newlib/libc/stdlib/strtol.c

   1 /*
   2 FUNCTION
   3    <<strtol>>, <<strtol_l>>---string to long
   4
   5 INDEX
   6         strtol
   7
   8 INDEX
   9         strtol_l
  10
  11 INDEX
  12         _strtol_r
  13
  14 SYNOPSIS
  15         #include <stdlib.h>
  16         long strtol(const char *restrict <[s]>, char **restrict <[ptr]>,
  17                     int <[base]>);
  18
  19         #include <stdlib.h>
  20         long strtol_l(const char *restrict <[s]>, char **restrict <[ptr]>,
  21                       int <[base]>, locale_t <[locale]>);
  22
  23         long _strtol_r(void *<[reent]>, const char *restrict <[s]>,
  24                        char **restrict <[ptr]>,int <[base]>);
  25
  26 DESCRIPTION
  27 The function <<strtol>> converts the string <<*<[s]>>> to
  28 a <<long>>. First, it breaks down the string into three parts:
  29 leading whitespace, which is ignored; a subject string consisting
  30 of characters resembling an integer in the radix specified by <[base]>;
  31 and a trailing portion consisting of zero or more unparseable characters,
  32 and always including the terminating null character. Then, it attempts
  33 to convert the subject string into a <<long>> and returns the
  34 result.
  35
  36 If the value of <[base]> is 0, the subject string is expected to look
  37 like a normal C integer constant: an optional sign, a possible `<<0x>>'
  38 indicating a hexadecimal base, and a number. If <[base]> is between
  39 2 and 36, the expected form of the subject is a sequence of letters
  40 and digits representing an integer in the radix specified by <[base]>,
  41 with an optional plus or minus sign. The letters <<a>>--<<z>> (or,
  42 equivalently, <<A>>--<<Z>>) are used to signify values from 10 to 35;
  43 only letters whose ascribed values are less than <[base]> are
  44 permitted. If <[base]> is 16, a leading <<0x>> is permitted.
  45
  46 The subject sequence is the longest initial sequence of the input
  47 string that has the expected form, starting with the first
  48 non-whitespace character.  If the string is empty or consists entirely
  49 of whitespace, or if the first non-whitespace character is not a
  50 permissible letter or digit, the subject string is empty.
  51
  52 If the subject string is acceptable, and the value of <[base]> is zero,
  53 <<strtol>> attempts to determine the radix from the input string. A
  54 string with a leading <<0x>> is treated as a hexadecimal value; a string with
  55 a leading 0 and no <<x>> is treated as octal; all other strings are
  56 treated as decimal. If <[base]> is between 2 and 36, it is used as the
  57 conversion radix, as described above. If the subject string begins with
  58 a minus sign, the value is negated. Finally, a pointer to the first
  59 character past the converted subject string is stored in <[ptr]>, if
  60 <[ptr]> is not <<NULL>>.
  61
  62 If the subject string is empty (or not in acceptable form), no conversion
  63 is performed and the value of <[s]> is stored in <[ptr]> (if <[ptr]> is
  64 not <<NULL>>).
  65
  66 <<strtol_l>> is like <<strtol>> but performs the conversion based on the
  67 locale specified by the locale object locale.  If <[locale]> is
  68 LC_GLOBAL_LOCALE or not a valid locale object, the behaviour is undefined.
  69
  70 The alternate function <<_strtol_r>> is a reentrant version.  The
  71 extra argument <[reent]> is a pointer to a reentrancy structure.
  72
  73 RETURNS
  74 <<strtol>>, <<strtol_l>> return the converted value, if any. If no
  75 conversion was made, 0 is returned.
  76
  77 <<strtol>>, <<strtol_l>> return <<LONG_MAX>> or <<LONG_MIN>> if the
  78 magnitude of the converted value is too large, and sets <<errno>>
  79 to <<ERANGE>>.
  80
  81 PORTABILITY
  82 <<strtol>> is ANSI.
  83 <<strtol_l>> is a GNU extension.
  84
  85 No supporting OS subroutines are required.
  86 */
  87
  88 /*-
  89  * Copyright (c) 1990 The Regents of the University of California.
  90  * All rights reserved.
  91  *
  92  * Redistribution and use in source and binary forms, with or without
  93  * modification, are permitted provided that the following conditions
  94  * are met:
  95  * 1. Redistributions of source code must retain the above copyright
  96  *    notice, this list of conditions and the following disclaimer.
  97  * 2. Redistributions in binary form must reproduce the above copyright
  98  *    notice, this list of conditions and the following disclaimer in the
  99  *    documentation and/or other materials provided with the distribution.
 100  * 3. Neither the name of the University nor the names of its contributors
 101  *    may be used to endorse or promote products derived from this software
 102  *    without specific prior written permission.
