stdlib/strtol.c

   1 /* Copyright (C) 1991, 1992, 1994, 1995 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   int negative;
 116   register unsigned LONG int cutoff;
 117   register unsigned int cutlim;
 118   register unsigned LONG int i;
 119   register const char *s;
 120   register unsigned char c;
 121   const char *save, *end;
 122   int overflow;
 123
 124 #ifdef USE_NUMBER_GROUPING
 125   /* The thousands character of the current locale.  */
 126   wchar_t thousands;
 127   /* The numeric grouping specification of the current locale,
 128      in the format described in <locale.h>.  */
 129   const char *grouping;
 130
 131   if (group)
 132     {
 133       grouping = _NL_CURRENT (LC_NUMERIC, GROUPING);
 134       if (*grouping <= 0 || *grouping == CHAR_MAX)
 135         grouping = NULL;
 136       else
 137         {
 138           /* Figure out the thousands separator character.  */
 139           if (mbtowc (&thousands, _NL_CURRENT (LC_NUMERIC, THOUSANDS_SEP),
 140                       strlen (_NL_CURRENT (LC_NUMERIC, THOUSANDS_SEP))) <= 0)
 141             thousands = (wchar_t) *_NL_CURRENT (LC_NUMERIC, THOUSANDS_SEP);
 142           if (thousands == L'\0')
 143             grouping = NULL;
 144         }
 145     }
 146   else
 147     grouping = NULL;
 148 #endif
 149
 150   if (base < 0 || base == 1 || base > 36)
 151     base = 10;
 152
 153   save = s = nptr;
 154
 155   /* Skip white space.  */
 156   while (isspace (*s))
 157     ++s;
 158   if (*s == '\0')
 159     goto noconv;
 160
 161   /* Check for a sign.  */
 162   if (*s == '-')
 163     {
 164       negative = 1;
 165       ++s;
 166     }
 167   else if (*s == '+')
 168     {
 169       negative = 0;
 170       ++s;
 171     }
 172   else
 173     negative = 0;
 174
 175   if (base == 16 && s[0] == '0' && toupper (s[1]) == 'X')
 176     s += 2;
 177
 178   /* If BASE is zero, figure it out ourselves.  */
 179   if (base == 0)
 180     if (*s == '0')
 181       {
 182         if (toupper (s[1]) == 'X')
 183           {
 184             s += 2;
 185             base = 16;
 186           }
 187         else
 188           base = 8;
 189       }
 190     else
 191       base = 10;
 192
 193   /* Save the pointer so we can check later if anything happened.  */
 194   save = s;
 195
 196 #ifdef USE_NUMBER_GROUPING
 197   if (group)
 198     {
 199       /* Find the end of the digit string and check its grouping.  */
 200       end = s;
 201       for (c = *end; c != '\0'; c = *++end)
 202         if (c != thousands && !isdigit (c) &&
 203             (!isalpha (c) || toupper (c) - 'A' + 10 >= base))
 204           break;
 205       if (*s == thousands)
 206         end = s;
 207       else
 208         end = correctly_grouped_prefix (s, end, thousands, grouping);
 209     }
 210   else
 211 #endif
 212     end = NULL;
 213
 214   cutoff = ULONG_MAX / (unsigned LONG int) base;
 215   cutlim = ULONG_MAX % (unsigned LONG int) base;
 216
 217   overflow = 0;
 218   i = 0;
 219   for (c = *s; c != '\0'; c = *++s)
 220     {
 221       if (s == end)
 222         break;
 223       if (isdigit (c))
 224         c -= '0';
 225       else if (isalpha (c))
 226         c = toupper (c) - 'A' + 10;
 227       else
 228         break;
 229       if (c >= base)
 230         break;
 231       /* Check for overflow.  */
 232       if (i > cutoff || (i == cutoff && c > cutlim))
 233         overflow = 1;
 234       else
 235         {
 236           i *= (unsigned LONG int) base;
 237           i += c;
 238         }
 239     }
 240
 241   /* Check if anything actually happened.  */
 242   if (s == save)
 243     goto noconv;
 244
 245   /* Store in ENDPTR the address of one character
 246      past the last character we converted.  */
 247   if (endptr != NULL)
 248     *endptr = (char *) s;
 249
 250 #if !UNSIGNED
 251   /* Check for a value that is within the range of
 252      `unsigned LONG int', but outside the range of `LONG int'.  */
 253   if (i > (negative ?
 254            -(unsigned LONG int) LONG_MIN : (unsigned LONG int) LONG_MAX))
 255     overflow = 1;
 256 #endif
 257
 258   if (overflow)
 259     {
 260       errno = ERANGE;
 261 #if UNSIGNED
 262       return ULONG_MAX;
 263 #else
 264       return negative ? LONG_MIN : LONG_MAX;
 265 #endif
 266     }
 267
 268   /* Return the result of the appropriate sign.  */
 269   return (negative ? -i : i);
 270
 271 noconv:
 272   /* We must handle a special case here: the base is 0 or 16 and the
 273      first two characters and '0' and 'x', but the rest are no
 274      hexadecimal digits.  This is no error case.  We return 0 and
 275      ENDPTR points to the `x`.  */
 276   if (endptr != NULL)
 277     if (save - nptr >= 2 && tolower (save[-1]) == 'x' && save[-2] == '0')
 278       *endptr = (char *) &save[-1];
 279     else
 280       /*  There was no number to convert.  */
 281       *endptr = (char *) nptr;
 282
 283   return 0L;
 284 }
 285 \f
 286 /* External user entry point.  */
 287
 288 INT
 289 strtol (nptr, endptr, base)
 290      const char *nptr;
 291      char **endptr;
 292      int base;
 293 {
 294   return INTERNAL (strtol) (nptr, endptr, base, 0);
 295 }
 296
 297 #ifdef weak_symbol
 298 weak_symbol (strtol)
 299 #endif