stdlib/strtol.c

   1 /* Copyright (C) 1991, 1992, 1994, 1995, 1996 Free Software Foundation, Inc.
   2
   3 This file is part of the GNU C Library.
   4
   5 The GNU C Library is free software; you can redistribute it and/or
   6 modify it under the terms of the GNU Library General Public License as
   7 published by the Free Software Foundation; either version 2 of the
   8 License, or (at your option) any later version.
   9
  10 The GNU C Library is distributed in the hope that it will be useful,
  11 but WITHOUT ANY WARRANTY; without even the implied warranty of
  12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13 Library General Public License for more details.
  14
  15 You should have received a copy of the GNU Library General Public
  16 License along with the GNU C Library; see the file COPYING.LIB.  If
  17 not, write to the Free Software Foundation, Inc., 675 Mass Ave,
  18 Cambridge, MA 02139, USA.  */
  19
  20 #ifdef HAVE_CONFIG_H
  21 # include <config.h>
  22 #endif
  23
  24 #ifdef _LIBC
  25 # define USE_NUMBER_GROUPING
  26 # define STDC_HEADERS
  27 # define HAVE_LIMITS_H
  28 #endif
  29
  30 #include <ctype.h>
  31 #include <errno.h>
  32 #ifndef errno
  33 extern int errno;
  34 #endif
  35
  36 #ifdef HAVE_LIMITS_H
  37 # include <limits.h>
  38 #endif
  39
  40 #ifdef STDC_HEADERS
  41 # include <stddef.h>
  42 # include <stdlib.h>
  43 #else
  44 # ifndef NULL
  45 #  define NULL 0
  46 # endif
  47 #endif
  48
  49 #ifdef USE_NUMBER_GROUPING
  50 # include "../locale/localeinfo.h"
  51 #endif
  52
  53 /* Nonzero if we are defining `strtoul' or `strtouq', operating on
  54    unsigned integers.  */
  55 #ifndef UNSIGNED
  56 # define UNSIGNED 0
  57 # define INT LONG int
  58 #else
  59 # define strtol strtoul
  60 # define INT unsigned LONG int
  61 #endif
  62
  63 /* If QUAD is defined, we are defining `strtoq' or `strtouq',
  64    operating on `long long int's.  */
  65 #ifdef QUAD
  66 # if UNSIGNED
  67 #  define strtoul strtouq
  68 # else
  69 #  define strtol strtoq
  70 # endif
  71 # define LONG long long
  72 # undef LONG_MIN
  73 # define LONG_MIN LONG_LONG_MIN
  74 # undef LONG_MAX
  75 # define LONG_MAX LONG_LONG_MAX
  76 # undef ULONG_MAX
  77 # define ULONG_MAX ULONG_LONG_MAX
  78 # if __GNUC__ == 2 && __GNUC_MINOR__ < 7
  79    /* Work around gcc bug with using this constant.  */
  80    static const unsigned long long int maxquad = ULONG_LONG_MAX;
  81 #  undef ULONG_MAX
  82 #  define ULONG_MAX maxquad
  83 # endif
  84 #else
  85 # define LONG long
  86 #endif
  87
  88 #ifdef __STDC__
  89 # define INTERNAL(x) INTERNAL1(x)
  90 # define INTERNAL1(x) __##x##_internal
  91 #else
  92 # define INTERNAL(x) __/**/x/**/_internal
  93 #endif
  94
  95 #ifdef USE_NUMBER_GROUPING
  96 /* This file defines a function to check for correct grouping.  */
  97 # include "grouping.h"
  98 #endif
  99
 100
 101 /* Convert NPTR to an `unsigned long int' or `long int' in base BASE.
 102    If BASE is 0 the base is determined by the presence of a leading
 103    zero, indicating octal or a leading "0x" or "0X", indicating hexadecimal.