 103  *
 104  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 105  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 106  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 107  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 108  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 109  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 110  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 111  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 112  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 113  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 114  * SUCH DAMAGE.
 115  */
 116
 117 #define _GNU_SOURCE
 118 #include <_ansi.h>
 119 #include <limits.h>
 120 #include <ctype.h>
 121 #include <errno.h>
 122 #include <stdlib.h>
 123 #include <reent.h>
 124 #include "../locale/setlocale.h"
 125
 126 /*
 127  * Convert a string to a long integer.
 128  */
 129 static long
 130 _strtol_l (struct _reent *rptr, const char *__restrict nptr,
 131            char **__restrict endptr, int base, locale_t loc)
 132 {
 133         register const unsigned char *s = (const unsigned char *)nptr;
 134         register unsigned long acc;
 135         register int c;
 136         register unsigned long cutoff;
 137         register int neg = 0, any, cutlim;
 138
 139         if (base < 0 || base == 1 || base > 36) {
 140                 errno = EINVAL;
 141                 return 0;
 142         }
 143
 144         /*
 145          * Skip white space and pick up leading +/- sign if any.
 146          * If base is 0, allow 0x for hex and 0 for octal, else
 147          * assume decimal; if base is already 16, allow 0x.
 148          */
 149         do {
 150                 c = *s++;
 151         } while (isspace_l(c, loc));
 152         if (c == '-') {
 153                 neg = 1;
 154                 c = *s++;
 155         } else if (c == '+')
 156                 c = *s++;
 157         if ((base == 0 || base == 16) &&
 158             c == '0' && (*s == 'x' || *s == 'X')) {
 159                 c = s[1];
 160                 s += 2;
 161                 base = 16;
 162         }
 163         if (base == 0)
 164                 base = c == '0' ? 8 : 10;
 165
 166         /*
 167          * Compute the cutoff value between legal numbers and illegal
 168          * numbers.  That is the largest legal value, divided by the
 169          * base.  An input number that is greater than this value, if
 170          * followed by a legal input character, is too big.  One that
 171          * is equal to this value may be valid or not; the limit
 172          * between valid and invalid numbers is then based on the last
 173          * digit.  For instance, if the range for longs is
 174          * [-2147483648..2147483647] and the input base is 10,
 175          * cutoff will be set to 214748364 and cutlim to either
 176          * 7 (neg==0) or 8 (neg==1), meaning that if we have accumulated
 177          * a value > 214748364, or equal but the next digit is > 7 (or 8),
 178          * the number is too big, and we will return a range error.
 179          *
 180          * Set any if any `digits' consumed; make it negative to indicate
 181          * overflow.
 182          */
 183         cutoff = neg ? -(unsigned long)LONG_MIN : LONG_MAX;
 184         cutlim = cutoff % (unsigned long)base;
 185         cutoff /= (unsigned long)base;
 186         for (acc = 0, any = 0;; c = *s++) {
 187                 if (c >= '0' && c <= '9')
 188                         c -= '0';
 189                 else if (c >= 'A' && c <= 'Z')
 190                         c -= 'A' - 10;
 191                 else if (c >= 'a' && c <= 'z')
 192                         c -= 'a' - 10;
 193                 else
 194                         break;
 195                 if (c >= base)
 196                         break;
 197                 if (any < 0 || acc > cutoff || (acc == cutoff && c > cutlim)) {
 198                         any = -1;
 199                 } else {
 200                         any = 1;
 201                         acc *= base;
 202                         acc += c;
 203                 }
 204         }
 205         if (any < 0) {
 206                 acc = neg ? LONG_MIN : LONG_MAX;
 207                 _REENT_ERRNO(rptr) = ERANGE;
 208         } else if (neg)
 209                 acc = -acc;
 210         if (endptr != 0)
 211                 *endptr = (char *) (any ? (char *)s - 1 : nptr);
 212         return (acc);
 213 }
 214
 215 long
 216 _strtol_r (struct _reent *rptr,
 217         const char *__restrict nptr,
 218         char **__restrict endptr,
 219         int base)
 220 {
 221         return _strtol_l (rptr, nptr, endptr, base, __get_current_locale ());
 222 }
 223
 224 #ifndef _REENT_ONLY
 225
 226 long
 227 strtol_l (const char *__restrict s, char **__restrict ptr, int base,
 228           locale_t loc)
 229 {
 230         return _strtol_l (_REENT, s, ptr, base, loc);
 231 }
 232
 233 long
 234 strtol (const char *__restrict s,
 235         char **__restrict ptr,
 236         int base)
 237 {
 238         return _strtol_l (_REENT, s, ptr, base, __get_current_locale ());
 239 }
 240
 241 #endif