1 /* $Id: strtoul.c,v 1.2 2005/07/07 16:34:06 dron 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 

    32 #if 0

    33 static char sccsid[] = "@(#)strtoul.c	8.1 (Berkeley) 6/4/93";

    34 __RCSID("$NetBSD: strtoul.c,v 1.16 2003/08/07 16:43:45 agc Exp $");

    35 #endif

    36 

    37 #include <ctype.h>

    38 #include <errno.h>

    39 #include <limits.h>

    40 #include <stdlib.h>

    41 

    42 /*

    43  * Convert a string to an unsigned long integer.

    44  *

    45  * Ignores `locale' stuff.  Assumes that the upper and lower case

    46  * alphabets and digits are each contiguous.

    47  */

    48 unsigned long

    49 strtoul(const char *nptr, char **endptr, int base)

    50 {

    51 	const char *s;

    52 	unsigned long acc, cutoff;

    53 	int c;

    54 	int neg, any, cutlim;

    55 

    56 	/*

    57 	 * See strtol for comments as to the logic used.

    58 	 */

    59 	s = nptr;

    60 	do {

    61 		c = (unsigned char) *s++;

    62 	} while (isspace(c));

    63 	if (c == '-') {

    64 		neg = 1;

    65 		c = *s++;

    66 	} else {

    67 		neg = 0;

    68 		if (c == '+')

    69 			c = *s++;

    70 	}

    71 	if ((base == 0 || base == 16) &&

    72 	    c == '0' && (*s == 'x' || *s == 'X')) {

    73 		c = s[1];

    74 		s += 2;

    75 		base = 16;

    76 	}

    77 	if (base == 0)

    78 		base = c == '0' ? 8 : 10;

    79 

    80 	cutoff = ULONG_MAX / (unsigned long)base;

    81 	cutlim = (int)(ULONG_MAX % (unsigned long)base);

    82 	for (acc = 0, any = 0;; c = (unsigned char) *s++) {

    83 		if (isdigit(c))

    84 			c -= '0';

    85 		else if (isalpha(c))

    86 			c -= isupper(c) ? 'A' - 10 : 'a' - 10;

    87 		else

    88 			break;

    89 		if (c >= base)

    90 			break;

    91 		if (any < 0)

    92 			continue;

    93 		if (acc > cutoff || (acc == cutoff && c > cutlim)) {

    94 			any = -1;

    95 			acc = ULONG_MAX;

    96 			errno = ERANGE;

    97 		} else {

    98 			any = 1;

    99 			acc *= (unsigned long)base;

   100 			acc += c;

   101 		}

   102 	}

   103 	if (neg && any > 0)

   104 		acc = -acc;

   105 	if (endptr != 0)

   106 		/* LINTED interface specification */

   107 		*endptr = (char *)(any ? s - 1 : nptr);

   108 	return (acc);

   109 }