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_strtoul.h revision 1.3 
      1 /* $NetBSD: _strtoul.h,v 1.3 2012/03/22 15:57:29 christos 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 	unsigned 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 #if !defined(_KERNEL) && !defined(_STANDALONE)
     58 		errno = EINVAL;
     59 		return(0);
     60 #else
     61 		panic("%s: invalid base %d", __func__, base);
     62 #endif
     63 	}
     64 
     65 	/*
     66 	 * Skip white space and pick up leading +/- sign if any.
     67 	 * If base is 0, allow 0x for hex and 0 for octal, else
     68 	 * assume decimal; if base is already 16, allow 0x.
     69 	 */
     70 	s = nptr;
     71 	do {
     72 		c = *s++;
     73 	} while (isspace(c));
     74 	if (c == '-') {
     75 		neg = 1;
     76 		c = *s++;
     77 	} else {
     78 		neg = 0;
     79 		if (c == '+')
     80 			c = *s++;
     81 	}
     82 	if ((base == 0 || base == 16) &&
     83 	    c == '0' && (*s == 'x' || *s == 'X')) {
     84 		c = s[1];
     85 		s += 2;
     86 		base = 16;
     87 	}
     88 	if (base == 0)
     89 		base = (c == '0' ? 8 : 10);
     90 
     91 	/*
     92 	 * See strtol for comments as to the logic used.
     93 	 */
     94 	cutoff = ((__UINT)__UINT_MAX / (__UINT)base);
     95 	cutlim = (int)((__UINT)__UINT_MAX % (__UINT)base);
     96 	for (acc = 0, any = 0;; c = *s++) {
     97 		if (isdigit(c))
     98 			i = c - '0';
     99 		else if (isalpha(c))
    100 			i = c - (isupper(c) ? 'A' - 10 : 'a' - 10);
    101 		else
    102 			break;
    103 		if (i >= base)
    104 			break;
    105 		if (any < 0)
    106 			continue;
    107 		if (acc > cutoff || (acc == cutoff && i > cutlim)) {
    108 			acc = __UINT_MAX;
    109 #if !defined(_KERNEL) && !defined(_STANDALONE)
    110 			any = -1;
    111 			errno = ERANGE;
    112 #else
    113 			any = 0;
    114 			break;
    115 #endif
    116 		} else {
    117 			any = 1;
    118 			acc *= (__UINT)base;
    119 			acc += i;
    120 		}
    121 	}
    122 	if (neg && any > 0)
    123 		acc = -acc;
    124 	if (endptr != NULL)
    125 		/* LINTED interface specification */
    126 		*endptr = __UNCONST(any ? s - 1 : nptr);
    127 	return(acc);
    128 }
    129