libiberty/strtol.c

   1 /*-
   2  * Copyright (c) 1990 The 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 [rescinded 22 July 1999]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 /*
  32
  33 @deftypefn Supplemental {long int} strtol (const char *@var{string}, char **@var{endptr}, int @var{base})
  34
  35 The @code{strtol} function converts the string in @var{string} to a
  36 long integer value according to the given @var{base}, which must be
  37 between 2 and 36 inclusive, or be the special value 0.  If @var{base}
  38 is 0, @code{strtol} will look for the prefixes @code{0} and @code{0x}
  39 to indicate bases 8 and 16, respectively, else default to base 10.
  40 When the base is 16 (either explicitly or implicitly), a prefix of
  41 @code{0x} is allowed.  The handling of endptr is as that of
  42 @code{strtod} above.
  43
  44 @end deftypefn
  45
  46 */
  47
  48 #ifdef HAVE_CONFIG_H
  49 #include "config.h"
  50 #endif
  51 #ifdef HAVE_LIMITS_H
  52 #include <limits.h>
  53 #endif
  54 #ifdef HAVE_SYS_PARAM_H
  55 #include <sys/param.h>
  56 #endif
  57 #include <errno.h>
  58 #ifdef NEED_DECLARATION_ERRNO
  59 extern int errno;
  60 #endif
  61 #include "safe-ctype.h"
  62
  63 /* FIXME: It'd be nice to configure around these, but the include files are too
  64    painful.  These macros should at least be more portable than hardwired hex
  65    constants. */
  66
  67 #ifndef ULONG_MAX
  68 #define ULONG_MAX       ((unsigned long)(~0L))          /* 0xFFFFFFFF */
  69 #endif
  70
  71 #ifndef LONG_MAX
  72 #define LONG_MAX        ((long)(ULONG_MAX >> 1))        /* 0x7FFFFFFF */
  73 #endif
  74
  75 #ifndef LONG_MIN
  76 #define LONG_MIN        ((long)(~LONG_MAX))             /* 0x80000000 */
  77 #endif
  78
  79 /*
  80  * Convert a string to a long integer.
  81  *
  82  * Ignores `locale' stuff.  Assumes that the upper and lower case
  83  * alphabets and digits are each contiguous.
  84  */
  85 long
  86 strtol(nptr, endptr, base)
  87         const char *nptr;
  88         char **endptr;
  89         register int base;
  90 {
  91         register const char *s = nptr;
  92         register unsigned long acc;
  93         register int c;
  94         register unsigned long cutoff;
  95         register int neg = 0, any, cutlim;
  96
  97         /*
  98          * Skip white space and pick up leading +/- sign if any.
  99          * If base is 0, allow 0x for hex and 0 for octal, else
 100          * assume decimal; if base is already 16, allow 0x.
 101          */
 102         do {
 103                 c = *s++;
 104         } while (ISSPACE(c));
 105         if (c == '-') {
 106                 neg = 1;
 107                 c = *s++;
 108         } else if (c == '+')
 109                 c = *s++;
 110         if ((base == 0 || base == 16) &&
 111             c == '0' && (*s == 'x' || *s == 'X')) {
 112                 c = s[1];
 113                 s += 2;
 114                 base = 16;
 115         }
 116         if (base == 0)
 117                 base = c == '0' ? 8 : 10;
 118
 119         /*
 120          * Compute the cutoff value between legal numbers and illegal
 121          * numbers.  That is the largest legal value, divided by the
 122          * base.  An input number that is greater than this value, if
 123          * followed by a legal input character, is too big.  One that
 124          * is equal to this value may be valid or not; the limit
 125          * between valid and invalid numbers is then based on the last
 126          * digit.  For instance, if the range for longs is
 127          * [-2147483648..2147483647] and the input base is 10,
 128          * cutoff will be set to 214748364 and cutlim to either
 129          * 7 (neg==0) or 8 (neg==1), meaning that if we have accumulated
 130          * a value > 214748364, or equal but the next digit is > 7 (or 8),
 131          * the number is too big, and we will return a range error.
 132          *
 133          * Set any if any `digits' consumed; make it negative to indicate
 134          * overflow.
 135          */
 136         cutoff = neg ? -(unsigned long)LONG_MIN : LONG_MAX;
 137         cutlim = cutoff % (unsigned long)base;
 138         cutoff /= (unsigned long)base;
 139         for (acc = 0, any = 0;; c = *s++) {
 140                 if (ISDIGIT(c))
 141                         c -= '0';
 142                 else if (ISALPHA(c))
 143                         c -= ISUPPER(c) ? 'A' - 10 : 'a' - 10;
 144                 else
 145                         break;
 146                 if (c >= base)
 147                         break;
 148                 if (any < 0 || acc > cutoff || acc == cutoff && c > cutlim)
 149                         any = -1;
 150                 else {
 151                         any = 1;
 152                         acc *= base;
 153                         acc += c;
 154                 }
 155         }
 156         if (any < 0) {
 157                 acc = neg ? LONG_MIN : LONG_MAX;
 158                 errno = ERANGE;
 159         } else if (neg)
 160                 acc = -acc;
 161         if (endptr != 0)
 162                 *endptr = (char *) (any ? s - 1 : nptr);
 163         return (acc);
 164 }