lib/sh/strtol.c

   1 /* strtol - Convert string representation of a number into an integer value.
   2    Copyright (C) 1997 Free Software Foundation, Inc.
   3
   4    This program is free software; you can redistribute it and/or modify it
   5    under the terms of the GNU General Public License as published by the
   6    Free Software Foundation; either version 2, or (at your option) any
   7    later version.
   8
   9    This program is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12    GNU General Public License for more details.
  13
  14    You should have received a copy of the GNU General Public License
  15    along with this program; if not, write to the Free Software Foundation,
  16    Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */
  17
  18 #include <config.h>
  19
  20 #if !defined (HAVE_STRTOL)
  21
  22 #include <ctype.h>
  23 #include <errno.h>
  24
  25 #ifndef errno
  26 extern int errno;
  27 #endif
  28
  29 #ifndef __set_errno
  30 #  define __set_errno(Val) errno = (Val)
  31 #endif
  32
  33 #ifdef HAVE_LIMITS_H
  34 #  include <limits.h>
  35 #endif
  36
  37 #include <stdc.h>
  38 #include <bashansi.h>
  39
  40 #ifndef NULL
  41 #  define NULL 0
  42 #endif
  43
  44 /* Nonzero if we are defining `strtoul', operating on unsigned integers.  */
  45 #ifndef UNSIGNED
  46 # define UNSIGNED 0
  47 # define RETTYPE long
  48 #else
  49 # define RETTYPE unsigned long
  50 #endif
  51
  52 /* Determine the name.  */
  53 #if UNSIGNED
  54 #  define strtol strtoul
  55 #endif
  56
  57 #ifndef CHAR_BIT
  58 #  define CHAR_BIT 8
  59 #endif
  60
  61 #ifndef ULONG_MAX
  62 #  define ULONG_MAX ((unsigned long) ~(unsigned long) 0)
  63 #  define ULONG_MIN ((unsigned long) 0 - ULONG_MAX)
  64 #endif
  65
  66 #ifndef LONG_MAX
  67 #  define LONG_MAX ((long) (ULONG_MAX >> 1))
  68 #  define LONG_MIN ((long) (0 - LONG_MAX))
  69 #endif
  70
  71 /* Convert NPTR to an `unsigned long int' or `long int' in base BASE.
  72    If BASE is 0 the base is determined by the presence of a leading
  73    zero, indicating octal or a leading "0x" or "0X", indicating hexadecimal.
  74    If BASE is < 2 or > 36, it is reset to 10.
  75    If ENDPTR is not NULL, a pointer to the character after the last
  76    one converted is stored in *ENDPTR.  */
  77
  78 RETTYPE
  79 strtol (nptr, endptr, base)
  80      const char *nptr;
  81      char **endptr;
  82      int base;
  83 {
  84   int negative;
  85   register unsigned long cutoff, i;
  86   register unsigned int cutlim;
  87   register const char *s;
  88   register unsigned char c;
  89   const char *save, *end;
  90   int overflow;
  91
  92   if (base < 0 || base == 1 || base > 36)
  93     base = 10;
  94
  95   save = s = nptr;
  96
  97   /* Skip white space.  */
  98   while (isspace (*s))
  99     ++s;
 100   if (*s == '\0')
 101     goto noconv;
 102
 103   /* Check for a sign.  */
 104   if (*s == '-' || *s == '+')
 105     {
 106       negative = (*s == '-');
 107       ++s;
 108     }
 109   else
 110     negative = 0;
 111
 112   if (base == 16 && *s == '0' && toupper (s[1]) == 'X')
 113     s += 2;
 114
 115   /* If BASE is zero, figure it out ourselves.  */
 116   if (base == 0)
 117     if (*s == '0')
 118       {
 119         if (toupper (s[1]) == 'X')
 120           {
 121             s += 2;
 122             base = 16;
 123           }
 124         else
 125           base = 8;
 126       }
 127     else
 128       base = 10;
 129
 130   /* Save the pointer so we can check later if anything happened.  */
 131   save = s;
 132
 133   end = NULL;
 134
 135   cutoff = ULONG_MAX / (unsigned long int) base;
 136   cutlim = ULONG_MAX % (unsigned long int) base;
 137
 138   overflow = 0;
 139   i = 0;
 140   for (c = *s; c != '\0'; c = *++s)
 141     {
 142       if (s == end)
 143         break;
 144
 145       if (c >= '0' && c <= '9')
 146         c -= '0';
 147       else if (isalpha (c))
 148         c = toupper (c) - 'A' + 10;
 149       else
 150         break;
 151
 152       if ((int) c >= base)
 153         break;
 154
 155       /* Check for overflow.  */
 156       if (i > cutoff || (i == cutoff && c > cutlim))
 157         overflow = 1;
 158       else
 159         {
 160           i *= (unsigned long int) base;
 161           i += c;
 162         }
 163     }
 164
 165   /* Check if anything actually happened.  */
 166   if (s == save)
 167     goto noconv;
 168
 169   /* Store in ENDPTR the address of one character
 170      past the last character we converted.  */
 171   if (endptr != NULL)
 172     *endptr = (char *) s;
 173
 174 #if !UNSIGNED
 175   /* Check for a value that is within the range of
 176      `unsigned long int', but outside the range of `long int'.  */
 177   if (overflow == 0
 178       && i > (negative
 179               ? -((unsigned long) (LONG_MIN + 1)) + 1
 180               : (unsigned long) LONG_MAX))
 181     overflow = 1;
 182 #endif
 183
 184   if (overflow)
 185     {
 186       __set_errno (ERANGE);
 187 #if UNSIGNED
 188       return ULONG_MAX;
 189 #else
 190       return negative ? LONG_MIN : LONG_MAX;
 191 #endif
 192     }
 193
 194   /* Return the result with the appropriate sign.  */
 195   return (negative ? -i : i);
 196
 197 noconv:
 198   /* We must handle a special case here: the base is 0 or 16 and the
 199      first two characters are '0' and 'x', but the rest are no
 200      hexadecimal digits.  This is no error case.  We return 0 and
 201      ENDPTR points to the `x'.  */
 202   if (endptr != NULL)
 203     {
 204       if (save - nptr >= 2 && toupper (save[-1]) == 'X' && save[-2] == '0')
 205         *endptr = (char *) &save[-1];
 206       else
 207         /*  There was no number to convert.  */
 208         *endptr = (char *) nptr;
 209     }
 210
 211   return 0L;
 212 }
 213
 214 #endif /* !HAVE_STRTOL */