src/system/libroot/posix/stdlib/strtol.c

   1 /*-
   2  * Copyright (c) 1990, 1993
   3  *      The Regents of the University of California.  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. All advertising materials mentioning features or use of this software
  14  *    must display the following acknowledgement:
  15  *      This product includes software developed by the University of
  16  *      California, Berkeley and its contributors.
  17  * 4. Neither the name of the University nor the names of its contributors
  18  *    may be used to endorse or promote products derived from this software
  19  *    without specific prior written permission.
  20  *
  21  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  31  * SUCH DAMAGE.
  32  */
  33
  34
  35 #include <limits.h>
  36 #include <ctype.h>
  37 #include <errno.h>
  38 #include <stdlib.h>
  39
  40 #include <errno_private.h>
  41
  42
  43 /*
  44  * Convert a string to a long integer.
  45  *
  46  * Assumes that the upper and lower case
  47  * alphabets and digits are each contiguous.
  48  */
  49
  50 long
  51 strtol(const char * __restrict nptr, char ** __restrict endptr, int base)
  52 {
  53         const char *s;
  54         unsigned long acc;
  55         char c;
  56         unsigned long cutoff;
  57         int neg, any, cutlim;
  58
  59         /*
  60          * Skip white space and pick up leading +/- sign if any.
  61          * If base is 0, allow 0x for hex and 0 for octal, else
  62          * assume decimal; if base is already 16, allow 0x.
  63          */
  64         s = nptr;
  65         do {
  66                 c = *s++;
  67         } while (isspace((unsigned char)c));
  68         if (c == '-') {
  69                 neg = 1;
  70                 c = *s++;
  71         } else {
  72                 neg = 0;
  73                 if (c == '+')
  74                         c = *s++;
  75         }
  76         if ((base == 0 || base == 16) &&
  77             c == '0' && (*s == 'x' || *s == 'X')) {
  78                 c = s[1];
  79                 s += 2;
  80                 base = 16;
  81         }
  82         if (base == 0)
  83                 base = c == '0' ? 8 : 10;
  84         acc = any = 0;
  85         if (base < 2 || base > 36)
  86                 goto noconv;
  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) + LONG_MAX
 106             : LONG_MAX;
 107         cutlim = cutoff % base;
 108         cutoff /= base;
 109         for ( ; ; c = *s++) {
 110                 if (c >= '0' && c <= '9')
 111                         c -= '0';
 112                 else if (c >= 'A' && c <= 'Z')
 113                         c -= 'A' - 10;
 114                 else if (c >= 'a' && c <= 'z')
 115                         c -= 'a' - 10;
 116                 else
 117                         break;
 118                 if (c >= base)
 119                         break;
 120                 if (any < 0 || acc > cutoff || (acc == cutoff && c > cutlim))
 121                         any = -1;
 122                 else {
 123                         any = 1;
 124                         acc *= base;
 125                         acc += c;
 126                 }
 127         }
 128         if (any < 0) {
 129                 acc = neg ? LONG_MIN : LONG_MAX;
 130                 __set_errno(ERANGE);
 131         } else if (!any) {
 132 noconv:
 133                 __set_errno(EINVAL);
 134         } else if (neg)
 135                 acc = -acc;
 136         if (endptr != NULL)
 137                 *endptr = (char *)(any ? s - 1 : nptr);
 138         return (acc);
 139 }
 140
 141
 142 long __strtol_internal(const char *number, char **_end, int base, int group);
 143
 144 long
 145 __strtol_internal(const char *number, char **_end, int base, int group)
 146 {
 147         // ToDo: group is currently not supported!
 148         (void)group;
 149
 150         return strtol(number, _end, base);
 151 }
 152