lib/libc/stdlib/_strtoul.h

   1 /* $DragonFly: src/lib/libc/stdlib/_strtoul.h,v 1.1 2005/03/17 15:09:01 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/_wcstoul.h,v 1.2 2003/08/07 16:43:03 agc Exp $
  33  */
  34
  35 /*
  36  * function template for strtoul, strtoull and strtoumax.
  37  *
  38  * parameters:
  39  *      _FUNCNAME  : function name
  40  *      __UINT     : return type
  41  *      __UINT_MAX : upper limit of the return type
  42  */
  43
  44 __UINT
  45 _FUNCNAME(const char *nptr, char **endptr, int base)
  46 {
  47         const char *s;
  48         __UINT acc, cutoff;
  49         char c;
  50         int i, neg, any, cutlim;
  51
  52         _DIAGASSERT(nptr != NULL);
  53         /* endptr may be NULL */
  54
  55         /* check base value */
  56         if (base && (base < 2 || base > 36)) {
  57                 errno = EINVAL;
  58                 return(0);
  59         }
  60
  61         /*
  62          * Skip white space and pick up leading +/- sign if any.
  63          * If base is 0, allow 0x for hex and 0 for octal, else
  64          * assume decimal; if base is already 16, allow 0x.
  65          */
  66         s = nptr;
  67         do {
  68                 c = *s++;
  69         } while (isspace(c));
  70         if (c == '-') {
  71                 neg = 1;
  72                 c = *s++;
  73         } else {
  74                 neg = 0;
  75                 if (c == '+')
  76                         c = *s++;
  77         }
  78         if ((base == 0 || base == 16) &&
  79             c == '0' && (*s == 'x' || *s == 'X')) {
  80                 c = s[1];
  81                 s += 2;
  82                 base = 16;
  83         }
  84         if (base == 0)
  85                 base = c == '0' ? 8 : 10;
  86
  87         /*
  88          * See strtol for comments as to the logic used.
  89          */
  90         cutoff = __UINT_MAX / (__UINT)base;
  91         cutlim = (int)(__UINT_MAX % (__UINT)base);
  92         for (acc = 0, any = 0;; c = *s++) {
  93                 if (!isascii(c))
  94                         break;
  95                 if (isdigit(c))
  96                         i = c - '0';
  97                 else if (isalpha(c))
  98                         i = c - (isupper(c) ? 'A' - 10 : 'a' - 10);
  99                 else
 100                         break;
 101                 if (i >= base)
 102                         break;
 103                 if (any < 0)
 104                         continue;
 105                 if (acc > cutoff || (acc == cutoff && i > cutlim)) {
 106                         any = -1;
 107                         acc = __UINT_MAX;
 108                         errno = ERANGE;
 109                 } else {
 110                         any = 1;
 111                         acc *= (__UINT)base;
 112                         acc += i;
 113                 }
 114         }
 115         if (neg && any > 0)
 116                 acc = -acc;
 117         if (endptr != 0)
 118                 /* LINTED interface specification */
 119                 *endptr = __DECONST(char *, (any ? s - 1 : nptr));
 120         return(acc);
 121 }