common/lib/libc/stdlib/_strtol.h

   1 /* $NetBSD: _strtol.h,v 1.1 2008/08/20 12:42:26 joerg Exp $ */
   2
   3 /*-
   4  * Copyright (c) 1990, 1993
   5  *      The Regents of the University of California.  All rights reserved.
   6  *
   7  * Redistribution and use in source and binary forms, with or without
   8  * modification, are permitted provided that the following conditions
   9  * are met:
  10  * 1. Redistributions of source code must retain the above copyright
  11  *    notice, this list of conditions and the following disclaimer.
  12  * 2. Redistributions in binary form must reproduce the above copyright
  13  *    notice, this list of conditions and the following disclaimer in the
  14  *    documentation and/or other materials provided with the distribution.
  15  * 3. Neither the name of the University nor the names of its contributors
  16  *    may be used to endorse or promote products derived from this software
  17  *    without specific prior written permission.
  18  *
  19  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  29  * SUCH DAMAGE.
  30  *
  31  * Original version ID:
  32  * NetBSD: src/lib/libc/locale/_wcstol.h,v 1.2 2003/08/07 16:43:03 agc Exp
  33  */
  34
  35 /*
  36  * function template for strtol, strtoll and strtoimax.
  37  *
  38  * parameters:
  39  *      _FUNCNAME : function name
  40  *      __INT     : return type
  41  *      __INT_MIN : lower limit of the return type
  42  *      __INT_MAX : upper limit of the return type
  43  */
  44
  45 __INT
  46 _FUNCNAME(const char *nptr, char **endptr, int base)
  47 {
  48         const char *s;
  49         __INT acc, cutoff;
  50         unsigned char c;
  51         int i, neg, any, cutlim;
  52
  53         _DIAGASSERT(nptr != NULL);
  54         /* endptr may be NULL */
  55
  56         /* check base value */
  57         if (base && (base < 2 || base > 36)) {
  58 #if !defined(_KERNEL) && !defined(_STANDALONE)
  59                 errno = EINVAL;
  60                 if (endptr != NULL)
  61                         /* LINTED interface specification */
  62                         *endptr = __UNCONST(nptr);
  63                 return 0;
  64 #else
  65                 panic("%s: invalid base %d", __func__, base);
  66 #endif
  67         }
  68
  69         /*
  70          * Skip white space and pick up leading +/- sign if any.
  71          * If base is 0, allow 0x for hex and 0 for octal, else
  72          * assume decimal; if base is already 16, allow 0x.
  73          */
  74         s = nptr;
  75         do {
  76                 c = *s++;
  77         } while (isspace(c));
  78         if (c == '-') {
  79                 neg = 1;
  80                 c = *s++;
  81         } else {
  82                 neg = 0;
  83                 if (c == '+')
  84                         c = *s++;
  85         }
  86         if ((base == 0 || base == 16) &&
  87             c == '0' && (*s == 'x' || *s == 'X')) {
  88                 c = s[1];
  89                 s += 2;
  90                 base = 16;
  91         }
  92         if (base == 0)
  93                 base = (c == '0' ? 8 : 10);
  94
  95         /*
  96          * Compute the cutoff value between legal numbers and illegal
  97          * numbers.  That is the largest legal value, divided by the
  98          * base.  An input number that is greater than this value, if
  99          * followed by a legal input character, is too big.  One that
 100          * is equal to this value may be valid or not; the limit
 101          * between valid and invalid numbers is then based on the last
 102          * digit.  For instance, if the range for longs is
 103          * [-2147483648..2147483647] and the input base is 10,
 104          * cutoff will be set to 214748364 and cutlim to either
 105          * 7 (neg==0) or 8 (neg==1), meaning that if we have accumulated
 106          * a value > 214748364, or equal but the next digit is > 7 (or 8),
 107          * the number is too big, and we will return a range error.
 108          *
 109          * Set any if any `digits' consumed; make it negative to indicate
 110          * overflow.
 111          */
 112         cutoff = (neg ? __INT_MIN : __INT_MAX);
 113         cutlim = (int)(cutoff % base);
 114         cutoff /= base;
 115         if (neg) {
 116                 if (cutlim > 0) {
 117                         cutlim -= base;
 118                         cutoff += 1;
 119                 }
 120                 cutlim = -cutlim;
 121         }
 122         for (acc = 0, any = 0;; c = *s++) {
 123                 if (isdigit(c))
 124                         i = c - '0';
 125                 else if (isalpha(c))
 126                         i = c - (isupper(c) ? 'A' - 10 : 'a' - 10);
 127                 else
 128                         break;
 129                 if (i >= base)
 130                         break;
 131                 if (any < 0)
 132                         continue;
 133                 if (neg) {
 134                         if (acc < cutoff || (acc == cutoff && i > cutlim)) {
 135                                 acc = __INT_MIN;
 136 #if !defined(_KERNEL) && !defined(_STANDALONE)
 137                                 any = -1;
 138                                 errno = ERANGE;
 139 #else
 140                                 any = 0;
 141                                 break;
 142 #endif
 143                         } else {
 144                                 any = 1;
 145                                 acc *= base;
 146                                 acc -= i;
 147                         }
 148                 } else {
 149                         if (acc > cutoff || (acc == cutoff && i > cutlim)) {
 150                                 acc = __INT_MAX;
 151 #if !defined(_KERNEL) && !defined(_STANDALONE)
 152                                 any = -1;
 153                                 errno = ERANGE;
 154 #else
 155                                 any = 0;
 156                                 break;
 157 #endif
 158                         } else {
 159                                 any = 1;
 160                                 acc *= base;
 161                                 acc += i;
 162                         }
 163                 }
 164         }
 165         if (endptr != NULL)
 166                 /* LINTED interface specification */
 167                 *endptr = __UNCONST(any ? s - 1 : nptr);
 168         return(acc);
 169 }