xref: /titanic_50/usr/src/lib/libbc/libc/gen/common/strtol.c (revision 7c478bd95313f5f23a4c958a745db2134aa03244)

/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License, Version 1.0 only
 * (the "License").  You may not use this file except in compliance
 * with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */
/*      Copyright (c) 1984 AT&T */
/*        All Rights Reserved   */

#pragma ident	"%Z%%M%	%I%	%E% SMI"  /* from S5R2 2.1 */

/*LINTLIBRARY*/
#include <ctype.h>
#define DIGIT(x)	(isdigit(x) ? (x) - '0' : \
			islower(x) ? (x) + 10 - 'a' : (x) + 10 - 'A')
#define MBASE	('z' - 'a' + 1 + 10)

long
strtol(str, ptr, base)
register char *str;
char **ptr;
register int base;
{
	register long val;
	register int c;
	int xx, neg = 0;

	if (ptr != (char **)0)
		*ptr = str; /* in case no number is formed */
	if (base < 0 || base > MBASE)
		return (0); /* base is invalid -- should be a fatal error */
	if (!isalnum(c = *str)) {
		while (isspace(c))
			c = *++str;
		switch (c) {
		case '-':
			neg++;
		case '+': /* fall-through */
			c = *++str;
		}
	}
	if (base == 0)
		if (c != '0')
			base = 10;
		else if (str[1] == 'x' || str[1] == 'X')
			base = 16;
		else
			base = 8;
	/*
	 * for any base > 10, the digits incrementally following
	 *	9 are assumed to be "abc...z" or "ABC...Z"
	 */
	if (!isalnum(c) || (xx = DIGIT(c)) >= base)
		return (0); /* no number formed */
	if (base == 16 && c == '0' && isxdigit(str[2]) &&
	    (str[1] == 'x' || str[1] == 'X'))
		c = *(str += 2); /* skip over leading "0x" or "0X" */
	for (val = -DIGIT(c); isalnum(c = *++str) && (xx = DIGIT(c)) < base; )
		/* accumulate neg avoids surprises near MAXLONG */
		val = base * val - xx;
	if (ptr != (char **)0)
		*ptr = str;
	return (neg ? val : -val);
}