dist/nvi/clib/strtol.c

   1 /*      $NetBSD$ */
   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. All advertising materials mentioning features or use of this software
  16  *    must display the following acknowledgement:
  17  *      This product includes software developed by the University of
  18  *      California, Berkeley and its contributors.
  19  * 4. Neither the name of the University nor the names of its contributors
  20  *    may be used to endorse or promote products derived from this software
  21  *    without specific prior written permission.
  22  *
  23  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  24  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  25  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  26  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  27  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  28  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  29  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  30  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  31  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  32  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  33  * SUCH DAMAGE.
  34  */
  35
  36 #include "config.h"
  37
  38 #if defined(LIBC_SCCS) && !defined(lint)
  39 static const char sccsid[] = "@(#)strtol.c      8.1 (Berkeley) 6/4/93";
  40 #endif /* LIBC_SCCS and not lint */
  41
  42 #include <limits.h>
  43 #include <ctype.h>
  44 #include <errno.h>
  45 #include <stdlib.h>
  46
  47 /*
  48  * Convert a string to a long integer.
  49  *
  50  * Ignores `locale' stuff.  Assumes that the upper and lower case
  51  * alphabets and digits are each contiguous.
  52  *
  53  * PUBLIC: #ifndef HAVE_STRTOL
  54  * PUBLIC: long strtol __P((const char *, char **, int));
  55  * PUBLIC: #endif
  56  */
  57 long
  58 strtol(const char *nptr, char **endptr, register int base)
  59 {
  60         register const char *s = nptr;
  61         register unsigned long acc;
  62         register int c;
  63         register unsigned long cutoff;
  64         register int neg = 0, any, cutlim;
  65
  66         /*
  67          * Skip white space and pick up leading +/- sign if any.
  68          * If base is 0, allow 0x for hex and 0 for octal, else
  69          * assume decimal; if base is already 16, allow 0x.
  70          */
  71         do {
  72                 c = *s++;
  73         } while (isspace(c));
  74         if (c == '-') {
  75                 neg = 1;
  76                 c = *s++;
  77         } else if (c == '+')
  78                 c = *s++;
  79         if ((base == 0 || base == 16) &&
  80             c == '0' && (*s == 'x' || *s == 'X')) {
  81                 c = s[1];
  82                 s += 2;
  83                 base = 16;
  84         }
  85         if (base == 0)
  86                 base = c == '0' ? 8 : 10;
  87
  88         /*
  89          * Compute the cutoff value between legal numbers and illegal
  90          * numbers.  That is the largest legal value, divided by the
  91          * base.  An input number that is greater than this value, if
  92          * followed by a legal input character, is too big.  One that
  93          * is equal to this value may be valid or not; the limit
  94          * between valid and invalid numbers is then based on the last
  95          * digit.  For instance, if the range for longs is
  96          * [-2147483648..2147483647] and the input base is 10,
  97          * cutoff will be set to 214748364 and cutlim to either
  98          * 7 (neg==0) or 8 (neg==1), meaning that if we have accumulated
  99          * a value > 214748364, or equal but the next digit is > 7 (or 8),
 100          * the number is too big, and we will return a range error.
 101          *
 102          * Set any if any `digits' consumed; make it negative to indicate
 103          * overflow.
 104          */
 105         cutoff = neg ? -(unsigned long)LONG_MIN : LONG_MAX;
 106         cutlim = cutoff % (unsigned long)base;
 107         cutoff /= (unsigned long)base;
 108         for (acc = 0, any = 0;; c = *s++) {
 109                 if (isdigit(c))
 110                         c -= '0';
 111                 else if (isalpha(c))
 112                         c -= isupper(c) ? 'A' - 10 : 'a' - 10;
 113                 else
 114                         break;
 115                 if (c >= base)
 116                         break;
 117                 if (any < 0 || acc > cutoff || acc == cutoff && c > cutlim)
 118                         any = -1;
 119                 else {
 120                         any = 1;
 121                         acc *= base;
 122                         acc += c;
 123                 }
 124         }
 125         if (any < 0) {
 126                 acc = neg ? LONG_MIN : LONG_MAX;
 127                 errno = ERANGE;
 128         } else if (neg)
 129                 acc = -acc;
 130         if (endptr != 0)
 131                 *endptr = (char *)(any ? s - 1 : nptr);
 132         return (acc);
 133 }