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 [rescinded 22 July 1999]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}, @
  34   char **@var{endptr}, int @var{base})
  35 @deftypefnx Supplemental {unsigned long int} strtoul (const char *@var{string}, @
  36   char **@var{endptr}, int @var{base})
  37
  38 The @code{strtol} function converts the string in @var{string} to a
  39 long integer value according to the given @var{base}, which must be
  40 between 2 and 36 inclusive, or be the special value 0.  If @var{base}
  41 is 0, @code{strtol} will look for the prefixes @code{0} and @code{0x}
  42 to indicate bases 8 and 16, respectively, else default to base 10.
  43 When the base is 16 (either explicitly or implicitly), a prefix of
  44 @code{0x} is allowed.  The handling of @var{endptr} is as that of
  45 @code{strtod} above.  The @code{strtoul} function is the same, except
  46 that the converted value is unsigned.
  47
  48 @end deftypefn
  49
  50 */
  51
  52 #ifdef HAVE_CONFIG_H
  53 #include "config.h"
  54 #endif
  55 #ifdef HAVE_LIMITS_H
  56 #include <limits.h>
  57 #endif
  58 #ifdef HAVE_SYS_PARAM_H
  59 #include <sys/param.h>
  60 #endif
  61 #include <errno.h>
  62 #ifdef NEED_DECLARATION_ERRNO
  63 extern int errno;
  64 #endif
  65 #include "safe-ctype.h"
  66
  67 /* FIXME: It'd be nice to configure around these, but the include files are too
  68    painful.  These macros should at least be more portable than hardwired hex
  69    constants. */
  70
  71 #ifndef ULONG_MAX
  72 #define ULONG_MAX       ((unsigned long)(~0L))          /* 0xFFFFFFFF */
  73 #endif
  74
  75 #ifndef LONG_MAX
  76 #define LONG_MAX        ((long)(ULONG_MAX >> 1))        /* 0x7FFFFFFF */
  77 #endif
  78
  79 #ifndef LONG_MIN
  80 #define LONG_MIN        ((long)(~LONG_MAX))             /* 0x80000000 */
  81 #endif
  82
  83 /*
  84  * Convert a string to a long integer.
  85  *
  86  * Ignores `locale' stuff.  Assumes that the upper and lower case
  87  * alphabets and digits are each contiguous.
  88  */
  89 long
  90 strtol(const char *nptr, char **endptr, register int base)
  91 {
  92         register const char *s = nptr;
  93         register unsigned long acc;
  94         register int c;
  95         register unsigned long cutoff;
  96         register int neg = 0, any, cutlim;
  97
  98         /*
  99          * Skip white space and pick up leading +/- sign if any.
 100          * If base is 0, allow 0x for hex and 0 for octal, else
 101          * assume decimal; if base is already 16, allow 0x.
 102          */
 103         do {
 104                 c = *s++;
 105         } while (ISSPACE(c));
 106         if (c == '-') {
 107                 neg = 1;
 108                 c = *s++;
 109         } else if (c == '+')
 110                 c = *s++;
 111         if ((base == 0 || base == 16) &&
 112             c == '0' && (*s == 'x' || *s == 'X')) {
 113                 c = s[1];
 114                 s += 2;
 115                 base = 16;
 116         }
 117         if (base == 0)
 118                 base = c == '0' ? 8 : 10;
 119
 120         /*
 121          * Compute the cutoff value between legal numbers and illegal
 122          * numbers.  That is the largest legal value, divided by the
 123          * base.  An input number that is greater than this value, if
 124          * followed by a legal input character, is too big.  One that
 125          * is equal to this value may be valid or not; the limit
 126          * between valid and invalid numbers is then based on the last
 127          * digit.  For instance, if the range for longs is
 128          * [-2147483648..2147483647] and the input base is 10,
 129          * cutoff will be set to 214748364 and cutlim to either
 130          * 7 (neg==0) or 8 (neg==1), meaning that if we have accumulated
 131          * a value > 214748364, or equal but the next digit is > 7 (or 8),
 132          * the number is too big, and we will return a range error.
 133          *
 134          * Set any if any `digits' consumed; make it negative to indicate
 135          * overflow.
 136          */
 137         cutoff = neg ? -(unsigned long)LONG_MIN : LONG_MAX;
 138         cutlim = cutoff % (unsigned long)base;
 139         cutoff /= (unsigned long)base;
 140         for (acc = 0, any = 0;; c = *s++) {
 141                 if (ISDIGIT(c))
 142                         c -= '0';
 143                 else if (ISALPHA(c))
 144                         c -= ISUPPER(c) ? 'A' - 10 : 'a' - 10;
 145                 else
 146                         break;
 147                 if (c >= base)
 148                         break;
 149                 if (any < 0 || acc > cutoff || (acc == cutoff && c > cutlim))
 150                         any = -1;
 151                 else {
 152                         any = 1;
 153                         acc *= base;
 154                         acc += c;
 155                 }
 156         }
 157         if (any < 0) {
 158                 acc = neg ? LONG_MIN : LONG_MAX;
 159                 errno = ERANGE;
 160         } else if (neg)
 161                 acc = -acc;
 162         if (endptr != 0)
 163                 *endptr = (char *) (any ? s - 1 : nptr);
 164         return (acc);
 165 }