long)(~0L))          /* 0xFFFFFFFF */
  52 #endif
  53
  54 /*
  55  * Convert a string to an unsigned long integer.
  56  *
  57  * Ignores `locale' stuff.  Assumes that the upper and lower case
  58  * alphabets and digits are each contiguous.
  59  */
  60 unsigned long
  61 strtoul(const char *nptr, char **endptr, register int base)
  62 {
  63         register const char *s = nptr;
  64         register unsigned long acc;
  65         register int c;
  66         register unsigned long cutoff;
  67         register int neg = 0, any, cutlim;
  68
  69         /*
  70          * See strtol for comments as to the logic used.
  71          */
  72         do {
  73                 c = *s++;
  74         } while (ISSPACE(c));
  75         if (c == '-') {
  76                 neg = 1;
  77                 c = *s++;
  78         } else if (c == '+')
  79                 c = *s++;
  80         if ((base == 0 || base == 16) &&
  81             c == '0' && (*s == 'x' || *s == 'X')) {
  82                 c = s[1];
  83                 s += 2;
  84                 base = 16;
  85         }
  86         if (base == 0)
  87                 base = c == '0' ? 8 : 10;
  88         cutoff = (unsigned long)ULONG_MAX / (unsigned long)base;
  89         cutlim = (unsigned long)ULONG_MAX % (unsigned long)base;
  90         for (acc = 0, any = 0;; c = *s++) {
  91                 if (ISDIGIT(c))
  92                         c -= '0';
  93                 else if (ISALPHA(c))
  94                         c -= ISUPPER(c) ? 'A' - 10 : 'a' - 10;
  95                 else
  96                         break;
  97                 if (c >= base)
  98                         break;
  99                 if (any < 0 || acc > cutoff || (acc == cutoff && c > cutlim))
 100                         any = -1;
 101                 else {
 102                         any = 1;
 103                         acc *= base;
 104                         acc += c;
 105                 }
 106         }
 107         if (any < 0) {
 108                 acc = ULONG_MAX;
 109                 errno = ERANGE;
 110         } else if (neg)
 111                 acc = -acc;
 112         if (endptr != 0)
 113                 *endptr = (char *) (any ? s - 1 : nptr);
 114         return (acc);
 115 }