 104    If BASE is < 2 or > 36, it is reset to 10.
 105    If ENDPTR is not NULL, a pointer to the character after the last
 106    one converted is stored in *ENDPTR.  */
 107
 108 INT
 109 INTERNAL (strtol) (nptr, endptr, base, group)
 110      const char *nptr;
 111      char **endptr;
 112      int base;
 113      int group;
 114 {
 115 #if UNSIGNED
 116 #define negative 0
 117 #else
 118   int negative;
 119 #endif
 120   register unsigned LONG int cutoff;
 121   register unsigned int cutlim;
 122   register unsigned LONG int i;
 123   register const char *s;
 124   register unsigned char c;
 125   const char *save, *end;
 126   int overflow;
 127
 128 #ifdef USE_NUMBER_GROUPING
 129   /* The thousands character of the current locale.  */
 130   wchar_t thousands;
 131   /* The numeric grouping specification of the current locale,
 132      in the format described in <locale.h>.  */
 133   const char *grouping;
 134
 135   if (group)
 136     {
 137       grouping = _NL_CURRENT (LC_NUMERIC, GROUPING);
 138       if (*grouping <= 0 || *grouping == CHAR_MAX)
 139         grouping = NULL;
 140       else
 141         {
 142           /* Figure out the thousands separator character.  */
 143           if (mbtowc (&thousands, _NL_CURRENT (LC_NUMERIC, THOUSANDS_SEP),
 144                       strlen (_NL_CURRENT (LC_NUMERIC, THOUSANDS_SEP))) <= 0)
 145             thousands = (wchar_t) *_NL_CURRENT (LC_NUMERIC, THOUSANDS_SEP);
 146           if (thousands == L'\0')
 147             grouping = NULL;
 148         }
 149     }
 150   else
 151     grouping = NULL;
 152 #endif
 153
 154   if (base < 0 || base == 1 || base > 36)
 155     base = 10;
 156
 157   save = s = nptr;
 158
 159   /* Skip white space.  */
 160   while (isspace (*s))
 161     ++s;
 162   if (*s == '\0')
 163     goto noconv;
 164
 165 #if !UNSIGNED
 166   /* Check for a sign.  */
 167   if (*s == '-')
 168     {
 169       negative = 1;
 170       ++s;
 171     }
 172   else if (*s == '+')
 173     {
 174       negative = 0;
 175       ++s;
 176     }
 177   else
 178     negative = 0;
 179 #endif
 180
 181   if (base == 16 && s[0] == '0' && toupper (s[1]) == 'X')
 182     s += 2;
 183
 184   /* If BASE is zero, figure it out ourselves.  */
 185   if (base == 0)
 186     if (*s == '0')
 187       {
 188         if (toupper (s[1]) == 'X')
 189           {
 190             s += 2;
 191             base = 16;
 192           }
 193         else
 194           base = 8;
 195       }
 196     else
 197       base = 10;
 198
 199   /* Save the pointer so we can check later if anything happened.  */
 200   save = s;
 201
 202 #ifdef USE_NUMBER_GROUPING
 203   if (group)
 204     {
 205       /* Find the end of the digit string and check its grouping.  */
 206       end = s;
 207       for (c = *end; c != '\0'; c = *++end)
 208         if (c != thousands && !isdigit (c) &&
 209             (!isalpha (c) || toupper (c) - 'A' + 10 >= base))
 210           break;
 211       if (*s == thousands)
 212         end = s;
 213       else
 214         end = correctly_grouped_prefix (s, end, thousands, grouping);
 215     }
 216   else
 217 #endif
 218     end = NULL;
 219
 220   cutoff = ULONG_MAX / (unsigned LONG int) base;
 221   cutlim = ULONG_MAX % (unsigned LONG int) base;
 222
 223   overflow = 0;
 224   i = 0;
 225   for (c = *s; c != '\0'; c = *++s)
 226     {
 227       if (s == end)
 228         break;
 229       if (isdigit (c))
 230         c -= '0';
 231       else if (isalpha (c))
 232         c = toupper (c) - 'A' + 10;
 233       else
 234         break;
 235       if (c >= base)
 236         break;
 237       /* Check for overflow.  */
 238       if (i > cutoff || (i == cutoff && c > cutlim))
 239         overflow = 1;
 240       else
 241         {
 242           i *= (unsigned LONG int) base;
 243           i += c;
 244         }
 245     }
 246
 247   /* Check if anything actually happened.  */
 248   if (s == save)
 249     goto noconv;
 250
 251   /* Store in ENDPTR the address of one character
 252      past the last character we converted.  */
 253   if (endptr != NULL)
 254     *endptr = (char *) s;
 255
 256 #if !UNSIGNED
 257   /* Check for a value that is within the range of
 258      `unsigned LONG int', but outside the range of `LONG int'.  */
 259   if (i > (negative ?
 260            -(unsigned LONG int) LONG_MIN : (unsigned LONG int) LONG_MAX))
 261     overflow = 1;
 262 #endif
 263
 264   if (overflow)
 265     {
 266       errno = ERANGE;
 267 #if UNSIGNED
 268       return ULONG_MAX;
 269 #else
 270       return negative ? LONG_MIN : LONG_MAX;
 271 #endif
 272     }
 273
 274   /* Return the result of the appropriate sign.  */
 275   return (negative ? -i : i);
 276
 277 noconv:
 278   /* We must handle a special case here: the base is 0 or 16 and the
 279      first two characters and '0' and 'x', but the rest are no
 280      hexadecimal digits.  This is no error case.  We return 0 and
 281      ENDPTR points to the `x`.  */
 282   if (endptr != NULL)
 283     if (save - nptr >= 2 && tolower (save[-1]) == 'x' && save[-2] == '0')
 284       *endptr = (char *) &save[-1];
 285     else
 286       /*  There was no number to convert.  */
 287       *endptr = (char *) nptr;
 288
 289   return 0L;
 290 }
 291 \f
 292 /* External user entry point.  */
 293
 294 INT
 295 strtol (nptr, endptr, base)
 296      const char *nptr;
 297      char **endptr;
 298      int base;
 299 {
 300   return INTERNAL (strtol) (nptr, endptr, base, 0);
 301 }
 302
 303 #ifdef weak_symbol
 304 weak_symbol (strtol)
 305 #endif